Florina Stefanoiu

Laure Candy

Carlos Vaca-Garcia
email: carlos.vacagarcia@ensiacet.fr

Elisabeth Borredon

Kinetics and mechanism of the reaction between maleic anhydride and fatty acid esters and the structure of the products

Keywords: Activation energy / Alkenyl succinic anhydride / Ene-reaction / Maleinization / Reaction order DOi 10, 1002/ejlt, 200700181

Alkenyl succinic anhydrides (ASA) were obtained by reaction between maleic anhydride and high-oleic sunflower oil (HOSO) esters. A kinetics study of the maleinization of alkyl esters indicated that the mal einization reaction was second order overall and first order with respect to the individual reactants, and the activation energy was 77.2 ± 3.3 ltj'/mol in the investigated temperature range (185-225 °C). These results showed that the cis configuration and the central position of the double bond in HOSO esters facilitate the maleinization of the latter. On the contrary, the length of the linear ester moiety had no influence on the course of the maleinization reaction. Moreover, new evidence demonstrates that there are two different reaction mechanisms: ene-reaction and addition in allylic position with a 2 : 1 ratio, respec tively. This ratio was constant throughout the reaction, thus indicating that these mechanisms are inde pendent.

Introduction

Alkenyl succinic anhydrides (ASA) are widely used in the paper industry as paper sizing agents [START_REF] Neimo | Interna! sizing of paper[END_REF][START_REF] Scott | Sizing with synthetic sizing materials[END_REF]. Other common applications include: wood preservation agents [START_REF] Morard | Durability improvement of wood by treatment with methyl alkenoate succinic anhydrides (M-ASA) of vegetable origin[END_REF], additives for lubricants [4], and monomers for the fabrication ofther mosets as the anhydride moiety can react with diamines, diols, polyols or epoxy resins to yield unsaturated polyester-like resins [START_REF] Warth | Polyester networks based upon epoxidized and maleinated natural oils[END_REF]. ASA are obtained by reaction between maleic anhydride and an alkene, which is usually a petrochemical olefin, but vegetable oil derivatives can also be used.

On the one hand, industrial olefins for ASA production are straight or slightly branched 16 to 18 carbon chains. Iso merization of OE-olefins is performed first, to avoid terminal double bonds. The unsaturation (mainly trans) is therefore situated at any internai position in the chain and shows a stronger electronic density than OE-olefins.

On the other hand, the vegetable oil derivatives used for ASA synthesis are mostly unsaturated fatty acid esters. The main difference to olefins is not only the ester moiety, but also the double bond which is always located in the same position and exclusively in the cis configuration.

The maleinization of alkenes is a complex reaction and, currently, two different mechanisms are known: the ene-reac tion and the addition in allylic position. In this regard, the lit erature concerning the reaction between maleic anhydride and unsaturated molecules can be divided into three periods. Firstly, the studies of the reaction mechanism during the 1940's and up to the early 1950's employed fatty acids or fatty acid esters as alkenes. The mechanism of the maleinization was debated (ene-reaction versus cyclization or Diels-Alder type reaction) and, finally, the ene reaction was retained dur ing this period [START_REF] Bickford | The reaction of nonconjugated unsatured fatty esters with maleic anhy dride[END_REF][START_REF] Teeter | Polymerization of drying oils. III. Sorne observations on reaction of maleic anhydride with methyl oleate and methyl linoleate[END_REF][START_REF] Plimmer | The reaction of maleic anhydride with non conjugated unsaturated fatty materials[END_REF]. Secondly, the strong development of petrol resources in the early 1950's favored the production of ASA from straight or branched olefins or even from poly olefins [9, 1 O]. Since then and up to the 1990's, the studies aimed only at limiting secondary products by adding reaction catalysts (phenothiazine, aluminum acetylacetonate) [11], polymerization inhibitors (hydroquinone, dimethylsulfoxide) [11], or dispersing solvents (toluene) [12], but no discussion about the mechanism was proposed. Thirdly, with the rising interest in renewable resources observed since the early 1990's, new ASA have been synthesized again from vegetable oils and their derivatives. During this period, Holmberg and Johansson [START_REF] Holmberg | Addition of maleic anhydride to esters of mono-unsaturated fatty acid[END_REF] proposed, by using an oxidative cleavage technique, two different reaction mechanisms for the mal einization of ethyl oleate leading to different isomers in the reaction products. In the first path, the anhydride is grafted on either of the two ailylic positions of the alkene, leading to reaction products with the unsaturation retained at the 9-10 position (Fig. 1, reaction A). In the second path, the ene reaction occurs on either of the two ethylenic carbons, yielding products in which the double bond of the alkene has under gone an allylic shift (Fig. 1, reaction B). According to these authors, for the oleic esters, four isomers, only trans-config ured, are possible.

After the 1990's, no additional study has been published concerning the mechanism of the maleinization. Even if Holmberg and Johansson demonstrated that there were two routes, only the "ene-reaction" term continues to be incor rectly used, instead of the general "maleinization" term. One aim of the present work is to confirm ( or to disprove) the mechanism proposed by these authors and the structure of the resulting molecules by using advanced NMR, which is a direct analysis technique and constitutes an alternative to the indirect oxidative cleavage method. Another goal of the present work is to investigate the reaction kinetics of mal einization with vegetable alkenes, which have regained industrial importance. The results wiil be compared with the literature that gives information about the petrochemical unsaturated molecules [11,[START_REF] Metzger | Die En-Reaktion und ihre Anwendung auf ungesattigte Fettstoffe[END_REF][START_REF] Benn | The ene reaction of maleic anhydride with alkenes[END_REF]. High-oleic sunflower (HOSO) alkyl esters were chosen as starting materials. Reaction order, reaction rate constant and activation energy were thus investigated.

Materials and methods

Materials

Alcohols (ethanol, propanol, butanol, pentanol), oleic acid alkyl esters (methyl, ethyl, propyl, butyl, pentyl), maleic anhydride as well as dibutyltin oxide and CDC1 3 were all 99% pure and purchased from Sigma-Aldrich (France). All reagents were used without further purification.

Different alkyl esters of HOSO were used as raw mate rials for the synthesis of different ASA. The HOSO methyl esters [C 18 , 1 (86.2%), C 18 , 2 (6.0%), C 16 , 0 (3.1 %), C 18 , 0 (2.6%)] used in this work were provided by Novance (France). HOSO ethyl, propyl, butyl and pentyl esters were prepared from HOSO methyl esters by transesterification as described below.

Ethanol, propanol, butanol or pentanol (62.1-118.8 g), HOSO methyl esters (400 g) and dibutyltin oxide (6.7 g) were placed in a 500-mL three-neck reactor equipped with a nitro gen input, a mechanical stirrer and a reflux condenser. The temperature was gently raised to the boiling point of the alco hol. The reaction was conducted for several hours, until complete consumption of the methyl oleate (monitored by HPLC). Then, the HOSO alkyl esters were distiiled from the reaction medium between 160 and 170 °C under 1 mbar and immediately used for the maleinization. HPLC analyses confirmed that the maximum amount of residual methyl ester reaction was 1.1 %. The fatty acid profile for ail the alkyl esters was essentiaily the same as that of the HOSO methyl esters. The alkyl esters were therefore obtained in high yield by transesterification (>98%).

Synthesis and purification of ASA

Syntheses for the kinetics study

The reagent mass values are presented for the particular case of HOSO methyl esters with a molar ratio equal to 1. Ail the other syntheses followed the same protocol; only the quantities varied. HOSO methyl esters (80 g) and maleic anhydride (23.2 g) were introduced into a 250-mL three-neck reactor equipped with a magnetic stirrer and a condenser heated at 60 °C. The latter was necessary to allow maleic anhydride (m.p. 53 °C) to reflux. Prior to the reaction, oxygen was removed by applying a vacuum (40 mbar) for 30 minutes. The medium was heated at constant temperature (185-225 °C according to the experiment) for 8 h under static nitrogen atmosphere. The molar ratio was calculated by assuming that one mole of alkyl oleate consumes one mole of maleic arihydride whereas one mole of alkyl linoleate con sumes two moles. Sampling (0.2 mL) was carried out every hour and was analyzed by HPLC.

Syntheses and purification for the mechanistic study

The synthesis protocol was the same as above except that, at the end of the reaction, the medium was vacuum-distiiled. The unreacted maleic anhydride was distilled at 70 °C under 1 mbar. Unreacted HOSO alkyl esters were distilled at 160 and 190 °C under 1 mbar. ASA were finally distilled in only one fraction between 240 and 250 °C under the same pres sure. The purity and the structure of the distilled ASA were assessed by HPLC, infrared and NMR spectroscopy.

Preparation of ASA standards

ASA standards for analytical purposes were synthesized in the same manner as presented above (Section 2.2.2) by using oleic acid alkyl esters (98% purity) as raw materials, then vacuum-distilled. HPLC analyses were carried out to confirm the absence of residual alkyl esters and maleic anhydride. The purity of all the ASA standards was higher than 99.9%. Mass spectrometry and NMR spectroscopy analyses confirmed the desired structure.

Analytical methods

HPLC

The HPLC system was composed of a Dionex P680 pump and a Shodex refractometer detector RI 101 at 35 °C. A silica grafted C 18 Omnispher column of 25 cm and a diameter of 4.6 mm (Chromspher; Varian) was operated at 35 °C with a 1.5 mL/min (P = 70 bar) acetonitrile flow in the mobile phase. Alkyl oleates (98%; Sigma-Aldrich, France) and dis tilled ASA standards (see Section 2.2.3) were used as external standards to determine the composition of the reaction media.

lnfrared spectroscopy

A drop of liquid was put between K.Br windows to perform infrared analyses. Spectra were recorded in a JASCO FTIR 460 Plus apparatus in the 400-4000 cm-1 region with a 4 cm-1 resolution.

