Characterization and production of novel antioxidative peptides derived from fermented goat milk by L. fermentum

Analytical approaches for assessing protein structure in protein-rich food: A comprehensive review

This review focuses on changes in nutrition and functional properties of protein-rich foods, primarily attributed to alterations in protein structures. We provide a comprehensive overview and comparison of commonly used laboratory methods for protein structure identification, aiming to offer readers a convenient understanding of these techniques. The review covers a range of detection technologies employed in food protein analysis and conducts an extensive comparison to identify the most suitable method for various proteins. While these techniques offer distinct advantages for protein structure determination, the inherent complexity of food matrices presents ongoing challenges. Further research is necessary to develop and enhance more robust detection methods to improve accuracy in protein conformation and structure analysis.

Production and characterization of anti-hypertensive and anti-diabetic peptides from fermented sheep milk with anti-inflammatory activity: in vitro and molecular docking studies

BACKGROUND

The present study aimed to evaluate the anti-hypertensive and anti-diabetic activities from biologically active peptides produced by fermented sheep milk with Lacticaseibacillus paracasei M11 (MG027695), as well as to purify and characterize the angiotensin-converting enzyme (ACE) inhibitory and anti-diabetic peptides produced from fermented sheep milk.

RESULTS

After 48 h of fermentation at 37 °C, sheep milk demonstrated significant changes in anti-diabetic effects and ACE-I effects, with inhibition percentages observed for ACE inhibition (76.32%), α-amylase (70.13%), α-glucosidase (70.11%) and lipase inhibition (68.22%). The highest level of peptides (9.77 mg mL-1) was produced by optimizing the growth conditions, which included an inoculation rate of 2.5% and a 48 h of incubation period. The comparison of molecular weight distributions among protein fractions was conducted through sodium dodecyl-sulfate polyacrylamide gel electrophoresis analysis, whereas spots were separated using 2D gel electrophoresis according to both the molecular weight and pH. Peptide characterization with ultra-filtration membranes at 3 and 10 kDa allowed the study to assess molecular weight-based separation. Nitric oxide generated by lipopolysaccharide and the secretion of pro-inflammatory cytokines in RAW 264.7 immune cells were both inhibited by sheep milk fermented with M11. Fourier-transform infrared spectroscopy was employed to assess changes in functional groups after fermentation, providing insights into the structural changes occurring during fermentation.

CONCLUSION

The present study demonstrates that fermentation with L. paracasei (M11) led to significant changes in fermented sheep milk, enhancing its bioactive properties, notably in terms of ACE inhibition and anti-diabetic activities, and the generation of peptides with bioactive properties has potential health benefits. © 2024 Society of Chemical Industry.

Peptidomics-based identification of antihypertensive and antidiabetic peptides from sheep milk fermented using Limosilactobacillus fermentum KGL4 MTCC 25515 with anti-inflammatory activity: in silico, in vitro, and molecular docking studies

This study investigated the synthesis of bioactive peptides from sheep milk through fermentation with Limosilactobacillus fermentum KGL4 MTCC 25515 strain and assessed lipase inhibition, ACE inhibition, α-glucosidase inhibition, and α-amylase inhibition activities during the fermentation process. The study observed the highest activities, reaching 74.82%, 70.02%, 72.19%, and 67.08% (lipase inhibition, ACE inhibition, α-glucosidase inhibition, and α-amylase inhibition) after 48 h at 37°C, respectively. Growth optimization experiments revealed that a 2.5% inoculation rate after 48 h of fermentation time resulted in the highest proteolytic activity at 9.88 mg/mL. Additionally, fractions with less than 3 kDa of molecular weight exhibited superior ACE-inhibition and anti-diabetic activities compared to other fractions. Fermentation of sheep milk with KGL4 led to a significant reduction in the excessive production of NO, TNF-α, IL-6, and IL-1β produced in RAW 267.4 cells upon treatment with LPS. Peptides were purified utilizing SDS-PAGE and electrophoresis on 2D gels, identifying a maximum number of proteins bands ranging 10-70 kDa. Peptide sequences were cross-referenced with AHTPDB and BIOPEP databases, confirming potential antihypertensive and antidiabetic properties. Notably, the peptide (GPFPILV) exhibited the highest HPEPDOCK score against both α-amylase and ACE.

