Amino acid composition, molecular weight distribution and gel electrophoresis of walnut (Juglans regia L.) proteins and protein fractionations.
As a by-product of oil production, walnut proteins are considered as an additional source of plant protein for human food. To make full use of the protein resource, a comprehensive understanding of composition and characteristics of walnut proteins are required. Walnut proteins have been fractionated and characterized in this study. Amino acid composition, molecular weight distribution and gel electrophoresis of walnut proteins and protein fractionations were analyzed. The proteins were sequentially separated into four fractions according to their solubility. Glutelin was the main component of the protein extract. The content of glutelin, albumin, globulin and prolamin was about 72.06%, 7.54%, 15.67% and 4.73% respectively. Glutelin, albumin and globulin have a balanced content of essential amino acids, except for methionine, with respect to the FAO pattern recommended for adults. SDS-PAGE patterns of albumin, globulin and glutelin showed several polypeptides with molecular weights 14.4 to 66.2 kDa. The pattern of walnut proteins in two-dimension electrophoresis (2-DE) showed that the isoelectric point was mainly in the range of 4.8-6.8. The results of size exclusion chromatogram indicated molecular weight of the major components of walnut proteins were between 3.54 and 81.76 kDa.
Food College, Shihezi University, Shihezi 832003, Xinjiang, China. maoxiaoying99@163.com.
Xiaoying
X
Mao
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, China. yfeihua@163.com.
Yufei
Y
Hua
Food College, Shihezi University, Shihezi 832003, Xinjiang, China. cgg611@163.com.
Guogang
G
Chen
D000596:Amino Acids; D005591:Chemical Fractionation; D004591:Electrophoresis, Polyacrylamide Gel; D031324:Juglans / Q000378:metabolism*; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry*
D000596:Amino Acids; D010940:Plant Proteins