Molecular property-affinity relationship of the interaction between dietary polyphenols and bovine milk proteins

The relationship between the molecular properties of dietary polyphenols and their affinities for bovine milk proteins (BMP) was investigated. The affinities of polyphenols for BMP were determined by means of fluorescence titration. The affinities of polyphenols for BMP increased with increasing partition coefficient and decreased with increasing hydrogen bond acceptor number of the polyphenol. From this point, the hydrophobic force played an important role in the binding interaction between polyphenols. It was found that the topological polar surface area value decreases with increasing binding constant of the polyphenol for BMP, which illustrates that the glycosylation of hydroxyl groups in polyphenols weakens their binding affinity for BMP. A strong correlation between Mulliken electronegativity and binding affinity was found (R = 0.64626), and Mulliken electronegativity values were found to increase with increasing binding constant of polyphenols for BMP. This illustrates that electrostatic interactions play a key role in binding dietary polyphenols to BMP.     

Thermal treatments affect the polyphenol profile and increase antioxidant capacity in five varieties of edible bean milks

We investigated the influence of two thermal treatments, steaming and boiling, on polyphenol profile and antioxidant capacity in milks from five edible bean varieties, including green mung bean milk, yellow and black soya bean milk, rice bean milk and white cow gram milk. The two thermal treatments had different influences on polyphenol profile and antioxidant capacity with steaming better than boiling in increasing total phenolic content (TPC) and antioxidant capacity in edible bean milks. In particular, steaming substantially increased soya bean isoflavone glucosides in the two soya bean milks. Bioconversion between polyphenols, the release of bound polyphenols and the induction of Maillard reaction products could contribute to the increase in TPC and antioxidant capacity in some edible bean milks. Therefore, it is recommended to steam edible bean milk for consumption, and edible bean milk containing antioxidant polyphenols can be developed into functional drinks with potential health benefits.     

茶多酚与牛奶蛋白互作对蛋白质离体消化率的影响

采用胃蛋白酶体外消化法和HPLC法测定了茶多酚与牛奶蛋白互作后蛋白质的离体消化率和几种主要儿茶素含量的变化,并用酒石酸铁比色法测定了两者互作后不同结合状态茶多酚的含量。结果表明:在牛奶蛋白含量为0.5%、茶多酚含量在0-10.0 g/kg的模拟奶茶溶液中,蛋白质的离体消化率随茶多酚浓度的增大而下降,茶多酚含量≥2.0 g/kg时牛奶蛋白的离体消化率显著降低;等体积的纯牛奶和茶水同时食用时,茶水中茶多酚含量≥2.5 g/L时牛奶蛋白的离体消化率显著降低。实验结果还表明,食用条件下茶多酚与牛奶蛋白的结合以物理结合为主,而其中EGCG和ECG 2种儿茶素与牛奶蛋白有较强的反应活性,对牛奶蛋白的离体消化率起主要影响作用。     

Almond Polyphenols: Methods of Analysis,Contribution to Food Quality,and Health Promotion

Almond is a nutrient‐dense tree nut recognized for its favorable lipid profile, vitamin E content, and polyphenols. The objectives of this review were to determine the polyphenols reported in almond, summarize the methods of analysis, and determine the polyphenol contribution to almond quality and health‐promoting activity. Approximately 130 different polyphenols have been identified in almond, although not all of these have been quantitated. The mean and 25% to 75% percentile contents reported in literature were 162 mg (67.1 to 257) proanthocyanidins (dimers or larger), 82.1 mg (72.9 to 91.5) hydrolysable tannins, 61.2 mg (13.0 to 93.8) flavonoids (non‐isoflavone), 5.5 mg (5.2 to 12) phenolic acids and aldehydes, and 0.7 mg (0.5 to 0.9) isoflavones, stilbenes, and lignans per 100 g almond. Following solvent extraction of almond, hydrolysis of the residue liberates additional proanthocyanidins, phenolic acids and aldehydes, and total phenols. Blanching and skin removal consistently reduces almond polyphenol content, but blanch water and almond skins retain enough polyphenols to be used as antimicrobial and antioxidant ingredients. Roasting and pasteurization have inconsistent effects on almond polyphenols. Almond polyphenols contribute to shelf life by inhibiting lipid oxidation and providing pigmentation, flavor, astringency, and antimicrobial activity. The health‐promoting activity of whole almonds has been widely investigated, but few have considered the contribution of polyphenols. Preclinical studies of polyphenol‐rich almond skin or almond extracts suggest putative effects on antioxidant function, detoxification, antiviral activity, anti‐inflammatory function, and topical use for inhibiting ultraviolet A damage. Therefore, almond has a diverse polyphenol profile contributing to both its food quality and health‐promoting actions.     

