基于灰色关联分析法研究不同干燥方式对芜菁脆片的影响

通过比较真空冷冻干燥（freeze drying，FD）、变温压差膨化干燥（explosion puffing drying，EPD）、红外干燥（infrared drying，ID）、热风干燥（hot air drying，AD）4 种不同干燥方式对芜菁脆片物理性质、营养成分、微观结构等的影响，寻找最优的芜菁脆片干燥方式。使用理化分析技术测定芜菁脆片营养成分含量；色差仪、质构仪等测定物理特性；扫描电子显微镜观察微观结构；评分法进行感官评价；灰色关联分析与变异系数分析结合进行综合评价。结果表明：4 种不同干燥方式处理后的芜菁脆片的物理特性和营养成分含量均有显著变化，FD和EPD对营养成分的保留更为完整。扫描电子显微镜观察结果显示FD可使芜菁脆片形成疏松多孔蜂窝状结构，EPD可使芜菁脆片产生轻微蜂窝状效果，同时使结构更为紧密，使口感酥脆。干燥方式综合评价结果为：FD＞EPD＞ID＞AD。但FD设备及加工过程花费较高，生产周期较长。综合考虑脆片的物理特性、营养成分、微观结构、感官评价以及生产周期，可得出EPD为芜菁脆片的最适加工方式。

Effects of Different Drying Methods on Turnip Chips as Evaluated Based on Grey Relational Analysis

In order to find the best drying method for production of turnip chips, the effects of four different drying methods of freeze drying (FD), hot air drying (AD), infrared drying (ID), and explosion puffing drying (EPD) on the physical properties, nutrient composition and microstructure of turnip chips were compared. The nutritional components were determined by chemical analysis, the physical properties were evaluated by a colorimeter and a texture analyzer, and the microstructure was observed by scanning electron microscopy (SEM). Also sensory evaluation was carried out. Furthermore, a comprehensive evaluation was performed using grey correlation analysis based on the coefficient of variation. The results showed that the physical properties and nutrient contents of turnip chips were significantly changed after each drying process. FD and EPD preserved more nutrients. SEM showed that FD chips had a porous honeycomb-like structure; EPD chips also exhibited a more compact honeycomb-like structure and tasted crispy. The comprehensive evaluation revealed that the drying methods were in the following decreasing order: FD > EPD > ID > AD. However, the cost of an FD device and the drying process was higher and the drying period was longer. Taken together, EPD was selected as the optimum processing method for turnip chips.