Fish protein hydrolysates: Proximate composition,amino acid composition,antioxidant activities and applications: A review

The fish processing industry produces more than 60% by-products as waste, which includes skin, head, viscera, trimmings, liver, frames, bones, and roes. These by-product wastes contain good amount of protein rich material that are normally processed into low market-value products, such as animal feed, fish meal and fertilizer. In view of utilizing these fish industry wastes, and for increasing the value to several underutilised fish species, protein hydrolysates from fish proteins are being prepared by several researchers all over the world. Fish protein hydrolysates are breakdown products of enzymatic conversion of fish proteins into smaller peptides, which normally contain 2–20 amino acids. In recent years, fish protein hydrolysates have attracted much attention of food biotechnologists due to the availability of large quantities of raw material for the process, and presence of high protein content with good amino acid balance and bioactive peptides (antioxidant, antihypertensive, immunomodulatory and antimicrobial peptides).     

Valorisation of tuna viscera by endogenous enzymatic treatment

Fish processing industry generates a considerable amount of by-products which represent an environmental problem. Only a small portion of these residues is used for the production of low marketable products. Therefore, industrially scalable processes yielding value-added products would be highly desirable. Different to others studies, this work deals with potential valorisation of bullet tuna (Auxis rochei) viscera using its endogenous enzymes without previous separation stage for the production of bioactive hydrolysates. Functional and bioactive properties of hydrolysates produced at different degree of hydrolysis (DH 3%, 6% and 9%) were evaluated. The endogenous enzyme hydrolysates (EH) obtained by the proposed low cost treatment were compared with hydrolysates produced with a well-known commercial enzyme: subtilisin. Regarding functional properties, EH presented similar or even better solubility, emulsifying and oil binding capacities than subtilisin hydrolysate (SH). EH also showed very interesting antioxidative properties, particularly metal reducing and radical scavenging activity. Additionally, the ACE inhibitory activity of EH at low degree of hydrolysis was comparable to SH. According to these results, bullet tuna viscera protein can be value-added by endogenous enzyme hydrolysis.     

Valorisation of protein hydrolysates from animal by-products: perspectives on bitter taste and debittering methods: a review

Conversion of animal by-products to high value-added food ingredients is one of the top trends in the slaughter industry. Enzymatic hydrolysis of animal by-products can generate protein hydrolysates, which provides an opportunity for effective utilisation. However, bitterness of protein hydrolysate is a major undesirable aspect for various applications. In this review, the current knowledge on protein hydrolysates from animal by-products is briefly reviewed. The structural features of bitter peptides and bitter taste receptors are summarised. Moreover, the potential approaches for debittering protein hydrolysates are highlighted, including exopeptidase treatment, Maillard reaction, plastein reaction and encapsulation. In addition, the current debittering strategies and challenges are also discussed. This article presents some opportunities to utilise protein hydrolysates from animal by-products and their debittering methods.     

动物血浆蛋白水解物功能及应用研究进展

动物血液是动物屠宰加工的主要副产物之一,蛋白质含量丰富、营养价值高,其中血浆蛋白作为重要的蛋白原料,可用于动物饲料和食品加工。研究表明,血浆蛋白经酶处理得到由小肽和氨基酸组成的水解物,更易被机体消化吸收,同时表现出抗氧化、抑制血管紧张素转化酶活性、减毒等功能特性,可作为潜在的营养补充剂、食品添加剂和营养保健品。本文对血浆蛋白水解物的酶解条件、特性以及应用进行综述,以期为动物血浆蛋白水解物的研究和应用提供参考。     

Functions,applications and production of protein hydrolysates from fish processing co-products (FPCP)

