Effect of instant controlled pressure drop on the oligosaccharides, inositol phosphates, trypsin inhibitors and lectins contents of different legumes

Health benefits of legume seeds

Pulses have been part of human nutrition for centuries. They are also used in folk medicine as products with multidirectional medicinal effects. They are annual plants representing the Fabaceae family. Their edible part is the fruit, i.e. the so-called pods. Whole pods or their parts can be eaten, depending on the species and fruit ripeness. Beans, peas, peanuts, chickpeas, lentils, broad beans and soybeans are edible legume species. Legume seeds are characterized by high nutritional value. Compared to seeds from other plants, they have high protein content ranging, on average, from 20% to 35%, depending on the type, growing conditions and maturity of the fruit. This review focuses on various health-promoting properties of legumes and presents their nutritional value and compounds exerting health-promoting effects. Many pulses have a low glycemic index, which is important for prevention and treatment of diabetes. In addition to their low glycemic index and high fiber content, pulses have α-amylase and α-glucosidase inhibitors, which reduce the absorption of glucose from the gastrointestinal tract. These compounds have antidiabetic and anti-inflammatory effects. Pulses have been shown to contain bioactive peptides with angiotensin-converting enzyme inhibitory properties; hence, they are useful in the treatment of cardiovascular diseases. Pulses used in the nutrition of obese individuals provide compounds with pancreatic lipase inhibitory properties, thus promoting weight reduction and control. © 2023 Society of Chemical Industry.

Overview of the Incorporation of Legumes into New Food Options: An Approach on Versatility, Nutritional, Technological, and Sensory Quality

Consumers are more aware and demanding of healthy food options, besides being concerned with environment-friendly consumption. This paper aims to evaluate nutritional, technological, and sensory characteristics of legumes and their products' quality and versatility, considering potential applications in new food options. Legumes are foods that have a recognized nutritional group since they have high protein and fiber content. However, their consumption is still somehow limited for some reasons: in some countries it is not easy to find all the species or cultivars, they need an organization and planning before preparation since they need soaking, and there is the presence of antinutritional factors. Due to the different functionalities of legume proteins, they can be applied to a variety of foods and for different purposes, as grains themselves, aquafaba, extracts, flours, brans, and textured proteins and sprouts. These products have been inserted as ingredients in infant food formulations, gluten-free foods, vegetarian diets, and in hybrid products to reduce food costs as well. Foods such as bread, cakes, cookies, meat analogues, and other baked or cooked products have been elaborated with nutritional, technological and sensory quality. Further development of formulations focused on improving the quality of legume-based products is necessary because of their potential and protein quality.

Naturally Occurring Plant Food Toxicants and the Role of Food Processing Methods in Their Detoxification

Some plant foods evolve defense mechanisms to protect themselves from predators by producing inherent chemicals as secondary metabolites such as cyanogenic glycosides, glycoalkaloids, glucosinolates, pyrrolizidine alkaloids, and lectins. These metabolites are beneficial for the plant itself but toxic to other organisms, including human beings. Some of these toxic chemicals are believed to have therapeutic benefits and are therefore used to protect against chronic health complications such as cancer. Inversely, short- and long-term exposure to significant amounts of these phytotoxins may end up with chronic irreversible negative health problems in important organ systems, and in severe cases, they can be carcinogenic and fatal. A systematic literature search of relevant published articles indexed in Google Scholar®, PubMed®, Scopus®, Springer Link®, Web of Science®, MDPI®, and ScienceDirect databases was used to obtain the necessary information. Various traditional and emerging food-processing techniques have been found to considerably reduce most of the toxicants in the food to their safest level. Despite their ability to preserve the nutritional value of processed foods, emerging food processing methods have limited application and accessibility in middle- and low-income countries. As a consequence, much more work is recommended on the implementation of emerging technologies, with additional scientific work on food processing methods that are effective against these naturally occurring plant food toxicants, particularly pyrrolizidine alkaloids.

