Peptide Fractions Research Articles

Evaluation of Antibacterial Activity of Milk Peptides Released during the Growth of Lactobacilli in Milk

The present study is carried out to evaluate the antibacterial peptides released during the growth of lactobacilli in milk. Among 8 isolates of lactobacilli and yoghurt cultures used for study, the yoghurt culture released the maximum quantity of peptides (90 ± 1.25 µg/ml). When tested for antibacterial activity only yoghurt culture filtrate showed the antibacterial potential. Further, yoghurt culture lysate was prepared, which was used to treat the milk to bring in proteolysis. The supernatant obtained after centrifugation of this treated milk was used to partially purify peptides by gel filtration using Sephadex G-50. One of the three fractions (F2) showed antibacterial activity against test organisms, E. coli, Salmonella sp. and Shigella dysentriae. The peptide fraction was incorporated into curd samples inoculated with different lactic cultures and spiked with E. coli to determine antibacterial activity. It was found that peptide showed a bacteriostatic effect on E. coli, and the viable count of it was almost reduced by two log cycles when compared with the control.

Abnormal proteolytic activity profile in plasma of blood donors according to anti-SARS-CoV-2 IgG titer

This work aims to study whether there is a relationship between titer values of anti-SARS-CoV-2 IgG and changes in proteolytic processes. To confirm this hypothesis, we analyzed the content and activity of Matrix Metalloproteinases (MMPs) as well as the concentration and composition of circulating peptide pools in the plasma of blood donors divided into groups on the basis of anti-SARS-CoV-2 IgG titers. The results of gelatin zymography showed the presence of active MMP-2 in donors’ plasma who recovered from COVID-19. In contrast, collagenases and their complexes were detected in the plasma of donors with no anti-SARS-CoV-2 IgG, while their activity was undetectable in some groups of COVID-19 convalescent individuals. The content of MMPs also differed among the donors with different titers of anti-SARS-CoV-2 IgG. Plasma peptide content was identical among the donors' groups, but there were more peptide fractions in plasma peptide pools of COVID-19 convalescent individuals; furthermore, they all were characterized by the presence of peptides with molecular weights less than 920 Da and greater than 1530 Da. We hypothesized a link between proteolytic alterations and peptide fraction composition. Our data need further validation to confirm the relationship between the titer values of anti-SARS-CoV-2 IgG and the severity of the proteolytic imbalance.

Glycation modification of protein hydrolysate from channel catfish (Ictalurus Punetaus) viscera to mitigate undesirable flavor: Unraveling structure and flavor characteristics

To investigate the impacts of glycation modification on the structure and flavor of fish viscera-derived protein hydrolysates, channel catfish viscera was utilized and hydrolyzed by Flavourzyme, followed by glycation with glucosamine, xylose, ribose and glucose, respectively. The structural characteristics, taste and odor of glycated products were evaluated. The results revealed that glycation led to an increase in peptides (<1 kDa) and a decrease in peptide fraction (>5 kDa). UV and fluorescence spectra indicated a gradual rise in absorbance and fluorescence intensity. Glucosamine-induced glycation significantly mitigated bitterness, while enhancing saltiness and umami. GC–MS/MS analysis revealed that glycation led to reduced undesirable odor, and formation of aromatic compounds. LC-MS/MS identified Arg and Lys as the main modification sites. Interestingly, aldehydes were found to modify peptides via carbonyl-amine reaction, leading to decreased fishy odor. The present study contributes to flavor improvement of fish viscera-derived peptides through glycation and high-value utilization of fish viscera.

Natto-derived dipeptide Gln-Gln attenuates scopolamine-induced memory impairment by enhancing cholinergic function in mice

This study investigated the efficacy of natto in counteracting memory impairment induced by scopolamine in mice and identified promising peptides. The peptide fraction prepared from natto fermented for 18 h with Bacillus subtilis var. natto TTCC12 improved memory retention and upregulated hippocampal neuroprotective gene expression, including for choline acetyltransferase (ChAT) and brain-derived neurotrophic factor. Metabolomic analysis revealed that several dipeptides, such as Gln-Leu, Gln-Ile, Gln-Gln, and Ala-Tyr, increased in the blood 60 min after oral administration of the natto peptide fraction in rats. These dipeptides significantly attenuated scopolamine-induced memory impairment and increased brain acetylcholine (ACh) levels. Specifically, Gln-Gln exhibited a dose-dependent improvement by enhancing cholinergic function through increased levels of ACh and ChAT. However, an equimolar amount of Gln, as a free amino acid, showed no significant effects. Therefore, this study demonstrated the potential of natto and its constituents, particularly dipeptides Gln-Gln, in mitigating cognitive impairment.