Considerable amounts of fish processing co-products (FPCP) are generated which currently impose a cost burden on the seafood industry in terms of waste disposal, with little benefit generated. The demand for the sustainable use of FPCP has led to the development of processes for the recovery and hydrolysis of proteins, the assessment of their functionalities, and application into different products. The aim of this review is to critically analyze the-state-of-the-art on the functions, applications and production processes of FPCP protein hydrolysates, and identify the key research trends and future research directions that will maximize the economic and environmental benefits for the fish processing industry. FPCP protein hydrolysates have been found to possess desirable physicochemical properties (e.g. emulsifying, foaming, oil and water binding capacities) and many interesting bio-activities (anti-oxidative, anti-hypertensive, anti-microbial and anti-anemia) with potential applications in food, nutritional and pharmaceutical products. Chemical hydrolysis has been the most common process for the production of crude FPCP protein hydrolysates, though with little ability to control product quality. The enzymatic hydrolysis process has emerged recently as the process of choice due to its mild reaction conditions, superior product quality and functionality. The enzymatic processes have been demonstrated at the laboratory scale, but not as in full industrial-scale operation, probably due to the high costs of the enzyme. Advanced cost effective processing technologies need to be developed for the production of high quality FPCP protein hydrolysates that possess specific functionalities for specific product applications. Protein hydrolysates with defined molecular weight ranges, tailor-made for superior functionalities are in high demand. With the discovery of new functions and applications for FPCP protein hydrolysates by refining the traditionally crude product mixture, the fish processing industry can be empowered with advanced value-added processing technology and next generation functional products to successfully turn the “cost center” for the removal of waste into a “profit center” for business growth.     

Antihypertensive peptides of animal origin: A review

Many bioactive peptides trigger certain useful antihypertensive activities in the living body system and there is a mounting worldwide interest in the therapeutic potential of these bioactive peptides for exploitation in vivo against the hypertension. Studies suggest the antihypertensive properties for many bioactive peptides of animal origin with underlying mechanisms ranging from inhibition of angiotensin-converting enzyme to additional mechanisms to lower blood pressure such as opioid-like activities and mineral-binding and antithrombotic properties. Antihypertensive peptides are the most extensively studied of all the bioactivities induced by food protein hydrolysates, highlighting their importance in human health and disease prevention and treatment. There exist enormous opportunities for the production of novel peptide-based products in biopharmaceutical manufacturing industries for the treatment, prevention, and mitigation of hypertension. Numerous products have already struck on the global market and many more are in process. This article focuses on antihypertensive peptides identified in the meat, fish, blood, milk, dairy products, and egg and their probable application as novel ingredients in the development of functional food products as dietary treatment of hypertension.     

Functional and bioactive properties of fish protein hydolysates and peptides: A comprehensive review

Global fish processing industries dispose of fish wastes that account for more than 60% of processed fish biomass. In lieu of environmental pollution and disposal problems, these wastes are used to produce fish silage, fishmeal and sauce. They are also utilized for the production of value added products such as proteins, hydrolysates, bioactive peptides, collagen and gelatin. Research on the production of fish protein hydroysates (FPHs) presently focuses on maximizing the industrial potential of fish wastes. Since bioactive peptides containing amino acids hold properties of great interest, this paper reviews current research on the functional and bioactive properties of FPHs with an additional focus on gaps between fish and other hydrolysates, as well as current and future trends for the productive utilization of FPHs.     

Fish protein hydrolysates: production, biochemical, and functional properties

Considerable amounts of fish processing byproducts are discarded each year. By developing enzyme technologies for protein recovery and modification, production of a broad spectrum of food ingredients and industrial products may be possible. Hydrolyzed vegetable and milk proteins are widely used food ingredients. There are few hydrolyzed fish protein foods with the exception of East Asian condiments and sauces. This review describes various manufacturing techniques for fish protein hydrolysates using acid, base, endogenous enzymes, and added bacterial or digestive proteases. The chemical and biochemical characteristics of hydrolyzed fish proteins are discussed. In addition, functional properties of fish protein hydrolysates are described, including solubility, water-holding capacity, emulsification, and foam-forming ability. Possible applications of fish protein hydrolysates in food systems are provided, and comparison with other food protein hydrolysates where pertinent.     