Shotgun proteomics and molecular simulations on multifunctional bioactive peptides derived from the whey of unexplored "Gaddi" goat of Himalayas

The very first time, whey protein from the Himalayan goat breed "Gaddi" was hydrolyzed with alcalase, flavourzyme, and a combination of both in this study. The degree of hydrolysis (DH) ranged from 28 to 53%, with sequential hydrolysis by combination achieving the highest DH. The sequential hydrolysis demonstrated antimicrobial activity against all pathogens used with 3 kDa permeate showed significantly higher (p < 0.05) activity against S. aureus, E. coli, B. cereus and C. sakazakii. The antioxidant activity was in the range of IC50 = 0.49 to 2.00 mg protein/mL, flavourzyme and sequential hydrolysates showed significant ABTS radical and FRAP inhibition. The α-amylase inhibitory activity was highest in 3 kDa permeate of flavourzyme with IC50 values of 0.34 mg protein/mL. Bioactive peptides DDSPDLPK, EMPFPK and TPEVDKEALEK were identified most significant in the hydrolysates. In molecular docking, the DDSPDLPK interacted most efficiently with enzymes involved in microbial growth, oxidative stress, and hyperglycemia.

Brassica-derived isothiocyanates as anticancer therapeutic agents and their nanodelivery

The isothiocyanates (ITCs) derived from the precursor glucosinolate molecules present in Brassica vegetables are bioactive organo-sulfur compounds with numerous pharmacologically important properties such as antioxidant, antiinflammatory, antimicrobial, and anticancer. Over the years, ITCs have been the focus of several research investigations associated with cancer treatment. Due to their potent chemo-preventive action, ITCs have been considered to be promising therapeutics for cancer therapy in place of the already existing conventional anticancer drugs. However, their wide spread use at the clinical stage is greatly restricted due to several factors such as low solubility in an aqueous medium, low bioavailability, low stability, and hormetic effect. To overcome these hindrances, nanotechnology can be exploited to develop nano-scale delivery systems that have the potential to enhance stability, and bioavailability and minimize the hermetic effect of ITCs.

Chicken viscera meal as substrate for the simultaneous production of antioxidant compounds and proteases by Aspergillus oryzae

The use of chicken waste can contribute to the development of new processes and obtaining molecules with high added value. An experimental design was applied to evaluate the effect of moisture, temperature, and inoculum size on the production of antioxidant peptides and proteases by A. oryzae IOC3999 through solid-state fermentation (SSF) of chicken viscera meal. As a result, the process conditions strongly influenced protease production and antioxidant activity of the fermented products. A global analysis of the results indicated that the most adequate conditions for SSF were (assay 9): 40% initial moisture, 30 °C as the incubation temperature, 5.05 × 106 spores/g as the inoculum size, and 48-h fermentation as the fermentation time. Under this condition, the antioxidant activities for the ABTS- and DPPH-radicals inhibition and ferric reducing antioxidant power (FRAP) methods were 376.16, 153.29, and 300.47 (µmol TE/g), respectively, and the protease production reached 428.22 U/g. Ultrafiltration of the crude extract obtained under optimized fermentation conditions was performed, and the fraction containing peptides with molecular mass lower than 3 kDa showed the highest antioxidant activity. The proteases were biochemically characterized and showed maximal activity at pH values ranging from 5.0 to 6.0 and a temperature of 50 °C. The thermodynamic parameters indicated that the process of thermal protease inactivation is not spontaneous (ΔG*d > 88.78 kJ/mol), increasing with temperature (ΔH*d 27.01-26.88 kJ/mol), and with reduced disorder in the system (ΔS*d <  - 197.74 kJ/mol) probably caused by agglomeration of partially denatured enzymes.

"In vitro antimicrobial and synergistic effect of fermented Indian zebu (Sahiwal) cow colostrum whey derived peptides with Lactobacillus rhamnosus against pathogenic bacteria"

Bioactive peptides (BAPs) have been found to promote health through various mechanisms. Among them, antimicrobial peptides are gaining recognition as promising novel treatments. This study aims to generate BAPs from bovine colostrum whey using the proteolytic activity of Lactobacillus rhamnosus C25 and to evaluate their potential antibacterial efficacy, including their ability to synergistic efficacy against resistant bacteria. Bioactive peptides were successfully generated from lactobacillus culture proteases that were cultivated through batch fermentation. The resulting peptide fractions were then evaluated for their antibacterial efficacy against a selection of strains, including E. coli ATCC25922, S. aureus MTCC1144, Acinetobacter baumannii ATCC 17978, as well as clinically isolated resistant strains of E. coli (ESBL 1384), Acinetobacter 1379, and S. aureus (MRSA 1418). Notably, the peptide fractions with a molecular weight of < 10 kDa (0-10 kDa) significantly increased the membrane permeability of both E. coli (70.30 ± 0.41%) and S. aureus (63.04 ± 0.31%) as assessed by the crystal violet assay. The checkerboard method was utilized to perform synergistic tests with peptides and antibiotics. The peptide fractions with a molecular weight of (< 10 kDa) demonstrated synergistic effects with several antibiotics, including gentamycin, Rifampicin, Levofloxacin, Ciprofloxacin, and Chloramphenicol, against the resistant ESBL 1384 strain, as indicated by ΣFICI values of 0.55, 0.53, 0.52, 0.54, and 0.52, respectively. Furthermore, the HT-29 cell line remained completely unaffected by both peptide fractions. These findings suggest that the < 10 kDa peptide fraction possesses significant antibacterial efficacy against both reference and ESBL 1384 resistant bacterial strain. Additionally, both MRSA 1418 and Acinetobacter 1379 displayed resistance to all fractions tested. To summarize the findings of this study, colostrum whey peptides with a broad spectrum of antimicrobial activity can be efficiently produced through fermentation. This method could prove valuable for both the pharmaceutical and food industries.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05776-2.