NMR spectroscopy

1 H and 13C NMR spectra were recorded in a Bruker Avance apparatus at 500 MHz. The samples were analyzed in CDC1 3 • J-modulated spin-echo (Jmod) and HSQC ( 1 Ja_c) techniques were employed. The coupling constants were calculated by the standard Bruker software.

Results and discussion

Study of the maleinization mechanism

The methodology used recognized that the ASA synthesis followed two paths, as described by Holmberg and Johansson [START_REF] Holmberg | Addition of maleic anhydride to esters of mono-unsaturated fatty acid[END_REF]. Then, 1 H and 13C NMR analyses were performed on pure molecules to assess: (i) the cis or trans configuration of the ASA and (ii) the relative concentrations of the carbon atoms labeled 8, 9, 10, and 11 in Fig. 1. These concentrations were used to determine the relative proportions of molecules following paths A and B. NMR was chosen as an analytical tool because it was the only method allowing the direct and quantitative measurement of the four positional isomers and it also provided their configuration.

The five pure (i.e. without residual reagents) ASA were named: methyl oleate succinic anhydride (ASAMe), ethyl oleate succinic anhydride (ASAEt), propyl oleate succinic anhydride (ASAPr), butyl oleate succinic anhydride (ASABu) and pentyl oleate succinic anhydride (ASAPe). They were ail clear yellow oily liquids (Gardner color from 5 to 7).

The FTIR spectra of oleic ASA presented the character istic bands of the expected groups. The major infrared peaks arising from anhydride carbonyl stretching were located at 1 785 and 1863 cm-1 . They also showed a stretch vibration band typical for five-membered cyclic anhydrides (i.e. succinic anhydride) at 917 cm-1 . The carbonyl stretch band of the alkyl ester appeared at 1 732 cm-1 . The band at 970 cm-1 indicated the presence of trans double bonds.

1 H NMR spectra of the samples showed the expected characteristic peaks. The example of ASAMe showed a peak at 5.5 ppm (m,2H) belonging to the -CH of the unsaturation. The peaks at 4.0 ppm (s,3H) and 1.5 ppm (m,2H) belonged respectively to the -CH 3 and the -CH 2 in the ester part. The peaks between 3.1 and 2.6 ppm (m,3H) were assigned to -CH belonging to the succinic link and to the anhydride moiety. The peaks at 2.2 ppm (t,2H) and at 1.5 ppm (m,2H) were respectively identified as the -CH 2 in the rx and � positions to the ester group and part of the unsaturated chain. The peak at 1.9 ppm (d,2H) belonged to the -CH 2 in the rx position to the unsaturation. Finally, the peak at 0.80 ppm (t,3H) can be assigned to the terminal -CH3 moiety of the alkyl chain. These spectra provided the confirmation of the chemical nature (grafted anhydride on fatty chain) of the distilled samples. Moreover, no peak was detected for residual reagents (maleic anhydride, alkyl esters), side-products or disubstituted ASA (reaction between maleic anhydride and linoleic esters). This observation strengthened the HPLC analysis that showed only the presence of oleic (C 18 : 1 ) ASA molecules (> 98%).

The configuration of the isomers was determined by 13C NMR. ASAMe, for instance, showed: 8 14.20 (CH ). A magnification of the 120-140 ppm region corresponding to the double bond carbons is presented in Fig. 2.

HSQC (lJH-C) analysis provided the coupling constants (Fig. 3). The values for the hydrogen chemical couplings (15-16 Hz) confirmed the presence of only trans compounds, which had already been observed [START_REF] Nahm | Transition state geometry and stereochemistry of the ene reaction between olefins and maleic anhydride[END_REF][START_REF] Metzger | Produkte der thermischen En Reaktion von ungesattigen Fettstoffen und Maleinsaureanhy drid[END_REF]. The cis configura tions possess smaller coupling constants (6-14 Hz).

13C NMR Jmod allowed the identification of ail the kinds of carbon atoms in the molecule. According to their environ ment, this technique showed that in the 120-140 ppm region only olefinic carbons were present. The absence of quaternary (C) carbon atoms in this zone demonstrates that maleic anhydride did not graft to a carbon belonging to the double bond. Moreover, the resonance zone of the ethylenic carbon atoms in the 13C NMR spectrum showed a number of eight signais (Fig. 2). This means that four different compounds were present. Paths A and B from Fig. 1 are therefore possi ble. The isomer distribution is related to the signal strength from which the relative isomer composition can be estimated. It is clearly seen that the concentration of products from path B is approximately two times greater than that of the products from path A. This implies that the relative isomer composition is given by either the ratio b/a = 2 or a/b = 2. It can also be observed that the most abundant compounds bear the most and the least deshielded ethylenic carbon atoms (around 137 and 126 ppm, respectively). The envi ronment of every ethylenic carbon (highlighted in Fig. 1) is practically equivalent with regard to the anhydride cyclic group. Therefore, deshielding will depend only on the dis tance of the double bond to the ester moiety. Only the mole cules obtained through path B are the ones that contain the C8 and C 11 ethylenic carbons. On the contrary, path A yields molecules bearing only C9 and C 10 ethylenic carbons. It can therefore be concluded that it is the ratio b/a that is equal to 2. The ene-reaction is thus twofold preponderant compared to the addition in allylic position. These results are in agreement with those obtained by Holmberg and Johans son [START_REF] Holmberg | Addition of maleic anhydride to esters of mono-unsaturated fatty acid[END_REF] by oxidative cleavage of the remaining olefinic bond of the adducts and the subsequent analysis of the products (indirect method). Moreover, this ratio remained constant during the course of the reaction (sampling and analyses performed every hour). This fact demonstrates that these reactions are parallel and independent.

Kinetics study

The linoleate esters (6%) contained in the HOSO esters were rapidly transformed into linoleic ASA (disappearance of the HPLC peak) within the first hour of reaction. The kinetics study was therefore carried out on the most abundant mole cule: oleic alkyl esters (86.2%).

Yield and conversion rate

The yield of ASA (Fig. 4) was calculated as the ratio be tween the number of moles of ASA determined by HPLC analysis and the number of moles of alkyl oleate initially introduced into the reactor. The conversion rate (Fig. 5) was calculated as the ratio between the number of moles of reacted alkyl oleate (evaluated by the difference after HPLC analysis) and the initial number of moles of alkyl oleate. Preliminary work concerning the synthesis of ASA from sunflower oleic acid methyl esters showed optimal reaction conditions (molar ratio MA/AE = 1.3) [START_REF] Quesada | Production of alkenyl succinic anhydrides from low-erucic and low-linolenic rapeseed oil methyl esters[END_REF][START_REF] Quesada | Prep aration of alkenyl succinic anhydrides from vegetable oil FAME[END_REF]. They were used in this work.

Both parameters increase with temperature. Nevertheless, at a given temperature and ratio MA/AE, the conversion rate was higher than the yield. It can be concluded that a part of the methyl oleate and maleic anhydride was not transformed into ASA but consumed by side-reactions to form oligomers, as described previously [START_REF] Quesada | Production of alkenyl succinic anhydrides from low-erucic and low-linolenic rapeseed oil methyl esters[END_REF][START_REF] Quesada | Prep aration of alkenyl succinic anhydrides from vegetable oil FAME[END_REF].

Reaction order and reaction rate constant (k)

The kinetics of the ene-reaction between maleic anhydride and various alkenes has been reported [START_REF] Metzger | Die En-Reaktion und ihre Anwendung auf ungesattigte Fettstoffe[END_REF][START_REF] Benn | The ene reaction of maleic anhydride with alkenes[END_REF] to be second order overall and first order with respect to the individual reactants. We assumed this dependence of the reaction rate on each reactant and worked with equimolar concentrations for the reagents. The linear plots of reciprocal concentration ver sus time for methyl oleate (Fig. 6) confirmed a first-order de pendence of the reaction rate on methyl oleate and maleic anhydride concentrations. From the slopes ofthese plots, the k values were evaluated for different reaction temperatures. They increased with temperature, from 0.005 L/mol/min at 185 °C to 0.01 7 L/mol/min at 225 °C. In every case, the reac tion order obtained for vegetables ASA with central cis con figuration was the same as that of the petrochemical unsatu rated molecules mainly trans reported in the literature [START_REF] Benn | The ene reaction of maleic anhydride with alkenes[END_REF].

Activation energy

From the Arrhenius-type plot (Fig. 7) the activation energy was calculated: E. = 77.2 ::':: 3.3 kJ/mol. It is interesting to compare this value with the results obtained by Benn and Dwyer [START_REF] Benn | The ene reaction of maleic anhydride with alkenes[END_REF], who investigated the reaction between maleic anhydride and dec-1-ene or dec-5-ene. They noticed that the lower electronic density of the dec-1-ene double bond resulted in a higher activation energy for the maleinization. This is the reason why oe-olefins are isomerized to obtain scrambled �, y, 8 ... olefins to increase the electronic density of the double bond and therefore increase their reactivity towards the eno phile [START_REF] Scott | Sizing with synthetic sizing materials[END_REF]. In this study, the electronic density of the double bond of methyl oleate is ostensibly the same as that of isomerized ole fins. The only difference between them is the double bond configuration. The activation energy for the maleinization of isomerized olefins reported in the literature [11] is 83.7 kJ/ mol. The difference in activation energy is small but signifi cant. It indicates clearly that cis-configurated molecules react more readily than trans-configurated ones.

