Bioactive properties of peptides obtained from Argentinian defatted soy flour protein by Corolase PP hydrolysis

Soybean meal peptide Gly-Thr-Tyr-Trp could protect mice from acute alcoholic liver damage: A study of protein-protein interaction and proteomic analysis

Alcoholic liver disease (ALD) is a serious health threat. Soybean meal peptide (SMP) supplementation may protect against this damage; however, the potential mechanism underlying the specific sequence of SMPs is unclear. Protein-protein interaction and proteomic analyses are effective methods for studying functional ingredients in diseases. This study aimed to investigate the potential mechanism of action of the peptide Gly-Thr-Tyr-Trp (GTYW) on ALD using protein-protein interaction and proteomic analyses. These results demonstrate that GTYW influenced the targets of glutathione metabolism (glutathione-disulfide reductase, glutathione S-transferase pi 1, and glutathione S-transferase mu 2). It also regulated the expression of targets related to energy metabolism and amino acid conversion (trypsin-2, cysteine dioxygenase type-1, and F6SJM7). Amino acid and lipid metabolisms were identified based on Gene Ontology annotation. These results indicate that GTYW might affect alcohol-related liver disease signaling pathways. This study provides evidence of the protective and nutritional benefits of SMPs in ALD treatment.

The zinc absorption of the novel peptide-Zn complex in Caco-2 cells: effects of soybean peptides charge and hydrophobicity

BACKGROUND

The supplemental effect of zinc depends not only on adequate intake, but also on how efficiently it is absorbed in the small intestine. In the present study, weak hydrophobic peptides (WHP), strong hydrophobic peptides (SHP), positively charged peptides (PCP) and negatively charged peptides (NCP) were isolated from soybean peptides (SP). The peptide-Zn complexes (PCP-Zn, NCP-Zn, WHP-Zn, SHP-Zn and SP-Zn) were prepared to compare their promotion zinc absorption capacity in the Caco-2 cells monolayers model.

RESULTS

We found that the carboxyl, carbonyl and amino groups in peptide were the primary binding sites of Zn. Compared with zinc sulfate, the peptide-Zn complexes with different charge and hydrophobic peptides could improve zinc solubility at different pH. NCP-Zn had a lower Zn-binding capacity but a higher zinc absorption capacity compared to that of PCP-Zn in Caco-2 cells. In addition, the capacity of PCP-Zn to promote zinc absorption was lower than the control group (SP-Zn). There were no significant differences in transport rates, retention rates and uptake rates of WHP-Zn, SHP-Zn and SP-Zn. NCP-Zn could improve the activity of Zn-related enzymes, and the expression levels of PepT1 and ZnT1 were higher than other peptide-Zn complexes.

CONCLUSION

The promotion zinc absorption capacity of peptide-Zn complexes was not completely dependent on the Zn-binding capacity, but also depended on the charge and hydrophobicity of peptides. © 2024 Society of Chemical Industry.

Streptococcus thermophilus: A Source of Postbiotics Displaying Anti-Inflammatory Effects in THP 1 Macrophages

In addition to traditional use in fermented dairy products, S. thermophilus also exhibits anti-inflammatory properties both in live and heat-inactivated form. Recent studies have highlighted that some hydrolysates from surface proteins of S. thermophilus could be responsible partially for overall anti-inflammatory activity of this bacterium. It was hypothesized that anti-inflammatory activity could also be attributed to peptides resulting from the digestion of intracellular proteins of S. thermophilus. Therefore, total intracellular proteins (TIP) from two phenotypically different strains, LMD-9 and CNRZ-21N, were recovered by sonication followed by ammonium sulphate precipitation. The molecular masses of the TIP of both strains were very close to each other as observed by SDS-PAGE. The TIP were fractionated by size exclusion fast protein liquid chromatography to obtain a 3-10 kDa intracellular protein (IP) fraction, which was then hydrolysed with pancreatic enzyme preparation, Corolase PP. The hydrolysed IP fraction from each strain exhibited anti-inflammatory activity by modulating pro-inflammatory mediators, particularly IL-1β in LPS-stimulated THP-1 macrophages. However, a decrease in IL-8 secretion was only observed with hydrolysed IP fraction from CNRZ-21N, indicating that strain could be an important parameter in obtaining active hydrolysates. Results showed that peptides from the 3-10 kDa IP fraction of S. thermophilus could therefore be considered as postbiotics with potential beneficial effects on human health. Thus, it can be used as a promising bioactive ingredient for the development of functional foods to prevent low-grade inflammation.

