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.     

Peptides Derived from Foods as Supportive Diet Components in the Prevention of Metabolic Syndrome

Metabolic syndrome (MSyn) includes physiological, biochemical, clinical, and metabolic abnormalities, leading to an increase in health problems like obesity, dyslipidemia, cardiovascular diseases, and diabetes, which contribute to an increase in mortality rate. One of the main factors having a key impact on our health is the food we consume. Thus, scientists work towards the discovery of novel bioactive compounds with therapeutic potential to address MSyn. According to scientific reports, peptides derived from food proteins exhibit bioactivities important for the prevention of MSyn diseases; that is, they regulate blood pressure and glycemia; reduce cholesterol level and body mass; and scavenge free radicals. The aim of this review is to study the potential role of peptides in the prevention of MSyn. Particularly peptides which exhibit the following activities: antihypertensive [angiotensin‐converting enzyme (ACE) inhibition (EC 3.4.15.1)], antidiabetic [dipeptidyl peptidase IV (DPP‐IV) (EC 3.4.14.5)/α‐glucosidase (EC 3.2.1.20)/α‐amylase (EC 3.2.1.1) inhibition)], cholesterol level reduction, antioxidative, and obesity prevention, were studied. If possible, special attention is paid in the review to the bioactivities of peptides that were measured in vivo. Some examples of peptides showing dual or multiple action against MSyn targets are presented. Moreover, using the database of bioactive peptide sequences (BIOPEP) we made a list of peptides serving simultaneous functions in counteracting MSyn dysfunctions. Such an approach may simplify the discovery of MSyn preventive peptides, as well as highlight some of them as potent bioactive ingredients that may be incorporated into foods. Moreover, the research strategy involving the in silico and in vitro/in vivo methodologies may be useful in the production of food protein hydrolysates supporting the treatment of MSyn dysfunctions.     

Milk-derived bioactive peptides: From science to applications

Milk proteins have received increasing attention as potential ingredients of health-promoting functional foods targeted at diet-related chronic diseases, such as cardiovascular disease, diabetes type two and obesity. To this end, growing interest has been focused on physiologically active peptides derived from milk proteins. These peptides are inactive within the sequence of the parent protein molecule and can be liberated by gastrointestinal digestion of milk, fermentation of milk with proteolytic starter cultures or hydrolysis by proteolytic enzymes. Milk protein-derived peptides have been shown under in vitro and in vivo conditions to exert a number of activities affecting the digestive, endocrine, cardiovascular, immune and nervous systems. A great variety of naturally formed bioactive peptides have been found in fermented dairy products, such as yoghurt, sour milk and cheese. Recently, industrial-scale technologies suitable for the industrial production of bioactive milk peptides have been developed. In addition, a few commercial food products supplemented with milk protein-derived bioactive peptides have been launched on limited markets. Some of these products carry clinically documented benefits, in particular for reduction of mild hypertension. The multifunctional properties of milk peptides appear to offer considerable potential for the development of many similar products in the near future.     

Marine food-derived functional ingredients as potential antioxidants in the food industry: An overview

Recently, a great deal of interest has been developed by the consumers towards natural bioactive compounds as functional ingredients in the food products due to their various health beneficial effects. Hence, it can be suggested that antioxidative functional ingredients from marine foods and their by-products are alternative sources for synthetic ingredients that can contribute to a consumer's well-being, as a part of nutraceuticals and functional foods. This contribution presents an overview of the marine food-derived antioxidants such as bioactive peptides, chitooligosaccharide derivatives, sulfated polysaccharides, phlorotannins and carotenoids with the potential utilization in the food industry.     

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.     

Food protein functionality: A comprehensive approach

Food protein functionality has classically been viewed from the perspective of how single molecules or protein ingredients function in solutions and form simple colloidal structures. Based on this approach, tests on protein solutions are used to produce values for solubility, thermal stability, gelation, emulsifying, foaming, fat binding and water binding to name a few. While this approach is beneficial in understanding the properties of specific proteins and ingredients, it is somewhat restricted in predicting performance in real foods where the complexities of ingredients and processing operations have a significant affect on the colloidal structures and therefore overall properties of the final food product. In addition, focusing on proteins as just biopolymers used to create food structures ignores the biological functions of proteins in the diet. These can be beneficial, as in providing amino acids for protein synthesis or bioactive peptides, or these can be detrimental, as in causing a food allergic response. This review will focus on integrating the colloidal/polymer and biological aspects of protein functionality. This will be done using foams and gels to illustrate colloidal/polymer aspects and bioactive peptides and allergenicity to demonstrate biological function.     