Influence of the ester moiety

Yield and conversion rate results for ASAEt, ASAPr, ASABu, and ASAPe were similar to those obtained in the preliminary study on ASAMe. Conversion rate (Fig. 8) and Effect of the ester moiety on the conversion rate of alkyl oleate yield (not shown) plots followed the same trend. There is no significant influence of the length of the alkyl chains on these parameters. It was also observed that the order and the rate constant for the maleinization did not vary with the nature of the ester moiety. This group is far away from the reaction site, and the electronic density of the double bond remains essentially the same. In a comparative study that employed a molar ratio of MA/AE = 1.3, the calculation of the rate constant is based on the following equation: rate = kapparent [ alkyl oleate] °' Even though kapparent is different from k, for comparative purposes, the influence of the ester moiety could be investi gated. At 225 °C, kapparem was in the range of 0.036 ::':: 0.002 L/ mol/min for all the ASA. Again, there was no significant influence of the ester alkyl chain on the maleinization reaction. It can be presumed that the activation energy for each reac tion, from methyl to pentyl oleates, will be approximately the same. Therefore, the trans C 16 -C 18 olefins would require more energy for reaction than the cis vegetable molecules studied here, which bear 19 and up to 23 carbon atoms.

Conclusions

The results of this work can be summarized as follows:

(1) The maleinization of the alkyl esters proceeds by two competing mechanisms: ene-reaction (enophile + ene-com pound) and addition in the allylic position with a 2 : 1 ratio, respectively. The reaction between alkenes and maleic anhy dride should not be simply called "ene-reaction".

(2) There is always a total conversion of the cis double bond to a trans configuration.

(3) Maleinization of molecules bearing a center cis double bond follows a second-order reaction kinetics with an activa tion energy of 77.2 ::':: 3.3 kJ/mol, which is slightly lower than that of the scrambled trans olefins, even if the latter bear less carbon atoms.

( 4) The length of the linear ester moiety has no influence on the development of the maleinization reaction.

Figure 1 .

 1 Figure 1. Maleinization of alkyl oleates proceeding by two different routes.

Figure 2 .

 2 Figure 2. 13 C NMR spectrum of ASAMe.

Figure 3 .

 3 Figure 3. HSQC NMR spectrum of ASAMe.

Fi g ure 4 .Fi g ure 5 .

 45 Effect of reaction temperature on the yield of ASAMe. Effect of reaction temperature on the conversion rate of methyl oleate.

Fi g ure 6 .Fi g ure 7 .

 67 Second-order plot of the maleinization for different tem peratures. Molar ratio = 1. .J,I) -2,0 lnk -l;l _____ ___. ____ __. ____ _._ ____ ..... •1,0 Arrhenius plot for the maleinization of methyl oleate.

Acknowledgment

The authors would like to acknowledge the financial support of ONIDOL (Paris, France).

Conflict of interest statement

The authors have declared no conflict of interest.


Alexandre Coutant

Valérie Inés

Demerson De

La Ville

Malene Gram

Valérie

Nathalie Boireau

Yvonne Schütze

Die Gute Mutter

Motherhood, Advertising, and Anxiety: A Cross-Cultural Perspective on Danonino Commercials

come   L'archive ouverte pluridisciplinaire

Introduction

Being a mother has a significant impact on women's lives today, and becoming a mother and being a mother is proving to be more demanding from several perspectives 1 . One aspect of this is the ever-growing demands on pregnant women e.g. the growing number of products they are encouraged to avoid: hair dye, perfume, alcohol, smoking, various food products, etc 2 . Furthermore, there are growing demands on what mothers are expected to live up to once the child is born: washing all children's clothes before use to avoid chemicals; producing home-made baby foods from scratch; engagement in the child's development, schooling and career planning, etc 3 . In a 'risk' society there are plenty of things that should be avoided: from hidden chemicals or lurking diseases to the child getting hurt or not developing optimally.

Media, and especially advertising, is found to enact risks and nourish acknowledged or latent anxieties, and to 'destabilize' the feeling of safety held by the individual 4 . However, risk and anxiety are social constructions, and how they are played out differs, for example, with regard to food5 throughout European countries, due to cultural traditions about the symbolic significance of cooking or sharing meals, and also to a variety of systemic crises that have affected agricultural production in recent years (mad cow disease, milk contaminated by dioxin, vegetables presenting high rates of pesticides, bird flu, etc.).

Furthermore perceptions of what is nutritionally adequate also differ to some extent in different periods and places6 . This paper analyses how contextual and social aspects of food risk and anxiety are dealt with in the marketing of the Danonino brand when addressing mothers from children of 3 to 6 years of age across various European countries.

The present analysis is based on a corpus of 167 advertisements of the Danonino brand from France, Spain, Germany, Russia and Poland, broadcast between 2001 and 2007. We analyse how Danonino's commercial communications take into account, enact and co-generate anxieties connected to children and food in these European societies. This analysis of the commercials aimed at promoting a brand of food products for children, seeks to untangle the complex issues which inter-connect the concepts of anxiety, good mothering and children's appropriate food intake staged in the commercials. It is deemed particularly interesting to see how Danone stages anxiety in the five settings as both anxiety and good mothering are anchored in local contexts.

In this paper the actual health value of the Danonino dairy products is not discussed. The focus is on how these products have been promoted in the various European countries with regard to anxiety and responsibility in childcare. Moreover, the campaigns we analyse in this article were broadcast between 2001 and 2007, and thus should not be considered as representative of the present discourse of the brand as they do not reflect any recent modifications in the Danonino brand strategy. The Group's requirements for nutrition and health have been raised to the level of governance to address the issues of nutrition and public health. These commitments are reflected in its Nutrition and Health Charter, a document that includes in particular the practice of responsible methods of marketing and advertising to consumers and particularly children. (Danone Nutrition and Health Charter, 2009).

Literature review

Motherhood

The French philosopher Elizabeth Badinter criticizes the new and very heavy social demands on mothers she observes around her 7 . She argues that there is a growing pressure on women to limit their own desires and their activities to spend more time and take a greater part in the upbringing of their children. In her book "L'amour en plus" from 1980 she documents that motherhood and good mothering are complex social constructions and argues that motherhood is a social invention rather than a biological instinct, by illustrating how discourses about maternal love have been absent for centuries 8 . Today, women live their lives in a context of personal and cultural beliefs that all women are or at some point want to be mothers, since it is assumed that motherhood for women is a natural consequence of adulthood 9 and it constitutes a social taboo if a woman with children does not place motherhood at the centre of her identity 10 . The traditional model of the mother focused on the home and raising her child, has been very evident throughout the 20 th century, and still is today 11 . However, what characterises good motherhood is anchored in cultural values and has to be defined through the context of the place and time12 , e.g. whether or not it is expected that mothers breastfeed, and if it is acceptable for women to work.

Food and anxiety 7 Badinter, 2010, op. cit. 8 Also discussed by Zelizer, Viviana. Pricing the priceless child (New York: Princeton University Press, 1985). 9 Letherby, Gayle. "Mother or not? Mother or What? Problems of Definition and Identity." Women's Studies Int. Forum, Vol. 17 (1994). 10 Thompson, Craig J. "Caring Consumers: Gendered Consumption Meanings and the Juggling Lifestyle." Journal of Consumer Research, Vol. 22 (1996).

One of the key tasks in good mothering is to provide appropriate food for the child13 . This task is not evident even in recent decades which, in the Western world, have been characterised by affluence and abundance of food14 . Sociological studies on food consumption show that food is not just a matter of nutrition, but also of symbols and myths15 , and is an important expression of identity [START_REF] Atkins | Food in Society -Economy, Culture, Geography[END_REF] . Income, age, gender, cultural background and household composition also influence food consumption. A number of dilemmas are identified in relation to food culture: novelty vs. tradition, health vs. indulgence, convenience vs. care, and economy vs. extravagance. These dilemmas reflect consumers' and food providers' ongoing struggles [START_REF] Warde | Consumption, Food and Taste[END_REF] and consumer literature has established that the meaning attached to food products and food consumption is all the more important for the post-modern consumer who shifts between different lifestyles and identities, and in so doing draws on consumption patterns 18 even though food consumption is at the same time deeply rooted in habit and routine 19 . Furthermore food is intimately linked to social relationships [START_REF] James | Confections, Concoctions, and Conceptions[END_REF] , and even more so where children are involved [START_REF] Seiter | [END_REF] . At the same time food is a very important area of consumption, human beings eat to live, the child has to eat well to thrive, and food can be an effective means of negotiation in a power struggle [START_REF] Cook | Semantic provisioning of childen's food[END_REF] .

Despite being to some extent anchored in habit and routines, mothering and especially the responsibility related to providing the right food for children is mixed up with risk and anxiety related to more and sometimes ambiguous information about possible threats. The consumer faces permanent risks within the market economy 23 and a permanent concern about the "basic safety systems" 24 . Individuals are faced with uncertainty and doubt 25 , which also significantly increases the responsibility of the latter in managing their own individual riskand that of their children, in a time where 'project child' is supposed to be at the centre of a woman's life.

Consumer scepticism is increased by the diffusion of contradictory scientific results that tend to provoke both the increasing perception of the risk and the weakening of the credibility held by scientific messages 26 and the invisible threat of being 'potentially sick' 27 .

