限制性酶解法制备花生蛋白凝胶及其性质研究

发布时间：2018-04-02 23:08

  本文选题：花生蛋白　切入点：凝胶　出处：《沈阳农业大学》2017年硕士论文

【摘要】：近年来,以植物为主的食品及肉类替代品受到普遍关注。花生是我国最具国际竞争优势的出口农产品之一,其以独特的风味和较高的营养价值被广泛应用于食品工业。目前,我国大部分花生用于制油,其副产物花生粕中的蛋白质含量较高,但由于花生蛋白加工工艺的限制以及其功能性有待改善,花生粕的研究利用仍处于初级阶段。蛋白凝胶具有较高的粘度、弹性和保水性,常作为稳定剂或乳化剂应用在肉制品、谷物制品以及乳制品等食品工业中。目前有关花生蛋白凝胶的研究不多,在现有的研究中,大多是经高温热诱导或者辅以盐类或酸类凝固剂形成的凝胶。研究表明,碱性蛋白酶具有促使蛋白质形成交联网络结构的能力,但是在不添加任何凝固剂的条件下,利用此方法制备成花生蛋白凝胶的研究还未见报道。本研究以低变性脱脂花生粕为原料,经碱溶酸沉法提取花生分离蛋白,采用碱性蛋白酶对花生分离蛋白进行限制性酶解,制备花生蛋白凝胶,研究花生蛋白凝胶的物化性质及其结构变化,并探讨利用碱性蛋白酶限制性酶解制备花生蛋白凝胶的作用机理,研究结果如下:1.利用碱性蛋白酶对花生蛋白进行限制性酶解,能够使其在50℃～70℃的条件下形成凝胶,未经酶解处理的花生蛋白溶液在70℃以内无法形成凝胶。2.以花生蛋白凝胶的硬度为指标,通过单因素及响应面试验,得到制备花生蛋白凝胶的最佳工艺参数为:加酶量2.50 U/g,酶解温度60℃,酶解时间36 min,pH 8.21,在此条件下制备的花生蛋白凝胶硬度的实测值为1.35±0.02N。3.对花生蛋白凝胶的物化性质进行分析。流变试验、蠕变-恢复测试以及表观粘度测试结果表明,该花生蛋白凝胶具有典型的凝胶流变特性;电泳分析显示,经酶解处理后,伴花生球蛋白Ⅱ所在的电泳条带浓度显著降低;DSC结果表明,经酶解处理后,蛋白质的热稳定性显著升高,结构的有序性显著降低。4.对花生蛋白的二级结构进行分析。圆二色及红外光谱分析表明,酶处理会显著降低花生蛋白二级结构中α-螺旋的含量,显著增加β-折叠及无规则卷曲的含量,但对β-转角含量的影响不显著。5.对花生蛋白的三级结构进行分析。结果表明,花生蛋白凝胶形成的主要驱动力为疏水相互作用,其次为氢键,离子键不是主要的化学作用力;酶解后,花生蛋白的表面疏水性升高;荧光光谱的最大荧光波长发生红移;暴露巯基和总巯基含量显著增加,且两者的比值增大,蛋白质的解折叠程度增大。
[Abstract]:In recent years, plant-based food and meat substitutes have received widespread attention.Peanut is one of the most competitive international agricultural products in China. It is widely used in food industry with its unique flavor and high nutritional value.At present, most peanuts in China are used to make oil, and the protein content in peanut meal is high. However, due to the limitation of peanut protein processing technology and the improvement of its function, the research and utilization of peanut meal is still in the primary stage.Protein gels with high viscosity, elasticity and water retention are often used as stabilizers or emulsifiers in meat products, grain products, dairy products and other food industries.At present, there are few researches on peanut protein gel. In the present research, most of them are induced by high temperature heat or formed by salt or acid coagulant.The results show that alkaline protease has the ability to form cross-linking network structure of protein, but the preparation of peanut protein gel by this method without adding any coagulant has not been reported.In this study, peanut protein isolate was extracted from low denatured defatted peanut meal by alkaline lytic acid precipitation method. The protein was hydrolyzed by alkaline protease to prepare peanut protein gel.The physicochemical properties and structural changes of peanut protein gel were studied, and the mechanism of preparing peanut protein gel by alkaline protease restriction enzymatic hydrolysis was discussed. The results are as follows: 1.Using alkaline protease to hydrolyze peanut protein, it can form gel at 50 鈩，

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