Bioactive Peptides from Germinated Soybean with Anti-Diabetic Potential by Inhibition of Dipeptidyl Peptidase-IV, α-Amylase, and α-Glucosidase Enzymes

Anti-obesity and anti-diabetic bioactive peptides: A comprehensive review of their sources, properties, and techno-functional challenges

The scourge of obesity arising from obesogens and poor dieting still ravages our planet as half of the global population may be overweight and obese by 2035. This metabolic disorder is intertwined with type 2 diabetes (T2D), both of which warrant alternative therapeutic options other than clinically approved drugs like orlistat with their tendency of abuse and side effects. In this review, we comprehensively describe the global obesity problem and its connection to T2D. Obesity, overconsumption of fats, the mechanism of fat digestion, obesogenic gut microbiota, inhibition of fat digestion, and natural anti-obesity compounds are discussed. Similar discussions are made for diabetes with regard to glucose regulation, the diabetic gut microbiota, and insulinotropic compounds. The sources and production of anti-obesity bioactive peptides (AOBPs) and anti-diabetic bioactive peptides (ADBPs) are also described while explaining their structure-function relationships, gastrointestinal behaviors, and action mechanisms. Finally, the techno-functional applications of AOBPs and ADBPs are highlighted.

Enrichment and Quantitation of Dipeptidyl Peptidase IV Inhibitory Peptides in Quinoa upon Systematic Malting

Food-derived peptides with an inhibitory effect on dipeptidyl peptidase IV (DPP-IV) can be used as an additive treatment for type 2 diabetes. The inhibitory potential of food depends on technological protein hydrolysis and gastrointestinal digestion, as the peptides only act after intestinal resorption. The effect of malting as a hydrolytic step on the availability of these peptides in grains has yet to be investigated. In this study, quinoa was malted under systematic temperature, moisture, and time variations. In the resulting malts, the DPP-IV inhibition reached a maximum of 45.02 (±10.28) %, whereas the highest overall concentration of literature-known inhibitory peptides was 4.07 μmol/L, depending on the malting parameters. After in vitro gastrointestinal digest, the inhibition of most malts, as well as the overall concentration of inhibitory peptides, could be increased significantly. Additionally, the digested malts showed higher values in both the inhibition and the peptide concentration than the unmalted quinoa. Concerning the malting parameters, germination time had the highest impact on the inhibition and the peptide concentration after digest. An analysis of the protein sizes before and after malting gave first hints toward the origin of these peptides, or their precursors, in quinoa.

Encapsulation of Tenebrio molitor Hydrolysate with DPP-IV Inhibitory Activity by Electrospraying and Spray-Drying

This study investigates the encapsulation of Tenebrio molitor hydrolysate exhibiting DPP-IV inhibitory activity by spray-drying and electrospraying techniques. First, we optimized the feed formulation and processing conditions required to obtain nano-microcapsules by electrospraying when using Arabic gum as an encapsulating agent and pullulan and Tween 20 as additives. The optimum formulation was also dried by spray-drying, where the removal of the additives was also assayed. Morphology analysis reveals that electrosprayed capsules have a smaller size (1.2 ± 0.5 µm vs. 12.4 ± 8.7 µm) and greater uniformity compared to those obtained by spray-drying. Regarding the surface nitrogen content and DPP-IV inhibitory activity, our results show no significant difference between the electrosprayed capsules and spray-dried capsules containing additives (IC50 of ~1.5 mg protein/mL). Therefore, it was concluded that adding additives during spray-drying allows for a similar encapsulation efficiency and reduced degradation during processing, as achieved by electrospraying technique but providing higher productivity. On the other hand, spray-dried capsules without additives displayed a higher surface nitrogen content percentage, which was mainly due to the absence of Tween 20 in the feed formulation. Consequently, these capsules presented a higher IC50 value (IC50 of 1.99 ± 0.03 mg protein/mL) due to the potential degradation of surface-exposed peptides.

Enhancing the nutritional and bioactive benefits of faba bean flour by combining preprocessing and thermoplastic extrusion: A comprehensive study on digestion-resistant peptides

This research assessed how three preprocessing techniques [soaking (S), soaking and reconstitution (SR), and soaking and dehulling (SD)] impact the protein digestibility and bioactivity of faba bean flours when combined with thermoplastic extrusion. Samples were compared against a control (C) of extruded faba bean flour without preprocessing. Applying preprocessing techniques followed by extrusion diminished antinutrient levels while enhancing protein hydrolysis and in vitro bioactivity in higher extent compared to C. Specifically, SD combined with extrusion was the most effective, achieving an 80% rate of protein hydrolysis and uniquely promoting the release of gastric digestion-resistant proteins (50-70 kDa). It also resulted in the highest release of small peptides (<3kDa, 22.51%) and free amino acids (15.50%) during intestinal digestion. Moreover, while all preprocessing techniques increased antioxidant (ABTS radical-scavenging), antidiabetic, and anti-hypertensive activities, SD extruded flour displayed the highest levels of dipeptidyl peptidase inhibition (DPP-IVi, IC50=13.20 µg/mL), pancreatic α-amylase inhibition (IC50=8.59 mg/mL), and angiotensin I-converting enzyme inhibition (ACEi, IC50=1.71 mg protein/mL). As a result, it was selected for further peptide and in silico bioactive analysis. A total of 24 bioactive peptides were identified in intestinal digests from SD extruded flour, all with potential DPP-IVi and ACEi activities, and six were also predicted as antioxidant peptides. VIPAGYPVAIK and GLTETWNPNHPEL were highlighted as resistant bioactive peptides with the highest antidiabetic and antioxidant potential. Our findings demonstrated that combining preprocessing (particularly SD) and thermoplastic extrusion enhances protein digestibility in faba beans and promotes the release of beneficial bioactive peptides in the intestine.

Formation of dipeptidyl peptidase-IV (DPP-IV) inhibitory peptides from Jack Bean (Canavalia ensiformis (L.) DC.) sprout in simulated digestion

Bean sprouts are potential plant proteins that produce DPP-IV inhibitory peptides. These peptides must be stable and active in the brush border membrane of the small intestine to inhibit DPP-IV. The purpose of this research is to evaluate the DPP-IV inhibitory activity of jack bean sprouts using pepsin-pancreatin during simulated digestion, as well as the absorption of these peptides through the everted gut sac method. The results showed that after 180 min of digestion simulation, the Mw < 1 kDa peptide fraction of jack bean hydrolysate, which germinated for 60 h (HG60), had the highest inhibitory activity. The duodenum absorbs most of the peptides with inhibitory activity of 61.77%, which is slightly lower than activity after digestion (62.19%). These outcomes suggest that the DPP-IV inhibitory activity of HG60 can be maintained after digestion and absorption. Two novel peptides KAVGDPI and QGVVLRP identified after absorption contain crucial amino acids confirming as DPP-IV inhibitor.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01343-9.