The sociologist Claude Fischler, elaborated the concept of the 'omnivore paradox', describing how the human being seeks to diversify his or her diet by arbitrating between several risks associated with the absorption of new foods, leading sometimes to neophobic food behaviours 28 . For the human being, this risk management results from of a wide range of physiological, but to a high extent also, cultural influences 29 . There is some consensus among researchers to consider that the "magic thought" that "we become what we eat", still prevails in our eating habits. Food thus constitutes an identity support, strongly contributing to the feeling of "ontological safety" evoked by Giddens, but the vague messages from the Health Authorities on foods 30 do not allow individuals to build their own eating competences or to consider themselves as competent eaters, particularly in the context of the health or agricultural scandals that have recently come to the forefront. Thus, the OCNI (Not Identified Eatable Object) coined by Fischler 31 raises an extremely distressing question for individuals: if we become what we eat, then what are we when we do not know what we eat? When taking the responsibility for feeding our child, how will we know what he or she will become? In a context where the body is less and less perceived as 23 Beck, Ulrick. Risk Society: Towards a New Modernity (New Delhi: Sage, 1992). 24 Giddens, Anthony. The Constitution of Society. Outline of the Theory of Structuration (Cambridge: Polity, 1984). 25 Bauman, Zygmunt. 'A Catalogue of Postmodern Fears' in Life in Fragments. Essays in Postmodernism reality, ed. Zygmunt Bauman (Oxford: Blackwell, 1995). 26 Giddens, Anthony. The Consequences of Modernity (Cambridge: Polity, 1990). 27 Coveney, John, 2006, op. cit. 28 Fischler, Claude. 'Food, self andidentity'. Social science information, Vol. 27 (1988). 29 Ibid.: 13. 30 Corbeau, Jean-Pierre. Nourrir de plaisir (Paris: Les Cahiers de l'Ocha, 2008). 31 Fischler, Claude. 1988, op. cit. "given" but as being "reflexively mobilized" 32 , the responsibility of parents in this future is underlined as being extremely worrying. Parents find themselves confronted with uncertainty about how to choose the best food for their young children.

Food in late modern societies constitutes a particularly representative field of socially constructed anxieties 33 . The growing industrialisation of foods, the rising cost of agricultural raw materials, the obesity pandemic, the inadequate information available to today's eaters (incomprehensible labelling, gaps in controls, inappropriate standards, misleading and/or ambiguous quality stamps, unverifiable claims) underline the risks in modern food products: "Industrialised food products give rise to questions which can rapidly become anxieties.

Where do they come from? What transformation have they undergone? Who has handled them?" 34 .

Perceptions of risk and anxieties differ within European countries, a reality which has been documented in a recent European study about trust in food 35 . This underlines on the one hand that local conditions play a role for risk perception but also that risk and anxiety are socially constructed. National culture has been found to play a significant role in the assessment of what can be perceived as 'good food'. In their study of feeding practices in five European countries, Synnott et al. 36 evidenced a number of cross-cultural differences. German and Scottish participants found that a 'healthy diet' should be as natural as possible and German participants believed that organic food ingredients were better for their infants. The Spanish and Italian participants were relying on authorities such as paediatricians for information on infant feeding practice 37 . A healthy diet was connected with variety and balance in Italy and Spain whereas in Germany, Scotland and Sweden it was almost exclusively associated with fruit and vegetables 38 . 32 Giddens, Anthony. 1990, op. cit. 33 Coveney, John. 2006, op. cit.; Green, Judith M., Draper Allison K. and Dowler Elizabeth A. 'Short cuts to safety: risk and 'rules of thumb' in account of food choice '. Health, risk and society, Vol. 5 (2003). 34 Poulain, Jean-Pierre. Sociologies de l'alimentation : Les mangeurs et l'espace social alimentaire (Paris: PUF, 2002): 39. 35

Media and Anxiety

This omnipresent risk that food products convey -and the anxieties which result from it -are co-produced through media messages. The fact that the media covers an array of topics that are enacted as important or worrying has been largely documented 39 . Researches on "media panics" suggest a reinforcement of a distressing mode of information treatment 40 . These distressing messages are also articulated in advertising. They depict a society deprived of institutions capable of guaranteeing the longevity and stability of social meaning, and introduce individuals to all the distressing excesses of social, economic, political, environmental, and health deregulation processes. There are numerous studies analysing the presence and the effects of distressing messages in advertisements 41 . Roland Marchand 42 , showed how, in the United States, the advanced techniques of marketing gradually took into account the concerns and anxieties of the ordinary consumer. The advertising communication specialists were the first to openly assert the 'therapeutic' dimension of their work, supposed to demonstrate that the company aims to solve some of the psychological discomfort -or lower the level of anxietythat the consumer might feel during his or her purchase activities, caused by a set of industrial changes which are complex and difficult to understand for an ordinary citizen; a discomfort that the advertisers enact and co-generate with the aim of offering a solution to relieve it 43 .

Advertising can be recognised as one of the "access points" 44 through which an institution can attempt to provide the pledge of confidence to the ordinary consumer. It proceeds through a "hyper-ritualisation" technique whilst strongly contributing to the establishment of standard expressions, normative attitudes or behaviours 45 "anxiety" developed in media messages which covers all kinds of informational categories [START_REF] Charaudeau | Une problématique discursive de l'émotion. À propos des effets de pathémisation à la télévision[END_REF] .

A possible strategy for advertisers thus consists of exposing the risks and their associated anxieties in modern society in order to attract and retain the target. This topic of "anxiety" appears to receive greater attention from the audience, leads to a better memorisation of the message and brings a greater opportunity of triggering a behavioural change in the public. This capacity of advertising to actually co-monitor individuals' views about food is judiciously moderated by Alan Warde who points out both the strong influence of social and cultural habits on individual consumption practices, which ends in routines that prevent consumers from being too heavily influenced by advertising discourses, and the fact that most commercial interactions develop within social institutions and membership groups which allow the exchange of information, advice, or delegation of purchases [START_REF] Warde | Consumption, Identity-Formation and Uncertainty[END_REF] . In the same way, authors relying on other pieces of Goffman's work have also raised the importance of social rituals in giving meaning to consumption practices and shaping them [START_REF] Marshall | Food as Ritual, Routine or Convention[END_REF] . The supposed strength of the commercials' hyper-ritualisation is indeed quite moderated by the social inclusion of the consumer. We can add that the growing suspicion among citizens and consumers about scientific results can be widened to all mediated discourses. These moderations can explain that many studies stress the difficulty for companies of dealing with anxieties in their communications strategies. Firstly, the individuals distressed by their lack of knowledge of industrial processes might seek alternatives to manufactured goods [START_REF] Moya | Consumers and producers: coping with food anxieties through 'Reconnection'?' Cultures of Consumption and ESRH-AHRB Research Programme[END_REF] . In addition, studies show that a mother's reaction to anxiety conveyed in advertising can quickly pass from trust to mistrust. When she considers the risks mentioned in a commercial are representative of her problems, the responsibility felt by the mother often leads her to undertake a behavioural change. However for a brand, dealing with risks and anxieties might immediately become very negative if the least manipulative inclination is perceived 50 .

Nevertheless, referring to risks and anxieties constitutes a topic regularly used by advertising executives in the field of maternity and childcare51 . The anxiety felt by mothers with regard to their responsibility for childcare, is then enacted to encourage them to adopt the products presented as protection against the new risks that have been identified for their child: "The risks and the problems that a minority -often a small minorityof infants and children must face is enacted in a universalized way, becoming potential risks for each infant and each child"52 . Prothero stresses that these risks and anxieties are exaggerated, often far removed from the actual risks to which the child is likely to be exposed, and that this has contributed to the world of standards and representations which make motherhood especially difficult for women in modern Western societies. Prothero clarifies two main axes through which the speeches about anxiety usually develop: the risk of hurting the child and the risk of not adequately fulfilling the maternal role.

Summing up from the above, motherhood and appropriate childcare and feeding are socially constructed and anchored in cultural values. Consumers find themselves in an arena with large amounts of information about potential risks, where everybody is potentially sick, and where they need to distinguish between advice, lack of trust, self-reflexion in a context where also cultural traditions, rituals, habits and routines are strong factors. However, what is trusted and what is considered 'safe' is associated with differing meanings across Europe. Media and particularly advertising plays a strong role in informing about risks and developing anxiety. In the following study on the Danonino brand it is particularly Prothero's two axes of the fear of hurting the child and not fulfilling the maternal role appropriately which have guided the analysis. 50 Cotte, June, Robin Coulter and Melissa Moore. 'Enhancing or disrupting guilt: The role of ad credibility and perceived manipulative intent'. Journal of Business Research, Vol. 58 (2005); LaBarge, Monica and John Godek. 'Mothers, Food, Love and Career-The Four Major Guilt Groups? The Differential Effects of Guilt Appeals'. Advances in Consumer Research, Vol. 33 (2006).

Methodology

Through a text analysisincluding verbal and visual rhetoric -of TV commercials, this qualitative and explorative study examines how a large corporation deals with risks and anxiety in their market communication.

The sample consists of commercials from five European markets broadcast between 2001 and 2007: 34 German, 37 French, 30 Spanish, 34 Polish and 32 Russian commercials. The sample is a convenience suitable sample offered by Danone®., but appears sufficient in order to offer an insight into how risks and anxieties about child-rearing and feeding are staged, to some extent differently from market to market, in the commercials. The selected countries were chosen to include various regional areas offering different social and cultural contexts for child-rearing and food intake. Danone® has carried out the campaigns in cooperation with local subsidiaries and agencies.