鱼皮及其加工制品的研究进展与应用

近年来,随着鱼类加工产量的增加,其加工产生的副产物也随之增多。鱼皮作为鱼类加工副产物之一,含有丰富的蛋白质、氨基酸、矿物质和不饱和脂肪酸等,具有较强的加工潜力,但目前能够将其进行加工的企业较少,通常是将鱼皮直接丢弃,这不仅造成大量的浪费,而且污染环境。本文梳理了鱼皮中的营养成分、胶原蛋白的提取方法以及已有的鱼皮加工制品,对鱼皮在食品、功能性产品、化妆品、和医疗和服饰领域等不同方面的研究现状及应用概况进行综述,提出现阶段鱼皮加工应用领域中所存在的问题,并对未来鱼皮加工产品的走向和发展进行展望,以期为鱼类加工副产物的高值化利用提供参考依据,对优化和拓宽我国水产品副产物的研究领域和提升国家经济效益具有重要意义。     

Fish meal in animal feed and human exposure to persistent bioaccumulative and toxic substances

Persistent and bioaccumulative toxic substances (PBTSs) that end up in fish are health hazards and the object of fish-consumption advisories. Some of these substances are present as extraneous contaminants, e.g., man-made lipophilic pollutants such as organohalogen pollutants, and others such as monomethyl mercury can be considered naturally occurring. Omnivores (e.g., poultry and swine) and especially ruminants that are fed contaminated fish meal can pass monomethyl mercury and organohalogen pollutants to eggs, meat, and dairy products. Differences in fish meal PBTS profiles and farm animal (e.g., poultry, swine, cattle, and farmed fish) physiology modulate PBTSs in animal products. Fish-consumption advisories issued to protect human health do not extend to fish by-products fed to farmed animals. Animals (especially farmed fish) that are fed fish meal can bioconcentrate monomethyl mercury in protein matrices, and organohalogen pollutants can be passed on in the fat components of derived foods. Policies to decrease exposure to monomethyl mercury and organohalogen pollutants must consider farming practices that use fish by-products. A risk assessment of toxic contaminants in fish meal may indicate that food safety objectives must consider the human health impact of foods derived from animals fed contaminated meal.     

鱼副产物蛋白水解物生物活性及应用研究进展

鱼副产物蛋白质含量丰富、营养价值高,但综合利用程度较低,不仅会造成资源浪费,还会导致环境问题。研究表明,鱼副产物经蛋白酶处理能够得到小分子肽类水解物,其表现出抗氧化活性、抗冻性能、抗菌性、降血压等功能活性,可作为潜在的营养补充剂和食品添加剂。本文综述了鱼副产物蛋白水解物的制备、生物活性及应用前景,总结了生产中存在的问题及发展趋势,旨在为鱼副产物蛋白水解物的研究和应用提供参考。     

Peptides: Production,bioactivity, functionality,and applications

ABSTRACT

Production of peptides with various effects from proteins of different sources continues to receive academic attention. Researchers of different disciplines are putting increasing efforts to produce bioactive and functional peptides from different sources such as plants, animals, and food industry by-products. The aim of this review is to introduce production methods of hydrolysates and peptides and provide a comprehensive overview of their bioactivity in terms of their effects on immune, cardiovascular, nervous, and gastrointestinal systems. Moreover, functional and antioxidant properties of hydrolysates and isolated peptides are reviewed. Finally, industrial and commercial applications of bioactive peptides including their use in nutrition and production of pharmaceuticals and nutraceuticals are discussed.     

