Consumer Satisfaction with the Quality and Availability of Gluten-Free Products

Abstract

The aim of this study is to investigate consumer attitudes toward the quality and availability of gluten-free products. For this purpose, quantitative research was conducted using a questionnaire completed by 107 respondents who consumed gluten-free products. The results of the research showed that most consumers prepared their own meals, paid attention to ingredients, and strictly adhered to a gluten-free diet. About 10% of the respondents declared that they occasionally did not follow a gluten-free diet. Respondents were generally not satisfied with the price and availability of gluten-free products on the market. An additional aggravating circumstance for them when eating out was that restaurants generally do not have a sufficient selection of gluten-free dishes in their daily offer. Although most of them stated that they buy basic, well-known gluten-free products, they want to try new products with different, new flavors. This demand offers food manufacturers the opportunity to capitalize on the rapidly growing gluten-free market by developing creative and sustainable products that not only meet dietary requirements but also exceed consumer expectations. By focusing on innovation and variety, companies can participate in a profitable market while contributing to the growth of a more sustainable economy. The results of this study pointed to consumer preferences that could be used to influence the improvement and development of new gluten-free products, which are on the rise and will have a better nutritional quality and thus had a positive impact on health.

1. Introduction

Celiac disease or gluten enteropathy is a chronic autoimmune disease caused by gluten in people with a genetic predisposition and is characterized by lifelong gluten intolerance [1]. In addition to celiac disease, other autoimmune diseases can also occur, and the frequency of malignant diseases of the digestive system is increased in patients with celiac disease compared to the general population [2]. Gluten, in addition to the fact that it can lead to the development of celiac disease in genetically predisposed individuals, can also cause a whole series of other different disorders. These gluten-related disorders are divided into three basic forms: IgE immune-mediated (wheat allergy), T-cell immune-mediated (autoimmune disorder of celiac disease) and probably multifactorial innate immune-mediated non-celiac gluten sensitivity, also called non-celiac wheat allergy (NCWS) [3,4].

The pathogenesis of NCWS is likely to be multifactorial, with the innate immune response playing a key role. Several studies have identified an altered expression of innate immune components in response to wheat consumption in heterogeneous cohorts of wheat sensitive individuals, including mucosal Toll-like receptor 2 (TLR2), PBMC-derived interleukin-10 (IL-10), granulocyte-colony stimulating factor (GCSF), transforming growth factor-α (TGF-α), and the chemokine CXCL-10 [5].

The exact identity of the molecular triggers responsible for the associated symptoms is not entirely clear yet. Besides gluten, other components have been suggested to contribute to symptoms, including additional proteins, such as α-amylase/protease inhibitors, and short-chain carbohydrates that are poorly absorbed in the small intestine, such as fructan. Recent research has identified a biological basis for the condition, with the presence of systemic immune activation in response to microbial translocation that appears to be linked to intestinal barrier defects in affected individuals.

It is believed that improving the life quality of people with sensitivity to gluten can be achieved through early diagnosis, the increased availability of gluten-free foods, improved food labeling, better dietary guidelines, and the education of doctors and dieticians about celiac disease [6]. The gluten-free diet has been known since 1941 [7]. Regardless of significant scientific progress in understanding celiac disease and preventing or treating its manifestation, a strict gluten-free diet is to date the only effective way to its treatment [8]. Maintaining a gluten-free diet results in lifestyle changes (food shopping, working conditions, travel, and meals outside the home). The frequency of celiac disease in the Western world is from 0.8% to 2.67%, and recent studies indicate that it is almost equally prevalent in developing countries (the Middle East, North Africa, South and East Asia and Latin America) [9,10].