Some physicochemical and technological properties of cooking water of pulses as a canned industry waste: effect of ultrasound treatment during soaking

Canned products are important part of human diet and therefore, many types of canned products with high amounts are produced worldwide. During canned production, cooking water of pulses (aquafaba) is an important waste. Therefore, recycling of it is important for sustainability and economic value. In the present study, it was aimed to determine technological properties of aquafabas obtained from canned production. For this aim, chickpea, bean, kidney bean, broad bean, green pea and lentil were used in this study, and conventional soaking and ultrasound soaking was both performed. Aquafaba is a cooking water of pulses not only chickpea and also lentil, pea and bean species. Aquafaba is used for foaming, emulsifying and gelling agent as a plant based food additive. Soaking with ultrasound has shortened the soaking time of all pules as well as increased the D eff (effective diffusion constant) values. Diffusion is a basic physical mechanism for remove moisture or absorb and also give important information about physical and thermal properties of sample. “Remove moisture” term is using for drying and the other is using for hydration. The relationship between the physical properties of pulses and D eff values was observed. The protein content of aquafaba on a dry basis changed between 20 and 35% and it has been observed that there are also positive correlation with their foaming properties. Foaming capacities of aquafabas varied between 167 and 567% in conventional soaking, and between 133 and 533% in ultrasonic soaking. In both methods, chickpea aquafaba showed the lowest foaming capacity and stability, while pea had the highest foaming capacity and stability. US process generally decreased the protein content and foaming capacity (FC) of aquafabas. The foam of pea and lentil aquafabas showed higher resistant against to gravity. In contrary to the foaming properties, an increase in emulsifying properties was observed as a result of US. It has been observed that the obtained aquafabas can be used in various products in the food industry thanks to their technological features instead of animal-based ingredients.

Extrusion Cooking Effect on Carbohydrate Fraction in Novel Gluten-Free Flours Based on Chickpea and Rice

Extrusion cooking allows the development of value-added products from pulses, such as gluten-free snacks with added functional properties. The main objective of this study was to evaluate the changes induced by the extrusion process on the carbohydrate fraction (total carbohydrates, soluble sugars and oligosaccharides, dietary fiber, and arabinoxylans) of novel flour formulations based on chickpeas and rice enriched with different dietary fiber sources. Moreover, the influence of the addition of fiber-rich ingredients, such as Fibersol^® and passion fruit, on the analyzed compounds was also evaluated. Sucrose was the main soluble sugar found in analyzed formulations, and raffinose was the prevalent oligosaccharide, followed by stachyose. The content of total α-galactosides tended to be higher after extrusion cooking. As a consequence of the extrusion treatment, the content of total and soluble dietary fiber was statistically increased in most of the analyzed samples. In general, no significant changes were observed in total arabinoxylan content as a consequence of the extrusion process, while the content of water-soluble arabinoxylans was significantly increased in extruded formulations. It was observed that the content of total available carbohydrates, stachyose, and water-soluble arabinoxylans were significantly influenced by the addition of passion fruit, Fibersol^®, and both. The incorporation of these ingredients in gluten-free formulations based on chickpeas and rice allows one to obtain suitable functional formulations for the development of innovative, gluten-free, extruded snack-type products, which could be an interesting alternative for people with celiac disease.

An Overview on Food Applications of the Instant Controlled Pressure-Drop Technology, an Innovative High Pressure-Short Time Process

Food processing systematically aims at meeting the needs of consumers who are looking for total high quality and perfect food safety. As the various thermal and non-thermal food preservation technologies often affect the natural properties in terms of sensation, flavor, texture, etc., instant controlled pressure drop (DIC) has been conceived as a relevant, innovative process in this field. DIC uses high saturated steam pressure and short duration to provide a new way to expand biological matrices, improve drying, decontaminate, and extract biologically active compounds, among other attributes. Therefore, this review focuses on describing the applications of DIC technology on a wide range of products such as foods and by-products that have been processed both in the laboratory and on an industrial scale. The application of DIC has shown the possibility of a significant leap in quality improvement and cost reduction in the food industry. DIC reduces the drying time of fruits and vegetables, and improves the extraction of essential oils, vegetable oils, and antioxidant components. It also provides strong decontamination, eliminates vegetative microorganisms and spores, and reduces non-nutritional and allergenic components. Over the past 33 years, this technology has continued to expand its food applications and improve its characteristics on an industrial scale. But there are still many food unit operations that can be taken to the next level with DIC.

