热处理对驼乳、牛乳和山羊乳中氨基酸组成与含量的影响

Effect of different heat treatment on the amino acid composition and content in camel,cow and goat milk

为探究不同热处理条件对驼乳、牛乳和山羊乳中氨基酸组成的影响,该研究以新鲜驼乳、牛乳和山羊乳为原料,基于HPLC技术,检测低温长时巴氏杀菌(low temperature long time,LTLT)、高温短时杀菌(high temperature short time,HTST)和超高温瞬时灭菌(ultra high temperature,UHT)对3种畜乳中氨基酸组成和含量的影响。结果表明,通过HPLC可以很好地检测到3种乳中的17种氨基酸,且色谱峰形尖锐、无杂峰干扰。未处理组的聚类和主成分分析结果显示,相比牛乳,驼乳和山羊乳在氨基酸组成上更相近。对氨基酸组成的分析发现,未经处理和加热处理的驼乳、牛乳和山羊乳中氨基酸含量差异显著;未经处理的3种乳中必需氨基酸总量(essential amino acid,EAA)/氨基酸总量(total amino acid,TAA)和EAA/非必需氨基酸总量(non essential amino acid,NEAA)均达到了联合国粮农组织(Food and Agriculture Organization of the United Nations,FAO)/世界卫生组织(World Health Organization,WHO)理想蛋白相应指标,而加热处理对不同乳中EAA/TAA和EAA/NEAA具有不同的影响。UHT处理的牛乳和山羊乳中氨基酸的组成差异较大;而相比牛乳和山羊乳,3种热处理条件对驼乳中氨基酸含量的影响较低。同时,热处理会不同程度地增加3种乳中的Glu、Asp、Met和Cys的含量,进而增加乳香味、提高产品的风味。

The current research aimed to explore the effects of different heat treatment conditions,including low temperature long time(LTLT),high temperature short time(HTST),and ultra-high temperature(UHT),on the amino acid composition of camel,cow,and goat milk by HPLC,respectively.The results showed that 17 kinds of amino acids in camel,cow and goat milk could be detected by HPLC,and the chromatographic peak shape was sharp without the interference of miscellaneous peaks.Cluster and principal component analysis showed that compared with cow milk,camel milk and goat milk were more similar in amino acid composition.The amino acid content(mg/g) of camel,cow and goat milk was significantly different under the condition of no treatment and heating treatment.In raw milk,the essential amino acids(EAA)/total amino acids(TAA) and EAA/non-essential amino acids(NEAA) reached the corresponding indexes of Food and Agriculture Organization of the United Nations(FAO)/World Health Organization(WHO) ideal protein,while heating treatment had different effects on the content of EAA/TAA and EAA/NEAA in camel,cow,and goat milk.The composition of amino acids was different in cow and goat milk after UHT treatment;compared with cow and goat milk,the effect of heating treatment on the amino acid content of camel milk was low.At the same time,heat treatment could increase the content of Glu,Asp,Met and Cys,and therefore enriched the flavor.