Proteome characterization of extracellular vesicles from human milk: Uncovering the surfaceome by a lipid-based protein immobilization technology.

Breast milk is an essential source of nutrition and hydration for the infant. In addition, this highly complex fluid is rich in extracellular vesicles (EVs). Here, we have applied a microfluidic technology, lipid-based protein immobilization (LPI) and liquid chromatography with tandem mass spectrometry (LC-MS/MS) to characterize the proteome of human milk EVs. Mature milk from six mothers was subjected to EV isolation by ultracentrifugation followed by size exclusion chromatography. Three of the samples were carefully characterized; suggesting a subset enriched by small EVs. The EVs were digested by trypsin in an LPI flow cell and in-solution digestion, giving rise to two fractions of peptides originating from the surface proteome (LPI fraction) or the complete proteome (in-solution digestion). LC-MS/MS recovered peptides corresponding to 582 proteins in the LPI fraction and 938 proteins in the in-solution digested samples; 400 of these proteins were uniquely found in the in-solution digested samples and were hence denoted "cargo proteome". GeneOntology overrepresentation analysis gave rise to distinctly different functional predictions of the EV surfaceome and the cargo proteome. The surfaceome tends to be overrepresented in functions and components of relevance for the immune system, while the cargo proteome primarily seems to be associated with EV biogenesis.

Bioactive proteins and antioxidant peptides from Litsea cubeba fruit meal: Preparation, characterization and ameliorating function on high-fat diet-induced NAFLD through regulating lipid metabolism, oxidative stress and inflammatory response

Non-alcoholic fatty liver disease (NAFLD) plays an increasingly significant threat to human health. In this study, the processing by-products of Litsea cubeba fruit meal were defatted by ultrasound-assisted methods, then the acetone-precipitated protein of L. cubeba (LCP) was obtained and structural analysis was performed. LCP was hydrolyzed by a two-step sequential hydrolysis method using alcalase and papain. Subsequently, antioxidant peptide fraction (IV2) was isolated and identified from the resultant hydrolysate through membrane ultrafiltration, Sephadex G-15 chromatography, and liquid chromatograph mass spectrometer (LC-MS). Animal experimentation indicated the potential of IV2 to mitigate hepatic steatosis. Moreover, IV2 could effectively reduce oxidative stress-induced damage by modulating the Keap1-Nrf2 pathway to activate downstream heme oxygenase-1 (HO-1) and NAD(P) H quinone oxidoreductase 1 (NQO1). Integrating metabolomics and transcriptomics revealed enrichment in pathways associated with glycerolipid metabolism and fatty acid β-oxidation, suggesting the principal mechanisms underlying IV2's ameliorative effects on NAFLD. Transcriptome sequencing identified 3092 up-regulated and 3010 down-regulated genes following IV2 treatment. Interaction analyses based on different lipid compositions (DELs) and differentially expressed genes (DEGs) indicated that IV2 primarily alleviated hepatic steatosis by modulating peroxisome proliferator-activated receptor α (PPAR-α) related pathways, thereby augmenting fatty acid β-oxidation within liver cells. These results indicate that IV2 shows potential in improving high-fat diet (HFD)-induced NAFLD, with improved fatty acid β-oxidation and reduced triglyceride biosynthesis emerging as underlying mechanisms.