An in-vitro evaluation of antifungal, anti-lungcancer (A549), and anti-hyperglycemic activities potential of Andrographis paniculata (Burm. f.) flower extract

The medical plant research has received more attention among researchers especially after the Covid-19 pandemic. This research performed to evaluate the antifungal, anti-lung cancer (A549), and anti-hyperglycemic activities of aqueous extract of Andrographis paniculata flower. Interestingly, A. paniculata flower aqueous extract contains pharmaceutically valuable phytochemicals such as alkaloid, phenolics, terpenoids, tannins, flavonoids, and protein. It also showed fine antifungal activity against test fungal pathogens in the following order as: Aspergillus niger > Fusarium solani > Trichoderma harzianum > A. parasiticus > P. expansum > Penicillium janthinellum with lowest MIC values as ranged from 100 to 300 μg mL-1. Interestingly, this aqueous extract also showed considerable anti-lung cancer activity, evidenced by dose and time dependent lung cancer cell line (A549) growth/proliferation inhibition/cytotoxicity activity (65%) at 300 μg mL-1 concentration. This can be achieved by plant extract through inducing the secretion of apoptosis related proteins such as TNF α, IFN-γ, and ınterleukin 2 leads to apoptosis in A549 cells. It also showed fine anti-diabetic activity by inhibiting α -amylase (58.41%) than α-glucosidase (54.74%) at 200 μg mL-1 concentration. The UV as well as FTIR results demonstrated that the aqueous extract of A. paniculata flower contains pharmaceutically valuable bioactive compounds, which may be responsible for the wide range of biomedical applications.

The inhibitory mechanism of amylase inhibitors and research progress in nanoparticle-based inhibitors

Type 2 diabetes is caused by persistently high blood sugar levels, which leads to metabolic dysregulation and an increase in the risk of chronic diseases such as diabetes and obesity. High levels of rapidly digestible starches within foods may contribute to high blood sugar levels. Amylase inhibitors can reduce amylase activity, thereby inhibiting starch hydrolysis, and reducing blood sugar levels. Currently, amylase inhibitors are usually chemically synthesized substances, which can have undesirable side effects on the human body. The development of amylase inhibitors from food-grade ingredients that can be incorporated into the human diet is therefore of great interest. Several classes of phytochemicals, including polyphenols and flavonoids, have been shown to inhibit amylase, including certain types of food-grade nanoparticles. In this review, we summarize the main functions and characteristics of amylases within the human body, as well as their interactions with amylase inhibitors. A strong focus is given to the utilization of nanoparticles as amylase inhibitors. The information covered in this article may be useful for the design of functional foods that can better control blood glucose levels, which may help reduce the risk of diabetes and other diet-related diseases.

A Quinoa Protein Hydrolysate Fractionated by Electrodialysis with Ultrafiltration Membranes Improves Maternal and Fetal Outcomes in a Mouse Model of Gestational Diabetes Mellitus

SCOPE

Quinoa intake exerts hypoglycemic and hypolipidemic effects in animals and humans. Although peptides from quinoa inhibit key enzymes involved in glucose homeostasis in vitro, their in vivo antidiabetic properties have not been investigated.

METHODS AND RESULTS

This study evaluated the effect of oral administration of a quinoa protein hydrolysate (QH) produced through enzymatic hydrolysis and fractionation by electrodialysis with ultrafiltration membrane (EDUF) (FQH) on the metabolic and pregnancy outcomes of Lepdb/+ pregnant mice, a preclinical model of gestational diabetes mellitus. The 4-week pregestational consumption of 2.5 mg mL-1 of QH in water prevented glucose intolerance and improves hepatic insulin signaling in dams, also reducing fetal weights. Sequencing and bioinformatic analyses of the defatted FQH (FQHD) identified 11 peptides 6-10 amino acids long that aligned with the quinoa proteome and exhibited putative anti-dipeptidyl peptidase-4 (DPP-IV) activity, confirmed in vitro in QH, FQH, and FDQH fractions. Peptides homologous to mouse and human proteins enriched for biological processes related to glucose metabolism are also identified.

CONCLUSION

Processing of quinoa protein may be used to develop a safe and effective nutritional intervention to control glucose intolerance during pregnancy. Further studies are required to confirm if this nutritional intervention is applicable to pregnant women.

Screening and Activity Analysis of α-Glucosidase Inhibitory Peptides Derived from Coix Seed Prolamins Using Bioinformatics and Molecular Docking

Hydrolysates of coix seed prolamins (CHPs) have an excellent hypoglycemic effect and can effectively inhibit α-glucosidase, which is the therapeutic target enzyme for type 2 diabetes mellitus. However, its hypoglycemic components and molecular mechanisms remain unclear, and its stability in food processing needs to be explored. In this study, four potential α-glucosidase inhibitory peptides (LFPSNPLA, FPCNPLV, HLPFNPQ, LLPFYPN) were identified and screened from CHPs using LC-MS/MS and virtual screening techniques. The results of molecular docking showed that the four peptides mainly inhibited α-glucosidase activity through hydrogen bonding and hydrophobic interactions, with Pro and Leu in the peptides playing important roles. In addition, CHPs can maintain good activity under high temperatures (40~100 °C) and weakly acidic or weakly alkaline conditions (pH 6.0~8.0). The addition of glucose (at 100 °C) and NaCl increased the inhibitory activity of α-glucosidase in CHPs. The addition of metal ions significantly decreased the inhibitory activity of α-glucosidase by CHPs, and their effects varied in magnitude with Cu2+ having the largest effect followed by Zn2+, Fe3+, K+, Mg2+, and Ca2+. These results further highlight the potential of CHPs as a foodborne hypoglycemic ingredient, providing a theoretical basis for the application of CHPs in the healthy food industry.

Impact of thermal treatments and simulated gastrointestinal digestion on the α-amylase inhibitory activity of different legumes

Legumes are excellent sources of proteins that can be hydrolysed to generate antidiabetic peptides, which inhibit carbohydrate digestive enzymes. The degree of protein hydrolysis depends on the thermal treatment applied and how it impacts protein denaturation and thus accessibility to enzymes. In this study, α-amylase inhibitory activities of cooked (conventional, pressure, and microwave cooking) and digested (simulated gastrointestinal digestion, GID) green pea, chickpea, and navy beans were evaluated, together with the impact of thermal treatments on peptide profiles after GID. All peptides extracts inhibited α-amylase after cooking and GID, and the peptide fraction <3 kDa was responsible for main activity. In green peas and navy beans, microwave cooking showed the highest impact whereas none thermal treatment highlighted in chickpeas. The peptidomics analysis of the fractions <3 kDa identified a total of 205 peptides, 43 of which were found to be potentially bioactive according to in silico analysis. Also quantitative results evidenced differences in the peptide profile between the type of legume and thermal treatment.

