Lacto-fermented Kenaf (Hibiscus cannabinus L.) seed protein as a source of bioactive peptides and their applications as natural preservatives

Nutritional and potential health benefits of fermented food proteins

BACKGROUND

Protein fermentation continues to gain popularity as a result of several factors, including the cost-effectiveness of the process and the positive correlation of fermented protein consumption, with a reduced risk of developing diet-related diseases such as diabetes and cardiovascular disorders, as well as their enhanced nutritional and techno-functional properties. Nonetheless, the nutritional and health benefits of food protein fermentation such as enhanced nutrient bioavailability, reduced antinutritional factors (ANFs) and enriched bioactive peptides (BAPs) are often overlooked. The present study reviewed recent work on the influence of protein fermentation on nutrition and health. In total, 322 eligible studies were identified on the Scopus and Google Scholar databases out of which 69 studies were evaluated based on our inclusion criteria.

RESULTS

Fermented protein ingredients and products show reduced ANF content, enhanced digestibility and bioavailability, and increased antioxidant and other biological activities, such as probiotic, prebiotic, angiotensin-converting enzyme inhibitory and antihypertensive properties. In addition, co-products in protein fermentation such as BAPs possess and could contribute additional sensory and flavor properties, degrade toxins, and reduce allergens in foods.

CONCLUSION

Thus, fermentation is not only a method for food preservation, but also serves as a means for producing functional food products for consumer health promotion and nutrition enrichment. © 2023 Society of Chemical Industry.

Plant Protein-Derived Active Peptides: A Comprehensive Review

Active peptides are a class of physiologically active protein fragments, which can be prepared from different sources. In the past few decades, the production of peptides with various effects from different plant proteins continues to receive academic attention. With advances in extraction, purification, and characterization techniques, plant protein-derived active peptides continue to be discovered. They have been proven to have various functional activities such as antioxidant, antihypertensive, immunomodulatory, antimicrobial, anti-inflammatory, antidiabetic, antithrombotic, and so on. In this review, we searched Web of Science and China National Knowledge Infrastructure for relevant articles published in recent years. There are 184 articles included in this manuscript. The current status of plant protein-derived active peptides is systematically introduced, including their sources, preparation, purification and identification methods, physiological activities, and applications in the food industry. Special emphasis has been placed on the problems of active peptide exploration and the future trend. Based on these, it is expected to provide theoretical reference for the further exploitation of plant protein-derived active peptides, and promote the healthy and rapid development of active peptide industry.

Anti-Salmonella Activity of a Novel Peptide, KGGDLGLFEPTL, Derived from Egg Yolk Hydrolysate

The present study aimed to characterize the mode of action of a novel antimicrobial peptide isolated from egg yolk hydrolysate. The EYHp6, KGGDLGLFEPTL, exhibited inhibition against Salmonella enterica serovar Typhimurium TISTR 292 and S. enterica serovar Enteritidis DMST 15679 with a MIC value of 2 mM. In contrast, S. enterica serovar Newport ATCC 6962 and other strains of Typhimurium and Enteritidis were inhibited at 4 mM. EYHp6 increased the cell membrane permeability of S. Typhimurium TISTR 292, leading to DNA leakage. Membrane integrity determined by propidium iodide and SYTO9 staining visualized by confocal microscopy demonstrated that EYHp6 at 1 × MIC induced disruption of cell membranes. Electron microscopy revealed that treatment of S. Typhimurium with EYHp6 led to damage to the cell membrane, causing the leakage of intracellular contents. Synchrotron-based Fourier-transform infrared spectroscopy indicated that EYHp6 killed S. Typhimurium by targeting fatty acids and nucleic acids in the cell membrane. The peptide did not show hemolytic activity up to 4 mM. These findings suggest that EYHp6 could be a promising antibacterial agent for controlling the growth of S. enterica.

