牛乳蛋白过敏综述

通过目前对过敏的诱发和免疫机理的了解,探讨了牛乳过敏(CMA)的流行病学和自然进程,并对过敏反应的初级和次级预防的策略及正在进行的有效彻底治愈CMA的研究进行分析。     

牛乳蛋白过敏综述

牛乳过敏(CMA)是一种复杂的无序状态。许多牛乳蛋白均可引起过敏。牛乳蛋白过敏受多种免疫机制驱动。过敏发生率和占主导地位的过敏机制随年龄改变,一般婴儿中易发生IgE介导型过敏,成人过敏多为非IgE介导。CMA真实患者或疑似患者及早避食乳制品和及时给予喂养指导十分重要。本文通过目前对过敏的诱发和免疫机理的了解探讨CMA的流行病学和自然进程。并对过敏反应的初级和次级预防的策略及正在进行的有效彻底治愈CMA的研究进行分析。     

牛乳蛋白过敏原改性的研究

对牛乳中的主要过敏原酪蛋白、β-乳球蛋白（β-LG）及α-乳白蛋白（α-LA）进行了介绍。重点论述了热处理、蛋白水解、糖基化作用和乳酸发酵等技术对乳蛋白过敏改性的研究现状，提出了牛乳中过敏蛋白原改性的研究方向。     

婴幼儿牛乳蛋白过敏症的研究进展

牛乳蛋白过敏症属于食品安全范畴,同时也涉及到临床医学领域.随着社会的发展,牛乳蛋白过敏越来越引起人们的关注.综述了婴幼儿牛乳蛋白过敏症的发生机制和分型、临床症状、检测手段、牛乳中引发婴幼儿牛乳蛋白过敏症的过敏原的改性等几个方面的研究进展.     

降低牛乳蛋白致敏性的改性方法研究进展

近年来,牛乳过敏的发病率增加,引起了国内外的广泛关注,已经成为研究热点之一。牛乳中的蛋白质是引起过敏的主要原因,其中酪蛋白、β-乳球蛋白、以及α-乳白蛋白是主要过敏原。研究概述了牛乳蛋白过敏的免疫病理机制以及引起牛乳蛋白过敏的主要过敏原,主要介绍了目前国内外研究中采用的改性方法的技术进展,包括热处理、糖基化、高压处理、酶法水解等,同时列举了诸多实例,并对其进行分析总结。通过改性方法可以一定程度上降低致敏性,但是关于过敏机理、适用性以及改性过程中是否会出现新的过敏原表位的问题仍然需要进一步的研究。     

热处理对牦牛乳蛋白稳定性的影响

以牦牛乳为原料,研究其在不同热处理强度下所发生的理化性质及聚集行为,根据SDS-PAGE图谱分析乳蛋白的交联情况,分析乳蛋白的热稳定和热聚集特性。结果表明,热处理导致牦牛乳蛋白变性,发生一定程度的聚集,从而降低体系的稳定性。75℃时聚集物主要是由二硫键作用导致的,温度高于75℃时,巯基-二硫键相互作用逐渐增强,且表面疏水性稳定在较高水平。     

牛乳蛋白抗原性研究现状概述

乳蛋白是衡量乳制品营养价值的重要指标。文中介绍了牛乳蛋白的种类、结构、性质和抗原性强弱,比较了不同蛋白抗原的免疫抗体的特异性、交叉性、采用不同检测方法的检测限等。对酶联免疫吸附测定乳蛋白的优缺点进行了阐述,并展望了其应用前景。     

乳酸菌发酵降低牛乳蛋白致敏性的研究进展

牛乳及乳制品过敏是婴儿最常见的食物过敏,近年来牛乳过敏患病率迅速增加.乳制品过敏是指人摄入过敏原成分后,导致组织或器官损伤,从而引起的一系列临床症状的免疫反应.牛乳过敏严重影响患者及家人的生活质量,甚至较慢性儿童疾病影响更甚.虽然临床上使用不同配方的蛋白水解物替代牛乳,但是水解蛋白婴儿配方粉的苦味和婴儿生长缓慢等营养问...     