Current state of insect proteins: extraction technologies, bioactive peptides and allergenicity of edible insect proteins

This review aims to provide an updated overview of edible insect proteins and the bioactivity of insect-derived peptides. The essential amino acid content of edible insects is compared with well-known protein sources to demonstrate that edible insects have the potential to cover the protein quality requirements for different groups of the population. Then the current methodologies for insect protein extraction are summarized including a comparison of the protein extraction yield and the final protein content of the resulting products for each method. Furthermore, in order to improve our understanding of insect proteins, their functional properties (such as solubility, foaming capacity, emulsifying, gelation, water holding capacity and oil holding capacity) are discussed. Bioactive peptides can be released according to various enzymatic hydrolysis protocols. In this context, the bioactive properties of insect peptides (antihypertensive, antidiabetic, antioxidant and anti-inflammatory properties) have been discussed. However, the allergens present in insect proteins are still a major concern and an unsolved issue for insect-based product consumption; thus, an analysis of cross reactivity and the different methods available to reduce allergenicity are proposed. Diverse studies of insect protein hydrolysates/peptides have been ultimately promoting the utilization of insect proteins for future perspectives and the emerging processing technologies to enhance the wider utilization of insect proteins for different purposes.

Recent advances in exploring and exploiting soybean functional peptides-a review

Soybeans are rich in proteins and phytochemicals such as isoflavones and phenolic compounds. It is an excellent source of peptides with numerous biological functions, including anti-inflammatory, anticancer, and antidiabetic activities. Soy bioactive peptides are small building blocks of proteins that are released after fermentation or gastrointestinal digestion as well as by food processing through enzymatic hydrolysis, often in combination with novel food processing techniques (i.e., microwave, ultrasound, and high-pressure homogenization), which are associated with numerous health benefits. Various studies have reported the potential health benefits of soybean-derived functional peptides, which have made them a great substitute for many chemical-based functional elements in foods and pharmaceutical products for a healthy lifestyle. This review provides unprecedented and up-to-date insights into the role of soybean peptides in various diseases and metabolic disorders, ranging from diabetes and hypertension to neurodegenerative disorders and viral infections with mechanisms were discussed. In addition, we discuss all the known techniques, including conventional and emerging approaches, for the prediction of active soybean peptides. Finally, real-life applications of soybean peptides as functional entities in food and pharmaceutical products are discussed.

Multi-dimensional analysis of heat-induced soybean protein hydrolysate gels subjected to ultrasound-assisted pH pretreatment

This study aimed to evaluate the gelation characteristics of soybean protein hydrolysate (SPH) extracted by enzyme-assisted aqueous extraction. Specifically, the changes in gelation behaviors for heat-induced (95 °C, 20 min) SPH dispersions treated with pH (pH 3, 5, 9; pH 7 as control) and ultrasound (U; 240 W, 30 min) were investigated. The results showed that typical gel behavior with high elastic nature in the viscoelasticity and network structures were observed during the heating process, where the disulfide bond played a dominant role in the gel network formation of all the samples. Notably, the heat-induced aggregation in the SPH gels was mainly formed by the association of the basic B polypeptide in 11S and β subunit in 7S. The most superior SPH gel was formed at pH 7 when assisted by ultrasonication during the heating process. This as-synthesized gel showed a uniform filamentous structure and exhibited the more excellent textural, rheological and thermal properties than those of the samples formed under acidic and alkaline conditions. These results are of great value in revealing the gelation mechanism of SPH.

Metal-chelating activity of soy and pea protein hydrolysates obtained after different enzymatic treatments from protein isolates

Soy and pea proteins are two rich sources of essential amino acids. The hydrolysis of these proteins reveals functional and bioactive properties of the produced small peptide mixtures. In our study, we employed the hydrolysis of soy and pea protein isolates with the endopeptidases Alcalase® and Protamex®, used alone or followed by the exopeptidase Flavourzyme®. The sequential enzyme treatments were the most efficient regarding the degree of hydrolysis. Then, soy and pea protein hydrolysates (SPHs and PPHs, respectively) were ultrafiltrated in order to select peptides of molecular weight ≤ 1 kDa. Whatever the protein source or the hydrolysis treatment, the hydrolysates showed similar molecular weight distributions and amino acid compositions. In addition, all the ultrafiltrated hydrolysates possess metal-chelating activities, as determined by UV-spectrophotometry and Surface Plasmon Resonance (SPR). However, the SPR data revealed better chelating affinities in SPHs and PPHs when produced by sequential enzymatic treatment.

Impact of Different Enzymatic Processes on Antioxidant, Nutritional and Functional Properties of Soy Protein Hydrolysates Incorporated into Novel Cookies

Soy protein concentrate (SPC) was hydrolyzed using several commercial food-grade proteases (Alcalase, Neutrase, papain, Everlase, Umamizyme, Flavourzyme) and their combination to obtain promising ingredients in the manufacture of functional bakery products. In all cases, the hydrolysis caused nutritional, sensory, and rheological changes in SPC, as well as protein structural changes like increased surface hydrophobicity and content of exposed SH groups with the magnitude of these changes depending on enzyme specificity. The hydrolysis with the combination of Neutrase and Flavourzyme (NeuFlav) increased essential amino acid content by 9.8% and that of Lys by 32.6% compared to SPC. This hydrolysate showed also significant antioxidant activities including ABTS and superoxide anion scavenging activity and metal-chelating ability. The addition of all hydrolysates in wheat flour decreased water adsorption and increased development time to some extent due to gluten network weakening, but also decreased the rate of starch retrogradation, contributing to the increase of the shelf-life of bakery products. The NeuFlav tasted less bitter than other hydrolysates, while E-nose provided a discrimination index of 93 between control and hydrolysates. It appeared that the addition of the NeuFlav hydrolysate in a cookie formulation improved protein content and nutritional quality and directed to its higher general consumer acceptability than cookies formulated with only wheat flour.