Initial Exploration of the In Vitro Activation of GLP-1 and GIP Receptors and Pancreatic Islet Cell Protection by Salmon-Derived Bioactive Peptides

This study examines the in vitro effects of a soluble protein hydrolysate (SPH) derived from Atlantic salmon (Salmo salar) on incretin receptor activity and pancreatic islet cell protection to explore the mechanisms underlying SPH’s observed benefits on weight loss and metabolic health in overweight individuals. SPH demonstrated a dose-dependent enhancement of glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) receptor activity, with significant increases of 2.4-fold (p &lt; 0.05) and 2.6-fold (p &lt; 0.01) at 10 mg/mL, respectively, compared to the control. Pancreatic islet cell assays showed a substantial proliferation effect, with up to a 57% increase at 50 µL/well, indicating potential protective properties against inflammation-induced cell loss. Notably, the smallest SPH peptide fraction (&lt;1000 Da) exhibited GLP-1 agonist activity comparable to semaglutide, a widely used therapeutic agent, underscoring SPH’s potential efficacy in modulating metabolic pathways. These results suggest that SPH not only enhances key incretin signaling but also promotes islet cell health, positioning it as a promising dietary intervention to improve age-related metabolic health, including the weight gain and underlying adverse metabolic changes frequently encountered through the menopause.

Mitigating aluminum chloride-induced toxicity in Drosophila melanogaster with peptide fractions from Euphorbia species

This study assessed the antioxidative and protective effects of peptide extracts from selected Euphorbia species on Aluminum Chloride (AlCl3)-induced toxicity in Drosophila melanogaster. Euphorbia humifusa (EHU), Euphorbia hirta (EHI), and Euphorbia graminae (EHG) were screened for bioactive peptides. The crude peptide extract and partially purified peptide fractions of all the plants were subjected to preliminary antioxidants activities through 2, 2-diphenyl-1-picrylhyhdrazyl (DPPH), and nitric oxide (NO) scavenging activities. The most active peptide fraction was subjected to biochemical studies using Drosophila melanogaster. Flies were treated with AlCl3 (100 mg/kg diet), peptide fraction (5 and 10 mg/kg diet), and cotreatment of AlCl3 and the fraction, respectively. After treatment, flies were homogenized for the determination of total thiol and Glutathione (non-protein thiol) content, catalase and Glutathione-S-transferase activities, and nitric oxide (nitrite/nitrate) and hydroperoxide levels. The antioxidant screening revealed that the peptide fraction from Euphorbia humifusa (PEHU) was the most significant compared to the control (ascorbic acid). The PEHU (5 and 10 mg/kg diet) maintained the redox status of the flies in the biochemical study. The PEHU significantly counteracted AlCl3-induced reduction in antioxidants (catalase, GST, GSH and Total thiol), increased nitric oxide levels, and acetylcholinesterase activity and prevented behavioral deficits flies. Hence, the peptide fraction of Euphorbia humifusa may shield against the life-threatening effects of free radicals associated with aluminum chloride toxicity.

Brazilian kefir fraction mitigates the Alzheimer-like phenotype in Drosophila melanogaster with β-amyloid overexpression model

Alzheimer’s disease (AD) is a progressive neurodegenerative condition and the primary form of dementia among elderly people. The amyloidogenic hypothesis is the main theory that explains this phenomenon and describes the extracellular accumulation of amyloid beta (Aβ) peptides. Model organisms such as Drosophila melanogaster have been utilized to improve the understanding of this disease and its treatment. This study evaluated the effects of peptide and metabolic fractions of Brazilian kefir on a strain of D. melanogaster that expresses human Aβ peptide 1–42 in the eye. The parameters assessed included ommatidial organization, vacuole area, retinal thickness, and Aβ peptide quantification. The present study revealed that the fractions, particularly the peptidic fraction, significantly reduced the vacuole area and increased the retina thickness in treated flies, indicating an improvement in neurodegeneration phenotype. The peptidic fraction was also found to alter Aβ aggregation dynamics, inhibiting Aβ fibril formation, as revealed by dynamic light scattering. This study demonstrated that kefir fractions, particularly the peptidic fraction < 10 kDa, have the potential to regulate Aβ aggregation and alleviate neurodegeneration in a Drosophila melanogaster AD-like model. These findings suggest that kefir fractions could be viable for the bioprospection of novel drug prototypes for AD treatment, providing valuable insights into strategies targeting Aβ aggregation and neurodegeneration in AD.