Exploring the health benefits and functional properties of goat milk proteins

Goat milk proteins are unique in their nutritional and functional properties and have become increasingly popular in recent years. A variety of methods have been studied for extracting and isolating these proteins, with coprecipitation being a particularly effective approach. Compared to cow milk proteins, goat milk proteins contain higher levels of certain amino acids such as tryptophan and cysteine, while maintaining similar nutritional properties. Additionally, they have superior functional properties, including better emulsifying and foaming properties, which make them an attractive option for developing new food products. Research has shown that goat milk proteins have several health benefits, including immunomodulatory effects, allergy management, anti-inflammatory, and antioxidant effects, as well as antimicrobial and anticancer properties. They have the potential to be used as a treatment for autoimmune diseases, allergies, and other immune system disorders due to their ability to modulate the production of cytokines and other immune system components. Furthermore, their antimicrobial properties can help prevent the growth of harmful bacteria and reduce the risk of infection. Future research will focus on the potential of goat milk proteins as a functional food ingredient, their effects on gut health and microbiota, and their therapeutic potential for various health conditions. This research may lead to the development of new functional foods that promote health and prevent disease, and potentially pave the way for the use of goat milk proteins as a therapeutic agent for various health conditions.

Production and Characterization of ACE Inhibitory and Anti-Diabetic Peptides from Buffalo and Camel Milk Fermented with Lactobacillus and Yeast: A Comparative Analysis with In Vitro, In Silico, and Molecular Interaction Study

The investigation aimed at assessing a comparative study on the production and characterization of ACE inhibitory, anti-diabetic, and anti-inflammatory activities, along with the production of ACE inhibitory and anti-diabetic peptides through the fermentation of buffalo and camel milk by Limosilactobacillus fermentum (KGL4) and Saccharomyces cerevisiae (WBS2A). The angiotensin-converting enzyme (ACE) inhibitory and anti-diabetic properties were evaluated at particular time intervals (12, 24, 36, and 48 h) at 37 °C, and we discovered maximum activity at 37 °C after 48 h of incubation. The maximum ACE inhibitory, lipase inhibitory activities, alpha-glucosidase inhibitory, and alpha-amylase inhibitory activities were found in the fermented camel milk (77.96 ± 2.61, 73.85 ± 1.19, 85.37 ± 2.15, and 70.86 ± 1.02), as compared to the fermented buffalo milk (FBM) (75.25 ± 1.72, 61.79 ± 2.14, 80.09 ± 0.51, and 67.29 ± 1.75). Proteolytic activity was measured with different inoculation rates (1.5%, 2.0%, and 2.5%) and incubation times (12, 24, 36, and 48 h) to optimize the growth conditions. Maximum proteolysis was found at a 2.5% inoculation rate and at a 48 h incubation period in both fermented buffalo (9.14 ± 0.06) and camel milk (9.10 ± 0.17). SDS-PAGE and 2D gel electrophoresis were conducted for protein purification. The camel and buffalo milk that had not been fermented revealed protein bands ranging from 10 to 100 kDa and 10 to 75 kDa, respectively, whereas all the fermented samples showed bands ranging from 10 to 75 kDa. There were no visible protein bands in the permeates on SDS-PAGE. When fermented buffalo and camel milk were electrophoresed in 2D gel, 15 and 20 protein spots were detected, respectively. The protein spots in the 2D gel electrophoresis ranged in size from 20 to 75 kDa. To distinguish between different peptide fractions, water-soluble extract (WSE) fractions of ultrafiltration (3 and 10 kDa retentate and permeate) of fermented camel and buffalo milk were employed in RP-HPLC (reversed-phase high-performance liquid chromatography). The impact of fermented buffalo and camel milk on inflammation induced by LPS (lipopolysaccharide) was also investigated in the RAW 264.7 cell line. Novel peptide sequences with ACE inhibitory and anti-diabetic properties were also analyzed on the anti-hypertensive database (AHTDB) and bioactive peptide (BIOPEP) database. We found the sequences SCQAQPTTMTR, EMPFPK, TTMPLW, HPHPHLSFMAIPPK, FFNDKIAK, ALPMHIR, IPAVFK, LDQWLCEK, and AVPYPQR from the fermented buffalo milk and the sequences TDVMPQWW, EKTFLLYSCPHR, SSHPYLEQLY, IDSGLYLGSNYITAIR, and FDEFLSQSCAPGSDPR from the fermented camel milk.

