酸预处理对酶法骨明胶功能性质和分子质量分布的影响

本文以牛骨粉为原料,采用酶解法制备明胶,考察了骨粉预处理试剂——盐酸的浓度对明胶产品的冻力、粘度、分子量分布和等电点的影响.研究表明,随着骨粉预处理用的盐酸浓度的增大,明胶产率降低.骨粉经过盐酸预处理后,明胶产品的冻力大于300 bloom g,高于原料未经盐酸处理得到的明胶产品.与传统的碱法工艺明胶相比,酶法明胶具有高冻力、高等电点和相对较低的粘度等特点.采用聚丙烯酰胺凝胶电泳表征明胶的分子质量分布,酶法明胶不但具有传统碱法明胶具有的96 KDa、97 KDa、193 KDa和289 KDa组分,而且具有165 KDa和120 KDa组分.酶法明胶的等电点在碱性范围内,随着预处理用盐酸浓度的增大,明胶产品的等电点升高.骨料的预处理工艺对明胶的产率、冻力、粘度、等电点和分子质量分布有重要的影响,在明胶制备过程中,通过调控骨料预处理酸浓度可以调控明胶的技术指标.

Effect of Acid Pretreatment on IEP and Protein Patterns of Gelatin from the Bovine Bones by Protease-Conditioned Process

Gelatins were prepared from the bone pretreated using hydrochloride with various concentrations by protease-conditioned method in this article.The yields of protease-conditioned gelatin were decreased as the concentration of HCl was increased from 0 to 4.5%(mass fraction).The bloom values of protease-condition gelatin were all higher than 300 when the bovine bone were pretreated with HCl.Compared with commercial type B gelatin,protease-conditioned gelatin exhibited higher bloom strength,lower viscosity and higher IEP value.Compared with protein patterns of type B gelatin,different protein patterns of protease-conditioned gelatin were noticeable with the immersing of the new bands at the Mw of 165 KDa and 120 KDa.The IEPs of protease-conditioned gelatin were all in alkaline range which was related to the content of arginine.The results showed that the pretreatment process of bone was very important for protease-conditioned gelatin because the yield,viscosity and IEP were determined by the pretreatment condition.