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.

Acetylcholinesterase and butyrylcholinesterase inhibitory activities of antioxidant peptides obtained from enzymatic pea protein hydrolysates and their ultrafiltration peptide fractions

This study optimized the enzymatic hydrolysis of yellow field pea proteins using alcalase (ACH), chymotrypsin (CHH), flavourzyme (FZH), pancreatin (PCH), pepsin (PEH), and trypsin (TPH) to obtain hydrolysates and ultrafiltered fractions (<1, 1-3, 3-5 and 5-10 kDa) that possess antioxidant plus acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities. The hydrolysates exhibited varying degrees of radical scavenging and inhibition of linoleic acid peroxidation, as well as cholinesterase inhibition activities but the potency generally improved by >10% after UF separation into peptide fractions. ACH, FZH, and PEH exhibited significantly (p < .05) higher (20%-30% increases) radical scavenging activities than the other hydrolysates. The 1 and 3 kDa UF fractions of ACH, FZH, and PEH inhibited ~20%-30% AChE activity, while ACH, PCH, TPH, and PEH inhibited ~20%-40% BuChE activity. We conclude that the pea protein hydrolysates and their peptide fractions possess multifunctional properties with potential use against neurodegenerative disorders. PRACTICAL APPLICATIONS: Alzheimer's disease (AD) has multiple pathological pathways in addition to the loss of acetylcholine (ACh) catalyzed by acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The presence of severe oxidative stress triggered by lipid peroxidation and formation of free radicals is a common trait in AD patients. The concept of AChE and BuChE inhibition as an approach toward AD amelioration involves the use of compounds with a similar structure to ACh, the natural substrate. Peptides derived from food proteins consist of ester bonds with structural similarity to ACh and theoretically possess the ability to interact with AChE and BuChE. Results from the present study imply that pea protein-derived peptides are potential candidates for use as inhibitors of AChE and BuChE activities, with application in the prevention and management of AD.

Hydrolysis of Soybean Milk Protein by Papain: Antioxidant, Anti-Angiotensin, Antigenic and Digestibility Perspectives

The objective of the investigation was to understand the biochemical activities of hydrolysate of soybean milk protein (SMP). Hydrolysis was carried out by different concentrations of papain (0.008 g·L⁻¹, 0.016 g·L⁻¹, 0.032 g·L⁻¹ and 0.064 g·L⁻¹). The antioxidant capacity was measured by the ferric-reducing ability of plasma (FRAP) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assays. The anti-angiotensin activity of hydrolysate was measured by the recombinant angiotensin converting enzyme and substrate Abz-FRK(Dnp)-P. The contributions of the Kunitz trypsin inhibitor (KTI) and Bowman–Birk inhibitor (BBI) on antigenicity, and the in vitro digestion of papain-hydrolyzed SMP were studied. Rabbit polyclonal anti-KTI and anti-BBI antibodies together with peroxidase-labelled goat anti-Rb IgG secondary antibody were used to identify the antigenicity of KTI and BBI in unhydrolyzed and papain-hydrolyzed SMP. The antioxidant capacity and anti-angiotensin activity of SMP were increased after the papain hydrolysis of SMP. The KTI- and BBI-specific antigenicity were reduced in SMP by increasing the concentration of papain. However, there was interaction between papain-hydrolyzed SMP and trypsin in native gel, while interaction with chymotrypsin was absent. The interaction between trypsin and SMP was reduced due to the hydrolysis of papain in a concentration-dependent manner. According to the in vitro gastrointestinal digestion simulation protocol (Infogest), the digestibility of SMP was not statistically increased.

Bioactive Hydrolysates from Chlorella vulgaris: Optimal Process and Bioactive Properties

Microalgae have been described as a source of bioactive compounds, such as peptides. Microalgae are easy to produce, making them a sustainable resource for extracting active ingredients for industrial applications. Several microalgae species have interesting protein content, such as Chlorella vulgaris with around 52.2% of protein, making it promising for peptide hydrolysate production. Therefore, this work focused on the production of water-soluble hydrolysates rich in proteins/peptides from the microalgae C. vulgaris and studied bioactive properties. For that, a design of experiments (DOE) was performed to establish the optimal conditions to produce hydrolysates with higher levels of protein, as well as antioxidant and antihypertensive properties. Four experimental factors were considered (cellulase percentage, protease percentage, hydrolysis temperature, and hydrolysis duration) for three responses (protein content, antioxidant activity, and antihypertensive activity). The optimal conditions determined by the DOE allowed producing a scaled-up hydrolysate with 45% protein, with antioxidant activity, measured by oxygen radical absorbance capacity assay, of 1035 µmol TE/g protein, IC50 for angiotensin-converting enzyme inhibition activity of 286 µg protein/mL, and α-glucosidase inhibition of 31% (30 mg hydrolysate/mL). The obtained hydrolysates can be used as functional ingredients for food and nutraceuticals due to their antioxidant, antihypertensive, and antidiabetic potential. Moreover, the antioxidant potential of the extracts may be relevant for the cosmetic industry, especially in antiaging formulations.

