Nutritional significance, value‐added applications, and consumer perceptions of food legumes: A review

Legume crops are widely grown worldwide and a primary source of proteins across many least developed countries. These food crops are inherently produced in environmentally sustainable manner and are also an economical source of plant‐based proteins versus animal‐based proteins. The nutrient composition of legumes is very rich, that is, high content of protein, fiber, and bioactive compounds and relatively lower carbohydrates than cereal crops. Although food legumes are a staple in more than 70 countries mostly in Asian, African, and South American regions, the per capita consumption in the Western countries continues to be low in spite of legumes' demonstrated health benefits. However, emerging consumer trends and preferences toward heathy foods, animal protein alternatives, and environmental concerns can enhance the consumption of legume‐based foods. The functional attributes of legume ingredients (e.g., thickening, water‐holding index, gelation, emulsification, and foaming capacity) make legumes suitable for replacing proteins from other sources. The development and marketing of legume‐based ingredients for use in various value‐added food applications have been increasing. The value‐added use of pulse protein isolates and concentrates is expanding fast with substantial use as meat extenders/replacers and meat analogs, milk substitutes, and gluten‐free applications. To increase the utilization of legumes, including legume‐based foods, it is important to focus on research and development efforts that promote “easy‐to‐cook”/prepare foods for consumers, who often avoid legumes due to long cooking times. Addressing this aspect of convenience is particularly critical in developed countries due to the busy lifestyles of consumers and potentially increase legume consumption.


| INTRODUCTION
Legumes crops have both a long and diverse history associated with the development of agricultural practices and meeting human nutritional needs.These food crops have different origins of domestication.Many pulses (i.e., lentils and chickpeas) were generally derived and cultivated in the Middle East regions, whereas common or dry beans (Phaseolus vulgaris L.) are referred to as "new world" crop with small-seeded types (navy, black, pinto) coming from the Mesoamerican region and large-seeded types (kidney, cranberry, yellow Mayacoba) of Andean origins (Miklas et al., 2022).Geographic distribution from these domesticated gene pools has contributed to distinctive global regions of predominant usage.These crops have distinctive sizes, shapes, colors, and flavors that contribute to consumer appeal.Thus, products are prepared and cooked in many regionally specific cuisines (Amin & Borchgrevink, 2022).Legume crops are particularly well suited to cultivation in tropical and humid climates, whereas pulses are more readily adapted to semiarid areas.Sustainable productivity, storage stability, and their nutritional profile distinguish these crops as nutrient and energy-dense foods (Miklas et al., 2022;Uebersax et al., 2022).
Legumes are intrinsically produced in an environmentally sustainable manner, thereby constituting an economical source of proteins as compared with animal sources (Uebersax et al., 2022).Regular consumption of legumes offers a variety of well-documented health benefits (Didinger & Thompson, 2021).These attributes of legumes make them highly suitable for developing value-added products, which can potentially increase the per capita consumption of legumes beyond current levels, especially in the developed countries.The emphasis on increased consumption of food legumes is reflected in government-issued dietary guidelines.The 2015-2020 Dietary Guidelines for Americans (DGA) recommend consuming 1.5 cups ($37.5 g) and 3 cups (75 g) cooked legumes/week for non-vegetarians and vegetarians, respectively (USDHHS & USDA, 2021).
The incorporation of legume-based ingredients in different food products can potentially expand the utilization of legumes beyond traditional uses and consumption patterns.In this regard, there is a heightened potential in the food industry for using legume ingredients in various food systems (Carbonaro et al., 2015;Dhull, Bamal, et al., 2022).Legume-based ingredients are highly suitable for developing diverse food products (Figure 1), including (1) composite mixes and doughs, (2) meat alternatives and extenders, (3) gluten-free products, (4) baked products, (5) snack foods, (6) dairy products, and (7) regional or ethnic products (Hill, 2022).The development, promotion, and consumption of protein-rich legume-based meat alternatives provide consumers with decisive options to the energy intense production and processing of animal-based foods (Ahmad et al., 2022;Hill, 2022).All these "high carbon footprint" operations are known to produce significant waste and pollution that have negative environmental impact.Moreover, the food industry's interest in the development of legume supplementation in otherwise traditional wheat-based foods has increased in the last two decades to cater for healthy food options as well as improved environmental sustainability (Hill, 2022).In order to successfully market new legumebased products, it is essential to improve consumer acceptance through education and communication about benefits of legumes related to health, economics, and the environment.
This article provides an overview of nutritional profile, bioactive compounds, health benefits, value-added ingredients, food applications, culinary/foodservice trends, and consumer perception and acceptance of food legumes.The literature review methodology for this article generally followed the guidelines suggested by Paré and Kitsiou (2017).An extensive search of literature was carried out to collect data and related discussion for about 20 legumes.For proximate composition and mineral content, data were obtained from USDA Food Data Central (USDA, 2022).The primary reason for using USDA's extensive data was to avoid any variations due to potential inconsistencies in analytical methods from different sources.
Nonetheless, data reported by numerous other researchers have been discussed extensively throughout this review article.With respect to consumer acceptance and preferences of food legumes, over 10 studies were reviewed, and key findings are reported in a comprehensive table.

