以狐臭柴叶为原料、柠檬酸为酸解液提取果胶,采用单因素实验、正交实验对酸浓度、提取温度、料液比和提取时间等条件进行探索,并以响应面实验设计方法进行工艺优化。结果表明:酸浓度和料液比是影响果胶酸解的主要因子;一定范围内,酸浓度与果胶粗产率(Y1)呈线性正相关,料液比与果胶粗产率(Y1)呈线性负相关,二者与粗果胶半乳糖醛酸含量(Y2)的关系符合二元二次多项式方程模型,但随着酸浓度的增加和料液比的降低,半乳糖醛酸含量有下降趋势;半乳糖醛酸提取率(果胶有效提取率Y3)的拟合效果是一个平均值模型,即Y3=8.86%。在提取温度、提取时间分别为90℃和120 min,响应面的优化条件为酸浓度3.91%、料液比1∶44.09时,果胶粗产率、半乳糖醛酸含量和果胶有效提取率分别为36.72%、32.09%和11.78%。
Citric acid was used to extract the pectin of Premna puberula leaves. Through single factor experiments and orthogonal design, the extraction process was studied involving four factors (acid concentration, extracting temperature, solute/solvent ratio and extracting time). The response surface methodology (RSM) was used to optimize the process of pectin extraction. The results show that the acid concentration and solute/solvent ratio were two key factors affecting pectin extraction ratio;within a certain range, acid concentration and pectin crude yield (Y1) was a positive linear correlation, solute/solvent ratio and pectin crude yield (Y1) was a negative linear correlation, the relationship both acid concentration and solute/solvent with galacturonic acid (GalA) content (Y2) of the crude pectin accorded with the model of binary quadratic polynomial equation;and GalA content had a downward trend with increase of acid concentration and decrease of solid-liquid ratio;the fitting effect of GalA extraction ratio (pectin effective extraction ratio Y3) was an average model, i.e. Y3=8.86%;the pectin crude yield, GalA content and pectin effective extraction ratio were respectively 36.72%, 32.09%and 11.78%at 90℃(extracting temperature), 120 min (extracting time), acid concentration 3.91%and solute/solvent ratio 1︰44.09.