Bioactive protein hydrolysates in the functional food ingredient industry: Overcoming current challenges

Meat proteins and associated by-products can be used as a source of bioactive hydrolysates and peptides with potential for use as functional food ingredients. Functional foods are foods that have a potentially positive effect on health, beyond basic nutrition. Numerous bioactive peptides, including angiotensin-I-converting enzyme (ACE-I, EC 3.4.15.1) and dipeptidyl peptidase-IV (DPP-IV, EC 3.4.14.5) inhibitors, have been generated from meat by-product proteins to date. However, in order to use and commercialize bioactive hydrolysates and peptides as food ingredients, a number of significant challenges must first be overcome. This article gives an overview of the current state-of-the-art of meat-derived bioactive hydrolysate and peptide uses in the food industry. It also reviews frequent challenges faced when developing biologically active hydrolysates and peptides as food ingredients. These challenges include, but are not limited to, high production costs, negative sensory attributes in end products, taste modifications of carrier food products and compliance with, for example, the European Food Safety Authority (EFSA), the Food and Drug Administration (FDA), and other regulatory bodies in China, or Japan, as well as potential toxicity or allergenicity. We suggest strategies that may assist in overcoming these challenges, focusing on those that may be used to improve the taste attributes of the end products.     

Bioactive peptides from marine processing waste and shellfish: A review

Marine organisms such as fish and shellfish are rich sources of structurally diverse bioactive nitrogenous components. Based on emerging evidence of potential health benefits, these components show significant promise as functional food ingredients. Activities including antihypertensive, antioxidant, anti-microbial, anti-coagulant, anti-diabetic, anti-cancer, immunostimulatory, calcium-binding, hypocholesteremic and appetite suppression have been reported. Fish and shellfish waste components contain significant levels of high quality protein (10–23% (w/w)) which represents a source for biofunctional peptide mining. This review summarises the protein-derived bioactive peptides identified in marine processing waste, molluscs and crustaceans. Moreover, it highlights the potential of proteins derived from these marine organisms as substrates for the generation of biofunctional peptides. It outlines current technologies used in the production, fractionation and purification of marine protein-derived peptides and lists some commercially available products containing marine derived bioactive protein hydrolysates and peptides. Finally, bioactive proteins, non-protein peptides and amino acids found in fish and shellfish are briefly discussed.     

Physicochemical and functional characteristics of proteins treated by a pH-shift process: a review

Advanced structures of food proteins are maintained by many forces such as hydrophobic activities, electrostatic interaction, and disulphide bond interaction, which can affect their functional characteristics to a certain extent. Therefore, many approaches have been utilised to improve functional characteristics of food proteins. pH-shift process refers to the method that food proteins are treated under extreme alkaline or acid conditions followed by adjusting pH to isoelectric point or neutral pH. Many studies have showed that pH-shift process can significantly affect the functional characteristics of food proteins, for example emulsifying activities, forming property, solubility and water/oil adsorption ability. pH-shift process has been utilised to recover protein isolates from many sources including fish, fish by-products, meat processing products. Many researches have indicated that the functional and physicochemical characteristics of recovered protein isolates are significantly influenced by pH-shift process. In this paper, the latest studies regarding the functional and physicochemical characteristics of proteins treated or recovered through pH-shift process, and potential applications of obtained protein isolates in the production of the hydrolysates or used as a delivery system were reviewed.     

Nutritional,functional and biological properties of insect proteins: Processes for obtaining,consumption and future challenges

BackgroundConsuming insects as an alternative protein source is considered a future trend and a viable strategy that could potentially contribute to global food security. Insects are a non-conventional source of protein, either for human consumption directly or indirectly as a component in recomposed foods or added to feedstock mixtures. Moreover, these proteins have demonstrated a broad range of applications as peptides with antihypertensive, antimicrobial and antioxidant properties. However, aspects such as food safety and processing of these proteins need further studies for their elucidation and optimization.Scope and approachIn this review, aspects of nutritional value and risks of insect consumption are reported. Additionally, conventional processing techniques and recent advances in insect protein extraction and production are presented. The application of bioactive peptides obtained from insect protein hydrolysates is reported, focusing on their potential antihypertensive, antimicrobial and antioxidant properties.Key findings and conclusionsInsect proteins have great advantages in terms of nutritional value, total protein level and amino acid profile. However, some safety concerns must be taken into consideration in large-scale production. The conventional processing of insects proteins is very particular, depending on several aspects such as species, larval stage, and cultivation, among others. Nonetheless, recent advances in insect protein production via enzymatic hydrolysis and heterologous expression have shown a promising technology for the study and exploitation of their bioactive properties, such as the antimicrobial, antioxidant and antihypertensive (inhibition of ACE) activity of insect peptides.     