Hydrolysates of mare's milk proteins. Immunochemical and physico-chemical characteristics

In recent years, the attention of specialists has been attracted by a significant increase in allergic diseases, especially among children. Enzymatic hydrolysis with the participation of peptidases is considered the most effective measure to reduce the allergenicity of milk proteins. The study of the features of protein proteolysis by various enzymes, aimed at establishing optimal process parameters, is the subject of research in the production of hydrolysates with specified properties: a certain peptide and amino acid profile, reduced antigenic properties. At the same time, for a correct preclinical assessment of the safety and potential effectiveness of specialized food products, it is not enough only to determine the molecular weight distribution of peptide fractions in the composition. A necessary additional and informative indicator of reducing the potential allergenicity of the hydrolysate is the degree of preservation of the antigenic properties of the initial protein (residual antigenicity), determined by immunochemical methods. The preparation and subsequent comprehensive assessment of enzymatic hydrolysates of mare's milk proteins is of considerable interest, since, according to the results of clinical studies, it was suggested that upon allergy to cow's milk proteins mare's milk can be considered hypoallergenic. The purpose of this work was to obtain enzymatic hydrolysates of mare's milk proteins using domestic enzymes and their further physico-chemical and immunochemical characteristics. The object of the study was mare's milk protein obtained from skimmed mare's milk powder as a protein substrate. Two samples of enzymes from various manufacturers of the Russian Federation were used in the work. The results of the conducted studies show that the peptide profiles of hydrolysates vary greatly depending on the enzyme used, however, the multiplicity of antigenicity reduction practically does not depend on the nature of the enzyme, and does not depend on an increase in the enzyme/substrate ratio. The peptide profile and the multiplicity of reducing the antigenicity of hydrolysates of mare's milk proteins are influenced by ultrafiltration treatment of the obtained hydrolysates, which allows reducing the content of antigenic structures in the final product by several orders of magnitude.

Immunomodulatory, Anticancer, and Antioxidative Activities of Bioactive Peptide Fractions from Enzymatically Hydrolyzed White Jellyfish (Lobonema smithii).

This study aimed to develop bioactive protein hydrolysates from low-value edible jellyfish obtained from local fisheries using enzymatic hydrolysis. Fresh white jellyfish were hydrolyzed using several commercial proteases, including alcalase (WJH-Al), flavourzyme (WJH-Fl), and papain (WJH-Pa). The antioxidant, immunomodulatory, and anticancer activities of these white jellyfish hydrolysates (WJH) were investigated. The results demonstrated that the crude WJH exhibited strong antioxidant properties, including DPPH, ABTS, and hydroxyl radical scavenging activities, as well as ferric-reducing antioxidant power. Additionally, the hydrolysates showed notable immunomodulatory activity. However, all WJH samples displayed relatively low ability to inhibit HepG2 cell proliferation at the tested concentrations. Among the hydrolysates, WJH-Pa demonstrated the highest antioxidant and immunomodulatory activities and was therefore selected for further bioactive peptide isolation and characterization. Ultrafiltration membranes with three molecular weight (MW) cut-offs (1, 3, 10 kDa) were used for peptide fractionation from WJH-Pa. Six potential peptides were identified with the MW range of 1049-1292 Da, comprising 9-12 residues, which exhibited strong antioxidant and immunomodulatory activities.

Controlled release and biological properties of prochitosomes loaded with Arthrospira derived peptides: Membrane stability, chemical, morphological and structural monitoring

In this study, the effects of chitosan-coating on maintaining the integrity and stability of the membrane, structural, and morphological changes, and the release of loaded peptides inside nanoliposomes during various in vitro release, thermal, freeze-thaw, shear, and dehydration (spray-drying) tensions were evaluated. Among different peptidic fractions (100, 30, and 10 kDa), the Arthrospira derived PF-30 kDa showed a higher nutritional and biological value. PF-30kDa was loaded successfully (EE ~ 90 %) inside nanoliposomes (NLs) and its stabilization was done with chitosan coating (0.1–0.8 %). Nanochitosomes (NCs-0.4 %) had more structural stability (size, EE, and biological activity) at different temperatures, freeze-thaw tension, and digestive system. The placement of peptides in the vesicle structure was confirmed by FTIR analysis. Also, the changes in the morphological states, agglomeration, or destruction of the liposome membrane (SEM, AFM, and TEM) were evaluated before and after the tensions. Membrane coating led to the transformation of freeze-dried liposomes (FD-NLs) from thin, porous, and fragile layers to thick plates, rough and resistant structures (FD-NCs). These characteristics led to maintaining physical stability, homogeneity, zeta potential, and EE of nanoparticles (freeze and spray-dried) after reconstitution. The results of this study will effectively contribute to the production of solidified delivery systems with long-term durability, bioavailability, and biological activity of loaded nutrients and drugs.

