Juliana Melendrez Ruiz
email: juliana.melendrezruiz@inrae.fr

Stéphanie Chambaron

Erick Saldaña

Sandrine Monnery-Patris

Gaëlle Arvisenet

Using CATA tests to capture consumers' mental representations elicited by images of pulse-based food products with different levels of processing

Keywords: CATA, mental representations, food choices, pulses, food processing

Consumption of pulses plays a key role in achieving a healthier and more sustainable diet. Despite the increased availability of pulse-based foods on the French market, pulse consumption in France remains below recommended levels. The objective of this study was to capture French consumers' mental representations of various pulse-based foods with different levels of processing, using a Check-All-That-Apply (CATA) questionnaire with food images. We used CATA questionnaires, in two separate studies, to capture two aspects: consumers' beliefs about the products presented in the study, and the characteristics of those products, according to consumers. In Study 1, twelve images of pulses were presented (unprocessed, processed, and ready-to-eat) to investigate whether and how consumers differentiate between pulse-based products with different recipes and levels of processing. In Study 2, parallel CATA questionnaires were used: one with images of pulse-based products, and one with images of vegetables. We wanted to discover whether the factors underlying different representations for pulse-based products were specific to pulses, or were also observed with another family of food products. Results showed that products were differentiated more by their level of processing than by their main ingredient. Participants had more positive attitudes toward pulse products that were unprocessed, processed, or "new ready-to-eat", than toward other ready-to-eat pulse products (whether canned or frozen). Our results also highlighted that, in consumers' mental representations of pulse-based products, packaging format is a negligible factor in comparison with the nature of the product itself.

Introduction

Over the last few decades, there has been an increasing need to promote healthier and more sustainable food choices. Pulses are considered to have many assets aligned with this objective. The FAO defines pulses as a type of leguminous crop that is grown mainly for human consumption, such as beans, chickpeas, lentils, and dried peas. This definition excludes other leguminous crops, such as green peas, which are classified as green vegetables, and crops used for oil extraction, such as soybeans (FAO, 2016). Pulses are very nutritious and their consumption is associated with health and nutritional benefits.

Growing pulses helps to maintain the environmental sustainability of agriculture [START_REF] Rawal | The Global Economy of Pulses[END_REF]. Despite the rising interest in pulses internationally, their consumption in France remains low, at only 2 kg per person in 2018 [START_REF] Agreste | Étude individuelle nationale des consommations alimentaires 3 (INCA 3) Edition Scientifique[END_REF], well below the global average consumption of 7.6 kg per person per year [START_REF] Rawal | The Global Economy of Pulses[END_REF]. A slightly more recent study showed that, in France, there is no well-established social representation of pulses as a food family [START_REF] Melendrez-Ruiz | Do French Consumers Have the Same Social Representations of Pulses as Food Industry Professionals?[END_REF]. An earlier study had suggested that, for French people, the difficulty of preparing pulses may be one of the main barriers to their consumption (Melendrez-Ruiz, et al., 2019). In that study, French participants had to compose a dish from photographs of food items, in different scenarios. Participants chose pulses significantly more often when they were projected in a situation where they would not have to be cooked. As the study used only photographs of raw products (lentils, chickpeas, white beans, and red beans), it was not possible to infer how the consumer would behave toward processed pulse-based products. In the more recent study, an evocation task was carried out to understand the social representation of pulses among French non-vegetarian participants [START_REF] Melendrez-Ruiz | Do French Consumers Have the Same Social Representations of Pulses as Food Industry Professionals?[END_REF]. Respondents had to cite 5 words that came spontaneously to mind when they heard the word "pulses". Words related to culinary preparation were used quite frequently, and participants considered these words of great importance. This result reveals that, even when there is no reference to any form of processing in the questions asked, participants spontaneously think about preparation when they think about pulses. For French people, the association between pulses and preparation is anchored in the social representations of pulses; this association was not present among Spanish people who carried out the same task [START_REF] Melendrez-Ruiz | Enhancing assessment of social representations by comparing groups with different cultural and demographic characteristics: A case study on pulses[END_REF].

Taking into account this consumer reticence concerning the preparation of pulses, there has lately been an increase in the development of processed pulse products [START_REF] Métayer | Randomization of CATA attributes: Should attribute lists be allocated to assessors or to samples?[END_REF]. It is now possible to find, on the market, pulses with different levels and types of processing, from unprocessed to ready-to-eat. Innovative ready-to-eat pulsebased products are now available in France, which should help to overcome the difficulty of preparation considered by many as a barrier to consumption. These ready-to-eat products are often ultra-processed foods (UPFs), which means that they have undergone "excessive processing" and contain ingredients and/or additives whose primary function is to modify color, taste, and texture (Fardet, 2018a). Several classifications have been proposed to distinguish the level and type of industrial processing that a food product undergoes: NOVA [START_REF] Monteiro | A new classification of foods based on the extent and purpose of their processing[END_REF], SIGA (Fardet, 2018c), the classifications proposed by IFIC [START_REF] Eicher-Miller | Contributions of Processed Foods to Dietary Intake in the US from 2003-2008: A Report of the Food and Nutrition Science Solutions Joint Task Force of the Academy of Nutrition and Dietetics, American Society for Nutrition, Institute of Food Technologists, and International Food Information Council[END_REF], and by the University of North Carolina [START_REF] Poti | Is the degree of food processing and convenience linked with the nutritional quality of foods purchased by US households?[END_REF], etc.

