Recently isolated food-derived antihypertensive hydrolysates and peptides: A review

Skipjack Tuna (Katsuwonus pelamis) Dark Muscle Hydrolysate Ameliorates Hyperuricemia in Mice via Regulating Gut Microbiota and Serum Metabolism

Peptides have emerged as promising agents for ameliorating hyperuricemia (HUA), a condition that poses significant risks to human health. This study evaluated the HUA-alleviating potential of skipjack tuna dark muscle hydrolysate (STDH) in a mouse model of HUA induced by potassium oxonate (PO) and hypoxanthine (Hx). The results demonstrated elevated serum uric acid (SUA) levels, increased xanthine oxidase (XOD) activity in the serum and liver, and kidney and intestinal damage in HUA mice. Although the standard drug allopurinol (AP) effectively reduced SUA levels and lowered XOD activity in the serum and liver, it exacerbated kidney damage and caused significant weight loss. In contrast, STDH intervention not only significantly lowered SUA, serum creatinine (SCr), and blood urea nitrogen (BUN) levels but also inhibited XOD activity in serum and liver. Notably, STDH ameliorated renal and intestinal morphological damage, as evidenced by hematoxylin-eosin (HE) staining. Gut microbiome analysis further revealed that STDH normalized the HUA-associated elevation of the Bacteroidetes/Firmicutes ratio. Untargeted metabolomics identified STDH's regulatory effects on glycine, serine, and threonine metabolism; arginine and proline metabolism; and glycerophospholipid metabolism, with glutamine implicated as a key player in HUA pathogenesis. These findings demonstrate that STDH effectively alleviates HUA while avoiding adverse effects associated with conventional therapy, positioning it as a safe and cost-effective functional food candidate for HUA management.

Clam peptides: Preparation, flavor properties, health benefits, and safety risks

Bioactive peptides derived from food proteins have attracted attention for their potential roles in functional foods and pharmaceuticals. Clams, renowned for their protein content and essential amino acids critical to human health, represent a promising source for bioactive peptide production. Recent studies have extensively explored the preparation methods, flavor profiles, and health benefits of clam peptides (CPs). However, there is still a lack of a comprehensive review on the current status of CPs development. This review revealed that enzymatic hydrolysis is the predominant methods for CPs production, which is a potential resource for discovering umami peptides. CPs exhibit diverse bioactivities, including antioxidative, antibacterial, ACE inhibitory, immunomodulatory, and anticancer activities. However, the potential presence of heavy metals, pathogenic bacteria, and allergens in raw materials underscores the need for stringent safety evaluations. In the future, production technology, in vivo fate, health efficacy mechanisms and safety will be interesting directions for CPs research.

Effect of fish meal substitution with trout viscera protein hydrolysate on the innate immune response of red tilapia (Oreochromis spp)

This study evaluated the effect of replacing fish meal (FM) with concentrated trout viscera protein hydrolysate (TVPH) on the immune response in juvenile red tilapia (Oreocheromis spp). Five isoenergetic and isoproteic experimental diets were prepared by substituting FM with TVPH at different substitution ratios: 0% (control, D1) 25% (D2), 50% (D3), 75% (D4), and 100% (D5). A total of 180 red tilapia were distributed in 15 tanks. Fish from three tanks were fed daily at 2% of the biomass for 25 days with one of the five diets mentioned above. At the end of the trial, the fish were counted, weighed, measured, and skin mucus and serum samples were obtained to study different parameters related to humoral immunity. The results indicate a 100% survival rate in all fish groups and did not show significant differences in terms of growth and feed efficiency. On the other hand, the fish fed diets D2 and D3 had significantly higher serum protein values. Also, fish fed the D2 or D5 diets had higher lysozyme activity and fish fed the D2 diet also had significantly higher total immunoglobulin levels than fish fed the control diet. In mucus, fish fed the D2 or D4 diets showed significantly higher mucus protein levels than control fish. However, anti-protease and bactericidal activity decreased in fish fed the D5 or D4 diets, respectively. These results demonstrate that the D2 and D3 diets positively modulate the immune response of juvenile red tilapia compared to that of fish fed the control diet.

Identification and characterization of umami-ACE inhibitory peptides from traditional fermented soybean curds

Fermented soybean curds (FSC) are popular because of its umami taste. Its bioactivities are of interest. Peptides in FSC were identified using nano-HPLC-MS/MS, and 11 candidate peptides showing potential umami and ACE inhibitory activities were screened using various databases. Pharmacophore model analysis showed their high probability of ACE inhibition with fit values >2, which showed the peptides bound to umami receptors and ACE mainly through hydrogen bond, and electrostatic and hydrophobic interactions. Additionally, their docking and interaction energy were independent of the peptide length. Three high umami-ACE inhibitory peptides (VE, FEF, and WEEF) were synthesized. Their umami thresholds were WEEF (0.32 mM) < FEF (0.55 mM) < VE (1.10 mM), while their IC50 were WEEF (85 ± 2 μM) < FEF (170 ± 10 μM) < VE (205 ± 5 μM). NO and ET-1 production were dose-dependent with WEEF showing the best ACE inhibitory activity. The results allowed identification of effective umami agents and ACE inhibitory peptides from fermented soybean products. It could also be useful method for screening potential umami-ACE inhibitory peptides.

Angiotensin converting enzyme inhibitory hydrolysate and peptide fractions from chicken skin collagen, as modulators of lipid accumulation in adipocytes 3 T3-L1, after in vitro gastrointestinal digestion

Inhibitory activity against angiotensin-converting enzyme (IAACE) by chicken skin collagen hydrolysate (CSCH) and their peptide fractions before and after in-vitro gastrointestinal digestion, were evaluated; as well as their ability to modulate lipid accumulation in 3 T3-L1 adipocytes. Before digestion, peptide fraction <1 kDa (F4) showed the highest IAACE (p < 0.05) followed by CSCH. After these samples were digested, F4 presented an IAACE with IC50 similar to its digest (DF4) (188.84 and 220.03 μg/mL, respectively), which was 2-fold lower (p < 0.05) than IC50 of fraction <1 kDa from post-digested hydrolysate (FDH) (388.57 μg/mL). Nine peptides were identified as the potential ACE inhibitors in F4 and DF4. Addition of DF4 (800 μg/mL) reduced(p < 0.05) lipid accumulation by 83% within preadipocytes. A 45-60% reduction of lipid accumulation within differentiated adipocytes was obtained by adding FDH and DF4 (regardless the concentration). These results, digested CSCH and F4 with IAACE may be considered as potential adjuvants for obesity treatment.

