Effect of Microwave Treatments on Antioxidant Activity and Antigenicity of Fish Frame Protein Hydrolysates

Protein and water recovery from tuna defrosting wastewater

The objective of this research was to recover protein and water from tuna defrosting wastewater. Tuna defrosting wastewater (TDW) was concentrated, and salt protein residue (PR) was separated from concentrate TDW (cTDW). Protein in the cTDW was precipitated (PP). Salt was removed from PR and PP by using hot water (60 °C). PR and PP were dried at 50 °C before analysis for total protein, amino acid profile and salt content. Salty protein solution (PS) following salt removal from the precipitate was collected and concentrated. Then salt cPS was desalted by Sephadex G-25, and the elution was collected and concentrated. The resulting cPS was analyzed for pH, total protein, salt content, amino acid profile and antioxidant properties. Water from the protein recovery procedure was collected and analyzed for biological qualities (heterotrophic plate count, coliform bacteria, E. coli, Staphylococcus aureus, Salmonella spp. and Clostridium perfringens), physical qualities (apparent color, turbidity, pH) and chemical qualities (total dissolved solids, total hardness and sulfate).The results showed that cTDW contained 11.57 ± 0.03 % protein and 3.36 ± 0.03% NaCl. After salt was removed, the dried PR and PP contained 33.10 ± 0.16% and 6.92 ± 0.13% protein, respectively, and 0.23 ± 0.00% and 0.05 ± 0.00% NaCl, respectively. Dried PR contained 9 essential amino acids at higher concentrations than in PP. Concentrated PS contained 3.15 ± 0.12% protein and no NaCl. Histidine (254.15 mg/100 g) was the dominant amino acid in cPS. Antioxidant properties are shown by values for DPPH, ABTS and FRAP. The physical, chemical and bacterial parameters of recovered water met the guidelines for drinking water quality. These results indicate that recovery of protein and water is possible in fish processing, which could reduce costs for processors and benefit the environment.

Current state of insect proteins: extraction technologies, bioactive peptides and allergenicity of edible insect proteins

This review aims to provide an updated overview of edible insect proteins and the bioactivity of insect-derived peptides. The essential amino acid content of edible insects is compared with well-known protein sources to demonstrate that edible insects have the potential to cover the protein quality requirements for different groups of the population. Then the current methodologies for insect protein extraction are summarized including a comparison of the protein extraction yield and the final protein content of the resulting products for each method. Furthermore, in order to improve our understanding of insect proteins, their functional properties (such as solubility, foaming capacity, emulsifying, gelation, water holding capacity and oil holding capacity) are discussed. Bioactive peptides can be released according to various enzymatic hydrolysis protocols. In this context, the bioactive properties of insect peptides (antihypertensive, antidiabetic, antioxidant and anti-inflammatory properties) have been discussed. However, the allergens present in insect proteins are still a major concern and an unsolved issue for insect-based product consumption; thus, an analysis of cross reactivity and the different methods available to reduce allergenicity are proposed. Diverse studies of insect protein hydrolysates/peptides have been ultimately promoting the utilization of insect proteins for future perspectives and the emerging processing technologies to enhance the wider utilization of insect proteins for different purposes.

Tackling food allergens-The role of food processing on proteins' allergenicity

This chapter examines how innovative and emerging food processing technologies, such as those that use heat, electricity, electromagnetic waves, and pressure, can modify protein denaturation, aggregation, and intermolecular interactions pathways, which can result in varying immunoreactive responses. It emphasizes the need to understand how these processing methods affect the protein epitopes recognized by antibodies and their respective priming pathways, especially during the sensitization stage that precedes an allergic response. Although traditional processing methods have been investigated, the impact of novel technologies on food protein allergenicity remains largely unknown. The chapter specifically focuses on milk proteins, which have clinical significance and are associated with cow's milk allergy, one of the most common food allergies in young children. Additionally, it examines potential scientific advancements that novel processing methods may bring to this field.

Microwave processing technology influences the functional and structural properties of fish gelatin

The objective of this study was to evaluate the effects of microwave processing technology (MPT, 240-800 W, 1 and 4 min) on the functional and structural properties of fish gelatin (FG). It showed that MPT could increase gel strength and texture properties of FG, especially for 240 W. MPT greatly increased emulsifying activity index (EAI) of FG, but decreased its emulsion stability index (ESI). Rheology results showed that MPT increased viscosity of FG, but decreased gelation times. Intrinsic fluorescence and Fourier transform infrared (FTIR) spectroscopy results indicated that MPT could unfold gelatin, contributing to the formation of H-bonds. Scanning electron microscopy (SEM) analysis revealed that low power and short time of MPT-treated gelatin gels had much more dense and less voids. This work provided guidance for the applications of MPT to improve the functional properties of FG, and the results show that MPT-treated FG can replace mammalian gelatin and meet the religious requirement.

