不同品种梨汁贮藏过程中美拉德反应特性

Study on non-enzymatic browning of pear juice of different cultivars in storage

【目的】探明不同品种梨汁贮藏过程中美拉德反应特性。【方法】以10个梨品种果汁为试验材料,研究了不同品种梨汁在贮藏过程中非酶促褐变及其相关物质的变化规律。【结果】25℃贮藏条件下,1~35 d范围内,不同品种梨汁随着贮藏期的延长,褐变度都表现为升高趋势,并且在贮藏前期加速上升,后期趋于平缓;且‘丰水’梨汁的褐变度最严重,‘大核白’梨汁的褐变度最轻。在贮藏过程中,果汁中的5-HMF含量显著升高;pH值和氨态氮含量呈下降趋势;可溶性固形物含量变化无明显的规律;还原糖含量则呈先升高后降低的趋势,但最终含量比初始含量有不同程度的升高。相关性分析表明,5-HMF还原糖含量与梨汁褐变度呈正相关,pH值、可溶性固形物和氨态氮含量与梨汁褐变度呈负相关。【结论】‘细把清水’和‘馨香’梨汁的耐贮性好,且在贮藏过程中梨汁的感官品质和营养品质变化不大,是适合贮藏加工的优良品种。

【Objective】To explain the characteristics of Maillard reaction with pear juice of different varieties during storage.【Method】The 10 cultivars were used as experimental materials to study the changes of main materials of non-enzymatic browning in pear juice.【Result】Results showed the browning degree of different pear juice rose all together during storage time at 25 ℃.The browning degree rose fast at the earlier stage and rose smoothly at the later stage.‘Housui' was most seriously browning and‘dahebai' was the least browning after storing 35 d at 25 ℃.The 5-HMF content of 10 cultivar juice increased significantly during storage;the value of pH and the ammoniacal nitrogen content of of 10 cultivar juices decreased during storage;the TSS content of 10 cultivar juices changed irregularly during storage;reducing sugar content of juices of 10 cultivars increased early and decreased finally.The 5-HMF and reducing sugar content had positive correlation with browning degree;the value of pH,TSS and ammoniacal nitrogen content had passive correlation with browning degree.【Conclusion】The pear juice of ‘Xibaqingshui' and ‘Xinxiang' were good for storage,and the pear juice of sensory quality and nutritional quality changed less than other varieties during stored,they were excellent varieties for storage.