Differences in the gut microbiota composition of rats fed with soybean protein and their derived peptides

Current studies regarding the effect of different nitrogen sources on gut microbiota have thus far disregarded the ability of probiotics and coliforms to compete for protein. This study aimed to investigate the differences in the utilization of soybean protein (SPro) and its derived peptides (SPep) by the gut microbiota of Sprague Dawley (SD) rats. The SPro and SPep prepared in this study showed extensive SPro molecular weight distribution, while that of SPep was minimal, ranging between 150 and 1000 Da and primarily consisting of two to five amino acids. The cecum microflora composition of the rats was determined via 16S rDNA amplicon sequencing, showing that the SPro and SPep significantly increased the abundance and uniformity of the gut microbiota after 35 days of feeding. The Firmicutes/Bacteroidetes (F/B) ratios of the SPep, SPro, and casein groups were 2.49 ± 0.60, 2.98 ± 1.12, and 2.59 ± 0.74, respectively. Although the rats fed with SPro and SPep displayed similar gut microbiome structures, SPep significantly promoted Lactobacillus and Phascolarctobacterium growth. The results showed that SPep significantly increased the diversity of the gut microbiota and elevated the probiotic proportion. PRACTICAL APPLICATION: SPro and SPep are two nutritious and high-quality nitrogen sources. The results showed that SPro and SPep regulated the structure of gut microbiota in rats, and the effect of SPep was better. This study provides a theoretical basis for developing SPep functional foods able to regulate gut microbiota and maintain health.

An evidence of microalgal peptides to target spike protein of COVID-19: In silico approach

The outbreak of the novel coronavirus (COVID-19) has affected millions of lives and it is one of the deadliest viruses ever known and the effort to find a cure for COVID-19 has been very high. The purpose of the study was to investigate the anti-COVID effect from the peptides derived from microalgae. The peptides from microalgae exhibit antimicrobial, anti-allergic, anti-hypersensitive, anti-tumor and immune-modulatory properties. In the In silico study, 13 cyanobacterial specific peptides were retrieved based on the extensive literature survey and their structures were predicted using Discovery Studios Visualizer. The spike protein of the novel COVID19 was retrieved from PDB (6LU7) and further molecular docking was done with the peptides through CDOCKER. The five peptides were bound clearly to the spike protein (SP) and their inhibitory effect towards the SP was promising among 13 peptides were investigated. Interestingly, LDAVNR derived from S.maxima have excellent binding and interaction energy showed -113.456 kcal/mol and -71.0736 kcal/mol respectively to target SP of COVID. The further investigation required for the in vitro confirmation of anti-COVID from indigenous microalgal species for the possible remedy in the pandemic.

Collagen-Based Bioactive Bromelain Hydrolysate from Salt-Cured Cod Skin

Considerable amounts of fish processing by-products are discarded each year. About 30% of this material may be skin and bone. Fish skin has more than 80% of its total protein content as collagen. Furthermore, in recent years, there has been a growing demand for collagen-based peptides due to their beneficial health effects. So, the objective of the present study was to optimise the obtaining bioactive hydrolysates from salt-cured cod skin using the protease Bromelain at 0.5% (w/w) concentration. This study developed a sustainable process that consumes less time and energy and uses an alternative source as raw material. In addition, bromelain allows hydrolysates with important antioxidant (ORAC, 514 μmol Trolox Equivalent/g protein) and antihypertensive activities (inhibition of ACE, IC50 of 166 μg protein/mL) as well as excellent biocompatibility with dermal and subcutaneous cells.

Hydrolysate from Mussel Mytilus galloprovincialis Meat: Enzymatic Hydrolysis, Optimization and Bioactive Properties

Mussel production generates losses and waste since their commercialisation must be aligned with target market criteria. Since mussels are rich in proteins, their meat can be explored as a source of bioactive hydrolysates. Thus, the main objective of this study was to establish the optimal production conditions through two Box–Behnken designs to produce, by enzymatic hydrolysis (using subtilisin and corolase), hydrolysates rich in proteins and with bioactive properties. The factorial design allowed for the evaluation of the effects of three factors (hydrolysis temperature, enzyme ratio, and hydrolysis time) on protein/peptides release as well as antioxidant and anti-hypertensive properties of the hydrolysates. The hydrolysates produced using the optimised conditions using the subtilisin protease showed 45.0 ± 0.38% of protein, antioxidant activity via ORAC method of 485.63 ± 60.65 µmol TE/g of hydrolysate, and an IC₅₀ for the inhibition of ACE of 1.0 ± 0.56 mg of protein/mL. The hydrolysates produced using corolase showed 46.35 ± 1.12% of protein, antioxidant activity of 389.48 ± 0.21 µmol TE/g of hydrolysate, and an IC₅₀ for the inhibition of ACE of 3.7 ± 0.33 mg of protein/mL. Mussel meat losses and waste can be used as a source of hydrolysates rich in peptides with relevant bioactive properties, and showing potential for use as ingredients in different industries, such as food and cosmetics, contributing to a circular economy and reducing world waste.