| COMPOSITION AND NUTRITION
Legumes are generally underutilized even though they are excellent and inexpensive sources of protein, dietary fiber (DF), carbohydrates, selected minerals, vitamins, and bioactive phytochemicals (Sreerama et al., 2012).Legumes contain complex carbohydrates, for example, oligosaccharides, DF, and resistant and slowly digestible starch F I G U R E 1 Diverse applications of legume-based ingredients (flour and protein, starch, and fiber fractions).
T A B L E 1 Proximate composition of dry beans and other pulses (per 100 g).(RDS, SDS) in addition to proteins with good amino acid profiles.
Legume proteins are higher in essential amino acids, especially lysine, as compared with animal proteins (Kumar et al., 2022).They have high nutritional values, on average containing 60.76 g carbohydrates, 23.10 g proteins, and 15.55 g DF per 100 g (Table 1).The fat content of legumes is however mostly low, averaging 1.86 g/100 g.Additionally, they contain significant quantities of essential minerals per 100 g, notably potassium (1244 mg), calcium (113 mg), magnesium (177 mg), and phosphorus (367 mg) (Table 2).

| Proteins
The protein content and amino acid profile of legumes are largely determined by the commercial class/cultivar, environment, and use of fertilizers (Singh, 2017).The protein content of pulses (per 100 g) ranges from $19.90 g in adzuki beans to $36.17 g in lupin (Table 1), and it is typically twice the amount of dietary protein levels found in cereals.Globulins constitute the major ($72%) storage proteins, and albumins are the minor (25%) protein fraction.Generally, legumes are considered as incomplete proteins, due to relatively low amounts of some essential sulfur-containing amino acids (cystine and methionine) that are present in larger concentration in cereal grains.According to Curran (2012) and FAO (2014), cereal grains however, have lower content of lysine and tryptophan as compared with legumes.Thus, legumes can be successfully used in complementation with cereals for improved dietary amino acid profile in prepared foods.

| Carbohydrates
Legumes are an excellent source of complex carbohydrates containing 40.37 g/100 g in lupin and up to 63.40 g/100 g in lima beans (Table 1).Thus, legumes do not contribute to the high sugar content of the human diet but rather are important contributors to diets rich in fiber as well as low in glycemic index (GI) (Collins, 2020).Starch, comprising amylose and amylopectin, is the main storage carbohydrate in legume grains (Punia et al., 2020).Moreover, legumes are a valuable source of DF ranging from 5% to 37%, with significant content of soluble and insoluble fiber.Legumes also have high content of resistant starch (RS) and raffinose-family oligosaccharides, all of which are reported to exhibit prebiotic activities (Maphosa & Jideani, 2017).

| Crude fat
The total lipid content of legume seeds varies based on the variety, origin, location, field production conditions, and soil type (Tiwari & Singh, 2012).According to Maphosa and Jideani (2017), legumes are largely low in fat and contain no cholesterol.The fat content per 100 g ranges from 0.38 g in pigeon peas to 9.74 g in lupin (Table 1).
The significantly low-fat content of legumes offers a marketing advantage and make them an attractive, healthy choice for utilization in various food applications.

| Minerals and vitamins
The mineral content of legumes is typically high; however, the bioavailability and digestibility tend to be somewhat poor due to the occurrence of phytate, the primary inhibitor of iron and zinc absorption (Sandberg, 2003).Important minerals present in legumes (per 100 g) include zinc (3.5 mg), iron (6.23 mg), calcium (113 mg), selenium (7.9 mg), phosphorus (367 mg), copper (0.76 mg), potassium (1,244 mg), and magnesium (177 mg) (Table 2).These micronutrients present in legumes altogether play fundamental roles in many cellular metabolic activities and contribute to slowing down natural aging processes through their functions as important cofactors for various antioxidative enzymes (Höhn et al., 2017).Legumes are typically low in sodium (Table 2), a desirable trait considering recent recommendations to reduce sodium in the diet.
Legumes provide considerable amounts of B-complex vitamins (folate, thiamin, and riboflavin); however, they are relatively a poor source of fat-soluble vitamins and vitamin C (Maphosa & Jideani, 2017).