Anti-Inflammatory, ACE Inhibitory, Antioxidative Activities and Release of Novel Antihypertensive and Antioxidative Peptides from Whey Protein Hydrolysate with Molecular Interactions

OBJECTIVE

The aim of the study was to evaluate the whey protein hydrolysate with bio-functional attributes viz. antioxidative, anti-inflammatory and ACE inhibition efficacy and release of bioactive peptides with antioxidative and ACE-inhibitory activity by employing Pepsin.

METHOD

The antioxidant, Anti-inflammatory, ACE inhibitory and proteolytic activities of the whey protein hydrolysates were studied followed by SDS-PAGE analysis and IEF. Anti-inflammatory activity of whey protein hydrolysate was also studied on RAW 264.7 cell line. The separation of the bioactive peptides from whey protein hydrolysate was achieved by RP-HPLC. The purified bioactive peptides were identified and characterized using RPLC/MS.

RESULTS

WPC (Whey protein concentrate) hydrolysate with pepsin showed proteolytic activity ranging between 14.46 and 18.87 mg/ml. Using the ABTS assay, the highest antioxidative activity was observed in 10 kDa retentate (84.50%) and 3 kDa retentate (85.96%), followed by the highest proteolytic activity (13.83 mg/ml) and ACE inhibitory activity (58.37%) in a 5% WPC solution at 65 °C after 8 h of pepsin hydrolysis. When the protein hydrolysate concentration was low, the production of proinflammatory cytokines by lipopolysaccharide-treated murine macrophages (RAW 264.7) was reduced. SDS-PAGE results exhibited very little protein bands when comparing with WPC hydrolysates to insoluble WPC. There were no protein spots on 2 D gel electrophoresis and "in-solution trypsin digestion" technique have been utilized to digest protein samples directly from WPC hydrolysates. Novel antioxidative peptides and ACE inhibitory peptides were also observed by comparing two databases, i.e., BIOPEP and AHTPDB respectively. The peptide sequences used in this study were found to have excellent potential to be used as inhibitors of hACE as all of them were able to show substantial interactions against the enzyme's active site.

CONCLUSIONS

The antihypertensive and antioxidative peptides from whey protein hydrolysates may be beneficial for the future development of physiologically active functional foods. Further, in vivo investigations are required to establish the health claim for each individual bioactive peptide from whey protein hydrolysate.

Supplemental data for this article is available online at.

Significance of Lactobacillus fermentum on Antioxidative and Anti-Inflammatory Activities and Ultrafiltration Peptide Fractions as Potential Sources of Antioxidative Peptides from Fermented Camel Milk (Indian Breed)

OBJECTIVE

The present study aimed to assess the bio-functional analysis of camel milk viz. anti-oxidative, anti-inflammatory activities using potent Lactobacillus fermentum (KGL4) strain through fermentation and also to release the bioactive peptides during fermentation.

METHOD

The antioxidant and proteolytic activities of the fermented camel milk were studied followed by SDS-PAGE analysis and 2 D PAGE. The separations of the bioactive peptides of water-soluble extract (WSE) of 3 and 10 kDa (Permeates & Retentates) were achieved by RP-HPLC. The purified bioactive peptides were identified and characterized using RPLC/MS and the effect of WSE of camel milk fermented with KGL4 on lipopolysaccharide (LPS)/endotoxin-induced inflammation in RAW 264.7 macrophages were also studied.

RESULTS

The maximal activity was observed in ABTS assay (64.03%), then in hydroxyl free radical scavenging assay, and minimal activity was observed in superoxide free radical assay (57.75%). ABTS assay was significantly (P < 0.05) higher than other assays. MTT assay was performed on WSE of camel milk fermented with KGL4 using treated macrophage cells with different concentrations and found the decreasing range of cell viability at 0.25 mg/mL treatment which was non-significant. 7.80 mg/ml peptide production was found after 48 h of fermentation using the OPA method. Further, WSE of fermented camel milk was separated and analyzed their protein profiles using SDS-PAGE and 2 D-PAGE techniques. Here, many new peptides were found in camel milk when fermented with KGL4 strain. Each protein sequence was characterized through bioinformatic tools, including SWISS-PROT & PIR protein databases. Novel bioactive anti-oxidative peptides were found by searching in the BIOPEP database.