Non-animal proteins as cutting-edge ingredients to reformulate animal-free foodstuffs: Present status and future perspectives

Consumer interest in protein rich diets is increasing, with more attention being paid to the protein source. Despite the occurrence of animal proteins in the human diet, non-animal proteins are gaining popularity around the world due to their health benefits, environmental sustainability, and ethical merit. These sources of protein qualify for vegan, vegetarian, and flexitarian diets. Non-animal proteins are versatile, derived mainly from cereals, vegetables, pulses, algae (seaweed and microalgae), fungi, and bacteria. This review's intent is to analyze the current and future direction of research and innovation in non-animal proteins, and to elucidate the extent (limitations and opportunities) of their applications in food and beverage industries. Prior knowledge provided relevant information on protein features (processing, structure, and techno-functionality) with particular focus on those derived from soy and wheat. In the current food landscape, beyond conventionally used plant sources, other plant proteins are gaining traction as alternative ingredients to formulate animal-free foodstuffs (e.g., meat alternatives, beverages, baked products, snack foods, and others). Microbial proteins derived from fungi and algae are also food ingredients of interest due to their high protein quantity and quality, however there is no commercial food application for bacterial protein yet. In the future, key points to consider are the importance of strain/variety selection, advances in extraction technologies, toxicity assessment, and how this source can be used to create food products for personalized nutrition.

Pepsin Hydrolysis of Orange By-Products for the Production of Bioactive Peptides with Gastrointestinal Resistant Properties

Recently, the use of bioactive compounds in improving human health has received more attention. The aim of the present study was to hydrolyze orange seed proteins using pepsin enzyme to obtain bioactive peptides as well as to study the stability of such activity after simulated gastrointestinal digestion conditions. The method was optimized using different enzyme concentrations from 1% to 3%, hydrolysis times between 2 and 5 h, and an optimal temperature of 33 °C. Biological activities including α-glucosidase inhibition, α-amylase inhibition, Angiotensin I-Converting Enzyme (ACEI) inhibition, ferric reducing antioxidant power, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity were evaluated. According to the results, a significant higher value of the biological activity (p < 0.05) was observed using an enzyme ratio of 0.03 E/S and hydrolysis time of 3.5 h. After size-exclusion chromatography separation, fractions 45–49 and 50–54 showed the highest biological roles such as antioxidant, ACEI inhibitory, and hypoglycemic. Fractions with the highest biological activity were purified using RP-HPLC and analyzed using nano-liquid chromatography and mass spectrometry. The results obtained after simulated gastrointestinal digestion indicated that peptide fractions obtained after chromatographic separation significantly maintain their activity.

Functional characterisation and sensory evaluation of a novel synbiotic okara beverage

This study aimed to produce four different beverages from okara (soybean by-product) previously hydrolyzed by Cynara cardunculus enzymes and fermented by probiotic bacteria or unfermented beverage. The probiotic viable cells, the isoflavones profile and organic acids were evaluated in the okara beverage. In addition, total phenolic content, antioxidant and ACE inhibitory activities were evaluated at storage time and during in vitro gastrointestinal digestion of all beverages. The probiotic was viable throughout storage in all fermented beverages. The significant bioconversion of the isoflavone glycosides into their corresponding bioactive aglycones was observed in fermented beverage. Furthermore, the beverages showed a good ACE inhibitory activity. After gastrointestinal tract, all beverages showed an increase in the antioxidant and ACE inhibitory activities. In conclusion, this study shows that the application of okara for a multifunctional beverage could be a promising strategy in the disease prevention and contribution to a zero waste approach in food industry.

Processed by-Products from Soy Beverage (Okara) as Sustainable Ingredients for Nile Tilapia (O. Niloticus) Juveniles: Effects on Nutrient Utilization and Muscle Quality

Simple Summary

The consumption of soy products increases worldwide and generates large amounts of by-products, which are often discarded. Okara is a soybean by-product with high nutritional value. This work evidenced the great potential of okara meal, after appropriate technological processing, to be used as feed ingredient in Nile tilapia diets. It was clearly demonstrated the effectiveness of the autoclave and the use of proteases from C. cardunculus without fermentation to increase okara nutrient bioavailability. The inclusion of up to 20% okara meal in diets for tilapia did not affect growth performance, nutrient utilization, or whole body composition compared to a reference diet. Flesh quality remained largely unaffected, although fish fed with AOK diets had the highest density of muscle fibers.

