pH值、温度和金属离子对endo-PG降解香蕉果胶多糖的影响

Effects of pH, Temperatures and Metal Ions on the Degradation of Banana Pectin Polysaccharides by Polygalcturonase

摘要:

从香蕉果肉中分离出水溶性果胶多糖(WSP)和酸溶性果胶多糖(ASP)，探讨了pH值、温度、金属离子对内切多聚半乳糖醛酸酶(endo-PG)降解果胶多糖的影响。结果表明，pH 3.7~4.6较适于endoPG的作用。在相同pH值下，endo-PG对WSP的降解效应随香蕉果实的成熟逐渐增强，而对ASP则逐渐减弱；在20~40℃内，温度越高，endo-PG对WSP和ASP的降解作用越强。Ca2+、Cu2+、Mg2+和Fe3+可显著抑制endo-PG对果胶多糖的降解；而Fe2+和Mn2+则起显著的促进作用。pH值、温度、金属离子等共同调控了endo-PG对果胶多糖的降解作用。

Abstract:

Water-soluble pectin (WSP) and acid-soluble pectin (ASP) polysaccharides were isolated from pulp of banana at different mature stages, and then the effects of pH, temperatures and metal ions on the degradation of WSP and ASP caused by endopolygalcturonase (endo-PG) were studied. The results showed that the optimum pH of endo-PG was from 3.7 to 4.6. At the same pH, the degradation of WSP by endo-PG increased with banana maturity, but that of ASP decreased. The degradation of WSP and ASP by endo-PG increased with the temperature from 20℃ to 40℃. Moreover, Ca2+, Cu2+, Mg2+and Fe3+ inhibited significantly the degradation of WSP and ASP, but Fe2+and Mn2+ enhanced significantly. It was suggested that pH, temperatures and metal ions could cooperate the degradation of pectin polysaccharides of banana.