关键词: 罐藏黄桃；加工过程；预煮；杀菌；质构；果胶

Abstract: This paper aimed to explore the changes and formation mechanism of the texture quality of canned yellow peaches. Water soluble pectin (WSP), chelator-soluble pectin (CSP) and carbonate-soluble pectin (NSP) were extracted from canned yellow peaches made from the ‘Goldbaby 5’ cultivar. The pattern of changes in the contents of these pectin components and their characteristics such as degree of methoxylation (DM), degree of acetylation (DAc), molecular mass and chemical functional groups was investigated during the processing of canned yellow peaches, and changes in the activity of polygalacturonase (PG) and pectin methyl-esterase (PME) were also examined. Results demonstrated that precooking and subsequent sterilization could alter the texture quality of canned yellow peaches, leading to an increase in the contents of WSP and CSP but no significant difference in the content of NSP (P > 0.05) compared with fresh yellow peaches. The DM of WSP and CSP decreased, the DAc of WSP significantly decreased (P < 0.05), and the molecular mass of CSP increased after precooking and then decreased after subsequent sterilization. Additionally, infrared spectral analysis was consistent with DM measurement. PME was totally inactivated after sequential precooking and sterilization, while PG activity remained at a high level. The correlation analysis showed that the enzyme activities and the pectin components were differently correlated with the texture quality. It was clear that the changes in the enzyme activities and pectin structure characteristics during processing were the main factor affecting the mechanism for the texture formation of canned yellow peaches. These results provide a theoretical basis for the development of high-quality canned yellow peach with prolonged shelf life in the future.

Key words: canned yellow peaches; processing; precooking; sterilization; texture; pectin