Aquafaba from Korean Soybean II: Physicochemical Properties and Composition Characterized by NMR Analysis

Aquafaba (AQ) emulsification properties are determined by genetics and seed processing conditions. The physicochemical properties and hydration rates of chickpea (CDC Leader) as a control with proven emulsifying properties were recently reported. Here, we identify correlations between soybean (Backtae, Seoritae, and Jwinunikong) physical, chemical, and hydration properties as well as AQ yield from seed and functional (emulsion and foaming) properties. In addition, a total of 20 compounds were identified by NMR including alcohols (isopropanol, ethanol, methanol), organic acids (lactic acid, acetic acid, succinic acid, citric acid, and malic acid), sugars (glucose, galactose, arabinose, sucrose, raffinose, stachyose), essential nutrients (choline, phosphocholine), amino acids (alanine, glutamine), and polyphenols (resveratrol, glycitin). The process used in this study utilizes a soaking step to hydrate the seed of the selected Korean soybean cultivars. The product, AQ, is an oil emulsifier and foaming agent, which is suitable for use as an egg substitute with improved emulsion/foam formation properties when compared with a chickpea-based AQ.

Effect of inclusion of micronized camelina, sunflower, and flax seeds in the broiler chicken diet on performance productivity, nutrient utilization, and intestinal microbial populations

The aim of the study was to evaluate the effect of inclusion of micronized full-fat camelina, flax, or sunflower seeds in the diet for broiler chickens on the performance productivity, nutrient utilization, and composition of intestinal microbial populations and to assess the possibility of modification of the resistance of isolated bacteria to chemotherapeutic agents with different mechanisms of action. The use of micronized oilseeds improved the broiler chicken body weight (P = 0.035) and the FCR value (P = 0.045) in the final rearing stage by enhancement of the utilization of total protein and organic matter. Lactobacillus-Enterococcus spp., Bifidobacterium spp., Escherichia coli, and Salmonella spp. were isolated from small intestinal contents, and Enterobacteriaceae taxa were detected in the cecum and cloaca of the broiler chickens. The addition of micronized camelina seeds (CAM.IR) contributed to an increase in the Bifidobacterium counts in the small intestine, compared with the control treatment (P < 0.050). Escherichia coli bacteria were not isolated only in the CAM.IR treatment. Nitrofurantoin and chloramphenicol were the most effective agents against the isolates from the cecum and cloaca in all oilseed treatments, whereas streptomycin exhibited the lowest efficacy. In the CAM.IR and micronized sunflower seed (SUN.IR) treatments, there were higher counts of trimethoprim/sulfamethoxazole-resistant Enterobacteriaceae strains than in the control and micronized flax seed (FLA.IR) treatments (P < 0.05). There was a difference between strains isolated from the cecum and cloaca only in the FLA.IR treatment, i.e., increased tetracycline sensitivity was exhibited by strains isolated from the cloaca (13% vs. 50%), also in comparison with the control treatments (P = 0.054). In comparison with the CAM.IR and control treatments, reduced numbers of multi-resistant strains were found in the cloaca isolates from the for FLA.IR and SUN.IR variants. Micronized camelina, flax, and sunflower seeds can be used as part of an effective nutritional strategy focused on optimization of the efficiency of rearing broiler chickens, as they positively modify intestinal microbial populations and increase bacterial sensitivity to the analyzed chemotherapeutic agents.

Extrusion Process as an Alternative to Improve Pulses Products Consumption. A Review

The development of new food products obtained by extrusion processing has increased in recent years. Extrusion is used by the food industry to produce a wide variety of food products, such as ready-to-eat foods (e.g., snacks), among others. Pulses have also gained popularity as novel food ingredients in the formulation of a variety of food and food products, due to their high content of macro and micronutrients, and bioactive compounds that improve the nutritional and functional properties of the final food products. In this review, the impact of extrusion variables on proteins, carbohydrates, vitamins, phenolics and antinutritional compounds in pulses and pulse-based formulations are highlighted. Particularly, the impact of the specific mechanical energy. Also, the preservation, increase and/or reduction in those functional compounds, as a consequence of different extrusion processing conditions, are discussed.

Antinutritional factors, mineral composition and functional properties of dry fractionated flours as influenced by the type of pulse

Coarse (CF) and Fine (FF) fractions were obtained by dry fractionation (air classification) of raw micronized flour (RM) of kabuli chickpea, green pea, yellow and red lentil. Pea showed the highest phytate content in RM and CF. Stachyose was the main oligosaccharide in lentils, exceeding 50 mg g-1, whereas raffinose (39.9 mg g-1) was abundant in chickpea. Antinutritional factors were significantly enriched in FF, whereas decreased in CF. Total-reflection X-ray fluorescence identified potassium as the main macronutrient in pulses. Ca was highly variable, ranging from 0.92 to 0.28 g kg-1 in pea and yellow lentil, respectively. A significant shift of minerals was observed in FF, but despite the highest phytate content, phytate:Zn ratio of lentils was lower than RM, indicating that Zn was enriched more than phytates. Yellow lentil and pea FF showed a protein content higher than 55 g 100g-1. Dry fractionation significantly affected the physicochemical properties, indicating different potential use of fractions.