Transformation of Seafood Side-Streams and Residuals into Valuable Products

Seafood processing creates enormous amounts of side-streams. This review deals with the use of seafood side-streams for transformation into valuable products and identifies suitable approaches for making use of it for different purposes. Starting at the stage of catching fish to its selling point, many of the fish parts, such as head, skin, tail, fillet cut-offs, and the viscera, are wasted. These parts are rich in proteins, enzymes, healthy fatty acids such as monounsaturated and polyunsaturated ones, gelatin, and collagen. The valuable biochemical composition makes it worth discussing paths through which seafood side-streams can be turned into valuable products. Drawbacks, as well as challenges of different aquacultures, demonstrate the importance of using the various side-streams to produce valuable compounds to improve economic performance efficiency and sustainability of aquaculture. In this review, conventional and novel utilization approaches, as well as a combination of both, have been identified, which will lead to the development of sustainable production chains and the emergence of new bio-based products in the future.

Recent Insight on Edible Insect Protein: Extraction, Functional Properties, Allergenicity, Bioactivity, and Applications

Due to the recent increase in the human population and the associated shortage of protein resources, it is necessary to find new, sustainable, and natural protein resources from invertebrates (such as insects) and underutilized plants. In most cases, compared to plants (e.g., grains and legumes) and animals (e.g., fish, beef, chicken, lamb, and pork), insect proteins are high in quality in terms of their nutritional value, total protein content, and essential amino acid composition. This review evaluates the recent state of insects as an alternative protein source from production to application; more specifically, it introduces in detail the latest advances in the protein extraction process. As an alternative source of protein in food formulations, the functional characteristics of edible insect protein are comprehensively presented, and the risk of allergy associated with insect protein is also discussed. The biological activity of protein hydrolyzates from different species of insects (Bombyx mori, Hermetia illucens, Acheta domesticus, Tenebrio molitor) are also reviewed, and the hydrolysates (bioactive peptides) are found to have either antihypertensive, antioxidant, antidiabetic, and antimicrobial activity. Finally, the use of edible insect protein in various food applications is presented.

Application of enzymes in the preparation of wheat germ polypeptides and their biological activities

Wheat germ, a byproduct of wheat industrial processing, contains 30% protein and is a comprehensive source of plant-based protein. But a large amount of wheat germs are disposed of as waste every year. Wheat germ protein can be hydrolyzed into polypeptides with antioxidant, antihypertensive, anti-tumor, bacteriostatic and other activities. At present, researches on the hydrolysis of wheat germ protein and the preparation of bioactive peptides from wheat germ protein have attracted increasing attentions. However, the traditional protein hydrolysis method, protease hydrolysis, can no longer meet the market's needs for efficient production. Various auxiliary means, such as ultrasound, microwave and membrane separation, were applied to boost the yield and biological activity of wheat germ peptides by enzymatic hydrolysis. Under ultrasound and microwave, the protein structure may expand to increase the binding sites between enzyme and substrate and promote hydrolysis efficiency. Membrane separation is applied to separate products from enzymatic hydrolysate to reduce the inhibitory effect of the product on the hydrolysis reaction. The paper reviewed the hydrolysis methods of wheat germ protein and summarized the biological activity of wheat germ peptides to provide references for further study of wheat germ peptides.

Oxidative Stress Protection by Canary Seed (Phalaris canariensis L.) Peptides in Caco-2 Cells and Caenorhabditis elegans

During oxidative stress, degenerative diseases such as atherosclerosis, Alzheimer’s, and certain cancers are likely to develop. Recent research on canary seed (Phalaris canariensis) peptides has demonstrated the high in vitro antioxidant potential. Thus, this study aimed to assess the cellular and in vivo antioxidant capacity of a low-molecular-weight (<3 kDa) canary seed peptide fraction (CSPF) using Caco-2 cells and the Caenorhabditis elegans model. The results show that the CSPF had no cytotoxicity effect on Caco-2 cells at any tested concentration (0.3−2.5 mg/mL). Additionally, the cellular antioxidant activity (CAA) of the CSPF was concentration-dependent, and the highest activity achieved was 80% by the CSPF at 2.5 mg/mL. Similarly, incubation with the CSPF significantly mitigated the acute and chronic oxidative damage, extending the lifespan of the nematodes by 88 and 61%, respectively. Furthermore, it was demonstrated that the CSPF reduced the accumulation of reactive oxygen species (ROS) to safe levels after sub-lethal doses of pro-oxidant paraquat. Quantitative real-time PCR revealed that the CSPF increased the expression of oxidative-stress-response-related gene GST-4. Overall, these results show that the CSPFs relied on GST-4 upregulation and scavenging of free radicals to confer oxidative stress protection and suggest that a CSPF can be used as a natural antioxidant in foods for health applications.