牛乳蛋白过敏综述

牛乳蛋白过敏主要发生在牛乳喂养的婴幼儿群体中,它的临床症状主要表现为：频繁胃食管反流、呕吐、非感染（或药物及其它原因）所致的荨麻疹、慢性腹泻、拒食或呕吐引起的生长发育障碍,严重影响了婴幼儿的成长发育。众多研究表明：β-乳球蛋白和α一乳白蛋白是婴幼儿牛乳蛋白过敏的主要过敏原。本文从牛乳蛋白过敏症的发生机理、临床症状、诊断治疗、预防、治疗机理等方面进行综述,以兹为低过敏或抗过敏婴幼儿配方食品开发提供思路,同时对具有过敏风险的婴幼儿提供喂养建议。     

胰蛋白酶水解对乳蛋白抗原性影响的研究

以胰蛋白酶为水解用酶,利用小鼠动物模型从体外和体内两个方面研究了水解作用对牛乳蛋白抗原性的影响。结果表明,胰蛋白酶水解的最适条件为50℃,E/S为0.6%下水解1.5 h。此水解条件下乳蛋白的总致敏性降低最多,分别为α-乳白蛋白(α-LA)抗原性降低率为80.16%,β-乳球蛋白(β-LG)抗原性降低率为51.94%,酪蛋白(CN)抗原性降低率为73.26%。动物实验表明:酶解组小鼠过敏症状较未水解的牛乳蛋白组相比明显减轻。与乳蛋白相比,酶解物显著抑制特异性IgE的产生,IgE质量浓度下降了42.36%。血浆组胺实验表明,酶解物降低血浆中组胺的释放,组胺质量浓度比乳蛋白组下降了32.77%。     

豆奶稳定性的探讨

主要研究了原材料,加工工艺,乳化剂及稳定剂对豆奶稳定性的影响。     

Effect of partial whey protein depletion during membrane filtration on thermal stability of milk concentrates

Membrane filtration technologies are widespread unit operations in the dairy industry, often employed to obtain ingredients with tailored processing functionalities. The objective of this work was to better understand the effect of partial removal of whey proteins by microfiltration (MF) on the heat stability of the fresh concentrates. The micellar casein concentrates were compared with control concentrates obtained using ultrafiltration (UF). Pasteurized milk was microfiltered (80 kDa polysulfone membrane) or ultrafiltered (30 kDa cellulose membrane) without diafiltration (i.e., no addition of water) to 2× and 4× concentration, based on volume reduction. The final concentrates showed no differences in pH, casein micelle size, or mineral concentration in the serum phase. The micellar casein retentates (obtained by MF) showed a 20 and 40% decrease in whey protein concentration compared with the corresponding UF milk protein concentrates for 2× and 4× concentration, respectively. The heat coagulation time decreased with increasing protein concentration, regardless of the treatment; however, MF retentates showed a higher thermal stability than the corresponding UF controls. The average diameter for casein micelles increased after heating in UF but not MF concentrates. The turbidity (measured by light scattering) increased after heating, but to a higher extent for UF retentates than for MF retentates at the same protein concentration. It was concluded that the reduced amount of whey protein in the MF retentates caused a significant increase in the heat stability compared with the corresponding UF retentates. This difference was not due to ionic composition differences or pH, but to the type and amount of complexes formed in the serum phase.     

Comparing the heat stability of soya protein and milk whey protein emulsions

The heat stability of emulsions stabilized by WPC or SPI or mixtures of the two are compared by following the change in oil droplet number during heating, and applying kinetic rate equations to calculate the rate constant (k) for destabilization. SPI emulsions were found to be unstable to heat at pH around the pI, whilst being stable at pH further from the pI. This is related to the pH dependent solubility of soy proteins. This determined that a pH close to the pI (pH 4.5) be used for further studies so as to give a heat labile emulsion. Both WPC and SPI emulsions showed a weak dependence of k on protein concentration at pH 4.5, and an increasing k as the temperature increased. Arrhenius plots for emulsions made with WPC were bilinear, whilst those for SPI followed a single straight line. The change in slope of the Arrhenius plots for the WPC emulsions occurred around 70 °C, lower than would be expected from the denaturation temperature of β-lactoglobulin, the protein that dominates the thermal behaviour of WPC. The activation energies for WPC and SPI emulsions calculated from the slopes of the Arrhenius plots are slightly lower for WPC and considerably lower for SPI than the equivalent values in the literature for these proteins in solution. This, and the apparent lower denaturation temperature of β-lactoglobulin in emulsions, we explain by hypothesizing that the WPC and SPI proteins are already partially denatured by surface adsorption when they are heated, and thus require less energy to denature, and unfold at lower temperatures than native non-adsorbed proteins.     

大豆蛋白奶工艺配方优化研究

对大豆蛋白奶的配方组成进行了研究，并对杀菌工艺进行了优化，最终确定了大豆蛋白奶的最佳配方和最佳杀菌工艺。     

Short communication: Effect of pH on the heat stability of reconstituted reduced calcium milk protein concentrate dispersions

