基于均匀设计和主成分分析的甘薯薯片油炸工艺优化

摘要

为优化甘薯薯片油炸工艺,采用单因素和均匀设计相结合进行试验,对均匀设计试验数据进行多元回归分析.单因素试验表明:切片厚度、预干燥阶段和油炸阶段对含油量、L*值和b*值有较大影响;均匀设计逐步回归分析表明:油炸时间对含油量影响显著(P=0.011),食盐水质量分数对含水量影响显著(P=0.022),油炸温度和油炸时间对L*值影响极显著(P=0.001),预干燥时间和油炸时间对b*值影响显著,食盐水浸泡时间、食盐水质量分数、预干燥温度、预干燥时间和切片厚度对脆度的影响符合二次多项式回归模型(P=0.001);指标主成分分析表明:提取2个主成分能解释87.4％的指标信息,达到指标降维目的;岭回归分析建立了综合得分回归模型,相关系数R为0.997,能很好地拟合产品的综合得分;偏最小二乘法回归分析预测最佳综合评分工艺参数为切片厚度2mm、热烫时间1 min、质量分数1％食盐水浸泡20 min、预干燥温度60℃、预干燥时间70 min、油炸温度150℃、油炸时间1 min,验证综合评分为0.89,综合评分高于均匀设计试验组最高值0.86.优化工艺所得产品具有含油量低、颜色和脆度俱佳等特点,相关模型具有良好的预测能力.%In this work,we optimized the frying process for sweet potato chips using combination of one-factor-at-a-time method and uniform design through multiple regression analysis of the uniform design experimental data.The results of the one-factor-at-a-time experiments showed slice thickness,pre-drying and frying to be the factors with a great influences on the oil content,L* and b*.Uniform design and stepwise regression analysis indicated that frying time significantly influenced the oil content (P =0.011),saline concentration influenced significantly water content (P =0.022),frying temperature and frying time affected very significantly L* (P =0.001),drying time and frying time significantly influenced b*,and saline immersion time,saline concentration,pre-drying temperature and time and slice thickness affected brittleness,which was fitted to a quadratic polynomial regression model (P =0.001).Principal component analysis (PCA) showed that the two principal components extracted accounted for 87.4％ of the total variation,thus achieving dimensional reduction.Through ridge regression analysis,we established a regression model for comprehensive score with a correlation coefficient R of 0.997,suggesting a good degree of fitting.Partial least squares regression analysis predicted that the best process parameters were as follows:slice thickness,2 mm;blanching time,1 main;saline immersion time,20 min;saline concentration,1％;pre-drying temperature,60 ℃;pre-drying time,70 rmin;frying temperature,150 ℃;and frying time,1 min.The validation experiment gave a comprehensive score of 0.89,which was higher than the highest score (0.86) from uniform design.The product obtained under the optimized conditions had a low oil content,and accepted color and brittleness,and the proposed model had good prediction ability.