Exploring the Multifaceted Potential of a Peptide Fraction Derived from Saccharomyces cerevisiae Metabolism: Antimicrobial, Antioxidant, Antidiabetic, and Anti-Inflammatory Properties

The rising demand for minimally processed, natural, and healthier food products has led to the search for alternative and multifunctional bioactive food components. Therefore, the present study focuses on the functional proprieties of a peptide fraction derived from Saccharomyces cerevisiae metabolism. The antimicrobial activity of the peptide fraction is evaluated against various foodborne pathogens, including Candida albicans, Candida krusei, Escherichia coli, Listeria monocytogenes, and Salmonella sp. The peptide fraction antioxidant properties are assessed using FRAP and DPPH scavenging capacity assays. Furthermore, the peptide fraction's cytotoxicity is evaluated in colorectal carcinoma and normal colon epithelial cells while its potential as an antidiabetic agent is investigated through α-amylase and α-glucosidase inhibitory assays. The results demonstrate that the 2-10 kDa peptide fraction exhibits antimicrobial effects against all tested microorganisms, except C. krusei. The minimal inhibitory concentration for E. coli, L. monocytogenes, and Salmonella sp. remains consistently low, at 0.25 mg/mL, while C. albicans requires a higher concentration of 1.0 mg/mL. Furthermore, the peptide fraction displays antioxidant activity, as evidenced by DPPH radical scavenging activity of 81.03%, and FRAP values of 1042.50 ± 32.5 µM TE/mL at 1.0 mg/mL. The peptide fraction exhibits no cytotoxicity in both tumor and non-tumoral human cells at a concentration up to 0.3 mg/mL. Moreover, the peptide fraction presents anti-inflammatory activity, significantly reducing the expression of the TNFα gene by more than 29.7% in non-stimulated colon cells and by 50% in lipopolysaccharide-stimulated colon cells. It also inhibits the activity of the carbohydrate digestive enzymes α-amylase (IC50 of 199.3 ± 0.9 µg/mL) and α-glucosidase (IC20 of 270.6 ± 6.0 µg/mL). Overall, the findings showed that the peptide fraction exhibits antibacterial, antioxidant, anti-inflammatory, and antidiabetic activity. This study represents a step forward in the evaluation of the functional biological properties of S. cerevisiae bioactive peptides.

Inhibitory Potential of Synthetic Amino Acid Derivatives against Digestive Enzymes as Promising Hypoglycemic and Anti-Obesity Agents

Over the last decades, the increased incidence of metabolic disorders, such as type two diabetes and obesity, has motivated researchers to investigate new enzyme inhibitors. In this study, the inhibitory effects of synthetic amino acid derivatives (PPC80, PPC82, PPC84, PPC89, and PPC101) on the activity of digestive enzymes were assessed using in vitro assays. The inhibitory effect was determined by the inhibition percentage and the 50% inhibitory concentration (IC₅₀), and the mechanism of action was investigated using kinetic parameters and Lineweaver-Burk plots. PPC80, PPC82, and PPC84 inhibited pancreatic lipase (IC₅₀ of 167-1023 µM) via competitive or mixed mechanisms. The activity of pancreatic α-amylase was suppressed by PPC80, PPC82, PPC84, PPC89, and PPC101 (IC₅₀ of 162-519 µM), which acted as competitive or mixed inhibitors. Finally, PPC84, PPC89, and PPC101 also showed potent inhibitory effects on α-glucosidase (IC₅₀ of 51-353 µM) as competitive inhibitors. The results suggest that these synthetic amino acid derivatives have inhibitory potential against digestive enzymes and may be used as therapeutic agents to control metabolic disorders.

β-Conglutins' Unique Mobile Arm Is a Key Structural Domain Involved in Molecular Nutraceutical Properties of Narrow-Leafed Lupin (Lupinus angustifolius L.)

Narrow-leafed lupin (NLL; Lupinus angustifolius L.) has multiple nutraceutical properties that may result from unique structural features of β-conglutin proteins, such as the mobile arm at the N-terminal, a structural domain rich in α-helices. A similar domain has not been found in other vicilin proteins of legume species. We used affinity chromatography to purify recombinant complete and truncated (without the mobile arm domain, tβ5 and tβ7) forms of NLL β5 and β7 conglutin proteins. We then used biochemical and molecular biology techniques in ex vivo and in vitro systems to evaluate their anti-inflammatory activity and antioxidant capacity. The complete β5 and β7 conglutin proteins decreased pro-inflammatory mediator levels (e.g., nitric oxide), mRNA expression levels (iNOS, TNFα, IL-1β), and the protein levels of pro-inflammatory cytokine TNF-α, interleukins (IL-1β, IL-2, IL-6, IL-8, IL-12, IL-17, IL-27), and other mediators (INFγ, MOP, S-TNF-R1/-R2, and TWEAK), and exerted a regulatory oxidative balance effect in cells as demonstrated in glutathione, catalase, and superoxide dismutase assays. The truncated tβ5 and tβ7 conglutin proteins did not have these molecular effects. These results suggest that β5 and β7 conglutins have potential as functional food components due to their anti-inflammatory and oxidative cell state regulatory properties, and that the mobile arm of NLL β-conglutin proteins is a key domain in the development of nutraceutical properties, making NLL β5 and β7 excellent innovative candidates as functional foods.

Production of Food-Derived Bioactive Peptides with Potential Application in the Management of Diabetes and Obesity: A Review

The prevalence of diabetes mellitus and obesity is increasing worldwide. Bioactive peptides are naturally present in foods or in food-derived proteins. Recent research has shown that these bioactive peptides have an array of possible health benefits in the management of diabetes and obesity. First, this review will summarize the top-down and bottom-up production methods of the bioactive peptides from different protein sources. Second, the digestibility, bioavailability, and metabolic fate of the bioactive peptides are discussed. Last, the present review will discuss and explore the mechanisms by which these bioactive peptides help against obesity and diabetes based on in vitro and in vivo studies. Although several clinical studies have demonstrated that bioactive peptides are beneficial in alleviating diabetes and obesity, more double-blind randomized controlled trials are needed in the future. This review has provided novel insights into the potential of food-derived bioactive peptides as functional foods or nutraceuticals to manage obesity and diabetes.

