Electroseparation of an antibacterial peptide fraction from snow crab by-products hydrolysate by electrodialysis with ultrafiltration membranes

Antimicrobial peptides derived from food byproducts: Sources, production, purification, applications, and challenges

Food wastes can be a valuable reservoir of bioactive substances that can serve as natural preservatives in foods or as functional ingredients with potential health benefits. The antimicrobial properties of protein hydrolysates, especially antimicrobial peptides (AMPs) derived from food byproducts (FBs), have been extensively explored. These protein fragments are defined by their short length, low molecular weight, substantial content of hydrophobic and basic amino acids, and positive net charge. The intricate mechanisms by which these peptides exert their antimicrobial effects on microorganisms and pathogens have been elaborately described. This review also focuses on techniques for producing and purifying AMPs from diverse FBs, including seafood, livestock, poultry, plants, and dairy wastes. According to investigations, incorporating AMPs as additives and alternatives to chemical preservatives in food formulations and packaging materials has been pursued to enhance both consumer health and the shelf life of foods and their products. However, challenges associated with the utilization of AMPs derived from food waste depend on their interaction with the food matrix, acceptability, and commercial viability. Overall, AMPs can serve as alternative safe additives, thereby ensuring the safety and prolonging the storage duration of food products based on specific regulatory approvals as recommended by the respective safety authorities.

Electrodialysis Processes an Answer to Industrial Sustainability: Toward the Concept of Eco-Circular Economy?-A Review

Wastewater and by-product treatments are substantial issues with consequences for our society, both in terms of environmental impacts and economic losses. With an overall global objective of sustainable development, it is essential to offer eco-efficient and circular solutions. Indeed, one of the major solutions to limit the use of new raw materials and the production of wastes is the transition toward a circular economy. Industries must find ways to close their production loops. Electrodialysis (ED) processes such as conventional ED, selective ED, ED with bipolar membranes, and ED with filtration membranes are processes that have demonstrated, in the past decades and recently, their potential and eco-efficiency. This review presents the most recent valorization opportunities among different industrial sectors (water, food, mining, chemistry, etc.) to manage waste or by-product resources through electrodialysis processes and to improve global industrial sustainability by moving toward circular processes. The limitations of existing studies are raised, especially concerning eco-efficiency. Indeed, electrodialysis processes can be optimized to decrease energy consumption and costs, and to increase efficiency; however, eco-efficiency scores should be determined to compare electrodialysis with conventional processes and support their advantages. The review shows the high potential of the different types of electrodialysis processes to treat wastewaters and liquid by-products in order to add value or to generate new raw materials. It also highlights the strong interest in using eco-efficient processes within a circular economy. The ideal scenario for sustainable development would be to make a transition toward an eco-circular economy.

A review on membrane separation processes focusing on food industry environment-friendly processes

Food processing industries have led to several environmental impacts due to their high water and energy consumption, as well as soil and water bodies' contamination through improper waste disposal. Membrane Separation Processes (MSP) emerge as an important alternative to enable the adoption of sustainable processes by food industries, since satisfying the requests of innovative processes and equipment design, such as smaller, cleaner, more energy-efficient processes (mild conditions) without the usage of chemical agents. Membrane-based processes fulfill these requirements, and their potential has been broadly recognized in the last few years. This review provides a comprehensive and up-to-date overview of the application of MSP in sustainable processes in the different segments of the food industry over the last 10 years. Waste and wastewater treatment, recovery of valuable compounds and water for reuse, and alternatives to high energy consumption processes were identified as sustainable processes in this context. One trend found is the potential for adding value to production chains by obtaining valuable compounds that have not been explored yet. As a perspective for future research, this review showed that it is advisable to implement MSP in different industrial environments in order to make current processes environmentally sustainable and less polluting.

Exploiting of Secondary Raw Materials from Fish Processing Industry as a Source of Bioactive Peptide-Rich Protein Hydrolysates