In addition to patients with gluten-related disorders, more and more people who do not have a diagnosed gluten intolerance are practicing a gluten-free diet [11], which has led to an increase in the consumption and demand of gluten-free products. Markets and Markets [12] estimated that the size of the global gluten-free market was USD 5.6 billion in 2020 and is forecast to reach USD 8.3 billion by 2025, with a CAGR of 8.1%. The market is driven by the increasing prevalence of celiac disease and the growing population switching to a healthier way of eating. According to market research in the USA, as many as 6% of consumers use products labeled “gluten-free” every day. The results of the research by Dunn et al. [13] indicate the fact that 31% of respondents believe that avoiding the consumption of products with gluten promotes general health, while 37% believe that gluten-free products are healthier than their conventional equivalent products on the market.

Food manufacturers, as an important factor in creating the attitude of consumers and their eating habits, are increasingly directed towards the production of gluten-free products and placing on the market products bearing the label gluten-free or with a reduced gluten content [14]. In response to these challenges, numerous studies are being conducted to reduce the gluten content in wheat using new technologies such as proteolysis and the release of gliadin peptides and their modifications [15]. The label “gluten-free” can be used for food if the gluten content is less than 20 mg/kg. The label “very low gluten content” is allowed for food that consists of or contains one or more ingredient produced from wheat, rye, barley, oats, or their hybrid species, which have been specially processed with the aim to reduce the amount of gluten and does not contain gluten higher than 100 mg/kg in the final product [16]. Such labeling of products obliges the manufacturer to ensure that the food is produced and controlled in accordance with the regulations governing this area, which ensures a high level of consumer protection. Numerous surveys have shown that different eating habits and different lifestyles of consumers largely depend on their perception of the meaning of healthy food [17,18,19]. In addition to harmonizing gluten-free products with the applicable legal legislation of each individual market [20], producers, to be competitive on the market and follow new trends in food production, need feedback on the acceptability of such products from the consumers themselves.

Therefore, the goal of this research was to determine whether the gluten-free products available on the Croatian market meet the needs of consumers to determine to what extent their expectations were met regarding the selection and quality of them to provide the food industry with a better insight into this issue and enable further steps into new trends in product development.

2. Materials and Methods

Participants: 107 people in the Republic of Croatia who practice a gluten-free diet for health reasons (with or without the clinical diagnosis of gluten intolerance) was participated in the survey.

The research was conducted using an online questionnaire by sending an invitation letter with a link to the online questionnaire using e-mail and social media. There was no adjustment for age, gender, or the region from which the respondents came. The questionnaire consisted of 21 statements (questions) to which the respondents had to mark their agreement with a number from 1 to 5. In these interval scales, the value 1 indicated that the respondent did not agree with the statement at all, while the value 5 indicated that he/she completely agreed with the statement.

The questionnaire consisted of questions/statements that were divided into five groups:

• Demographic data;
• Consumer habits;
• Buying habits;
• Sources of information;
• Food labeling.

Non-linear regression analysis was performed to model the relationships using Statistica 12 (Statsoft; Tulsa, OK, USA). The models were fitted using a polynomial approach. Confidence intervals were generated for the fitted curve to assess the uncertainty in the predictions. The solid red line on graphs represents the best fit model, while the dashed red lines indicate the 95% confidence intervals around the prediction.

3. Results and Discussion

The results of the research on the consumption of gluten-free food carried out by an online questionnaire, presented in this paper, provide an insight into consumer habits and the availability of information on the gluten-free diet of the population in the Republic of Croatia.

3.1. Demographic Data

The online questionnaire was filled out by 107 people (90 women and 17 men) (Figure 1). The largest percentage of respondents (57%) were aged 31–51, while there were only three respondents over 50+, which made up 2.8% of the entire sample (Figure 2). The respondents live in the territory of eight counties, of which the most represented respondents are from continental part of Croatia. Most of respondents are from urban areas (91.3%), and of that, 38.4% live in the capital city. Alencar et al. [21] had a similar sample of respondents in their research on consumer opinion on gluten-free products. The participants in their research were mostly women (91.2%), aged 41 to 50 with a university education (45.4%).

