Blue Whiting (Micromesistius poutassou) Protein Hydrolysates Increase GLP-1 Secretion and Proglucagon Production in STC-1 Cells Whilst Maintaining Caco-2/HT29-MTX Co-Culture Integrity.

Inducing the feeling of fullness via the regulation of satiety hormones presents an effective method for reducing excess energy intake and, in turn, preventing the development of obesity. In this study, the ability of blue whiting soluble protein hydrolysates (BWSPHs) and simulated gastrointestinal digested (SGID) BWSPHs, to modulate the secretion and/or production of satiety hormones, such as glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK) and peptide YY (PYY), was assessed in murine enteroendocrine STC-1 cells. All BWSPHs (BW-SPH-A to BW-SPH-F) (1.0% w/v dw) increased active GLP-1 secretion and proglucagon production in STC-1 cells compared to the basal control (Krebs-Ringer buffer) (p < 0.05). The signaling pathway activated for GLP-1 secretion was also assessed. A significant increase in intracellular calcium levels was observed after incubation with all BWSPHs (p < 0.05) compared with the control, although none of the BWSPHs altered intracellular cyclic adenosine monophosphate (cAMP) concentrations. The secretagogue effect of the leading hydrolysate was diminished after SGID. Neither pre- nor post-SGID hydrolysates affected epithelial barrier integrity or stimulated interleukin (IL)-6 secretion in differentiated Caco-2/HT-29MTX co-cultured cells. These results suggest a role for BWSPH-derived peptides in satiety activity; however, these peptides may need to be protected by some means to avoid loss of activity during gastrointestinal transit.

Physicochemical and functional properties of Alcalase-extracted protein hydrolysate from oil palm leaves.

BACKGROUND: The oil palm tree produces 90% of wastes and the limited usage of these wastes causes a major disposal problem in the mills. Nevertheless, these by-products have a large amount of nutritional components. Thus, the present study aimed to determine the physicochemical and functional properties of protein hydrolysates (PH) from oil palm leaves (OPL) extracted using different concentrations of Alcalase (0-10%) at 2 h of hydrolysis time. RESULTS: Fourier transform infrared spectral analyses showed that the enzymatic hydrolysis altered functional groups of OPL where a secondary amine was present in the PH. Changes were also observed in the thermal stability where the enthalpy heat obtained for PH (933.93-1142.57 J g-1 ) was much lower than OPL (7854.11 J g-1 ). The results showed that the PH extracted by 8% Alcalase exhibited absolute zeta potential, as well as a high emulsifying activity index (70.64 m2  g-1 of protein) and emulsion stability index (60.58 min). Furthermore, this PH showed higher solubility (96.32%) and emulsifying properties compared to other PHs. It is also comparable with commercial plant proteins, indicating that 8% Alcalase is an optimum concentration for hydrolysis. CONCLUSION: In summary, the physicochemical and functional properties of PH extracted from OPL showed good functional properties, suggesting that it can be used as an alternative plant protein in food industries. © 2021 Society of Chemical Industry.

Oyster Hydrolysates Attenuate Muscle Atrophy via Regulating Protein Turnover and Mitochondria Biogenesis in C2C12 Cell and Immobilized Mice.

Sarcopenia, also known as skeletal muscle atrophy, is characterized by significant loss of muscle mass and strength. Oyster (Crassostrea gigas) hydrolysates have anti-cancer, antioxidant, and anti-inflammation properties. However, the anti-sarcopenic effect of oyster hydrolysates remains uninvestigated. Therefore, we prepared two different oyster hydrolysates, namely TGPN and PNY. This study aimed to determine the anti-muscle atrophy efficacy and molecular mechanisms of TGPN and PNY on both C2C12 cell lines and mice. In vitro, the TGPN and PNY recovered the dexamethasone-induced reduction in the myotube diameters. In vivo, TGPN and PNY administration not only improved grip strength and exercise endurance, but also attenuated the loss of muscle mass and muscle fiber cross-sectional area. Mechanistically, TGPN and PNY increased the expression of protein synthesis-related protein levels via phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of the rapamycin pathway, and reduced the expression of protein degradation-related protein levels via the PI3K/Akt/forkhead box O pathway. Also, TGPN and PNY stimulated NAD-dependent deacetylase sirtuin-1(SIRT1), peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), nuclear respiratory factor 1,2, mitochondrial transcription factor A, along with mitochondrial DNA content via SIRT1/PGC-1α signaling. These findings suggest oyster hydrolysates could be used as a valuable natural material that inhibits skeletal muscle atrophy via regulating protein turnover and mitochondrial biogenesis.