Each of these classifications proposes a different number of classes and considers different grouping criteria. A common point between these classifications is that unprocessed and minimally processed foods are in the same group and are distinguished from processed foods (processes meant to preserve or precook), and ready-to-eat foods (ready-to-eat, multiingredient foods obtained by industrial processes, etc.). Pulse-based products exist at all these levels of processing: unprocessed pulses (e.g., raw lentils, beans, etc.), processed pulses (e.g., pulses cooked with water and salt, and sold in cans or glass jars, or vacuumpacked) and ready-to-eat foods containing pulses (e.g., ready-to-eat dishes, such as traditional recipes with meat and pulses, but also patties, meatballs, etc., where pulses are no longer recognizable). Because of these multiple complex classifications, the differences between processed and ready-to-eat foods may be less easily perceived by consumers. In addition, it has been shown that an increase in the consumption of UPFs was associated with a higher overall risk of cardiovascular disease [START_REF] Srour | Ultra-processed food intake and risk of cardiovascular disease: Prospective cohort study (NutriNet-Santé)[END_REF], a higher mortality risk among the adult population [START_REF] Schnabel | Association Between Ultraprocessed Food Consumption and Risk of Mortality Among Middle-aged Adults in France[END_REF], and an increase in the risk of cancer [START_REF] Fiolet | Consumption of ultra-processed foods and cancer risk: Results from NutriNet-Santé prospective cohort[END_REF]. These results have been widely communicated to consumers. The level of processing applied to pulses could be considered negatively by consumers, and it is therefore necessary to determine their mental representations of different types of pulsebased products.

French consumers know what lentils, beans, and chickpeas are, and are quite well informed about their properties (Melendrez-Ruiz, et al., 2019), but they tend to regard each type of pulses differently. As a consequence, it seems necessary, when studying French consumers' mental representations of pulses, to avoid the generic term "Pulses", and instead to use examples of pulses. The great variety of types of pulses (i.e., red lentils, green lentils, brown lentils, white beans, red beans, black beans, chickpeas, and dried peas) together with the diversity of processing applied to these pulses may make it difficult to untangle the many barriers to pulse consumption. In these conditions, studying consumers' mental representations of pulse-based products is challenging. Mental representations are defined as cognitive products and individual mental processes that come from the interaction of individuals with their environment, allowing them to code the meaning of stimuli and store this information in memory [START_REF] Gallen | Le rôle des représentations mentales dans le processus de choix, une approche pluridisciplinaire appliquée au cas des produits alimentaires[END_REF]. Traditional questionnaires have been used to study mental representations, but a questionnaire would be overly long and repetitive in the present case. Furthermore, social desirability bias is a known risk during direct questioning. Indirect methodologies, such as word associations, sentence completion, or projective techniques, have been developed to avoid this risk [START_REF] Fisher | Social desirability bias and the validity of indirect questioning[END_REF].

The main objective of the present study was to capture French consumers' mental representations of various pulse-based products with different recipes, and different levels and types of processing. We used a Check-All-That-Apply (CATA) questionnaire. Within sensory science, the CATA method is frequently used as a rapid sensory profiling technique. It consists of asking assessors to select from a list (words or phrases) all the attributes that they consider the most appropriate to describe a product [START_REF] Valentin | Quick and dirty but still pretty good: A review of new descriptive methods in food science: New descriptive methods in food science[END_REF]. In the food domain, some studies have used a CATA test with images rather than food products. For example, images have been used to characterize the expected sensory characteristics of wine presented in different bottles [START_REF] Puyares | Searching a specific bottle for Tannat wine using a check-all-that apply question and conjoint analysis[END_REF], and for apples with different internal defects [START_REF] Antúnez | Visual attention to rate-all-thatapply (RATA) questions: A case study with apple images as food stimuli[END_REF]. Such CATA tests are easy to execute for participants without any particular knowledge and do not require specific training.

Product characterization obtained from consumers using a CATA test is considered to be reliable [START_REF] Jaeger | Check-all-that-apply (CATA) responses elicited by consumers: Withinassessor reproducibility and stability of sensory product characterizations[END_REF]. Indeed, providing a list of characteristics to participants allows them to understand rapidly the perceived sensory characteristics of a variety of products. In the present study, we used the CATA questionnaire to capture how consumers characterize products, using attributes related not to sensory characteristics, but to more general characteristics, in order to access consumers' representations, beliefs, and attitudes, in relation to the products presented.

