摘要
研究了 2 0℃、相对湿度 80 %～ 90 %条件下黄花梨果实采后软化的生理生化变化。结果表明 ,黄花梨属于呼吸跃变型果实 ,采后果肉硬度逐渐下降而出汁率逐渐增加。采后 5d内淀粉酶活性增加 2 .9倍而淀粉含量下降 72 .80 % ,之后淀粉酶活性和淀粉含量逐渐下降。采后原果胶和纤维素含量下降而可溶性果胶含量增加 ,且果肉硬度同原果胶含量和纤维素含量都呈极显著正相关 (P <0 .0 1)。采后 5d内 ,多聚半乳糖醛酸酶 (PG)和纤维素酶活性变化不大 ,之后迅速上升 ,到采后 15d达到酶活性高峰 ,分别为采收时的 3.0倍和 7.9倍 ,之后酶活性逐渐下降。因而认为 ,黄花梨采后 5d内果肉软化 ,主要是淀粉酶活性的快速上升催化淀粉的快速水解造成的 ,并为呼吸跃变准备能源物质 ;之后果肉软化是由PG、纤维素酶作用引起果胶质、纤维素等细胞壁组分降解所致。
Postharvest physiological and biochemical changes of softened Huanghua Pear (Pyrus Pyrifolia Nakai cv. huanghua) fruit were investigated at 20℃ and 80%-90% RH. The results were as follows: the respiratory pattern of Huanghua pear belonged to climacteric fruit, flesh firmness gradually decreased but the flesh extractable juice content gradually increased. The amylase activity increased by 2.9 fold but the starch content decreased by 72.80 % within 5 days after harvest, then the amylase activity and starch content gradually decreased. The protopectin and cellulose content decreased but soluble pectin content increased, and both protopectin content and cellulose content were positively correlated with flesh firmness significantly(P<0.01). Polygalacturonase (PG) and cellulase activity had little changes within 5 days after harvest, then enzymic activity rapidly increased, and the enzymic activity peak appeared on the 15th day after harvest, PG activity increased by 3.0 fold and cellulase activity increased by 7.9 fold as compared with that at harvest day, then enzymic activity gradually decreased. It was suggested that flesh softening of Huanghua pear within 5 days after harvest was mainly caused by rapid degradation of starch, which was catalyzed by rapid increase of amylase activity. Energy substance was supplied by starch degradation for respiratory climacteric. Afterwards, flesh softening was caused by the degradation of cell wall components such as pectin and cellulose, which were brought about by the action of PG and cellulase.
出处
《中国农业科学》
CAS
CSCD
北大核心
2003年第3期349-352,共4页
Scientia Agricultura Sinica
基金
福建省教育厅科技资助项目 (K990 0 8)
关键词
采后
罗化生理
黄花梨
果肉软化
淀粉
细胞壁组分
淀粉酶
细胞壁降解酶
Huanghua pear(Pyrus pyrifolia Nakai cv. huanghua)
Flesh softening
Starch
Cell wall components
Amylase
Cell wall degrading enzyme