Interaction of dietary polyphenols with bovine milk proteins: molecular structure-affinity relationship and influencing bioactivity aspects

Scope : Dietary flavonoids and stilbenes are important polyphenols in foods, such as, e.g. fruits, vegetables, nuts, and tea as they are of great interest for their bioactivities, which are related to the anti‐oxidative property. Methods and results : The relationship between the structural properties of dietary polyphenols and their affinities for milk proteins (MP) was investigated. Methylation and methoxylation of flavonoids decreased (or hardly affected) the affinities for MP. Hydroxylation on the rings A and B of flavones and flavonols enhanced the interaction slightly. The hydroxylation on the ring A of flavanones significantly improved the affinities. Glycosylation of flavonoids weakened the affinities by 1–2 orders of magnitude. The hydrogenation of the C2?C3 double bond of flavonoids decreased the binding affinities by 7.24–75.86‐fold. Galloylation of catechins significantly improved the binding affinities by about 100–1000‐fold. Glycosylation of resveratrol decreased its affinity for MP. Esterification of gallic acid increased its binding affinity. MP significantly weakened the DPPH radical scavenging activity of polyphenols. The decreasing DPPH scavenging percentages of polyphenols increased with increasing affinities of MP–polyphenol complexes. Conclusion : The binding affinities with MP were strongly influenced by the structural differences of dietary polyphenols. The MP–polyphenol interaction weakened with the DPPH free radical scavenging potential of polyphenols.     

多酚-蛋白质共价作用及其对食品体系的影响研究进展

近年来多酚与蛋白质间的相互作用及其对食品体系的影响受到人们的极大关注。按作用方式可将多酚与蛋白质之间的相互作用分为非共价作用和共价作用。有关非共价作用的研究较完善,相比之下共价作用的研究报道非常少。为推动对食品体系中多酚与蛋白质共价作用的研究,在广泛查阅文献的基础上,本文综述了多酚与蛋白质共价结合的机理、影响因素以及这种结合对食品体系感官特性、功能与营养特性、安全性的影响,并进一步提出了有关食品体系中多酚与蛋白质共价作用今后的研究方向。     

Nuts, especially walnuts, have both antioxidant quantity and efficacy and exhibit significant potential health benefits

Free and total (after basic hydrolysis) polyphenols in nine types of raw and roasted nuts and two types of peanut butter (54 commercial samples) were analyzed after methanol extraction by a single step Folin-Ciocalteu reagent using catechin as standard. Walnuts had the highest free and total polyphenols in both the combined raw and roasted samples. Total polyphenols in the nuts were significantly higher than free polyphenols. Roasting had little effect on either free or total polyphenols in nuts. Raw and roasted walnuts had the highest total polyphenols. The efficacy of raw and roasted nut antioxidants was assessed by measuring the ability of the free polyphenol nut extracts to inhibit the oxidation of lower density lipoproteins (LDL + VLDL). A nut polyphenol, catechin, was measured after binding of three nut extracts to lower density lipoproteins. Walnut polyphenols had the best efficacy among the nuts and also the highest lipoprotein-bound antioxidant activity. Based on USDA availability data, the per capita total polyphenols was 162 mg from nuts per day in 2008. This corresponds to 19% of the total polyphenols from fruits and vegetables, nuts, grains, oils and spices in the US diet. Nuts provided 158 mg of polyphenols per day to the European Union diet. Nuts are high in polyphenol antioxidants which by binding to lipoproteins would inhibit oxidative processes that lead to atherosclerosis in vivo. In human supplementation studies nuts have been shown to improve the lipid profile, increase endothelial function and reduce inflammation, all without causing weight gain. These qualities make nuts a nutritious healthy snack and food additive.     