Two separate studies were carried out to achieve our objective. In the first study, we used a CATA test to measure whether and how consumers differentiate between pulsebased products with different levels of processing. Comparing the attributes selected for different products should allow us to understand the representations and beliefs about different types of pulse-based products, and thus to identify possible barriers to their consumption. In the second study, we compared the results obtained for pulses with the results obtained for vegetables, in order to determine whether the factors underlying the representations of pulse-based products were specific to pulses or could also be observed with another family of products.

Materials and methods

Our study was divided into two steps. Study 1 and Study 2 were both conducted in accordance with the Declaration of Helsinki and were approved by the ethical committee of INSERM N°18-506. Institutional Review Board INSERM (CEEI/IRB) (IRB00003888, IORG0003254, FWA00005831).

General organization for the two studies

People who agreed to take part in the two studies were asked to fill out a consent form. Then they carried out a CATA test on a computer. The study began with an explanation of the instructions. Then participants were asked to select all the attributes on the CATA list that they considered the most representative of each image presented. The image appeared at the top of the computer screen, in the center (one image at a time), and the list of attributes was listed below, in five columns. The order of presentation for the images and for the list of attributes was randomized between participants. For the same participant, the order of the list of attributes was the same for all the images, as recommended by [START_REF] Métayer | Randomization of CATA attributes: Should attribute lists be allocated to assessors or to samples?[END_REF]. At the end of CATA testing, participants filled out a short questionnaire about their age, sex, and level of education. Redjade software was used to build the test, and to collect the data. The total amount of time spent by participants was around 15 to 20 minutes, on average.

Study 1

Sample size and participants

Participants were recruited on a voluntary basis, over three weeks, at a Cultural and Social Center in Dijon, France. People attending the cultural center were approached by the experimenter, who invited them to participate in a study "about food". The real aim of the study was not revealed, to avoid potential biases during the study. The inclusion criteria were to be fluent in French, to be aged between 25 and 65, and not to have a specific, restrictive diet (e.g., vegetarian or vegan).

In total, 73 participants were recruited; their characteristics are shown in Table 1. A bootstrapping resampling approach was used to determine the stability of the samples in the perceptual space as a function of the number of consumers. For that purpose, 1000 random subsets were obtained, for 30, 43, and 73 consumers. A Correspondence Analysis was then performed on each random subset from which the first two dimensions were extracted, to compare them with the reference map (corresponding to 30, 43, or 73 consumers) via the Regression Vector (RV) coefficient.

The RV coefficient obtained from the correspondence analysis, plotted as a function of the number of consumers, considering 0.95 as the cut-off point [START_REF] Blancher | A method to investigate the stability of a sorting map[END_REF].

The higher the RV coefficient, the greater the stability of the samples in the perceptual space [START_REF] Faye | An alternative to external preference mapping based on consumer perceptive mapping[END_REF]. All three sample sizes generated stable perceptual spaces, and the results obtained are therefore valid, coherent with the recommended number of participants (60-80) for a CATA questionnaire [START_REF] Ares | Investigation of the number of consumers necessary to obtain stable sample and descriptor configurations from check-all-that-apply (CATA) questions[END_REF].

Experimental design Choice of a set of images

After field observations in French supermarkets, twelve pulse-based products were chosen. The products were selected by their main ingredient and level of processing. Three types of pulses were selected as main ingredients: lentils, white beans, and chickpeas. For each of these pulses, 4 products were chosen, according to their level of processing. Group (I) is for unprocessed, i.e., dry pulses, in their raw state. Group (II) is for processed, i.e.

canned pulses, prepared with water and salt (which can be consumed as is, or used to prepare a more complex dish). Group (III), for ready-to-eat pulses, was divided into two sub-groups. Sub-group (IIIa) is for ready-to-eat main dishes, containing pulses combined with a meat product, presented in a can. These images represent the most common way to consume pulses in France, and correspond to a well-established script: meat + accompaniment. For this reason, they will be described as "traditional -ready-to-eat" throughout this article. Sub-group (IIIb) was used for recipes that are seen as less traditional and more innovative in France, such as pulse-based "meatball substitutes". These products are stand-alone meals, in which the main ingredient (pulses) is no longer recognizable.

They will be described as "new -ready-to-eat" throughout this article (Figure 1).

The images used in Study 1 were obtained from French online supermarkets. They were chosen among many possible products to present a certain visual homogeneity (packaging format, with a limited number of colors...). For each image, the brand and all claims were erased (i.e., produced in France, rich in fiber, etc.), in order not to draw attention to specific products for reasons irrelevant to the objective of our study. The attributes used in the CATA questionnaire were collated from previous studies, based on the characteristics of pulses considered most common by French consumers [START_REF] Magrini | Pulses for Sustainability: Breaking Agriculture and Food Sectors Out of Lock-In[END_REF]Melendrez-Ruiz, et al., 2019;Melendrez-Ruiz, et al., 2019;[START_REF] Melendrez-Ruiz | Do French Consumers Have the Same Social Representations of Pulses as Food Industry Professionals?[END_REF]. A total of 28 terms was selected (Table 2).