Molecular insights into the inhibition of angiotensin-converting enzyme 1 by hemopressin peptides

Inhibiting angiotensin-converting enzyme 1 (ACE1) is a key strategy for managing hypertension as it prevents the formation of angiotensin II, a potent vasoconstrictor. Given the adverse effects associated with synthetic inhibitors, there is an increasing focus on exploring natural bioactive peptides as potential ACE1 inhibitors. Hemopressins (Hp) are peptides derived from hemoglobin. The present study investigated the ACE1 inhibitory activity of two Hp variants, Hp bearing phenylalaine (Hp-F) and Hp bearing leucine (Hp-L), using a combination of in vitro and in silico methodologies. In enzyme inhibition assays, Hp-L variants exhibited better inhibition when compared to Hp-F variants. Furthermore, in molecular docking and molecular dynamics simulations, Hp-L variants displayed favorable binding characteristics, in terms of binding energy and interactions, supporting their potential to be effective ACE1 inhibitors. The peptides were observed to interact with key residues involved in binding widely used ACE1 inhibitors. Notably, peptide RVD-Hp-L (RVDPVNFKLLSH) showed the lowest IC50 value, higher binding affinity and sustained interactions while binding to the catalytic site of ACE1. Finally, the substitution of phenylalanine with leucine in hemopressins significantly enhances their binding affinity and inhibitory potency.

AI4ACEIP: A Computing Tool to Identify Food Peptides with High Inhibitory Activity for ACE by Merged Molecular Representation and Rich Intrinsic Sequence Information Based on an Ensemble Learning Strategy

Hypertension is a common chronic disorder and a major risk factor for cardiovascular diseases. Angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II, causing vasoconstriction and raising blood pressure. Pharmacotherapy is the mainstay of traditional hypertension treatment, leading to various negative side effects. Some food-derived peptides can suppress ACE, named ACEIP with fewer undesirable effects. Therefore, it is crucial to seek strong dietary ACEIP to aid in hypertension treatment. In this article, we propose a new model called AI4ACEIP to identify ACEIP. AI4ACEIP uses a novel two-layer stacked ensemble architecture to predict ACEIP relying on integrated view features derived from sequence, large language models, and molecular-based information. The analysis of feature combinations reveals that four selected integrated feature pairs exhibit enhancing performance for identifying ACEIP. For finding meta models with strong abilities to learn information from integrated feature pairs, PowerShap, a feature selection method, is used to select 40 optimal feature and meta model combinations. Compared with seven state-of-the-art methods on the source and clear benchmark data sets, AI4ACEIP significantly outperformed by 8.47 to 20.65% and 5.49 to 14.42% for Matthew's correlation coefficient. In brief, AI4ACEIP is a reliable model for ACEIP prediction and is freely available at https://github.com/abcair/AI4ACEIP.

Sequence-Activity Relationship of Angiotensin-Converting Enzyme Inhibitory Peptides Derived from Food Proteins, Based on a New Deep Learning Model

Food-derived peptides are usually safe natural drug candidates that can potentially inhibit the angiotensin-converting enzyme (ACE). The wet experiments used to identify ACE inhibitory peptides (ACEiPs) are time-consuming and costly, making it important and urgent to reduce the scope of experimental validation through bioinformatics methods. Here, we construct an ACE inhibitory peptide predictor (ACEiPP) using optimized amino acid descriptors (AADs) and long- and short-term memory neural networks. Our results show that combined-AAD models exhibit more efficient feature transformation ability than single-AAD models, especially the training model with the optimal descriptors as the feature inputs, which exhibits the highest predictive ability in the independent test (Acc = 0.9479 and AUC = 0.9876), with a significant performance improvement compared to the existing three predictors. The model can effectively characterize the structure-activity relationship of ACEiPs. By combining the model with database mining, we used ACEiPP to screen four ACEiPs with multiple reported functions. We also used ACEiPP to predict peptides from 21,249 food-derived proteins in the Database of Food-derived Bioactive Peptides (DFBP) and construct a library of potential ACEiPs to facilitate the discovery of new anti-ACE peptides.

From Sea to Lab: Angiotensin I-Converting Enzyme Inhibition by Marine Peptides-Mechanisms and Applications

To reveal potent ACE inhibitors, researchers screen various bioactive peptides from several sources, and more attention has been given to aquatic sources. This review summarizes the recent research achievements on marine peptides with ACE-inhibitory action and application. Marine peptides are considered excellent bioactives due to their large structural diversity and unusual bioactivities. The mechanisms by which these marine peptides inhibit ACE include competitive binding to ACEs' active site, interfering with ACE conformational changes, and avoiding the identification of substrates. The unique 3D attributes of marine peptides confer inhibition advantages toward ACE activity. Because IC50 values of marine peptides' interaction with ACE are low, structure-based research assumes that the interaction between ACE and peptides increased the therapeutic application. Numerous studies on marine peptides focused on the sustainable extraction of ACE-inhibitory peptides produced from several fish, mollusks, algae, and sponges. Meanwhile, their potential applications and medical benefits are worth investigating and considering. Due to these peptides exhibiting antioxidant, antihypertensive, and even antimicrobial properties simultaneously, their therapeutic potential for cardiovascular disease and other illnesses only increases. In addition, as marine peptides show better pharmacological benefits, they have increased absorption rates and low toxicity and could perhaps be modified for better stability and bioefficacy. Biotechnological advances in peptide synthesis and formulation have greatly facilitated the generation of peptide-based ACE inhibitors from marine sources, which subsequently offer new treatment models. This article gives a complete assessment of the present state of knowledge about marine organism peptides as ACE inhibitors. In addition, it emphasizes the relevance of additional investigation into their mechanisms of action, the optimization of manufacturing processes, and assessment in in vivo, preclinical, and clinical settings, underlining the urgency and value of this study. Using marine peptides for ACE inhibition not only broadens the repertory of bioactive compounds but also shows promise for tackling the global health burden caused by cardiovascular diseases.

