植物多酚与花生致敏蛋白相互作用及脱敏机理研究进展

花生过敏是最主要的食物过敏类型之一,花生致敏蛋白是主要致敏物质。当前解决花生过敏的方法如热加工法、基因工程方法和酶处理法等存在效率低,安全风险高、易破坏营养成分等缺点。植物多酚是一种天然植物活性物质,具有广泛的生理功能,如抗氧化、降糖、抗炎等,利用植物多酚与花生致敏蛋白相互作用是解决花生过敏的一项新途径,已有文献报道植物多酚具有抗过敏作用。本文主要阐述植物多酚与花生致敏蛋白的相互作用及植物多酚降低花生蛋白致敏性的潜在机理,并对该研究方向进行展望,以期为利用植物多酚解决花生过敏提供新思路。     

乳源过敏及低致敏乳制品的研究

对牛乳蛋白过敏原、牛乳蛋白的改性进行了阐述,并分析了加工过程对牛乳蛋白过敏原的影响,综述了当前国内外低致敏性乳制品的研究开发现状。     

胰蛋白酶水解降低乳蛋白过敏的研究

为获得低致敏的婴儿配方食品原料,对乳蛋白中的主要过敏原在水解过程中抗原抑制率的变化情况进行研究.采用间接竞争EUSA法检测水解过程中主要过敏蛋白——β-乳球蛋白(β-LG)、酪蛋白和牛血清白蛋白(BSA)的抗原抑制率的变化情况.结果表明:胰蛋白酶水解的最适条件为温度45℃,E/S 0.5%,水解时间1 h.在此水解条件下乳蛋白的总致敏性降低最多,其中β-乳球蛋白下降(55.93±3.63)%,酪蛋白下降(90.53±5.27)%和牛血清白蛋白下降(57.44±5.02)%.用胰蛋白酶水解乳蛋白可获得低致敏性的婴儿配方食品原料.     

多酚与蛋白质、消化酶相互作用的研究进展

近年来,随着人们对营养和功能性食品的需求逐渐增长,果奶、奶茶、可可奶和咖啡奶等含有乳蛋白和多酚的复合产品备受青睐,而复合体系中乳蛋白与多酚的相互作用及其对产品营养健康性的影响也成为目前的研究热点。消化道是影响食品营养健康特性发挥作用的重要场所,在消化环境食品多酚与乳蛋白、多酚与消化酶存在相互作用,它们之间的竞争性作用会影响乳蛋白的消化性和多酚的健康功能性,然而有关此方面的研究较少。因此,该文主要概述了国内外关于多酚和乳蛋白、多酚和消化酶间相互作用的研究进展,分析在消化环境中多酚功能性质的改变,以及研究乳蛋白与多酚复合体系蛋白消化性、抗氧化性和生物利用性的变化情况,以期为提高此类产品的营养和功能品质提供一定的指导依据。     

牛乳过敏原及加工技术对其致敏性的影响

对婴幼儿来说,牛乳营养丰富,是母乳最好的替代品,但牛乳中的蛋白质可能会引起过敏。牛乳中的主要过敏原是酪蛋白、β-乳球蛋白和α-乳白蛋白。本文从牛乳过敏原的结构和抗原表位、热处理、发酵和酶处理等不同的加工技术对牛乳蛋白致敏性的影响和过敏原标记检测方法三个方面进行了综述,为开发低致敏牛乳制品提供借鉴。      

益生菌改善牛乳蛋白过敏性的研究进展

牛奶蛋白过敏是儿童早期最常见的食物过敏反应之一,通常会持续到成年期。益生菌影响肠道微生物群并调节免疫反应。因此,它可能是可以缓解某些涉及肠道免疫系统疾病的工具,例如尚无治疗方法的牛乳蛋白过敏。本文中探讨了牛奶蛋白过敏的重要研究进展,介绍了牛乳蛋白过敏原和过敏机理。重点强调了益生菌在牛奶蛋白过敏方面取得的最新进展,通过调节肠道菌群和提高肠道免疫来改善牛乳蛋白过敏。最后阐述了低致敏性产品的研究现状,提出了研究及应用中面临的主要问题。益生菌改善牛乳蛋白过敏性的深入研究是过敏领域的重大突破,为缓解牛乳过敏提供理论依据。     

牛乳过敏原及加工技术对其致敏性的影响

对婴幼儿来说,牛乳营养丰富,是母乳最好的替代品,但牛乳中的蛋白质可能会引起过敏。牛乳中的主要过敏原是酪蛋白、β-乳球蛋白和α-乳白蛋白。本文从牛乳过敏原的结构和抗原表位、热处理、发酵和酶处理等不同的加工技术对牛乳蛋白致敏性的影响和过敏原标记检测方法三个方面进行了综述,为开发低致敏牛乳制品提供借鉴。     

