化学改性大豆蛋白木材胶粘剂研究进展

该文综述大豆蛋白胶粘剂粘接及耐水机理、化学改性方法及改性大豆蛋白胶粘剂在秸秆板中应用情况;最后指出化学改性大豆蛋白木材胶粘剂存在问题及今后发展方向。     

生物质胶粘剂在人造板中的应用

分析了生物质胶粘剂在人造板中的应用现状,综述了近年来大豆蛋白基胶粘剂、淀粉基胶粘剂和木质素胶粘剂的研究进展.针对目前生物质胶粘剂在胶合强度、耐水性和改性工艺以及在人造板应用等方面存在的问题,笔者认为:应从生物质胶粘剂的宏观粘结特性和微观结构变化出发,深入研究其胶合机理并采用更有效的改性方法和生产工艺,使之广泛应用于人造板工业.     

基于改性大豆蛋白胶粘剂的刨花板性能研究

研究了改性大豆蛋白胶粘剂的流变特性及基于改性大豆蛋白胶粘剂的刨花板力学性能。结果表明。NaOH、十二烷基硫酸钠（SDS）及脲改性,均使大豆蛋白胶粘剂的黏度增大,NaOH和SDS的改性效果优于脲。相比于未改性的大豆蛋白胶粘剂刨花板,NaOH和SDS的改性明显提高了刨花板的静曲强度、弹性模量及抗拉强度,所制刨花板已达到美国标准ANSIA208,1中M—S级刨花板性能指标的要求。选用粒度范围为2-5mm的中刨花时,刨花板的力学性能最好,当刨花粒度过小（0-2mm）或过大（5-8mm）时,刨花板的力学性能指标均减小。基于NaOH改性大豆蛋白胶粘剂的木刨花板力学性能优于竹刨花板及稻秸刨花板。     

大豆蛋白改性产物乳化特性研究进展及其应用

大豆蛋白作为一种安全的乳化剂常被应用于食品乳化体系,通过物理法、酶法和化学法可诱导大豆蛋白的结构变化,改善大豆蛋白乳化性。本文将简要介绍改性大豆蛋白乳化能力及乳化稳定机理,分析影响乳化特性的因素。详细探讨物理法（热处理,超声法,高压处理）、酶法（水解酶,交联酶）和化学法（糖基化法）改性后大豆蛋白的乳化特性改善。最后针对大豆蛋白作为乳化剂在食品行业的应用与发展进行深入讨论。     

生物质胶粘剂的研发及在家具板材中的应用研究

随着全世界不可再生资源的日渐枯竭,利用大宗农产品等可再生资源生产环保型的绿色化工产品已经引起世界各国工业界的重视。本文从大豆蛋白的结构特性、改性方法等方面介绍了近年来大豆基木材胶粘剂的研究进展,并在此基础上以大豆粉为原料,采用综合改性手段进行处理,引入微胶囊形态的拟除虫菊酯类防虫剂,制备了大豆胶粘剂,同时进行应用研究。结果表明,经过改性后,大豆胶粘剂性能满足胶合板、生态细木工板等家具板材生产要求。     

挤压预处理酶解修饰大豆蛋白乳化特性的研究进展

大豆蛋白分子质量大、结构较紧密、油滴吸附速率较慢,因此乳化特性较低,不能满足其在现代食品加工中的应用需求。改善大豆蛋白的乳化特性成为目前的研究热点。本文综述了挤压预处理、酶解改性和挤压预处理联合酶解过程对大豆蛋白乳化特性作用的研究进展,并分析了大豆蛋白在不同改性过程中蛋白构象的变化、蛋白与蛋白之间的相互作用及乳化特性的改善情况,为研究挤压-酶解过程改善大豆蛋白乳化特性的机制及生产应用提供理论支撑。     

大豆蛋白改性研究的进展

大豆蛋白以其来源广、成本低、功能特性优异的特点而被人重视,通过对大豆蛋白改性可以提高其功能特性,拓宽大豆蛋白在食品工业中的应用。综述了大豆蛋白改性技术中物理改性、化学改性和酶法改性方面的研究进展,以期为大豆蛋白的高值化深加工和综合利用提供参考。     