The Beneficial Effects of Soybean Proteins and Peptides on Chronic Diseases

With lifestyle changes, chronic diseases have become a public health problem worldwide, causing a huge burden on the global economy. Risk factors associated with chronic diseases mainly include abdominal obesity, insulin resistance, hypertension, dyslipidemia, elevated triglycerides, cancer, and other characteristics. Plant-sourced proteins have received more and more attention in the treatment and prevention of chronic diseases in recent years. Soybean is a low-cost, high-quality protein resource that contains 40% protein. Soybean peptides have been widely studied in the regulation of chronic diseases. In this review, the structure, function, absorption, and metabolism of soybean peptides are introduced briefly. The regulatory effects of soybean peptides on a few main chronic diseases were also reviewed, including obesity, diabetes mellitus, cardiovascular diseases (CVD), and cancer. We also addressed the shortcomings of functional research on soybean proteins and peptides in chronic diseases and the possible directions in the future.

Legume-Derived Bioactive Peptides in Type 2 Diabetes: Opportunities and Challenges

Diabetes mellitus is a complex disorder characterized by insufficient insulin production or insulin resistance, which results in a lifelong dependence on glucose-lowering drugs for almost all patients. During the fight with diabetes, researchers are always thinking about what characteristics the ideal hypoglycemic drugs should have. From the point of view of the drugs, they should maintain effective control of blood sugar, have a very low risk of hypoglycemia, not increase or decrease body weight, improve β-cell function, and delay disease progression. Recently, the advent of oral peptide drugs, such as semaglutide, brings exciting hope to patients with chronic diabetes. Legumes, as an excellent source of protein, peptides, and phytochemicals, have played significant roles in human health throughout human history. Some legume-derived peptides with encouraging anti-diabetic potential have been gradually reported over the last two decades. Their hypoglycemic mechanisms have also been clarified at some classic diabetes treatment targets, such as the insulin receptor signaling pathway or other related pathways involved in the progress of diabetes, and key enzymes including α-amylase, α-glucosidase, and dipeptidyl peptidase-IV (DPP-4). This review summarizes the anti-diabetic activities and mechanisms of peptides from legumes and discusses the prospects of these peptide-based drugs in type 2 diabetes (T2D) management.

In Vitro Assessment Methods for Antidiabetic Peptides from Legumes: A Review

Almost 65% of the human protein supply in the world originates from plants, with legumes being one of the highest contributors, comprising between 20 and 40% of the protein supply. Bioactive peptides from various food sources including legumes have been reported to show efficacy in modulating starch digestion and glucose absorption. This paper will provide a comprehensive review on recent in vitro studies that have been performed on leguminous antidiabetic peptides, focusing on the α-amylase inhibitor, α-glucosidase inhibitor, and dipeptidyl peptidase-IV (DPP-IV) inhibitor. Variations in legume cultivars and methods affect the release of peptides. Different methods have been used, such as in sample preparation, including fermentation (t, T), germination (t), and pre-cooking; in protein extraction, alkaline extraction, isoelectric precipitation, phosphate buffer extraction, and water extraction; in protein hydrolysis enzyme types and combination, enzyme substrate ratio, pH, and time; and in enzyme inhibitory assays, positive control type and concentration, inhibitor or peptide concentration, and the unit of inhibitory activity. The categorization of the relative scale of inhibitory activities among legume samples becomes difficult because of these method differences. Peptide sequences in samples were identified by means of HPLC/MS. Software and online tools were used in bioactivity prediction and computational modelling. The identification of the types and locations of chemical interactions between the inhibitor peptides and enzymes and the type of enzyme inhibition were achieved through computational modelling and enzyme kinetic studies.

Multifunctional bioactive properties of hydrolysates from colocynth (Citrullus colocynthis) seeds derived proteins: Characterization and biological properties

Citrullus colocynthis (Colocynth) has gained a great deal of interest in their applications as indigenous nutraceutical and as a functional food ingredient. The intact colocynth seed protein was enzymatically hydrolyzed using proteolytic enzymes (alcalase, bromelain, and chymotrypsin) at different time intervals of 3, 6, and 9 h. The highest degree of hydrolysis (87.82%) was observed in chymotrypsin derived colocynth seed protein hydrolysates (CSPH) for 9 h. The CSPHs was further investigated through in-vitro assay to explore its potential biological activity such as antioxidant, inhibition of enzymatic marker related to diabetes (DPP-IV, α-glucosidase and α-amylase) and hyperlipidaemia (cholesteryl esterase and pancreatic lipase). Chymotrypsin hydrolysate showed the strongest DPPH (65.7 mM TEAC) and ABTS (525.2 mM TEAC) radical scavenging activity after 6 h of hydrolysis. Moreover, chymotrypsin-treated CSPH for 6 h inhibited cholesteryl esterase (IC₅₀ = 13.68 μg/mL) and pancreatic lipase (IC₅₀ = 14.12 μg/mL) significantly when compared to native protein. Whereas, bromelain and alcalase treated hydrolysate for 6 h effectively inhibited α-glucosidase and α-amylase at an inhibitory concentration of IC₅₀ = 13.27 μg/mL and of IC₅₀ = 17 μg/mL. Overall, the findings indicated that protein hydrolysates exhibited superior biological activity than intact colocynth seed proteins isolate (CSPI) and could be a sustainable source of bioactive peptides.

Potential Role of Bioactive Proteins and Peptides Derived from Legumes towards Metabolic Syndrome

Legumes have been widely consumed and used to isolate bioactive compounds, mainly proteins. The aim of this study was to review the beneficial actions of different legumes proteins and peptides updating the main findings that correlate legumes consumption and the effects on non-transmissible chronic diseases, specifically metabolic syndrome. An exhaustive revision of five relevant bioactivities (antioxidant, anti-inflammatory, antihypertensive, hypocholesterolemic -all of them linked to metabolic syndrome- and antitumoral) of proteins and peptides from legumes focused on isolation and purification, enzymatic hydrolysis and in vitro gastrointestinal digestion was carried out. The promising potential of bioactive hydrolysates and peptides from pulses has been demonstrated by in vitro tests. However, only a few studies validated these biological activities using animal models. No clinical trials have been carried out yet; so further research is required to elucidate their effective health implications.