Seaweed Protein Hydrolysates and Bioactive Peptides: Extraction, Purification, and Applications.

Seaweeds are industrially exploited for obtaining pigments, polysaccharides, or phenolic compounds with application in diverse fields. Nevertheless, their rich composition in fiber, minerals, and proteins, has pointed them as a useful source of these components. Seaweed proteins are nutritionally valuable and include several specific enzymes, glycoproteins, cell wall-attached proteins, phycobiliproteins, lectins, or peptides. Extraction of seaweed proteins requires the application of disruptive methods due to the heterogeneous cell wall composition of each macroalgae group. Hence, non-protein molecules like phenolics or polysaccharides may also be co-extracted, affecting the extraction yield. Therefore, depending on the macroalgae and target protein characteristics, the sample pretreatment, extraction and purification techniques must be carefully chosen. Traditional methods like solid-liquid or enzyme-assisted extraction (SLE or EAE) have proven successful. However, alternative techniques as ultrasound- or microwave-assisted extraction (UAE or MAE) can be more efficient. To obtain protein hydrolysates, these proteins are subjected to hydrolyzation reactions, whether with proteases or physical or chemical treatments that disrupt the proteins native folding. These hydrolysates and derived peptides are accounted for bioactive properties, like antioxidant, anti-inflammatory, antimicrobial, or antihypertensive activities, which can be applied to different sectors. In this work, current methods and challenges for protein extraction and purification from seaweeds are addressed, focusing on their potential industrial applications in the food, cosmetic, and pharmaceutical industries.

Purification, Identification, Activity Evaluation, and Stability of Antioxidant Peptides from Alcalase Hydrolysate of Antarctic Krill (Euphausia superba) Proteins.

For utilizing the largest source of marine proteins, Antarctic krill (Euphausia superba) proteins were defatted and hydrolyzed separately using pepsin, alcalase, papain, trypsin, and netrase, and alcalase hydrolysate (EPAH) showed the highest DPPH radical (DPPH·) and hydroxyl radical (HO·) scavenging activity among five hydrolysates. Using ultrafiltration and chromatography methods, fifteen antioxidant peptides were purified from EPAH and identified as Asn-Gln-Met (NQM), Trp-Phe-Pro-Met (WFPM), Gln-Asn-Pro-Thr (QNPT), Tyr-Met-Asn-Phe (YMNF), Ser-Gly-Pro-Ala (SGPA), Ser-Leu-Pro-Tyr (SLPY), Gln-Tyr-Pro-Pro-Met-Gln-Tyr (QYPPMQY), Glu-Tyr-Glu-Ala (EYEA), Asn-Trp-Asp-Asp-Met-Arg-Ile-Val-Ala-Val (NWDDMRIVAV), Trp-Asp-Asp-Met-Glu-Arg-Leu-Val-Met-Ile (WDDMERLVMI), Asn-Trp-Asp-Asp-Met-Glu-Pro-Ser-Phe (NWD-DMEPSF), Asn-Gly-Pro-Asp-Pro-Arg-Pro-Ser-Gln-Gln (NGPDPRPSQQ), Ala-Phe-Leu-Trp-Asn (AFLWA), Asn-Val-Pro-Asp-Met (NVPDM), and Thr-Phe-Pro-Ile-Tyr-Asp-Tyr-Pro-Gln (TFPIYDPQ), respectively, using a protein sequencer and ESI/MS. Among fifteen antioxidant peptides, SLPY, QYPPMQY and EYEA showed the highest scavenging activities on DPPH· (EC50 values of 1.18 ± 0.036, 1.547 ± 0.150, and 1.372 ± 0.274 mg/mL, respectively), HO· (EC50 values of 0.826 ± 0.027, 1.022 ± 0.058, and 0.946 ± 0.011 mg/mL, respectively), and superoxide anion radical (EC50 values of 0.789 ± 0.079, 0.913 ± 0.007, and 0.793 ± 0.056 mg/mL, respectively). Moreover, SLPY, QYPPMQY and EYEA showed strong reducing power, protective capability against H2O2-damaged plasmid DNA, and lipid peroxidation inhibition ability. Furthermore, SLPY, QYPPMQY, and EYEA had high stability under temperatures lower than 80 °C, pH values ranged from 6-8, and simulated GI digestion for 180 min. The results showed that fifteen antioxidant peptides from alcalase hydrolysate of Antarctic krill proteins, especially SLPY, QYPPMQY and EYEA, might serve as effective antioxidant agents applied in food and health products.

