摘要
为了评价褐变的发生对葡萄营养与功能活性的影响,跟踪考察无核白葡萄在30℃热风干燥过程中的色度、总酚含量及DPPH自由基清除能力、ABTS+.清除能力和还原能力等抗氧化活性的变化。结果表明:无核白葡萄在干燥的第8天开始出现明显的褐变,之后随着干燥时间的延长褐变程度不断加深,表现为红值(a*)上升,亮度值(L*)、黄值(b*)和色彩饱和度(c*)下降;干燥过程中,葡萄果实中总酚含量和抗氧化活性均呈总体下降趋势,但在第8天时有突然增大,之后又迅速下降;第8天时总酚含量的突然增大与葡萄开始褐变和红值(a*)峰值的出现时间相吻合;整个干燥过程中的总酚含量与3种抗氧化活性评价结果之间呈极显著正相关。这些现象说明,无核白葡萄中总酚是赋予其抗氧化活性的主要物质,褐变程度的加深会导致葡萄中总酚含量和抗氧化活性的下降。
Browning is an unavoidable problem during hot-air drying of Thompson seedless grape.In order to evaluate the influence of browning on nutritive and functional properties of raisin,we investigated the changes in color,total phenol content,and antioxidant properties such as DPPH,ABTS＋· scavenging capacity and reducing power during hot-air drying（30 ℃） of Thompson seedless grapes.The browning of Thompson seedless grapes started on the 8th day of drying and then became serious with increasing drying time;as a result,an increase in a＊ value and a decrease in L＊ value,b＊ value and c＊ value were observed.Total polyphenol content showed an overall decrease despite the sudden increase on the 8th day followed by a dramatic decrease.This increase on the 8th day corresponded to the time of appearance of browning and a＊ peak.During the entire drying process,total polyphenol content was extremely significantly positively correlated with DPPH,ABTS＋· scavenging capacity and reducing power.This finding indicates that total polyphenols are mainly responsible for the antioxidant activity of Thompson seedless grapes,and the observed decrease in total polyphenol content and antioxidant activity is related to aggregated browning.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2013年第5期55-59,共5页
Food Science
基金
国家现代农业(葡萄)产业技术体系建设专项(nycytx-30-ch-03)
关键词
无核白
热风干燥
总酚
抗氧化活性
颜色
thompson seedless
hot-air drying
polyphenol
antioxidant activity
color