| Bioactive compounds
The bioactive phytochemical found in legumes offer a variety of health benefits.These compounds include oligosaccharides, phenolics, peptides, low molecular weight proteins/peptides, carotenoids, saponins, phytic acid, and antioxidants (Maphosa & Jideani, 2017;Silva et al., 2016;Wiesinger et al., 2022).Previously, these bioactive compounds were considered as antinutritional factors that limited the digestion and absorption of key nutrients.However, current literature (Pedrosa et al., 2021) recognizes these compounds also to be nutritionally active factors with associated health implication such as lowering the risk of coronary heart disease (CHD), type II diabetes, obesity, and body mass index (BMI).Conti et al. (2021) provided comprehensive review of bioactive compounds found in common legumes and their respective properties.Anti-inflammatory, antioxidant, and antimicrobial activities were linked to peptides from albumin and globulin fractions.Phenolic compounds were noted for their role in modulating metabolism, homeostasis, and cell proliferation.The most common polyphenols including phenolic acids, flavonoids, anthocyanins, and tannins are shown in Figure 2.
The phenolic content of legumes varies widely and largely influences the color and pattern of the seedcoat and the type of bean cultivar (Lin et al., 2008).Phenolic acids are contained in the both the cotyledon and seed coat, though the content in the latter is significantly higher.The higher anthocyanin content is typically reported total phenolic concentration of 63.8 mg GAE/g DW in black beans, whereas approximately 0.80 mg GAE/g DW was recorded in green beans (Jiratanan & Liu, 2004).
Flavonoids, consisting of anthocyanins and anthoxanthins, are a major group of polyphenols and are considered as having the highest potential for antioxidant activity.They are common bioactive constituent of legumes notably those with colored testa or seedcoats (Aguilera et al., 2011).Free radical scavenging capacity and antiinflammatory and anticancer properties are some of the notable functional properties exhibited by legume flavonoids.It is important to recognize that these compounds are water soluble and susceptible to leaching losses during aqueous processing; however, they are retained in dry milled ingredients (i.e., whole meals or flours) (Aguilera et al., 2011;Didinger & Thompson, 2021).
Legume proteins, besides having nutritional importance due to their amino acid composition, are also an important source of bioactive peptides.Previous studies have confirmed the biological activities of legume proteins and peptides (Duranti, 2006) (Gautam et al., 2018;Shi et al., 2014).

| Classification of ANFs
According to Soetan and Oyewole (2009), ANFs are natural constituent of plant-based foods that have adverse effects on conventional nutrient intake.The ANFs limit the availability of nutrients resulting in the underutilization of the nutrients (Yacout, 2016).They include glycosides (e.g., saponins), proteins or peptides (e.g., lectins and proteinase inhibitors-trypsin and chymotrypsin), organic acids (e.g., phytic acid), and phenols (e.g., tannins).The commonly found ANFs in selected legumes are shown in Table 3.Generally, these ANFs can be categorized in a variety of ways, including based on their chemical structure, specific action, biosynthetic origin, or physical characteristics.
Tadele ( 2015) presented a two-category classification based on the heat sensitivity of the ANFs.The heat-labile group are mostly proteins with little resistance to temperature changes, whereas the heat-stable group, comprising compounds other than proteins, show relatively high resistance to heat treatments (Peisker, 2013).Huisman and Tolman (2001) classified ANFs into four groups using the stimulated reactions following consumption and resulting impact on nutritive value: • Depressive effect on the digestion and utilization of proteins, for example, tannins, saponins, protease (trypsin and chymotrypsin) inhibitors, and lectins.
• Negative effect on digestive breakdown of carbohydrates, for example, phenols, amylase inhibitors, and flatulence factors.• Negative impact on use and uptake of minerals by the presence of phytates, oxalates, and gossypol.
• Stimulate responses from a hypersensitive immune system.