Production of nutty-like flavour from soybean protein isolate hydrolysate pretreated or assisted by microwave irradiation: impact of encapsulation on nutty flavour quality

The aim of this study was to prepare a nutty-like flavour from enzymatic hydrolysates of soybean protein isolate pretreated or assisted by microwave heating. In both cases the time of microwave heating was optimized and degree of hydrolysis (DH) and content of free amino acids in each hydrolysate were determined and compared with those of hydrolysate prepared by conventional method (E-HSC). The hydrolysates showed the best results were used as main precursors of nutty flavour. The generated volatiles were subjected to GC-MS analysis and odour evaluation. The effect of encapsulation and storage on the nutty flavour was evaluated. The results revealed that the hydrolysates pretreated (E-HSMP₇) or assisted (E-HSMA₆) by microwave at 7 and 6 min, respectively showed a significant increase in DH. The nutty flavour generated from these hydrolysates (NFMP₇ and NFMA₆) were dominated with pyrazines whereas, the volatiles from E-HSC (NFC) dominated with furans. NFMA₆ showed the highest intensity of nutty and overall acceptability notes, compared with NFMP₇ and NFC. Encapsulation resulted in a significant decrease in pyrazines, which are responsible for the nutty note. The significant increase in nutty aroma intensity of the stored encapsulated sample was correlated to the increase in pyrazines.

Antioxidant and Antimicrobial Peptides Derived from Food Proteins

Recently, the demand for food proteins in the market has increased due to a rise in degenerative illnesses that are associated with the excessive production of free radicals and the unwanted side effects of various drugs, for which researchers have suggested diets rich in bioactive compounds. Some of the functional compounds present in foods are antioxidant and antimicrobial peptides, which are used to produce foods that promote health and to reduce the consumption of antibiotics. These peptides have been obtained from various sources of proteins, such as foods and agri-food by-products, via enzymatic hydrolysis and microbial fermentation. Peptides with antioxidant properties exert effective metal ion (Fe2+/Cu2+) chelating activity and lipid peroxidation inhibition, which may lead to notably beneficial effects in promoting human health and food processing. Antimicrobial peptides are small oligo-peptides generally containing from 10 to 100 amino acids, with a net positive charge and an amphipathic structure; they are the most important components of the antibacterial defense of organisms at almost all levels of life-bacteria, fungi, plants, amphibians, insects, birds and mammals-and have been suggested as natural compounds that neutralize the toxicity of reactive oxygen species generated by antibiotics and the stress generated by various exogenous sources. This review discusses what antioxidant and antimicrobial peptides are, their source, production, some bioinformatics tools used for their obtainment, emerging technologies, and health benefits.

Fish Gelatin: Current Nutritional, Medicinal, Tissue Repair Applications and Carrier of Drug Delivery

Gelatin is obtained via partial denaturation of collagen and is extensively used in various industries. The majority of gelatin utilized globally is derived from a mammalian source. Several health and religious concerns associated with porcine/bovine gelatin were reported. Therefore, gelatin from a marine source is widely being investigated for its efficiency and utilization in a variety of applications as a potential substitute for porcine/bovine gelatin. Although fish gelatin is less durable and possesses lower melting and gelling temperatures compared to mammal-derived gelatin, various modifications are being reported to promote its rheological and functional properties to be efficiently employed. The present review describes in detail the current innovative applications of fish gelatin involving the food industry, drug delivery and possible therapeutic applications. Gelatin bioactive molecules may be utilized as carriers for drug delivery. Due to its versatility, gelatin can be used in different carrier systems, such as microparticles, nanoparticles, fibers and hydrogels. The present review also provides a perspective on the other potential pharmaceutical applications of fish gelatin, such as tissue regeneration, antioxidant supplementation, antihypertensive and anticancer treatments.

Edible insects, a valuable protein source from ancient to modern times

The current COVID-19 pandemic has demonstrated that we are not prepared to deal with food security amid unexpected situations; the FAO (Food and Agriculture Organization) has stipulated that the future of our food & agriculture looks challenging toward the year 2050; primarily in response to the fact that global population is expected to increase by 9 billion people by 2050. Although entomophagy has been practiced by humans for thousands of years, until recently, edible insects have gained special attention due to their high nutritional value (particularly their high protein and essential amino acid content) and lower environmental impact that could help alleviate the global food demand. Edible insects are classified into eight main orders belonging to Blattodea (cockroaches and termites), Coleoptera (beetles), Diptera (flies), Hemiptera (cicadas, stink bugs), Hymenoptera (bees, wasps, ants), Lepidoptera (butterflies, moths), Odonata (dragonflies), and Orthoptera (crickets, grasshoppers, locusts). Several traditional cooking (e.g., boiling, roasting, sun-drying) and processing technologies (e.g., pasteurization, enzymatic proteolysis, high pressure processing) have shown that it is feasible to prepare safe and nutritious insects and/or foods with insects. Nevertheless, challenges associated with consumers acceptance to eat insects, as well as potential presence of anti-nutritive factors and allergens, need to be carefully evaluated as the industry grows in the coming years. Foreseeing such food shortages during pandemics and future food security concerns, consumers, scientists, and the food industry need to consider the value of farming insects as promising protein sources.