In vitro antioxidant activity evaluation of pine nut peptides (Pinus koraiensis) fermented by Bacillus subtilis LS-45

In this study, we utilized the remarkable capabilities of Bacillus subtilis ls-45 during the fermentation process to generate pine nut peptide. Through gene sequencing, we confirmed the proficiency of Bacillus subtilis ls-45 in producing protease, thereby serving as a valuable enzymatic source for protein hydrolysis. Our investigation focused on examining the variations in amino acid types and quantities between enzymatic pine nut protein peptide (EPP) and fermented pine nut protein polypeptide (FPP). Furthermore, we conducted a comprehensive assessment of the in vitro antioxidant activities of EPP and FPP, encompassing measurements of their Hydroxyl radical scavenging rate, Total reducing capacity, Superoxide anion scavenging rate, and ABTS+ radical scavenging rate. Notably, FPP exhibited superior antioxidant capacity compared to EPP. By employing semi-inhibitory mass concentration (IC50) analysis, we determined that FPP displayed enhanced efficacy in neutralizing hazardous free radicals when compared to EPP.

Characterization of Physicochemical, Biological, and Chemical Changes Associated with Coconut Milk Fermentation and Correlation Revealed by 1H NMR-Based Metabolomics

Fermentation of milk enhances its nutritional and biological activity through the improvement of the bioavailability of nutrients and the production of bioactive compounds. Coconut milk was fermented with Lactiplantibacillus plantarum ngue16. The aim of this study was to evaluate the effect of fermentation and cold storage for 28 days on physicochemical characteristics, shelf life, and antioxidant and antibacterial activities of coconut milk as well as its proximate and chemical compositions. The pH of fermented milk decreased from 4.26 to 3.92 on the 28^th day during cold storage. The viable cell count of lactic acid bacteria (LAB) in fermented coconut milk was significantly increased during fermentation and cold storage period (1 to 14 days), reaching 6.4 × 10⁸ CFU/mL, and then decreased significantly after 14 days to 1.6 × 10⁸ CFU/mL at 28 days. Yeast and molds in fermented coconut milk were only detected on the 21^st and 28^th days of cold storage, which ranged from 1.7 × 10² to 1.2 × 10⁴ CFU/mL, respectively. However, the growth of coliforms and E. coli was observed on the 14^th until the 28^th day of cold storage. The fermented coconut milk demonstrated strong antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Cronobacter sakazakii, Bacillus cereus, and Salmonella typhimurium compared to fresh coconut milk. Fermented coconut milk had the greatest 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) values, with 67.1% and 61.961 mmol/g at day 14 of cold storage, respectively. Forty metabolites were detected in fermented and pasteurized coconut milk by proton nuclear magnetic resonance (¹H NMR) metabolomics. The principal component analysis (PCA) showed clear difference between the fermented and pasteurized coconut milk as well as the studied cold storage days. The metabolites responsible for this variation were ethanol, valine, GABA, arginine, lactic acid, acetoin, alanine, phenylalanine, acetic acid, methionine, acetone, pyruvate, succinic acid, malic acid, tryptophan, uridine, uracil, and cytosin, which were higher in fermented coconut milk. However, sugars and other identified compounds were higher in fresh coconut milk. The findings of this study show that fermentation of coconut milk with L. plantarum ngue16 had high potential benefits to extending its shelf life and improved biological activities as well as other beneficial nutrients.

A critical review on immunomodulatory peptides from plant sources; action mechanisms and recent advances

Plant protein components contribute positively to human well-being as they modulate the immune status of a consumer, especially when the enzymatic method is employed in order to release their bioactive peptides. These peptides are derived from plant-based foods such as soy, wheat, barley, rye, oats, rice, corn, sorghum, and millet, the famous staple foods around the world. Since these peptides are crucial to functional food among other key industries, the present study endeavored to scout for relevant information within the past three decades, using the Web of Science, Scopus, and Google search engines. In this review, first, the core of immunomodulation and types of immunomodulatory agents will be discussed, followed by the production of plant-based immunomodulatory peptides and their immunomodulatory mechanisms in cells, animals, and humans are also studied. Finally, applications and challenges associated with plant-based immunomodulatory peptides are put forward.

Valorization of green biomass Azolla pinnata fern: multi-parameter evaluation of processing conditions on protein extractability and their influence on the physicochemical, structural, techno-functional properties and protein quality

BACKGROUND

This study determined the effect of processing conditions on protein extractability from Azolla pinnata fern, and their influence on the physicochemical, structural, techno-functional properties and protein quality.