Study 2

Sample size and participants

In Study 2, two different pools of participants voluntarily completed the CATA questionnaires online (one for vegetables and the other for pulses). Participants were recruited using snowball sampling by email, where a link was shared for over four months.

In total, 108 participants began the CATA questionnaire for pulses, but only 69 completed it. From that number, 3 participants were eliminated because they followed a vegetarian or vegan diet; thus 66 participants were included in the study (Table 3). In total, 107 participants began the CATA for vegetables, but only 81 completed it. From that number, 3 participants were eliminated because they followed a vegetarian diet. The answers from 78 participants were thus included in the analysis (Table 3). Of the participants, 82% were women and 18% were men. We also checked that participants spent a comparable amount of time on each of the two questionnaires: averaging around 15 to 20 minutes. ready-to-eat combining pulses with a meat product. For Group I, all three pulses shared the same packaging format. The pulses in both Group II and Group III were divided by packaging format into two sub-groups: a) canned, and b) frozen. Group III represents the most common way to consume pulses in France, corresponding to a well-established script: meat + accompaniment. The same recipe was presented in the two formats.

Figure 3 shows the food products used for the CATA questionnaire about vegetables.

The selection process followed the same rules, except for the canned ready-to-eat group (IIIa), which is not readily available in France. In total, twelve images were selected with three different products: spinach, zucchini, and eggplant. Each vegetable was presented at the same three levels of processing: (I) unprocessed, (II) processed, and (III) ready-to-eat.

Group I was represented by raw products; Group II (a) products were canned vegetables, cooked with water and salt (and with tomato for the eggplants). Products from Group II (b)

were frozen vegetables. Group III was represented by ready-to-eat dishes, where a vegetable product was used as the main ingredient. For each image, both the brand and all claims were erased (i.e. produced in France, rich in fiber, etc.).

Terms used for the CATA questionnaire

Of the 28 attributes used in Study 1 (Table 2), we reused 27 and discarded one (it's local). We added two attributes: it's bad for the health (c'est mauvais pour la santé) and it's eaten mostly in summer (ça se mange plutôt en été) because participants in Study 1 had mentioned that these attributes were missing from the initial list. The resulting list of 29 attributes was used for both CATA questionnaires in Study 2 (on pulse-based products, and on vegetables).

Procedure

A single link was created for both questionnaires (pulses and vegetables), and the program was set up in such a way that participants were automatically split into two groups: one out of every two participants completed the CATA questionnaire for pulses, while the next participant completed the CATA questionnaire for vegetables, and so on.

Each participant participated in only one questionnaire. Just after completing the CATA questionnaire and before answering the sociodemographic questions, participants answered the single-item Food Choice Questionnaire proposed by [START_REF] Onwezen | The development of a single-item Food Choice Questionnaire[END_REF], with a seven-point scale, from 1: "not at all important" to 7: "very important". At the end, participants filled out a short questionnaire to indicate their age, sex, level of education, whether they followed a specific diet, and their province (to check that they were living in France).

Statistical analysis

For In addition, in Study 2, we performed a t-test over the scores obtained for both groups on each factor of the single-item Food Choice Questionnaire to compare the groups of participants that completed the study for pulses and for vegetables.

The XLSTAT software program for Windows (Addinsoft, version 2020-1) was used for all statistical analyses. The confidence interval was set at 95%.

Results

Study 1

The Cochran Q test revealed that 27 out of the 28 attributes were used differently between the 12 images of pulse-based products (p-value < 0.05). The only attribute that was not used differently was "it's local". The Correspondence Analysis (CA) presented in Figure 4 shows the differences between the products. The first two axes explain 78% of the total variance. The CA shows associations between pulse-based products and attributes.

Axis 1 divides products by novelty, while Axis 2 divides products by level of processing.

Food products were divided by processing only: different pulses with the same type of processing were grouped together. All the products in Group I (raw, unprocessed products)

were in the same group, mainly characterized by the attributes: natural, good for health, good for the environment, and difficult to prepare. Products in Group II (processed) were also close to one another, and were considered to be cheap, easy to find, and traditional.