Pigeon pea penta- and hexapeptides with antioxidant properties also inhibit renin and angiotensin-I-converting enzyme activities

Pigeon pea protein was sequentially digested with pepsin followed by pancreatin and the hydrolysate separated into 18 fractions using reversed-phase high-performance liquid chromatography. Fractions were analyzed for in vitro antioxidant properties (radical scavenging, metal chelation, and ferric iron reducing ability) in addition to inhibition of renin and angiotensin-converting enzyme (ACE). The most active fractions were analyzed by mass spectroscopy followed by identification of 10 peptide sequences (7 pentapeptides and 3 hexapeptides). All the peptides showed a wide range of multifunctional activity by scavenging hydroxyl (31.9-66.8%) and superoxide (25.6-100.0%) radicals in addition to ACE inhibition (7.4-100%) with significant (p < .05) differences between the peptides. AGVTVS, TKDIG, TSRLG, GRIST, and SGEKI were the most active; however, AGVTVS had the highest hydrophobic residue and exhibited the strongest activity against ACE, renin as well as superoxide and hydroxyl radicals. PRACTICAL APPLICATIONS: There is an increasing attraction of researchers to food peptides especially from legume proteins. Enzymatic digestion as well as high performance liquid chromatography (HPLC) purification has become an important process used to separate peptides with significant biological activities and health-promoting effects. There is useful information regarding the bioactive and functional (in vitro antioxidant, antidiabetic, in vitro/in vivo antihypertensive) properties of hydrolyzed and ultra-filtered pigeon pea fractions but scant research output still exists for purified peptides from pigeon pea establishing their therapeutic potential. The present study aimed to separate peptide fractions from pigeon pea hydrolysate and identify available amino acid sequences from the parent protein. Therefore, peptide sequences generated from the most bioactive fractions showed prospects for the expanded industrial utilization of pigeon pea. Further promoting its application as functional ingredient or additive for alleviating angiotensin-converting enzyme-related diseases.

An investigation of correlation between structural and functional properties of Nigella sativa protein isolate

The physicochemical characteristics, amino acid composition, and functional properties of Nigella sativa (NS) seedcake protein extracts were evaluated to establish their potential in nutraceuticals and functional foods. The highest yield (20.2%) of protein isolate (NSPI) from NS seedcake was achieved at an alkali concentration of 0.16 M, a buffer to sample ratio of 1/25 (w/v), extraction time, 15 min, and extraction temperature, 25°C. Amino acid analysis showed that the isolated protein is a good source of amino acids with a significant essential to total amino acid (E/TN) ratio. Further, the protein isolate exhibited maximum solubility at pH 11. The results of the physicochemical analysis clearly indicated that the protein isolate had good water and oil holding capacity, emulsification property, foaming capacity, and foaming stability. The secondary structure of NSPI contained α-helix, β-sheet, and β-turns. In addition, NSPI showed excellent antioxidant, anti-diabetic, and protein digestibility activities. From the experimental data, it could be concluded that NSPI could be an excellent source of proteins for the development of foods with promising functional properties. PRACTICAL APPLICATIONS: Nigella sativa seeds are frequently used as a natural food additive and have been a part of naturopathy for centuries due to their anti-inflammatory, antibacterial, anticancer, antidiabetic, immunomodulatory, and cardioprotective properties. Nigella sativa seedcakes obtained as by-products of the oil extraction process are rich in protein content and can be used as a sustainable source of dietary proteins to cater to a wide range of consumers. Being plant-based, they inherently possess several medicinal properties. Analyzing the physicochemical and functional properties of protein isolated from seedcakes allows us to optimize the protein extraction process while providing a better perspective on its potential in the nutraceuticals and food industries. It can be used as an energy supplement in animal feed as a source of protein to replace soybeans and barley. The antioxidant proteins when added to meat-based products have been known to protect the meat from oxidative stress as well as pathogenic organisms, thus, improving its shelf-life. Nigella sativa protein isolates have several applications in the pharmaceutical industry as well.

Multi-Bioactivity of Protein Digests and Peptides from Oat (Avena sativa L.) Kernels in the Prevention of the Cardiometabolic Syndrome

The aim of this study was to characterize the digests and peptides derived from oat kernel proteins in terms of their major enzyme inhibitory activities related to the prevention of cardiometabolic syndrome. It also entailed the characteristics of antioxidant bioactivity of the analyzed material. The study was carried out using coupled in silico and in vitro methods. The additional goal was to investigate whether identified peptides can pervade Caco-2 cells. Based on the results of bioinformatic analysis, it was found that the selected oat proteins may be a potential source of 107 peptides with DPP-IV and/or ACE inhibitory and/or antioxidant activity. The duodenal digest of oat kernels revealed multiple activities. It inhibited the activities of the following enzymes: DPP-IV (IC₅₀ = 0.51 vs. 10.82 mg/mL of the intact protein), α-glucosidase (IC₅₀ = 1.55 vs. 25.20 mg/mL), and ACE (IC₅₀ = 0.82 vs. 34.52 mg/mL). The DPPH^• scavenging activity was 35.7% vs. 7.93% that of the intact protein. After in silico digestion of oat proteins, 24 peptides were selected for identification using LC-Q-TOF-MS/MS. Among them, 13 sequences were successfully identified. One of them, i.e., VW peptide, exhibited triple activities, i.e., DPP-IV and ACE inhibitory and DPPH^• scavenging activity. The multifunctional peptides: PW, TF, VF, and VW, were identified in the basolateral samples after transport experiments. Both in silico and in vitro analyses demonstrated that oat kernel proteins were the abundant sources of bioactive digests and peptides to be used in a diet for patients suffering from cardiometabolic syndrome.

Critical Review for the Production of Antidiabetic Peptides by a Bibliometric Approach

The current bibliometric review evaluated recent papers that researched dietary protein sources to generate antidiabetic bioactive peptides/hydrolysates for the management of diabetes. Scopus and PubMed databases were searched to extract bibliometric data and, after a systematic four-step process was performed to select the articles, 75 papers were included in this review. The countries of origin of the authors who published the most were China (67%); Ireland (59%); and Spain (37%). The journals that published most articles on the subject were Food Chemistry (n = 12); Food & Function (n = 8); and Food Research International (n = 6). The most used keywords were ‘bioactive peptides’ (occurrence 28) and ‘antidiabetic’ (occurrence 10). The most used enzymes were Alcalase^® (17%), Trypsin (17%), Pepsin, and Flavourzyme^® (15% each). It was found that different sources of protein have been used to generate dipeptidyl peptidase IV (DPP-IV), α-amylase, and α-glucosidase inhibitory peptides. In addition to antidiabetic properties, some articles (n = 30) carried out studies on multifunctional bioactive peptides, and the most cited were reported to have antioxidant and antihypertensive activities (n = 19 and 17, respectively). The present review intended to offer bibliometric data on the most recent research on the production of antidiabetic peptides from dietary proteins to those interested in their obtention to act as hypoglycemic functional ingredients. The studies available in this period, compiled, are not yet enough to point out the best strategies for the production of antidiabetic peptides from food proteins and a more systematic effort in this direction is necessary to allow a future scale-up for the production of these possible functional ingredients.