Recent progress in the preparation of bioactive peptides using simulated gastrointestinal digestion processes

Bioactive peptides (BAPs) represent a unique class of peptides known for their extensive physiological functions and their role in enhancing human health. In recent decades, owing to their notable biological attributes such as antioxidant, antihypertensive, antidiabetic, and anti-inflammatory activities, BAPs have received considerable attention. Simulated gastrointestinal digestion (SGD) is a technique designed to mimic physiological conditions by adjusting factors such as digestive enzymes and their concentrations, pH levels, digestion duration, and salt content. Initially established for analyzing the gastrointestinal processing of foods or their constituents, SGD has recently become a preferred method for generating BAPs. The BAPs produced via SGD often exhibit superior biological activity and stability compared with those of BAPs prepared via other methods. This review offers a comprehensive examination of the recent advancements in BAP production from foods via SGD, addressing the challenges of the method and outlining prospective directions for further investigation.

Bioactive Peptides from Corn (Zea mays L.) with the Potential to Decrease the Risk of Developing Non-Communicable Chronic Diseases: In Silico Evaluation

Studies have shown that corn (Zea mays L.) proteins, mainly α-zein, have the potential to act on therapeutic targets related to non-communicable chronic diseases, such as high blood pressure and type 2 diabetes. Enzymatic hydrolysis of proteins present in foods can result in a great diversity of peptides with different structures and possible bioactivities. A review of recent scientific research papers was performed to show evidence of the bioactive properties of corn peptides by in vitro assays. The α-zein amino acid sequences were identified in the UniProtKB protein database and then analyzed in the BIOPEP database to simulate enzymatic digestion and verify the potential biological action of the resulting peptides. The peptides found in the BIOPEP database were categorized according to the probability of presenting biological action using the PeptideRanker database. The aim was to use existing data to identify in silico the potential for obtaining biologically active peptides from α-zein, the main storage protein of corn. The analysis showed that the majority of peptide fragments were related to the inhibition of angiotensin-converting enzyme, followed by the inhibition of dipeptidyl peptidase IV and dipeptidyl peptidase III. Many drugs used to treat high blood pressure and type 2 diabetes work by inhibiting these enzymes, suggesting that corn peptides could be potential alternative agents. In vitro studies found that the primary bioactivity observed was antioxidative action. Both in vitro and in silico approaches are valuable for evaluating the bioactive properties resulting from protein hydrolysis, such as those found in α-zein. However, conducting in vitro studies based on prior in silico evaluation can be more efficient and cost-effective.

Gastrointestinal digestion of food proteins: Anticancer, antihypertensive, anti-obesity, and immunomodulatory mechanisms of the derived peptides

Food proteins and their peptides play a significant role in the important biological processes and physiological functions of the body. The peptides show diverse biological benefits ranging from anticancer to antihypertensive, anti-obesity, and immunomodulatory, among others. In this review, an overview of food protein digestion in the gastrointestinal tract and the mechanisms involved was presented. As some proteins remain resistant and undigested, the multifarious factors (e.g. protein type and structure, microbial composition, pH levels and redox potential, host factors, etc.) affecting their colonic fermentation, the derived peptides, and amino acids that evade intestinal digestion are thus considered. The section that follows focuses on the mechanisms of the peptides with anticancer, antihypertensive, anti-obesity, and immunomodulatory effects. As further considerations were made, it is concluded that clinical studies targeting a clear understanding of the gastrointestinal stability, bioavailability, and safety of food-based peptides are still warranted.

The novel angiotensin-I-converting enzyme inhibitory peptides from Scomber japonicus muscle protein hydrolysates: QSAR-based screening, molecular docking, kinetic and stability studies

Food-derived angiotensin-converting enzyme-inhibitory (ACE-I) peptides have attracted extensive attention. Herein, the ACE-I peptides from Scomber japonicus muscle hydrolysates were screened, and their mechanisms of action and inhibition stability were explored. The quantitative structure-activity relationship (QSAR) model based on 5z-scale metrics was developed to rapidly screen for ACE-I peptides. Two novel potential ACE-I peptides (LTPFT, PLITT) were predicted through this model coupled with in silico screening, of which PLITT had the highest activity (IC50: 48.73 ± 7.59 μM). PLITT inhibited ACE activity with a mixture of non-competitive and competitive mechanisms, and this inhibition mainly contributed to the hydrogen bonding based on molecular docking study. PLITT is stable under high temperatures, pH, glucose, and NaCl. The zinc ions (Zn2+) and copper ions (Cu2+) enhanced ACE-I activity. The study suggests that the QSAR model is effective in rapidly screening for ACE-I inhibitors, and PLITT can be supplemented in foods to lower blood pressure.

PeposX-Exhaust: A lightweight and efficient tool for identification of short peptides

Short peptides have become the focus of recent research due to their variable bioactivities, good digestibility and wide existences in food-derived protein hydrolysates. However, due to the high complexity of the samples, identifying short peptides still remains a challenge. In this work, a tool, named PeposX-Exhaust, was developed for short peptide identification. Through validation with known peptides, PeposX-Exhaust identified all the submitted spectra and the accuracy rate reached 75.36%, and the adjusted accuracy rate further reached 98.55% when with top 5 candidates considered. Compared with other tools, the accuracy rate by PeposX-Exhaust was at least 70% higher than two database-search tools and 15% higher than the other two de novo-sequencing tools, respectively. For further application, the numbers of short peptides identified from soybean, walnut, collagen and bonito protein hydrolysates reached 1145, 628, 746 and 681, respectively. This fully demonstrated the superiority of the tool in short peptide identification.

Two novel angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibiting peptides from tilapia (Oreochromis mossambicus) skin and their molecular docking mechanism

In the study, papain was used to hydrolyze tilapia (Oreochromis mossambicus) skin to obtain a tilapia skin hydrolysate (TSH) with dual angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibitory activities. The resulting TSH was sequentially fractionated by ultrafiltration, size exclusion separation chromatography, and reverse-phase high-performance liquid chromatography. Its inhibitory effects on ACE and DPP-IV were determined by commercial reagent kits. Two peptides purified from TSH were identified as Gly-Pro-Leu-Gly-Ala-Leu (GPLGAL) and Lys-Pro-Ala-Gly-Asn (KPAGN) by the ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Inhibitory concentration (IC50) of GPLGAL on ACE and DPP-IV were 117.20 ± 1.69 and 187.10 ± 2.75 µM, respectively. IC50 of KPAGN on ACE and DPP-IV were 137.40 ± 2.33 and 259.20 ± 2.85 µM, respectively. The molecular simulation demonstrated that the binding affinities of GPLGAL to ACE and DPP-IV proteins were -8.5 and -7.4 kcal/mol, respectively, whereas those of KPAGN to ACE and DPP-IV proteins were -7.9 and -6.7 kcal/mol, respectively. GPLGAL interacted with 21 amino acid residues of the ACE active site, whereas KPAGN engaged with 19 amino acid residues. Additionally, GPLGAL interacted with 10 amino acid residues of the DPP-IV active site, whereas KPAGN engaged with 13 amino acid residues. The two peptides predominantly occupied the active sites of ACE (His513, Tyr523, and Ala354) and DPP-IV (Tyr662 and Arg125) through hydrogen bonding. This leads to the deactivation of ACE and DPP-IV. PRACTICAL APPLICATION: Accelerate tilapia skin development and high-value utilization; provide foundation for preparing the peptides with dual ACE and DPP-IV inhibiting activity.

