大豆蛋白亚基与豆腐的质构特性的相关性

采用SDS-PAGE电泳技术,对河南省16个不同大豆品种中水溶性蛋白组分的构成和含量进行了系统的分析,对大豆蛋白亚基与豆腐的质构特性进行相关性分析。结果显示:品种间7S组分及其亚基的含量差异显著,其中α'亚基与质构特性的硬度、弹性、黏聚性和回复性指标均呈极显著负相关;α亚基与硬度指标呈极显著负相关;β亚基与硬度、弹性、黏聚性和回复性指标均呈极显著负相关。而11S组分及其亚基含量差异较小,其中BS组分与黏聚性指标呈极显著正相关。11S/7S与硬度、弹性、黏聚性指标呈极显著正相关,与回复性指标呈显著正相关。     

不同亚基变异类型的大豆分离蛋白凝胶质构特性的研究

以6个蛋白亚基含量变异类型大豆品种制备的分离蛋白为材料,采用SDS-PAGE测定了蛋白亚基的含量以及采用质构仪测定了凝胶的质构特性,并对结果进行了相关性分析.结果表明：不同品种制备的分离蛋白在凝胶的硬度、粘性、内聚性、胶粘性、咀嚼性、回弹性、破裂强度等特性方面存在显著差异,而在凝胶弹性上无显著差异;桂阳紫金豆制备的分离蛋白凝胶具有最高的硬度、弹性、内聚性、胶粘性、咀嚼性、回弹性和破裂强度值,而西峡小粒黄制备的分离蛋白凝胶具有最低的硬度、粘性、胶粘性、咀嚼性、回弹性和破裂强度值;大豆分离蛋白各亚基含量与凝胶各质构特性在相关程度和相关性质上也存在差异,尤以A3和B4亚基对分离蛋白质构特性影响较大;7S、11S组分含量和11S/7S比值与分离蛋白凝胶质构特性无显著相关关系.     

大豆蛋白组分与豆腐品质特性的研究

选用16种大豆品种作为本实验的研究原料,测定了各个品种大豆中的蛋白质、水溶性蛋白及各组分亚基的含量,再将这16种大豆原料分别做成豆腐,测定豆腐的得率、保水性及质构特性,通过方差分析得知豆腐湿基和干基得率差异性都比较大,保水性差异不大,各项质构参数差异较大。将大豆蛋白各组分含量与豆腐品质特性进行相关性分析得知大豆中蛋白质、水溶性蛋白及各组分亚基含量与豆腐的得率、保水性及质构特性均呈显著或极显著相关关系。豆腐的品质特性与大豆中7S组分及其亚基含量之间有着显著或极显著负相关关系;与11S组分及其亚基含量之间有着显著或极显著正相关关系,与11S/7S之间有着极显著正相关关系。将豆腐品质特性做聚类分析,由结果可得出:蒙9413、中黄13、中豆20、合丰55和合丰56这5种大豆品种作为原料所制的豆腐的得率、保水性以及质构特性较其他品种好。     

大豆组分与北豆腐得率及品质的相关性研究

选取11种大豆为原料,研究了大豆组分与制成的北豆腐得率、品质指标(保水性、质构指标)之间的关系。结果表明:北豆腐湿基、干基得率及保水性均与大豆中蛋白质含量、水溶性蛋白质含量、11S亚基含量以及11S/7S呈显著正相关,与大豆中脂肪含量呈显著负相关。北豆腐硬度与大豆蛋白质、水溶性蛋白质、11S亚基含量以及11S/7S均呈显著负相关;北豆腐弹性与7S、11S亚基含量呈显著负相关;北豆腐黏聚性与大豆水溶性蛋白质、植酸含量呈显著负相关,与7S、11S亚基含量呈极显著正相关;胶着性与大豆水溶性蛋白质呈极显著负相关。聚类分析结果显示,用郑9525、郑94059和郑0102这3种大豆制作的北豆腐得率、保水性及质构特性均较好。     

改性醇法大豆浓缩蛋白结构与功能性的相关性分析

大豆蛋白的结构与功能性之间具有一定的相关性,通过结构可以预测大豆蛋白的功能性,而知道功能性亦可了解它的某些组成和结构特征。主要对氨处理醇法大豆浓缩蛋白(ALSPC)的结构和功能性之间进行了相关性分析。分析结果显示:表面疏水性与溶解性、乳化性呈极显著的线性正相关,而与凝胶性相关性不显著;游离巯基、二硫键与溶解性呈极显著的线性负相关,与凝胶性的相关性不显著;游离巯基与乳化性呈极显著的线性负相关,二硫键与乳化性呈显著的线性负相关。     

芸豆蛋白的理化功能特性研究

选取4个芸豆品种,以大豆蛋白为对照,采用碱提酸沉法提取芸豆蛋白并分析其理化功能特性。结果表明:芸豆蛋白含有9种必需氨基酸,且必需氨基酸占总氨基酸的比例(57%~62%)高于大豆蛋白(47%),黑芸豆的限制性氨基酸比例(2.59%)高于其他参试品种及大豆蛋白(1.53%~1.89%)。不同品种芸豆蛋白亚基主要分布在47 ku左右,由2个或3个亚基组成,次要条带间存在一定差异,大豆蛋白的条带与芸豆蛋白条带显著不同。芸豆蛋白的溶解性和吸水性略低于大豆蛋白,乳化性及乳化稳定性、发泡性及泡沫稳定性、吸油性和最小凝胶浓度均接近或高于大豆蛋白,红芸豆和白芸豆蛋白的功能特性高于黄芸豆和黑芸豆蛋白。     

