Tang Chuan-He, Ten Zi, Wang Xian-Sheng, Yang Xiao-Quan
Department of Food Science and Technology, South China University of Technology, Guangzhou 510640, People's Republic of China.
J Agric Food Chem. 2006 Nov 15;54(23):8945-50. doi: 10.1021/jf0619176.
The amino acid composition and physicochemical and functional properties of hemp (Cannabis sativa L.) protein isolate (HPI) were evaluated and compared with those of soy protein isolate (SPI). Edestin, a kind of hexameric legumin, was the major protein component. HPI had similar or higher levels of essential amino acids (except lysine), in comparison to those amino acids of SPI. The essential amino acids in HPI (except lysine and sulfur-containing amino acids) are sufficient for the FAO/WHO suggested requirements for 2-5 year old children. The protein solubility (PS) of HPI was lower than that of SPI at pH less than 8.0 but similar at above pH 8.0. HPI contained much higher free sulfhydryl (SH) content than SPI. Differential scanning calorimetry analysis showed that HPI had only one endothermic peak with denaturation temperature (T(d)) of about 95.0 degrees C, attributed to the edestin component. The T(d) of the endotherm was nearly unaffected by 20-40 mM sodium dodecyl sulfate but significantly decreased by 20 mM dithiothreitol (P < 0.05). The emulsifying activity index, emulsion stability index, and water-holding capacity of HPI were much lower than those of SPI, and the fat adsorption capacity was similar. The data suggest that HPI can be used as a valuable source of nutrition for infants and children but has poor functional properties when compared with SPI. The poor functional properties of HPI have been largely attributed to the formation of covalent disulfide bonds between individual proteins and subsequent aggregation at neutral or acidic pH, due to its high free sulfhydryl content from sulfur-containing amino acids.
对大麻（Cannabis sativa L.）分离蛋白（HPI）的氨基酸组成、理化性质和功能特性进行了评估，并与大豆分离蛋白（SPI）进行了比较。麻仁球蛋白是一种六聚体豆球蛋白，是主要的蛋白质成分。与SPI的氨基酸相比，HPI的必需氨基酸（赖氨酸除外）含量相似或更高。HPI中的必需氨基酸（赖氨酸和含硫氨基酸除外）足以满足粮农组织/世界卫生组织对2至5岁儿童的建议需求量。在pH小于8.0时，HPI的蛋白质溶解度（PS）低于SPI，但在pH高于8.0时相似。HPI的游离巯基（SH）含量比SPI高得多。差示扫描量热法分析表明，HPI只有一个变性温度（T(d)）约为95.0℃的吸热峰，归因于麻仁球蛋白成分。该吸热峰的T(d)几乎不受20 - 40 mM十二烷基硫酸钠的影响，但在20 mM二硫苏糖醇作用下显著降低（P < 0.05）。HPI的乳化活性指数、乳化稳定性指数和持水能力远低于SPI，脂肪吸附能力相似。数据表明，HPI可作为婴幼儿和儿童宝贵的营养来源，但与SPI相比功能特性较差。HPI功能特性较差主要归因于单个蛋白质之间形成共价二硫键以及随后在中性或酸性pH下的聚集，这是由于其含硫氨基酸的游离巯基含量高。