RESULTS

The protein extraction from A. pinnata fern was optimized through response surface methodology obtaining a maximum yield of 18.93% with a recovery rate of 73.66%. The A. pinnata fern protein concentrate (AFPC) had five protein bands with a molecular weight ranging from 17 to 56 kDa. AFPC contained high β-sheet structure (36.61%), favouring its good thermal properties with three endothermic peaks at 54.28, 86.52 and 166.25 °C. The AFPC scored ≥ 1 for all essential amino acids, except for lysine and histidine. The AFPC exhibited exceptionally high techno-functional properties, particularly for water holding (5.46 g g^-1 ) and fat absorption capacity (10.08 g g^-1 ), and gelling properties (5% gelation concentration). The AFPC had high in vitro digestibility of 73%, signifying its high availability for human consumption.

CONCLUSION

The underexploited A. pinnata fern is a potential source of edible protein, thus a promising nutraceutical or ingredient of functional and health-promoting foods. © 2022 Society of Chemical Industry.

Characterization of a Novel Antimicrobial Peptide Isolated from Moringa oleifera Seed Protein Hydrolysates and Its Membrane Damaging Effects on Staphylococcus aureus

The present study sought to identify and characterize a novel antimicrobial peptide, named MOp2 from Moringa oleifera seed protein hydrolysates, and elucidate its potential antimicrobial effects on Staphylococcus aureus. MOp2, with the amino acid sequence of His-Val-Leu-Asp-Thr-Pro-Leu-Leu (HVLDTPLL), was characterized as a hydrophobic anionic AMP of the β-sheet structure. MOp2 exhibited negligible hemolytic activity at 2.0× MIC, suggesting its inhibitory effect on the growth of S. aureus (MIC: 2.204 mM). It maintained more than 90% of antimicrobial activity under 5% salt and about 78% of antimicrobial activity at a high temperature of 115 °C for 30 min. Protease, especially acid protease, reduced its antimicrobial activity to different extents. Moreover, MOp2 caused irreversible membrane damage to S. aureus cells by increasing the membrane permeability, resulting in the release of intracellular nucleotide pools. Additionally, molecular docking revealed that MOp2 could inhibit S. aureus growth by interacting with dihydrofolate reductase and DNA gyrase through hydrogen bonding and hydrophobic interactions. Overall, MOp2 could be a potential novel antimicrobial agent against S. aureus in food processing.

Production of cationic antifungal peptides from kenaf seed protein as natural bio preservatives to prolong the shelf-life of tomato puree

This study determined the favourable fermentation conditions for the production of antifungal peptides from kenaf seeds and their effectiveness in extending the shelf-life of tomato puree. The optimum fermentation conditions for the maximum activity of the antifungal peptides were 8.4% (w/v), 7 days and 3.7% for substrate/water ratio, fermentation time and glucose concentration, respectively. Eight cationic peptides of low molecular weight ranging from 840 to 1876 Da were identified in kenaf seed peptides mixture (KSPM). The minimum inhibitory concentration and minimum fungicidal concentration of KSPM against Fusarium sp. were 0.18 mg/mL and 0.70 mg/mL, respectively, while those for Aspergillus niger were 1.41 mg/mL and 2.81 mg/mL respectively. KSPM exhibited a fungicidal effect and a prolonged lag phase, with increased fungal membrane permeability as the concentration of KSPM increased, as evidenced by the release of intracellular constituents. The treatment of tomato puree with 1000 mg/kg KSPM delayed fungal growth for up to 14 and 23 days at 25 °C and 4 °C respectively, significantly reducing Aspergillus niger and Fusarium sp. counts. In conclusion, kenaf seed peptides prepared by lacto-fermentation possess antifungal activity, hence can be applied as natural bio preservatives to extend the shelf-life of food products such as tomato puree.