Abstract

The apparent digestibility coefficients (ADCs) of differently processed okara meals were assessed in Nile tilapia diets: dried okara not autoclaved (FOK), dried okara autoclaved (AOK), okara hydrolyzed with Alcalase (ALOK) or Cynara cardunculus proteases (CYOK), and hydrolyzed okara fermented with lactic bacteria: Lactobacillus rhamnosus R11 (CYR11OK) or Bifidobacterium animalis ssp. lactis Bb12 (CYB12OK). Okara processing significantly affected nutrient digestibility: dry matter ADC was highest in CYR11OK (80%) and lowest in FOK (40%). The lowest protein digestibility was observed in CYR11OK (72%), and the highest in AOK (97%) and CYOK (91%), evidencing the effectiveness of the autoclave and the use of C. cardunculus proteases to increase okara protein bioavailability. The inclusion of up to 20% of AOK or CYOK did not affect fish growth, nutrient utilization, or whole body composition of Nile tilapia. The flesh quality (color, pH, water activity, cohesiveness, elasticity and resilience) was not affected by the dietary incorporation of AOK or CYOK. Fish fed with AOK diets stand out for their high density of muscle fibers, particularly in AOK20, which can explain their high muscle firmness and may result in further hypertrophic growth. Altogether, results suggest that hydrolyzed or autoclaved okara are valuable ingredients for Nile tilapia diets.

Soy bioactive peptides and the gut microbiota modulation

The balance of protein, carbohydrate, and fat affect the composition and functions of the gut microbiota. The complexities involved thereof require insights into the roles and impacts of individual dietary components due to the difficulty of defining such in a group of others. Peptides and proteins from several animal and plant sources have been widely explored in relation to the gut microbiome modulation, but the effects of soy peptides and other soy derivatives on the gut microbiota are largely unexplored. This piece considered an overview of the production and interventions of soy bioactive peptides on gut, as they affect the composition and functions of the gut microorganisms. A mini review on the production of soy protein hydrolysates/peptides and highlights of the most recent knowledge regarding their physiological effects on host's gut microbiota cum health were investigated. Overall deductions and research gaps were critically evaluated for futuristic interventions and relevance. Key points • Diet affects the composition of gut microorganisms. • Modulation of the gut microbiota by soy biopeptides is described. • Critical deductions on personal and commercial use are provided.

Impact of Simulated Gastrointestinal Digestion on the Biological Activity of an Alcalase Hydrolysate of Orange Seed (Siavaraze, Citrus sinensis) by-Products

In this study, orange seed proteins were hydrolyzed by Alcalase enzyme at different enzyme concentrations 1-3% (v/w) and hydrolysis times (2-5 h), to obtain bioactive peptides showing antioxidant, Angiotensin-converting enzyme (ACE) -inhibitory, and hypoglycemic activities. The highest biological activities (p < 0.05) were achieved by using a hydrolysis time of 5 h and an enzyme concentration of 2%. Orange seed protein hydrolysate (OSPH) was prepared under these conditions, and peptides were isolated and purified by using size-exclusion chromatography and high-performance liquid chromatography, respectively. The fractions that showed the highest biological activities were analyzed by mass spectrometry in tandem, and a total of 63 peptide sequences were found. Moreover, the effect of simulated gastrointestinal digestion on the bioactivity of the fractions was studied, and the novel peptide sequences generated were also identified. Overall, despite there being some differences in the profile of peptide sequences obtained, the main results showed non-significant differences in the analyzed bioactivities after simulated gastrointestinal digestion.

Biochemical Properties of a Partially Purified Protease from Bacillus sp. CL18 and Its Use to Obtain Bioactive Soy Protein Hydrolysates

Microbial proteases are relevant biocatalysts with diverse applications. Production of protein hydrolysates is recently focused, since they might display biological activities. Therefore, the extracellular protease from Bacillus sp. CL18 was partially purified through ammonium sulfate precipitation (25-50% saturation) and gel filtration chromatography, with a 60.7-fold purification (40,593 U/mg protein) and 21.3% recovery. The partially purified protease (PPP) was characterized as a serine protease, with optimal activity at 51-59 °C and pH 7.4-8.8 and low thermal stability. Thermal inactivation followed first-order kinetics. PPP depended on Ca²⁺ for higher thermal stability, depicted by increases in half-lives (t_1/2), activation energy (E_a), and free energy (ΔG^#) for kinetic inactivation. PPP preferentially hydrolyzed casein > soy protein isolate (SPI) >>> keratinous materials. SPI hydrolysis by PPP was further investigated, and the obtained hydrolysates exhibited increased in vitro bioactivities. Hydrolysates displayed antioxidant capacities through the scavenging of synthetic organic radicals and Fe³⁺-reducing ability. In addition, hydrolysates inhibited the activities of dipeptidyl peptidase IV (DPP IV) and angiotensin-converting enzyme (ACE), suggesting antidiabetic and antihypertensive potentials, respectively. From its biochemical properties, PPP might be used to produce protein hydrolysates with multifunctional bioactivities. Both PPP and SPI hydrolysates can find applications in food biotechnology.