| Inactivation/reduction of ANFs
The inactivation or reduction of ANFs is critical for the effective utilization of legumes because it enhances the nutritional quality.
There are various simple but effective processing techniques that can be used to reduce the content of ANFs.Examples include cooking, fermentation, germination, dehulling, autoclaving, and soaking (Samtiya et al., 2020).A combination of these processes tends to be more productive at lowering or eliminating the ANF levels.Most ANFs are heat labile; thus, thermal treatment will usually remove or significantly reduce any negative effects from consumption, whereas heat-stable tannins, saponins, and phytic acid are typically reduced by dehulling, soaking, sprouting, and fermentation (Muzquiz et al., 2012).Samtiya et al. (2020) highlighted soaking as a preferred method by which ANFs can be removed from foods due to their solubility in water and subsequent loss through leaching.They also reported that the retention of the seeds in a moist environment facilitates seed germination, which triggers the release of phytase and aids breakdown of phytate.Soaking was observed to have decreased phytate contents in legumes by $33% within 24 h.Increasing the temperature of the soaking water results in an exponential increase in ANF losses.
Depending on the type and duration, thermal treatments have been particularly effective in the reduction of ANFs, which is significant as legumes require heat treatment to render them palatable and safe for consumption.Extended boiling, microwave heating, and autoclaving have all been shown to have significant effect on the ANF content of varied foods.However, autoclaving was the most effective method of lowering (24.7%) phytic acid (Samtiya et al., 2020;Tadele, 2015).Thermal processing lowers pH and facilitates the activation of phytase in legumes.Significant results can be obtained from soaking accompanied by a later application of short heat treatment.

| HEALTH BENEFITS OF LEGUMES
The nutritional relevance of legumes remains undisputed, being an excellent source of macronutrients, namely, proteins, complex carbohydrates, and DF.As key dietary components, legumes are digested much slower as compared with starchy cereals and tubers and thus stimulate satiety.Additionally, this helps to control blood glucose levels by reducing spikes after meal intake (Conti et al., 2021).The DF present in legumes plays a key role in proper gut functioning and is believed to lower the risk of several chronic diseases including some cancers, heart disease, and diabetes.
Legumes possess high RS and carbohydrates with low GI (Munro, 2007).Fiber, oligosaccharides (primarily raffinose, verbascose, stachyose), and RS pass through the stomach and small intestine, remaining undigested due to a lack of enzymes with the capacity to break them down into simpler sugars.In the colon, they can then act as a source of prebiotics for resident probiotics.The bacterial T A B L E 3 Antinutritional constituents commonly found in food legumes.
fermentation results in the formation of short-chain fatty acids, such as butyrate, with potential to improve colon health through promoting a healthier gut microbiome and reducing the risk of colon cancer (Bird et al., 2010).However, production of gases is also associated with the fermentation and can cause bloating, cramping, and flatulence.
Legumes also promote weight reduction due to their satiety value (Li et al., 2014) and help to moderate blood sugar levels after meals, thereby improving insulin sensitivity (Didinger & Thompson, 2021;Mollard et al., 2011).
Legumes can help regulate body weight and obesity.For example, α-amylase inhibitors have been found in legume extracts that slow down the breakdown of starch, which aids in the loss of body weight and fat (Çakir et al., 2019).Polak et al. (2015) reported BMI of below 30 in adult legume consumers, suggesting lowered risk of obesity.
They reviewed data from eight trials and observed a reduction in systolic and arterial blood pressure in more than 50% of the 500 respondents (obese subjects) who ate about a cup of legume daily for a 10-week period.Findings from another study involving 113 obese participants showed significant loss of weight and lowering of blood pressure and waist measurements after consumption of two servings of legumes and four servings of whole grains daily for 18 months, without any refined sugar.
The health-promoting role of legumes in humans is also linked to the different constituent bioactive compounds (Murphy et al., 2018), which have shown to lower the risk of developing noncommunicable diseases, including obesity and type 2 diabetes.These compounds exert a variety of beneficial properties, including modulation of cell proliferation, metabolism, and homeostasis.Furthermore, they possess antioxidant properties that are critical for the prevention of oxidative stress and related diseases (Zhao et al., 2014).
Historically, tannins were considered as antinutrients based on their negative impact on protein digestibility; however, recent research supports the attribution of several health benefits, ranging from antioxidant activity, inhibition of lipid peroxidation, and antimicrobial effect to the intake of tannins (Silva & Pogačnik, 2020).
Legumes also contain significant amounts of peptides and small proteins that exhibit several biological activities, making them suitable as nutraceuticals and/or therapeutic agents (Jeong et al., 2009).
A small cysteine-rich peptide of 70-80 amino acids, termed the Bowman-Birk inhibitor (BBI), is a trypsin-chymotrypsin inhibitor found in soy and other legume species, with potential anticancer activity (Mehdad et al., 2016).
Pulses are noted for their content of phytic acid, which acts as an extensive store of phosphorus in the seeds.Phytic acid occurs mainly as phytate salts of mono-and divalent cations (Zn, Ca, Fe) to which the anionic phosphate groups are tightly bound (Cominelli et al., 2020).Phytic acid thus severely limits the bioavailability of minerals, contributing to hidden hunger, and it is generally considered as an ANF.However, phytates have also been found to possess positive traits.Their mineral chelating ability has been shown to be potentially capable of reducing the occurrence of colorectal carcinoma, lung and mammary cancer, and the formation of kidney stones from salts of oxalates (Gemede & Ratta, 2014).They may also be vital in diabetic diets where they prevent elevated levels of blood glucose by slowing down starch breakdown and controlling insulin production.(Ashogbon et al., 2021;Ratnayake et al., 2001).