Developing Lipase Inhibitor as a Novel Approach to Address the Rice Bran Rancidity Issue─A Critical Review

Rice bran is a valuable byproduct from the food processing industry, which contains abundant protein, essential unsaturated fatty acids, and numerous bioactive compounds. However, its susceptibility to rancidity greatly restricts its wide utilization. Many strategies have been proposed to delay the rancidity of rice bran, but most of them have their respective limitations. Here, we proposed that developing rice ban lipase peptide inhibitors represents an alternative and promising prescription for impeding the rancidity of rice bran, in contrast to the conventional stabilization approaches for rice bran. For this reason, the rancidity mechanisms of rice bran and the research progress of rice bran lipases were discussed. In addition, the feasibility of utilizing in silico screening and phage display, two state-of-the-art technologies, in the design of the related peptide inhibitors was also highlighted. This knowledge is expected to provide a theoretical basis for opening a new avenue for stabilizing rice bran.

In vitro, ex vivo and in vivo antihypertensive evaluation of enzymatic hydrolysates of Californian red worm (Eisenia fetida) proteins

Hypertension is an important risk factor concomitant with cardiovascular disease (CVD) states, which is why we set out to evaluate Californian red worm hydrolysates on antihypertensive activity both in vitro, ex vivo, using rabbit aortic rings and in vivo using hypertensive induced rats. The worms were manually separated, washed with water, purged for 4 h with 4 % sodium bicarbonate, sacrificed with 7 % saline, and finally washed with drinking water. The in vitro antihypertensive capacity was performed by measuring angiotensin-converting enzyme inhibition; for the ex vivo assays, rabbit aorta was used to measure relaxation; for the in vivo assays, rats with induced hypertension were used to perform acute (hypotension) and chronic assays, using captopril as a control in all assays. With respect to angiotensin-converting enzyme (ACE) inhibition, the EC50 value of the worm hydrolysate was found to be 358 ppm; with respect to the analysis in aortic rings, it was found that the mechanisms of action of the hydrolysate are endothelium-dependent, presenting a maximum relaxation of 35 %. With respect to the in vivo assays, the hypotensive test showed that the hydrolysate can reduce blood pressure by up to 32 % in only 2 h, while the chronic analysis showed that the hydrolysate at 150 ppm did not present statistically significant differences with the control (captopril) during the 15 days of analysis. The Red Californian earthworm hydrolysate presents bioactive compounds identified with antihypertensive activities in vitro, ex vivo and in vivo in different isolated and animal models. The study demonstrates the efficacy of the hydrolysate to be used as an alternative in the treatment and prevention of hypertension, and it can be implemented in functional foods or nutraceutical foods. Antihypertensive peptides, particularly those that inhibit angiotensin-converting enzyme (ACE), hold significant importance in medical research, specifically in the context of cardiovascular disease treatment, particularly hypertension. The focus on these peptides and the potential implications of their results in medical research can be summarized through several key points: 1) Mechanisms of Action-Antihypertensive peptides function by inhibiting ACE or renin, crucial enzymes in blood pressure regulation. 2)Alternatives to Synthetic Drugs, 3) Additional Health Benefits, and various other factors.

Plant-derived rennet: research progress, novel strategies for their isolation, identification, mechanism, bioactive peptide generation, and application in cheese manufacturing

Rennet, an aspartate protease found in the stomach of unweaned calves, effectively cuts the peptide bond between Phe105-Met106 in κ-casein, hydrolyzing the casein micelles to coagulate the milk and is a crucial additive in cheese production. Rennet is one of the most used enzymes of animal origin in cheese making. However, using rennet al.one is insufficient to meet the increasing demand for cheese production worldwide. Numerous studies have shown that plant rennet can be an alternative to bovine rennet and exhibit a good renneting effect. Therefore, it is crucial and urgent to find a reliable plant rennet. Based on our team's research on rennet enzymes of plant origin, such as from Dregea sinensis Hemsl. and Moringa oleifer Lam., for more than ten years, this paper reviews the relevant literature on rennet sources, isolation, identification, rennet mechanism, functional active peptide screening, and application in cheese production. In addition, it proposes the various techniques for targeted isolation and identification of rennet and efficient screening of functionally active peptides, which show excellent prospects for development.

Antioxidant and Renin Inhibitory Activities of Peptides from Food Proteins on Hypertension: A Review

Hypertension is a condition induced by oxidative stress causing an alteration in the endothelium, which increases the risk of suffering from other degenerative diseases. This review compiles the findings on peptides from food proteins with antioxidant and antihypertensive activities. Antihypertensive peptides are mainly focused on renin inhibition. Peptides containing hydrophobic amino acids have antioxidant and renin inhibitory activities, as reported by studies on the biological activity of peptides from various food sources evaluated separately and simultaneously. Peptides from food sources can present multiple biological activities. Moreover, antioxidant peptides have the potential to be evaluated against renin, offering an alternative for hypertension therapy without causing adverse side effects.

Red Quinoa Hydrolysates with Antioxidant Properties Improve Cardiovascular Health in Spontaneously Hypertensive Rats

In recent years, quinoa has been postulated as an emerging crop for the production of functional foods. Quinoa has been used to obtain plant protein hydrolysates with in vitro biological activity. The aim of the present study was to evaluate the beneficial effect of red quinoa hydrolysate (QrH) on oxidative stress and cardiovascular health in an in vivo experimental model of hypertension (HTN) in the spontaneously hypertensive rat (SHR). The oral administration of QrH at 1000 mg/kg/day (QrHH) showed a significant reduction in SBP from baseline (-9.8 ± 4.5 mm Hg; p < 0.05) in SHR. The mechanical stimulation thresholds did not change during the study QrH groups, whereas in the case of SHR control and SHR vitamin C, a significant reduction was observed (p < 0.05). The SHR QrHH exhibited higher antioxidant capacity in the kidney than the other experimental groups (p < 0.05). The SHR QrHH group showed an increase in reduced glutathione levels in the liver compared to the SHR control group (p < 0.05). In relation to lipid peroxidation, SHR QrHH exhibited a significant decrease in plasma, kidney and heart malondialdehyde (MDA) values compared to the SHR control group (p < 0.05). The results obtained revealed the in vivo antioxidant effect of QrH and its ability to ameliorate HTN and its associated complications.