The chemistry behind the antioxidant actions of soy protein isolate hydrolysates in a liposomal system: Their performance in aqueous solutions and liposomes

Soy protein isolate (SPI) and its derived hydrolysates (SPIHs) are popular food ingredients due to their demonstrated antioxidant, stabilizing and emulsifying properties. However, little is known about the interplays among these functions. This study aimed to fill this knowledge gap through comparing the antioxidant activities in single-phase assays systems and biphasic liposomal systems of the SPIHs produced by pepsin, trypsin or alcalase with/without flavourzyme. The peptide fraction of SPIHs with molecular weight < 1 kDa generally contributed more to the detected antioxidant activity. The combination hydrolysis of flavourzyme with pepsin/trypsin/alcalase significantly influenced SPIH's reducing power and Fe2+ chelating capacity. In liposomal systems, SPIHs influenced positively system's stability while inhibiting primary and secondary lipid oxidation products. Besides the factors affecting SPIH's antioxidant activity in the aqueous system (like amino acid composition, sequence and peptide chain length), interactions of peptides/amino acids with liposomal membrane and its lipid components also played critical roles.

Preparation, antioxidant activity evaluation, and identification of antioxidant peptide from black soldier fly (Hermetia illucens L.) larvae

Black soldier fly larvae protein (BLP) was hydrolyzed using alcalase, neutrase, trypsin, and papain. The BLP hydrolysates (BLPHs) were fractionated by ultrafiltration into three peptide fractions of molecular weight (<3 kDa, 3-10 kDa and >10 kDa). Their antioxidant activities in vitro and the amino acid composition were determined. Results showed that the alcalase was more efficient in hydrolyzing the BLP into oligopeptides. BLPHs-I presented the best scavenging activity to superoxide radicals, hydroxyl radicals, DPPH, and ABTS radicals. The best scavenging activities were found in BLPHs-I containing high levels of aromatic and hydrophobic amino acids. Seventeen novel sequences with typical features of well-known antioxidant proteins were identified by LC-MS/MS. Results demonstrated that BLPHs-I possesses a great capacity as antioxidant peptides applied in functional foods. PRACTICAL APPLICATIONS: Black soldier fly larvae protein (BLP) can also be hydrolyzed to produce antioxidant peptides and their sequences were identified. It can be used in pharmaceutical products and functional foods.

Integral Valorization of Pineapple (Ananas comosus L.) By-Products through a Green Chemistry Approach towards Added Value Ingredients

Industrial by-products are produced every day through fruit processing industries. Pineapple is not an exception; when processed, around 60% (w/w) of its weight are peels, stem, trimmings, and crown, the only used fruit part for human consumption. Due to high concerns of sustainability in the food system and negative high impact of human practice in the environment, a strategy has to be developed. Therefore, a green chemistry approach was applied to pineapple by-products to make an integrated valorization by the extraction of bioactive molecules. Two pineapple by-products (peels and stems) were studied, applying a green chemistry approach, which means the non-use of organic solvents or extreme methodologies. A subdivision of each by-product was done by the application of a juice machine. The peels and stems in the fresh state were ground separately, creating two fractions for each by-product—a juice and a wet pulp (press cake). The press cake was characterized, dried, and ground to create a fine powder flour. To the juice, a precipitation methodology with polysaccharides was applied, which allowed the bromelain separation (developing of an enzymatic fraction) from the fruit juice. The enzymatic extract was freeze-dried, and the juice was spray-dried, developing two more fine powders. Thus, three new ingredients were produced from each by-product, creating a total of six new ingredients. Overall, the enzymatic fractions represented around 0.26% (w/w) of pineapple weight. Pineapple stem juice represented 4.8% (w/w), and peel juice represented 17.3% (w/w). Pineapple stem flour represented 3.1% (w/w), and peel flour represented 11.4% (w/w) of the total pineapple weight. To valorize the by-products juices, a full characterization was performed of bioactive molecules and biological activities. When comparing the two juices, the peel juice showed lower content of total phenolic compounds, lower antioxidant capacity, and lower content of vitamin C. The different phenolic compounds were identified by HPLC analysis in the two pineapple by-products juices. However, the same compounds in both juices were quantified (chlorogenic, caffeic, and ferulic acids). On the other hand, the by-products flours had a high content of insoluble dietary fiber (IDF), mainly cellulose and hemicellulose. Therefore, the approach applied in this work opens the door to the production of green products, as a result of by-products valorization. This could be applied not only in the food industry but also in the nutraceutical and cosmetic industries.

Enzymatic hydrolysis of insectAlphitobius diaperinustowards the development of bioactive peptide hydrolysates

Edible insects are a promising protein source for the future generation, due to their nutritional composition, sustainability and low environmental impact.