By-Products Valorization: Peptide Fractions from Milk Permeate Exert Antioxidant Activity in Cellular and In Vivo Models.

The discarding of agri-food by-products is a stringent problem due to their high environmental impact. Recovery strategies can lead to a reduction of waste and result in new applications. Agri-food waste represents a source of bioactive molecules, which could promote health benefits. The primary goal of this research has been the assessment of the antioxidant activity of milk permeate, a dairy farm by-product, and the isolation and identification of peptide fractions endowed with antioxidant activity. The chromatographic extraction of the peptide fractions was carried out, and the peptides were identified by mass spectrometry. The fractions showed radical scavenging activity in vitro. Moreover, the results in the Caco-2 cell model demonstrated that the peptide fractions were able to protect from oxidative stress by stimulating the Keap1/Nrf2 antioxidant signaling pathway, increasing the transcription of antioxidant enzymes. In addition, the bioactive peptides can affect cellular metabolism, increasing mitochondrial respiration. The action of the peptide fractions was also assessed in vivo on a zebrafish model and resulted in the protection of the whole organism from the adverse effects of acute cold stress, highlighting their strong capability to protect from an oxidative insult. Altogether, the results unveil novel recovery strategies for food by-products as sources of antioxidant bioactive peptides that might be utilized for the development of functional foods.

Isolation of Bacillus altitudinis 5-DSW with Protease Activity from Deep-Sea Mineral Water and Preparation of Functional Active Peptide Fractions from Chia Seeds.

In this study, we successfully isolated Bacillus strains with high protease activity from deep-sea mineral water in Korea and used them to obtain functional peptide fractions from chia seeds. The obtained Bacillus strains showed a high similarity of 99% with B. altitude with a long rod type (named B. altitudinis 5-DSW) and high protease activity at 40 °C, and 70% of the activity remained even at 70 °C. The defatted chia seed protein (15-50 kDa) was treated with crude protease from B. altitudinis 5-DSW and digested into small peptides below 20 kDa. The obtained chia seed peptides showed 3 times and 1.5 times higher antioxidant activity in DPPH and ABT radical scavenging assays, respectively. Moreover, chia seed peptides showed enhanced AChE inhibitory activity with an IC50 value of 14.48 ± 0.88 μg/mL and BChE inhibition activity with an IC50 value of 10.90 ± 0.80 μg/mL. Our results indicate that the newly isolated B. altitudinis 5-DSW and chia seed protein hydrolysates have potential applications in biotechnology and functional food development, enhancing the nutritional quality and value-added utilization of chia byproducts.

Биологически активные гидролизаты белков молока и их комплексы включения с циклодектринами

Enzymatic hydrolysis of dairy proteins increases their nutritional and biological value while reducing their allergenic potential. The subsequent complexation of peptides with cyclodextrins (CDs) reduces the bitterness of the hydrolyzed proteins. The research objective was to obtain hydrolysates of whey proteins and their cyclodextrin inclusion complexes with peptides, as well as to describe the peptide composition of the cleaved dairy proteins, biological activity, and sensory profile of the hydrolysates and inclusion complexes. The research featured enzymatic whey protein hydrolysates with an extensive hydrolysis degree and their inclusion complexes with β- and γ-CDs. Dairy proteins were hydrolyzed with alcalase, and the hydrolysates obtained were subjected to micro- and ultrafiltration (cut-off limit – 10 kDa). The peptide composition of the hydrolyzed proteins was determined by the methods of high-performance liquid chromatography and chromatography-mass spectrometry. The antimutagenic activity was evaluated using the Ames test whereas the antibacterial effect was studied with the impedimetric method. The antioxidant activity was detected with fluorimetry and spectrophotometry. The method of competitive enzyme immunoassay was applied to reveal the antigenic properties. The bitterness of the experimental sample s was determined by a sensory evaluation. The research delivered the optimal modes for whey protein cleavage with alcalase that made it possible to achieve efficient micro- and ultrafiltration. The resulting hypoallergenic peptide fractions and their inclusion complexes with β- and γ-CDs possessed antioxidant, antibacterial, and antimutagenic properties. The whey proteolysis and subsequent filtration with/without tindalization demonstrated a 265/589-fold decrease in the residual antigenicity. The fluorimetric method showed a 1.79/1.90-fold increase in the antioxidant activity of the hydrolysate in complexes with β- and γ-CDs. Binding of β-CDs to peptides enhanced their antimicrobial activity against Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538. The hydrolysate samples with β-CDs showed less bitterness. Whey proteolysis with alcalase under optimized conditions and subsequent fractionation resulted in a product with high consumer qualities. Enzymatic hydrolysates of dairy proteins and their CD inclusion complexes were able to substitute native protein components. Their bioactive properties, good taste, and low allergenic potential mean good prospects for the functional food industry.