Isolation and proteomic characterization of tropomyosin extracted from edible insect protein

Edible insects are considered promising sustainable protein sources. Thermal treatments and proteolysis are commonly used to improve their safety and quality. However, their allergenicity remains mostly unexplored. Tropomyosin, a major insect pan-allergen, can be used to study processing effects on its immunoreactivity. In this study, selective precipitation was used to extract tropomyosin from heated and protease-treated crickets. Immunoinformatics predicted 31 epitope regions, while proteomic analysis suggested decreased amounts of intact epitope regions in microwave-heated/protease-treated crickets. Tropomyosin peptide sequences were identified in higher abundance in convection-heated samples. Finally, tropomyosin immunoreactivity by immunoblotting and ELISA, revealed that protease treatments under microwave heating had lower (p < 0.05) IgE and IgG reactivity. Based on results, processing insects using proteolysis and microwave-heating could be effective for generating hypoallergenic cricket protein ingredients. The use of proteomics and bioinformatics proved to be useful tools in understanding the impact of processing on allergenic reactivity of insect proteins.

Targeted Phenolic Characterization and Antioxidant Bioactivity of Extracts from Edible Acheta domesticus

With entomophagy gaining popularity in the Western hemisphere as a solution for future food insecurity, research on alternative protein sources, such as edible insects, has become relevant. Most of the research performed on insects has been on their nutritional qualities; however, little is known regarding bioactive compounds, such as polyphenols, that, if present in the insect, could provide additional benefits when the insect is consumed. In this study, methanolic extracts of Acheta domesticus from two farms and their corresponding feeds were obtained using a microwave-assisted extraction. Targeted phenolic characterization was accomplished through LC-MS/MS leading to the identification of 4-hydroxybenzoic acid, p-coumaric acid, ferulic acid, and syringic acid as major phenolic compounds in both A. domesticus extracts. Furthermore, the in vitro antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical cation (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical assays demonstrating the superior quenching activity of the A. domesticus extracts compared to the feeds. The discovery of phenolic compounds in A. domesticus implies the ability of this insect species to sequester and absorb dietary phenolics leading to possible added health benefits when consumed.

Thermal processing implications on the digestibility of meat, fish and seafood proteins

Thermal processing is an inevitable part of the processing and preparation of meat and meat products for human consumption. However, thermal processing techniques, both commercial and domestic, induce modifications in muscle proteins which can have implications for their digestibility. The nutritive value of muscle proteins is closely related to their digestibility in the gastrointestinal tract and is determined by the end products that it presents in the assimilable form (amino acids and small peptides) for the absorption. The present review examines how different thermal processing techniques, such as sous-vide, microwave, stewing, roasting, boiling, frying, grilling, and steam cooking, affect the digestibility of muscle proteins in the gastrointestinal tract. By altering the functional and structural properties of muscle proteins, thermal processing has the potential to influence the digestibility negatively or positively, depending on the processing conditions. Thermal processes such as sous-vide can induce favourable changes, such as partial unfolding or exposure of cleavage sites, in muscle proteins and improve their digestibility whereas processes such as stewing and roasting can induce unfavourable changes, such as protein aggregation, severe oxidation, cross linking or increased disulfide (S-S) content and decrease the susceptibility of proteins during gastrointestinal digestion. The review examines how the underlying mechanisms of different processing conditions can be translated into higher or lower protein digestibility in detail. This review expands the current understanding of muscle protein digestion and generates knowledge that will be indispensable for optimizing the digestibility of thermally processed muscle foods for maximum nutritional benefits and optimal meal planning.

Study of biological activities and physicochemical properties of Yamú (Brycon siebenthalae) viscera hydrolysates in sodium alginate-based edible coating solutions

The fishing industry produces waste such as viscera, which is an environmental problem for many countries. Obtaining protein from these wastes are useful for the food industry. In this study, the chemical composition, amino acid profile, solubility, digestibility and thermal properties of Yamú protein isolate (PI) and its hydrolysates obtained by enzymatic hydrolysis were characterized. The hydrolysates (0.05, 0.1, 0.5, 1 and 2% w/v) were mixed with a sodium alginate-based solution to form an edible coating solution (ECS). Antioxidant capacity antimicrobial activity, Zeta potential (ζ) and adsorption kinetics properties were determined. PI contains 88% (w/w) protein showing better solubility, digestibility and thermal stability properties. The hydrolysate concentrations with DPPH inhibitory ECS were 0.1 and 0.5% (w/v). The kinetic properties of ECS showed good stability and excellent adsorption. These results suggest that this Yamú protein has high nutritional potential as an ingredient for the production of functional foods.