Bioactive Peptides: A Promising Alternative to Chemical Preservatives for Food Preservation

Bioactive peptides used for food preservation can prolong the shelf life through bacteriostasis and antioxidation. On the one hand, bioactive peptides can inhibit lipid oxidation by scavenging free radicals, interacting with metal ions, and inhibiting lipid peroxidation. On the other hand, bioactive peptides can fundamentally inhibit the growth and reproduction of microorganisms by destroying their cell membranes or targeting intracellular components. Besides, bioactive peptides are biocompatible and biodegradable in vivo. Therefore, they are regarded as a promising alternative to chemical preservatives. However, bioactive peptides are easily affected by the external environment in practical application, which hinders their commercialization. Currently, the studies to overcome the weakness focus on encapsulation and chemical synthesis. Bioactive peptides have been applied to the preservation of various foods in experimental research, with good results. In the future, with the deepening understanding of their safety and structure-activity relationship, there may be more bioactive peptides as food preservatives.

Biologia futura: medicinal plants-derived bioactive peptides in functional perspective-a review

Bioactive peptides (BPs) are 3-20 amino acid residues, with a molecular weight lower than 6 kDa; originated from the breakdown of proteins by endogenous and exogenous peptidases. While intact in protein these peptides do not exert any biological activity, but as they release from their parent protein, they exert various pharmacological activities such as antidiabetic, antihypertensive, anticancerous, anti-inflammatory, antimicrobial, antioxidant, and immunomodulatory. Such peptides exist in all living organism like plants, animals, marine organism and also present in food products derived from them. BPs obtained from dairy food products, cereals, vegetables have been gaining much more importance now-a-days, but little work has been done on bioactive peptides obtained from medicinal plants. Some of the medicinal plants such as Tinospora cordifolia Sterculia foetida, Benincasa hispida, Parkia speciosa, Linum usitatissimum, Salvia hispanica and Ziziphus jujube have been explored for bioactive peptides. Current review is aimed to provide a complete information of medicinal plants derived BPs along with the surge of new materials, new plants which will provide more solutions for handling some of the major human health problems of twenty-first century. This review will also be helpful to researchers in providing valuable information about the extraction, separation, characterization of BPs, their known peptide sequences and various pharmacological activities exerted by medicinal plants-derived bioactive peptides.

New Insight into Bacterial Interaction with the Matrix of Plant-Based Fermented Foods

Microorganisms have been harnessed to process raw plants into fermented foods. The adaptation to a variety of plant environments has resulted in a nearly inseparable association between the bacterial species and the plant with a characteristic chemical profile. Lactic acid bacteria, which are known for their ability to adapt to nutrient-rich niches, have altered their genomes to dominate specific habitats through gene loss or gain. Molecular biology approaches provide a deep insight into the evolutionary process in many bacteria and their adaptation to colonize the plant matrix. Knowledge of the adaptive characteristics of microorganisms facilitates an efficient use thereof in fermentation to achieve desired final product properties. With their ability to acidify the environment and degrade plant compounds enzymatically, bacteria can modify the textural and organoleptic properties of the product and increase the bioavailability of plant matrix components. This article describes selected microorganisms and their competitive survival and adaptation in fermented fruit and vegetable environments. Beneficial changes in the plant matrix caused by microbial activity and their beneficial potential for human health are discussed as well.

Bioactive peptides from foods: production, function, and application

Bioactive peptides are a class of peptides with special physiological functions and have potential applications in human health and disease prevention. Bioactive peptides have gained much research attention because they affect the cardiovascular, endocrine, immune, and nervous systems. Recent research has reported that bioactive peptides are of great value for physiological function regulation, including antioxidation, anti-hypertension, antithrombosis, antibacterial properties, anti-cancer, anti-inflammation, anti-diabetic, anti-obesity, cholesterol-lowering, immunoregulation, mineral binding and opioid activities. The production of food-derived bioactive peptides is mainly through the hydrolysis of digestive enzymes and proteolytic enzymes or microbial fermentation. The purpose of this review is to introduce the production, function, application, challenges, and prospects of food-derived bioactive peptides.

