碱性蛋白酶限制性酶解乳清浓缩蛋白成胶特性的研究

研究了利用碱性蛋白酶限制性酶解乳清蛋白对其凝胶特性、成胶温度、凝胶粒径和蛋白组分水解情况的影响,结果表明,酶解可以提高乳清蛋白的凝胶特性,在酶解70min时达到最大值,此时乳清蛋白的水解度为7．22％,当酶解时间超过70min后随着水解时间的延长凝胶特性略有下降;各水解时间点乳清蛋白成胶温度均为80℃;酶解后乳清蛋白凝胶的粒径值下降了90％以上,且酶解30min后形成的凝胶粒径值都在50um以内;在碱性蛋白酶的限制性酶解作用下,仅部分β-乳球蛋白和很少部分牛血清白蛋白被酶解,而大部分α-乳白蛋白被酶解。     

南极磷虾酶解工艺优化及模型建立

以短肽得率(trichloroacetic acid-nitrogen soluble index,TCA-NSI)和水解度(degree of hydrolysis, DH)为指标,从7种常用酶中选出Alcalase酶作为酶解南极磷虾的最适酶。对Alcalase酶水解南极磷虾的酶用量、底物浓度、pH值、温度和时间5个因素进行单因素试验和正交旋转组合试验,建立TCA-NSI和DH与各因素的回归模型;在此基础上,结合实际生产确定Alcalase酶水解南极磷虾的最适工艺为温度50.7℃、pH8.01、加酶量3010U/g、时间239min,此时TCA-NSI值为73.02%,DH值为42.33%,短肽平均肽链长(peptide chain long,PCL)为2.36,平均相对分子质量为277.9。     

碱性蛋白酶水解蚕蛹蛋白集总动力学

引言蚕蛹是养蚕业主要的副产物,蚕蛹蛋白质量占干蚕蛹质量的45%～50%。蚕蛹蛋白含有18种氨基酸,其中8种人体必需氨基酸含量占氨基酸总量40%以上,是一种优质蛋白源。文献报道蚕蛹蛋白酶解后的多肽具有抗氧化、降血压、抗疲劳、提高免疫力和抑制癌细胞扩散等作     

Immobilization of Alcalase on Silica Supports Modified with Carbosilane and PAMAM Dendrimers

Enzyme immobilization is a powerful strategy for enzyme stabilization and recyclability. Materials covered with multipoint molecules are very attractive for this goal, since the number of active moieties to attach the enzyme increases with respect to monofunctional linkers. This work evaluates different dendrimers supported on silica to immobilize a protease enzyme, Alcalase. Five different dendrimers were employed: two carbosilane (CBS) dendrimers of different generations (SiO₂-G₀Si-NH₂ and SiO₂-G₁Si-NH₂), a CBS dendrimer with a polyphenoxo core (SiO₂-G₁O₃-NH₂), and two commercial polyamidoamine (PAMAM) dendrimers of different generations (SiO₂-G₀PAMAM-NH₂ and SiO₂-G₁PAMAM-NH₂). The results were compared with a silica support modified with a monofunctional molecule (2-aminoethanethiol). The effect of the dendrimer generation, the immobilization conditions (immobilization time, Alcalase/SiO₂ ratio, and presence of Ca²⁺ ions), and the digestion conditions (temperature, time, amount of support, and stirring speed) on Alcalase activity has been evaluated. Enzyme immobilization and its activity were highly affected by the kind of dendrimer and its generation, observing the most favorable behavior with SiO₂-G₀PAMAM-NH₂. The enzyme immobilized on this support was used in two consecutive digestions and, unlike CBS supports, it did not retain peptides released in the digestion.     

Functional and Bioactive Properties of Quinoa Seed Protein Hydrolysates

ABSTRACT: Quinoa protein concentrate was hydrolyzed with alcalase to obtain a hydrolysate that was fractionated by ultrafiltration using 10000- and 5000-molecular-weight cutoff membranes. Functional properties of the protein concentrate, protein hydrolysate, and membrane permeates were compared at different pH values. Protein solubility of the hydrolysate and membrane permeates were significantly higher ( P = 0.05) than that of the protein concentrate. The protein concentrate had a significantly higher ( P = 0.05) emulsifying activity index than the protein hydrolysate and membrane permeates. Membrane fractionation of the protein hydrolysate into lower-molecular-weight pep tides significantly reduced ( P = 0.05) foaming properties, but it improved radical scavenging activity and the ability to inhibit the activity of angiotensin-converting enzyme.     

大豆分离蛋白水解物降血压活性的体外检测

采用Alcalase酶处理大豆分离蛋白,对产物及其层析组分的降血压活性进行研究,结果表明Alcalase酶处理大豆分离蛋白产物具有一定的降血压活性;通过分子筛层析分离后,所得小分子组分降血压活性较高;增加外切酶处理可以改善水解产物的口味,但与不加酶处理相比其降血压活性降低。