Sprouting and Hydrolysis as Biotechnological Tools for Development of Nutraceutical Ingredients from Oat Grain and Hull

Oat consumption has increased during the last decade because of the health benefits associated with its soluble dietary fiber (β-glucan), functional proteins, lipids, and the presence of specific phytochemicals, such as avenanthramides. Oat is consumed mainly as whole grain, and the hull (seed coat), comprising 25–35% of the entire grain, is removed, generating a large amount of waste/by-product from the milling industry. The objective of this study was to evaluate the use of biotechnological strategies, such as sprouting for oat grain (OG) and hydrolysis for oat hull (OH), to enhance antioxidant and anti-inflammatory properties and lower the glycemic index (GI). Sprouting produced significant (p ≤ 0.05) increases in free (32.10 to 76.62 mg GAE (100 g)−1) and bound phenols (60.45 to 124.36 mg GAE (100 g)−1), increasing significantly (p ≤ 0.05) the avenanthramide (2c, 2p and 2f) soluble phenolic alkaloid content and anti-inflammatory properties of OG. On the other hand, the hydrolysis of OH using Viscoferm (EH2-OH) and Ultraflo XL (EH21-OH) increased by 4.5 and 5-fold the release of bound phenols, respectively; meanwhile, the use of Viscoferm increased the 4.55-fold soluble β-glucan content in OH, reaching values close to those of OG (4.04 vs. 4.46 g (100 g)−1). The study shows the potential of both strategies to enhance the nutritional and bioactive properties of OG and OH and describes these processes as feasible for the industry to obtain an ingredient with high antioxidant and anti-inflammatory activities. Single or combined biotechnological tools can be used on oat grains and hulls to provide nutraceutical ingredients.

Production, health-promoting properties and characterization of bioactive peptides from cereal and legume grains

The search for bioactive components for the development of functional foods and nutraceuticals has received tremendous attention. This is due to the increasing awareness of their therapeutic potentials, such as antioxidant, anti-inflammatory, antihypertensive, anti-cancer properties, etc. Food proteins, well known for their nutritional importance and their roles in growth and development, are also sources of peptide sequences with bioactive properties and physiological implications. Cereal and legume grains are important staples that are processed and consumed in various forms worldwide. However, they have received little attention compared to other foods. This review therefore is geared towards surveying the literature for an appraisal of research conducted on bioactive peptides in cereal and legume grains in order to identify what the knowledge gaps are. Studies on bioactive peptides from cereal and legume grains are still quite limited when compared to other food items and most of the research already carried out have been done without identifying the sequence of the bioactive peptides. However, the reports on the antioxidative, anticancer/inflammatory, antihypertensive, antidiabetic properties show there is much prospect of obtaining potent bioactive peptides from cereal and legume grains which could be utilized in the development of functional foods and nutraceuticals.

Legume Seed Protein Digestibility as Influenced by Traditional and Emerging Physical Processing Technologies

The increased consumption of legume seeds as a strategy for enhancing food security, reducing malnutrition, and improving health outcomes on a global scale remains an ongoing subject of profound research interest. Legume seed proteins are rich in their dietary protein contents. However, coexisting with these proteins in the seed matrix are other components that inhibit protein digestibility. Thus, improving access to legume proteins often depends on the neutralisation of these inhibitors, which are collectively described as antinutrients or antinutritional factors. The determination of protein quality, which typically involves evaluating protein digestibility and essential amino acid content, is assessed using various methods, such as in vitro simulated gastrointestinal digestibility, protein digestibility-corrected amino acid score (IV-PDCAAS), and digestible indispensable amino acid score (DIAAS). Since most edible legumes are mainly available in their processed forms, an interrogation of these processing methods, which could be traditional (e.g., cooking, milling, extrusion, germination, and fermentation) or based on emerging technologies (e.g., high-pressure processing (HPP), ultrasound, irradiation, pulsed electric field (PEF), and microwave), is not only critical but also necessary given the capacity of processing methods to influence protein digestibility. Therefore, this timely and important review discusses how each of these processing methods affects legume seed digestibility, examines the potential for improvements, highlights the challenges posed by antinutritional factors, and suggests areas of focus for future research.

Isolation of bioactive peptides and multiple nutraceuticals of antidiabetic and antioxidant functionalities through sprouting: Recent advances

The employment of proteases directly from enzymes or indirectly from microorganisms during fermentation for the purpose of proteolysis of food proteins has been the conventional trend for the derivation of bioactive peptides from food matrices. However, recent studies have shown that inherent protease enzymes can be activated for this activity for vegetable foods using the sprouting process. The benefits of ease of operation, and reduced processing costs are formidable advantages for the optimal consideration of this technique. On another note, the demand for functional foods with therapeutic health effects has increased in recent years. Globally, plant foods are perceived as dietetic choices bearing sufficient quantities of concomitant nutraceuticals. In this manuscript, the sprouting route for the isolation of peptides and glucosinolates, and for the enhancement of total phenolic contents, polyunsaturated fatty acid profiles, and other bioactive constituents was explored. Advances regarding the phytochemical transformations in the course of sprouting, the therapeutic functionalities, and microbiological safety concerns of vegetable sprouts are delineated. In addition, consumption of vegetable sprouts has been shown to be more efficient in supplying nutraceutical components relative to their unsprouted counterparts. Biochemical mechanisms involving the inhibition of digestive enzymes such as α-amylase, β-glucosidase, and dipeptidyl peptidase IV (DPP-IV), single electron transfer, and metal chelation, for impartation of health benefits, have been reported to occur from bioactive components isolated from vegetable sprouts. PRACTICAL APPLICATIONS: Sprouting initiates proteolysis of vegetable proteins for the release of bioactive peptides. Abiotic stresses can be used as elicitors during the sprouting process to achieve enhanced phytochemical profiles of sprouts. Sprouting is a relatively more convenient approach to the improvement of the health benefits of vegetable foods. Vegetable sprouts are potential for the management of metabolic syndrome disorders.

Antidiabetic bio-peptides of soft and hard wheat glutens

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Effect of enzyme purification techniques on kiwifruit extract and gluten peptides were investigated.

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Ammonium sulfate was the most efficient kiwifruit enzyme purification method.

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Ammonium sulfate based purified enzyme produced bio-active peptides (<1 kDa).

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The highest in vitro inhibitory activities was observed on gliadin based peptides.

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High Pro, Ser, and Asp contents of sub-fraction (P3) explain the inhibitory effects.

The effects of various purification techniques on kiwifruit enzyme characteristics (protease activity, kinetic parameters, and protein patterns) and production of wheat gluten bio-active peptides were investigated. The enzyme extract purified by ammonium sulfate precipitation method exhibited the highest protease activity (26), K_m (0.04 ± 0.002 mM), K_cat/K_m (40), and yield (96%). Using actinidin, the hard and soft wheat gluten subunit proteins produced antidiabetic inhibitory (α-glucosidase and α-amylase) peptides. The smallest M_w fraction of soft wheat gliadin peptide (<1 kDa) showed the highest inhibitory capacity against α-glucosidase (18.4 ± 0.7%) and α-amylase (53.3 ± 1.9%). The presence of high levels of amino acids with hydroxyl groups and proline in P3 sub-fraction had a critical role on α-glucosidase (47.2%) and α-amylase (71.2%) inhibitory activities. In conclusion, wheat gluten subunit peptides showed significant metabolic effects relevant to glucose and insulin control in vitro.

