干燥方法对水蜜桃微观结构变化的影响

Effects of Drying Methods on Microstructure of Juicy Peach

为了描述不同干燥方法下水蜜桃微观结构的变化规律,以水蜜桃为物料,运用石蜡切片制备、显微观测、图像处理等技术获得了热风干燥(HAD),真空干燥(VD),冷冻干燥(FD),热风真空联合干燥(HA-VD)及冷冻热风联合干燥(F-HAD)过程中不同水分比下水蜜桃切片的显微图像和细胞微观结构参数分布曲线。分析了不同干燥方法对微观结构参数(细胞截面积、截面周长、圆度、壁面粗糙度及孔隙率)的影响,通过多项式拟合建立了水分比与微观结构参数的拟合方程。结果表明水蜜桃微观结构参数发生变化的阶段一般是在HAD的前半程(水分比1~0.5)以及VD和FD的后半程(水分比0.5以下)。干燥过程中细胞截面积均值的变化趋势为:FD<HAD<VD<HA-VD<F-HAD,细胞截面周长均值变大的幅度依次为:HAD<HA-VD<VD<F-HAD<FD,细胞圆度均值变小的程度依次为:HAD<FD<F-HAD<HA-VD<VD,细胞壁面粗糙度均值增大幅度依次为:F-HAD<VD<FD<HA-VD<HAD,孔隙率增大的程度依次为:FD<F-HAD<HAD<HA-VD<VD。这表明与单一干燥方法相比,对应的组合干燥能够显著抑制微观结构参数的变化。研究结果为探究不同干燥方式下水蜜桃微观结构参数随水分比的变化规律和建立水蜜桃在干燥过程中的数学模型提供重要参考。

To describe the changes of juicy peach microstructure under different drying methods,microstructure images and cell parameter distribution curves of juicy peach under different moisture ratios were obtained by using paraffin section,micro-imaging and image processing technologies,after treated by five drying methods(i.e.hot-air drying(HAD),vacuum drying(VD),freeze drying(FD),hot-air and vacuum combined drying(HA-VD),freeze and hot-air combined drying(F-HAD)).The effect of drying methods on microstructure parameters(i.e.,cell area,cell perimeter,cell roundness,cell wall surface roughness and porosity)were analyzed via cell parameters distribution curves.Fitting equations were built by polynomial fitting to describe the correlation between cell parameters and moisture ratios.The results showed that microstructural parameters of juicy peach primarily changed in the first half process(moisture ratio>0.5)of hot air drying and second half process(moisture ratio<0.5)of vacuum and freeze drying.The changing trend of cell area was FD<HAD<VD<HA-VD<F-HAD.Cell perimeters increasing was HAD<HA-VD<VD<F-HAD<FD.Cell roundness decreasing was HAD<FD<F-HAD<HA-VD<VD.Cell wall surface roughness increasing was F-HAD<VD<FD<HA-VD<HAD.Degree of porosity increase was FD<F-HAD<HAD<HA-VD<VD.Compared with single drying methods,the change of microstructure parameters was significantly inhibited by using corresponding combination drying methods.The results provided an important reference for exploring variation of microstructure parameters and establishing mathematical model of juicy peach with moisture ratios under different drying methods.