低温真空油炸粉葛片工艺优化及其品质分析

Optimization and Quality Comparison of Low Temperature Vacuum Fried Pueraria thomsonii Crisp Chips

为实现粉葛的全质化利用,本文采用低温真空油炸工艺制备粉葛片。在单因素实验基础上通过正交试验优化了低温真空油炸粉葛片的制备工艺。结果表明,最优工艺为粉葛片厚度2 mm,油炸温度105℃,油炸时间35 min,漂烫时间3 min。在最优条件下粉葛片脆性值为989.35 g,脂肪含量为22.95%。此外,还比较了不同工艺制备的粉葛片品质。漂烫、冷冻处理后低温真空油炸粉葛片的脂肪含量较低,脆性值较高,而通过漂烫冷冻常规油炸所得粉葛片含水量(1.71%)和脆性值(597.54 g)最低,脂肪含量达62.24%。未漂烫粉葛片常规油炸后脂肪含量显著高于低温真空油炸所得粉葛片(P<0.05),而脆性值无显著性差异(P>0.05)。油炸粉葛片香气物质以氮氧化合物、硫化物和有机硫化物为主,但是不同油炸所得粉葛片香味有明显差异。经油炸后粉葛片表面蜂窝状结构消失,通过漂烫冷冻低温真空油炸的粉葛片表面有少许孔洞,而在未冷冻的葛根片表面形成一层凝胶层。

To fully utilize the Pueraria thomsonii,low temperature vacuum frying technology was applied to prepare crisp chips from Pueraria thomsonii.On the basis of single factor tests,the optimal process was determined by orthogonal experimental design.The optimum conditions were listed as follows:Thickness of chips 2 mm,frying temperature 105℃,frying time 35 min,and blanching time 3 min.The crispness value and fat content of Pueraria thomsonii crisp chips under the optimum conditions was 989.35 g and 22.95%,respectively.In addition,the quality of Pueraria thomsonii crisp chips from different processes were compared.The Pueraria thomsonii crisp chips produced under the low temperature vacuum fried process and treated by bleaching and/or freezing showed lower fat content and higher crispness values.The crisp chips produced under the conventional frying process treated by bleaching and freezing technology presented the lowest water content(1.71%)and crispness value(597.54 g),but the fat content was as high as 62.24%.The fat content of Pueraria thomsonii crisp chips produced by conventional frying without bleaching pretreatment was significantly higher than that after low-temperature vacuum frying process(P<0.05),but there was no significant difference in crispness value(P>0.05).After frying,the main aroma substances of Pueraria thomsonii crisp chips were nitroxide,sulfide and organic sulfide.However,there were obvious differences in the aroma for the different frying process.After frying,the honeycomb structure on the chips disappeared.There were a few holes on the surface of Pueraria thomsonii crisp chips produced by low temperature vacuum frying process.However,there was gel layer on the Pueraria thomsonii crisp chips without freezing treatments.