Participants identified Group IIIa, composed of all the canned (traditional ready-to-eat) products, as outdated, it gives me stomach-ache, and I don't like it. Group IIIb was composed of all the innovative (new ready-to-eat) products, and the attributes used by participants were: it's chic, it's expensive, and it's modern. The attributes selected for the two sub-groups in Group III were very different: canned (traditional ready-to-eat) products had a more negative image than the innovative (new ready-to-eat) products. This study is the first evidence that representations of pulse-based products are not the same, depending on the level of processing and the recipe. The difference between pulse-based products is driven by their processing and/or recipe, and not by the type of pulses (lentils, chickpeas, or white beans). It was not possible to draw precise conclusions about the specific influence of the level of processing from the results of Study 1. Very different attributes were associated with the two types of ready-to-eat products (traditional vs new), which suggests that the level of processing may not be the only factor influencing participants' mental representations. Considering that the packaging format and type of processing were confounding variables in this sample of products, we cannot exclude the possibility that packaging format may play a role in consumer representations of pulses. We can also question whether the negative image of traditional ready-to-eat products is more related to their recipe, to their presentation on the packaging (e.g., color and illustrations),

or their sensory properties. Study 1 highlighted a distribution of pulse-based products by level of processing. It is unclear whether the level of processing is particularly important for this specific family of food products, or if it would be also observed with other food product families.

Study 2

Study 2 aimed to overcome the limitations observed in Study 1. In order to compare two product-spaces, we used comparable CATA questionnaires to characterize pulse-based products and another food product family (vegetables). In both product-spaces, the products were selected as having either different packaging formats but the same level of processing and the same recipe, or the same packaging format but different recipes and levels of processing.

Characterization of each set of respondents according to the food choice questionnaire

Table 4 shows the mean values obtained for each factor in the single-item Food Choice Questionnaire. The Student t-test showed no significant differences for each factor between the participants who answered the CATA on pulses and the participants who answered the CATA on vegetables. Thus, both pools of participants in Study 2 were driven by similar motivations.

CATA questionnaire on pulses

The Cochran Q test revealed that 21 attributes were used differently for the images of pulse-based products (p-value < 0.05). The correspondence analysis presented in Figure 5 shows the differences between products. The first two axes explain 78% of the total variance. Axis 1 mainly divides the pulse-based products into two groups: unprocessed and processed are opposed to ready-to-eat products. Participants identified the unprocessed products (I) and the processed frozen products (IIb) as more adapted for vegetarians, better for health and for the environment, more natural and organic than the ready-to-eat products.

For the products from groups (I) and (II), participants more often selected the attribute I buy it. All the ready-to-eat products, canned (IIIa) and frozen (IIIb) were grouped together, and characterized by attributes such as it gives me stomach-ache, it's exotic, it's bad for the health, it's expensive, it's for a solo meal, it's eaten mostly in winter, it's traditional, I don't like it, I don't buy it, and it's easy to prepare. Unprocessed products (I) based on red beans or white beans were considered more difficult to prepare than unprocessed lentils, and all the processed products. By contrast, the canned processed products (IIa) were characterized as easy to prepare, easy to find, cheap, and adapted for sportsmen.

CATA questionnaire on vegetables

The results from the Cochran Q test showed that participants used 20 attributes differently across vegetable-based products (p-value < 0.05). The Correspondence Analysis (CA) presented in Figure 6 shows the differences between the vegetable-based products.

The first two axes represent 78% of the total variance. Axis 1 opposes the (raw) unprocessed (I) and processed frozen vegetables (IIb) to the canned processed (IIa) and ready-to-eat vegetables (III). The attributes used by participants to characterize all the (raw)

unprocessed products (I) and the processed frozen products (IIb) were: it's natural, it's good for the health, it's for vegetarians, and I really liked it. By contrast, the attributes more often used for the canned processed (IIa) and ready-to-eat vegetables (III) were: it's bad for health, it's for a solo meal, it gives me stomach-ache, it's outdated, I don't buy it, I don't like it, and I don't know it.

Axis 2 opposes raw eggplant and zucchini, associated with the attributes: it's organic, it's expensive, and it's eaten mostly in summer, to frozen spinach, considered as cheaper than the other products. (III) to ready-to-eat frozen.

General discussion

The main objective of this study was to capture consumers' mental representations of pulses with different levels of processing, using a Check-All-That-Apply (CATA) questionnaire. We used the results of two studies to verify if the level of processing affected consumers' representations of pulses. Study 1 highlighted new questions and we carried out Study 2 to check (i) if the different levels of processing were perceived similarly for two groups of food products; (ii) if the differences in representations between products depended only on their level of processing, or also on the type of recipe or packaging format.

Does the level of processing affect mental representations, attitudes, and beliefs about products?

One of our main findings from both Study 1 and Study 2 is that the differences in representations, attitudes, and beliefs between various food products that belong to the same food group (pulses or vegetables) are driven by their level of processing (unprocessed, processed, or ready-to-eat), rather than by the fact that they contain the same raw product (e.g. lentils, eggplant, beans, etc.).