| VALUE-ADDED LEGUME INGREDIENTS
In contrast to cereals, starches from legumes are mostly SDS.The SDS is a healthy and the most desirable form of dietary starches due to its slow glycemic response, thus having low GI (Bangar et al., 2022;Chung et al., 2009).Keskin et al. (2022) noted that thorough knowledge of the physical, chemical, and thermal properties of legume fractions, including starch, is important for optimal applications in food formulations.Wani et al. (2016) reported that these properties of legume starch have been analyzed and reported in several studies.
Legumes are rich source of bioactive DF, which has demonstrated benefits for human health (Tosh & Yada, 2010).There are primarily two types of DF, that is, soluble (SDF) and insoluble (IDF).The contents of IDF and SDF differ in seed coat or hulls and the cotyledons, with IDF primarily present in the hulls (cellulose, hemicelluloses, and lignin) and SDF in cotyledons (pectic substances and glucans).The seed coat of legumes contains about 5%-8% on a raw seed weight basis (Hoover & Sosulski, 1985;Keskin et al., 2022).Legume fiber fractions are commercially attractive because they are sufficiently abundant, possess distinctive functional and nutritional properties, and are economical to produce.
Applications of legume fiber products in foods is rapidly expanding with wide use in baked goods, extruded snacks, and formed ingredients and beverages.The application of high-fiber pulse fractions requires careful formulation to assure intended product quality attributes while delivering sufficient water for complete hydration (Tyler et al., 2017).

| FOOD APPLICATIONS OF LEGUME INGREDIENTS
New food product development is mainly driven by the consumers' preferences and latest technological innovations.The functional attributes of legume ingredients (e.g., thickening, water-holding index, gelation capacity, emulsification, and foaming capacity) make legumes suitable for replacing proteins from other sources.Legume-based ingredients can be used for application in a variety of food product segments, which could potentially increase the consumption of legumes beyond traditional uses and low-income consumers.Figure 3 shows a sampling of products prepared from faba beans.Moreover, changing consumer trends, especially, their demand for more plantbased foods that are sustainably produced and preference for "cleanlabel products," have contributed to increased utilization of food legumes through innovative research and development approaches (Amin & Borchgrevink, 2022).Research and development efforts focused on preparing a variety of legume-based products are summarized in Table 4.These products include batters, doughs, breads, dairy applications, extruded snacks, germinated foods, noodles, pasta, miscellaneous baked products, meat extenders, meat analogs, and protein analogs (Hill, 2022;Keskin et al., 2022;Maskus, 2010).
In recent years, one particular segment of legume-based new products has grown significantly, which includes plant-based protein for manufacture of meat analogs.In this regard, legume-derived proteins are evolving as the main source of continually increasing demand for plant proteins worldwide as alternates to meat proteins.
Plant-based meat-like products have been developed possessing sensory quality that is very similar to animal-based meats (Hill, 2022;Keskin et al., 2022).Agri-Food Innovation Council of Canada projected that plant proteins are expected to grow to about one-third of the global protein market by 2024 (AFIC, 2019).The US plantbased meat market, which was $$5 billion in 2018, is likely to grow exponentially to $85 billion by year 2030 (Pritchett, 2019).Presently, Value-added applications of faba/broad beans.Source: Hill (2022).
most of the meat alternatives are produced from soybean and wheat protein, but an increasing number of companies are exploring the use of legume-derived proteins for such products.One prominent example is the use of yellow pea protein because peas allow the product label to market them as free from allergens found in soybean as well as non-GMOs, that is, non-genetically modified organisms (Hill, 2022).
It is noteworthy that some companies are producing meat alternatives by combining two or more plant proteins (including pea), which facilitates improvement of techno-functional and sensory properties of plant-based meats (Amin & Borchgrevink, 2022).It is noted that all plant-substituted meat products must be thoroughly studied and carefully formulated to assure regional regulatory compliance.
Yaffe-Bellany (2019) reported that, to tap into the fast-growing meat alternatives' market, some commercial animal meat processors have initiated marketing of plant-based meat alternatives.It has been reported that, besides development of meat alternatives, legume ingredients continue to be used as meat "extenders" as well as binders in a variety of meat-based products to enhance their nutrient content, texture, and flavor as well as substitute to some allergenic food additives (Hill, 2022).To enhance the flavor, texture/mouthfeel, and overall acceptance of legume-based meat analogs, some GRAS food additives must be incorporated into the meat analog formulations.Extrusion technology, which is the most widely used method for meat analogs manufacture, conveniently allows incorporation of any additives by thoroughly mixing all ingredients.Overall, besides nutritional fortification, appropriate enhancements of palatability, flavor, and shelf life can play a critical role in furthering marketability of legume-based meat alternatives.

