不同提取方法对黄秋葵果胶理化性质影响

Physiochemical Properties of Okra Pectin Extracted by Different Methods

分别采用微波辅助酸法、水浴硫酸法和纤维素酶法提取黄秋葵果实的果胶,研究不同提取方法对果胶提取率及其理化性质的影响,比较三种方法提取果胶的p H、酯化度、半乳糖醛酸、DPPH自由基清除率和热稳定性的差异。结果表明:三种方法对果胶提取率存在显著差异(p<0.05),纤维素酶法提取率最高,为29.57%,水浴硫酸法最低,为24.80%;与水浴硫酸法和微波辅助酸法相比,纤维素酶法提取的果胶p H最高,且具有显著性差异(p<0.05)。三种方法提取的果胶的酯化度均大于50%,说明黄秋葵果胶属于高甲氧基果胶,其中水浴硫酸法提取果胶的酯化度最高,有显著影响(p<0.05);三种方法测得的半乳糖醛酸含量不存在显著性差异(p<0.05);三种方法提取果胶的DPPH自由基清除率均随浓度的增加而增大,水浴硫酸法最高;黄秋葵果胶在热处理作用下黏度先迅速下降后缓慢趋于稳定。

Three different methods microwave method, water bath method and cellulase method are used to extract pectin from okra. The pH, ester value galacturonic acid content, the DPPH scavenging activity, and heat stability of the pectin extracted by three different methods were analyzed. The result showed that extraction rate of water bath extraction was significantly higher than the other two methods. The pH of pectin did not show much difference. The degree of esterification of the pectin was bigger than 50% regardless of the method being adopted, indicating that okra pectin was a kind of high methoxyl pectin. There was no significant difference on galacturonic acid content （p〈0.05）, the DPPH scavenging capacity of the pectin increases as with the pectin solution concentration, among which pectin extracted by water bath method had the highest value. The viscosity of okra pectin first decreased sharply and then remained stable.