不同热处理DDGS蛋白质营养价值及瘤胃降解特性与其分子结构的相关性研究

Study on the Relationship between Nutritional Value, Ruminal Degradation Characteristics and Molecular Structure of Protein in Different Heat-treated DDGS

试验旨在研究不同热处理干酒精糟及其可溶物(DDGS)蛋白质化学成分、康奈尔净碳水化合物-蛋白质体系(CNCPS)组分、瘤胃降解特性和小肠消化率与蛋白质分子结构的相关性。采用CNCPS、尼龙袋技术及三步体外法对不同热处理的DDGS营养价值进行评定,利用傅里叶变换红外光谱技术(FTIR)分析蛋白质分子结构的变化,进而探求它们之间的相关关系。结果表明:加热使DDGS瘤胃降解率和小肠消化率降低,使小肠可消化蛋白增加;不同热处理对DDGS蛋白质分子结构均有显著影响(P<0.05);蛋白质分子结构中的酰胺Ⅰ和酰胺Ⅱ带的峰高和峰面积、酰胺Ⅰ带和酰胺Ⅱ带峰高和峰面积的比值与DDGS中蛋白质的营养价值、瘤胃降解参数及小肠消化率存在显著相关关系(P<0.05)。可见,不同热处理对DDGS蛋白质分子结构、营养价值和瘤胃降解特性及小肠消化率均有影响,DDGS中蛋白质分子结构可以有效地估测蛋白质营养特性,并可利用FTIR光谱技术对DDGS营养价值及加热程度进行评定。

The aim of the experiment was to investigate the correlation between protein molecular structure and protein chemical compositions,CNCNPS compositions,ruminal degradability and intestinal digestibility in different heat-treated dried distillers grains with solubles(DDGS).Cornell net carbohydrate protein system,nylon bag technology and three-step in vitro method were used to evaluate the utilization value of different heat treated DDGS.Fourier transform infrared spectroscopy(FTIR)was used to analyze the changes of DDGS protein molecular structure,and then relationship between both was researched.The results showed that the heating reduced the ruminal degradability and intestinal digestibility of DDGS and increased the digestible protein in the intestine.Different heat treatments had a significant effect on the molecular structure of DDGS protein(P<0.05).The amide I band peak height,peak area,amide II band peak height,peak area,ratio of amide I band and amide II band peak height and peak area in protein molecular structure were significantly correlated to the nutritional value of protein in DDGS,ruminal degradation parameters and intestinal digestibility(P<0.05).In summary,heat treatments have an impact on the molecular structure,nutritional value,ruminal degradability and intestinal digestibility of protein.Protein molecular structure of DDGS can effectively estimate protein nutritional valu e,ruminal degradability,and small intestine digestibility.FTIR spectroscopy can be used to evaluate the nutritional value and heating degree of DDGS.