Healthier meat products as functional foods

A promising approach to improving health care would be to produce a healthier food supply as a preventive health care strategy. The food supply could be improved by producing functional foods that have nutritional profiles that are healthier than conventional products. However, production of functional foods is not always easily accomplished since they must also taste good, be convenient and reasonably priced so that consumers will regularly purchase and use the products. Meats have great potential for delivering important nutrients such as fatty acids, minerals, dietary fiber, antioxidants and bioactive peptides into the diet. However, to produce successful products with these ingredients, technologies must be developed to increase their stability and decrease their flavor impact on muscle foods. In addition, many regulatory hurdles must be overcome for the commercial production of meats with added nutrients. These include redefinition of standard of identities and policies that allow front of the package nutritional claims. Without these regulatory changes, production of healthier meat products won't become a reality since these products would not have a competitive advantage over unfortified meats.     

Enzymatic Production,Bioactivity, and Bitterness of Chickpea (Cicer arietinum) Peptides

Chickpeas are inexpensive, protein rich (approximately 20% dry mass) pulses available worldwide whose consumption has been correlated with positive health outcomes. Dietary peptides are important molecules derived from dietary proteins, but a comprehensive analysis of the peptides that can be produced from chickpea proteins is missing in the literature. This review provides information from the past 20 years on the enzymatic production of peptides from chickpea proteins, the reported bioactivities of chickpea protein hydrolysates and peptides, and the potential bitterness of chickpea peptides in food products. Chickpea peptides have been enzymatically produced with pepsin, trypsin, chymotrypsin, alcalase, flavorzyme, and papain either alone or in combination, but the sequences of many of the peptides in chickpea protein hydrolysates remain unknown. In addition, a theoretical hydrolysis of chickpea legumin by stem bromelain and ficin was performed by the authors to highlight the potential use of these enzymes to produce bioactive chickpea peptides. Antioxidant activity, hypocholesterolemic, and angiotensin 1‐converting enzyme inhibition are the most studied bioactivities of chickpea protein hydrolysates and peptides, but anticarcinogenic, antimicrobial, and anti‐inflammatory effects have also been reported for chickpea protein hydrolysates and peptides. Chickpea bioactive peptides are not currently commercialized, but their bitterness could be a major impediment to their incorporation in food products. Use of flavorzyme in the production of chickpea protein hydrolysates has been proposed to decrease their bitterness. Future research should focus on the optimization of chickpea bioactive peptide enzymatic production, studying the bioactivity of chickpea peptides in humans, and systematically analyzing chickpea peptide bitterness.     

Hierarchical mesoporous silica materials for separation of functional food ingredients — A review

Recently developed mesoporous silica materials are proposed as adsorbents for the separation of food bioactive molecules, due to their narrow pore size distributions and high surface area. These materials can be synthesised with a variety of porous architectures with uniform pore sizes in the mesoporous range, making them attractive candidates for adsorption of biomacromolecules. Research on these materials to date has largely focused on their synthesis, characterisation and applications in catalysis. However, recent developments in the bioadsorption ability and capacity as well as the aqueous stability of mesoporous materials demonstrate their potential as adsorbents for separations in the food industry. This paper reviews the research in this area and identifies the challenges remaining for the application of these materials in food based separations.Industrial relevanceThe increasing demand for health-promoting foods is a key driver for the development of highly selective, cost-effective separation technologies for food bioactive molecules. Separation and purification stages in industrial biotechnology processes can account for up to 70% of the capital and operating costs. A significant portion of the functional food market is devoted to dairy functional foods and ingredients, as milk and whey provide rich sources of bioactive proteins and peptides with a variety of biological and nutritional properties. Hence this paper focuses upon the potential for use of hierarchical mesoporous silica materials for separation of functional food ingredients, taking dairy streams as a representative example.     

Hypocholesterolaemic and antioxidant activities of chickpea (Cicer arietinum L.) protein hydrolysates

BACKGROUND: Some dietary proteins possess biological properties which make them potential ingredients of functional or health‐promoting foods. Many of these properties are attributed to bioactive peptides that can be released by controlled hydrolysis using exogenous proteases. The aim of this work was to test the improvement of hypocholesterolaemic and antioxidant activities of chickpea protein isolate by means of hydrolysis with alcalase and flavourzyme. RESULTS: All hydrolysates tested exhibited better hypocholesterolaemic activity when compared with chickpea protein isolate. The highest cholesterol micellar solubility inhibition (50%) was found after 60 min of treatment with alcalase followed by 30 min of hydrolysis with flavourzyme. To test antioxidant activity of chickpea proteins three methods were used: β‐carotene bleaching method, reducing power and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging effect since antioxidant activity of protein hydrolysates may not be attributed to a single mechanism. Chickpea hydrolysates showed better antioxidant activity in all assays, especially reducing power and DPPH scavenging effect than chickpea protein isolate. CONCLUSION: The results of this study showed the good potential of chickpea protein hydrolysates as bioactive ingredients. The highest bioactive properties could be obtained by selecting the type of proteases and the hydrolysis time. Copyright © 2012 Society of Chemical Industry     