This study aimed to investigate the heat stability of dispersions from reconstituted reduced-calcium milk protein concentrate (RCMPC) with 80% protein or more. The tested RCMPC powders were produced from skim milk subjected to CO₂ treatment before and during the process of ultrafiltration. The CO₂ injection was controlled to obtain 0 (control, no CO₂ injection), 20, 30, and 40% reduction in calcium levels in the RCMPC powders. The RCMPC powders were reconstituted to 10% (wt/wt) protein in deionized water. These dispersions were tested for heat stability in a rocking oil bath at 140°C at unadjusted, 6.5, 6.7, 6.9, and 7.1 pH. Calcium ion activity (CIA) and ionic strength measurements were carried out using a Ca ion-selective electrode and conductivity meter. Unadjusted pH of the dispersions varied from 6.8 in control to 5.96 in 40% RCMPC dispersions. The CIA of unadjusted dispersions ranged from 1.31 mM in control to 2.83 mM in 40% RCMPC. Heat stability, expressed as heat coagulation time (HCT) of unadjusted dispersions decreased as the level of Ca removal in powders increased (from 13.81 min in control to 0.46 min in 40% RCMPC) and was negatively correlated with the CIA of the dispersions. For control RCMPC dispersions, the minimum and maximum heat stability were observed at dispersion pH of 6.5 and 6.9, respectively, followed by a decrease at pH 7.1 (CIA was the lowest). Dispersions from 40% RCMPC and pH 7.1 had the maximum HCT of 30.94 min among all RCMPC dispersions at all pH values. From this study, it can be concluded that improved heat stability in high protein formulation beverages subjected to UHT processing could be achieved through calcium reduction in milk protein concentrates using CO₂ injection.     

无机盐对牛乳蛋白质胶体稳定体系影响的研究

通过测定牛乳蛋白质变性温度研究钙盐、磷酸盐、柠檬酸盐在不同离子浓度下对牛乳热稳定性的影响,结果表明:在鲜牛乳、脱脂奶粉复原乳中随钙离子浓度增大,变性温度降低,即热稳定性降低;增加磷酸盐浓度并未提高牛乳的热稳定性,反而使牛乳的热稳定性降低;添加适量的柠檬酸盐可提高牛乳的热稳定性,超过一定量则使热稳定性降低。     

黑豆山楂发酵乳稳定性的研究

通过对黑豆山楂发酵乳稳定性的研究，获得了重要的工艺参数和技术要点。实验结果表明，在均质温度60℃、均质压力25MPa下均质2次、杀菌温度85～95℃下，杀菌10～15min，在接种量为3％，温度42℃培养发酵3～4h、添加0．15％CMC、0．15％海藻酸钠和0．2％的单甘酯，所制得的产品均匀细腻，稳定性较好。     

豆浆中豆浆伴侣的鉴别方法研究

目的 鉴别豆浆中是否有豆浆伴侣存在。方法 制备含有不同浓度豆浆伴侣的豆浆, 加入硫酸镁, 计算沉淀凝固物的含量。结果 硫酸镁溶液不能使豆浆伴侣沉淀, 但能使大豆蛋白凝固, 进而能快速鉴别豆浆中是否含有豆浆伴侣。结论 此方法简便、可行。     

Changes in the physical properties,solubility, and heat stability of milk protein concentrates prepared from partially acidified milk

A limiting factor in using milk protein concentrates (MPC) as a high-quality protein source for different food applications is their poor reconstitutability. Solubilization of colloidal calcium phosphate (CCP) from casein micelles during membrane filtration (e.g., through acidification) may affect the structural organization of these protein particles and consequently the rehydration and functional properties of the resulting MPC powder. The main objective of this study was to investigate the effects of acidification of milk by glucono-δ-lactone (GDL) before ultrafiltration (UF) on the composition, physical properties, solubility, and thermal stability (after reconstitution) of MPC powders. The MPC samples were manufactured in duplicate, either by UF (65% protein, MPC65) or by UF followed by diafiltration (80% protein, MPC80), using pasteurized skim milk, at either the native milk pH (~pH 6.6) or at pH 6.0 after addition of GDL, followed by spray drying. Samples of different treatments were reconstituted at 5% (wt/wt) protein to compare their solubility and thermal stability. Powders were tested in duplicate for basic composition, calcium content, reconstitutability, particle size, particle density, and microstructure. Acidification of milk did not have any significant effect on the proximate composition, particle size, particle density, or surface morphology of the MPC powders; however, the total calcium content of MPC80 decreased significantly with acidification (from 1.84 ± 0.03 to 1.59 ± 0.03 g/100 g of powder). Calcium-depleted MPC80 powders were also more soluble than the control powders. Diafiltered dispersions were significantly less heat stable (at 120°C) than UF samples when dissolved at 5% solids. The present work contributes to a better understanding of the differences in MPC commonly observed during processing.     

调配型酸豆乳饮料稳定性的研究

主要研究魔芋胶、瓜尔豆胶与黄原胶对调配型酸豆乳稳定性的影响,通过对产品稳定性的分析测试及长时间观察,结果表明:当魔芋胶、瓜尔豆胶与黄原胶以3∶2∶3比例复配,用量为0.06%时,调配型酸豆乳的稳定性最好.