Although not all the products included in Studies 1 and 2 were the same, and although each study was carried out with different participants, the results from both studies show similar tendencies. The descriptors used by participants reveal a more positive attitude and beliefs toward products in their raw, unprocessed state, and in a processed state, whatever their packaging format (cans or bags). By contrast, participants often associated ready-to-eat pulses, whether canned and frozen, with attributes that reveal a negative attitude and beliefs (outdated, it gives me stomach-ache, I don't like it, and it's bad for the health). Our results are in accordance with a study carried out by the European Food Information Council, in which UK residents showed a preference for unprocessed foods, and perceived processed food negatively, arguing that there was a loss of nutritional and health benefits in these products [START_REF] Eufic | Understanding perceptions of processed food among UK consumers. A qualitative consumer study by EUFIC[END_REF]. In a previous study, we observed that French non-vegetarian participants considered pulses as particularly difficult to cook, compared to products from other food groups (Melendrez-Ruiz, et al., 2019). The results from these two studies highlight a paradox. On the one hand, people who consider pulses as difficult to cook may rarely prepare homemade dishes with raw pulses. On the other hand, people who consider ready-to-eat pulse-based products negatively will probably not consume them frequently. These two perceived properties of pulses may therefore explain the low consumption of pulses by non-vegetarian French people. Yet the negative attitude about ready-to-eat foods could be specific to the profile of the participants in our study. For example, French vegetarian and vegan people tend to consume ultra-processed plant-based meat and dairy substitutes to avoid animal-based products, and it has been observed that their diet is richer in UPFs than that of meat-eaters or pesco-vegetarians [START_REF] Gehring | Consumption of Ultra-Processed Foods by Pesco-Vegetarians, Vegetarians, and Vegans: Associations with Duration and Age at Diet Initiation[END_REF]. To confirm such results, it would be necessary for further study, to compare consumers with different diets and/or socio-economic characteristics, to determine if mental representations toward pulse products vary across different groups.

Are mental representations of processed products the same for different food groups?

Study 2 allowed us to compare pulse-based products and vegetable-based products. As participants for both the CATA questionnaires had similar characteristics, it was possible to compare results, to underline the common points and differences between pulse and vegetable products. As already observed for pulse-based products, results for unprocessed and ready-to-eat vegetable-based products were in direct opposition. Another similarity was that unprocessed and processed frozen vegetables were characterized by attributes that revealed a positive attitude and beliefs (e.g. it's organic, it's natural, it's good for the health, and I like it) while the ready-to-eat frozen vegetables were characterized with attributes that reveal a barrier to consumption (e.g. it's bad for the health, and it's expensive). Nevertheless, we also found differences between the two groups of products.

Participants used similar attributes for processed canned vegetables and for ready-to-eat vegetables. For pulses, processed products were characterized by attributes also used for unprocessed products. Canned processed pulses have a positive image, while canned processed vegetables have a negative image. This could explain buying behavior in France:

French adults declare that they most often buy canned pulse products (92%, ANSES, 2017).

By contrast, vegetables are mostly bought fresh (71%), and less often processed (29%), whether canned or frozen [START_REF] Unilet | Suivi du marché des légumes en conserve et surgelés en restauration en France[END_REF]. This observation suggests that French people are more familiar with canned pulses than with raw pulses, but with raw vegetables rather than with canned vegetables. Their mental representations of canned pulses may thus be better anchored than those for unprocessed pulses. There may also be a negative image of canned vegetables in general, as revealed by a Swiss study showing that canned green beans were perceived by participants to be harmful for the environment [START_REF] Tobler | Organic Tomatoes Versus Canned Beans: How Do Consumers Assess the Environmental Friendliness of Vegetables?[END_REF]. Our hypothesis to explain our result is that French people, who are more used to eating canned pulses, tend to consider this level of processing as the minimum required to overcome the difficulty of preparation. Our results highlight that the mental representations of products resulting from an industrial process are not perceived in the same way, depending on the food group to which they belong. Mental representations seem to depend on consumers' familiarity with products.

Three key points for mental representations of pulse-based products: the recipe, the level of processing, and the packaging format

Among the main results of Study 1 are the differences in representations and beliefs between traditional and new ready-to-eat products in France. Traditional ready-to-eat products were mostly characterized by attributes such as outdated, it gives me stomachache, I don't like it, that can be considered as a barrier to consumption. New ready-to-eat products were characterized by very different attributes (e.g. chic, modern, etc.) that revealed a positive attitude. This is in line with the literature showing that more innovative ultra-processed foods were considered to have an image of "good for the health", especially for vegetarians and vegans [START_REF] Fardet | Mangeons vrai: Halte aux aliments ultra transformés ! Fardet, A. (2018a). Characterization of the Degree of Food Processing in Relation With Its Health Potential and Effects[END_REF]. Such differences in the representation of traditional and innovative ready-to-eat foods could be related either to the recipe or to the presentation and packaging format of the product. Traditional products contain whole pulses that are recognizable to consumers, unlike meatball substitutes, where pulses are mashed and mixed with other ingredients. As a consequence, consumers may find it hard to distinguish pulses in the product. In addition, even though we eliminated all claims and brands, the packaging of the innovating ready-to-eat products used in our study contained images of unprocessed products (versus cooked products in traditional recipes). The participants in our study may have perceived the image of unprocessed pulses as more natural. As shown by [START_REF] Devia | References to homemade and natural foods on the labels of ultra-processed products increase healthfulness perception and purchase intention: Insights for policy making[END_REF], the images of natural food on the labels of ultraprocessed products can have a positive effect on consumer perception, creating a belief that a product is healthful, and thus having a positive effect on purchasing intention. To disentangle whether the negative image of traditional ready-to-eat pulse-based products was related to packaging or only dependent on the recipe, the products presented in Study 2 were all traditional recipes.