CONCLUSIONS

The present study suggests that the L. fermentum KGL4 strain could be explored to produce novel antioxidative peptides from fermented camel milk (Indian breed).

Exploring the potential of Lacticaseibacillus paracasei M11 on antidiabetic, anti-inflammatory, and ACE inhibitory effects of fermented dromedary camel milk (Camelus dromedaries) and the release of antidiabetic and anti-hypertensive peptides

The goal of this investigation was to find antidiabetic peptides and inhibit angiotensin converting enzyme (ACE) in Lacticaseibacillus paracasei (M11) fermented dromedary camel milk (Camelus dromedaries). According to the findings, the rate of antidiabetic activity increased along with the incubation periods and reached its peak after 48 hr of fermentation. The inhibitions of α-amylase, α-glucosidase, and lipase were 80.75, 59.62, and 65.46%, respectively. The inhibitory activity of ACE was 78.33%, and the proteolytic activity was 8.90 mg/mL. M11 at 0.25 mg/mL effectively suppressed LPS-induced pro-inflammatory cytokines and their mediators such as NO, TNF-α, IL-6, and IL-1β in RAW 264.7 cells. The rate of inoculum in the optimization phase was 1.5-2.5%, and the greatest proteolytic activity was observed after 48 hr of fermentation. The investigation of the above property in the ultrafiltered fermented milk exhibited the highest antidiabetic and ACE inhibition activities in the 3 kDa than 10 kDa fractions. The molecular weight was determined employing SDS-PAGE, and the six-peptide sequences were identified using 2D gel electrophoresis. Due to its high proteolytic activity, the L. paracasei strain has been reported to be useful in the production of ACE-inhibitory and antidiabetic peptides. Amino acid sequences such from ɑ1, ɑ2, and β-caseins have been identified within fermented camel milk by searching on online databases, including BIOPEP (for antidiabetic peptides) and AHTPDB (for hypertension peptides) to validate the antidiabetic and ACE-inhibitory actions of several peptides. PRACTICAL APPLICATIONS: The study aims to identify antidiabetic peptides and inhibit ACE in dromedary camel milk fermented with Lacticaseibacillus paracasei M11. Maximum antidiabetic and ACE-inhibitory actions of the fermented camel milk were observed in 3 kDa permeate fractions. Fermented camel milk significantly reduced the excessive TNF-α, IL-6, and IL-1β production in LPS-activated RAW 264.7 cells. RP-LC/MS was used to identify 6 bioactive peptides from dromedary fermented camel milk. This fermented camel milk could be used for the management of hypertension and diabetic related problems.

Peptidomics-based identification of an antimicrobial peptide derived from goat milk fermented by Lactobacillus rhamnosus (C25)

Antimicrobial peptides (AMPs) are emerging as promising novel drug applicants. In the present study, goat milk was fermented using Lactobacillus rhamnosus C25 to generate bioactive peptides (BAPs). The peptide fractions generated were separated using ultrafiltration membranes with molecular weight cut-offs of 3, 5, and 10 kDa, and their antimicrobial activity toward Gram-positive and Gram-negative bacteria was investigated. Isolated AMPs were characterized using RP-HPLC and identified by LC-MS/MS. A total of 569 sequences of peptides were identified by mass spectrometry. Out of the 569, 36 were predicted as AMPs, 21 were predicted as cationic, and out of 21, 6 AMPs were helical peptides. In silico analysis indicated that the majority of peptides were antimicrobial and cationic in nature, an important factor for peptide interaction with the negative charge membrane of bacteria. The results showed that the peptides of <5 kDa exhibited maximum antibacterial activity against E. faecalis, E. coli, and S. typhi. Further, molecular docking was used to evaluate the potent MurD ligase inhibitors. On the basis of ligand binding energy, six predicted AMPs were selected and then analyzed by AutoDock tools. Among the six AMPs, peptides IGHFKLIFSLLRV (-7.5 kcal/mol) and KSFCPAPVAPPPPT (-7.6 kcal/mol), were predicted as a high-potent antimicrobial. Based on these findings, in silico investigations reveal that proteins of goat milk are a potential source of AMPs. This is for the first time that the antimicrobial peptides produced by Lactobacillus rhamnosus (C25) fermentation of goat milk have been identified via LC-MS/MS and predicted as AMPs, cationic charges, helical structure in nature, and potent MurD ligase inhibitors. These peptides can be synthesized and improved for use as antimicrobial agents. PRACTICAL APPLICATIONS: Goat milk is considered a high-quality source of milk protein. According to this study, goat milk protein is a potential source of AMPs, Fermentation can yield goat milk-derived peptides with a broad antibacterial activity spectrum at a low cost. The approach described here could be beneficial in that the significant AMPs can be synthesized and used in the pharmaceutical and food industries.