Bioactive peptides: Production and functionality

Milk proteins exert a wide range of nutritional, functional and biological activities. Many milk proteins possess specific biological properties that make these components potential ingredients of health-promoting foods. Increasing attention is being 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 (1) gastrointestinal digestion of milk, (2) fermentation of milk with proteolytic starter cultures or (3) hydrolysis by proteolytic enzymes. Milk protein derived peptides have been shown in vivo to exert various activities affecting, e.g., the digestive, cardiovascular, immune and nervous systems. Studies have identified a great number of peptide sequences with specific bioactivities in the major milk proteins and also the conditions for their release have been determined. Industrial-scale technologies suitable for the commercial production of bioactive milk peptides have been developed and launched recently. These technologies are based on novel membrane separation and ion exchange chromatographic methods being employed by the emerging dairy ingredient industry. A variety of naturally formed bioactive peptides have been found in fermented dairy products, such as yoghurt, sour milk and cheese. The health benefits attributed to peptides in these traditional products have, so far, not been established, however. On the other hand, there are already a few commercial dairy products supplemented with milk protein-derived bioactive peptides whose health benefits have been documented in clinical human studies. It is envisaged that this trend will expand as more knowledge is gained about the multifunctional properties and physiological functions of milk peptides.     

钙与乳蛋白的相互作用机制及对其功能特性的影响研究进展

钙作为人体骨骼生长和调节生理功能的重要物质,广泛存在于乳品中。钙与乳中蛋白质如αs-酪蛋白、β-酪蛋白、κ-酪蛋白、α-乳白蛋白和β-乳球蛋白等发生相互作用,影响乳蛋白的结构稳定性,进而使其热稳定性、乳化性、溶解性、起泡性和凝胶性发生改变。本文综述了钙与各种乳蛋白之间的相互作用机制以及对其功能特性的影响,对系统理解钙与乳蛋白的结合具有重要意义,为钙类功能性乳品的深入研究以及工业化生产提供理论依据。     

Coffee Antioxidant Properties: Effects of Milk Addition and Processing Conditions

ABSTRACT: In the human diet, coffee is the major source of caffeoyl-quinic acids known as powerful antioxidants. The aim of this study was to assess the effect of usual coffee consumption, such as the addition of milk, and of processing conditions, such as spray-drying, on beverage antioxidant power and potential polyphenol bioavailability impairments. When 25% milk was added to coffee, up to 40% of coffee chlorogenic acid were found to be bound to dairy proteins, using an ultrafiltration technique. However, neither milk addition nor spray-drying had a significant effect on beverage antioxidant power, evaluated using 2,2-diphenyl-1-pycrylhydrazyl (DPPH), 2-2'-azobis (2-amidinopropane) dihydrochloride (AAPH), and total antioxidant capacity (TAC) tests. Moreover, these interactions tended to decrease during in vitro gastric and intestinal digestion, thus suggesting that interactions between chlorogenic acid and milk proteins in coffee and milk beverage may not have any significant effect on coffee antioxidant power before and after consumption.     

Cocoa polyphenols accelerate vitamin B12 degradation in heated chocolate milk

The rate of vitamin B₁₂ loss was 3X greater in heated, chocolate‐flavoured milk than in unflavoured milk. Studies of B₁₂ stability in the presence of cocoa powder components were performed to identify the reactive agents. Cocoa polyphenols with a strong capacity both for reduction and for peroxide generation accelerated B₁₂ destruction as much as 20‐fold vs. polyphenols without both capacities. Polyphenols with both capacities include the cocoa polyphenol (+)‐catechin and oligomers thereof, but also the structurally related polyphenols gallic acid, caffeic acid and (?)‐epigallocatechin gallate. The demonstrated physical affinity of cocoa powder for B₁₂ was a significant factor in the destructive process. B₁₂ may exhibit decreased stability in heated, neutral pH, polyphenol‐fortified foods.     