All the commercials were viewed by at least two of the authors. The qualitative analysis was carried out to search for themes relating to anxiety and motherhood inspired by the literature study, with an emphasis on the 'dual structure' of the situation played out in the commercial 53 food intake being presented as risky and safe -, and especially how the concept of 'tensive rhetoric' used by Patrick Hetzel in relation to brand communication is applied 54 . What Hetzel calls a 'tensive rhetoric' is a very common way advertisers use to enact a campaign concept. It dialectically associates two terms that appear, at first sight, as a paradoxical injunction 55 (e.g. "be natural!" or "be creative!") but with the purpose in the end to deliver a message that offers a way of solving such a paradoxical injunction, and that appeases the provoked tension felt by the targeted audience. Dealing with mothers' responsibilities in Western societies frequently leads advertisers to enact the paradoxical injunction of being a good mother and successfully achieving a professional career to present the product promoted as a way to resolve this tension.

As will appear from the following analysis, diverse forms of risk and anxiety were staged in different ways across the countries in the sample. Most focus is put on the German and French 53 Martens Lydia and Sue Scott. 2006, op. cit. 54 Hetzel, Patrick. Planète conso : Marketing expérientiel et nouveaux univers de consommation (Paris: Éditions d'organisation, 2002): 267-268. 55 Watzlawick, Paul. La réalité de la réalité. Confusion, désinformation, communication (Paris: Seuil, 1984).

analysis as the most diverse scenarios are seen in these sections of the sample, where the argumentation in the commercials goes far beyond mere physical aspects of nutrition.

Anxiety in the Danonino Commercials

The Danonino commercials cover various types. Almost 28% of the commercials address children directly by promising adventure and enacting various playful activities like discovery, search for excitement and risk-taking. The product is portrayed as a magical mediator that gives access to playfulness in a fictitious and fairy-tale world. The message is addressed to children through animated characters and the brand character. Another type of commercial addressing children uses special offers, gifts or play sets included in the products or offered through the packaging. The playing activity relates to arts and crafts, enabling the expression of individual artistic skills or fostering social relationships among peers. These commercials do not address nutritional issues and thus do not explicitly mention any kind of anxieties related to food intake. However, 72% of the commercials address mothers. One section of these commercials promotes the product by stressing the health benefits. The message content is focused on health and values of well-being excluding references to pleasure or entertainment. In contrast to the commercials aimed at children, these do not include any animated or brand characters.

A final section of the commercials addressing mothers is focused on children in activity. In these commercials, children are engaged in play, which is most often synonymous with physical activity and sport. The mother attends the child's performance and children portray enjoyment, excitement as well as a sense of competition. The voice-over addresses the mother and these commercials do not employ animated or brand characters either. Health is approached through a presentation of the functional properties of the product. The explicit enactment of anxiety is found mainly in this group of commercials aimed at mothers. The frequency of occurrence and content of different types of commercials differs from market to market as discussed by Gram et al. 56 In the following the use of anxiety is analysed, to trace -through verbal and visual rhetoric -the array of themes related to anxiety. Parental responsibility for child health and development, child-rearing and feeding and its subsequent anxieties are very clearly represented in the Danonino campaign, but this happens in differing ways in the various countries taken into account in the study.

The themes in commercials directed at children in all markets are fun and fantasy stories, and the topic addressed is about being strong and growing, and thereby being able to fight a dragon, a witch, an ice bear, etc. One could argue that implicitly this indicates an anxiety in children about not growing or not being strong enough to be able to manage on their own. The contradiction between the weak/not strong/not powerful child and the symbols of strengths (dragons, witches, bears) are resolved by the product offering strength and energy to the child.

In almost all commercials, the mother is clearly placed in the foreground as the main person responsible for ensuring her child's health. She is presented in testimonials to tell the audience how she used to be worried before she knew the brand and how she now feels safe with the product. 'Tensive rhetorics' is used here to present the tension between insecurity/anxiety related to the proper development of the child and the need to feel reassured, which is then resolved by the introduction of the product, offering, according to the commercials, a resolution to nutritional dilemmas and assuring that the child will eat healthy food and be grateful to the parent. The commercials that most use testimonial formats are the Russian, Polish and French commercials, where daily or frequent intake of the product is recommendeddirectly or indirectly in the commercial -to ensure adequate nutrition.

An example from a Russian commercial drawing on the testimonial form shows a mother who is picking up her child from Kindergarten or a playgroup, saying: "I have been told that in our country, half of the population of children are in deficit of calcium and iodine. Then I started to worry. "What to do if my child lacks calcium, too?

It seems like everything is fine, but maybe this is not the way it is; it is difficult to verify. It is important not to ruin anything from the start in childhood where everything is in the process of construction. When we learnt that Danonino is rich in microelements, we started to buy it more often. It is not a panacea, but it gives us, mothers, a certain self-confidence. Children quickly understand that they need iodine and calcium. Now Lesha [son] eats Danone's little yoghurts every day and I am happy". (Russia, 2007) lives that can be ruined from the start) and the product as the solution. In the German commercials, a very strong emphasis is placed on "without crystal sugar" and the fact that "no additives" are included. This shows that Danone is aware that German consumers are extremely wary of industrial foods and very concerned about organic production methods 57 . Furthermore, in the German sample, the Danonino product is frequently shown in proximity to fresh fruit. This focus is not very strong in the French and Spanish commercials and is totally missing in the Polish and Russian commercials, as these appear to be markets with a less accentuated suspicion on industrialised food production.

In the German sample, some commercials are portraying the possibility that the child cheats, by not eating the healthy foods provided by his/her mothere.g. as shown in the Cats commercial where children give their milk to the cat instead of drinking it and pushing away the fruit. A tension is thus presented between 'children's desires' and 'healthy eating'. There also appears to be a strong emphasis on the risk of conflict with the children when insisting on feeding them healthy foods that they do not like. This is a conflict that Danonino claims to be solving, by arguing that the brand products offer children a healthy food intake that children appreciate. 57 Synnott, Keith & al. 2007, op. cit. 'Playful' learning is portrayed as a theme in several ads across the sample as the opposite of 'painful' learning, which is a source of anxiety to parents.

Danone plays into European markets dealing with differing problems and anxieties. Just like French society, German society is very competitive, and in Germany, children need to show at a young age that they have the potential for academic work if they are later to have the opportunity to go to the prestigious Gymnasium. So the parent's and child's anxiety about the child not having energy for school work is real. In Russia, the risk is that children do not have access to basic nutrients to meet their physical growth needs and the anxiety staged in the commercials appears not to be concerned with schooling at all but rather with getting the right nutrients to grow and develop as a healthy child.

A more abstract anxiety about protecting children is staged in a French commercial, "La patinoire" (2003), where the little yoghurts are called: "little pots of strong bones". This commercial plays on the insecurity of parents as the plot is not about the concern for not knowing what is going on inside the child's body, but is rather about what might happen when the child is out of sight: "We cannot always follow [our children] but we do our best to prepare them for when we cannot be there" (Voice-over). This can be interpreted as an attempt to take away anxiety from the parents, but to stress the obligation of taking responsibility by preparing the child for situations where he will need to be autonomous.

French parents do spend more time away from their children compared with German parents, where the mother typically does not work (and rarely full-time) in opposition to France. 9, 10, 11, 12 and 13. Examples from French commercials (2003 and 2001) The child's anxiety about not growing is enacted in several German commercials, clearly directed at mothers rather than at children. In one German commercial where the child articulates his concern about not being big enough to play basketball with the bigger children, his mother calmly explains (while offering him a yogurt to eat), how he will have to be patient and reassuring him that as long as he eats properly he can be sure to grow.

A number of undesirable situations are sketched (the child rejecting healthy food, fragile bones, the child without energy, the worried mother), but at the same time Danonino is presented as the solution (offering calcium and vitamin D or iodine in a tasty and fun fashion, the child understands why these nutrients are important through pedagogical explanations and the mother feels safe and happy). At the same time the way this 'tensive rhetoric' is played out varies from being very explicit and almost threatening to implicit and positive across markets.

Discussion

Through the 'tensive rhetoric' set around a number of themes which, although treated differently according to national cultural backgrounds, appear to constitute cross-cultural axes, which are at play in the Danonino commercials aimed at mothers:  (A1) anxieties dealing with children's good physical health and normal growth portrays tension between parents' knowledge about food products and the question of the long-term effects of food intake on children's growth.  (A2) the risk of intellectual failure generates tension due to the difficulty of assessing the role that food plays in cognitive development.

 (A3) the risk that children might be excluded from their peer group, illustrates the tension between the reproduction of a cultural system within family circles and the system of values prevailing within the peer group  (A4) the mothers' aspiration to be loved by their children generates tension between the desire to maintain a peaceful relationship and the unavoidable conflicts associated with the responsibility of educating children  (A5) the mothers' busy diaries making them less present than the image of the 'perfect mother' requires, ends in tension between the social and professional requirements in modern Western societies and the responsibilities of the maternal bond (such as being present to protect the child)

The product is offered to children who are in a strong growth period and the physical measurable growth 'getting big and strong' or the fear of staying small and fragile is enacted in several ads across the sample, but staged differently across the national samples: through the doctor in France, through the emphasis on natural and pure ingredients in Germany58 , through the focus on extra iodine in Russia.