Nutritional, Antinutritional and Phenolic Properties of Lima Bean (Phaseolus lunatus) Accessions: Underutilized Legume in Ethiopia

The study was aimed to evaluate nutritional compositions, anti- nutritional factors and antioxidant properties of lima bean accessions grown in East Shoa Zone, Ethiopia. The lima bean accessions were studied and compared for their nutritional composition, anti-nutritional factors and antioxidant properties. The result showed that lima bean accessions were good source of vital nutrients when compared to the commonly consumed legumes in Ethiopia. Particularly, lima bean accessions “LB8510” rich in crude protein whereas accession “LB85CH2” rich in crude fiber, total ash and iron and can be implemented for breeding, new product development and used as alternative source of nutrient rich to mitigate malnutrition prevalent in Ethiopia. Therefore, increasing its consumption, cultivation and promotion should be encouraged.

Use of Legumes in Extrusion Cooking: A Review

The traditional perception that legumes would not be suitable for extrusion cooking is now completely outdated. In recent years, an increasing number of studies have been conducted to assess the behavior of various types of legume flours in extrusion cooking, proving that legumes have excellent potential for the production of extruded ready-to-eat foods by partially or totally replacing cereals. This review identifies the optimal processing conditions for legume-based and legume-added extruded foods, which allow the improvement of the expansion ratio and give the extrudates the spongy and crisp structure expected by consumers. In particular, the effect of the individual processing parameters on the physical-chemical and nutritional properties of the final product is highlighted. The extrusion cooking process, indeed, has a positive effect on nutritional characteristics, because it induces important modifications on starch and proteins, enhancing their digestibility, and reduces the content of trypsin inhibitors, lectins, phytic acid, and tannins, typically present in legumes. Therefore, the extrusion of legume flours is a viable strategy to improve their nutritional features while reducing home preparation time, so as to increase the consumption of these sustainable crops.

Inclusion of Limited Amounts of Extruded Legumes Plus Cereal Mixes in Normocaloric or Obesogenic Diets for Rats: Effects on Lipid Profile

Overweight and obesity are regarded as world epidemics and are major risk factors for a number of chronic diseases, including diabetes, cardiovascular diseases, and cancer. Two new highly palatable extruded mixes based on rice and pea (Pisum sativum) or kidney bean (Phaseolus vulgaris) meals were incorporated into normocaloric or obesogenic diets for rats at a low inclusion level (25%). Our purpose was to evaluate the effects of dietary incorporation of this new food ingredient on lipid profile. Organs (heart, liver, kidneys, spleen, stomach, small intestine, colon, cecum) and visceral fat relative weights were different (p < 0.01) from controls for animals fed the obesogenic diets and in rats fed extruded diets with respect to controls. Faecal excretion of bile acids was higher (p < 0.01) for rats fed extruded mixes compared with controls. The inclusion of extruded mixes replacing part of the casein in the control diet lowered liver cholesterol and triglycerides (p < 0.001) and plasma low-density lipoprotein (LDL; p < 0.01) values, although plasma high-density lipoprotein (HDL) was unaltered. Both the inclusion of extruded mixes and the use of obesogenic diets resulted in significantly (p < 0.001) different long chain fatty acid (LCFA) profiles in liver and visceral fat. Incorporating extruded legume plus cereal mixes beneficially influenced lipid metabolism, and would therefore deserve closer attention in human intervention studies, particularly with adolescents. To our knowledge, this is the first report on the nutritional and physiological effects of extruded legume plus cereal mixes.

