3个品种荔枝果汁贮藏过程中的非酶褐变机理研究

Research of the Mechanism of Non-enzymatic Browning by Three Varieties of Litchi Juice During Storage

以槐枝、双肩玉荷包、禾荔3个品种荔枝原汁为研究对象,探讨了荔枝汁贮藏期间发生美拉德反应的机理。结果表明:贮藏期间,各品种荔枝汁中的蔗糖含量不断减少,果糖和葡萄糖的含量则先增加后减少,在贮藏后期,葡萄糖的褐变速度高于果糖,更易发生美拉德反应;不同品种的荔枝汁所含氨基酸组分相同,但含量不同,丙氨酸含量最大,谷氨酸、丝氨酸、组氨酸、精氨酸、苯丙氨酸、赖氨酸损失较为明显,达到了80%以上,可能是参与美拉德反应的主要氨基酸,苏氨酸、脯氨酸、亮氨酸损失则较少;不同品种的荔枝汁在贮藏过程中5-羟甲基糠醛(5-HMF)含量先增加后减少,而色差值则一直增加,在贮藏前期(0～90d),各品种荔枝汁的5-HMF含量与色差值具有良好的相关性。

The juice of three varieties of lychees, Huai Zhi,Yu Hebao,He Li, were chosen as material to study the mechanism of Maillard Reaction of lychee juice during storage. The result showed that the content of sucrose in all varieties of lychee juice decreased gradually during the storage, while the content of fructose and glucose increased at the beginning and then decreased. In the late storage stage, glucose turned brown more quickly than fructose which lead Maillard Reaction more liable ; the components of amino acid in different varieties of lychee juice were the same, but with different contents of amino acid, the content of Alanine was the highest, the content of Glutamate, Serine, Histidine, Arginine, Phenylalanine, Lysineall decreased dramatically - up to 80%. This indicated that they were the main amino acids in the Maillard Reaction. The content of Threonine, Proline, Leucine were reduced less . The content of 5 -hydroxymethyl furfural （5 -HMF）in different varieties of lychee juice increased first and then decreased during the storage. The color difference increased continuously. At the initial period of storage （0 - 90d） , there was a good correlation between the content of 5 - HMF and the color difference.