In the sample, 63.6% of respondents have a university education (diploma or bachelor’s degree), 29.9% have a high school education and 6.5% completed elementary (or primary) education only (Figure 3). The level of education is an important predictive factor when analyzing adherence to a gluten-free diet. Previous research points to the fact that consumers with a higher level of education have a higher rate of adherence to a gluten-free diet [22].

3.2. Consumption Habits and Purchasing Behavior

The survey results showed that gluten-free food is consumed by people who have been clinically proven to have to avoid gluten-containing food (72.9%), while 27.1% of respondents, who had no sensitivity to gluten, declared that they felt better when consuming gluten-free food.

Zarkadas et al. [6] found in their research that 90% of respondents reported that they were on a gluten-free diet. In this research, people said that they had been diagnosed with gluten sensitivity after the onset of symptoms and a targeted medical examination (52.4%), while 27.4% of them answered that gluten sensitivity was accidentally discovered during the examination, along with other diseases. Most of the respondents started a gluten-free diet in adulthood (65%) and have no other dietary restrictions, except for 14% of respondents who do not consume products with lactose. The results of the conducted research showed that consumers prepare their own meals, pay attention to ingredients, and strictly adhere to a gluten-free diet. The gluten-free diet is sometimes interrupted for about 10% of respondents, which is consistent with the results of Alencar et al. [21], who found that 12.7% of respondents rarely consume gluten unintentionally. The majority (65%) prepare the same dietary food for their family as for themselves, while the others prepare two types of meals: gluten-free and traditional (

Table 1. Consumption habits.

	Average Grade (1–5)
I prepare the food myself, so I always pay attention to the ingredients.	4.50
I prepare the same diet food for my family as I do for myself, because maintaining this diet is very demanding.	3.78
There are two types of food preparation in my family: gluten-free and traditional.	3.09
I strictly adhere to a gluten-free diet.	4.47
Sometimes I stop the diet because it’s too expensive.	1.56
Sometimes I stop the diet because it takes too much time.	1.59
Sometimes I stop the diet because it’s not tasty enough.	1.37
Sometimes I interrupt my diet because it’s hard to find gluten-free food.	1.56
Sometimes I stop the diet because I haven’t experienced any negative consequences.	1.44

1—do not agree at all; 2—partially disagree; 3—neither agree nor disagree; 4—agree; 5—completely agree.

).

The intersection of dining out and sustainability is both a challenge and an opportunity for consumers and the foodservice industry. As consumers increasingly look for gluten-free options when dining out, restaurants are faced with the task of meeting diverse dietary needs while promoting sustainable practices. While dining out offers convenience and socialization, it often presents a challenge for individuals following a gluten-free diet. Many restaurants struggle to offer enough gluten-free options on their menus, leading to frustration and a limited choice for consumers. This not only impacts customer satisfaction but also highlights broader issues of inclusion and accessibility in the foodservice industry. However, addressing these challenges provides an opportunity for restaurants to embrace the principles of sustainability and improve their offering. By sourcing locally grown ingredients, reducing food waste and investing in gluten-free training for staff, restaurants can demonstrate their commitment to sustainability and customer satisfaction. In addition, by expanding their gluten-free menu options and clearly labeling dishes, restaurants can appeal to a broader customer base and promote a more inclusive dining experience for all. Furthermore, educating both consumers and restaurant staff on the importance of sustainability and gluten-free practices can lead to positive behavioral changes and a more environmentally conscious dining culture. By working together to promote sustainability and address diverse dietary needs, the food service industry can play an important role in promoting a more sustainable and inclusive economy.

The price and availability of products, on the one hand, and the lack of knowledge and information, on the other hand, proved to be the main obstacles in maintaining a gluten-free diet. Most of the respondents (60%) believe that the price of gluten-free products is one of the main problems in maintaining a gluten-free diet and it represents a significant financial burden for them (

Table 2. Factors that make it difficult to maintain a gluten-free diet.