Bioactive Antimicrobial Peptides from Food Proteins: Perspectives and Challenges for Controlling Foodborne Pathogens

Bioactive peptides (BAPs) derived from food proteins have been extensively studied for their health benefits, majorly exploring their potential use as nutraceuticals and functional food components. These peptides possess a range of beneficial properties, including antihypertensive, antioxidant, immunomodulatory, and antibacterial activities, and are naturally present within dietary protein sequences. To release food-grade antimicrobial peptides (AMPs), enzymatic protein hydrolysis or microbial fermentation, such as with lactic acid bacteria (LAB), can be employed. The activity of AMPs is influenced by various structural characteristics, including the amino acid composition, three-dimensional conformation, liquid charge, putative domains, and resulting hydrophobicity. This review discusses the synthesis of BAPs and AMPs, their potential for controlling foodborne pathogens, their mechanisms of action, and the challenges and prospects faced by the food industry. BAPs can regulate gut microbiota by promoting the growth of beneficial bacteria or by directly inhibiting pathogenic microorganisms. LAB-promoted hydrolysis of dietary proteins occurs naturally in both the matrix and the gastrointestinal tract. However, several obstacles must be overcome before BAPs can replace antimicrobials in food production. These include the high manufacturing costs of current technologies, limited in vivo and matrix data, and the difficulties associated with standardization and commercial-scale production.

Recent advances of bioactive proteins/polypeptides in the treatment of breast cancer

Proteins do not only serve as nutrients to fulfill the demand for food, but also are used as a source of bioactive proteins/polypeptides for regulating physical functions and promoting physical health. Female breast cancer has the highest incidence in the world and is a serious threat to women's health. Bioactive proteins/polypeptides exert strong anti-tumor effects and exhibit inhibition of multiple breast cancer cells. This review discussed the suppressing effects of bioactive proteins/polypeptides on breast cancer in vitro and in vivo, and their mechanisms of migration and invasion inhibition, apoptosis induction, and cell cycle arrest. This may contribute to providing a basis for the development of bioactive proteins/polypeptides for the treatment of breast cancer.

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Selected Seeds as Sources of Bioactive Compounds with Diverse Biological Activities

Seeds contain a variety of phytochemicals that exhibit a wide range of biological activities. Plant-derived compounds are often investigated for their antioxidant, anti-inflammatory, immunomodulatory, hypoglycemic, anti-hypercholesterolemic, anti-hypertensive, anti-platelet, anti-apoptotic, anti-nociceptive, antibacterial, antiviral, anticancer, hepatoprotective, or neuroprotective properties. In this review, we have described the chemical content and biological activity of seeds from eight selected plant species-blackberry (Rubus fruticosus L.), black raspberry (Rubus coreanus Miq.), grape (Vitis vinifera L.), Moringa oleifera Lam., sea buckthorn (Hippophae rhamnoides L.), Gac (Momordica cochinchinensis Sprenger), hemp (Cannabis sativa L.), and sacha inchi (Plukenetia volubilis L). This review is based on studies identified in electronic databases, including PubMed, ScienceDirect, and SCOPUS. Numerous preclinical, and some clinical studies have found that extracts, fractions, oil, flour, proteins, polysaccharides, or purified chemical compounds isolated from the seeds of these plants display promising, health-promoting effects, and could be utilized in drug development, or to make nutraceuticals and functional foods. Despite that, many of these properties have been studied only in vitro, and it's unsure if their effects would be relevant in vivo as well, so there is a need for more animal studies and clinical trials that would help determine if they could be applied in disease prevention or treatment.

Screening and Molecular Mechanisms of Novel ACE-Inhibitory Peptides from Gracilariopsis lemaneiformis

Candidate peptides with novel angiotensin-I-converting enzyme (ACE) inhibitor activity were obtained from hydrolysates of Gracilariopsis lemaneiformis by virtual screening method. Our results showed that G. lemaneiformis peptides (GLP) could significantly lower blood pressure in spontaneously hypertensive rats (SHR). At least 101 peptide sequences of GLP were identified by LC-MS/MS analysis and subjected to virtual screening. A total of 20 peptides with the highest docking score were selected and chemically synthesized in order to verify their ACE-inhibitory activities. Among them, SFYYGK, RLVPVPY, and YIGNNPAKG showed good effects with IC₅₀ values of 6.45 ± 0.22, 9.18 ± 0.42, and 11.23 ± 0.23 µmoL/L, respectively. Molecular docking studies revealed that three peptides interacted with the active center of ACE by hydrogen bonding, hydrophobic interactions, and electrostatic forces. These peptides could form stable complexes with ACE. Furthermore, SFYYGK, RLVPVPY, and YIGNNPAKG significantly reduced systolic blood pressure (SBP) in SHR. YIGNNPAKG exhibited the highest antihypertensive effect, with the largest decrease in SBP (approximately 23 mmHg). In conclusion, SFYYGK, RLVPVPY, and YIGNNPAKG can function as potent therapeutic candidates for hypertension treatment.

Potential antihypertensive mechanism of egg white-derived peptide QIGLF revealed by proteomic analysis

Previous work has shown that egg white-derived peptide QIGLF has significant in vivo antihypertensive activity. This study aimed to clarify the antihypertensive mechanisms of QIGLF on spontaneously hypertensive rats (SHRs) by a serum proteomic approach. Here, the tandem mass tag (TMT) quantitative proteomic was performed to discover serum protein changes in SHRs with QIGLF. As a result, SHRs with 4 weeks of QIGLF treatment have distinct serum protein expression profiles by principal component and Pearson's correlation coefficient analysis. Based on Gene Ontology (GO) annotation, oxygen transport and organelle fusion were found to be a regulated major biological process. Besides, aldosterone regulated sodium reabsorption, mitophagy, gap junction, and tight junction were significantly regulated based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. QIGLF might exert antihypertensive effects in the SHRs by inhibiting Na+ reabsorption and oxidative stress, restoring gap junction and tight junction.