醇法大豆浓缩蛋白物理改性研究

采用物理方法对大豆浓缩蛋白进行改性,在提高大豆浓缩蛋白溶解性条件下,得出物理改性最佳工艺条件为:温度100℃、pH值9.0、时间6min、蛋白质浓度1:9;测定改性前后大豆浓缩蛋白的NSI,乳化性,乳化稳定性等变化。结果表明,改性后大豆浓缩蛋白溶解性有明显增加,大豆蛋白功能特性均有不同程度提高和改善。     

大豆浓缩蛋白的改性

大豆蛋白的功能特性是由其特殊的分子结构所决定的。蛋白发生变性后，蛋白质的功能特性将发生改变。在一定条件下，大豆蛋白的变性过程是可逆的，利用这一可逆变性现象，探讨了大豆浓缩蛋白的改性过程，并对改性的关键技术进行控制，确定了改性的生产工艺。改性后的功能性大豆浓缩蛋白的功能特性有较好的改善。     

大豆11S球蛋白-麦芽糖共价改性及其凝胶流变特性

为提高大豆蛋白凝胶性,从低温脱脂豆粕中提取大豆11S球蛋白,添加麦芽糖对其进行湿法糖基化改性,运用Box-Behnken模型对改性条件进行优化,并分析了糖基化反应前后蛋白样品凝胶强度及流变学特性的变化。结果表明:在最优工艺条件为麦芽糖添加量1.85%,反应温度68.42℃,反应时间50.08 min下,凝胶强度可达269.43 g。根据实际情况,在麦芽糖添加量2.0%,反应温度70℃,反应时间50 min条件下进行验证实验,结果凝胶强度为270.52 g,相对偏差为0.4%,较未改性11S球蛋白提高了20.7%;改性前后蛋白质凝胶流变特性的分析结果显示,糖基化产物的凝胶弹性模量G’、黏性模量G"较大豆球蛋白单独体系均有所提高,凝胶形成点从2 648s提前到2 489 s,说明糖基化反应促进了大豆球蛋白凝胶网络结构的形成,改善了大豆球蛋白的凝胶特性。     

大豆蛋白胶黏剂制备过程中的黏度变化及其黏合性研究

运用Brabender黏度仪研究改性大豆分离蛋白(SPI)胶黏剂制备过程中的黏度变化,并对它们的黏合性进行了研究.结果发现:改性SPI胶黏剂制备过程中的黏度变化趋势大致相同;制备过程中,改性SPI胶黏剂的起始黏度随NaOH浓度的增加而增加,由90BU增加到550 BU,而尿素、三聚磷酸钠、Na3PO4对其影响较小;0.7%(WNaOH/WSPI)NaOH改性SPI胶黏剂的黏合性较好,其T剥离强度为140.8 g/cm,比未改性SPI胶黏剂增加了61.8%.     

Modified Soy Proteins with Improved Foaming and Water Hydration Properties

Soy proteins were modified by alkali treatment at pH 10.0, followed by papain hydrolysis. Solubility, water hydration capacity (WHC), surface hydrophobicity, foaming and emulsifying properties of unmodified, alkali-treated, and papain-modified soy protein (PMSP) were compared. PMSP exhibited higher solubility (100% at pH > 7.0), WHC (3.13) and hydrophobicity (40.8) than unmodified soy protein which had solubility 68.5%, WHC 0.21, and hydrophobicity 8.1. The PMSP had foaming capacity (22.0 mL) similar to egg white (21.2 mL) at pH 7.0; and enhanced foam stability (36.4) compared to the unmodified control (32.9). In general, alkali-treated soy had lower functional properties. Emulsifying properties of PMSP and alkali treated soy were unchanged by the modification. PMSP could be used as an egg white substitute in foaming applications at neutral pH.     