Cooking Effect on the Bioactive Compounds, Texture, and Color Properties of Cold-Extruded Rice/Bean-Based Pasta Supplemented with Whole Carob Fruit

Pasta is considered as the ideal vehicle for fortification; thus, different formulations of gluten-free pasta have been developed (rice 0-100%, bean 0-100%, and carob fruit 0% or 10%). In this article, the content of individual inositol phosphates, soluble sugars and α-galactosides, protease inhibitors, lectin, phenolic composition, color, and texture were determined in uncooked and cooked pasta. The highest total inositol phosphates and protease inhibitors contents were found in the samples with a higher bean percentage. After cooking, the content of total inositol phosphates ranged from 2.12 to 7.97 mg/g (phytic acid or inositol hexaphosphate (IP6) was the major isoform found); the protease inhibitor activities showed values up to 12.12 trypsin inhibitor (TIU)/mg and 16.62 chymotrypsin inhibitor (CIU)/mg, whereas the competitive enzyme-linked immunosorbent assay (ELISA) showed the elimination of lectins. Considering the different α-galactosides analyzed, their content was reduced up to 70% (p < 0.05) by the cooking process. The total phenols content was reduced around 17-48% after cooking. The cooked samples fortified with 10% carob fruit resulted in darker fettuccine with good firmness and hardness and higher antioxidant activity, sucrose, and total phenols content than the corresponding counterparts without this flour. All of the experimental fettuccine can be considered as functional and healthy pasta mainly due to their bioactive compound content, compared to the commercial rice pasta.

Effect of Instant Controlled Pressure-Drop on the Non-Nutritional Compounds of Seeds and Sprouts of Common Black Bean (Phaseolus vulgaris L.)

The common bean is an important caloric-protein food source. However, its nutritional value may be affected by the presence of non-nutritional compounds, which decrease the assimilation of some nutrients; however, at low concentrations, they show a beneficial effect. Germination and treatment by controlled pressure-drop (DIC, French acronym of Détente Instantanée Contrôlée) are methods that modify the concentration of these components. The objective of this work was to evaluate the change in the non-nutritional composition of bean seeds and sprouts by DIC treatment. The results show that with the germination, the concentration of phenolic and tannin compounds increased 99% and 73%, respectively, as well as the quantity of saponins (65.7%), while phytates and trypsin inhibitors decreased 26% and 42%, respectively. When applying the DIC treatment, the content of phytates (23-29%), saponins (44%) and oligosaccharides increased in bean sprouts and decreased phenolic compounds (4-14%), tannins (23% to 72%), and trypsin inhibitors (95.5%), according to the pressure and time conditions applied. This technology opens the way to new perspectives, especially to more effective use of legumes as a source of vegetable protein or bioactive compounds.

Effect of Instant Controlled Pressure-Drop (DIC), Cooking and Germination on Non-Nutritional Factors of Common Vetch (Vicia sativa spp.)

Legumes are widely consumed by humans, being an important source of nutrients; however, they contain non-nutritional factors (NNFs), such as phytic acid (IP6), raffinose, stachyose, total phenolic compounds, condensed tannins, and flavonoids, that have negative effects on human health. Although vetches (Vicia sativa) are widely cultivated, they are not intended for human feeding due to their contents of NNF. Usually, the NNF are removed by cooking or germinating; however, germination is a process that requires extended time, and cooking may compromise the viability of some nutrients. To promote vetches for human consumption, the effect of the Instant Controlled Pressure Drop (DIC) process was studied as an alternative to cooking and germinating to decrease NNF contents. Results showed that compared to raw vetches, DIC treatment reduced total phenolic compounds (48%), condensed tannins (28%), flavonoids (65%), IP6 (92%), raffinose (77%), and stachyose (92%). These results are very similar to the ones achieved by traditional ways of removing NNF.

Bioactive Compounds, Antioxidant Activity, and Sensory Analysis of Rice-Based Extruded Snacks-Like Fortified with Bean and Carob Fruit Flours

Generally, extruded gluten-free foods are mostly phytochemically deficient. In this study inositol phosphates, α-galactosides, lectins, protease inhibitors, and phenols, their antioxidant activity and sensorial analysis of some rice/bean/whole carob fruit flour blends were determined in unprocessed (controls) and extruded formulations. The fortification of rice-based extrudates with both legumes has a positive influence on both their bioactive compound content and their acceptability by consumers. The extruded formulations contained around twice as much (p < 0.05) total α-galactosides than their unprocessed counterparts. Extrusion significantly reduced the phytic acid content (10%) and significantly increased the less phosphorylated forms (16%-70%). After extrusion, the lectins and protease inhibitors were eliminated. The different phenolic compounds mostly increased (11%-36%), notably in the formulations with carob fruit. The antioxidant activity and the different groups of phenols showed a positive correlation in the extrudates. All the experimental extrudates had higher amounts of bioactive compounds than the commercial extruded rice. Considering the amount of phytochemicals determined in the novel gluten-free extrudates and the scores of sensorial analysis, formulations containing 20%-40% bean and 5% carob fruit could be adequate in promoting health-related functions, helping to increase pulse consumption, and allowing the food industry to satisfy consumers' requirement for functional foods.