Characterization of Protein Hydrolysates from Fish Discards and By-Products from the North-West Spain Fishing Fleet as Potential Sources of Bioactive Peptides.

Fish discards and by-products can be transformed into high value-added products such as fish protein hydrolysates (FPH) containing bioactive peptides. Protein hydrolysates were prepared from different parts (whole fish, skin and head) of several discarded species of the North-West Spain fishing fleet using Alcalase. All hydrolysates had moisture and ash contents lower than 10% and 15%, respectively. The fat content of FPH varied between 1.5% and 9.4% and had high protein content (69.8-76.6%). The amino acids profiles of FPH are quite similar and the most abundant amino acids were glutamic and aspartic acids. All FPH exhibited antioxidant activity and those obtained from Atlantic horse mackerel heads presented the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, reducing power and Cu2+ chelating activity. On the other hand, hydrolysates from gurnard heads showed the highest ABTS radical scavenging activity and Fe2+ chelating activity. In what concerns the α-amylase inhibitory activity, the IC50 values recorded for FPH ranged between 5.70 and 84.37 mg/mL for blue whiting heads and whole Atlantic horse mackerel, respectively. α-Glucosidase inhibitory activity of FPH was relatively low but all FPH had high Angiotensin Converting Enzyme (ACE) inhibitory activity. Considering the biological activities, these FPH are potential natural additives for functional foods or nutraceuticals.

Collagen Hydrolysate Prepared from Chicken By-Product as a Functional Polymer in Cosmetic Formulation.

Chicken stomachs can be processed into collagen hydrolysate usable in cosmetic products. The aim of the study was to verify the effects of a carbopol gel formulation enriched with 1.0% (w/w) chicken hydrolysate on the properties of the skin in the periorbital area after regular application twice a day for eight weeks in volunteers ageed 50 ± 9 years. Skin hydration, transepidermal water loss (TEWL), skin elasticity and skin relief were evaluated. Overall, skin hydration increased by 11.82% and 9.45%, TEWL decreased by 25.70% and 17.80% (always reported for the right and left area). Generally, there was an increase in skin elasticity, a decrease in skin roughness, as the resonance times decreased by 85%. The average reduction of wrinkles was 35.40% on the right and 41.20% on the left. For all results, it can be seen that the longer the cosmetic gel formulation is applied, the better the results. Due to the positive effect on the quality and functionality of the skin, it is possible to apply the cosmetic gel formulation in the periorbital area. The advantage of the product with chicken collagen hydrolysate is also the biocompatibility with the skin and the biodegradability of the formulation.

Tartary buckwheat protein hydrolysates enhance the salt tolerance of the soy sauce fermentation yeast Zygosaccharomyces rouxii.

Supplementation of protein hydrolysate is an important strategy to improve the salt tolerance of soy sauce aroma-producing yeast. In the present study, Tartary buckwheat protein hydrolysates (BPHs) were prepared and separated by ultrafiltration into LM-1 (<1 kDa) and HM-2 (1-300 kDa) fractions. The supplementation of HM-2 fraction could significantly improve cell growth and fermentation of soy sauce aroma-producing yeast Zygosaccharomyces rouxii As2.180 under high salt (12%, w/w) conditions. However, the LM-1 fraction inhibited strain growth and fermentation. The addition of HM-2 promoted yeast cell accumulation of K+, removal of cytosolic Na+ and accumulation of glycerol. Furthermore, the HM-2 fraction improved the cell membrane integrity and mitochondrial membrane and decreased intracellular ROS accumulation of the strain. The above results indicated that the supplementation of BPHs with a molecular weight of 1-300 kDa is a potentially effective and feasible strategy for improving the salt tolerance of soy sauce aroma-producing yeast Z. rouxii.

Protein hydrolysates from anchovy waste: purification and chemical characterization.