Analytical techniques for the study of polyphenol–protein interactions

This mini review focuses on advances in biophysical techniques to study polyphenol interactions with proteins. Polyphenols have many beneficial pharmacological properties, as a result of which they have been the subject of intensive studies. The most conventional techniques described here can be divided into three groups: (i) methods used for screening (in-situ methods); (ii) methods used to gain insight into the mechanisms of polyphenol–protein interactions; and (iii) methods used to study protein aggregation and precipitation. All of these methods used to study polyphenol–protein interactions are based on modifications to the physicochemical properties of the polyphenols or proteins after binding/complex formation in solution. To date, numerous review articles have been published in the field of polyphenols. This review will give a brief insight in computational methods and biosensors and cell-based methods, spectroscopic methods including fluorescence emission, UV-vis adsorption, circular dichroism, Fourier transform infrared and mass spectrometry, nuclear magnetic resonance, X-ray diffraction, and light scattering techniques including small-angle X-ray scattering and small-angle neutron scattering, and calorimetric techniques (isothermal titration calorimetry and differential scanning calorimetry), microscopy, the techniques which have been successfully used for polyphenol–protein interactions. At the end the new methods based on single molecule detection with high potential to study polyphenol–protein interactions will be presented. The advantages and disadvantages of each technique will be discussed as well as the thermodynamic, kinetic or structural parameters, which can be obtained. The other relevant biophysical experimental techniques that have proven to be valuable, such electrochemical methods, hydrodynamic techniques and chromatographic techniques will not be described here.     

乳及乳制品蛋白质掺假检测研究进展

阐述两类方法、一个原则：乳及乳制品蛋白质掺假特异性检测方法和乳及乳制品蛋白质掺假非特异性检测方法;任何一种乳品蛋白质掺假检测方法的建立都要以某一特定蛋白质差异性为依据的原则。     

A 100-Year Review: Progress on the chemistry of milk and its components

Understanding the chemistry of milk and its components is critical to the production of consistent, high-quality dairy products as well as the development of new dairy ingredients. Over the past 100 yr we have gone from believing that milk has only 3 protein fractions to identifying all the major and minor types of milk proteins as well as discovering that they have genetic variants. The structure and physical properties of most of the milk proteins have been extensively studied. The structure of the casein micelle has been the subject of many studies, and the initial views on submicelles have given way to the current model of the micelle as being assembled as a result of the concerted action of several types of interactions (including hydrophobic and the formation of calcium phosphate nanoclusters). The benefits of this improved knowledge of the type and nature of casein interactions include better control of the cheesemaking process, more functional milk powders, development of new products such as cream liqueurs, and expanded food applications. Increasing knowledge of proteins and minerals was paralleled by developments in the analysis of milk fat and its synthesis together with greater knowledge of its packaging in the milk fat globule membrane. Advances in analytical techniques have been essential to the isolation and characterization of milk components. Milk testing has progressed from gross compositional analyses of the fat and total solids content to the rapid analysis of milk for a wide range of components for various purposes, such as diagnostic issues related to animal health. Up to the 1950s, research on dairy chemistry was mostly focused on topics such as protein fractionation, heat stability, acid–base buffering, freezing point, and the nature of the calcium phosphate present in milk. Between the 1950s and 1970s, there was a major focus on identifying all the main protein types, their sequences, variants, association behavior, and other physical properties. During the 1970s and 1980s, one of the major emphases in dairy research was on protein functionality and fractionation processes. The negative cloud over dairy fat has lifted recently due to multiple reviews and meta-analyses showing no association with chronic issues such as cardiovascular disease, but changing consumer misconceptions will take time. More recently, there has been a great deal of interest in the biological and nutritional components in milk and how these materials were uniquely designed by the cow to achieve this type of purpose.     