茴香种子蛋白质水解物和肽的抗氧化和蛋白质保护潜力

茴香种子是一种可食用的香料,经常用于增进各种烹饪的香气和味道,并且因其药用价值而在不同文化中被珍藏。之前的研究报告提及了与茴香种子相关的各种生物活性。然而,对于来自茴香种子的水解蛋白质知之甚少。在本文中,作者从茴香种子中分离出总蛋白质,然后使用四种不同的蛋白酶进行酶水解。本文中也报道了水解度,pH和温度曲线。在ABTS自由基清除测定的指引下,作者使用离心过滤,C18反相和强阳离子交换(SCX)来进一步分离碱性蛋白酶消化的蛋白质水解物。与粗水解物相比,纯化水解物的自由基清除潜力增强了4.5倍。通过肽测序进一步分析纯化的SCX级分,本文也鉴定出两个肽序列,其范围为6～8个氨基酸。紧接着,文中也报道了使用白蛋白变性抑制试验来测试茴香肽的蛋白质保护潜力,其中一种茴香肽(EDVDFR)更被测出与纯谷胱甘肽(GSH)相当的EC50值。总要言之,茴香种子衍生的蛋白质水解物和茴香肽有潜力被进一步开发成促进健康的补充剂或作为食品添加剂用于保存富含蛋白质的食物。     

Characteristic Property of Low Bitterness in Protein Hydrolysates by a Novel Soybean Protease D3

ABSTRACT:  Enzymatic hydrolysis is 1 means of improving the functional properties of food protein; however, in most cases, bitter peptides are generated by such treatment, and the resulting product is therefore not acceptable as a food ingredient. We have already reported a novel cysteine protease, D3, purified from germinating soybean cotyledons. Because of its substrate specificities, most hydrophobic amino acid residues in the hydrolysate are presumed not to be located at the peptide termini. It was therefore expected that protein hydrolysate by protease D3 would taste less bitter than other enzymatic hydrolysates. The objective of this study was to demonstrate the low bitterness of protein hydrolysates by protease D3. For that purpose, soy protein and casein hydrolysates were prepared with treatment of protease D3, subtilisin, pepsin, trypsin, and thermolysin, respectively. The bitterness of these hydrolysates was evaluated by measuring points of subjective equality (PSE). The PSE value demonstrated that the protein hydrolysates by protease D3 were significantly less bitter than the other enzymatic hydrolysates, indicating that the products had a taste mild enough to be acceptable as a less-bitter peptide food ingredient. These results suggested that a prominent feature of protease D3 was its capacity to produce less-bitter peptides. Therefore, it is thought that protease D3 could be applied to produce protein hydrolysates for use as ingredients in a variety of food products.     

Parameters for the evaluation of the thermal damage and nutraceutical potential of lupin-based ingredients and food products

Foods based on sweet lupin proteins are gaining attention from industry and consumers because of their possible role in the prevention of cardiovascular disease. When promoting lupin-based foods for inclusion in a daily diet, the thermal damage suffered during processing is of relevance to the bioactive and nutritional quality of the food product. N-(2-furoylmethyl)-L-lysine (furosine) quantification demonstrates that currently available sweet lupin protein isolates have a thermal damage comparable to or lower than other traditional food ingredients, and are a good source of lysine in non-dairy products. In lupin-based foods claiming to have cholesterol-lowering potential, shotgun proteomics offers itself as a fast and effective screening method for assessing the biological availability of active peptides. Such a method is readily applicable to other legume-enriched food products.     

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.     

Prevention of lipid oxidation in muscle foods by milk proteins and peptides: A review

Muscle foods (especially fresh meat, precooked, and restructured meat products) are highly prone to lipid oxidation, which ultimately leads to certain problems, viz. discoloration, off-flavor, drip losses, loss of essential fatty acids and vitamins, and generation of toxic products. These problems can be minimized with the help of various agents and or techniques such as use of natural/synthetic antioxidants, metal chelating agents, physical conditions, vacuum packaging, and encapsulation techniques. Among these, the role of synthetic antioxidants is quite debatable due to certain health risks to humans. Among the natural molecules, milk proteins and their bioactive peptides offer a promising potential for the meat industry. Various forms of milk proteins and peptides including caseinates, whey proteins, skim milk, and milk co-precipitates can be used to prevent lipid oxidation in meat products either in the form of added ingredients or as edible coatings. However, in addition to prevention of lipid oxidation, they also provide nutritional benefits and improve the technological processing and shelflife of meat and meat products. This review focuses on the utilization, mechanism of action, and efficacy of milk proteins and peptides to inhibit lipid oxidation in muscle food products.     