Plant derived antimicrobial peptides: Mechanism of target, isolation techniques, sources and pharmaceutical applications

Antimicrobial resistance is a global health and development threat which is caused by the excess and prolonged usage of antimicrobial compounds in agriculture and pharmaceutical industries. Resistance of pathogenic microorganisms to the already existing drugs represent a serious risk to public health. Plant sources such as cereals, legumes, fruits and vegetables are potential substrates for the isolation of antimicrobial peptides (AMP) with broad spectrum antimicrobial activity against bacteria, fungi and viruses with novel immunomodulatory activities. Thus, in the quest of new antimicrobial agents, AMPs have recently gained interest. Therefore, AMP can be used in agriculture, pharmaceutical and food industries. This review focuses on various explored and unexplored plant based food sources of AMPs, their isolation techniques and antimicrobial mechanism of peptides. Therefore, the literature discussed in this review paper will prove beneficial the research purposes for agriculture, pharmaceutical and food industries. PRACTICAL APPLICATIONS: Isolation of antimicrobial peptides (AMPs) can be done on industrial scale. AMP isolated from food sources can be used in pharmaceutical and agriculture industries. AMP from natural sources mitigate the problem of antimicrobial resistance. AMP isolated from food products can be used as nutraceutical.

Preparation, Characterization and In Vitro Stability of a Novel ACE-Inhibitory Peptide from Soybean Protein

A soy protein isolate was hydrolyzed with Alcalase®, Flavourzyme® and their combination, and the resulting hydrolysates (A, F and A + F) were ultrafiltered and analyzed through SDS-PAGE. Fractions with MW < 1 kDa were investigated for their ACE-inhibitory activity, and the most active one (A < 1 kDa) was purified by semi-preparative RP-HPLC, affording three further subfractions. NMR analysis and Edman degradation of the most active subfraction (A1) enabled the identification of four putative sequences (ALKPDNR, VVPD, NDRP and NDTP), which were prepared by solid-phase synthesis. The comparison of their ACE-inhibitory activities suggested that the novel peptide NDRP might be the main agent responsible for A1 fraction ACE inhibition (ACE inhibition = 87.75 ± 0.61%; IC50 = 148.28 ± 9.83 μg mL−1). NDRP acts as a non-competitive inhibitor and is stable towards gastrointestinal simulated digestion. The Multiple Reaction Monitoring (MRM) analysis confirmed the presence of NDRP in A < 1 kDa.

Recent findings on the cellular and molecular mechanisms of action of novel food-derived antihypertensive peptides

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Hypertension has remained a silent-killer.

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Novel peptides recently isolated from food proteins.

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Molecular mechanism of blood pressure-lowering: renin and ACE-inhibition, and beyond.

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Proposed molecular mechanisms for future research.

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Novel peptides are excellent candidates for nutraceutical development.

Hypertension impacts negatively on the quality of life of sufferers, and complications associated with uncontrolled hypertension are life-threatening. Hence, many research efforts are exploring the antihypertensive properties of bioactive peptides derived from food proteins using in vitro ACE-inhibitory assay, experimentally-induced and spontaneous hypertensive rats, normotensive and hypertensive human models. In this study, the cellular and molecular mechanisms of blood pressure-lowering properties of novel peptides reported in recent studies (2015-July 30, 2021) were discussed. In addition to common mechanisms such as the inhibition of angiotensin I-converting enzyme (ACE) and renin activities, recently recognized mechanisms through which bioactive peptides exert their antihypertensive properties including the induction of vasodilation via upregulation of cyclo-oxygenase (COX) and prostaglandin receptor and endothelial nitric oxide synthase expression and L-type Ca²⁺ channel blockade were presented. Similarly, emerging mechanisms of blood pressure-lowering by bioactive peptides such as modulation of inflammation (TNF-α, and other cytokines signaling), oxidative stress (Keap-1/Nrf2/ARE/HO-1 and related signaling pathways), PPAR-γ/caspase3/MAPK signaling pathways and inhibition of lipid accumulation were discussed. The review also highlighted factors that influence the antihypertensive properties of peptides such as method of hydrolysis (type and number of enzymes, and chemical used for hydrolysis, and microbial fermentation), and amino acid sequence and chain length of peptides.

Recent advances in bioactive peptides from cereal-derived Foodstuffs

Cereal-derived proteins account for a major part of human dietary protein consumption. Natural bioactive peptides (NBPs) from these proteins involve a variety of physiological activities and play an important role in the promotion of human health. This review focuses on the characteristics of NBPs obtained from cereals, and the commonly used methods for preparation, separation, purification, and identification. We also discussed the biological functions of cereal-derived NBPs (CNBPs), including the activities of antioxidant, immunomodulatory, antimicrobial, and regulation of hyperglycaemia and hypertension. The paper summarised the latest progress in the research and application of CNBPs and analysed the prospects for the development and application of several protein by-products, providing an important way to improve the added value of protein by-products in cereal processing.

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.

Novel angiotensin-converting enzyme inhibitory peptides from tuna byproducts—milts: Preparation, characterization, molecular docking study, and antioxidant function on H2O2-damaged human umbilical vein endothelial cells

To prepare peptides with high angiotensin-converting enzyme (ACE) inhibitory (ACEi) activity, Alcalase was screened from five proteases and employed to prepare protein hydrolysate (TMH) of skipjack tuna (Katsuwonus pelamis) milts. Subsequently, 10 novel ACEi peptides were isolated from the high-ACEi activity TMH and identified as Tyr-Asp-Asp (YDD), Thr-Arg-Glu (TRE), Arg-Asp-Tyr (RDY), Thr-Glu-Arg-Met (TERM), Asp-Arg-Arg-Tyr-Gly (DRRYG), Ile-Cys-Tyr (ICY), Leu-Ser-Phe-Arg (LSFR), Gly-Val-Arg-Phe (GVRF), Lys-Leu-Tyr-Ala-Leu-Phe (KLYALF), and Ile-Tyr-Ser-Pro (IYSP) with molecular weights of 411.35, 404.41, 452.45, 535.60, 665.69, 397.48, 521.61, 477.55, 753.91, and 478.53 Da, respectively. Among them, the IC₅₀ values of ICY, LSFR, and IYSP on ACE were 0.48, 0.59, and 0.76 mg/mL, respectively. The significant ACEi activity of ICY, LSFR, and IYSP with affinities of −7.0, −8.5, and −8.3 kcal/mol mainly attributed to effectively combining with the ACEi active sites through hydrogen bonding, electrostatic force, and hydrophobic interaction. Moreover, ICY, LSFR, and IYSP could positively influence the production of nitric oxide (NO) and endothelin-1 (ET-1) secretion in human umbilical vein endothelial cells (HUVECs) and weaken the adverse impact of norepinephrine (NE) on the production of NO and ET-1. In addition, ICY, LSFR, and IYSP could provide significant protection to HUVECs against H₂O₂ damage by increasing antioxidase levels to decrease the contents of reactive oxide species and malondialdehyde. Therefore, the ACEi peptides of ICY, LSFR, and IYSP are beneficial functional molecules for healthy foods against hypertension and cardiovascular diseases.

