关键词: 非酶褐变, 贮藏, 5-甲基糠醛, 半干型荔枝干, 动力学

Abstract: Kinetics of non-enzymatic browning in hemi-dried litchi fruits during 11 weeks were investigated. Hemi-dried litchi fruits were stored at -20℃, 3℃ or 40℃. Color changes were assayed by browning index (A280nm, A420nm) and the CIE-Lab color system. Browning level of hemi-dried litchi fruits stored at different temperatures with vacuum and no-vacuum packages increased according to a zero-order reaction kinetic. Activation energy for it was 54.51 J/mol and 52.17 J/mol, respectively. And color formation(ΔE) followed zero-order reaction kinetic, too. Activation energy was 38.49 J/mol and 38.41J/mol, respectively. 5-(hydroxymethyl)-2-furfural(5-HMF) concentration, in hemi-dried litchi fruits ranged from 78.63 to 2050.49μg/5 g according to storage temperature changes. Package form was not the main factor of affecting color formation and 5-HMF accumulation during storage period of hemi-dried litchi fruits. Evaluated from the color of products, the hemi-dried litchi fruits would lose their commercial value when they are stored for over 4 weeks at room temperature.

Key words: non-enzymatic browning, storage, 5-HMF, hemi-dried litchi fruit, kinetics