	Average Grade (1–5)
Product selection	3.51
Product taste	3.23
Product price	1.66
Lack of self-discipline	4.16
Lifestyle (stress, overload, lack of time)	3.40
Lack of knowledge on the product	3.63
Product availability	2.28
I don’t trust the list of ingredients on the product	3.09
Lack of preparedness and knowledge of catering facilities	1.70
Lack of public awareness and information	1.90

1—significant problem; 2—quite a problem; 3—both is and is not a problem; 4—not a problem; 5—not a problem at all.

).

The study by Meydanlıoğlu and Köse [23] aimed to compare gluten-containing and gluten-free foods as the latter are generally associated with a loss of quality and taste as well as higher costs. Using a descriptive–comparative approach, 64 gluten-free products and their gluten-containing counterparts in the same categories were randomly selected from large supermarkets in Antalya. The results showed that 50% of the products analyzed were gluten-free, with bread and bakery products accounting for the largest share at 31.3%. The average price of gluten-free products was significantly higher than that of gluten-containing products. Another study also suggests that gluten-free products can be up to 85% more expensive than their gluten-containing counterparts, according to an extensive dataset of US baked goods. This comprehensive analysis of prices spans the period from 2013 to 2022 and provides a thorough examination of the cost differences between gluten-free and gluten-containing products [24]. Product availability is also one of the reasons for non-compliance with the diet. In a study conducted by Do Nascimento et al. [25], 71% of the participants indicated that they had difficulty in finding gluten-free products. A recent research study points to the fact that an inadequate understanding of nutrition can not only lead to the unintentional consumption of food products with gluten but also to the unnecessary excessive restriction of certain foods, which then has a negative impact on the overall diet [26]. Namely, by eliminating foods that do not contain gluten, the variety of food consumed also decreases, which further increases the risk of consuming a nutritionally inadequate diet [27]. People with celiac disease who consume food products that do not contain gluten (of wheat, rye, barley, and oat) have an increased risk of an insufficient intake of certain substances (iron, folates, niacin, riboflavin, calcium, and dietary fiber) compared to people who consume equivalent food products that contain gluten [28,29,30,31]. On the other hand, larger amounts of fat, sugar and flavor enhancers are added to gluten-free products to make their textural and sensory characteristics comparable to conventional products, which leads to an imbalance of nutritional and energy intake. Furthermore, the results of this research indicate that maintaining a gluten-free diet is very demanding, but it does not significantly affect the respondents’ normal life, socializing and consumption of food outside the home (

Table 3. Influence of gluten-free diet on the life quality.

	Average Grade (1–5)
I live a normal life; diet is not difficult for me to follow at home	3.61
I am particularly burdened by socializing, eating outside the home.	3.96
Socializing, eating outside the home burden me both physically and mentally.	2.53
Socializing, eating outside the home is burdensome both in lifestyle and financially.	2.41
Meal planning takes a lot of time	3.08
Procuring food takes a lot of time.	3,28
I must constantly inform myself about gluten-free diet, what was exhausting.	3.16

1—do not agree at all; 2—partially disagree; 3—neither agree nor disagree; 4—agree; 5—completely agree.

).

Based on the results shown in

Table 4. Behavior in purchasing gluten-free products.

	Average Grade (1–5)
I always buy gluten-free food at the same place.	2.69
I buy gluten-free food in specialized stores (e.g., health food stores).	2.85
I always buy gluten-free food in the place I happen to be.	3.22
I always buy gluten-free food where it’s cheaper.	3.53
I always buy well-known, standard products.	3.63
I stick to a well-known brand.	3.40
I am willing to try new flavors, new products.	4.32
I prefer homemade gluten-free products.	3.47

1—do not agree at all; 2—partially disagree; 3—neither agree nor disagree; 4—agree; 5—completely agree.