In Silico Prediction and In Vitro Assessment of Multifunctional Properties of Postbiotics Obtained From Two Probiotic Bacteria

In this study, a global metabolite profile using Raman spectroscopy analysis was obtained in order to predict, by an in silico prediction of activity spectra for substance approach, the bioactivities of the intracellular content (IC) and cell wall (CW) fractions obtained from Lactobacillus casei CRL 431 and Bacillus coagulans GBI-30 strains. Additionally, multifunctional in vitro bioactivity of IC and CW fractions was also assessed. The metabolite profile revealed a variety of compounds (fatty acids, amino acids, coenzyme, protein, amino sugars), with significant probable activities (Pa > 0.7) as immune-stimulant, anti-inflammatory, neuroprotective, antiproliferative, immunomodulator, and antineoplastic, among others. Moreover, in vitro assays exhibited that both IC and CW fractions presented angiotensin-converting enzyme-inhibitory (> 90%), chelating (> 79%), and antioxidant (ca. 22-57 cellular antioxidant activity units) activities. Our findings based on in silico and in vitro analyses suggest that L. casei CRL 431 and B. coagulans GBI-30 strains appear to be promising sources of postbiotics and may impart health benefits by their multifunctional properties.

New Insights into the Antimicrobial Properties of Hydrolysates and Peptide Fractions Derived from Chia Seed (Salvia hispanica L.)

Bioactive peptides derived from chia (Salvia hispanica) seed with antioxidant, antihypertensive, and anti-inflammatory activities have been well documented; however, few studies describe the antimicrobial properties of these peptides, which is of great interest not only in the prevention of food-borne diseases but also food spoilage. The aim of this study was to generate chia seed peptides using microwave-assisted hydrolysis with sequential (alcalase + flavourzyme) enzymes (AF-MW), fractionate them into 3-10 and < 3 kDa fractions, and evaluate their potential antimicrobial activity towards Escherichia coli, Salmonella enterica, and Listeria monocytogenes. Overall, the peptide fraction < 3 kDa showed higher antimicrobial activity than both chia seed hydrolysate and peptide fraction 3-10 kDa. Furthermore, the < 3 kDa fraction showed remarkable increase in membrane permeability of E. coli (71.49% crystal violet uptake) and L. monocytogenes (80.10% crystal violet uptake). These peptides caused a significant extension in the lag phase, decreases in the maximum growth, and growth rate in the bacteria and promoted multiple indentations (transmembrane tunnels), membrane wrinkling, and pronounced deformations in the integrity of the bacterial cell membranes. Finally, a select group of peptides in the AF-MW < 3 kDa fraction contained 16 sequences with cationic and hydrophobic character, with seven of them sharing the exact same sequence (GDVIAIR) and eight of them having the amino acid K as either N- or C-terminal or both. In conclusion, our results indicate that bioactive peptides obtained from chia seed proteins by microwave and enzymatic hydrolysis could be employed as antimicrobial agents in foods and therapeutic applications.

The effect of grape seed protein hydrolysate on the properties of stirred yogurt and viability of Lactobacillus casei in it

In this study, the effect of grape seed protein hydrolysate (GPH) on the physicochemical and sensory properties of stirred yogurt was evaluated. At first, the antioxidant properties and degree of hydrolysis (DH) of GPH were determined using the microbial protease enzymes (alcalase and flavourzyme), the results showed that alcalase enzyme can produce GPH with higher DH and antioxidant properties (p < .05). Also, increasing the hydrolysis time had a positive effect on these properties (p < .05). The DH, free radical scavenging DPPH, and ferric reducing power for GPH by alcalase at 30 min was 21.51%, 88.68%, and 0.33 μmol ferrous/ g, respectively. Therefore, this treatment was used for further experiments. In the next part, the mentioned GPH was added to the stirred yogurt with three concentrations (0.5, 1.5, and 1.5%) and physicochemical properties and viability of Lactobacillus casei and sensory properties were measured during 15 days of storage. The results showed that the GPH treatment had higher pH, viscosity, and texture firmness and less acidity and syneresis compared with the control sample (p < .05). Also, in these samples, the decreasing trend of L. casei viability was slower than the control treatment during the storage period (p < .05). In most parameters, better results were observed with increasing the concentration GPH and all the treatments were acceptable in terms of sensory properties. Therefore, by producing yogurt containing GPH, a new functional food can be provided for consumers of dairy products, which in addition to the desired taste, good nutritional properties can be also achieved from its consumption.

Hairless canary seeds (Phalaris canariensis L.) as a potential source of antioxidant, antihypertensive, antidiabetic, and antiobesity biopeptides

Rising consumer concerns with synthetic drugs to treat non-communicable diseases (NCDs) have promoted a shift towards using natural biological active constituents that offer similar health benefits. Hairless canary seed (Phalaris canariensis L) is an emerging crop traditionally used in Mexico to treat NCDs. Peptides liberated during simulated digestion of canary seed protein are believed to be responsible for their biological activity; however, no studies have shown the effect of controlled protein hydrolysis using commercial proteases on canary seed protein’s biological activity. Therefore, this study aimed to explore the in vitro antihypertensive, antidiabetic, and anti-obesity activity of canary seed peptides derived from proteolysis with Alcalase®. Protein fractions were primarily composed of prolamins (54.07 ± 1.8%), glutelins (32.19 ± 3.18%), globulins (5.97 ± 0.52%) and albumins (5.97 ± 0.52%). The < 3 kDa and 3–10 kDa peptide fractions showed the highest inhibition capacity (p < 0.05) towards angiotensin-converting enzyme (IC50= 0.028–0.032 mg/mL) lipase (IC50= 2.15–2.27 mg/mL), α-glucosidase (IC50= 0.82–1.15 mg/mL), and dipeptidyl-peptidase-IV (IC50= 1.27–1.60 mg/mL). Additionally, these peptide fractions showed high antioxidant activity against DPPH (134.22–150.66 μmol TE/mg) and ABTS (520.92–813.33 μmol TE/mg). These results provide an insight into the potential development of functional foods using commercial enzymatic hydrolysis of canary seed proteins for treating hypertension, type-2 diabetes, and obesity.