The wish for success in school or the risk of intellectual failure is found most explicitly in the German sample where a boy is actually seen bringing home his top grade, to more vague future dreams about becoming what one wants (a pilot, an explorer, a scientist, etc.) and having success, as seen in Russian commercials.

In a commercial entitled "Skate" (2002) aired in France, teenagers are gathered in a sports facility to practice skate. One of them is seated apart eating a yogurt and the others address him ironically saying he has childish tastes. As a response to their scornful comments, he then invites the leader of the peer group to take up the challenge of realising a difficult figure.

Having eaten the yogurt, he feels full of energy and self-assured, and successfully realises a perfect figure that ensures him a respectful acceptance by the peer group. The risk of being excluded from the peer group is sketched through mockery and the productinitially erroneously categorised as childish -directly contributes to enhance self-confidence to engage in peer relationships.

The desire to be loved by one's children at the same time as they are fed 'healthy food' is in some commercials sketched as a dichotomy in line with Warde's dilemma of health versus indulgence. The insistence on healthy food might mean conflict, but again the product is presented to solve this dilemma.

Finally the role of the mother is connected to anxiety. The mother is the main figure in most commercials where adults appear (a few men appear in more playful situations with the children). Mothers appear mostly in kitchens, smiling, well-dressed and energetic, where they often are seen to offer the product to children. As discussed above, mothers cannot always be there to protect their children, and especially French mothers are typically working fulltime outside the home, so the product is presented as this kind of protection.

The aim of this paper was to analyse how anxiety is part of Danonino's advertising campaigns targeting mothers across various European contexts, and how these anxieties are staged as inter-connected with the concepts of good mothering and healthy food.

The analysis shows that risk, anxiety and responsibility for children's health, along with psychological and social development, are enacted and co-generated in food advertising. In Danonino®'s commercials this is done in different ways, using implicitly and explicitly a more positive or a more anxious tone, depending on the social, cultural, and institutional characteristics of the target market.

Danonino's commercials stage five kinds of anxieties in the European market: responsibility for providing healthy food to meet the child's physical growth needs; anxieties associated with the responsibility for giving appropriate nutrients to foster children's intellectual development; anxieties linked to social exclusion from his/her peer group; anxieties raised by repeated conflicts particularly about food intake that may threaten family bonding relationships; and mothers' guilt for not being present enough for the child due to their own busy schedules.

The Danonino campaign takes into account cultural differences in advertising communication styles, in staging relevant topics of parental responsibility and correlated anxieties, and when mobilizing various authority figures to substantiate anxiety, to document product value, and to underline and relieve mothers' responsibility and anxiety. Whereas the German commercials stage anxieties over industrial food and insufficient nutrition, indirectly and positively, along with a strong focus on learning, French, Spanish, Polish and Russian commercials play more directly on risk and scientific expertise, suggesting what might happen from a physiological, psychological and even from a cognitive standpoint, if the child is not well-fed.

Our study highlights that advertising and anxiety about child rearing and child feeding are complex social constructions entangled in ideas of motherhood, and that what is defined as problems for children in their harmonious development, is deeply connected with cultural contexts.

Being a mother equals being expected to care, and it is understood that caring encompasses dealing with latent and invisible risks which are abundant in modern Western societies. As found in this study, Danonino®'s brand communication plays into this web of meanings, thus perpetuating, co-creating, actualizing but also putting up the archetypical figure of the

  56 Gram, Malene & al. "Communication on food, health and nutrition. A cross-cultural analysis of the Danonino brand and nutri-tainment." Journal of MarketingCommunications, vol. 16 (2010).

Figure 1 .

 1 Figure 1. Example from a Polish Danonino commercial (2002)

Figures 2

 2 Figures 2 and 3. 9 out of 10 children in France lack vitamin D / strong bones (French commercial, 2006).

Figures 4

 4 Figures 4 and 5. Children refusing fruit and milkexamples from German Danoninocommercial (2003)

Figures 6 ,

 6 Figures 6, 7 and 8. Children and nature regaining energy as they drink Danonino (Germancommercial, 2003)

Figures

  Figures 9, 10, 11, 12 and 13. Examples from French commercials (2003 and 2001)

  Kjaernes, Unni, Harvey Mark and Warde Alan. 2007, op. cit. 36 Synnott, Keith & al. "Parental perceptions of feeding practices in five European countries: an exploratory study." European Journal of Clinical Nutrition, Vol. 61 (2007).

37

Ibid.: 953 38 Ibid.: 954

  . Patrick Charaudeau identifies the topic of 39 McCombs, Maxwell and Donald Shaw. 'The Agenda-Setting Function of Mass Media'. The Public Opinion Quarterly, Vol. 36 (1972); Schneider, Tanja and Theresa Davis. 2010, op. cit. Moral Panics and the Media (Maidenhead: Open University Press, 2003). 41 e.g. Arthur, Damien, and Pascal Quester. 'Who's afraid of that ad? Applying segmentation to the protection motivation model'. Psychology & Marketing 21 (2004); Burnett, John J. and Robert E. Wilkes. 'Fear appeals to segment only'. Journal of AdvertisingResearch, 20 (1980).

	42 Marchand, Roland. Advertising the American Dream: Making Way for Modernity 1920-1940 (Berkeley:
	University of California Press, 1986).

40

Critcher, Chas.

43

Martens

Lydia and Sue Scott. 2006, op.

cit.

44

Giddens, Anthony. 1990, op. cit.

45

Goffman, Erving. Gender Advertisements (London: Mc Millan, 1979): 84.

Kjaernes, Unni, Harvey Mark and Warde Alan. Trust in Food -A comparative and Institutional Analysis (New York: Palgrave Macmillan, 2007).

Coveney, John. Food, Morals and Meaning. The pleasure and anxiety of eating(Oxon and New York: Routledge, 2006).

Johnston, Deirdre. D. and Swanson Debrah H. "Invisible Mothers: A Content Analysis of Motherhood Ideologies and Myths in Magazines." Sex Roles, Vol. 49, (2003).

Schütze, Yvonne. Die gute Mutter: Zur Geschichte des normativen Musters "Mutterliebe" (Bielefeld : B. Kleine, 1986).

Seiter, Ellen. Sold separately: children and parents in consumer culture. (New Brunswick: Rutgers University Press, 1993).

Coveney, John. 2006, op. cit.

Fischler, Claude. 'Food habits, social change and the nature/culture dilemma'. Social Science Information, Vol.19 (1980); Douglas, Mary. 'Standard Social uses of Food: Introduction'. In Food in the social order, edited byMary Douglas, 1-39 (New York: Russell Sage Foundation, 1984).

Prothero, Andrea. 'The F Word: The Use of Fear in Advertising to Mothers'. Advertising and Society Review, Vol. 7 (2006).

Douglas, Susan and Meredith Michaels. The Mommy Myth: The Idealization of Motherhood and How It Has Undermined All Women (New York: The Free Press, 2004): 300-301.

In line withSynnott, Keith & al. 2007, op. cit.

This research project is funded by a French national research grant awarded by the Programme National de Recherche sur l'Alimentation (PNRA).

Danonino brand has developed its communication in close contact with local subsidiaries representing local market knowledge. In all markets mothers almost exclusively are addressed as the main caretaker of the childboth with respect to food and otherwise. Anxieties are invoked in several ways related to protecting the child against visible and invisible physical, intellectual and social threats and in relation to feeling unsafe about not living up to parental responsibilities of providing the right nutrients or failing to carry out other parental duties well enough.

Especially in the southern and eastern European commercials a representative for science is brought in, represented by doctors or dentists, or other types of child experts such as school teachers. These experts offer a clear-cut solution to insecurity about how to solve anxieties related to lack of overview of nutritional advice. In all markets mothers, and in Germany even children, are brought in to give testimony of how they have solved their insecurities.

The commercials in several instances follow the pattern of 'destabilising' 59 the common conviction that children are generally well-fed in European countries and then offering a solution through the incorporation of the product in mundane child feeding routines.

Danonino®'s advertisements enact several concerns and anxieties that mothers have relating to their child's upbringing and healthy eating. The enactment of maternal role takes place along with the future aspirations for their child who, according to the commercials, should end up tall, healthy, a high achiever in school, popular among peers, in a loving relationship with his or her mother, who has been allowed to live her own life alongside parenting.

Here a paradox exists that food manufacturers addressing mothers cannot resolve as easily as when they use 'tensive rhetorics': whilst claiming to offer a solution to the above maternal anxieties, Danonino® can but nurture and make even more tangible some anxieties with regard to all the possible things that might go wrong in childhood in relation to the dominant ideals for a good upbringing 60 .

Conclusion

59 Martens [START_REF] Lydia | Under the kitchen surface: domestic products and conflicting contruction of home[END_REF]Sue Scott. 2006, op. cit. 60 Douglas, Susan andMeredith Michaels. 2004, op. cit.


Mathieu Mazza
email: mathieu.mazza@ensiacet.fr

Dan-Andrei Catana

Carlos Vaca-Garcia

Christine Cecutti

Influence of water on the dissolution of cellulose in selected ionic liquids

Keywords: Cellulose dissolution, Ionie liquids, Turbidimetric measurements

Cellulose (7% water) was thoroughly dis persed in various ionic liquids (IL) and the turbidity of the mixture was investigated to distinguish real dissolution from fine dispersion. The dissolving ability of 1-butyl-3-methylimidazolium chloride (BMIMCl know cellulose solvent) and 11 other commercial IL (not reported as cellulose solvents) was studied. From the latter, only 1,3-dimethylimidazolium dimethyl phosphate (DMIMDMP) could dissolve cellulose. The influence of water content on the real dissolution of cellulose in these two IL was investigated. The maximum theoretical amount of dissolved anhydrous cellulose in the IL was determined by extrapolation methodology at different temperatures. For cellulose in BMIMCl, it was 8.75 g/100 g of IL at 95 °C. DMIMDMP could achieve real cellulose dissolution only in a practically anhydrous system (2.3 g/100 g of IL at 30 °C) but dissolution was physically limited by high viscosity.