Partially Hydrolyzed Soy Protein Shows Enhanced Transport of Amino Acids Compared to Nonhydrolyzed Protein across an Intestinal Epithelial Cell Monolayer

Consumption of protein hydrolysates has been proposed to stimulate muscle anabolism more than intact (nonhydrolyzed) proteins via accelerated delivery of amino acids for muscle protein synthesis (MPS). We evaluated whether the rate of amino acid uptake and transport across intestinal cells was enhanced for soy protein hydrolysates versus nonhydrolyzed soy protein. Intact and partially hydrolyzed proteins were subject to simulated gut digestion and applied to the apical surface of Caco‐2 monolayers. Basolateral media was harvested after 3 h and quantitatively analyzed for free amino acids using ion‐exchange chromatography and comparison to an included reference standard. Basolateral concentrations of all amino acids were higher (mean 32%) for hydrolyzed versus nonhydrolyzed protein with the greatest differences in histidine, lysine, and valine. Scale‐up production of the soy protein hydrolysate did not diminish its enhanced absorption properties. These data support the hypothesis that hydrolyzed soy protein may provide dietary amino acids that are more rapidly transported across the intestinal epithelium versus intact soy protein. This would be important under conditions where rapid and increased levels of amino acids are needed such as in the stimulation of MPS.     

Effect of Lipophilization of Soy Protein on Its Emulsion Stabilizing Properties

Effect of lipophilization of the soy protein (SP) molecule on emulsion stabilizing properties (ES) was investigated by comparing the properties of alcohol-modified, acetylated, partially hydrolyzed and unmodified SP. The modified SPs showed high ES even in the slightly acidic region, where the protein solubility remained at low level, whereas the ES of unmodified SP decreased with the decrease of protein solubility. The hydrophile-lipophile balance (HLB) number of SP at pH 4.5 decreased and its ES increased as a result of modifications. Both the exposed tyrosine of SP determined by ultraviolet difference spectra and the hydrophobic region on the surface of the SP molecule compared with relative fluorescent intensity was increased by ethanol-modification. The ES of the modified SP were found to increase almost linearly with the increase in fluorescent intensity and intrinsic viscosity. Considering these facts and the nature of effect of alcohols on globular proteins, it was concluded that lipophilization of the SP molecule is one of the primary factors which increase the ES in the slightly acidic region.     

Physicochemical and in vitro digestion properties of soy isoflavones loaded whey protein nanoparticles using a pH-driven method

Soy isoflavones are widely used as a dietary supplement. However, the bioavailability of soy isoflavones is low due to the poor water solubility. Whey protein is an excellent biopolymer to encapsulate functional ingredients. In this study, soy isoflavones loaded whey protein nanoparticles were prepared using a pH-driven method. The physicochemical properties and in vitro digestion properties of the nanoparticles were investigated. The results showed that the physicochemical properties of nanoparticles were regulated by the mass ratios of soy isoflavones to whey proteins. Hydrogen bonding and hydrophobic interactions were confirmed in generating soy isoflavones loaded nanoparticles, which modified the thermal stability and secondary structure of whey proteins. The nanoparticles could pass through simulated gastric digestion to deliver soy isoflavones into the intestinal tract, responsible for the increased digestion stability and bioaccessibility of soy isoflavones. Moreover, the controlled release of soy isoflavones from nanoparticles can be achieved with a mechanism of non-Fickian diffusion. This study may provide useful information about the utilization of soy isoflavones loaded whey protein nanoparticles to develop functional foods.     

Rice Dreg Protein as an Alternative to Soy Protein Isolate: Comparison of Nutritional Properties

Rice dreg protein could be a valuable source of plant-based proteins, as an alternative to soy proteins in some food products. Here, nutritional properties of rice dreg protein were compared with those of soy protein isolate. The protein content of rice dreg protein was approximately 62.6 g/100 g sample, with large amounts of fat, carbohydrate, and ash. The denaturation temperatures of rice protein isolate from rice dreg protein were 47.4 and 97.2°C, respectively. This indicated that these proteins could be denatured during rice syrup processing to form aggregates, but were relatively more stable than rice endosperm protein and soy protein isolate. The main amino acids in rice dreg protein and rice protein isolate were Glu, Pro, Arg, Asp, and Leu, with Lys as the lowest content. Most of essential amino acids and nutritional parameters of rice protein isolate and rice dreg protein met the suggested nutritional requirements for a child according to FAO/WHO, and were relatively higher than those of soy protein isolate. In addition, rice protein isolate showed better digestibility than soy protein isolate during four hours sequential pepsin and pancreatin digestions. The final digestibility value was 96.66% for rice protein isolate compared to 91.41% for soy protein isolate. Thus rice dreg protein could potentially replace soy proteins as a good source of value-added protein for human nutrition in response to the increasing demand for plant proteins.     