For each type of pulses, the same recipe was presented under two packaging formats: frozen products and canned products. We found that consumers had quite negative mental representations about both groups of ready-to-eat products (canned and frozen), which apply to the product itself (the recipe) and not the packaging format. Consumers also have a positive mental representation of the two processed pulse-based products with the same recipe, whether frozen or canned.

How to overcome the barriers to consumption of pulses

Beside being considered as natural, good for the health, and for the environment, the unprocessed pulses in our study were also characterized as difficult to prepare. These findings confirm the results of a previous study on raw pulses for non-vegetarian French consumers, based on a questionnaire (Melendrez-Ruiz, et al., 2019). Participants characterized pulses with little processing, presented in a metal can, as cheap, and easy to find, which reflects the French market reality. Canned pulses and ready-to-eat pulse products shared the perceived characteristic of being easy to prepare. Generally speaking, we observed a dichotomy between unprocessed products that have a positive image but are considered difficult to prepare, and ready-to-eat products that have a more negative image but are considered easy to prepare. This could be one of the main barriers to pulse consumption.

One of the levers to encourage pulse consumption could be to enhance the attractiveness of traditional processed products, and increase the availability of frozen products. Participants identified frozen pulse-based products with little processing as: for vegetarians, and I do buy it. This result could indicate new interest in frozen products among French consumers, even if the pulses mainly consumed in France are canned [START_REF] Champ | Les légumineuses pour l'alimentation humaine: Apport nutritionnels et effets santé, usages et perspectives[END_REF].

New recipes for pulse-based ready-to-eat foods also seem to be an interesting opportunity to increase pulse consumption. Products presented in the form of "meatballs"

were related in our study to attributes like: chic, modern, but also expensive. It seems that these innovative products do not suffer from a negative image among French consumers.

This could be explained by their novelty on the market, which makes them more attractive than traditional pulse-based products. Yet it is important to highlight that some of these ready-to-eat products can be classified as ultra-processed (e.g., additives, excessive processing, high fat, sugar, and salt content) which may be consumed in small quantities and limited to a maximum of 15% of the daily calorie intake [START_REF] Fardet | Mangeons vrai: Halte aux aliments ultra transformés ! Fardet, A. (2018a). Characterization of the Degree of Food Processing in Relation With Its Health Potential and Effects[END_REF][START_REF] Fardet | La classification NOVA des aliments selon leur degré de transformation: Définition, impacts santé et applications. 31. Fardet, A[END_REF]. The same ready-to-eat product from two different brands may have two completely different compositions. Some of these products contain a large list of ingredients and additives, and would be classified as ultra-processed, while others only contain a small number of ingredients and very few or no additives. Research and development should focus on creating new pulse-based products, that are ready-to-eat, combining pulses with other ingredients (mostly cereals), not containing any additives or artificial flavors, and with a good nutritional profile.

Finally, supplementary studies will be necessary to investigate whether the level of processing of a pulse product would influence real-life consumer food choices in a retail environment. As shown in the current study, French participants may have positive and/or negative mental representations about a pulse-based product because of its level of processing, but this does not necessarily mean that this product would not be chosen when consumers are in a real-life buying context. Successfully targeted communication about pulse-based foods can be a key element to highlight the positive features of these products.

Conclusions

Our results show that the industrial processing that a food product undergoes will affect consumers' mental representations. The use of the Check-All-That-Apply (CATA) tests showed that pulse-based products are distinguished according to their processing, and not by the type of pulses they contain. Whether in unprocessed state, processed (canned and frozen), or new ready-to-eat products, pulses had a positive image. By contrast, pulse products classified as traditional ready-to-eat (canned or frozen) were associated with a more negative image. The study also indicated that positive or negative representations, beliefs, and attitudes are related to the pulse-based product itself rather than to its packaging. Our study allowed us to identify a major barrier to the consumption of pulses in France. Indeed, French people consider pulses as products that are difficult to cook, yet have quite a negative attitude toward traditional ready-to-eat pulse-based products. Overall, the results of the present study highlight some levers that could be used by the pulse supply chain to increase pulse consumption. These levers are the development of new ready-to-eat pulse-based products, combining nutritional quality with an innovative image.