Introduction

The cellulose-containing materials and their deriva tives have been widely used in our society. In some physico-chemical processes, cellulose has to be dis solved. Solvents like LiCl/DMAc are used to perform reactions in homogeneous media [START_REF] Vaca-Garcia | Cellulose esterification with fatty acids and acetic anhydride in lithium chloride/N,N-dimethylacetarnide medium[END_REF][START_REF] Seoud | Organic esters of cellulose: new perspectives for old polymers[END_REF] and solvents like NMMO and cuen have been used as non-derivatizing solvents for regeneration [START_REF] Johnson | Solvents for cellulose[END_REF][START_REF] Heinze | Chernical functionalization of cellulose[END_REF]. For both applications, ionic liquids (IL) are currently attracting much attention because they are liquid at relatively low temperatures ( <100 °C) and are described as chemically and thermally stable, non flammable, and non-volatile. Their extremely low vapour pressure is the leading characteristic in pro cesses where volatile organic compounds (VOC) must be avoided. As far as VOC emissions are concemed, IL are more environmentally friendly than traditional organic solvents [START_REF] Seoud | Applications of ionic liquids in carbohydrate chemistry: a window of opportunities[END_REF].

Diff erent studies have shown that cellulose can be dissolved in methylimidazolium salts, especially l-butyl-3-methylimidazolium chloride (BMIMCl) [START_REF] Swatloski | Dissolution and processing of cellulose using ionic liquids, cellulose solution, and regenerating cellulose[END_REF][START_REF] Swatloski | Dissolution of cellulose with ionic liquids[END_REF] and 1-allyl-3-methylimidazolium chloride (AMIMCl) [START_REF] Zhang | 1-Allyl-3-methylirni dazolium chloride room temperature ionic liquid: a new and powerful non-derivatizing solvent for cellulose[END_REF], ammuniom salt like benzyldimethyl(tetradecyl)ammonium chloride (BDTACl) and pyridinium salt like l-butyl-3-methylpy ridinium chloride (BMPyCl) [START_REF] Seoud | Applications of ionic liquids in carbohydrate chemistry: a window of opportunities[END_REF]). In all these cases, the dissolution of the cellulose is also due to the action of the chloride anions, which internet with the hydroxyl groups of cellulose by disrupting the hydrogen bonds in the biopolymer [START_REF] Moulthrop | High-resolution 13C NMR studies of cellulose and cel lulose oligomers in ionic liquid solutions[END_REF]). These interactions have been put in evidence by NMR in solutions of cellulose in BMIMCl at 5% at 90 °C [START_REF] Moulthrop | High-resolution 13C NMR studies of cellulose and cel lulose oligomers in ionic liquid solutions[END_REF][START_REF] Remsing | Mechanism of cellulose dissolution in the ionic liquid 1-N-butyl-3-methylirnidazolium chloride: a 13C and 35137 Cl NMR relaxation study on model systems[END_REF]. In other works, the maximum cellulose concentration in BMIMCl has been reported. Different values are reached depend ing on the temperature and on the heating device: 6 wt% at 80 °C [START_REF] Schlufter | Effi cient homogeneous chernical modification of bacterial cellulose in the ionic liquid 1-N-butyl-3-methylimidazo lium chloride[END_REF], 10 wt% at 100 °C or up to 25 wt% if the dissolution is carried out using a microwave heating system (150 °C maximum) (Swatlo ski et al. 2002(Swatlo ski et al. , 2003)). Moreover, the solubility depends also on the origin of cellulose and its degree of polymerisation [START_REF] Heinze | Ionie liquids as reaction medium in cellulose functionalization[END_REF][START_REF] Barthel | Acylation and carbanilation of cellulose in ionic liquids[END_REF].

In all these studies, the assessment of dissolution was done by: static and dynamic light scattering methods [START_REF] Chrapava | The investigation of the influence of water and temperature on the LiCl/DMAc/cellulose system[END_REF], NMR [START_REF] Moulthrop | High-resolution 13C NMR studies of cellulose and cel lulose oligomers in ionic liquid solutions[END_REF]) and visual methods [START_REF] Swatloski | Dissolution of cellulose with ionic liquids[END_REF].

There is a possibility that confusion arises between real dissolution (complete solvation of the cellulose molecules) and fine dispersion of cellulose particles or even aggregates formation during or after disper sion in the solvent. In regeneration processes, it is important to reach total dissolution of cellulose in order to obtain a homogeneous product.

Thus, one of the aims of our study is to propose an alternative method to differentiate real dissolution of cellulose. Turbidimetry was selected as a simple technique.

A second aim of our study was to quantify the negative influence of water when dissolving cellulose in IL. Water can corne from (i) the hygroscopicity of IL, (ii) the initial cellulose water content, and (iii) the process, in particular when precipitating the dissolved cellulose. Therefore this information can be exploited in different manners, for instance, the following questions can be answered: how much undried cellulose can one dissolve in a particular ionic liquid? In what extent the concentration of cellulose can be increased if cellulose is previously dried? What is the minimum quantity of added water to precipitate cellulose?

Materials and methods

Materials

Twelve commercial IL (Table 1) were purchased from Solvent Innovation (Koln, Germany) and Solv ionic (Toulouse, France). They had a purity of minimum 98% and were used as received. Sigma Aldrich (France) fumished o:-cellulose having a water content of 7% (determined by thermogravimetry and Karl Fischer methods) and was used without further drying in this study. Cellulose acetate (DS = 2.4) and tetrahydrofuran (THF, 99.5% purity) were purchased from Sigma-Aldrich (France). NaCl (99.5% purity) was purchased from Acros Organics (Belgium).

Turbidimetric measurements

Turbidity was measured with a nephelometer featuring a scattered light detector perpendicular to the light beam (Fig. 1). The correlation between transmitted and scattered light constitutes a precise evaluation parameter of the presence of non-dissolved partiel es in a solution as they are bigger than the wavelength of the incident light (860 nm). The units of turbidity from a calibrated nephelometer are called Nephelometric Turbidity Units (NTU). Calibration was done between 1 and 1,000 NTU. The latter corresponds to a milky opaque sample.

Dissolution of cellulose in ionic liquids

Turbidimetric clear glass vials containing a precise quantity of ionic liquid (around 15 mL) and a magnetic stirrer were placed into a heating oil bath. The use of a hot water bath was avoided to limit the water uptake by hygroscopy. Small precise amounts of cellulose (around 10 mg) powder were added discretely into the vials. In between each addition, at least 15 min were allowed for dissolution and turbidity was measured until a stable NTU value was reached. Tests were realised at 90 °C for BMIMCl and at 30 °C for the other IL, which are in liquid form at room temperature.

Influence of the water content

Initial solutions of cellulose in BMIMCl and 1,3dimethylimidazolium dimethylphosphate (DMIMD MP) were prepared at 125 and 105 °C, respectively in order to evacuate the ambient moisture. Three different cellulose concentrations (0.5, 1, and 2 g in 100 g of IL) were used. The solutions were put into vials with a magnetic stirrer and placed in an oil bath at controlled temperature (85, 90 or 95 °C).

Table 1 Ionie liquids used in this study

Referenee on

Ionie liquid CAS Fig. 3 number

1 l-Butyl-3-methylimidazolium ehloride BMIMCI 79917-90-1 2 l-Butyl-3-methylimidazolium tetrafluoroborate 174501-65-6 BMIM BF4 3 1-Ethyl-3-methylimidazolium 2(2-methoxyethoxy) n.a. ethylsulfate 4 AMMOENG 100 n.a. 5 1-Ethyl-3-hydroxymethylpyridinium ethylsulfate n.a. 6 1-Ethyl-3-methylimidazolium ethylsulfate 342573-75-5 7 1,3-Dimethylimidazolium dimethylphosphate 654058-04-5 DMIMDMP Formula F\ __, N V N � Cl F A. I_ __-NV N� F-�-F F F\, [ 019 ] __.-N 0 N -----./ -+--a� ';l'o 0 Cocos......._ N .,.� O � O H ÜCcc� - 1~0 __/ v-f-o � OH �o m+n=4-14 O O H q, .,,,0- /s ) ) 'à 0 A.
,, .,.,.0

0/ �\ __-NV N \ ) 0 "o F\. ' __-N V N "
/? F 0 F , , ,, N , S --f- xs, /J N 'o O F / � F F Tallow , N .� O � OH __I "v-f--o � OH 0 �/�o r o m+n=14-25 F\+ ...--N V N \ .,,,N� wc C�N � O _ O F F ,, / N -�J- xs, , 11 F �N� O F d ) 0 -
,, ,,.a o� �,

Results and discussion

Validation of the turbidimetric principle

Turbidity is the cloudiness of a fluid caused by particles in suspension. They will scatter a light beam passing through the sample. This property is consid ered as a significant consequence of solid particles in suspension. More light reaches the scattering detector if there are solid particles scattering the source beam.

To some extent, how much light is scattered by a given amount of particles depends on the properties of the latter: shape, colour, and reflectivity. In our case, we will measure particles of a unique solute: cellulose. Comparisons can therefore be made.