Storage Stability of Food Protein Hydrolysates—A Review

In recent years, mainly due to the specific health benefits associated with (1) the discovery of bioactive peptides in protein hydrolysates, (2) the reduction of protein allergenicity by protein hydrolysis, and (3) the improved protein digestibility and absorption of protein hydrolysates, the utilization of protein hydrolysates in functional foods and beverages has significantly increased. Although the specific health benefits from different hydrolysates are somewhat proven, the delivery and/or stability of these benefits is debatable during distribution, storage, and consumption. In this review, we discuss (1) the quality changes in different food protein hydrolysates during storage; (2) the resulting changes in the structure and texture of three food matrices, i.e., low moisture foods (LMF, a_w < 0.6), intermediate moisture foods (IMF, 0.6 ≤ a_w < 0.85), and high moisture foods (HMF, a_w ≥ 0.85); and (3) the potential solutions to improve storage stability of food protein hydrolysates. In addition, we note there is a great need for evaluation of biofunction availability of bioactive peptides in food protein hydrolysates during storage.     

Enzymatic hydrolysis of soy proteins and the hydrolysates utilisation

Soy proteins are very important protein source for human being and livestock. Enzymatic hydrolysis of soy protein can enhance or reduce its functional properties and improve its nutritious value. Soy protein hydrolysates were primarily used as functional food ingredients, flavour and nutritious enhancers, protein substitute, and clinical products. Conditions for hydrolysis were usually mild, whereas recently high pressure treatment attracted more interest. Degree of hydrolysis (DH) was usually between 1% and 39.5%. The main problem associated with proteolytic hydrolysis of soy protein was production of bitter taste, hydrolysates coagulation and high cost of enzymes. Bitterness reduction can be achieved by control of DH, selective separation of bitter peptides from hydrolysates, treatment of hydrolysates with exo‐peptidases, addition of various components [adenosine monophosphate (AMP), some amino acids, monosodium glutamate (MSG), etc.] to block or mask the bitter taste, and modification of taste signalling. Hydrolysates coagulation can be resolved by selecting appropriate enzymes and by applying immobilisation technology the production cost can be reduced. Enzymatic hydrolysis also enhances bioactivity of soy proteins through conversion of glycosides to aglycones, increasing antioxidant and immunoregulatory properties. Finally, future works have been discussed.     

Bioactive peptides derived from bovine whey proteins: opioid and ace-inhibitory peptides

Regulatory peptides can be released by enzymatic proteolysis of food proteins and may act as potential physiological modulators of metabolism during the intestinal digestion of the diet. The possible regulatory effects of peptides relate to nutrient uptake, immune defence, opioid and antihypertensive activities. Milk proteins, especially caseins, are an important source of these bioactive peptides. During recent years, major whey protein components, α-lactalbumin and β-lactoglobulin, were also shown to contain bioactive sequences. Peptides showing opioid and angiotensin I-converting enzyme (ACE) inhibitory activity were found in α-lactalbumin and β-lactoglobulin. Opioid peptides, α-lactorphin and β-lactorphin, were liberated during in vitro proteolysis of bovine whey proteins, and pharmacological activity was observed at micromolar concentrations. Whey hydrolysates showed ACE-inhibitory activity after proteolysis with different digestive enzymes, and several active peptides were identified. The results demonstrated the existence of several biologically active whey-derived peptides and hydrolysates. The findings of the study can be exploited in the development of foods with special health claims (e.g. treatment of hypertension) as well as in identifying new applications in food.     

Innovative applications of high-intensity ultrasound in the development of functional food ingredients: Production of protein hydrolysates and bioactive peptides

In recent years, the research on functional peptide generation for the development of functional foods has focused, among other issues, on the enhancement of enzymatic hydrolysis by means of high-intensity ultrasound (HIU) application. It has been suggested that the use of HIU in pretreatment and during the hydrolysis process can modify protein conformation by affecting hydrogen bonds and hydrophobic interactions, disrupting the quaternary and/or tertiary structure of proteins due to the effects of cavitation. Therefore, these structural modifications may expose more hydrolysis sites to be accessible by the enzyme, causing an increase in degree of hydrolysis and bioactivity. The main objective of this work was to review recent advances in food science and technology on the application of HIU for the enhancement of enzymatic hydrolysis of proteins of both animal and plant origin in order to generate novel protein hydrolysates and bioactive peptides which could be used as functional-food ingredients.     

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.