多酚对肠道微生物影响的研究进展及对多酚指示菌的探讨

肠道微生物近年来越来越受到人们重视,它们不仅数量庞大而且与宿主的健康息息相关。肠道微生物生态平衡的紊乱会导致肥胖、炎症、胰岛素抵抗甚至是精神性疾病。多酚类物质是重要的植物源功能性成分,许多研究表明多酚可以调节肠道微生物的生态平衡,改善其结构组成。现基于国内外多酚对肠道微生物影响的研究,总结了对多酚敏感的肠道菌,发现双歧杆菌(Bifidobacterium)、乳杆菌属(Lactobacillus)、Akkermansia muciniphila(简称A.muciniphila)等有成为多酚指示菌的潜质。希望本文能够为未来多酚对肠道微生物生态平衡影响的研究提供新思路。     

A review on polyphenols: Classification,beneficial effects and their application in dairy products

Recently, the number of studies regarding the physiological activities of food‐derived bioactives and food components with functional properties has greatly increased. Many studies have emphasised the beneficial effects of polyphenols regarding their antioxidant, antiproliferative and anti‐inflammatory properties. This study highlights their application in dairy products, notes in which form they are applied and discusses the effects on the physicochemical and sensory characteristics of products, although some dairy matrices remain unexploited. It was noted that the inclusion of polyphenols improves not only the antioxidant properties but also, in some cases, the sensory attributes. This review also includes the synthesis, classification and beneficial effects of polyphenols.     

蛋白质组学技术及其在乳及乳制品中的应用研究进展

蛋白质组学技术是近年来生命科学研究的重要工具,在食品、医学及动植物研究领域具有独特优势.利用蛋白质组学技术研究乳及乳制品,深入阐明其中蛋白质的表达及动态变化已成为当前的研究热点.该文主要综述了蛋白质组学的概念、常用技术及应用领域,重点介绍蛋白质组学在乳及乳制品领域,特别是在乳脂肪球膜蛋白、乳清蛋白、乳及乳制品加工过程以...     

纳米乳液改善多酚性能及在食品中的应用进展

国内外研究人员一直关注植物多酚促进人体健康的潜在作用,发现在实际应用中,多酚的稳定性差、溶解性差、生物利用率低等问题亟待解决。纳米乳液递送体系粒径小、稳定性佳,是极佳的多酚递送体系,应用前景广阔。经纳米乳液包埋后的多酚可改善稳定性,提高在体内的生物利用率,表现出更佳的生物可及性、抗氧化性及抗肿瘤活性,更适合应用于食品工业。该研究结合国内外研究者的成果综述了多酚的分类及作用;多酚纳米乳液制备新技术;纳米乳包载对多酚多种性能的改善效果与作用机制。基于多酚纳米乳液需解决的首要问题提出了乳液优化方案,并阐述了多酚纳米乳液在食品工业中的现状及潜在应用,对多酚纳米乳液未来的制备方向进行展望。     

Fortification using grape extract polyphenols – a review on functional food regulations

Grapes are rich sources of polyphenols and widely used in food fortification due to their health-promoting properties. Previous studies have provided systematic strategies on foods fortified with grape polyphenols; however, until now, very little is known about grape polyphenol market, fortification and their health food regulations. It is, therefore, necessary to make a comprehensive overview of grape extract polyphenols and their fortification in functional foods. Hence, we reviewed the grape polyphenol market, fortification, health food market scenario and functional food regulations. The global grape polyphenol market is expected to rise 946.90 million USD by 2023 with its own trademark as polyphenol-fortified functional foods. This is ultimately due to acceptability, extensive use, marketing of polyphenol-fortified functional foods and their favourable food regulations. The future perspective on grape polyphenols research should be focused on extraction of polyphenols from grape waste and their fortification in functional foods.     

Effect of Temperature and Fermentation Time on Phytic Acid and Polyphenol Content of Rabadi— A Fermented Pearl Millet Food

Rnbadi was prepared by fermenting a mixture of pearl millet flour and butter milk for three periods of time (3, 6 and 9 hr) at four temperatures (35°, 40°, 45° and 50°C). Temperature had little influence on degradation of either phytic acid or polyphenol content. At all temperatures the phytic acid and polyphenol content decreased with an increase in fermentation time. Nine hour fermentation resulted in maximum reduction of phytic acid (27–30%) as well as total polyphenols (1–12%) at all temperatures. Phytic acid was reduced to a greater extent than polyphenols.