Plant Bioactive Peptides: Current Status and Prospects Towards Use on Human Health

Large numbers of bioactive peptides with potential applications in protecting against human diseases have been identified from plant sources. In this review, we summarized recent progress in the research of plant-derived bioactive peptides, encompassing their production, biological effects, and mechanisms. This review focuses on antioxidant, antimicrobial, antidiabetic, and anticancer peptides, giving special attention to evidence derived from cellular and animal models. Studies investigating peptides with known sequences and well-characterized peptidic fractions or protein hydrolysates will be discussed. The use of molecular docking tools to elucidate inter-molecular interactions between bioactive peptides and target proteins is highlighted. In conclusion, the accumulating evidence from in silico, in vitro and in vivo studies to date supports the envisioned applications of plant peptides as natural antioxidants as well as health-promoting agents. Notwithstanding, much work is still required before the envisioned applications of plant peptides can be realized. To this end, future researches for addressing current gaps were proposed.

Effects of Lacto-Fermented Agricultural By-Products as a Natural Disinfectant against Post-Harvest Diseases of Mango (Mangifera indica L.)

Background: the antagonism activity of lactic acid bacteria metabolites has the potential to prevent fungal growth on mango. Methods: the potential of developing natural disinfectant while using watermelon rinds (WR), pineapple (PP), orange peels (OP), palm kernel cake (PKC), and rice bran (RB), via lacto-fermentation was investigated. The obtained lactic acid bacteria (LAB) metabolites were then employed and the in vitro antifungal activity toward five spoilage fungi of mango was tested through liquid and solid systems. Besides, the effect of the produced disinfectant on the fungal growth inhibition and quality of mango was investigated. Results: the strains Lactobacillus plantarum ATCC8014 and Lactobacillus fermentum ATCC9338 growing in the substrates PKC and PP exhibited significantly higher in vitro antifungal activity against Colletotrichum gloeosporioides and Botryodiplodia theobromae as compared to other tested LAB strains and substrates. The in-situ results demonstrated that mango samples that were treated with the disinfectant produced from PKC fermented with L. plantarum and L. fermentum had the lowest disease incidence and disease severity index after 16 days shelf life, as well as the lowest conidial concentration. Furthermore, PKC that was fermented by L. fermentum highly maintained the quality of the mango. Conclusions: lactic acid fermentation of PKC by L. fermentum demonstrated a high potential for use as a natural disinfectant to control C. gloeosporioides and B. theobromae on mango.

Bioactive peptides from food fermentation: A comprehensive review of their sources, bioactivities, applications, and future development

Bioactive peptides (BPs) are specific protein fragments that exert various beneficial effects on human bodies and ultimately influence health, depending on their structural properties and amino acid composition and sequences. By offering promising solutions to solve diverse health issues, the production, characterization, and applications of food-derived BPs have drawn great interest in the current literature and are of particular interest to the food and pharmaceutical industries. The microbial fermentation of protein from various sources is indubitably a novel way to produce BPs with numerous beneficial health effects. Apart from its lower cost as compared to enzymes, the BPs produced from microbial fermentation can be purified without further hydrolysis. Despite these features, current literature shows dearth of information on the BPs produced from food via microbial fermentation. Hence, there is a strong necessity to explore the BPs obtained from food fermentation for the development of commercial nutraceuticals and functional foods. As such, this review focuses on the production of BPs from different food sources, including the extensively studied milk and milk products, with emphasis on microbial fermentation. The structure-activity (antihypertensive, antioxidant, antimicrobial, opiate-like, anti-inflammatory, anticancer/antiproliferative, antithrombotic, hypolipidemic, hypocholesterolemic, and mineral binding) relationship, potential applications, future development, and challenges of BPs obtained from food fermentation are also discussed.

Current Trends of Bioactive Peptides-New Sources and Therapeutic Effect

Generally, bioactive peptides are natural compounds of food or part of protein that are inactive in the precursor molecule. However, they may be active after hydrolysis and can be transported to the active site. Biologically active peptides can also be synthesized chemically and characterized. Peptides have many properties, including antihypertensive, antioxidant, antimicrobial, anticoagulant, and chelating effects. They are also responsible for the taste of food or for the inhibition of enzymes involved in the development of diseases. The scientific literature has described many peptides with bioactive properties obtained from different sources. Information about the structure, origin, and properties of peptides can also be found in many databases. This review will describe peptides inhibiting the development of current diseases, peptides with antimicrobial properties, and new alternative sources of peptides based on the current knowledge and documentation of their bioactivity. All these issues are part of modern research on peptides and their use in current health or technological problems in food production.