Olive by-products for functional and food applications: Challenging opportunities to face environmental constraints

This comprehensive review points out the major developments on the recovery of bioactive compounds of olive by-products, intending innovative food applications and enhanced technological functions. Nutritional and sensorial factors influencing consumers' acceptance are also discussed. Besides being an economic burden for producers, olive oil by-products also represent a severe environmental problem. Simultaneously, these are rich in bioactive compounds, which are remarkable added-value ingredients for other industries. New applications have been focused in ameliorating the food nutritional profile, replacing or improving technological properties/functions of food additives, and extending food products shelf life. Eco-friendly food packaging is also a promissory application field. The improvement of nutritional functionality and sensory quality of enriched food is another challenging task. Despite the large chemical characterization of olive products and olive oil processing by-products, further research is still needed to fully understand the potential of this valuable raw material.Industrial relevanceHigh added-value ingredients can be obtained by recovering bioactive compounds from olive by-products. Those can be used by food industry to improve food product nutritional profile and/or with a technological functionality. This review presents food applications developed with ingredients and bioactive compounds derived from olive processing by-products. It aims to be useful for food industries and other agro-industrial stakeholders in order to encourage and expand the utilization of olive by-products in the development of innovative food products.     

Bioactive peptides derived from milk proteins and their health beneficial potentials: an update

It has been well recognized that dietary proteins provide a rich source of biologically active peptides. Today, milk proteins are considered the most important source of bioactive peptides and an increasing number of bioactive peptides have been identified in milk protein hydrolysates and fermented dairy products. Bioactive peptides derived from milk proteins offer a promising approach for the promotion of health by means of a tailored diet and provide interesting opportunities to the dairy industry for expansion of its field of operation. The potential health benefits of milk protein-derived peptides have been a subject of growing commercial interest in the context of health-promoting functional foods. Hence, these peptides are being incorporated in the form of ingredients in functional and novel foods, dietary supplements and even pharmaceuticals with the purpose of delivering specific health benefits.     

Innovations in value-addition of edible meat by-products

While muscle foods are the more commonly consumed portion of an animal, meat by-products such as the entrails and internal organs are also widely consumed. Considered high-priced delicacies or waste material to be tossed away, the use and value of offal-edible and inedible meat by-products depend entirely on the culture and country in question. The skin, blood, bones, meat trimmings, fatty tissues, horns, hoofs, feet, skull, and internal organs of harvested animals comprise a wide variety of products including human or pet food or processed materials in animal feed, fertilizer, or fuel. Industry is using science and innovation to add value to animal by-products far beyond its usual profitability. Regardless of the final product's destination, it is still necessary to employ the most up-to-date and effective tools to analyze these products for nutritional properties, to search for key active molecules in nutrition like bioactive peptides, food safety (antimicrobial peptides), medicine, cosmetics or other fields, to develop new technological applications and to continue innovation towards advanced value-addition of meat by-products.     

Utilization of Fish Processing By-Products in the Gelatin Industry

Since the bovine spongiform encephalopathy crisis, there has been a growing interest for finding an alternative source of raw materials for gelatin production. Gelatin produced from fish processing by-products is a potential alternative to mammalian gelatin. Fish processing generates solid wastes that can be as high as 50–80% of the original raw material. These wastes are an excellent raw material for preparation of high protein foods. About 30% of the wastes consists of skin and bone with a high collagen content. Fish gelatin can be obtained by hydrolysis of collagen the principal protein found in skin and bone. Fish skin and bone gelatin can be prepared with bloom strength similar to that obtained from mammalian sources. Fish gelatin has numerous applications, particularly, in the food, pharmaceutical, and photographic industries due to its unique chemical and physical properties. This review presents how fish processing by-products can be utilized in the manufacture of gelatin.