谷物醇溶蛋白与植物多酚的互作机理及应用研究进展

谷物醇溶蛋白与植物多酚通常是食品基质中共存的两种重要成分,它们在食品的感官、功能特性和品质方面都起着关键作用。两者在食物体系中极易发生相互作用,从而影响两者的结构、功能属性以及生物利用度。本文首先讨论了谷物醇溶蛋白-植物多酚复合物的形成机制和影响因素,两者的相互作用包括非共价作用和共价作用,与其化学结构和制备复合物时所处的外部环境条件密切相关;然后讨论了两者相互作用对复合物功能属性的影响,包括对复合物乳化性、抗氧化活性和热稳定性的影响;最后综述了谷物醇溶蛋白-植物多酚复合物在乳液、薄膜和递送系统中的应用研究进展,以期为谷物醇溶蛋白和植物多酚的高值化利用、产品开发及在食品和相关领域的应用提供理论依据。     

降低牛乳中β-乳球蛋白致敏性方法的研究进展

摘要：牛乳过敏（CMA）是婴幼儿中一种常见的食物过敏,严重危害婴幼儿的身体健康。β-乳球蛋白（β-LG）是牛乳中重要营养物质,但却是引起牛乳蛋白过敏的主要过敏原。目前,降低牛乳中 β-LG 致敏性已经成为国内外研究热点之一。对CMA机制进行了介绍,综述了降低β-LG致敏性的常用方法,包括物理改性如热处理、高压处理、超声波处理,化学改性如糖基化、β-LG与脂肪酸结合、β-LG与多酚结合,酶法改性以及联合改性如物理改性联合酶水解改性、动态高压微射流技术联合脂肪酸处理、酶水解联合糖基化处理,旨在为生产低致敏性食品提供一定的理论依据。     

牛乳蛋白过敏及酶水解降低其致敏性的研究进展

牛乳蛋白营养丰富,在婴幼儿的生长发育中起关键作用,但部分人群会因为食用而发生过敏反应。为解决这一问题,目前工业上广泛使用酶水解牛乳蛋白,生产低致敏性婴儿配方乳粉。本文详述了牛乳中的主要致敏蛋白及其致敏的机制,主要牛乳致敏蛋白的抗体识别序列。介绍了酶水解在乳制品减敏中的应用,包括热加工辅助酶解法、非热加工辅助酶解法以及一些酶解前沿技术,并提出了一些对后续研究的思考。以期为生产低致敏性乳制品提供一些理论依据。     

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。     

Chemical,textural, rheological,and sensorial properties of wheyless feta cheese as influenced by replacement of milk protein concentrate with pea protein isolate

Replacement of milk protein with protein isolates from vegetable resources can significantly influence the characteristics of feta whey less cheese and also decrease the cost of final production. In this study, various blends of milk protein concentrate (MPC) and pea protein isolate (PPI) were mixed at levels of 12% MPC and 0% PPI (MP0), 10% MPC and 2% PPI (MP2), 9% MPC and 3% PPI (MP3), 8% MPC and 4% PPI (MP4), 7% MPC and 5% PPI (MP5), 6% MPC and 6% PPI (MP6) and used in the manufacture of wheyless feta cheese. The chemical, textural, rheological, and sensorial properties, as well as the microstructure of the cheese samples, were evaluated after 1, 15, and 30 days of storage. The general linear model procedure of SAS statistical software was used for statistical analysis. Duncan's multiple range tests was used to compare the means of different treatments. The results showed that all properties of the cheeses were influenced by different levels of PPI due to different total solids content. The use of high concentrations of PPI resulted in a more open protein network, softer structure and decreasing the storage (G′) and loss (G″) moduli in the cheeses. Sensory evaluation of the samples revealed that total score in terms of flavor, texture and overall acceptability was gradually decreased with increasing PPI levels, but still preferable for the panelists. Furthermore, for each sample, with increasing levels of PPI, the whiteness and the greenness were decreased, but the yellowness was increased.     