The aim of this study is to prompt the recovery of industrial by-products through the production of new functional foods; it takes advantage from new throughput technologies with low environmental impact and high economic sustainability. In the field of fish processing, in order to recover the worthy protein-rich fish waste, residues from the production of Anchovies (Engraulis encrasicolus) have been converted into hydrolysate through enzymatic treatment. The obtained hydrolysate product showed a promising biological and nutritional content made by differently sized peptides and free amino acids endowed with assessed benefic effects. The study showed the possibility to produce a dry powder with an activity water (aw) of 0.3-0.5 and an essential amino acids (EAA) fraction of 42.0% over the total amino acids (TAAs). These results pave the way to the smart recovery of commercial products featured by high nutritional value, either as stand-alone items or as components of functional foods.

Purification and Identification of Pine Nut (Pinus yunnanensis Franch.) Protein Hydrolysate and Its Antioxidant Activity in Vitro and in Vivo.

In this study, the pine nut (Pinus yunnanensis Franch.) protein was hydrolyzed by alkaline protease and trypsin to prepare pine nut protein hydrolysate (PNPH). The chemical, intracellular and in vivo antioxidant capacity of PNPH were evaluated. PNPH owned the ability of scavenging free radicals, and it could protect the HepG2 cells from oxidative damage by preserving cell viability. Moreover, PNPH could reduce the malondialdehyde (MDA) content and improved the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in serum, heart and liver of aging mice induced by D-galactose. Further, the PNPH was stepwise purified and identified, and 15 peptides were identified from purified fraction in PNPH. The three-dimension structures of identified peptides were predicted. Among all identified peptides, peptide 3, 7, 8 and 11 were presumed to possess good antioxidant activity. Overall, PNPH and purified peptides isolated from PNPH have potential application prospects in the field of natural antioxidants and anti-aging functional foods.

Bioactive peptides attenuate cardiac apoptosis in spontaneously hypertensive rat hearts through activation of autophagy and mitochondrial biogenesis pathway.

Alcalase potato protein hydrolysate (APPH) might have a very important role in therapeutic effects. This study aims to examine the beneficial effects of bioactive peptides (DIKTNKPVIF [DI] and IF) from APPH supplement in the regulation of cardiac apoptosis, autophagy, and mitochondrial biogenesis pathway in spontaneously hypertensive rats (SHR). We have investigated ejection fraction, fractional shortening, Tunel assay, apoptosis, autophagy, and mitochondrial biogenesis pathway marker expression to show the efficacy of bioactive peptides in an SHR model. Bioactive peptides significantly upregulate ejection fraction and fractional shortening in SHR rats. SHR rats exhibited higher protein expression of apoptotic markers such as BAD, cytochrome c, and caspase 3. Finally, the bioactive peptides upregulate survival proteins (p-AKT/p-PI3K), autophagy (Beclin1/LC3B), and mitochondrial biogenesis (p-AMPKα/SIRT1/PGC1α/p-Foxo3a/Nrf2/CREB) marker expressions compared with the SHR groups. In summary, the bioactive peptides protect the heart tissues through the activation of autophagy and mitochondrial biogenesis pathway and thereby attenuate cardiac apoptosis in a spontaneously hypertensive rat model.

Antioxidant activities of peptide hydrolysates obtained from the seeds of Treculia africana Decne (African breadfruit).

Protein hydrolysates usually possess higher nutritive value than an equivalent mixture of free amino acids. This study was aimed at determining the antioxidant activities of protein hydrolysates of Treculia africana seeds. Soluble protein was isolated from Treculia africana seed flour by alkaline solubilization and acid precipitation, and further hydrolyzed with three proteases (trypsin, pancreatin and pepsin) individually and in a sequential two- and three-protease systems. Antioxidant activities (DPPH, FRAP and lipid peroxidation) of the hydrolysates were investigated. Hydrolysates from Treculia africana seed protein showed varying degree of hydrolysis, pancreatin hydrolysates had the highest (94.92%) and pancreatin-pepsin hydrolysates had the least (6.59%). Pancreatin proved to be the most efficient protease for hydrolyzing Treculia africana protein with a high protein recovery of 156.06 mg/ml. Its hydrolysates exhibited the highest DPPH scavenging activity (71.02%) and had a high radical-mediated peroxidation of oleic acid. Likewise, pancreatin hydrolysates as well as trypsin-pancreatin hydrolysates showed the highest FRAP activity (37.17 and 38.52 µg/ml BHA, respectively). Pancreatin hydrolysates showed significant higher (p < 0.05) antioxidant potentials than other hydrolysates of T. africana seed protein. These findings showed the potential use of Treculia africana hydrolysates as antioxidants in reducing food spoilage and management of oxidative stress-related metabolic disorders.