, respondents are willing to try new flavors and new products. Although price has previously been highlighted as a limiting factor in the gluten-free diet, when choosing gluten-free food, they do not necessarily choose cheaper, standard products. There is also no clear decision regarding the choice of homemade products and those from specialized health food stores and well-known producers and brands. It could be concluded that for gluten-free consumers, the criteria for choosing food are arranged somewhat differently compared to consumers of “standard” food for whom local, well-known producers and well-known brands, in addition to price, are very important when making a purchase decision. The reason for this is probably the limited offer and options for choosing gluten-free products on the market due to which other criteria fall into the background.

Respondents are mostly dissatisfied with the availability of certain types of gluten-free products on the market (

Table 5. Satisfaction with the current offer of gluten-free products on the market.

	Average Grade (1–5)
Bread	2.88
Bagel	2.27
Flour, flour mixtures	3.36
Pasta	3.50
Powder mixtures	2.54
Ready-to eat confectionery products	1.97
Sweets, biscuits	2.72
Breakfast cereals, muesli	2.72
Salty snacks	2.70
Soups, sauces	2.07
Instant products	1.96
Frozen ready meals	1.74
Spices	2.78
Dairy products	3.24
Meat products	3.23
Alcoholic beverages	2.48
Ready to eat meals (need to be heated)	1.53

0—not familiar with this group of products; 1—not satisfied at all; 2—not satisfied; 3—neither satisfied nor dissatisfied; 4—quite satisfied; 5—completely satisfied.

). They were moderately satisfied with the offer of gluten-free pasta, flour and flour mixes. When asked what type of gluten-free food they would like to buy or consume, which is not currently on the shelves of gluten-free food stores, a whole range of different products were listed and they consider to be the least available ready-to-eat and frozen meals and confectionery, instant products, soup, sauces, and bagels. For manufacturers of these product categories, it could be an opportunity to develop new products that will meet the needs of the population that is on a gluten-free diet.

Singh and Whelan [32] investigated the availability and the price of 20 different gluten-free foods in 30 different stores. They found that the availability of gluten-free food is limited and that the price of gluten-free products is much higher than the non-gluten-free ones. Across all stores, on average, only 8 (41%) of the 20 foods were available in a gluten-free version, and the price of the gluten-free version of the product was much more expensive than the same product with gluten. According to Missbach et al. [33], average gluten-free products are significantly more expensive, from +205% to +267% compared to similar products containing gluten.

In this research, respondents are not satisfied with the current price of gluten-free products on the market since gluten-free foods are more expensive than those containing gluten (

Table 6. Satisfaction with the price of gluten-free products on the market.

	Average Grade (1–5)
Bread	1.86
Bagel	1.71
Flour, flour mixtures	1.96
Pasta	2.29
Powder mixtures	1.95
Ready-to eat confectionery products	1.59
Sweets, biscuits	1.82
Breakfast cereals, muesli	1.89
Salty snacks	1.93
Soups, sauces	1.68
Instant products	1.58
Frozen ready-to eat meals	1.46
Spices	2.31
Dairy products	2.60
Meat products	2.48
Alcoholic beverages	2.16
Ready to eat meals (need to be heated)	1.33

0—not familiar with this group of products; 1—not satisfied at all; 2—not satisfied; 3—neither satisfied nor dissatisfied; 4—quite satisfied; 5—completely satisfied.

).