Effects of combined high-pressure homogenization and enzymatic treatment on extraction yield,hydrolysis and function properties of peanut proteins

Peanut protein isolate (PPI) was extracted by high-pressure homogenization (HPH) under 0.1 MPa (atmospheric pressure) and 40 or 80 MPa (high pressure). Effects of Alcalase (a proteolytic enzyme) on the enzymatic hydrolysis of PPI and the antioxidant activity of the PPI hydrolysates were investigated. The molecular weight distributions of the PPI hydrolysates were analyzed using Sephadex G-25 gel filtration chromatography while the antioxidant activities, including reducing power, 1,1-dipheny-2-picrylhydrazyl (DPPH) radical-scavenging activity and hydroxyl free radical-scavenging activity of the PPI hydrolysates were evaluated. The extraction yields of PPI by HPH under 0.1, 40 and 80 MPa were 16.84, 30.65 and 39.86%, respectively, which showed that HPH treatment improved the PPI extraction. The HPH treatment increased the degree of hydrolysis of PPI and significantly increased the reducing power and hydroxyl radical­scavenging activity. Furthermore, the molecular weight distributions of the PPI hydrolysates appeared principally over the range of 1000–5000 Da, while the HPH treatment enhanced the production of small peptides, which was in agreement with the high PPI hydrolysis degree. These results suggest that HPH treatment in combination with enzymatic hydrolysis could modify PPI properties and increase the antioxidant activities of the PPI hydrolysates.Industrial relevanceThis study was focused to evaluate the effects of high-pressure homogenization (HPH) in combination with enzymatic hydrolysis on extraction yield and enzymatic hydrolysis of PPI and antioxidant activity of the PPI hydrolysates. This study indicated the possibility of improving the availability of PPI by HPH treatment via increasing extraction yield and enzymatic hydrolysis of the PPI, which can provide a better utilization of the peanut by-product.     

The influence of milk with different compositions on the bioavailability of blackberry polyphenols in model sports nutrition beverages

This study aimed to determine whether the fat and protein content in dairy-fruit blends prepared using full-fat, semi-skimmed, skimmed or high-protein milk in combination with freeze-dried blackberry puree influenced the bioaccessibility and bioavailability of blackberry polyphenols and organic acids. Samples were subjected to in vitro digestion, after which bioavailability was analysed with a Caco-2 cell model. The addition of puree to milk resulted in the formation of protein aggregates, which partially protected anthocyanins during digestion. Milk fat may have increased the bioaccessibility of anthocyanins while reducing permeability through the Caco-2 cells, leading to a lower bioavailability in tested samples.     

Increased milk protein content and whey-to-casein ratio in milk served with breakfast cereal reduce postprandial glycemia in healthy adults: An examination of mechanisms of action

This study describes the effects on glycemic response and the underlying mechanisms of action of increasing the protein concentration and decreasing the casein-to-whey ratio in milk when consumed with a high glycemic breakfast cereal. Twelve healthy men and women, aged 18 to 30 yr and with a body mass index of 20 to 24.9 kg/m², consumed (in random order) milk beverages (250 mL) containing either 3.1 or 9.3% protein and casein-to-whey ratios of either 80:20 or 40:60. We measured postprandial appetite, glucose, regulatory hormones, and stomach emptying rate over 200 min, as well as food intake at an ad libitum meal at 120 min. Although pre-meal appetite was suppressed to a greater extent with milk beverages that had high (9.3%) compared with regular (3.1%) protein content, food intake was similar among all 4 treatments. Pre-meal mean blood glucose was lower with beverages that had high rather than regular milk protein content, with the lowest glucose peaks after the high milk protein treatment with the 40:60 casein-to-whey ratio. Pre-meal insulin and C-peptide levels were not affected by milk protein content or casein-to-whey ratio, but pre-meal glucagon-like peptide 1 was higher after the treatment containing high milk protein and the 40:60 casein-to-whey ratio, and pre-meal cholecystokinin was higher after the treatments containing high milk protein content. Plasma paracetamol response was also lower after the treatments containing high compared with regular milk protein content. When consumed with carbohydrate, milk beverages with high protein content and (to a lesser extent) a decreased casein-to-whey ratio lowered postprandial glycemia through insulin-independent mechanisms, primarily associated with delayed stomach emptying.     

Use of plant protein isolates in processed cheese

Plant protein isolates were evaluated and used to replace skim milk powdered protein in processed cheese blends. The chemical composition of chickpea protein isolate (CPI), peanut protein isolate (PPI) and sesame protein isolates (SPI) were determined. Functional properties of the tested protein isolates were also studied. SPI had minimum emulsion activity index (EAI), while the PPI possessed the highest value. The emulsions formed remained stable after one day, then destroyed at the 3rd day. Water absorption capacity (WAC) of the tested protein isolates varried between 196 to 329 g water/100 g protein. The water-oil absorption index (WOAI) for CPI, PPI and SPI were 7.6, 0.48 and 0.90, respectively. Changes in chemical composition of plant-type processed cheeses containing different levels of plant protein isolates (5, 10 and 15%), occurred only in total nitrogen, while the other constituents such as total solids, fat and salt were not affected. Sensory evaluation of the processed cheese revealed that total score gradually decreased with increasing plant-protein isolate levels up to 15% but still preferable for the consumer. This decrease in the total score regards the flavour but not to the colour or body and texture.     