猪血浆蛋白与大豆蛋白在乳化肠中的应用

添加外源蛋白对肉肠类食品进行改性是目前的一个研究热点.以猪血浆蛋白和大豆蛋白为外源蛋白,按比例添加于乳化肠中,考察不同外源蛋白对乳化肠表面结构、色差、质构、剪切力的影响.结果表明:添加2%～6%的猪血浆蛋白可以显著降低乳化肠的蒸煮损失(P<0.05),提高猪肉凝胶的硬度、弹性、咀嚼度、回复性和剪切力,改善肉糜凝胶的质构,同时引起肠色泽的显著变化;而大豆蛋白在较低浓度时也表现出较好的降低乳化肠蒸煮损失率的特性,但对肠凝胶质构特性和色泽影响不显著.     

亚基水平上大豆蛋白凝胶性的研究进展

大豆蛋白主要由β-伴大豆球蛋白（7S球蛋白）和大豆球蛋白（11S球蛋白）组成,不同亚基组成直接影响着大豆蛋白的加工特性。凝胶特性是本研究的主题。本文总结了大豆蛋白的组成及其化学结构,介绍7S球蛋白和11S球蛋白的凝胶形成过程,同时对亚基组分对凝胶性的影响和蛋白亚基缺失型大豆的研究进展进行概述,为大豆蛋白产品的开发及应用提供重要的理论指导。     

大豆蛋白与豆腐品质关系的研究

通过分析大豆蛋白的含量及组分与豆腐的硬度、弹性等质构性质、保水性、得率等方面的相关性,研究了大豆蛋白与豆腐品质的关系。研究表明:大豆水溶性蛋白组分中含有的7S及其亚基对豆腐的质构特性和得率产生了不利影响,11S及其亚基有助于豆腐的质构特性和得率的提升,11S/7S比值越高,豆腐质构特性和得率越好。     

大豆分离蛋白添加方式对猪肉凝胶特性的影响

大豆分离蛋白是肉制品加工中常用的植物蛋白,能够改善肉制品品质,但添加方式影响肉制品质量。本文研究添加大豆分离蛋白和11S球蛋白变性的大豆分离蛋白乳化猪背膘对猪肉肉糜蒸煮得率、乳化稳定性及猪肉凝胶色差和质构的影响,并应用低场核磁共振技术,研究不同处理猪肉凝胶中水分分布状态和水分迁移特性的异同。与添加大豆分离蛋白相比,添加大豆分离蛋白乳化猪背膘显著提高(P0.05)猪肉肉糜的蒸煮得率和乳化稳定性,提高凝胶的L*-值和b*-值,硬度、弹性、内聚性和咀嚼性等。低场核磁共振结果表明:添加大豆分离蛋白乳化猪背膘的凝胶,T_(2b)和T_(22)弛豫时间较短,说明水分可移动性降低;T_(21)的峰比例增加,而T_(22)的峰比例降低,说明不易流动的水分含量增加,凝胶有较好的保水性。     

Labile protein reserves and protein turnover.

The concept of a labile protein reserve is based on the relatively slow establishment of a new equilibrium in the rate of nitrogen excretion after an abrupt change in dietary supply. The evidence reviewed shows that a majority of this nitrogen is derived from or deposited in skeletal muscle proteins. The rates of synthesis and degradation of total body protein are rapid in large animals (man and swine) and are correlated with heat production. The rate of protein synthesis in skeletal muscle greatly exceeds the rate of growth and is sensitive to nutritional status. The rate exceeds the rate of degradation in response to the ingestion of an adequate diet so that tissue proteins are accumulated, but it decreases below the rate of degradation under conditions of deprivation. In this latter state, proteins of skeletal muscle supply amino acids for energy or for the synthesis of other more essential proteins, e.g., milk proteins during lactation. Thus, we conclude that the labile protein reserve is a product of the normal, dynamic metabolism of protein.     

Fermentation modifies protein/protein and protein/starch interactions in sorghum dough

A study was made on the molecular and structural changes occurring in the protein and starch components of sorghum flour when fermented to prepare typical non-malted Sudanese foods. Protein solubility and SDS-PAGE studies indicated that water-soluble proteins are the main target of hydrolysis during fermentation. Proteolysis products are taken up for bacterial growth. Kafirins are among the proteins left intact by proteolytic events in the fermentation step. Upon cooking in boiling water kafirins are converted into protein aggregates almost insoluble even in the presence of 8 M urea and of disulphide-reducing agents. Viscoamylographic and microstructural studies indicate that fermentation leads to the release of starch granules from very compact structures in the original sorghum flour, in which proteolysis-sensitive, water-soluble proteins form an essential part of the outermost shell of large structures, where starch granules are embedded into a kafirin-rich protein matrix that is not affected by proteolytic events during fermentation.     