Integrated Evaluation of the Multifunctional DPP-IV and ACE Inhibitory Effect of Soybean and Pea Protein Hydrolysates

Nowadays, notwithstanding their nutritional and technological properties, food bioactive peptides from plant sources garner increasing attention for their ability to impart more than one beneficial effect on human health. Legumes, which stand out thanks to their high protein content, represent valuable sources of bioactive peptides. In this context, this study focused on the characterization of the potential pleotropic activity of two commercially available soybean (SH) and pea (PH) protein hydrolysates, respectively. Since the biological activity of a specific protein hydrolysate is strictly correlated with its chemical composition, the first aim of the study was to identify the compositions of the SH and PH peptides. Peptidomic analysis revealed that most of the identified peptides within both mixtures belong to storage proteins. Interestingly, according to the BIOPEP-UWM database, all the peptides contain more than one active motive with known inhibitory angiotensin converting enzyme (ACE) and dipeptidyl-dipeptidases (DPP)-IV sequences. Indeed, the results indicated that both SH and PH inhibit DPP-IV and ACE activity with a dose-response trend and IC50 values equal to 1.15 ± 0.004 and 1.33 ± 0.004 mg/mL, and 0.33 ± 0.01 and 0.61 ± 0.05 mg/mL, respectively. In addition, both hydrolysates reduced the activity of DPP-IV and ACE enzymes which are expressed on the surface of human intestinal Caco-2 cells. These findings clearly support that notion that SH and PH may represent new ingredients with anti-diabetic and hypotensive effects for the development of innovative multifunctional foods and/or nutraceuticals for the prevention of metabolic syndrome.

Bioactive Peptides: An Understanding from Current Screening Methodology

Bioactive peptides with high potency against numerous human disorders have been regarded as a promising therapy in disease control. These peptides could be released from various dietary protein sources through hydrolysis processing using physical conditions, chemical agents, microbial fermentation, or enzymatic digestions. Considering the diversity of the original proteins and the complexity of the multiple structural peptides that existed in the hydrolysis mixture, the screening of bioactive peptides will be a challenge task. Well-organized and well-designed methods are necessarily required to enhance the efficiency of studying the potential peptides. This article, hence, provides an overview of bioactive peptides with an emphasis on the current strategy used for screening and characterization methods. Moreover, the understanding of the biological activities of peptides, mechanism inhibitions, and the interaction of the complex of peptide–enzyme is commonly evaluated using specific in vitro assays and molecular docking analysis.

Antioxidant and alpha-glucosidase enzyme inhibitory properties of hydrolyzed protein and bioactive peptides of quinoa

The quinoa protein is gaining global attraction due to high content of gluten-free protein. It is a rich source of high-quality protein with all essential amino acids. The objective of this study was to evaluate the antioxidant activity and alpha-glucosidase inhibition effect of bioactive peptides obtained from quinoa protein that was hydrolyzed by alcalase and trypsin. Peptides were fractionated using ultrafiltration with MW cut-off = 3, 10 kDa. The peptide concentration was evaluated using OPA solution and peptide bonds were studied by SDS-PAGE. The highest antioxidant activity obtained from quinoa bioactive peptides by alcalase and trypsin was observed after 0.5 h (10 kDa≤) and 4 h (3 kDa≥), respectively. The highest α-glucosidase inhibition activity was observed in peptides with MW 3 kDa ≥ when hydrolyzed by trypsin. The amino acid composition of the most effective samples has been determined. Comparing the results showed that MW and the composition of peptides influenced the studied traits. From the result of this study, it concluded that bioactive peptides obtained from quinoa protein could be used in functional food and supplements formulation.

Preparation and Antioxidant Properties of Germinated Soybean Protein Hydrolysates

In this study, soybeans during different germination stages were described and compared with regard to morphology, water content, protein, amino acids, and isoflavones. The optimal conditions for the hydrolysis of proteins obtained from germinated soybeans were determined using the response surface methodology. Gel filtration chromatography was used to separate germinated soybean protein hydrolysates after ultrafiltration, whereas 2,2-Diphenyl-1-picrylhydrazyl (DPPH), ABTS^•+, and FRAP assays were used to assess the antioxidant activity of different fractions. Findings of this study revealed that protein and isoflavone contents were high in soybean at 24 h following germination (the bud was about 0.5–1 cm). The proteins from germinated soybeans were hydrolyzed and separated into five fractions (G1–G5) and evaluated in terms of their molecular weight and antioxidant activity. Interestingly, the antioxidant activity was found to be higher in germinated soybean protein hydrolysates than in other soybean protein hydrolysates derived from soybean meal protein. This suggests that germination can effectively improve the utilization rate of soybean proteins. The antioxidant activity of G3 was best among G1–G5. The results obtained in this study demonstrate that germination for 24 h when the bud length is about 0.5–1 cm can be applied as a special pretreatment of plant seeds in the development of germinated foods. These findings can be used to identify the structure of the potential antioxidative hydrolysates for their possible exploitation in functional foods.

Screening and bioavailability evaluation of anti-oxidative selenium-containing peptides from soybeans based on specific structures

Our previous study has evaluated the antioxidant capacity and identified the sequences of soybean selenium-containing peptides. Herein, pharmacophore screening, gastrointestinal simulation and in vivo pharmacokinetics were performed to predict the potentials of selenium-containing peptides in terms of antioxidant activity, safety and bioavailability. A pharmacophore model with 6 structure features was constructed for virtual screening to determine the potential activities of 85 selenium sequences from soybean peptides. Strong reversing effects (p < 0.05) of the targeted sequences were observed in tumor necrosis factor-α (TNF-α)-induced inflammatory cytokines and adhesion factors burst in EA·hy926/Caco-2 co-culture cell models. Ser-Phe-Gln-SeMet (SFQSeM), a promising peptide selected from both virtual screening and cell models, was proved to be stable in the gastrointestinal tract and could be transported across the Caco-2 monolayer via the paracellular pathway. Additionally, SFQSeM showed a long residence time (89.42 ± 1.34 min) and half-life (81.60 ± 11.88 min) after consumption, and it induced lower liver alanine/aspartate transaminase (ALT/AST) and serum nitric oxide (NO) levels compared to Na2SeO3 and SeMet (p < 0.05). The potency of SFQSeM against oxidative stress as well as its oral bioavailability and low risk highlight its potential utility as an effective Se nutritional supplement.

