摘要
旨在分析牛羊鲜乳冷藏过程中蛋白质沉淀率变化及粒度大小。通过离心沉淀、原子力显微镜、激光粒度分析仪、SDS-PAGE电泳分析牛羊鲜乳冷藏过程中蛋白质沉淀率变化、鲜乳蛋白质粒子形貌、粒径分布范围、酪蛋白组成。结果表明:羊乳蛋白质沉淀率显著高于牛乳;牛乳蛋白质粒子数目(45μL^(-1))、密度(1.8μm^(-2))低于羊乳蛋白粒子数目(437μL^(-1))、密度(17.48μm^(-2));牛乳蛋白粒度大小主要集中在1nm以下,羊乳蛋白粒度只有19.3%在1nm以下,主要分布在1~1 000nm,其中100nm左右最多;牛羊乳酪蛋白主要有β酪蛋白和αs1酪蛋白2种,分子质量分别为34ku和26ku左右。牛乳蛋白质冷藏稳定性显著高于羊乳,羊乳蛋白质颗粒直径大于牛乳,牛羊乳蛋白质粒子数目和大小是影响冷藏稳定性差异的主要因素;原子力显微镜结合激光粒度仪是分析乳蛋白粒度大小的有效手段。
In this paper, protein sedimentation rate changes of milk from cow and goat during cold storage and their particles size were explored. Particle morphology, particle size distribution, casein composition of protein from fresh milk of cow and goat were analyzed by centrifugal sedimentation, atomic force microscope,laser particle size analyzer, and SDS-PAGE electrophoresis, respectively. The results showed that the sedimentation rate of goat milk protein was significantly higher than that of cow milk. The count of cow milk protein particles （45μL^-1） ,and density （1.8 μm^-2） were lower than those （437 μL^-1 and 17.48μm^-2 respectively） of goat milk. Goat milk protein particle size was mainly in less than 1 nm range,however,the same size was only 19.3% in cow milk,and mainly distributed in 1-1 000 nm range,and focused on 100 nm. Beta casein and alpha s1- casein were two main kinds of casein in cow and goat milk,with molecular weight of 34 ku and 26 ku respectively. Storage stability of cow milk protein was significantly higher than that of goat. Cow milk protein particles diameter was larger than that of goat milk, and the milk protein particles count and their sizes were the main factors on milk protein cold storage stability. Atomic force microscopy combined with laser particle size analyzer is an effective method to analyze the particle size of milk protein.
出处
《西北农业学报》
CAS
CSCD
北大核心
2016年第8期1144-1149,共6页
Acta Agriculturae Boreali-occidentalis Sinica
基金
陕西省科学技术发展计划(2014K13-20
2011K01-09)
国家科技支撑计划(2012BAD12B07)
陕西省自然科学基金(2007C127)~~
关键词
牛乳
羊乳
蛋白质
沉淀率
粒度
Cow milk
Goat milk
Protein
Sedimentation rate
Particles size