Transdermal permeation effect of collagen hydrolysates of deer sinew on mouse skin, ex vitro, and antioxidant activity, increased type I collagen secretion of percutaneous proteins in NIH/3T3 cells.

BACKGROUND: The collagen hydrolysates as a cosmetic material have already been wide application. At present, few studies concern with transdermal behavior of collagen hydrolysates in vitro. OBJECTIVE: Deer sinew contains rich collagen with a content of 82.12%. Thus, this article mainly studies the transdermal effect of collagen hydrolysates of deer sinew (DSCH) on mouse skin, ex vitro, and to explore skincare protection of percutaneous proteins. METHODS: Collagen hydrolysates of deer sinew were extracted by 0.2% HCl and a two-step enzymatic method of pepsin-trypsin. The content of 17 amino acids of DSCH was detected by precolumn derivatization RP-HPLC. Using Franz diffusion cell systems studied the transdermal effect of DSCH and then examined the percutaneous rate and molecular weight distribution of percutaneous proteins (PP). Further, we studied the bioactivity of PP in vitro, such as the total antioxidant capacity and collagen secretion in NIH/3T3 cells. RESULTS: About 8.0% DSCH could penetrate skin of mouse, the molecular weight of PP mainly distributed in 5 ~ 13 kDa, accounted for 91.55%. Compared with the antioxidant activity of DSCH, PP had obvious antioxidant activity of scavenging radical cation. Meanwhile, PP promoted cell proliferation and collagen I secretion in fibroblast cells; however, level of type III collagen has no change. CONCLUSION: Collagen hydrolysates of deer sinew may be used as cosmetic material to protect the skin from oxidative stress, to prevent premature skin aging.

A Mini-Review on Brewer's Spent Grain Protein: Isolation, Physicochemical Properties, Application of Protein, and Functional Properties of Hydrolysates.

There is a growing demand in reusing agro-industrial waste to enrich food proteins and develop new protein-related products. Brewer's spent grain (BSG), the byproducts generated from the processing of beer-brewing industry, is rich in abundant protein (26 to 30%) with good physicochemical properties and nutritional benefits. BSG is mainly composed of four proteins including hordein, gluten, globulin, and albumin. The methods for extracting protein from BSG mainly include alkali extraction, ultrasonic-assisted extraction, and organic solvent extraction, among others. However, little researches have described the functional properties of Brewer's spent grain protein (BSGP) and how it can be improved by enzymatic modification. Additionally, BSG protein hydrolysates (BSGPHs) have good bioactivities, mainly including antioxidant, antiinflammatory, and angiotensin-I-converting enzyme inhibitory activities, among others. Based on the above situation, this review provides a comprehensive overview about the isolation, physicochemical features, application of the BSGP. In addition, the functional properties and biological activities of BSGPHs are also emphasized. The purpose of this review is to provide an up-to-date summary of BSGP research, and to broaden the market potential of this emerging protein in food industry. Besides, this review provides a reference to study the use of BSGP or hydrolysates for a variety of purposes in-depth, including pharmaceutical, food, and industrial applications.

In Vivo Hepatoprotective Effects of a Peptide Fraction from Krill Protein Hydrolysates against Alcohol-Induced Oxidative Damage.