Production and processing of antioxidant bioactive peptides: A driving force for the functional food market

Recently, the demand for functional foods in the global market has increased rapidly due to the increasing occurrences of non-communicable diseases and technological advancement. Antioxidant peptides have been suggested as ingredients used to produce health-promoting foods. These peptides are encrypted from various food derived protein sources by chemical and enzymatic hydrolysis, and microbial fermentation. However, the industrial-scale production of antioxidant peptides is hampered by different problems such as high production cost, and low yield and bioactivity. Accordingly, novel processing technologies, such as high pressure, microwave and pulsed electric field, have been recently emerged to overcome the problems associated with the conventional hydrolysis methods. This particular review, therefore, discussed the current processing technologies used to produce antioxidant peptides. The review also suggested further perspectives that should be addressed in the future.

Advances on Food-Derived Peptidic Antioxidants-A Review

The oxidation process is considered to be the main reason behind human aging, human degenerative diseases and food quality degradation. Food-derived peptidic antioxidants (PAs) have wide sources and great activity, and have broad application prospects in removing excess reactive oxygen species in the body, anti-aging and preventing and treating diseases related to oxidative stress. On the other hand, PAs are expected to inhibit the lipid peroxidation of foods and increase the stability of the food system in the food industry. However, the production pathways and action mechanism of food-derived PAs are diverse, which makes it is difficult to evaluate the performance of PAs which is why the commercial application of PAs is still in its infancy. This article focuses on reviewing the preparation, purification, and characterization methods of food-derived PAs, and expounds the latest progress in performance evaluation and potential applications, in order to provide an effective reference for subsequent related research of PAs.

Impact of microwave processing on the secondary structure, in-vitro protein digestibility and allergenicity of shrimp (Litopenaeus vannamei) proteins

This study aimed to evaluate the effects of microwave processing (2.45 GHz, 1000 W, 75-125 °C, and 5-15 min) on the secondary structures, in-vitro protein digestibility, microstructural characteristics, and allergenicity of shrimp. SDS-PAGE analysis showed that the band intensity of tropomyosin reduced with the increase of processing temperatures and durations. The significant reduction in the allergenicity of tropomyosin was up to 75% when treated with microwave at 125 °C for 15 min. A significant reduction by 30-75% in the total soluble protein content, peptide content, and in-vitro protein digestibility of shrimp protein was observed. These changes mentioned above were strongly associated with the modification of the secondary structure of shrimp proteins, including the increase in β-sheets, and the loss in turns. Also, more microscopic holes, fragments, strips in treated samples were observed by scanning electron microscopy. Therefore, high-intensity microwave treatment showed great potential in reducing the allergenicity of shrimp.

Effects of ultrasonic, microwave, and combined ultrasonic-microwave pretreatments on the enzymatic hydrolysis process and protein hydrolysate properties obtained from Chinese sturgeon (Acipenser sinensis)

Degree of hydrolysis (DH), yield, amino acid profile, protein solubility, and antioxidant activity of Chinese sturgeon protein hydrolysates, as influenced by thermal pretreatment, ultrasonic (US), microwave (MW), and combined US-microwave pretreatments were investigated. Initially, the samples were subjected to thermal pretreatments in order to measure their effect on DH, which increased at 55°C. The DH recorded 7.63, 5.55, and 6.02% for US, MW, and combined US-MW pretreatment (US + MW), respectively, at the optimal time (8 min). The enzymatic hydrolysis (EN) of pretreated samples increased the DH to 19.41, 14.18, and 16.91% for US + EN, MW + EN, and US + MW + EN, respectively. The US + EN treatment was most effective for obtaining higher DH and yield, which were 19.41% and 18.62%, respectively. The use of US + EN also resulted in an increase in the percentage of molecular weights (≤1,000 Da), amino acid content and protein solubility, which reached 89.24, 80.08, and 98.58%, respectively. While, US + MW + EN pretreatment has achieved the highest antioxidant activities by IC₅₀ of 1,1-diphenyl-2-picrylhydrazyl and 2,2-Azinobis (3-ehtylbenzothiazoli- 6-sulfnic acid), which were 3.01 and 1.85 mg/ml, respectively, in addition to the reducing power assay, which was 0.528 at a protein concentration of 5 mg/ml. Therefore, US and combined US-MW techniques can play a promising role in the production of protein hydrolysates and the improvement of their antioxidant properties. PRACTICAL APPLICATIONS: Nowadays, interest in Chinese sturgeon production has increased as a promising source of protein and antioxidant peptides. The optimal thermal pretreatment can be used to enhance the degree of hydrolysis. The results indicated that the use of ultrasound as a pretreatment enhanced the degree of hydrolysis, which could be useful in the preparation of protein hydrolysate with higher yields. The use of combined US-MW significantly improved the antioxidant properties of the protein hydrolysate. The combined US-MW technique is a novel method for obtaining valuable peptides and protein hydrolysates that can be applied as antioxidant constituents in the food products.

