Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Department of Horticulture, Foshan University, Foshan 528000, China; Tasmanian Institute of Agriculture, College of Science and Engineering, University of Tasmania, Hobart, Tas 7001, Australia.
Food Chem. 2023 Feb 15;402:134289. doi: 10.1016/j.foodchem.2022.134289. Epub 2022 Sep 17.
Water-soluble polysaccharides (WSP) were extracted from the pulp of litchi. Its main component was identified as arabinogalactan. The dominant monosaccharide constituents were arabinose and galactose. Galactose and mannose accumulated at the end of storage. ATP, ADP and AMP levels declined with increasing pulp breakdown index. WSP depolymerized which was characterized by a decrease in its content and molecular weight, while its structure remained stable during storage. Polygalacturonase and pectate lyase (PL) were active at the early storage time, and β-galactosidase (GAL) and α-l-arabinofuranosidase followed thereafter. Except for some pectin methylesterase (LcPME), LcPL, LcGAL and LcPME gene expression was downregulated. It was deduced that depolymerization of polysaccharides was mainly caused by the rupture of the branched side chain and glacturonic acid backbone to smaller repeating units, and both cell wall-degrading enzymes and nonenzymatic factors, such as energy level, participated in the degradation of polysaccharides, and consequently pulp breakdown of litchi.
从荔枝果肉中提取出水溶性多糖（WSP）。其主要成分为阿拉伯半乳聚糖。其主要单糖组成为阿拉伯糖和半乳糖。半乳糖和甘露糖在贮藏末期积累。随着果肉破碎指数的增加，ATP、ADP 和 AMP 水平下降。WSP 解聚，其含量和分子量下降，而其结构在贮藏过程中保持稳定。聚半乳糖醛酸酶和果胶裂解酶（PL）在贮藏早期活跃，随后β-半乳糖苷酶（GAL）和α-L-阿拉伯呋喃糖苷酶也活跃。除了一些果胶甲酯酶（LcPME）、LcPL、LcGAL 和 LcPME 基因表达下调。推断多糖的解聚主要是由于支链侧链和半乳糖醛酸主链断裂成较小的重复单元，细胞壁降解酶和非酶因素，如能量水平，参与了多糖的降解，从而导致荔枝果肉的破碎。