BACKGROUND: Krill (Euphausia superba) represent the largest animal biomass on earth, and are a rich source of high-quality protein with essential amino acids. Krill-derived peptides are renowned for their antioxidant activities. Hence, these peptides may have protective effects against oxidative stress. Alcoholic liver disease is a prevalent cause of death worldwide. The present study explores the hepatoprotective effects of krill peptide hydrolysate fractions against ethanol-induced liver damage in BALB/c mice. METHODS: Hydrolysis was carried out by mimicking the gastrointestinal digestion environment and the filtrate was fractionated based on molecular weight (<1 kDa, 1-3 kDa, and >3 kDa). The 1-3 kDa fraction (KPF), which indicated the highest antioxidant effect, was further investigated for its effect on weight and survival rate increase in mice and its influence on serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and liver cholesterol levels. Moreover, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) levels were measured, followed by Nrf2 and HO-1 expression. Histopathology studies were conducted to assess hepatic tissue damage. RESULTS: KPF enhanced the weight and survival rate of mice while reducing serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and liver cholesterol levels. Moreover, KPF upregulated SOD, CAT, and GPx in liver tissues, while downregulating tumor necrosis factor α and interleukin-6 mRNA expression. KPF further increased Nrf2 and HO-1 expression and suppressed ethanol-induced apoptotic proteins in the liver. Histopathology of KPF-treated mice showed less hepatic tissue damage compared to ethanol-treated mice. CONCLUSIONS: Hydrolysates and bioactive peptides prepared from krill can be employed as functional foods to enhance liver function and health. Further investigations of KPF could lead to the development of functional foods.

Angiotensin-converting enzyme inhibiting ability of ethanol extracts, steviol glycosides and protein hydrolysates from stevia leaves.

Efficient treatment of hypertension is vital. The inhibition of angiotensin-converting enzyme activity has been one of the major strategies for treating hypertension. The ethanol extract of stevia leaves, steviol glycosides (with 95% purity; natural sweeteners widely used in the food industry) isolated from the ethanol extract and stevia leaf protein hydrolysates inhibited 26.60%, 59.56% and 74.38% of angiotensin-converting enzyme activities, respectively. Their effect was dose-dependent, which can be beneficial for avoiding hypertension or hypotension just by the proper control of the amount of their intake, and it was found to be superior to that of pharmaceutical drugs. A sensory test indicated that the application of the mixtures of steviol glycosides and stevia protein hydrolysates to decaffeinated coffee or tea as well as a formulated peanut protein drink was found to be well accepted, and an animal test showed that they had a significantly antihypertensive effect in spontaneously hypertensive rats. Steviol glycosides and stevia leaf protein hydrolysates can be good ingredients for making functional or healthy food products or beverages targeted for the prevention or treatment of hypertension.

Hydrolyzed Collagen-Sources and Applications.

Hydrolyzed collagen (HC) is a group of peptides with low molecular weight (3-6 KDa) that can be obtained by enzymatic action in acid or alkaline media at a specific incubation temperature. HC can be extracted from different sources such as bovine or porcine. These sources have presented health limitations in the last years. Recently research has shown good properties of the HC found in skin, scale, and bones from marine sources. Type and source of extraction are the main factors that affect HC properties, such as molecular weight of the peptide chain, solubility, and functional activity. HC is widely used in several industries including food, pharmaceutical, cosmetic, biomedical, and leather industries. The present review presents the different types of HC, sources of extraction, and their applications as a biomaterial.

Bioactivity of hydrolysates obtained from bovine casein using artichoke (Cynara scolymus L.) proteases.

The objective of this work was to obtain casein hydrolysates with aspartic proteinases present in extracts from the artichoke flower (Cynara scolymus L.) and evaluate their antioxidant, antimicrobial, and angiotensin-I converting enzyme (ACE) inhibitory activity in vitro. The casein hydrolysates produced by the action of C. scolymus had elevated antihypertensive and antioxidant activity due to their high hydrophobic peptide content (93.84, 96.58, and 90.54% at 2, 4, and 16 h of hydrolysis, respectively). Hydrolysis time and molecular weight (<3 kDa) had a significant influence on the hypertensive and antioxidant activity of the hydrolysates, which were greater at hydrolysis times of 4 and 16 h and corresponding to the <3 kDa fractions. The <3 kDa fraction of the 16 h hydrolysate had an ACE inhibitory activity with a half-maximal inhibitory concentration (IC50) of 71.77 µg peptides per mL; DPPH and ABTS•+ radical scavenging activities of 6.27 µM and 6.21 mM Trolox equivalents per mg of peptides, respectively; and iron (II) chelation activity with an IC50 of 221.49 µg of peptides per mL. Antimicrobial activity against Enterococcus faecalis was also observed in the hydrolysates. From the peptide sequences identified in the hydrolysates, we detected 22 peptides (from the BIOPEP database) that were already in their bioactive form (AMKPWIQPK, AMKPWIQPKTKVIPYVRYL, ARHPHPHLSFM, DAQSAPLRVY, FFVAPFPEVFGK, GPVRGPFPII, KVLPVPQK, LLYQEPVLGPVRGPFPIIV, MAIPPKKNQDK, NLHLPLPLL, PAAVRSPAQILQ, RELEELNVPGEIVESLSSSEESITR, RPKHPIKHQ, RPKHPIKHQGLPQEVLNENLLRF, SDIPNPIGSENSEK, TPVVVPPFLQP, VENLHLPLPLL, VKEAMAPK, VLNENLLR, VYPFPGPIH, VYQHQKAMKPWIQPKTKVIPYVRY, VYQHQKAMKPWIQPKTKVIPYVRYL) and are reported to display antioxidant, antimicrobial, and ACE inhibitory activity. We also identified 12,116, 14,513, and 25,169 peptide sequences in the hydrolysates at 2, 4, and 16 h, respectively, that were contained in the primary sequence, and these are reported to display ACE inhibitory, antioxidant, dipeptidyl peptidase IV inhibition, antithrombotic, opioid, immunomodulation, antiamnesic, anticancer, chelating, and hemolytic bioactivity.

