热处理对牛初乳理化性质和功能性蛋白的影响

Effects of Heat Treatment on Colostrum Physicochemical Property and Functional Proteins

科学控制牛初乳的加工工艺参数对初乳产品的开发与加工具有重要意义。本试验旨在探究热处理条件对初乳理化性质和功能性蛋白的影响,本研究设置7种不同的热处理条件(55℃/30 min、55℃/60 min、60℃/30 min、60℃/60 min、63℃/30 min、63℃/60 min和72℃/15 s),探究热处理后初乳理化指标、微生物菌落数和免疫球蛋白IgG以及乳铁蛋白的变化规律。结果表明,63℃条件下处理30 min和60 min,以及在72℃条件下处理15 s,出现明显的蛋白凝块;72℃处理15 s后显著降低初乳密度、酸度、乳蛋白、非脂固形物(SNF)、总固形物(TS)、柠檬酸、酪蛋白和尿素等理化指标;本研究所有热处理条件均显著降低菌落总数,有效控制大肠菌群和金黄色葡萄球菌数;经本研究设置的热处理后初乳中IgG水平显著降低,乳铁蛋白含量不受影响。综上考虑,建议初乳热加工温度控制在63℃以下,并根据生产目的针对性控制热加工参数。本研究可为牛初乳加工工艺参数控制提供详实科学数据支持。

Scientific control of the processing parameters of bovine colostrum is of great significance to the development and processing of colostrum products.The purpose of this experiment is to explore the effects of heat treatment on the physicochemical properties and functional proteins of colostrum.In this study,seven different heat treatment conditions(55℃/30 min,55℃/60 min,60℃/30 min,60℃/60 min,63°C/30 min,63°C/60 min,and 72°C/15 s)were designed,and changes of colostrum physicochemical indexes,microbial colony count,immunoglobulin IgG and lactoferrin after heat treatment were analyzed.The results showed that after treatment at 63℃for 30 min and 60 min,and at 72℃for 15 s,obvious protein clots appeared;physical and chemical indicators such as TS,citric acid,casein and urea were all significantly decreased,all heat treatment conditions in this study significantly reduced the total plate count,effectively controlling the number of Bacillus coli and Staphylococcus aureus.The IgG level in colostrum was significantly reduced after the heat treatments used in this study while the lactoferrin content was not.In summary,it is recommended that the thermal processing temperature of colostrum be controlled below 63°C,and the thermal processing parameters should be controlled according to the production purpose.This study can provide detailed scientific data support for the process parameter control of bovine colostrum processing.