摘要
大豆分离蛋白(SPI)与葡萄糖按质量比1∶1混合生成美拉德产物(MRPs),通过测定不同反应温度条件(70℃、80℃、90℃)、不同反应时间(0,1,2,3,4,5,6 h)的MRPs的游离氨基含量、褐变程度、还原能力、羟自由基清除能力、DPPH自由基清除能力、紫外光谱扫描分析和聚丙烯酰氨凝胶电泳(SDS-PAGE)等指标,探讨MRPs的抗氧化性及其形成机理。结果表明:随着反应时间的延长,MRPs中游离氨基含量逐渐减少(P<0.05)。反应褐变程度越大,MRPs的抗氧化性越高。随着反应温度的提高,MRPs的抗氧化性增强,其中90℃6 h MRPs具有最高的还原能力,比SPI还原能力高5.6倍;90℃5 h的MRPs羟自由基清除能力与SPI相比提高了1.69倍,其DPPH自由基清除能力高达68.55%,是SPI的DPPH自由基清除能力的3.67倍,紫外扫描结果表明:MRPs的色氨酸吸收峰强度随着反应时间的延长逐渐增强,而80℃和90℃6 h MRPs色氨酸吸收峰有明显减弱趋势。SDS-PAGE显示:随着反应的进行,MRPs的α′和α亚基条带逐渐变浅,并生成的大分子物质,发生聚集。大豆蛋白葡萄糖反应生成的MRPs具有很强的抗氧化性,其与蛋白结构的变化密切相关。
Maillard reaction products （MRPs） were prepared from soy protein isolate （SPI） and glucose （mass ratio=1∶1） by heating at 70 ℃,80 ℃ or 90 ℃ for 0-6 h.The reducing ability,hydroxyl radical scavenging ability and DPPH radical scavenging ability were determined to investigate antioxidant of MRPs.Moreover,the degree of browning,UV spectroscopy scan analysis and SDS-PAGE were studied to explore antioxidant mechanism of MRPs.The results showed that free amino group content of MRPs were significantly decreased （P〈0.05） as the reaction proceeded,the antioxidant activity of MRPs was enhanced with the increase degree browning.The oxidation resistance of MRPs were improved as the reaction temperature increased,it was proved that MRPs which is heated for 6 h at 90 ℃ has the maximum reducing power,which is 5.6 times higher than SPI.MRPs obtained for 5 h at 90 ℃ exhibited the highest hydroxyl radical scavenging （1.69-fold increase over SPI） and DPPH radical-scavenging activity （68.55% scavenging activity,a 3.67-fold increase over SPI）.UV scan demonstrated that tryptophan absorption peak intensity of MRPs showed a trend of increase with increasing reaction time,whereas tryptophan absorption peak of MRPs heated for 6 h at 80 ℃ and 90 ℃ decreased.Meanwhile,SDS-PAGE illustrated that SPI and glucose formed high molecular weight conjugates,and the α＇and α sub band becomes shallow gradually with the reaction of maillard.All in all,these results suggested that glycoprotein have antioxidant properties and there is a close relationship between oxidation resistance and the changes of protein structure.
出处
《中国食品学报》
EI
CAS
CSCD
北大核心
2017年第2期44-51,共8页
Journal of Chinese Institute Of Food Science and Technology
基金
国家高技术研究发展计划(2013AA102208)
黑龙江省博士后资助项目(LBH-Z11212)
关键词
大豆蛋白
美拉德反应
抗氧化
结构
机理
soybean
Maillard reaction
antioxidant
structure
mechanism