Effect of acid and fermented silage hydrolysis time on protein fractionation and digestibility for Nile Tilapia

World aquaculture production currently demands sustainable protein ingredients that can compete with fishmeal regarding nutritional quality and economic feasibility. In this study, the protein fractionation of silages prepared with Nile tilapia processing waste (heads, spine, fins, and viscera) by two processes and three hydrolysis times was evaluated, considering the digestibility coefficients of its crude protein, amino acids, and gross energy of Nile tilapia juveniles. The apparent digestibility coefficients (ADCs) were determined using 360 Nile tilapia juveniles (9.36 ± 0.74 g) distributed in 18 tanks (150 L), following a completely randomized design with six treatments, in a factorial scheme of 2×3, with three replicates. The six test diets were composed of 69.5 % of the reference diet, 0.5 % chromium (III) oxide, and 30 % of either acid or fermented silages produced with three hydrolysis times (24, 96, and 192 hours). The results demonstrated that both the processing type and hydrolysis time influenced the profile and peptide fractions of the silages. The acid silage was faster in relation to the release of free α-amino groups and the degree of hydrolysis (DH), up to 192 hours of hydrolysis. After this period, the fermented silage showed a higher degree and speed of hydrolysis. SDS-PAGE demonstrated that a longer hydrolysis time increased the concentration of the protein band between 150 and 100 kDa, indicating a proliferation of microorganisms using the free amino acids produced during fermentation. Regarding the distribution of peptides, acid silage presented higher values for the concentration of polypeptides, slow degradation and proportion among fractions, with the appearance of di- and tripeptides, as well as free amino acids. For the fermented silage, a higher degradation of polypeptides into oligopeptides was verified, representing the highest fraction, with a small proportion of di- and tripeptides and free amino acids. ADC values were high for all amino acids and proteins, which was not observed for the mean values of energy ADC. The production of silages with 192 hours of hydrolysis proved to be viable, and the fermented processing revealed the highest ADC values in relation to most of the amino acids, thus being the most indicated to be incorporated in fish diets, favoring its utilization by small farmers and reducing the inadequate disposal of biodegradable waste, thereby avoiding environmental pollution.

Antioxidant potential and stability of bovine liver peptides in fermented sausage (sucuk): A pathway to value-added functional meat products

The objective of the present study was to evaluate the stability of low-molecular-weight peptides after their incorporation into fermented sausages. Peptide fractions were produced from the bovine liver peptides (BLP) by enzymatic hydrolysis. Optimal conditions were identified as hydrolysis at 45 °C for 24 h, resulting in the generation of <3 kDa and <10 kDa peptide fractions exhibiting the highest antioxidant activity. The antioxidant potential of fermented sausages made from beef meat containing BLPs at 0.5% and 1% concentrations was assessed during manufacturing and storage. The initial antioxidant activity values of the sausages containing BLPs were higher than that of the control. Furthermore, the stability of the peptides in the sausages was demonstrated by their preserved antioxidant activity for 102 days. Peptides extracted from 1% of <10 kDa-peptide containing sausages possessed two-fold higher radical scavenging activity than control. The highest peptide concentration in the sausages containing 1% of <10 kDa-peptides (79.32±1.34–101.56±1.22 μg peptide/mg) was maintained from day 0 to day 102. The SDS-PAGE profile of myofibrillar proteins and peptide extracts revealed the degradation of proteins were delayed in <10 kDa of peptide added sausages, suggesting that the protein oxidation was slowed down. These results contribute to the advancement of peptide commercialization as functional ingredients in fermented food products. Furthermore, our research sheds light on the enduring impact of fermentation on the stability of the added peptides and the synergistic interactions between naturally produced peptides during fermentation and those introduced externally.