The dependence of the product price on product availability is shown in Figure 4. The regression analysis presented in Figure 4 indicates a positive correlation, showing that as the availability of a certain group of gluten-free products increases, their price tends to rise. Notably, the confidence intervals widen at higher levels of availability, suggesting greater uncertainty or variability in pricing as availability increases. This trend might reflect the complexities of the market dynamics for gluten-free products, where increased availability could lead to diverse pricing strategies, possibly influenced by factors such as consumer demand, production costs, and market competition. As availability increases, this could indicate that the market is expanding beyond niche consumer groups to a broader audience, allowing producers to charge premium prices. Consumers may perceive greater availability as an assurance of quality or specialty status, justifying higher prices. Additionally, the higher prices could be due to the increased costs associated with ensuring the gluten-free status of products, which may include specialized production processes, the sourcing of certified ingredients, and rigorous testing, all of which contribute to higher prices, even as availability grows. The observed relationship highlights the need for the careful consideration of availability in pricing strategies to ensure market competitiveness while meeting consumer needs.

The perceived quality of food that can be consumed in a gluten-free diet according to the respondents’ perception is not adequate. The obtained results are in accordance with the literature data, according to which the functional and organoleptic properties of gluten-free products are often still worse than those containing products with gluten [34]. Traditionally, most gluten-free products are made from gluten-free flour (rice and corn flour) with the addition of native and modified starches mixed with different hydrocolloids due to their influence on structure and water binding. Montemurro et al. [5] stated the alternative raw materials (pseudocereals—amaranth, quinoa and buckwheat; legumes—chickpeas, lentils, beans, peas and soybeans) and the application of new technologies could be included in order to improve the quality, durability and acceptability of gluten-free products.

The dependence of perceived quality (organoleptic properties) on satisfaction with product price is shown in Figure 5. The non-linear regression analysis with confidence intervals presented in Figure 5 illustrates the relationship between perceived quality, measured through organoleptic properties, and consumer satisfaction with product price. The central solid line represents the main trend, indicating a positive correlation: as perceived quality increases, so does satisfaction with the price. The dashed lines around the main trend represent confidence intervals, suggesting a range of variability in this relationship. The widening of these intervals at higher levels of quality implies increasing uncertainty or variability in consumer satisfaction as the quality improves. This pattern may suggest that while a higher quality of gluten-free products generally leads to better sensory properties and greater satisfaction, individual consumer responses can vary more widely, possibly due to differing expectations or price sensitivity. This finding underscores the importance of balancing quality enhancements with price adjustments to maximize consumer satisfaction.

3.3. Sources of Information

The respondents declared that the most common sources of information regarding the gluten-free diet were educational measures about celiac disease, “patient educations” (28%), food labels (23%), information from a doctor (17%) and the Internet (13%) (

Table 7. Sources of information regarding the gluten-free diet.

	%
Educational measures on celiac disease “patient education”	28
Educational publications, books about celiac disease	3
Information from my doctor about my sensitivity to celiac disease	17
From Dietitian	1
From Other patients	3
From Friends, acquaintances, colleagues, neighbors	2
Newspaper articles	2
Website of the National Celiac Association	6
Brochures distributed by the manufacturer	1
Internet	13
Television	1
Radio	0
Food label	23

). In addition to the offered sources of information that were listed in the questionnaire, the respondents stated that they preferred to use information from local associations of patients and a Facebook groups of patients with their experiences.

Zarkadas et al. [6] found in their research that respondents received the best information about celiac disease and its treatment from the Canadian Celiac Association (CCA) (64%), gastroenterologists (28%), dieticians (26%) and family doctors (12%). According to research by Silvester et al. [26], books (cookbooks), the Internet, print media, associations of patients and people with celiac disease were the most frequently used sources of information about gluten-free nutrition.

Adopting regulations that list the mandatory labeling of allergenic and intolerant ingredients of gluten certainly made it easier to choose appropriate food for those on a gluten-free diet [16]. The responses from respondents suggest that more attention should be paid to the proper labeling of allergenic and intolerant gluten ingredients, as their satisfaction with the labeling ranged on average from 2.74 to 4.31 (

Table 8. Food labeling (indicating whether it contains gluten or is gluten-free).