Identification of A Novel Antibacterial Peptide from Atlantic Mackerel belonging to the GAPDH-Related Antimicrobial Family and Its In Vitro Digestibility.

The Atlantic mackerel, Scomber scombrus, is one of the most fished species in the world, but it is still largely used for low-value products, such as bait; mainly for crustacean fishery. This resource could be transformed into products of high value and may offer new opportunities for the discovery of bioactive molecules. Mackerel hydrolysate was investigated to discover antibacterial peptides with biotechnological potential. The proteolytic process generated a hydrolysate composed of 96% proteinaceous compounds with molecular weight lower than 7 kDa. From the whole hydrolysate, antibacterial activity was detected against both Gram-negative and Gram-positive bacteria. After solid phase extraction, purification of the active fraction led to the identification of 4 peptide sequences by mass spectrometry. The peptide sequence N-KVEIVAINDPFIDL-C, called Atlantic Mackerel GAPDH-related peptide (AMGAP), was selected for chemical synthesis to confirm the antibacterial activity and to evaluate its stability through in vitro digestibility. Minimal inhibitory concentrations of AMGAP revealed that Listeria strains were the most sensitive, suggesting potential as food-preservative to prevent bacterial growth. In addition, in vitro digestibility experiments found rapid (after 20 min) and early digestibility (stomach). This study highlights the biotechnological potential of mackerel hydrolysate due to the presence of the antibacterial AMGAP peptide.

Immunosuppressive effects of protein derivatives from Mucuna pruriens on a streptozotocin-induced type 1 diabetes murine model.

Type 1 diabetes is an autoimmune disease induced by abnormal insulin secretions from ß-cells in pancreas. The present study aimed to investigate the immunosuppressive effects from protein derivatives of Mucuna pruriens on a murine model of Type 1 diabetes. Hydrolyzate and five peptide fractions with different molecular weight were administered orally by 14 days, followed T1D murine model was built by intraperitoneal injection of streptozotocin over 5 days. The mice weight, blood glucose levels, anti-insulin, and anti-pancreatic islet ß-cells antibodies, pro-inflammatory cytokines as tumor necrosis factor alpha and interleukin-6 were determined in four times (0, 15, 30, and 45 day). Mice were sacrificed and pancreatic tissues samples were obtained and staining with hematoxylin and eosin to determine the degree of damage. The study demonstrated immunosuppressive activity in four of the six treatment groups: (a) T1D PPH, (b) T1D F 5-10 kDa, (c) T1D F 3-5 kDa, and (d) T1D F 1-3 kDa. PRACTICAL APPLICATIONS: Due to the high content of native protein in seeds of Mucuna pruriens, studies have reported potential in the elaboration of hydrolysates and peptides with biological activity. These protein derivatives could help in the treatment of immunological disorders that are observed in several chronic non-communicable disease and inflammatory diseases, such as T1D. Activated macrophages and lymphoplasmacytic infiltrate plays a crucial role in the initiation and maintenance of T1D; therefore, several studies has focused to reduce the effector functions of this cells for diminishing the clinical manifestations in inmmunocompromised patients. Thus, this study indicates the potential application of hydrolyzate and peptide fractions of M. pruriens in functional foods and dietary supplements could be developed for the treatment of inflammatory and chronic non-communicable diseases.