Purification and Characterization of Novel Antihypertensive and Antioxidative Peptides From Whey Protein Fermentate: In Vitro, In Silico, and Molecular Interactions Studies

OBJECTIVE

The goal of this research was to purify and characterize the novel angiotensin-converting enzyme (ACE)-inhibitory and antioxidant peptides from fermented whey protein concentrate produced by Lactobacillus paracasei and Saccharomyces cerevisiae in a co-fermentation system.

METHOD

Whey protein fermented with lactic acid bacteria and yeast culture was analyzed for antioxidative, ACE inhibition, as well as anti-inflammatory activity followed by SDS-PAGE, isoelectric focusing, and 2-dimensional (2D) analysis. Anti-inflammatory activity of whey protein fermentate was also studied on the RAW 264.7 cell line. The bioactive peptides were separated from the whey protein fermentate using reverse-phase high-performance liquid chromatography (RP-HPLC) and reverse-phase liquid chromatography mass spectrometry (RPLC/MS), and thus identification and characterization of purified bioactive peptide was performed.

RESULTS

Whey protein fermentate samples' bioactivity was analyzed at specific time intervals at 12, 24, 36, and 48 hours at 37 °C for M11 and at 25 °C for WBS2A. The development settings (incubation time [12, 24, 36, and 48 hours) and inoculation rates [1.5%, 2.0%, and 2.5%]) were optimized for peptide synthesis via the o-phthaldialdehyde (OPA) method (proteolytic activity). Maximum proteolytic activity was observed at 37 °C for M11 (6.50 mg/mL) and at 25 °C for WBS2A (8.59 mg/mL) for 48 hours of incubation. Protein profiling was carried out using SDS-PAGE and 2D gel electrophoresis, in which Sodium dodecyl-sulfate (SDS) exhibited protein bands in the 10- to 55-kDa range, while 2D showed protein bands varying from 10 to 70 kDa. Every spot from 2D was digested by trypsin and identified by RPLC/MS. Protein fractionations (3- and 10-kDa permeates) were carried out employing RP-HPLC. Whey protein fermentate has anti-inflammatory action in RAW 264.7 macrophages that have been exposed to lipopolysaccharide. A molecular docking system was also used to investigate the interactions of peptides (AFLDSRTR, ILGAFIQIITFR) with human myeloperoxidase enzyme.

CONCLUSIONS

The antihypertensive and antioxidative peptides discovered from whey protein fermentate may be helpful in the design of pharmacologically active healthy ingredients in the upcoming years.

Purification and characterization of antioxidative and antimicrobial peptides from lactic-fermented sheep milk

This study aims to identify antioxidant and antimicrobial peptides from sheep milk produced using Lactobacillus plantarum (KGL3A). It was inferred that antioxidative and antimicrobial activities increased with increasing incubation time, and antioxidative properties (ABTS assay, superoxide free radical & hydroxyl free radical scavenging activity were 34.5, 34.7, and 29.2% respectively) and antimicrobial properties against Escherichia coli, S. typhimurium, E. faecalis, & B. cereus were 11.3, 12.7, 13.3, & 12.3 mm. However, inoculation of culture at a level of 2.5% and 48 h fermentation give the highest proteolysis activities. Fermented sheep milk fractions of 3 & 10 kDa were analysed for antioxidative and antimicrobial activity, and the 10 kDa permeate showed the highest ABTS assay. The hydroxyl free radical scavenging activity was greatest in 10 kDa retentate and superoxide free radical scavenging activity was observed in 3 kDa permeate (34.7, 43.4, and 34.6%, respectively). Antimicrobial activity of 10 kDa retentate against B. cereus & E. coli (13.3 mm) was greater than 3 and 10 kDa retentate against S. typhimurium (13 mm) and 3 kDa retentate against E. faecalis (13.7 mm). The molecular weight of the protein was estimated using SDS-PAGE. On electrophoresis on a 2-D gel, 6 peptides were identified using RP-LC/MS. BIOPEP, a database for antioxidative and antimicrobial peptides, validated the antioxidative & antimicrobial activities of several peptides in sheep's milk that has been fermented. Sheep milk fermented using Lactobacillus could be considered a novel source of antioxidative and antimicrobial proteins.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05493-2.

