ペクチン質の誘導体に関する研究(第1報)

メタノール-塩酸-水系におけるペクチン酸およびペクチニソ酸のメチルエステル化

抄録

A new procedure is described for the methyl-esterification of pectic and low-methoxyl pectinic acids using the mixture of methanol, hydrochloric acid and water.
Pectic and low-methoxyl pectinic acids were readily esterified with 80 or 90% methanol containing 2 or 3% of concentrated hydrochloric acid. With 90% methanol containing 2% of concentrated hydrochloric acid the maximum degree of esterification of pectic acid was 86.1% in the reaction for 16 hr at 70°C, and was 76.2% in the reaction for 168 hr at room temperature. With 30% methanol containing 2% of concentrated hydrochloric acid the esterification was 16.8% in the reaction for 24 hr at 60°C. However, it was found that a fully esterified pectin could not be prepared by the present procedure. Low-methoxyl pectinic acids were esterified with the same procedure as that for pectic acid; the degree of esterification of pectinic acids increased by 35% in average in the reaction for 16 hr at 50°C as compared with the starting materials having the degree of esterification of 20 to 41%.
These results suggest the possibility for preparing pectinic acid having various degrees of esterification.