基于果胶特性改变的罐藏黄桃质构软化机制

Mechanism for Texture Softening of Canned Yellow Peaches Based on Modification of Pectin Characteristics

为探究罐藏黄桃质构品质变化及形成机理,本实验以‘金童5号’黄桃为原料制备罐头,提取罐藏黄桃果胶组分,即水溶性果胶(water soluble pectin,WSP)、螯合性果胶(chelator-soluble pectin,CSP)和碱溶性果胶(carbonate-soluble pectin,NSP),深入分析加工过程中罐藏黄桃不同组分的果胶含量、甲酯化度(degree of methoxylation,DM)、乙酰化度(degreeofacetylation,DAc)、分子质量及结构官能团等特性变化规律,解析加工过程中多聚半乳糖醛酸酶(polygalacturonase,PG)和果胶甲基酯酶(pectin methyl-esterase,PME)的活力变化。结果表明:预煮及热杀菌处理能显著改变罐藏黄桃果肉的质构品质;相比较新鲜黄桃样品,经预煮和杀菌的罐藏黄桃果肉WSP和CSP含量上升,NSP含量无显著差异(P>0.05);WSP和CSP的DM均呈下降趋势,WSP的DAc显著降低(P<0.05),CSP分子质量先增加后减小。此外,傅里叶变换红外光谱结果与DM测定结果一致。追踪加工过程中果胶酶活性发现,PME经预煮及热杀菌后已被完全钝化,PG活力整体仍保持较高活性。经相关性分析可知,酶及各果胶组分与质构品质之间均呈现不同程度的相关性,明确加工过程中酶及果胶结构特性变化是影响罐藏黄桃质构形成机制的主要因素。本实验为后续生产高品质罐装黄桃、延长货架期等提供理论基础。

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.