Single and Co-Cultures of Proteolytic Lactic Acid Bacteria in the Manufacture of Fermented Milk with High ACE Inhibitory and Antioxidant Activities

In this study, single and co-cultures of proteolytic Lactobacillus delberueckii subsp. bulgaricus ORT2, Limosilactobacillus reuteri SRM2 and Lactococcus lactis subsp. lactis BRM3 isolated from different raw milk samples were applied as starter cultures to manufacture functional fermented milks. Peptide extracts from fermented milk samples were evaluated after fermentation and 7 days of cold storage for proteolytic, angiotensin-converting enzyme (ACE) inhibitory and antioxidant activity by different methods including 2, 2′-diphenyl-1-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP), OH-radical scavenging, and total antioxidant (molybdate-reducing activity). The highest proteolysis was found in milk fermented by co-cultures of three strains. Fermentation with the mentioned bacteria increased ACE inhibitory and antioxidant activity of the final products which were dependent on peptide concentration. The crude peptide extract obtained from fermented milk with triple co-culture showed the highest ACE inhibitory activity (IC50 = 0.61 mg/mL) which was reduced after 7 days of cold storage (IC50 = 0.78 mg/mL). Similar concentration-dependent activities were found in antioxidant activity at different antioxidant assays. Overall, high proteolytic activity resulted in increased ACE inhibitory and antioxidant activities, but the highest activity was not necessarily found for the samples with the highest proteolytic activity. The results of this study suggest the potential of using co-cultures of L. delberueckii subsp. bulgaricus, L. reuteri and L. lactis subsp. Lactis to manufacture antihypertensive fermented milk.

Nutritional Profile, Processing and Potential Products: A Comparative Review of Goat Milk

Goat milk contains an abundance of different macro and micro-nutrients. Compared with other milk, goat milk is a viable option due to its low allergy levels and is preferred for infants with cow milk allergies. A wide variety of goat milk-based products, including yoghurt, ice cream, fermented milk, and cheese, are available on the market. They are produced using effective processing technology and are known to exhibit numerous health benefits after consumption. However, goat milk consumption is limited in many nations (compared with cow, buffalo, camel, and sheep milk) due to a lack of awareness of its nutritional composition and the significance of its different byproducts. This review provides a detailed explanation of the various macronutrients that may be present, with special attention paid to each component, its purpose, and the health benefits it offers. It also compares goat milk with milk from other species in terms of its superiority and nutritional content, as well as the types, production methods, health advantages, and other beneficial properties of the various goat milk products that are currently available on the market.

Significance of whey protein hydrolysate on anti-oxidative, ACE-inhibitory and anti-inflammatory activities and release of peptides with biofunctionality: an in vitro and in silico approach

The study aimed to investigate potent antioxidant activities (ABTS assay, Hydroxyl free radical scavenging assay, and Superoxide free radical assay), ACE inhibitory activity, and anti-inflammatory activity in the WPC (whey protein concentrate) hydrolysate using Alcalase. The hydrolysis conditions (addition rate and incubation times) for peptide synthesis were also optimized using proteolytic activity. The generation of proinflammatory cytokines by lipopolysaccharide-treated murine macrophages was reduced when the protein hydrolysate concentration was low. In comparison to unhydrolyzed WPC, SDS-PAGE examination revealed no protein bands in WPC hydrolysates. Two-Dimensional (2D) gel electrophoresis did not show any protein spots. Using the 'In-solution trypsin digestion' approach, the trypsin digested protein samples were put into RPLC/MS for amino acid sequencing. Peptides were also identified using RPLC/MS on fractions of 3 and 10 kDa permeates and retentates. The MASCOT database was used to look up the raw masses of LC/MS. By comparing hydrolyzed whey protein to the BLASTp (NCBI), PIR, BIOPEP, and AHTPDB databases, novel antioxidative and ACE inhibitory peptides were reported.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05282-3.

Peptidomic profiling of fermented goat milk: considering the fermentation-time dependent proteolysis by Lactobacillus and characterization of novel peptides with Antioxidative activity

In this study, antioxidant activities were evaluated for goat milk fermented with Lactobacillus helveticus MTCC 5463. The fermentation conditions (inoculation rate and incubation time) were optimized by estimating proteolytic action of Lactobacillus. SDS-PAGE and 2D gel electrophoresis were carried out for identification of molecular weight and purification of identified peptides. 3 and 10 kDa peptides fractions were obtained through ultrafiltration and also by using RP-HPLC. Then, spots from 2D and fractions from RP-HPLC were also evaluated in RP-LC/MS for identification and characterization of peptides. Identified peptides were matched with online database of goat milk i.e. BLASTp (NCBI) and Protein information resource database (PIR) and subsequently, antioxidant activity of these peptides were also confirmed with BIOPEP database. However, antioxidative peptides from fermented goat milk with Lactobacillus helveticus MTCC 5463 could be produced in developing functional goat milk yoghurt.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-021-05243-w.