The Association between Consumption of Dairy-Originated Digestion Resistant and Bioactive Peptides and Breast Cancer Risk: A Case-Control Study

Bioactive peptides (BPs) content of dairy products is suggested to be a significant ingredient for reducing breast cancer (BC) risk. There is no observational study regarding the correlation between BPs and the risk of chronic disease because BPs' content of food items has not been evaluated in any study. The goal of the current study was to assess the association of dairy-originated BPs with BC risk. One hundred thirty-four women with BC and 267 cancer-free controls were selected from referral hospitals in Tehran, Iran. The development of an in-silico model for estimation of the bioactive and digestion-resistant peptides content of dairy products was done in our previous research. The risk assessment for BPs and BC association was performed across the tertiles of the peptide's intake. Odds ratios (OR) were calculated by logistic regression. The negative association of all bioactive and digestion-resistant peptides except for peptides with high hydrophilicity and low bioactivity was seen in all models. In PR-negative subjects only the association of total dairy intake (OR: 0.61; 95% CI: 0.26-1.45; P _{for trend}: 0.276), peptides with low bioactivity (OR: 0.40; 95% CI: 0.16-1.02; P _{for trend}: 0.0.052), antidiabetic peptides (OR: 0.42; 95% CI: 0.17-1.05; P _{for trend}: 0.0.062) and di-peptides (OR: 0.42; 95% CI: 0.17-1.05; P _{for trend}: 0.0.062) were not significant in the final model. Also, no significant association between ER-negative subjects and total dairy intake (OR: 0.41; 95% CI: 0.16-1.07; P _{for trend}: 0.0.068) was noted. Our findings deduced that milk-derived BPs negatively associate with the risk of ER/PR/HER2 negative BC among Iranian women.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.2009884.

Antidiabetic potential of soy protein/peptide: A therapeutic insight

Soybean (Glycine max) harbours high quality proteins which have been evident to exhibit therapeutic properties in alleviating many diseases including but not limited to diabetes and its related metabolic complications. Since diabetes is often manifested with hyperglycemia, impaired energy homeostasis and even low-grade chronic inflammation, plenty of information has raised the suggestion for soy protein supplementation in preventing and controlling these abnormalities. Moreover, clinical intervention studies have established a noteworthy correlation between soy protein intake and lower prevalence of diabetes. Besides soy protein, various soy-derived peptides also have been found to trigger antidiabetic response in different in vitro and in vivo models. Molecular mechanisms underlying the antidiabetic actions of soy protein and peptide have been predicted in many literatures. Results demonstrate that components of soy protein can act in diversified ways and modulate various cell signaling pathways to bring energy homeostasis and to regulate inflammatory parameters associated with diabetic pathophysiology. The main objective of the present review lies in a systemic understanding of antidiabetic role of soy protein and peptide in the context of impaired glucose and lipid metabolism, and inflammation.

The novel homologue of the human α-glucosidase inhibited by the non-germinated and germinated quinoa protein hydrolysates after in vitro gastrointestinal digestion

Quinoa (Chenopodium quinoa Willd) is a potential source of protein with ideal amino acid profiles which its bioactive compounds can be improved during germination and gastrointestinal digestion. The present investigation studies the impact of germination for 24 hr and simulated gastrointestinal digestion on α-glucosidase inhibitory activity of the quinoa protein and bioactive peptides against the novel homologue of human α-glucosidase, PersiAlpha-GL1. The sprouted quinoa after gastroduodenal digestion was the most effective α-glucosidase inhibitor showing 81.10% α-glucosidase inhibition at concentration 4 mg/ml with the half inhibition rate (IC₅₀ ) of 0.07 mg/ml. Based on the kinetic analysis, both the germinated and non-germinated samples before and after digestion were competitive-type inhibitors of α-glucosidase. Results of this study showed the improved α-glucosidase inhibitory activity of the quinoa bioactive peptides after germination and gastrointestinal digestion and highlighted the potential of metagenome-derived PersiAlpha-GL1 as a novel homologue of the human α-glucosidase for developing the future anti-diabetic drugs. PRACTICAL APPLICATIONS: This study aimed to evaluate the effect of germination and gastrointestinal digestion of the quinoa protein and bioactive peptides on α-glucosidase inhibitory activity against the novel PersiAlpha-GL1. Metagenomic data were used to identify the novel α-glucosidase structurally and functionally homologue of human intestinal. The results showed the highest inhibition on PersiAlpha-GL1 by a germinated quinoa after gastroduodenal digestion and confirmed the potential of PersiAlpha-GL1 to enhance the effectiveness of the anti-diabetic drugs for industrial application.

Production, Purification, and Potential Health Applications of Edible Seeds' Bioactive Peptides: A Concise Review

Edible seeds play a significant role in contributing essential nutritional needs and impart several health benefits to improve the quality of human life. Previous literature evidence has confirmed that edible seed proteins, their enzymatic hydrolysates, and bioactive peptides (BAPs) have proven and potential attributes to ameliorate numerous chronic disorders through the modulation of activities of several molecular markers. Edible seed-derived proteins and peptides have gained much interest from researchers worldwide as ingredients to formulate therapeutic functional foods and nutraceuticals. In this review, four main methods are discussed (enzymatic hydrolysis, gastrointestinal digestion, fermentation, and genetic engineering) that are used for the production of BAPs, including their purification and characterization. This article’s main aim is to provide current knowledge regarding several health-promoting properties of edible seed BAPs in terms of antihypertensive, anti-cancer, antioxidative, anti-inflammatory, and hypoglycemic activities.

Characteristics of Food Protein-Derived Antidiabetic Bioactive Peptides: A Literature Update

Diabetes, a glucose metabolic disorder, is considered one of the biggest challenges associated with a complex complication of health crises in the modern lifestyle. Inhibition or reduction of the dipeptidyl peptidase IV (DPP-IV), alpha-glucosidase, and protein-tyrosine phosphatase 1B (PTP-1B) enzyme activities or expressions are notably considered as the promising therapeutic strategies for the management of type 2 diabetes (T2D). Various food protein-derived antidiabetic bioactive peptides have been isolated and verified. This review provides an overview of the DPP-IV, PTP-1B, and α-glucosidase inhibitors, and updates on the methods for the discovery of DPP-IV inhibitory peptides released from food-protein hydrolysate. The finding of novel bioactive peptides involves studies about the strategy of separation fractionation, the identification of peptide sequences, and the evaluation of peptide characteristics in vitro, in silico, in situ, and in vivo. The potential of bioactive peptides suggests useful applications in the prevention and management of diabetes. Furthermore, evidence of clinical studies is necessary for the validation of these peptides’ efficiencies before commercial applications.