Effect of Traditional Household Processes on Iron, Zinc and Copper Bioaccessibility in Black Bean (Phaseolus vulgaris L.)

Micronutrient deficiencies are a major public health problem. Beans are an important plant-based source of iron, zinc and copper, but their absorption is reduced in the presence of anti-nutrients such as phytates, polyphenols and tannins. Soaking and discarding the soaking water before cooking is unanimously recommended, but this can result in mineral loss. Data on the consequences for mineral bioaccessibility is still limited. This study aimed to evaluate iron, zinc and copper bioaccessibility in black beans cooked (regular pan, pressure cooker) with and without the soaking water. For that, three batches of black beans were investigated in triplicate, each split in nine parts (raw grains and four different household processes in duplicate) and analyzed by applying the quarter technique, resulting in a grand total of 164 samples. Minerals were quantified by ICP-MS (inductively coupled plasma mass spectrometry), myo-inositol phosphates (InsP₅, InsP₆) by HPLC (high-performance liquid chromatography) ion-pair chromatography, total polyphenols using Folin-Denis reagent and condensed tannins using Vanillin assay. Mineral bioaccessibility was determined by in vitro digestion and dialysis. All treatments resulted in a statistically significant reduction of total polyphenols (30%) and condensed tannins (20%). Only when discarding the soaking water a loss of iron (6%) and copper (30%) was observed, and InsP₆ was slightly decreased (7%) in one treatment. The bioaccessibility of iron and zinc were low (about 0.2% iron and 35% zinc), but copper presented high bioaccessibility (about 70%). Cooking beans under pressure without discarding the soaking water resulted in the highest bioaccessibility levels among all household procedures. Discarding the soaking water before cooking did not improve the nutritional quality of the beans.

Changes in levels of phytic acid, lectins and oxalates during soaking and cooking of Canadian pulses

Raw and processed (soaked or cooked) seeds of peas, lentils, chickpeas, fava beans and common beans were studied for their contents of antinutritional factors (lectins, phytic acid, total and soluble oxalates), along with soybean as a control. Analysis of variance indicated that legume type, treatment and their interactive effects were significant on these antinutrients. The raw soybean seed was found to contain the highest levels of lectins (692.8 HU/mg), phytic acid (22.91 mg/g), total oxalate (370.5 mg/100 g) and soluble oxalate (200.7 mg/100 g) among all investigated seeds. Relatively high contents of lectins were detected in beans (87.69-88.59 HU/mg) and other pulses ranging from 2.73-11.07 HU/mg. Phytic acid in Canadian pulses varied slightly from 8.55-22.85 mg/g. Total oxalates were variable, ranging from 244.7-294.0 mg/100 g in peas, 168.6-289.1 mg/100 g in lentils, 241.5-291.4 mg/100 g in fava beans, 92.2-214.0 mg/100 g in chickpeas and 98.86-117.0 mg/100 g in common beans. Approximately 24-72% of total oxalate appeared to be soluble in all investigated pulses. Soaking the seeds in distilled water significantly decreased the contents of lectins (0.11-5.18%), total oxalate (17.40-51.89%) and soluble oxalate (26.66-56.29%), but had no impact on phytic acid. The cooking process was found to be more effective in reducing levels of all the investigated antinutritional factors, except phytic acid in common beans and soybean.

Inactivation Methods of Trypsin Inhibitor in Legumes: A Review

Seed legumes have played a major role as a crop worldwide, being cultivated on about 12% to 15% of Earth's arable land; nevertheless, their use is limited by, among other things, the presence of several antinutritional factors (ANFs - naturally occurring metabolites that the plant produces to protect itself from pest attacks.) Trypsin inhibitors (TIs) are one of the most relevant ANFs because they reduce digestion and absorption of dietary proteins. Several methods have been developed in order to inactivate TIs, and of these, thermal treatments are the most commonly used. They cause loss of nutrients, affect functional properties, and require high amounts of energy. Given the above, new processes have emerged to improve the nutritional quality of legumes while trying to solve the problems caused by the use of thermal treatments. This review examines and discusses the methods developed by researchers to inactivate TI present in legumes and their effects over nutritional and functional properties.