	Average Grade (1–5)
The declaration on the food about gluten content gives me complete information.	3.09
I can easily orient myself according to the information on the food declaration.	3.29
I can easily decide which food is right for me.	3.41
I trust the information on the packaging of food products.	3.06
I know which ingredients to avoid, so shopping is easy for me.	3.64
The gluten-free information on the product is enough for me, I don’t read the ingredients.	2.74
If I see a crossed-out wheat symbol on the declaration, for me it is a sign that the product does not contain the slightest amount of gluten, I can safely consume the product.	3.55
I am informed about the mandatory labeling of ingredients that cause allergies and intolerance.	3.82
It is easier to learn about allergens and ingredients that cause intolerance since it is mandatory to label.	3.97
Additional labeling of all other foods, which naturally do not contain gluten (e.g., teas, spices, fruit and vegetable products, etc.) with the statement “gluten-free” would be useful and would make the choice easier.	4.31

1—do not agree at all; 2—partially disagree; 3—neither agree nor disagree; 4—agree; 5—completely agree.

). In their opinion, labeling should clearly facilitate the choice to choose the right gluten-free food and it would increase their confidence in purchasing.

Furthermore, most of the respondents believe that additional labeling of all other food, which naturally does not contain gluten (e.g., teas, spices, fruit, and vegetable products, etc.) with the statement “gluten-free” would be useful and facilitate the choice when buying food products. This would facilitate the choice of gluten-free food, but also avoid all the hidden costs associated with excessive use of health care for complications and comorbidities, as well as reduced productivity of people struggling with gluten intolerance [35].

4. Conclusions

The consumption of gluten-free food products has been on the rise in recent years. According to the estimates, this trend will continue in the coming years, so it is important for the food industry to have adequate information about the motivations and needs of consumers for gluten-free products, as well as to understand the critical factors that influence their adherence to a gluten-free diet. The demand for innovation and variety in gluten-free products reflects a shift in consumer preferences towards more diverse options. Consumers are no longer satisfied with the limited choice of simple, familiar gluten-free products. Instead, they want new experiences and flavors that meet their nutritional needs while satisfying their culinary desires. As a result, consumers are looking for gluten-free alternatives with unique ingredients, innovative recipes and flavors.

The gluten-free product market has clearly increased due to the increasing number of people clinically diagnosed with celiac disease. At the same time, there has been a recent increase in the number of consumers who do not suffer from the disease but still follow a gluten-free diet for other reasons.

Today, the range of foods for special dietary needs has expanded considerably. A major advantage of this is that people with food allergies or intolerances can now eat foods that are part of the normal diet but have a special composition (e.g., gluten-free, egg-free). This is important because these special conditions are more likely to have nutrient deficiencies due to dietary restrictions.

Gluten-free diets are characterized by being high in fat and lower in complex carbohydrate sources, dietary fiber, vitamins and minerals.

According to dietary recommendations [36], it is recommended to eat fewer calories, less fat, sugar, salt, and animal protein and more complex carbohydrates, dietary fiber, minerals, and vitamins.

In a lifelong gluten-free diet, the usual wheat flour should be replaced with other ingredients that do not contain harmful proteins but are nutritious and tasty. Fortunately, there are many species of naturally gluten-free plants and pseudocereals (millet, buckwheat, etc.) whose nutritional and technological quality can be improved by the addition of certain substances (e.g., β-glucan, arabinoxylan) [37] or applying special, new technologies [38].