Underlying antihypertensive mechanism of egg white-derived peptide QIGLF using renal metabolomics analysis

The kidney is an important target organ in the treatment of hypertension, but the effect of peptide QIGLF with antihypertensive activity on kidneys remains unknown. In the work, we aimed to further understand the hypotensive effects of QIGLF in spontaneously hypertensive rats (SHRs) using widely targeted metabolomics technology to investigate the kidney metabolic profiling variations. After four weeks of oral administration, the results showed different renal metabolomics profiles between QIGLF and model groups. Besides, a total of 10 potential biomarkers were identified, that is, 3-hydroxybutanoate, 20-hydroxyeicosatetraenoic acid, 19(S)-hydroxyeicosatetraenoic acid, 15-oxoETE, L-ornithine, malonate, uridine, uridine 5'-monophosphate, argininosuccinic acid, and N-carbamoyl-L-aspartate. These metabolites might exhibit antihypertensive activity of QIGLF by regulating synthesis and degradation of ketone bodies, arachidonic acid metabolism, pyrimidine metabolism, and arginine biosynthesis. These findings suggest that QIGLF might alleviate hypertension by inhibiting renal inflammation, promoting natriuresis, and regulating renal nitric oxide production.

Extraction optimization and screening of antioxidant peptides from grass carp meat and synergistic-antagonistic effect

Grass carp (Ctenopharyngodon idellus) is one of the three most cultivated freshwater fish around the world, but it is mainly consumed afresh, so only a small part of them are processed into salted fish or snack food. This research was performed to prepare and screen antioxidant peptides from grass carp muscle to promote its high‐value utilization. The parameters of double‐enzyme two‐step hydrolysis were optimized, the peptides with the highest ABTS.⁺ scavenging ability were enriched and identified by Sephadex G‐25 and LC‐Q‐Orbitrap‐MS/MS. The synergistic–antagonistic effect among identified peptides was also investigated. The optimized conditions were hydrolyzed with protamex (10,000 U/g) at pH 8.0, 50°C for 3 h, followed by hydrolysis with alcalase (6,000 U/g) at pH 9.0, 50 °C for 2 h, and the protein–liquid ratio was 4%. The hydrolysates were further fractionated to obtain five fractions, in which fraction 3 (F3) exhibited the strongest ABTS.⁺ and O2·‐ scavenging ability with the IC₅₀ values of 0.11 and 0.47 mg/ml, respectively. Twelve novel antioxidant peptides were identified, in which VAGW possessed the highest activity (139.77 μmol GSH/g). Significantly synergistic effects were observed on the two and three peptides’ combination among VAGW, APPAMW, LFGY, FYYGK, and LLLYK, while the C‐terminal tryptophan (Trp) played an important role in the synergism. This study found that grass carp muscle hydrolysates can be potential natural antioxidants in functional products. The synergistic effects among peptides may provide a perspective for the combined application of peptides.

Effect of extrusion and autoclaving on the biological potential of proteins and naturally-occurring peptides from common beans: Antioxidant and vasorelaxant properties

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Postharvest hardening did not definitively affect bioactivity of bean peptides.

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Peptides from hardened and non-hardened beans showed high vasorelaxant activity.

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Thermal treatment positively affected the biological potential of hardened beans.

Aiming to understand the impact of hardening on the biological potential of bean protein and peptides, we evaluated the antioxidant and vasorelaxant properties of common beans after and before hardening. It was also evaluated the effect of extrusion and autoclaving in the biological potential of hardened beans. In general, hardening caused a reduction from 13.5 to 39.6% on the antioxidant activity of the peptide-rich fractions. On the other hand, hardening did not strongly interfere with the vascular reactivity in thoracic aorta rings, being observed maximal relation varying from 801% to 84.7%. The thermal treatment caused a general increase in the antioxidant and vasorelaxant potential of these fractions, being observed EC₅₀ values ranging from 0.22 mg mL⁻¹ to 0.26 mg mL⁻¹. We can conclude that hardening did not seem to affect definitively the bioactivity of the obtained peptide-rich fractions. Finally, this study allows suggesting practical applications of extrusion as a thermal process in the production of functional food ingredients, and as ready-to-eat products presenting nutraceutical potential. In addition, autoclaving can be used as a pre-treatment of the hardened grains aiming to use them as whole grains with potentialized benefits for human health.

An updated review on food-derived bioactive peptides: Focus on the regulatory requirements, safety, and bioavailability

Food-derived bioactive peptides (BAPs) are recently utilized as functional food raw materials owing to their potential health benefits. Although there is a huge amount of scientific research about BAPs' identification, purification, characterization, and physiological functions, and subsequently, many BAPs have been marketed, there is a paucity of review on the regulatory requirements, bioavailability, and safety of BAPs. Thus, this review focuses on the toxic peptides that could arise from their primary proteins throughout protein extraction, protein pretreatment, and BAPs' formulation. Also, the influences of BAPs' length and administration dosage on safety are summarized. Lastly, the challenges and possibilities in BAPs' bioavailability and regulatory requirements in different countries were also presented. Results revealed that the human studies of BAPs are essential for approvals as healthy food and to prevent the consumers from misinformation and false promises. The BAPs that escape the gastrointestinal tract epithelium and move to the stomach are considered good peptides and get circulated into the blood using different pathways. In addition, the hydrophobicity, net charge, molecular size, length, amino acids composition/sequences, and structural characteristics of BAPs are critical for bioavailability, and appropriate food-grade carriers can enhance it. The abovementioned features are also vital to optimize the solubility, water holding capacity, emulsifying ability, and foaming property of BAPs in food products. In the case of safety, the possible allergenic and toxic peptides often exhibit physiological functions and could be produced during the hydrolysis of food proteins. It was also noted that the production of iso-peptides bonds and undesirable Maillard reaction might occur during protein extraction, sample pretreatments, and peptide synthesis.

