Effects of pH, temperatures and metal ions on the degradation of banana pectin polysaccharides by endo-polygalcturonase.

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.