| CULINARY AND FOODSERVICE TRENDS
Amin and Borchgrevink ( 2022) noted that without legumes such as beans, the culinary world would be rather a "poorer" place because legumes have a predominant place in most cuisines of the world.At the same time, there is stronger competition from starch-based cuisines, which is suboptimal from a nutritional significance, as legumes provide more balanced food options than the cereal grains.
For example, legumes can be easily incorporated into salads besides main culinary dishes.Nutritionists, public health officials, and food guidelines are increasingly recommending the regular intake of legumes as healthy food choice (HSPH, 2022;Siddiq et al., 2022; USDHHS & USDA, 2021).The FAO declared 2016 as the International Year of the Pulse (IYP), with goals of raising public awareness of the health benefits of legumes/pulses based on their nutrient-dense quality and contribution to more sustainable food production (IYP, 2016).The goals set by FAO align well with consumer preferences, that is, move toward plant-based food options, improved environmental sustainability, "clean-label" ingredients, and distinctive ethnic cuisines.The clean-label food products are generally perceived as "better for you" as they are prepared using all-natural ingredients, that is, without any artificial, synthetic, or GM ingredients.
Among legumes, dry beans have been marketed in canned form traditionally with relatively limited options for other products.
Consumers in developed countries avoid home cooking of beans due to long cooking time involved.By contrast, consumers in Asia, Africa, and South America typically do home cooking of pulses, some of which are relatively easy to cook (shorter cook time), for example, lentils, mung bean, black gram, and split Desi chickpea, to name a few.
Moreover, the use of legumes in different meat and rice cuisines is also common.In addition, an ethnic, dip-type product prepared from chickpeas, Hummus, has become very popular among Western consumers in the last two decades.In recent years, variations of Hummus prepared from some other beans or pulses (lentils, black beans, white beans, and fava/broad beans) are also available in the market (Amin & Borchgrevink, 2022;Siddiq et al., 2022).These added variations and flavors of Hummus have expanded the consumption of this nutrient-rich, health product.
It is particularly noteworthy that dehydrated pasta products are particularly well suited for legume ingredient formulations.The nutritional as well as functional properties of legumes make them an appropriate and readily adapted choice for pasta making, as the partial to full substitution of wheat flour with legume flour produces pasta with higher levels of both protein and fiber.Table 5 shows pasta types that have been produced using legumes and are available in the market.Legumes-based pasta also caters well to consumers who are looking for low-carbohydrate food choices.Advances in processing technologies and optimization of process parameters have enabled pasta manufacturers to offer products that are similar or closer in texture and taste to 100% wheat-based pastas (Amin & Borchgrevink, 2022;Uzunalioglu, 2020).Many foodservice and restaurant establishments are incorporating relatively less expensive ingredients (from beans and pulses) in their cuisines after the recent inflationary price increases of globally traded commodities.Furthermore, an increasing number of restaurants are offering gluten-free choices of dishes for consumers wishing to elect a gluten-free diet and those individuals suffering from celiac disease.This disease has no cure; thus, gluten must be excluded from diet to avoid aggravating symptoms (Amin & Borchgrevink, 2022).
The increase in plant-based options based on legumes is not only associated with retail foodservice.There is a steady increase in plantbased options in K-12 schools, driven by students wanting more plant-based options (Estrada, 2022).Although many individual school districts are offering plant-based meal options, there has been no public funding to encourage districts to provide plant-based options.
In 2022, California passed the Child Nutrition Act (CLI, 2022), establishing the California School Plant-Based Food and Beverage program.
It allows local school districts to be reimbursed up to $0.20 per meal for meals that include plant-based food options, $0.10 for meals that include plant-based milk options, and $0.30 if both plant-based food and milk options are included.Plant-based food option would need to meet the requirements for the USDA meat alternative for the federal National School Lunch Program.This includes beans and legumes, which can be a vegetable or a meat alternative.
During the global pandemic, consumers became more interested in how the environment and the food they eat can impact their health.
There was a greater focus on consuming functional foods, especially those inherently beneficial (Grocery Dive, 2021).Legumes naturally fit into this category.This fits in with an increase in the popularity of ethnic cuisines such as Indian, Middle Eastern, and regional Mexican, all of which rely heavily on legumes (Maras, 2019).With the easing of the pandemic, many consumers are still practicing many of the new habits they developed during quarantine.These include consuming more legume-centric meals both at home and while eating out.

