Factors influencing pectin alkaline de-esterification

Commercial high ester citrus pectin was used to produce low methoxy pectin(LMP), factors which impact the quality and yield of pectin were explored, including pectin precipitation method. The tested indexes included the galacturonic acid content, the degree of esterification(DE), the viscosity of pectin solution and the yield of LMP. The results showed that low temperature(4 ℃) not only could reduce the β-elimination reaction which will impact pectin quality but also keep the viscosity of the product at a high level. The optimum condition for pectin alkaline de-esterification were follows: temperature was kept at 4 ℃ for 30 min, while the pH was remained at 9.0. Then pectin was precipitated by addiding isopropanol, From which the galacturonic acid content of low ester pectin is 86.57% with DE 47.98%, 88.02%of yield. All of the tested indexes meet the standards of low methoxy pectin.