High Hydrostatic Pressure-Assisted Enzymatic Hydrolysis Affect Mealworm Allergenic Proteins

Edible insects have garnered increased interest as alternative protein sources due to the world's growing population. However, the allergenicity of specific insect proteins is a major concern for both industry and consumers. This preliminary study investigated the capacity of high hydrostatic pressure (HHP) coupled to enzymatic hydrolysis by Alcalase^® or pepsin in order to improve the in vitro digestion of mealworm proteins, specifically allergenic proteins. Pressurization was applied as pretreatment before in vitro digestion or, simultaneously, during hydrolysis. The degree of hydrolysis was compared between the different treatments and a mass spectrometry-based proteomic method was used to determine the efficiency of allergenic protein hydrolysis. Only the Alcalase^® hydrolysis under pressure improved the degree of hydrolysis of mealworm proteins. Moreover, the in vitro digestion of the main allergenic proteins was increased by pressurization conditions that were specifically coupled to pepsin hydrolysis. Consequently, HHP-assisted enzymatic hydrolysis represents an alternative strategy to conventional hydrolysis for generating a large amount of peptide originating from allergenic mealworm proteins, and for lowering their immunoreactivity, for food, nutraceutical, and pharmaceutical applications.

Modifications of the Protein Characteristics of Pacaya Caused by Thermal Treatment: A Spectroscopic, Electrophoretic and Morphological Study

The inflorescences of Chamaedorea tepejilote Liebm. are consumed as food in Central America and southern Mexico but is an underutilized food because of its sensory characteristics, principally due to its bitter taste. However, the inflorescences of Chamaedorea tepejilote Liebm. are nutritionally promising due to their high protein content (approximately 25%). Protein isolates from pacaya were modified via three different thermal treatments to determine the effect of the treatments on the protein structures. Scanning electron microscopy indicated that the pacaya protein isolate particles had less rough and irregular surfaces with larger particle sizes due to an aggregation process when a thermal treatment was used compared to those when no thermal treatment was used. An increase in the intensity of the low molecular weight protein fractions (≤20 kDa) in the electrophoretic pattern of the proteins was observed, which was generated by the hydrolysis of the proteins by heat treatment. The modifications in the FT-IR spectra showed that thermal treatment of pacaya affected the secondary structure of its proteins, mainly when microwave treatment was used. Raman spectroscopy revealed that the α-helical structure was dominant in the proteins of pacaya and that thermal treatment increased the fraction of the β-sheet structure at the expense of the α-helical structure.

Potential role of natural bioactive peptides for development of cosmeceutical skin products

In recent years, consumers' demand for cosmeceutical products with protective and therapeutic functions derived from natural sources have caused this industry to search for alternative active ingredients. Bioactive peptides have a wide spectrum of bioactivities, which make them ideal candidates for development of these cosmeceutical products. In vitro studies have demonstrated that bioactive peptides (obtained as extracts, hydrolysates, and/or individual peptides) exhibit biological properties including antioxidant, antimicrobial, and anti-inflammatory activities, in addition to their properties of inhibiting aging-related enzymes such as elastase, collagenase, tyrosinase and hyaluronidase. Some studies report multifunctional bioactive peptides that can simultaneously affect, beneficially, multiple physiological pathways in the skin. Moreover, in vivo studies have revealed that topical application or consumption of bioactive peptides possess remarkable skin protection. These properties suggest that bioactive peptides may contribute in the improvement of skin health by providing specific physiological functions, even though the mechanisms underlying the protective effect have not been completely elucidated. This review provides an overview of in vitro, in silico and in vivo properties of bioactive peptides with potential use as functional ingredients in the cosmeceutical field. It also describes the possible mechanisms involved as well as opportunities and challenges associated with their application.

Production and In Vitro Gastrointestinal Digestion of Antioxidant Peptides from Enzymatic Hydrolysates of Sweet Potato Protein Affected by Pretreatment

Effects of ultrasonication, boiling, steaming, microwaving and autoclaving pretreatments on the production of sweet potato protein hydrolysates (SPPH) by single and combined Alcalase (ALC) and Protease (PRO) were investigated, as well as antioxidant activities of SPPH subjected to in vitro gastrointestinal digestion (GID). All pretreatments significantly increased the degree of hydrolysis (DH) and antioxidant activities of SPPH by ALC, PRO and ALC + PRO in the order of autoclaving > steaming, microwaving, boiling > ultrasonication (P < 0.05). GID significantly enhanced antioxidant activities and increased MW <3 kDa peptide fraction contents of all SPPH. Diverse peptides were identified as sporamin A, A precursor and sporamin B before and after GID from LC-QTOF-MS/MS analysis. Peptides with higher antioxidant amino acids of Trp, Tyr, Met, Cys, His and Phe were found after GID. There is a great potential application of SPPH as a novel food ingredient as a natural antioxidant.

