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以商品柑橘高酯果胶为原料制取低酯果胶。重点探讨了低温碱法脱酯时间对果胶质量和得率的影响并比较了异丙醇、甲醇沉淀果胶的效果。以果胶的半乳糖醛酸含量、酯化度(DE值)、黏度、得率等为分析对象。结果表明,低温下(4℃)碱法脱酯可将影响果胶品质的β-消去反应控制在较小程度,所得产品黏度能最大程度得到保持。柑橘高酯果胶碱法脱酯的最佳工艺条件为pH9.0,控制温度在4℃,处理30min,沉淀果胶用异丙醇,该条件所得果胶半乳糖醛酸含量为86.57%,DE值为47.98%,得率为81.5%,指标达到低酯果胶产品的标准。
The low-ester pectin is made from the commodity citrus high-ester pectin as raw material. The effects of low temperature alkali de-esterification time on the quality and yield of pectin were discussed, and the effects of isopropyl alcohol and methanol precipitation pectin were compared. Pectin galacturonic acid content, esterification degree (DE value), viscosity, yield as the analysis object. The results showed that the β-elimination reaction which affected the quality of pectin could be controlled to a lesser extent by alkali de-esterification at low temperature (4 ℃), and the viscosity of the obtained product could be kept to the maximum extent. The optimal conditions of citrus high ester pectin de-esterification were pH9.0, control temperature at 4 ℃, treatment time 30min, precipitation of pectin with isopropanol. The content of pectin galacturonic acid was 86.57% DE value of 47.98%, yield was 81.5%, the index reached the standard of low-ester pectin products.