肌原纤维蛋白双蛋白乳饮料的研制

介绍了肌原纤维蛋白双蛋白乳饮料生产所需的材料、设备、工艺流程、操作要点、质量指标,确定了产品所需肌原纤维蛋白的种类、甜味剂的种类、乳化稳定剂的添加量,通过正交试验和极差分析得出肌原纤维蛋白双蛋白乳饮料的较优配方为:全脂乳粉3.5%、肌原纤维蛋白0.3%、复合甜味剂(以蔗糖计)9%、酸含量(以柠檬酸计)0.4%、复合乳化稳定剂0.40%、柠檬酸钠0.1%、食用香精0.03%。     

Nutritive value of a new protein product--dry protein mixture

A dry protein mixture (DPM) consists of dry slaughtered animal blood clarified by means of the peroxide-catalase system and dry skim milk at a ratio of 1:1. A study was made of organoleptic properties of the DPM, the composition of nutrients and biological efficacy in experiments on animals. The DPM is light yellow powder without specific taste and odor of blood, contains 58.4% of protein, 1.36% of fat, 26.71% of carbohydrates (lactose), and 8.19% of mineral substances. DPM proteins contain all the essential amino acids. As regards their biological efficacy they are not inferior to that of casein. The DPM is rich in calcium (606 mg/100 ml), phosphorus (645 mg/100 ml) and particularly in iron (106 mg/100 ml). Digestibility of iron examined on rats appeared to be high (31.2%). The new product is recommended for rational and dietetic nutrition.     

Perspectives of lupine wholemeal protein and protein isolates biodegradation

Lupine (Lupinus angustifolius L.) protein (in wholemeal and protein isolates) was biodegraded using Pediococcus acidilactici in submerged and solid-state fermentation conditions. The changes in the molecular weight of lupine protein fractions, amino acid (AA) profile, biogenic amine formation, antimicrobial and antioxidant properties, and protein digestibility in vitro and in vivo (in Wistar rats) were evaluated. After biotreatment, lower molecular weight peptides (from 10 to 20 kDa) were established, and the free AA content increased. Biodegradation improved the antioxidant properties, modulated the antimicrobial properties, and led to higher in vitro and in vivo digestibility and functionality of the lupine in treated rats (significant increase in body weight of Wistar rats, and increased acetic acid concentration and lowered Escherichia coli count in the caecum). Overall, the biodegradation of lupine protein can transform the plant protein, producing enhanced functionality and bioavailable products.     

Oil globule microstructure of protein/polysaccharide or protein/protein bilayer emulsions at various pH

The microstructure of oil droplets of bi-layer emulsions was studied as a function of pH (i.e. 7, 5, and 3) using scanning electron microscopy. The bi-layer emulsions consisted of a primary emulsion: 5 wt% soybean oil (SBO) in a 1% protein (nonfat dry milk) aqueous solution. The secondary layer was ι-carrageenan, high- (HMp), low (LMp)-methoxyl pectin, or gelatin. The secondary emulsions consisted of 2.5% SBO, 0.5% protein, and 0.2% polysaccharide or protein. Gelatin secondary emulsions were stable at pH 7 with defined droplets and became unstable at pH 5 and 3. The destabilization mechanisms for these emulsions at pH 5 and 3 were different as observed with the SEM: at pH 5 there is complete aggregation of protein due to their proximity to the isoelectric point; and at pH 3 the droplets are perfectly separated, suggesting that at this pH, when the net charge is positive, the destabilization is mainly due to depletion flocculation. HMp secondary emulsions shift from being stable (individual droplets) at pH 3 to being unstable at pH 7 where an extensive webbing is observed between the droplets at this pH value. The ι-carrageenan secondary emulsions are stable at each pH and the individual droplet microstructure is minimally altered as the pH changes. LMp secondary emulsions shift from being stable at pH 7 with individual droplets observed in the SEM micrographs to being unstable at pH 3 where extensive webbing is observed in the SEM micrographs.     

富锌豆蛋白中锌结合态含量的研究

富锌豆蛋白是一种用特殊科学方法得到的高含量锌添加剂。本文利用植物生化分离和分析方法,研究了富锌豆蛋白中锌与不同蛋白结合状态下的含量。分析结果显示,游离锌为150.7μg/g,结合于蛋白中的锌为1055.0μg/g。可以认为锌主要以有机蛋白锌的形式存在。     

Mechanism for maintaining blood protein composition with various protein regimens

The study of the blood plasma protein content, turnover constant and half-life of albumin, fibrinogen and the total fraction of IgG + transferrin, was conducted in 70 male Wistar rats which received rations containing 4, 8, 12, 18 and 36% protein (casein), during a month. The total serum protein content and the proteins assayed in the blood plasma were not reliably changed in relation to the protein level in the animals' ration. It was found that the half-life of the proteins studied increased with the lowering of the protein content in the ration. It is suggested that the increase of the blood plasma protein half-life is one of the mechanisms of maintaining stable blood plasma protein composition in case of insufficient protein content in the food ration.