脱脂油棕谷蛋白2的营养价值与功能特性

Nutritional Value and Functional Properties of Defatted Oil Palm Glutelin-2

为促进油棕蛋白在食品中的应用,本试验对油棕谷蛋白-2的营养价值和功能特性展开研究。首先采用逐步提取法从脱脂油棕中提取谷蛋白-2,测定其氨基酸组成、体外消化吸收率、生物价、乳化性和黏度。结果表明,脱脂油棕谷蛋白-2中必需氨基酸总含量(48.65 g/100 g)显著(P<0.05)高于FAO/WHO的推荐值(12.7 g/100 g),其含硫氨基酸(半胱氨酸+甲硫氨酸)、支链氨基酸(亮氨酸、异亮氨酸)和天冬酰胺的含量也较高。此外,脱脂油棕谷蛋白-2的生物价为63.03,体外消化吸收率为70.02 g/100 g,因此其营养价值较高。Bigelow参数分析表明,脱脂油棕谷蛋白-2中极性氨基酸与非极性氨基酸的比值为2.18,表面疏水性为37.29。SDS-PAGE分析表明,脱脂油棕谷蛋白-2的分子量为22.1~133.5 kDa,主要由5个亚基组成,且亚基之间有二硫键。功能特性分析表明,脱脂油棕谷蛋白-2的乳化性(251.58±5.28)m2/g和乳化稳定性(84.40%)很高,显著(P<0.05)高于大豆分离蛋白(32.57 m2/g);其泡沫稳定性(17.61%)和黏度(21.33 cP)与大豆分离蛋白接近。本试验结果表明脱脂油棕谷蛋白-2的营养价值较高、功能特性较好,具有开发为营养强化剂、乳化剂、增稠剂等产品的潜力。

To promote the usage of oil palm in food industry,the nutrition value and functional properties of glutelin-2 were studied in this paper.The glutelin-2 was extracted from defatted oil palm with stepwise extraction method,and its amino acid composition,in vitro digestibility and biological value,emulsifying property and viscosity were studied.Results showed that the contents of total essential amino acid(48.65 g/100 g)of defatted oil palm glutelin-2(DOPG-2)was much higher than the standard recommend by FAO/WHO(12.7 g/100 g,P<0.05),and the contents of sulphur-containing amino acid,branched amino acids and asparagines were all high.Moreover,the biological value and in vitro digestibility of DOPG-2 were 63.03 and 70.02 g/100 g,respectively.It meant that the nutritional value of DOPG-2 was high.Result of Bigelow parameters analysis demonstrated that the ratio of polar side chains to nonpolar side chains of DOPG-2 was 2.18,and its surface hydrophobicity was 37.29.SDS-PAGE analysis showed that there were 5 subunits with mlecular weight of 22.1~133.5 kDa,and some disulfide bonds in DOPG-2.Furthermore,DOPG-2 exhibit significant higher emulsifier capacity(251.58±5.28)m2/g and emulsion stability(84.40%)than that of soy protein isolate(32.57 m2/g).And its foam stability(17.61%)and viscosity(21.33 cp)were similar with that of soy protein isolate.These results indicated that DOPG-2 had relatively high nutritional value and functional properties,could be used as a nutrient enhancer,emulsifier,thickener and other products.