Development of energy-rich protein bars and in vitro determination of angiotensin I-converting enzyme inhibitory antihypertensive activities

Three energy-rich protein (ERP) bars were prepared to meet the daily recommended dietary allowance (RDA) for the protein of Pakistani athletes. The bars were developed using dates, cheddar cheese (CC), whey protein isolate (WPI), roasted chickpea flour, and rice flour in different proportions. Bar #1 contained 64 g dates, 16 g dried apricots, 12 g WPI, and 8 g ripened CC. Bar #2 contained the same proportion of these ingredients with an addition of 12.5 g roasted chickpea flour, while bar #3 contained 6.25 g roasted rice and 6.25 g roasted chickpea flour. All the ingredients were homogeneously mixed into paste to form bars weighing 100-110 g per serving size. These bars were studied for the compositional analysis (moisture, protein, and lipid content), protein characterization through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and in vitro determination of the angiotensin I-converting enzyme (ACE-I) antihypertensive activity. Moisture and lipid content in bars were 22% and 0.057%-0.313%, respectively, while protein, fiber, and ash contents varied from 22.3% to 23.6%, 6.66 to 5.81, and 2.12% to 2.44%, respectively. The minimum energy content was recorded (272.70 Kcal/100 g) in bar #1 while bar #3 showed the highest energy content 274.65 Kcal/110 g with the addition of (5%) roasted chickpea and rice flour, respectively. Electrophoresis analysis of proteins in bar # 1 (cheese +WPI) showed the four bands at 62, 24, 20, and 12 kDa. Bar #2 (10% roasted chickpea flour) showed some additional bands at 40, 36, 34, and 28 kDa while relatively lower antihypertensive activity than bars #1 and 3. The study revealed that adding 10% roasted chickpea flour (bar #2) increased the protein content and diversity in proteins. It provided 40% proteins to athletes and could be helpful to meet their R.D.A. by consuming two bars/day.

Recent Insights Into Processing Approaches and Potential Health Benefits of Goat Milk and Its Products: A Review

Goat milk is considered to be a potential source of various macro- and micro-nutrients. It contains a good proportion of protein, fat, carbohydrates, and other nutritional components which help in promoting nutritional and desirable health benefits. Goat milk is considered to be superior in terms of numerous health benefits, and lower risk of allergy, when compared to the milk of other species. Several processing techniques such as pasteurization, ultrafiltration, microfiltration, and ultrasound have been employed to enhance the quality and shelf life of goat milk and its products. The diverse range of goat milk-based products such as yogurt, cheese, fermented milk, goat milk powder, and others are available in the market and are prepared by the intervention of advanced processing technologies. Goats raised in pasture-based feeding systems are shown to have a better milk nutritional composition than its counterpart. Goat milk contains potential bioactive components, which aids in the maintenance of the proper metabolism and functioning of the human body. This review gives insight into the key nutritional ingredients and bioactive constituents present in goat milk and their potential role in the development of various functional foods using different processing technologies. Goat milk could be considered as a significant option for milk consumption in infants, as compared to other milk available.

Isolation of antioxidant peptides from yak casein hydrolysate

Enzymatic hydrolysis of protein is a principal method to obtain antioxidant peptides. A yak casein hydrolysate (YCH) was prepared by alcalase and trypsin digestion. An ultrafiltration membrane system was used to divide the hydrolysate into four molecular weight fractions; YCH-4 (<3 kDa) had the highest antioxidant activity. Fraction YCH-4 was separated into six subfractions by gel filtration chromatography; reverse-phase high performance liquid chromatography (RP-HPLC) was then used to partition sixteen antioxidant peptide subfractions. Liquid chromatography/electrospray tandem mass spectrometry (LC-ESI-MS/MS) was used to determine the amino acid sequence of a purified antioxidant peptide to be Arg-Glu-Leu-Glu-Glu-Leu (787.41 Da). Finally, a synthetic Arg-Glu-Leu-Glu-Glu-Leu peptide was evaluated for its superoxide anion and hydroxyl radical scavenging activity (IC₅₀ = 0.52 and 0.69 mg mL⁻¹), which confirmed the activity of the native purified peptide. Our results suggested that isolation and purification of antioxidant peptides from yak casein could be an important means to obtain natural antioxidant peptides.

Enzymatic hydrolysis of protein is a principal method to obtain antioxidant peptides.