From a nutritional point of view, the crude fiber or dietary fiber content of foods is of paramount importance, as adequate intakes can reduce risk factors for many diseases. Wholegrain cereals are among the most important sources of fiber as they contain the germ, bran, and endosperm parts of the cereal grain as opposed to refined cereals where only the endosperm part is used. Bran and germ contain several nutrients, vitamins, minerals, and phytochemicals, which are lost during refining [39]. Unfortunately, the acceptance of pasta and other products made from wholemeal flours is still not balanced and their consumption is not reaching the desired levels. In addition, by-products from the production of plant foods (e.g., potato peel, apple peel, orange pomace) and special raw materials (chia seeds and quinoa) are excellent sources of fiber [40,41]. In the context of sustainability in food production, data on consumer satisfaction with gluten-free products on the market (availability, quality, taste, and price) can serve the food industry to focus on the development of not only high-quality gluten-free products but also ones that are sustainability sourced and produced. This means the use of environmental friendly ingredients, reducing waste, and optimizing production processes, which lowers the carbon footprint. Additionally, by offering competitively priced sustainable gluten-free products, producers can encourage more consumers to choose eco-friendly products, driving the entire food chain towards greater sustainability.

By turning by-products into a valuable food ingredient, the production of a new generation of nutritionally balanced gluten-free products can represent a healthier choice for consumers while effectively reducing food waste and economically sustainable production.

The production/development of gluten-free products is a challenge for technologists but a necessary one. It is a challenge because of the lack of animal models and the use of ethically unacceptable human tissues, thus reducing the possibility of screening. Currently, the range available on the market is limited, some of them are of low quality (a less than good appearance, taste, aroma, and texture) and expensive. The aim is to ensure a varied and diverse diet and, at the same time, improve product quality by finding the right balance between raw materials and functional additives. These additives should provide valuable nutrients, contribute to the technological properties and result in products that are organoleptically acceptable, i.e., have a good taste, flavor, and shelf life. It is also important to ensure the right technological parameters such as volume and crumb hardness.

Various technologies are currently available to improve dough characteristics, which developers use either individually or in combination [42,43]. These include enzymatic technologies that meet food safety requirements (GRAS—Generally Recognized as Safe), high hydrostatic pressure (HHP) processes, extrusion technologies (such as pre-extruded flours used as gluten substitutes) and sourdough fermentation. In sourdough fermentation, a starter is made from flour, water and yeast containing natural yeasts, lactic acid and acetic acid bacteria and is mainly used for bread production. This process changes the structure of gluten proteins so that they can no longer be recognized by the T-cells of the immune system, making the bread safe for people with gluten sensitivity. Other techniques include drying (or pulverizing) sourdough, the detoxification of gluten proteins or peptides responsible for celiac disease and seed germination, which improves nutritional value by increasing protein digestibility, mineral availability, antioxidant activity and sensory properties.

In the case of gluten-free food, the main objective is still consumer acceptance and correct and clear gluten-free labeling. This is something that needs to be continuously pursued, as our results show.

From all of the above-mentioned points, it can be concluded that additional consumer education is necessary, as well as the development of various, new gluten-free formulations, with the inclusion of new ingredients, to produce a final product with desirable sensory properties, nutritional quality, and an affordable price. This demand offers food manufacturers the opportunity to capitalize on the rapidly growing gluten-free market by developing creative and sustainable products that not only meet dietary requirements, but also take care of environmental sustainability, recycling, packing type, the use of bioingredients, the impact on soil and water, CO₂ impact, and deforestation. Namely, the circular economy, as a very important topic that has emerged in recent years, plays a significant role in reducing resource consumption, eliminating waste, maintaining the continuity of economic development and ensuring recycling, reuse, and re-production and ultimately affects the price and profitability of production of gluten-free products. By focusing on innovation and variety, companies can participate in a profitable market while contributing to the growth of a more sustainable economy.

This study shows that there is a huge opportunity to integrate sustainability into restaurant operations. By developing and promoting gluten-free options that also meet sustainable practices, restaurants can reduce their environmental impact while meeting consumer demands. Further research is needed to identify effective strategies for incorporating sustainable practices into menu development, supply chain management and waste reduction.

The main significance of this study is to highlight consumer dissatisfaction with the current gluten-free product market and to emphasize the potential for innovation and improvement. It identifies key consumer concerns—such as price, availability and variety—and suggests that addressing these issues could open up profitable opportunities for food manufacturers.