The effect of milk protein on the bioavailability of cocoa polyphenols

ABSTRACT:  In order to determine whether milk proteins interact with cocoa polyphenols to modulate the uptake and concentration of polyphenols in plasma, 24 middle-aged men and women consumed 2 g of chocolate polyphenols, plus sugar and cocoa butter in 200 mL water, on 2 occasions. On 1 occasion, the chocolate mix contained 2.45 g of milk proteins. Blood samples were taken fasting and at regular intervals for 8 h. Catechin and epicatechins levels were measured in these samples and no differences were seen in average concentrations between the 2 treatments. Milk protein caused a slight increase in concentration at the early time points and a decrease at the later time points. In conclusion, milk powder did not influence the average concentration of polyphenols. While it slightly accelerated absorption, this is of no physiological significance.     

Non-covalent binding of proteins to polyphenols correlates with their amino acid sequence

The present paper describes the assessment of non-covalent binding (NCB) between milk proteins and polyphenols and its correlation with the physicochemical parameters of proteins. A method based on ultrafiltration and liquid chromatography-tandem mass spectrometry was used to analyse free and non-covalently bound polyphenols (ligands) in mixtures with major milk proteins. Binding strength values of individual polyphenols were normalised to those obtained with quercitrin (quercetin-3-O-rhamnoside), used as a reference compound. NCB data acquired by experiments at pH 6.6 without any preliminary protein denaturation were correlated with the physicochemical parameters of ligands and proteins. Unsupervised multivariate analysis revealed that NCB of proteins clustered according to their family (caseins separated from albumins). Based on this model, a predictive relationship was observed between protein-polyphenol binding strength and primary/secondary structure parameters of the proteins e.g. number of charges, proline residues and extended strand. These results confirm that, under the investigated experimental conditions, the NCB between polyphenols and protein mixtures can be predicted and optimised based on the molecular structures.     

负载茶多酚的花生分离蛋白-聚乳酸纳米纤维膜的制备及抗菌性能研究

利用静电纺丝技术制备负载茶多酚（TP）的花生分离蛋白（PPI）-聚乳酸（PLLA）复合纳米纤维薄膜，并研究其微观形貌、红外光谱结构、热稳定性、疏水性、晶体结构和抑菌性能等。傅里叶红外光谱和 X 射线衍射结果显示，复合纳米纤维成功包埋了TP，实验添加的TP对PPI/PLLA纳米纤维形态分布影响不大，其平均直径从（185±57）nm增加到（222±72）nm，而疏水性和热稳定性有所降低，但TP/PPI/PLLA复合纳米纤维膜提高了TP的热稳定性。抑菌结果表明:TP/PPI/PLLA三元复合纳米纤维膜对大肠杆菌和金黄色葡萄球菌的抑菌圈宽度分别从（0.75±0.03）cm和（1.49±0.08）cm增加到（1.10±0.02）cm和（1.82±0.10）cm，且对金黄色葡萄球菌的抑菌效果大于大肠杆菌的抑菌效果。由此研究表明，TP/PPI/PLLA三元复合纳米纤维膜具有良好的潜在应用价值。     

Effect of green tea catechins on physical stability and sensory quality of lactose-reduced UHT milk during storage for one year

Ultra-high temperature (UHT) processed lactose-reduced milk containing added green tea extract (GTE) at two concentrations (0.1% and 0.25%) was stored at 22 ± 2 °C for one year. The effect of GTE addition on physical stability, protein binding, and sensory quality was evaluated. Sedimentation in skim milk and creaming of full fat milk were inhibited by addition of GTE. The formation of Maillard-related flavour compounds was inhibited during storage as determined by dynamic headspace GC–MS. Using Western blot analysis, milk proteins were found to be highly conjugated to polyphenols. Addition of GTE before UHT treatment resulted in increased bitterness and astringency in UHT milk and this remained during storage. Even though GTE addition improved the physical stability and inhibited Maillard reactions in the milk, the taste and flavour contribution from GTE was dominating throughout storage, and alternative sources of polyphenols should be explored for increasing shelf-life stability of long-life milk.