Antioxidant and Antibacterial Peptides from Soybean Milk through Enzymatic- and Membrane-Based Technologies

Enzymatic hydrolysis of soybean milk proteins with cysteine protease papain was performed in an advanced bioreactor, operated with batch mode. In soybean milk protein hydrolysis reaction, enzyme and substrate ratio and reaction temperature were varied, ranging from 0.029:100–0.457:100 and 30–60 °C, respectively. The degree of hydrolysis of soybean milk proteins was increased with increase of enzyme and substrate (soybean milk protein) ratio. However, the degree of hydrolysis was increased due to change of reaction temperature from 30 °C to 60 °C with enzyme and substrate ratio 0.229:100 and was reduced when hydrolysis reaction was performed with enzyme and substrate ratio 0.11:100 at hydrolysis temperature 60 °C. Antioxidant capacity of enzyme-treated milk had a similar trend with degree of hydrolysis. In a later exercise, a membrane bioreactor was adopted for continuous production of antioxidant and antibacterial peptides from soybean milk. The membrane bioreactor was operated for 12 h with constant feeding. Ceramic-made tubular membrane with a pore size 20 nm was used. Application of static turbulence promoter in a membrane separation process was investigated and its positive effects, with respect to higher permeate flux and lower energy consumption in filtration process, were proven. Antioxidant capacity and antibacterial activity against Bacillus cereus of enzyme-hydrolyzed milk and permeate from membrane were confirmed.

In vitro gastrointestinal digest of catechin-modified β-conglycinin oxidized by lipoxygenase-catalyzed linoleic acid peroxidation

The aim of the present study was to enhance oxidative stability and bioaccessibility of β-conglycinin (7S) prepared from low denatured defatted soybean flours with residual lipids and high lipoxygenase (LOX) activity. The model system consisting of linoleic acid (LA), LOX and unheated 7S (UH-7S)/heated 7S (H-7S) or UH-7S-catechin/H-7S-catechin complex, and in vitro gastrointestinal (GI) digestion model were used to investigate the effect of complexation with catechin on protein oxidation and characterisation of GI digest. The interaction of UH-7S/H-7S with catechin dramatically inhibited LOX-catalyzed LA peroxidation-induced protein oxidation. The interaction also promoted the degree of proteolysis in GI digestion and intestinal absorption for oxidized UH-7S/H-7S, increasing the antioxidant activity of oxidized UH-7S/H-7S, bioaccessibility for catechin and release of di-/tripeptides with dipeptidyl peptidase-IV/angiotensin converting enzyme inhibitory effects or antioxidant activities during GI digestion. The complexation with catechin is a potential strategy to enhance the oxidative stability, GI digestibility and bioaccessibility of 7S.

Enzymatic soy protein hydrolysis: A tool for biofunctional food ingredient production

This work aimed to evaluate the digestive stability of the peptides previously identified from a Corolase PP soy protein hydrolysate (SPH) and to respond to the uncertainty about the merit of controlled hydrolysis. For this purpose, we applied an empirical and theoretical analysis, determining peptide sequences, oxygen radical scavenging (ORAC) and ACE inhibitory (iACE) activities, and the effect of hydrolysis on solubility. Results showed that during digestion most of SPH peptides were degraded as smaller ones. However, both SPH bioactivities improved significantly after digestion (3.9 ± 0.1 μmol TE/mg protein for ORAC and IC50 = 52 ± 4μg protein/mL for iACE) with similar values for soy protein isolate (SPI). With respect to solubility, the controlled hydrolysis considerably increased this functional property. In conclusion, the results indicated that controlled enzymatic hydrolysis of SPI with Corolase PP produced an ingredient more apt to be incorporated in certain nutritional or nutraceutical formulations.

Peptide identification in alcalase hydrolysated pollen and comparison of its bioactivity with royal jelly

Peptides with a similar antioxidant and ACE-inhibitory activity of royal jelly (RJ) generated from Alcalase hydrolysated pollen (AHP) were predicted by Response Surface Methodology (RSM). The model equations were proposed according to the effects of time and enzyme concentration on the antioxidant and ACE-inhibitory activity. The optimum values for Alcalase concentration and hydrolysis time were 1.5% and 4 h, respectively. Later, AHP was prepared and deproteinised to be further analysed using size-exclusion chromatography (SEC). After SEC separation, fractions with the highest activity of ACE-inhibitory, DPPH radical scavenging and ferric-reducing power were purified by RP-HPLC. The highest ACE-inhibitory and DPPH scavenging activity of fractions was found 100% and 66.61%, respectively. The most active fractions were analysed by nano-liquid chromatography and mass spectrometry in tandem (nLC-MS/MS) and a total of 195 peptide sequences were identified. The origins of all peptides were herbal proteins and certain coincidences with previously described bioactive sequences were discussed.

Interactions between soy protein hydrolyzates and wheat proteins in noodle making dough

Soy protein hydrolyzate has been used as supplements in wheat flour to enhance the nutritional value of its products, but it may negatively affect the gluten properties simultaneously. In order to explore the mechanism of this effect, protein characteristics including disulfide bond, protein composition, intermolecular force of dough proteins, and atomic force microscope images of gluten were obtained. Results showed that disulfide bonds in dough increased when soy protein hydrolyzate was added, but glutenin macropolymer decreased. Atomic force microscope images showed that gluten were weakened by soy protein hydrolyzate. Based on these results, a model was developed to describe the interaction between soy protein hydrolyzates and wheat proteins: soy protein hydrolyzates linked with wheat proteins through disulfide bond, disrupted the glutenins polymerization, thus hindered gluten networks formation. The interaction between wheat proteins and soy protein hydrolyzates in noodle making dough could be described with this model reasonably.