响应面法优化苹果渣中果胶的柠檬酸提取工艺

Optimization of Pectin Extraction from Apple Pomace with Citric Acid by Response Surface Methodology

确定柠檬酸提取苹果渣中果胶的最佳工艺条件,并评价其乳化特性。以苹果渣为原料,采用柠檬酸溶液提取乙醇沉淀的方法提取果胶,通过单因素试验研究料液比、提取温度、提取时间、pH对果胶得率的影响。在此基础上,采用响应面法优化苹果渣果胶的提取工艺条件;并以乳化性及乳化稳定性为考察指标,评价果胶的乳化特性。苹果渣果胶的最佳提取条件:提取温度95℃、提取时间95 min、pH 1.5、料液比1∶25(g/mL)、提取两次,在此条件下,果胶得率为14.45±0.20(%),其半乳糖醛酸含量为73.31±5.14(%),酯化度为68.03±7.11(%),乳化性为38.51±6.13(%),乳化稳定性在30 d内保持在80%以上。利用响应面法可确定柠檬酸提取苹果渣中果胶的最佳工艺条件,且实验结果还表明柠檬酸提取的苹果果胶具有良好的乳化性和乳化稳定性。

The paper aims to explore the optimal extraction conditions of pectin from apple pomace with citric acid and evaluate the emulsifying properties.Pectin was extracted from apple pomace,using citric acid as the extracting solvent and followed by ethanol precipitation.In the single-factor tests,the effects of material-liquid ratio,extraction temperature,extraction time,and pH of solution on the yield of pectin were investigated.Based on the single-factor tests,response surface methodology was used to optimize the extraction conditions of pectin from apple pomace.Meanwhile,the emulsifying properties of pectin was assessed by emulsifying activity and emulsifying stablility.The optimum extraction of pectin from apple pomace was obtained as follows:extraction temperature 95 ℃,extraction time 95 min,pH 1.5,material-liquid ratio 1∶25(g/mL),repeated twice.Under these conditions,the yield of pectin was 14.45±0.20(%),the content of galacturonic acid was 73.31±5.14(%),and the degree of esterification was 68.03±7.11(%).Emulsifying activity of apple pectin was 38.51 ± 6.13%,and the emulsion stability was over 80% within 30 days.Response surface methodology is applicable for the optimal extraction conditions of pectin from apple pomace with citric acid.The obtained pectin has good emulsifying activity and emulsifying stability.