Analysis of resistant starch degradation in postharvest ripening of two banana cultivars: Focus on starch structure and amylases
Analysis of resistant starch degradation in postharvest ripening of two banana cultivars: Focus on starch structure and amylases
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两个香蕉品种采后成熟过程中抗性淀粉降解分析：重点关注淀粉结构和淀粉酶
DOI：
10.1016/j.postharvbio.2016.03.022
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发表时间：
2016-09-01
影响因子：
7
通讯作者：
Yi, Ganjun
中科院分区：
文献类型：
--
作者：
Gao, Huijun;Huang, Shaobo;Yi, Ganjun
香蕉是众所周知的良好的饮食能量来源，含有大量的糖和淀粉。为了进一步分析香蕉淀粉的降解机理，以卡文迪什和车前草两种香蕉为材料，研究了水解酶和颗粒结构对淀粉降解的影响。抗性淀粉(RS)、非抗性淀粉(Non-RS)、总淀粉和直链淀粉含量的测定表明，在果实成熟过程中，卡文迪什和车前草的各淀粉组分含量均逐渐下降。与卡文迪什相比，车前草的总淀粉和粗淀粉含量较高，淀粉降解速度较快，粗淀粉/总淀粉比值的下降幅度较小。扫描电子显微镜(SEM)图像显示，卡文迪什的淀粉粒较大且较圆，而车前草的淀粉粒较小且呈椭圆形。此外，基因表达分析表明，β-淀粉酶对这两个物种的淀粉降解起着核心作用，高度上调的β-淀粉酶与车前草中较快的淀粉降解速度相关。两种α-淀粉酶、一种淀粉磷酸化酶和一种淀粉去支化酶在车前草中特异上调，可能比卡文迪什更能降解非RS。(C)2016年，由爱思唯尔出版。
Bananas are well known as good sources of dietary energy, with high levels of sugar and starch. To further analyze the starch-degradation mechanism in bananas, two species, Cavendish and Plantain, were used to investigate the influences of hydrolases and granule structure on starch degradation. Determination of the levels of resistant starch (RS), non-resistant starch (non-RS), total starch, and amylose content showed that each starch component content decreased gradually during the fruit-ripening process in both Cavendish and Plantain. Compared to Cavendish, Plantain had a higher content of total starch and RS, a faster starch-degradation rate, and a lower decrease in the ratio of RS/total starch. Scanning electron microscopy (SEM) images revealed that the starch granules of Cavendish were larger and more rounded than the smaller and ellipsoidal starch granules found in Plantain. Also, the analysis of gene expression suggested that beta-amylases make a central contribution to starch degradation in both species and highly up-regulated beta-amylases were correlated with the faster starch-degradation rate in Plantain. Two alpha-amylases, one starch phosphorylase, and one starch debranching enzyme were specifically upregulated in Plantain, which might hydrolyse more non-RS compared with Cavendish. (C) 2016 Published by Elsevier B.V.