The impact of extrusion on the nutritional composition, dietary fiber and in vitro digestibility of gluten-free snacks based on rice, pea and carob flour blends

Consumers and the food industry are demanding healthier products. Expanded snacks with a high nutritional value were developed from different rice, pea and carob flour blends. The proximate composition, starch (total and resistant), amylose and amylopectin, dietary fiber (soluble and insoluble) contents, and the in vitro protein digestibility of different rice-legume formulations, were evaluated before and after the extrusion process. Compared with the corresponding non-extruded blends (control), the extrusion treatment did not change the total protein content, however, it reduced the soluble protein (61-86%), the fat (69-92%) and the resistant starch contents (100%). The total starch content of all studied blends increased (2-19%) after extrusion. The processing increased the in vitro protein digestibility, reaching values around 88-95% after extrusion. Total dietary fiber was reduced around 30%, and the insoluble fraction was affected to a larger extent than the soluble fraction by the extrusion process. Because of its balanced nutritional composition, high dietary fiber content, as well as low energy density, these novel gluten-free snack-like foods could be considered as functional foods and a healthier alternative to commercially available gluten-containing or gluten-free and low nutritional value snacks.

Novel fiber-rich lentil flours as snack-type functional foods: an extrusion cooking effect on bioactive compounds

The effect of extrusion processing on inositol phosphates.

Bioactive proteins and energy value of okara as a byproduct in hydrothermal processing of soy milk

The nutritional properties of raw okara obtained as a byproduct from six soybean varieties during hydrothermal cooking (HTC) of soy milk were assessed. The composition and residual activity (rTIA) of trypsin inhibitors (TIs), contents of lectin, proteins, fats, and carbohydrates, and energy values (EV) were correlated with the respective physicochemical properties of soybean and okara. Kunitz (KTI) and Bowman-Birk (BBI) TIs both comprised okara rTIA. TIs content was higher in okara (5.19-14.40%) than in soybean (3.10-12.17%), which additionally enriched okara by cysteine. Contents of KTI (r = 1.00;p < 0.05) and BBI (r = 0.89;p < 0.05) as well as BBI monomeric (r = 0.89;p < 0.05) and polymeric forms (r = 0.95;p < 0.05) in okara and in soybean were strongly correlated. Low urease index activity indicated that okara was heated adequately to inactivate antinutritional factors. The proximate composition of raw okara, advantageous rTIA, and a very low EV (2.74-3.78 kJ/g) qualify this byproduct for potential application in food preparation as a functional ingredient in dietary products.

Ileal digestibility of amino acids of unheated and autoclaved pea protein concentrate in broilers

The effects of autoclaving 2 varieties of micronized (fine grinding) pea protein concentrate (PPC) on the ileal digestibility (ID) of CP and amino acids (AA) were studied in broilers. There was a control diet based on fermented soybean meal (FSBM) and 4 extra diets in which the FSBM was substituted on a CP basis by PPC from 2 different pea cultivars (PPC-1 and PPC-2), either unheated or autoclaved. Chicks were fed a common diet from 1 to 17 d of age and, then, their respective experimental diets from 18 to 21 d of age. Each treatment was replicated 6 times. Autoclaving reduced trypsin inhibitor activity (TIA) but had little effect on the saponin content of the PPC. The apparent ID (AID) of CP was similar for the FSBM and the unheated PPC and lower for both than for the autoclaved PPC. Autoclaving improved (P < 0.001) the AID of CP (87.6 vs. 82.2%) and most indispensable AA (e.g., 92.1 vs. 88.8% for Lys and 83.6 vs. 76.5% for Thr) of the PPC. The improvement in CP and AA digestibility with autoclaving varied with the PPC used and was consistent with the reduction in TIA observed (9.4 to 2.8 mg/g for PPC-1 vs. 9.1 to 5.3 mg/g for PPC-2). The standardized ID (SID) of most indispensable AA was similar for the FSBM and the PPC-2 and higher for both than for the PPC-1 (P < 0.05). For Lys, the lowest SID value was observed for the FSBM and the highest for the PPC-2 either unheated or autoclaved. It is concluded that the ID of the AA of the PPC improved with heating and was in general higher for the autoclaved PPC than for the FSBM. Consequently, heat processed PPC is a good alternative to FSBM and unheated PPC in starter diets for broilers.