Figure 1 .

 1 Figure 1. Images of pulse-based products used in the CATA questionnaire for Study 1, sorted by level of processing and type of pulses

Figure 2 .

 2 Figure 2. Images used in the CATA questionnaire on pulse products for Study 2. Dotted lines indicate products also used for Study 1.

Figure 3 .

 3 Figure 3. Images used in the CATA questionnaire on vegetable products for Study 2.

Figure 4 .

 4 Figure 4. Correspondence Analysis (CA) for the CATA questionnaire on pulses in Study 1. Products (I) correspond to raw, unprocessed, (II) to processed, (IIIa) to traditional ready-to-eat and (IIIb) to new ready-to-eat.

Figure 5 .

 5 Figure 5. Correspondence Analysis (CA) for CATA on pulses in Study 2. Products (I) correspond to raw, unprocessed, (IIa) to processed canned, (IIb) to processed frozen, (IIIa) to ready-to-eat canned and (IIIb) to ready-to-eat frozen.

Figure 6 .

 6 Figure 6. Correspondence Analysis (CA) for the CATA on vegetables. Products (I) correspond to raw, unprocessed, (IIa) to processed canned, (IIb) to processed frozen, and

Table 1 .

 1 Characteristics of participants

	Age Women Men Total
	25-34	17	5	22
	35-44	20	11	31
	45-54	7	3	10
	55-64	9	1	10
	Total	53	20	73

Table 2 .

 2 List of attributes used in the CATA questionnaire for Study 1

	I. Unprocessed	II. Processed	IIIa. Traditional -
			Ready-
		List of attributes

to-eat IIIb. New - Ready-to-eat Green Lentils Chickpeas White beans

	It's for a solo	It's chic	I buy it	It's easy to find	It's organic
	meal	(C'est chic)	(Je l'achète)	(C'est facile à	(C'est bio)
	(C'est pour un repas			trouver)
	en solo/ seul)
	It's for a	I don't like it	I don't buy it	It's hard to find	I don't know
	convivial meal	(Je n'aime pas)	(Je ne l'achète	(C'est difficile à	it
	(C'est pour un repas		pas)	trouver)	(Je ne le connais
	convivial)				pas)
	It's eaten mostly	I really like it	It's exotic	It's for	It's natural
	in winter	(J'aime beaucoup)	(C'est exotique)	vegetarians	(C'est naturel)
	(Ça se mange plutôt			(C'est pour les
	en hiver)			végétariens)
	It's traditional	It's good for the	It's local	It's for	It gives me
	(C'est traditionnel)	environment	(C'est local)	sportsmen	stomach-ache
		(C'est bon pour		(C'est pour les	(Ça me donne
		l'environnement)		sportifs)	mal au ventre)
	It's modern	It's cheap	It's difficult	It's good for the	It's trendy
	(C'est moderne)	(Ce n'est pas cher)	to prepare	health	(C'est tendance)
			(C'est difficile à	(C'est bon pour la
			préparer)	santé)
	It's expensive	It's easy to prepare	It's outdated
	(C'est cher)	(C'est facile à
		préparer)

(C'est vieillot)

Table 3 .

 3 Characteristics of participants who answered the CATA questionnaire about pulses or vegetables.Different food images were chosen for each CATA questionnaire. For the CATA questionnaire about pulses (Figure2), fifteen products were selected, to represent 3 types of pulses, with different levels of processing. Two of the three types of pulses were the same as in Study 1 (lentils and white beans), but red beans replaced chickpeas because only a

		CATA Pulses		CATA Vegetables
	Age	Women	Men Total	Women	Men	Total
	18-24	15	3	18	13	6	19

limited number of processed chickpea products is available in French supermarkets. For each type of pulses, three levels of processing were selected: (I) unprocessed, consisting of raw dried pulses; (II) processed, consisting of pulses cooked with water and salt; and (III)

Table 4 .

 4 Mean values obtained for each factor of the Single-Item Food Choice

	Questionnaire

characteristics

A Chi-square test was carried out for age, sex, and level of education between participants who answered the CATA on pulses and those who answered the CATA on vegetables. The results did not show any significant differences for age (p-value= 0.821), sex (p-value= 0.971), or level of education (p-value= 0.591). Participants from each group had similar personal characteristics.

Funding: This work was supported by the Carnot institute Qualiment® Acknowledgments: The authors warmly thank MJC Maladiere, and Carmela Chateau-Smith is particularly acknowledged for English proofreading.

Communication on their good-for-health properties would probably improve the perception of such products. Enhancing the attractiveness of canned processed pulses and improving the availability of processed frozen products in French supermarkets could also be a way to increase pulse consumption.

Conflicts of Interest:

The authors have no conflict of interest to disclose.

Data availability:

The lead author has full access to the data reported in the manuscript.