Developing peptide-based drugs are very promising to address many of the lifestyle mediated diseases which are prevalent in a major portion of the global population. As an alternative to synthetic peptide-based drugs, derived peptides from natural sources have gained a greater attention in the last two decades. Aquatic organisms including plants, fish and shellfish are known as a rich reservoir of parent protein molecules which can offer novel sequences of amino acids in peptides, having unique bio-functional properties upon hydrolyzing with proteases from different sources. However, rather than exploiting fish and shellfish stocks which are already under pressure due to overexploitation, the processing discards, regarded as secondary raw material, could be a potential choice for peptide based therapeutic development strategies. In this connection, we have attempted to review the scientific reports in this area of research that deal with some of the well-established bioactive properties, such as antihypertensive, anti-oxidative, anti-coagulative, antibacterial and anticarcinogenic properties, with reference to the type of enzymes, substrate used, degree of particular bio-functionality, mechanism, and wherever possible, the active amino acid sequences in peptides. Many of the studies have been conducted on hydrolysate (crude mixture of peptides) enriched with low molecular bioactive peptides. In vitro and in vivo experiments on the potency of bioactive peptides to modulate the human physiological functions beneficially have demonstrated that these peptides can be used in the prevention and treatment of non-communicable lifestyle mediated diseases. The information synthesized under this review could serve as a point of reference to drive further research on and development of functionally active therapeutic natural peptides. Availability of such scientific information is expected to open up new zones of investigation for adding value to underutilized secondary raw materials, which in turn paves the way for sustainability in fish processing. However, there are significant challenges ahead in exploring the fish waste as a source of bioactive peptides, as it demands more studies on mechanisms and structure–function relationship understanding as well as clearance from regulatory and statutory bodies before reaching the end user in the form of supplement or therapeutics.

Identification of Peptides Implicated in Antibacterial Activity of Snow Crab Hepatopancreas Hydrolysates by a Bioassay-Guided Fractionation Approach Combined with Mass Spectrometry

Snow crab (Chionoecetes opilio) by-products are a rich source of biomolecules, such as lipids, proteins, and chitin, which have not been extensively investigated. This study aims to identify antibacterial peptides to enhance the value of C. opilio by-products. After hydrolysis of different component parts using Protamex®, and concentration by solid-phase extraction, the resulting fractions were tested for antibacterial activity against Escherichia coli, Listeria innocua, and Vibrio parahaemolyticus. Hepatopancreas was the only tissue to display antibacterial activity detected using this protocol. Four fractions obtained with and without enzymatic hydrolysis of hepatopancreas followed by SPE C18 fractionation and elution with 50 and 80% acetonitrile demonstrated bacteriostatic activity against L. innocua HPB13, from concentrations of 0.30 to 43.05 mg/mL of peptides/proteins. Eleven peptides sharing at least 80% amino acid homology with four antimicrobial peptides were identified by mass spectrometry. Two peptides had homology to crustin-like and yellowfin tuna GAPDH antimicrobial peptides belonging to the marine organisms Penaeus monodon and Thunnus albacares, respectively. Other peptide sequence homologies were also identified: Odorranain-C7 from the frog Odorrana grahami and a predicted antibacterial peptide in the Asian ladybeetle Harmonia axyridis. These active peptides may represent a novel group of bioactive peptides deserving further investigation as food preservatives.

Harnessing slaughterhouse by-products: From wastes to high-added value natural food preservative

Blood, from slaughterhouses, is an inevitable part of meat production, causing environmental problems due to the large volumes recovered and its low valorization. However, the α137-141 peptide, a natural antimicrobial peptide, can be obtained after hydrolysis of hemoglobin, the main constituent of blood red part. To recover it at a sufficient concentration for antimicrobial applications, a new sustainable technology, called electrodialysis with ultrafiltration membrane (EDUF), was investigated. The α137-141 concentration was increased about 4-fold at a feed peptide concentration of 8% with an enrichment factor above 24-fold. This feed peptide concentration also needed the lowest relative energy consumption. Moreover, this peptide fraction protected meat against microbial growth, as well as rancidity, during 14 days under refrigeration. This peptide fraction was validated as a natural preservative and substitute for synthetic additives against food spoilage. Finally, producing antimicrobial/antioxidant peptide from wastes by EDUF fits perfectly with the concept of circular economy.

Synthesis and antibacterial activity of new peptides from Alfalfa RuBisCO protein hydrolysates and mode of action via a membrane damage mechanism against Listeria innocua

In this work we evaluated the mode of action of six new synthesized peptides (Met-Asp-Asn; Glu-leu-Ala-Ala-Ala-Cys; Leu-Arg-Asp-Asp-Phe; Gly-Asn-Ala-Pro-Gly-Ala-Val-Ala; Ala-Leu-Arg-Met-Ser-Gly and Arg-Asp-Arg-Phe-Leu), previously identified, from the most active peptide fractions of RuBisCO peptic hydrolysate against Listeria innocua via a membrane damage mechanism. Antibacterial effect and the minimum inhibitory concentrations (MIC) of these peptides were evaluated against six strains and their hemolytic activities towards bovine erythrocytes were determined. Prediction of the secondary structure of peptides indicated that these new antibacterial peptides are characterized by a short peptide chains (3-8 amino acid) and a random coli structure. Moreover, it was observed that one key characteristic of antibacterial peptides is the presence of specific amino acids such as cysteine, glycine, arginine and aspartic acid. In addition the determination of the extracellular potassium concentration revealed that treatment with pure RuBisCO peptides could cause morphological changes of L. innocua and destruction of the cell integrity via irreversible membrane damage. The results could provide information for investigating the antibacterial model of antibacterial peptides derived from RuBisCO protein hydrolysates.