Purification and identification of an antioxidant peptide from perilla seed (Perilla frutescens) meal protein hydrolysate

This study aimed to obtain antioxidant peptides from perilla seed meal (PSM), which is normally discarded as an industrial waste during seed oil extraction. PSM protein was hydrolyzed using trypsin and fractionated by ultrafiltration. Molecular weight fraction (<3 kDa) with the highest antioxidant activity was purified using prep-HPLC and analytical HPLC. The purification fold of the peptide (fraction V) obtained from PSM protein hydrolysate on DPPH radical scavenging activity, ABTS radical scavenging activity, and reducing power was 1.79-, 1.59-, and 1.81-fold, respectively, after the three-step purification procedure. The sequence of the purified peptide from fraction V that exhibited free radical scavenging activity and reducing power was identified as Ile-Ser-Pro-Arg-Ile-Leu-Ser-Tyr-Asn-Leu-Arg (1,330.77 Da). These results demonstrate that PSM protein, a by-product from the oil seed extraction, can be used as a source of natural antioxidant peptides for food and/or nutraceutical applications.

Effects of different pretreatments and proteases on recovery, umami taste compound contents and antioxidant potentials of Labeo rohita head protein hydrolysates

Effects of the pretreatments namely heating, microwave (MW), and ultrasound (US), followed by the enzymatic hydrolysis using different proteases (flavourzyme, neutrase, and protamex) on the protein recovery, umami taste compound content, and antioxidant activities of the Labeo rohita head (LRH) protein hydrolysate was investigated. US and MW pretreatments increased the protein recovery, MSG-like amino acid and flavour 5'-nucleotide contents, equivalent umami concentration (EUC) and antioxidant activities of LRH protein hydrolysates significantly (p < 0.05). The type of enzyme influenced the protein recovery and EUC significantly but did not influence the flavour 5'-nucleotide content of LRH protein hydrolysate (p > 0.05). The highest recovery yield of LRH protein hydrolysate (69.75%) was obtained with the MW pretreatment followed by the protamex hydrolysis, while the highest EUC (41.82 g monosodium glutamate (MSG)/kg) was yielded with the combination of the US pretreatment and the flavourzyme hydrolysis. These results indicate that US and MW pretreatments can help to enhance the recovery yield, umami taste compound content and antioxidant activities of the LRH protein hydrolysate.

Combined microwave processing and enzymatic proteolysis of bovine whey proteins: the impact on bovine β-lactoglobulin allergenicity

The main aim of this study was to develop a continuous microwave treatment system of whey proteins and then apply this process at 37 °C, 50 °C, 65 °C and 70 °C to achieve pepsinolysis and produce extensively hydrolysed bovine whey protein hydrolysates with low allergenic properties. The microwave process was compared to a conventional thermal treatment with similar temperature set points. Both processes were deeply analysed in terms of the thermal kinetics and operating conditions. The pepsin hydrolysates obtained by the continuous microwave treatment and conventional heating were characterized by SDS-PAGE and RP-HPLC. The allergenicity of the whey protein hydrolysates was explored using a human IgE sensitized rat basophil leukaemia cell assay. The results indicate that extensively hydrolysed whey protein hydrolysates were obtained by microwave only at 65 °C and in a shorter time compared with the conventional thermal treatment. In the same temperature conditions under conventional heating, β-lactoglobulin was resistant to pepsinolysis, and 37% of it remained intact. As demonstrated by an in vitro degranulation assay using specific human IgE-sensitized rat basophils, the extensively hydrolysed whey protein obtained by microwave showed maximum degranulation values of 6.53% compared to those of the native whey protein isolate (45.97%) and hence elicited no more allergenic reactions in basophils. This work emphasizes the potential industrial use of microwave heating specific to milk protein processing to reduce their allergenicity and improve their end-use properties.

Marine Waste Utilization as a Source of Functional and Health Compounds

Consumer demand for convenience has led to large quantities of seafood being value-added processed before marketing, resulting in large amounts of marine by-products being generated by processing industries. Several bioconversion processes have been proposed to transform some of these by-products. In addition to their relatively low value conventional use as animal feed and fertilizers, several investigations have been reported that have demonstrated the potential to add value to viscera, heads, skins, fins, trimmings, and crab and shrimp shells by extraction of lipids, bioactive peptides, enzymes, and other functional proteins and chitin that can be used in food and pharmaceutical applications. This chapter is focused on reviewing the opportunities for utilization of these marine by-products. The chapter discusses the various products and bioactive compounds that can be obtained from seafood waste and describes various methods that can be used to produce these products with the aim of highlighting opportunities to add value to these marine waste streams.