| CONSUMER PERCEPTIONS AND ACCEPTANCE OF LEGUME FOODS
Current consumer perceptions and acceptance of legume foods diverge dramatically from historically near universal acceptance levels to rather segmented appeal based on regional populations, socioeconomic background, and eating patterns.As summarized in Table 6, several studies have been undertaken to characterize demographics and profile of legume consumers, their consumption patterns and rationale for dietary decisions, primarily due to nutritional considerations, cultural tradition, economics, and health benefits.It is clearly recognized that legumes are an underutilized food resource and that most diets will be enhanced nutritionally through an increase in legume intake.Thus, barriers to consumption are frequently studied and various interventions recommended from time to time.
Constraints to legume consumption have been well documented, which often include negative perceptions of the product and are dramatically influenced by many readily available alternatives.Within Western diets, legumes are frequently mentioned as a "poor man's steak" when meat products are widely available and regularly consumed.This long-standing attitude is currently challenged by consumers seeking "healthy and sustainable diets" centered on plantbased proteins.A scientific consensus among health professionals and nutritionists demonstrates the health benefits of a plant-based diet, and legume consumption, particularly for reducing chronic disease risks (Didinger & Thompson, 2021).It is noteworthy that common beans intakes in the United States, which is <7 pounds per capita per annum, dramatically lag behind established dietary recommendations , 2021).This consumption pattern is at variance with their well-recognized positive nutritional profile and health benefits to reduce chronic disease risk.Means to improve general awareness of the health benefits and the specific inclusion in nutrition assistance programs have had limited impact on lower socioeconomic groups.
Further, barriers to increased legume consumption align with a lack of knowledge for preparing and serving legumes.Traditionally, the preparation of beans is not convenient and requires long soaking or cooking times (Siddiq et al., 2022;Uebersax, 2006) T A B L E 6 Summary of consumer perceptions of legumes reported in recent studies.

Study scope Study objective/methodology Main findings Reference
• Access food behaviors, health, and bean nutrition awareness • Determined knowledge and awareness of beans' health benefits, perceptions and consumption frequency, surveyed 71 low-income men (53% White, 16% Black, 31% Hispanic) • White men exhibited significantly higher knowledge about health benefits of beans compared with Black and Hispanic men • Majority of men liked the taste of beans and disagreed that beans took too long to prepare, and 79% ate beans at least 2-3 times/month • By improving men's awareness about beans' health benefits and leveraging existing positive attitudes may further increase bean consumption Heer and Winham (2020) • Assess socio-ecological barriers to dry grain pulse consumption • Determined the socio-ecological influences on beans, peas, lentils, and chickpeas intake among low-socioeconomic women using focus groups and surveys • Women felt that male members of the household preferred meats and that children needed animal-source proteins Consumers generally possess outdated perceptions about flatulence (excessive intestinal gas) and bloating and thus avoid eating beans (Winham & Hutchins, 2011).These researchers conducted a series of clinical feeding trials serving prepared beans (1/2 cup per day for 8 or 12 weeks) and reported that apprehensions about excessive flatulence from consuming beans perhaps might be overstated.It is increasingly evident that when beans are consumed regularly, a metabolic adaptation occurs and gastrointestinal signs and symptoms are diminished over time (Winham et al., 2008) • Assess food intake level and satiety following a serving of pulses in healthy young men with respect to processing, recipe, and legume variety • Determined short-term food intake, subjective appetite, and glycemic response after pulse consumption in by evaluating blood glucose and subjective appetite immediately before consuming the caloric treatment • All caloric treatments showed a decreased subjective appetite • Compared with white bread, none of the pulse treatment lowered food intake at 120 min Wong et al. (2009) consumers about improving consumption patterns and improving the healthy attributes of their diet.Further, this confusion is also prevalent among healthcare professionals (Winham et al., 2018).For example, results from a survey of registered dietitians (RDs) showed that there was a knowledge gap as indicated by a wide range of understanding about the broad-based health attributes of legumes.
Thus, such gap is a barrier to instruction for consumers for increased legume and pulse dietary consumption.The general knowledge indicated that 29% of the registered dieticians did not know the correct meaning of the term "legume" and about 70% could not adequately define the term "pulse."Mitchell et al. (2009) reported that the consumption of dry beans, peas, and lentils could improve the quality of diet Americans.Dietary intake data from the 1999-2002 National Health and Nutrition Examination Survey (NHANES) was used.Results showed that on any given day, <8% of adults are consuming dry beans and peas; Mexican Americans and other Hispanics were more likely to be regular consumers of legumes.Consuming about 1/2 cup dry beans or peas promoted in higher intakes of dietary fiber, protein, folate, Zn, Fe, and Mg, whereas the intake of both saturated and total fat was reduced.
associated with darker colored beans and their presence accounts for the seed coat color in red, black, pink, and mottled classes.The presence of condensed tannins, however, confers light yellow-colored or pink-spotted seed coats.According toLuthria and Pastor-Corrales (2006), the average phenolic acid content of 15 varieties of dry beans was 31.2 mg/100 g, whereas total phenolic acid content ranged between 19.1 and 48.3 mg/100 g.The most common phenolic acids in legumes include caffeic, p-coumaric, sinapic, ferulic, gallic, and p-hydroxybenzoic acids.Ferulic acid was observed to be the most abundant phenolic acid in dry beans.Similar findings were recorded byLopez et al. (2013) in dark beans.Sutivisedsak et al. (2010)