Study of the in vitro digestibility of oilseed protein concentrates compared to isolates for food applications

The research has primarily focused on isolates (>90 % protein) when studying oilseed protein products, but there is a growing interest in concentrates (65–90 % protein) due to their industrial viability and lower environmental impact. This study aimed to compare the in vitro digestibility of rapeseed and sunflower protein concentrates with isolates. Simulated digestion was conducted, and the resulting samples were analyzed using a size-exclusion chromatography approach. This approach can reliably quantify assimilable peptide fractions without interference from the complex matrix of these products. Surprisingly, similar digestibility values (around 40 %) were found for both oilseed protein concentrates and isolates. The study also compared the digestibility of total protein isolates versus albumin isolates from rapeseed and sunflower. The results highlighted the significant gastrointestinal resistance of the albumin fraction, which is the most important factor affecting the digestibility of these products. These digestibility results emphasize the strong potential of concentrates in food applications.

Precooked Jack Bean [Canavalia ensiformis (L.) DC] Sprout: Generation of Dipeptidyl Peptidase-IV Inhibitory Peptides during Simulated Digestion.

Bioactive peptides generated from jack bean sprouts are reported to function as dipeptidyl peptidase IV (DPP-IV) inhibitors. However, no studies have investigated the effect of precooking followed by simulated digestion using pepsin-pancreatin to increase DPP-IV inhibitory peptide generation in jack bean sprouts. Therefore, the present study aimed to explore the generation of DPP-IV inhibitory peptides from precooked jack bean [Canavalia ensiformis (L.) DC] sprouts during simulated digestion with pepsin-pancreatin. The results showed that peptide fractions of the sample hydrolysate with molecular weight <1 kDa exhibited the strongest DPP-IV inhibitory activity (84.77%±0.49%) after simulated digestion. This activity was slightly greater than that (74.12%±0.85%) observed prior to simulated digestion. These findings demonstrate that the DPP-IV inhibitory activity of precooked jack bean sprouts can be retained following simulated digestion. Moreover, our investigation revealed the sequences of two novel peptides following simulated digestion with critical amino acids. The presence of alanine and glycine at the penultimate N-terminus of AAGPKP and LGDLLK confirmed the presence of DPP-IV inhibitors. Both peptide sequences are nontoxic and interact with the catalytic sites of enzymes through hydrogen bonds.

Biochemical composition of biological substances extracted from red deer antlers

We aim to study biologically active agents in biological substances obtained from different parts of red deer antlers. Frozen red deer antlers were separated into skin and antler base, crushed, and subjected to ultrasonic enzymatic hydrolysis. The press cake from the extraction of antler base was dried in a vacuum unit. The content of protein, fat, ash, and moisture in the obtained biological substances was studied. In addition, the amino acid, fatty acid, and mineral compositions were analyzed, as well as the molecular weight distribution of peptide fractions. The concentrates from the skin and base of red deer antlers were found to contain the maximum of proteins (73.68–74.41%). The mineral biological substances comprise the maximum of macroand microelements (84.17%), in particular, a high level of 136,000 mg /kg of phosphorus, 29,230 mg /kg of sodium, and 5,140 mg /kg of calcium. All biological substances are characterized by a low-fat content in the range from 0.3 to 1.76%. Similar to the protein content, the total amount of amino acids prevails in concentrates from the skin and base of red deer antlers, equaling 40.90 and 43.66 g /100 g, respectively. Moreover, in both samples, the amount of essential amino acids is higher than that of non-essential ones. The amount of vitamins is low, being represented by B1, B2, B6 water-soluble vitamins. The fatty acid composition is most balanced in the concentrate from the red deer antler base, containing omega-3 and omega-6. The ratio of unsaturated to saturated fatty acids is equal to 0.96. In the concentrate from antler skin, the maximum content (54.7%) of peptides with a low molecular weight of less than 2.9 kDa and up to 6.4 kDa was found using the molecular-weight distribution of peptide fractions.