Effect of skim milk treated with high hydrostatic pressure on permeate flux and fouling during ultrafiltration

Ultrafiltration (UF) is largely used in the dairy industry to generate milk and whey protein concentrate for standardization of milk or production of dairy ingredients. Recently, it was demonstrated that high hydrostatic pressure (HHP) extended the shelf life of milk and improved rennet coagulation and cheese yield. Pressurization also modified casein micelle size distribution and promoted aggregation of whey proteins. These changes are likely to affect UF performance. Consequently, this study determined the effect of skim milk pressurization (300 and 600 MPa, 5 min) on UF performance in terms of permeate flux decline and fouling. The effect of HHP on milk proteins was first studied and UF was performed in total recycle mode at different transmembrane pressures to determine optimal UF operational parameters and to evaluate the effect of pressurization on critical and limiting fluxes. Ultrafiltration was also performed in concentration mode at a transmembrane pressure of 345 kPa for 130 or 140 min to evaluate the decline of permeate flux and to determine fouling resistances. It was observed that average casein micelle size decreased by 32 and 38%, whereas β-lactoglobulin denaturation reached 30 and 70% at 300 and 600 MPa, respectively. These results were directly related to UF performance because initial permeate fluxes in total recycle mode decreased by 25% at 300 and 600 MPa compared with nonpressurized milk, critical flux, and limiting flux, which were lower during UF of milk treated with HHP. During UF in concentration mode, initial permeate fluxes were 30% lower at 300 and 600 MPa compared with the control, but the total flux decline was higher for nonpressurized milk (62%) compared with pressure-treated milk (30%). Fouling resistances were similar, whatever the treatment, except at 600 MPa where irreversible fouling was higher. Characterization of the fouling layer showed that caseins and β-lactoglobulin were mainly involved in membrane fouling after UF of pressure-treated milk. Our results demonstrate that HHP treatment of skim milk drastically decreased UF performance.

Selective separation and concentration of antihypertensive peptides from rapeseed protein hydrolysate by electrodialysis with ultrafiltration membranes

Rapeseed protein isolate was subjected to alcalase digestion to obtain a protein hydrolysate that was separated into peptide fractions using electrodialysis with ultrafiltration membrane (EDUF) technology. The EDUF process (6h duration) led to isolation of three peptide fractions: anionic (recovered in KCl-1 compartment), cationic (recovered in KCl-2 compartment), and those that remained in the feed compartment, which was labeled final rapeseed protein hydrolysate (FRPH). As expected the KCl-1 peptides were enriched in negatively-charged (43.57%) while KCl-2 contained high contents of positively-charged (28.35%) amino acids. All the samples inhibited angiotensin converting enzyme (ACE) and renin activities in dose-dependent manner with original rapeseed protein hydrolysate having the least ACE-inhibitory IC50 value of 0.0932±0.0037 mg/mL while FRPH and KCl-2 had least renin-inhibitory IC50 values of 0.47±0.05 and 0.55±0.06 mg/mL, respectively. Six hours after oral administration (100 mg/kg body weight) to spontaneously hypertensive rats, the FRPH produced the maximum systolic blood pressure reduction of -51 mmHg.

Enhancement of glucose uptake in muscular cell by soybean charged peptides isolated by electrodialysis with ultrafiltration membranes (EDUF): activation of the AMPK pathway

Soy peptides consumption has been associated with beneficial effects in type 2 diabetes patients. However, the peptide fractions responsible for these effects, and their mechanisms of action, have not been identified yet. In this study, we have isolated soybean peptides by electrodialysis with an ultrafiltration membrane (EDUF) at 50 V/100 kDa, and tested them for their capacity to improve glucose uptake in L6 muscle cells. We observed that these fractions were able to significantly enhance glucose uptake in the presence of insulin. The reported bioactivity would be due to the low molecular weight peptides (300-500 Da) recovered. Moreover, we observed that an enhancement of glucose uptake was correlated to the activation of the AMPK enzyme, well known for its capacity to increase glucose uptake in muscle cells. To our knowledge, this is the first time that bioactive peptides with glucose uptake activity have been isolated from a complex soy matrix, and that the implication of AMPK in it is demonstrated.