热处理对采后琯溪蜜柚果实汁胞粒化的影响及其与细胞壁代谢的关系

汁胞粒化是柚类果实采后主要的品质劣变现象.本实验以琯溪蜜柚果实为材料,研究热处理对果实贮藏期间品质的影响,探讨其抑制汁胞粒化的作用和适宜处理条件,并探究该抑制作用与细胞壁中木质素和细胞壁多糖代谢的关系.分别以35、42、49、56℃热水对琯溪蜜柚果实进行喷淋处理,根据果实冷藏期内汁胞粒化指数、水分质量分数、可溶性固形物...

Effect of Heat Treatment on Juice Sac Granulation of Harvested Guanxi Honey Pumelo (Citrus grandis (L.) Osbeck) Fruit and Its Association with Cell Wall Metabolism

Juice sac granulation is a major quality deterioration of harvested pumelo fruit. This study investigated the effect of heat treatment on the fruit quality of Guanxi honey pumelo during postharvest storage and its inhibitory effect on juice sac granulation, and explored the appropriate conditions. Furthermore, this study analyzed the correlation between the inhibitory effect and the metabolism of lignin synthesis and polysaccharide degradation in the cell wall. Spraying with 35, 42, 49 and 56 ℃ water was employed as postharvest handling. The appropriate temperature was selected based on the granulation index and the contents of moisture, total soluble solids and titratable acid during cold storage, and its impacts on the lignin content, lignin synthetic enzyme activities, cell wall polysaccharide contents and cell wall polysaccharide-degrading enzyme activities in fruit juice sacs were evaluated. The results suggested that compared with other treatments, spraying with water at 42 ℃ for 15 min effectively retarded the increase in juice sac granulation index and the decrease in moisture content, and maintained the contents of total soluble solids and titratable acid. Meanwhile, it suppressed the activity of phenylalnine ammonialyase, cinnamyl alcohol dehydrogenase and peroxidase in the juice sac, delaying the increase in lignin content; and inhibited the activities of cellulase, pectin methylesterase, polygalacturonase and β-galactosidase, delaying the increase in cellulose and hemicellulose contents, the decline in covalently bound pectin content and the accumulation of ion-soluble pectin and water-soluble pectin in the juice sac during storage. The above results indicated that spraying with water at 42 ℃ could retard juice sac granulation and maintain the quality of harvested Guanxi honey pumelo fruit, and the inhibitory effect on juice sac granulation might be associated with inhibited enzyme activities related to lignin synthesis and cell wall polysaccharide degradation, resulting in delayed juice sac fibration, lignification and pectin degradation, which maintained the cell wall composition and structure.