米渣发泡蛋白的理化性质及形态结构

比较并分析了米渣蛋白(RDP)、脱酰胺米渣蛋白(RDDP)、米渣发泡蛋白(RDFP)的理化性质及形态结构。结果表明在p H 2~12,RDP的溶解度较低,RDDP的溶解度在p H 2~4.5减小,在p H 4.5~12则增加,RDFP的溶解度均高于90%。与RDP相比,RDDP与RDFP的起泡力在p H 8~10分别增加39%与126%以上,且在p H 9.5时分别达到最高值56%和196%。RDP的乳化性稳定,RDDP先减小后增大,RDFP则一直增大。RDDP与RDFP的必需氨基酸总量分别比RDP减少8.29%与7.7%,疏水值分别增加9.14%与30%。RDP、RDDP、RDFP均存在糖蛋白和α-螺旋、β-折叠片等二级结构,且数量依次减少。RDP结构紧密,聚集呈球状,RDDP分裂为相对较小的块状聚集体,RDFP为大块片层结构。RDFP具有良好的发泡性,可以作为一种蛋白质发泡粉用于食品工业。

Physicochemical Properties and Morphological Structure of Rice Dreg Foaming Protein

In this study, physicochemical properties and morphological structure of rice dreg protein (RDP), rice dreg deamidizing protein (RDDP), and rice dreg foaming protein (RDFP) were investigated. Solubility of RDP was low and stable at pH 2~12, solubility of RDDP decreased at pH 2~4.5 and increased at pH 4.5~12, solubility of RDFP was more than 90%. Compared to RDP, foaming force of RDDP and RDFP increased more than 39% and 126% at pH 8~10, and reached maximum 56% and 196% at pH 9.5, respectively. Emulsibility of RDP was stable, and emulsibility of RDDP firstly decreased and then increased, while that of RDFP had been increasing. Total amount of essential amino acid of RDDP and RDFP decreased 8.29% and 7.7%, and the hydrophobicity increased 9.14% and 30.%, respectively.There are some glycoproteins and secondary structure for ?-helix and ?-strand in RDP, RDDP, and RDFP, and the quantity decreased successively. RDP presented closely aggregate ball, RDDP became much smaller clumpy aggregations, and RDFP was a large piece of layer structure. The results indicated that RDFP might be used as a promising protein foam powder ingredient in food industry due to excellent physicochemical properties.