Du Yanxue, Shi Suhua, Jiang Yan, Xiong Hua, Woo Meng Wai, Zhao Qiang, Bai Chunqing, Zhou Qiang, Sun Wenjing
State Key Laboratory of Food Science and Technology, Nanchang University, Jiangxi 330047, People's Republic of China.
J Sci Food Agric. 2013 Jan 15;93(1):125-33. doi: 10.1002/jsfa.5739. Epub 2012 Jun 6.
Rice dreg is an underutilized source of cereal protein with good potential for application in the food industry. Glutelin represents about 850 g kg(-1) of total storage protein in rice dreg. The objective of this study was to characterize the physicochemical properties and emulsion stabilization of the Maillard type conjugate formed with rice dreg glutelin (RDG) and κ-carrageenan (1:2 weight ratio) dry-heated at 60 °C and 79% relative humidity for 24 h.
Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Fourier transform-infrared analysis provided evidence on the formation of the Maillard type conjugation. Amino acid analysis suggested that the major locus during the Maillard reaction were lysine and arginine. Circular dichroism spectra showed decreasing amounts of α-helix and β-strand in the products with increment in the amount of turns and random coil. Conjugation with κ-carrageenan could significantly improve solubility of RDG (P < 0.05). Measurements of mean droplet size and creaming stability in oil-in-water emulsions showed that the conjugate was more effective at stabilizing emulsions at low pH or in the presence of high ionic strength.
The Maillard reaction can be successfully used as a coupling method for RDG and κ-carrageenan to form the conjugate with improved solubility and emulsion stabilization.
米渣是一种未得到充分利用的谷物蛋白来源，在食品工业中具有良好的应用潜力。谷蛋白约占米渣总贮藏蛋白的850 g/kg。本研究的目的是表征米渣谷蛋白（RDG）与κ-卡拉胶（重量比1:2）在60℃和79%相对湿度下干热24 h形成的美拉德型共轭物的理化性质和乳化稳定性。
十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和傅里叶变换红外分析为美拉德型共轭物的形成提供了证据。氨基酸分析表明，美拉德反应的主要位点是赖氨酸和精氨酸。圆二色光谱显示，随着转角和无规卷曲数量的增加，产物中α-螺旋和β-链的数量减少。与κ-卡拉胶共轭可显著提高RDG的溶解度（P<0.05）。水包油乳液中平均液滴尺寸和乳析稳定性的测量结果表明，该共轭物在低pH值或高离子强度存在下对乳液的稳定效果更佳。
美拉德反应可成功用作RDG与κ-卡拉胶的偶联方法，以形成具有改善的溶解度和乳化稳定性的共轭物。