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I G U R E 2 Types of polyphenols present in food legumes (dry beans and pulses).Source: Adapted fromWiesinger et al. (2022).
Ojokoh et al. (2013) investigated the ANF content of fermented cowpea and breadfruit and observed a decrease in phytic acids, oxalate, and hydrogen cyanide contents after fermentation.The fermentation of chickpea also resulted in a 45% reduction in phytates and a 13% increase in protein content.In another study byAdeyemo et al. (2016), different strains of Lactobacillus were used to initiate sorghum fermentation (starter culture) to analyze their effect on the antinutrient composition of the legume over time.These strains used yielded the most effective results in antinutrient reduction after 5 days of fermentation.
Semba et al. (2021) conducted an extensive study to characterize the legume types normally purchased by US consumers and regional and seasonal patterns of legume purchases.Further, this study assessed the adult consumers who have a higher intake of legumes.They utilized retail store checkout scanned data (Nielsen) and the database from 2017-2018 NHANES.Results indicated that the five major legume types purchased in the United States were pinto, black, kidney, and lima beans, and chickpea.The average per capita expenditure was limited (>$5.00annually during 2017-2019 period) and varied widely by geographic region (highest expenditures were in southeastern states and lowest in the selected northern states) and the types of legume products purchased varied widely by regions.Among the NHANES survey 24-h diet recall participants, 20.5% indicated consuming legumes in the preceding 24-h period and were more likely educated Hispanic in larger households.It was observed that age/gender and income level were not significant factors among the participants who did not consume any legumes.The overall conclusion stated that per capita consumption of legumes continues to be low in the United States (which was below the recommended dietary guidelines) and that further research is needed to understand and ameliorate the barriers to US legume consumption.8| CONCLUSIONFood legumes, as nutrient and energy-dense food sources, are produced utilizing diverse agricultural production systems that are both economically and environmentally sustainable.Food legumes have a rich nutritional profile with high protein and fiber content and low fat and sodium contents, and compared with cereal crops, have relatively lower carbohydrate levels.The demonstrated nutrient content and health benefits of food legumes align well with the changing consumer trends for healthy food choices.Moreover, consumers are increasingly opting for a reduction or complete elimination of meat-derived proteins.These positive attributes of legumes make them well suited for developing a variety of valueadded ingredients (flours, protein, starch, fiber) and products, which can potentially increase the per capita consumption of legumes.Soyand pea-based protein concentrates and isolates have traditionally been the most common types of food ingredients produced from legumes.However, demand for protein from other legumes (such as lentils, chickpeas, fava beans, and mung beans) has been consistently increasing.Further, legume starch and fiber fractions also have shown enhanced commercial significance because they possess distinctive functional properties required in diverse food applications.An increasing number of food service and restaurant establishments are incorporating relatively less expensive ingredients (processed from beans and pulses) in their cuisines globally.Furthermore, restaurants are routinely offering gluten-free choices of dishes based on dramatically increased consumer demand.It is well recognized that legumes are an underutilized food resource and that most diets will be significantly enhanced nutritionally through an increase in the daily intake of legumes.The addition of legume-based ingredients in different food products can help in expanding the utilization of legumes beyond traditional uses and consumption patterns.For successful commercialization and sustainable demand, future research must focus on enhancing the quality, improving consumer acceptance, optimizing process/ production challenges, addressing regulatory issues, and ensuring cost effectiveness of legume-based meat analogs.
. Doma et al.Range of commercially available pastas prepared from legumes.