Bioactive Properties of Peptides and Polysaccharides Derived from Peanut Worms: A Review

Peanut worms (Sipunculids) are unsegmented marine worms that usually inhabit shallow waters. Peanut worms are good source of bioactive compounds including peptides and polysaccharides. Many recent studies have investigated the bioactive properties of peptides and polysaccharides derived from peanut worms in order to enhance their applications in food and pharmaceutical industries. The peptides and polysaccharides isolated from peanut worms have been reported to possess anti-hypertensive, anti-oxidant, immunomodulatory, anti-inflammatory, anti-cancer, anti-hypoxia and wound healing activities through the modulation of various molecular mechanisms. Most researchers used in vitro, cell culture and animal models for the determination of bioactivities of peanut worm derived compounds. However, studies in humans have not been performed considerably. Therefore, it is important to conduct more human studies for better utilization of marine bioactive compounds (peptides and polysaccharides) derived from peanut worms. This review mainly focuses on the bioactive properties of peptides and polysaccharides of peanut worms and their molecular mechanisms.

Royal Jelly Proteins and Their Derived Peptides: Preparation, Properties, and Biological Activities

Royal jelly, also called bee milk, is a source of high-quality proteins. Royal jelly proteins serve as not only a rich source of essential amino acids and functional donors but also an excellent substrate for preparing bioactive peptides. Most naturally occurring bioactive peptides in royal jelly are antibacterial, while peptides derived from proteolytic reactions are shown to exert antihypertensive, antioxidative, and anti-aging activities. Further studies are warranted to characterize the functional properties of major royal jelly proteins and peptides, to explore the preparation of bioactive peptides and the potential novel activities, to improve their bioavailability, to enhance the production efficiency for commercial availability, and finally to open up new applications for royal jelly as a functional food and potential therapeutic agent.

A heuristic, computer-driven and top-down approach to identify novel bioactive peptides: A proof-of-principle on angiotensin I converting enzyme inhibitory peptides

Bioactive peptides are short peptides (3-20 amino acid residues in length) endowed of specific biological activities. The identification and characterization of bioactive peptides of food origin are crucial to better understand the physiological consequences of food, as well as to design novel foods, ingredients, supplements, and diets to counteract mild metabolic disorders. For this reason, the identification of bioactive peptides is also relevant from a pharmaceutical standpoint. Nevertheless, the systematic identification of bioactive sequences of food origin is still challenging and relies mainly on the so defined "bottom-up" approaches, which rarely results in the total identification of most active sequences. Conversely, "top-down" approaches aim at identifying bioactive sequences with certain features and may be more suitable for the precise identification of very potent bioactive peptides. In this context, this work presents a top-down, computer-assisted and hypothesis-driven identification of potent angiotensin I converting enzyme inhibitory tripeptides, as a proof of principle. A virtual library of 6840 tripeptides was screened in silico to identify potential highly potent inhibitory peptides. Then, computational results were confirmed experimentally and a very potent novel sequence, LMP was identified. LMP showed an IC₅₀ of 15.8 and 6.8 µM in cell-free and cell-based assays, respectively. In addition, a bioinformatics approach was used to search potential food sources of LMP. Yolk proteins were identified as a possible relevant source to analyze in further experiments. Overall, the method presented may represent a powerful and versatile framework for a systematic, high-throughput and top-down identification of bioactive peptides.

Environment-friendly utilization of squid pen with water: Production of β-chitin nanofibers and peptides for lowering blood pressure

Chitin, an abundant biopolymer on Earth, represents a resource for sustainable functional materials. However, traditional β-chitin production methods involve alkaline treatment at approximately 90 °C for its separation from the protein, thus not suitable as a functional peptide, as it is mixed with an alkaline aqueous solution. This study examined the conversion of squid pen into solid β-chitin and water-soluble peptides using only water at temperatures of 150-250 °C for 30-120 min. Solid β-chitin was converted to its nanofiber form and the physicochemical properties of the β-chitin nanofibers were almost the same as those produced by the traditional method. Because this method uses only water, the protein in the squid pen may also be a functional peptide for lowering blood pressure, by inhibiting the Angiotensin-1 converting enzyme. High-temperature water treatment is a promising environment-friendly technique for complete utilization of squid pen components, including β-chitin and protein.

Engineering Concanavalin B to Release Bioactive Peptides against Metabolic Syndrome

Metabolic syndrome is a severe public health issue characterized by multiple metabolic disturbances. Current treatments prescribe a particular drug for each of them, producing multiple side effects. As a first step towards a more integral approach, we applied our recently described methodology to design single proteins, based in the Concanavalin B scaffold (1CNV), that contain several bioactive peptides (BPs), including antioxidant and lipid-lowering activities as well as inhibitors of dipeptidyl peptidase IV (DPPIV) and the angiotensin converting enzyme. Modified Concanavalin (CNV44), the designed protein that showed the best in silico properties, was expressed in high yields in E. coli and purified to homogeneity. After in vitro digestion with gastrointestinal enzymes, all the biological activities tested where higher in CNV44 when compared to the non-modified protein 1CNV, or to other previous reports. The results presented here represent the first in vitro evidence of a modified protein with the potential to treat metabolic syndrome and open the venue for the design of proteins to treat other non-communicable diseases.

A Review on Health-Promoting, Biological, and Functional Aspects of Bioactive Peptides in Food Applications

Food-derived bioactive peptides are being used as important functional ingredients for health-promoting foods and nutraceuticals in recent times in order to prevent and manage several diseases thanks to their biological activities. Bioactive peptides are specific protein fractions, which show broad applications in cosmetics, food additives, nutraceuticals, and pharmaceuticals as antimicrobial, antioxidant, antithrombotic, and angiotensin-I-converting enzyme (ACE)-inhibitory ingredients. These peptides can preserve consumer health by retarding chronic diseases owing to modulation or improvement of the physiological functions of human body. They can also affect functional characteristics of different foods such as dairy products, fermented beverages, and plant and marine proteins. This manuscript reviews different aspects of bioactive peptides concerning their biological (antihypertensive, antioxidative, antiobesity, and hypocholesterolemic) and functional (water holding capacity, solubility, emulsifying, and foaming) properties. Moreover, the properties of several bioactive peptides extracted from different foods as potential ingredients to formulate health promoting foods are described. Thus, multifunctional properties of bioactive peptides provide the possibility to formulate or develop novel healthy food products.