蛋白质适度加工：热聚集与凝胶品质阐述以及过度聚集的调控对策

加热处理会引起肌肉蛋白质变性、聚集,最终使溶胶态蛋白质形成凝胶,其中聚集的速率、程度、形态和模式都会影响蛋白质凝胶的品质。我国传统的酱卤食品加热温度都不低于100 ℃,并且罐装食品一般采用二次加热的方式来延长货架期,这些都会导致蛋白质过度聚集,从而降低了水的流动性和蛋白质消化率,破坏了肉制品的品质,降低了产品的营养价值。本文通过Lumry-Eyring成核聚集（Lumry-Eyring nucleated polymerization,LENP）模型分析蛋白质聚集机制;阐释3 种蛋白质聚集模式,包括纤维聚集、水凝胶聚集以及无定形聚集。从蛋白质分子空间构象角度综述4 种过度热聚集行为的调控对策：pH值、氨基酸、多酚化合物、疏水型与还原型小分子能够有效抑制肌原纤维蛋白过度聚集,并改善热诱导蛋白质的凝胶性能;酪蛋白作为分子伴侣蛋白能够有效提高食品的热稳定性,降低蛋白质的聚集程度。综上,采用上述蛋白质聚集调控对策可以改善肉制品的凝胶和质构品质。     

大豆蛋白改性和黏合性研究

为解决石油生产的黏合刑的环境毒性问题，以大豆分离蛋白(SPI)为原料，经加热(H)、胰蛋白酶(T)、碱(A)、尿素(U)和盐酸胍(GH)改性，分别制得改性大豆蛋白H-SPI、T-SPI、A-SPI、U-SPI和GH-SPI。将其用作不同硬度木质的黏合剂，经试验测定表明它们的黏合强度和阻水性都优于未改性SPI。还对几种改性方法进行了比较，结果表明尿素改性和碱改性是比较好的两种方法。     

低温超微粉碎对豆渣蛋白结构及功能性质的影响

为研究低温超微粉碎对豆渣蛋白结构与功能性质的影响,明确低温超微粉碎对豆渣蛋白的作用机制。本文利用低温超微粉碎技术处理豆渣,采用荧光光谱法分析不同处理条件下豆渣蛋白的结构变化,并通过豆渣蛋白界面性质、溶解性、粒度分析及ζ-电位对其功能性质进行表征。结果表明:低温粉碎200目下豆渣蛋白性质最佳,其粒径分布稳定,体积平均粒径D_[4,3]降低至(24.06±0.02)μm,ζ-电位绝对值增大至14.02±0.02;通过荧光光谱分析可知,低温超微粉碎使得豆渣蛋白结构发生解折叠,蛋白分子内疏水性氨基酸暴露。     

Water‐soluble myofibrillar proteins prepared by high‐pressure homogenisation: a comparison study on the composition and functionality

To expand utilisation of meat in various products, the characterisation and functionalities of water‐soluble myofibrillar proteins (WSMP) induced by high‐pressure homogenisation (HPH) were determined by comparison with those of soy protein isolate (SPI) and whey protein isolate (WPI). WSMP had high contents of protein (87.40%), which was mainly composed of myosin, actin and tropomyosin. The essential amino acids of WSMP achieved the FAO/WHO/UNO (2007) standards for preschool children, and the contents of lysine and sulphur‐containing amino acids of WSMP were higher than those of SPI, making it desirable for children formulations. WSMP showed higher surface hydrophobicity while its water solubility was similar to that of SPI, but lower than that of WPI. WSMP demonstrated superior water/oil absorption capacities and emulsifying properties. The fibrous structure and high hydrophobic activity characteristics of WSMP were able to stabilise oil droplets with submicron droplet size, consequently responsible for its excellent emulsifying properties.