Before testing the proposed method on cellulose, the principle of solubility evaluation by turbidimetry was validated using independently an ionic com pound (NaCl) and a linear polymer (cellulose acetate) dissolved in water and tetrahydrofuran, respectively.

Turbidity is expected to keep reasonably constant as much as the solute is perfectly soluble. When the maximum solubility is reached, the newly added solute remains solid and turbidity is expected to increase sharply.

The predicted behaviour of turbidity was con firmed with the study of the dissolution of NaCl in water at 30 °C (Fig. 2). Turbidity was perfectly constant then increased sharply at concentrations higher than 38 g/100 g water. This result is Thus, the perfect dissolution of a salt in water does not increase the turbidity.

In the case of a polymer, the dissolution of cellulose acetate in THF (Fig. 2) gave a linear trend with a small slope, which can be considered almost constant with regard to the whole scale of turbidity (1-1,000 NTU). The end of solubility could not be reached because the solution became tao viscous to be stirred preventing the homogenisation of the sample. Nevertheless, the main principle could be confirmed for ionic compounds and macromolecules.

Dissolution of cellulose in selected ionic liquids

All the commercial IL listed in Table 1 were tested to assess their ability to dissolve cellulose. Although undried cellulose was used in the experiments, the concentration values were reported on a dry basis.

Only two of the IL were able to dissolve cellulose: BMIMCl (number 1, already known: reference) and DMIMDMP (no. 7, not previously described as cellulose solvent). These two systems show practi cally fiat lines in a plot of turbidity versus concentration (Fig. 3). The other 10 IL showed an immediate and constant linear rise of the turbidity when the cellulose concentration was increased. The turbidity values were significantly high to indicate the presence of solid particles even at the lowest concentrations. The rise in turbidity for a given increase in cellulose concentration was different according to the ionic liquid. The slopes of the lines in Fig. 3 that correspond to the biphasic systems vary from 569 to 3,397 NTU/g cellulose. It is evident that the interactions between cellulose and IL are different and affect the light dispersing properties of the particles. Three groups of lines can be distinguished in Fig. 3 according to the slope values. It is interest ing to observe that the IL that share the same type of anion belong to the same group: bis(trifluoromethyl sulfonyl)imide for IL 8 and 11, alkylsulfate anions for IL 3, 4, 6, 9, and 12. The interactions affecting light scattering seem to be independent of the cation of the ionic liquid.

The maximum solubility of a-cellulose in BMIMCl and DMIMDMP was determined by addi tion of cellulose portions to the IL to put in evidence an abrupt change of turbidity (Fig. 4). The experi ments were done at 90 °C for BMIMCl and 30 °C for 3 50 - ---------------� 3 00

5' 250 1- � 200 � '6 150 :c :i 100 1- 50 DMIMDMP End of solubility \ .�(• • • •• ••• •••• •••• • \ � • • • •• • • 1 BMIMCI .. � .. ••• ott:i:,:j���.:,__m�m�m�m�-m�.---1 0 2 3 4 5 6 7 8
Cellulose concentration (g / 100 g of ionic liquid) (dry basis)

Fig. 4 Maximum solubility of cellulose in BMIMCl and DMIMDMP

DMIMDMP according to their melting points (Table 1).

The curve of the BMIMCl system showed a neat increase of slope at 6.2 g/100 g IL. This value is in agreement with the values reported by Swatloski et al. (11.1 g/100 g IL at 100 °C and 3.1 g/100 g IL at 70 °C).

In the DMIMDMP system, the end of cellulose solubilisation could not be detected by turbidimetry because the solution became too viscous to be stirred. This limit was reached at 2.3 g/100 g IL. Nonethe less, this value corresponds to the highest cellulose concentration that can be reached in this ionic liquid under the practical conditions.

Influence of the water content

Oven-dry cellulose was not used for this study. We decided to keep using the standard cellulose containing 7% water (moisture at equilibrium) to avoid the hornification phenomenon that can reduce severely its solubility. Results were, however, expressed on a dry basis.

In a system in which cellulose is perfectly dissolved, the addition of a non-solvent (in this case, water) perturbs the solvation of the biopolymer. Turbidity is expected to remain constant as far as cellulose is still soluble but when the maximum water content in the solution is reached, cellulose would precipitate and the turbidity is expected to increase sharply. After precipitation of all the cellulose molecules, the turbidity should keep constant. The expected behaviour was verified in the case of the BMIMCl/cellulose solutions. An abrupt increase of the turbidity was observed at the beginning of precipitation. Turbidity starts to level off when little cellulose remains in solution and much cellulose passes in suspension (Fig. 5).

The start of the cellulose precipitation was deter mined by the tangent method. For an initial solution of 1 g cellulose/100 g BMIMCl, precipitation occurred at 0.1872 g water/g BMIMCl (Fig. 5). It is evident that this value, which represents the maxi mum water content in a homogeneous cellulose/IL system, depends on both the concentration of cellu lose and the temperature. The values determined for different conditions are given in Table 2.

The relation between these values and the initial cellulose concentration at constant temperature showed a linear trend (Fig. 6). The intersection of the straight line with the Y-axis represents the maximum theoretical amount of cellulose that can be dissolved in BMIMCl at a given temperature when the water content in the solution is zero. At 95 °C, this value is 8.75 g/100 g of BMIMCl, i.e., 8.0 wt%. At 90 °C, the expected value decreases to 5.87 g/100 g IL, which is in agreement with the experimental result reported above (6.2 g/100 g IL).

The small difference is justified by the uncertainty of the extrapolation.

The maximum solubility values for the reported by Swatloski et al. are also shown in Fig. 6 as points on the Y-axis. From our experimental and the reported values, we can plot the maximum solubility of cellulose in anhydrous conditions as a fonction of temperature (Fig. 7). The behaviour is not linear but follows a classic parabolic trend observed elsewhere for most solutes in classic solvents.

In the case of DMIMDMP at 95 °C, the turbidity increased immediately after the first addition of water to the cellulose solution. The increase was observed regardless of the cellulose concentration (0.5, 1, and 2 g of cellulose in 100 g of DMIMDMP). As more water was added in the solutions, the turbidity kept increasing (Fig. 8). It seems that perfect dissolution of cellulose in this ionic liquid is possible only in practically anhydrous conditions, as those used to trace Figs. 3 and4. In addition, we verified that water and DMIMDMP form a miscible clear solution, as demonstrated by the fiat line of Fig. 8. Therefore, the increasing behaviour of the turbidity is only due to No description of the cellulose dissolution mecha nism was found in the literature that can help understand this behaviour. In contrast, these results may help in the future to understand the dissolution mechanism of this new ionic liquid.

Conclusion

It was demonstrated that turbidimetric measurements are a method allowing to distinguish real dissolution from fine suspension of cellulose in IL. Only one, among the selected new 11 IL tested, could dissolve cellulose (DMIMDMP).

The influence of water in the dissolution of cellulose was quantitatively evaluated. Cellulose could be dissolved in BMIMCl at different water contents. The more water, the less concentration of cellulose in solution is obtained. The maximum theoretical amount of anhydrous cellulose in solution was 8.75 g/100 g of BMIMCl at 95 °C determined by extrapolation methodology. All the results are in agreement with those from literature .

Tests on DMIMDMP showed that the cellulose can be perfectly dissolved only if the system is practically anhydrous. The maximum obtained value was 2.3 g/100 g IL at 30 °C. More cellulose could be theoretically dissolved but the high viscosity of the solution avoided further dissolution. A small amount of water added to the system leads to the formation of cellulose aggregates.

  -----+----Light source

Fig. 1

 1 Fig. 1 Principle of a nephelometer

Fig. 2

 2 Fig. 2 Turbidity versus solute concentration: NaCl in water and cellulose diacetate in THF

Fig. 3

 3 Fig.3Turbidity versus cellulose concentration for 12 ionic liquids. For legend, see Table1

  a;=i=;.��a,;ie"r=�f""'t• -:S-q,:,:,. -;5-:=;-�--"'f•�• -,::,:-;=:-"'i• -e::oe;:-,::,e-e;e:--��$:::;:::=;�:::!'.!;-::ti;=:::::;• -�-�-:;2:::..-�e è.:..f• g / 100 g of ionic liquid {dry basis))

Fig. 5

 5 Fig. 5 Influence of water content in the turbidity of cellulose solutions. Example given for 1 g of cellulose in 100 g of BMIMCl at 95 °C. Maximum water content before precipita tion was 0.1708 g of water/g of BMIMCl

Fig. 6

 6 Fig. 6 Linear behaviour of cellulose in solution in BMIMCl as a function of maximum water content at constant temperature. Circles represent values from Swatloski et al. 2002

Fig. 7 Fig. 8

 78 Fig. 7 Maximum theoretical solubility of cellulose in anhy drous conditions at different temperatures. Square-shaped points are experimental values. Circles are values obtained from Swatloski et al. (2002)

Table 2

 2 Maximum water content (including cellulose moisture content) before precipitation for different cellulose concentrations in BMIMCl at different temperatures

	Temperature ( 0 C)	0.5 g of cellulose	1 g of cellulose	2 g of cellulose
		in 100 g of BMIMCl	in 100 g of BMIMCl	in 100 g of BMIMCl
	95	0.1967	0.1872	0.1614
	90	0.2934	0.2702	0.2120
	Values given in g of water/g of BMIMCl

Acknowledgments

The authors wish to thank TEMBEC France and the ANRT agency (France) for financial support.