果胶酶酶解预处理对马铃薯泥干燥特性及生粉加工特性的影响

为提高马铃薯生粉的干燥效率,考察了果胶酶酶解预处理不同时间(60~180min)对马铃薯泥热风干燥特性及制备的酶解马铃薯生粉(pectinase-treated native potato flour,PNPF)理化性质和加工特性的影响。结果表明:果胶酶酶解处理降低了马铃薯泥果胶含量和初始含水量,提高了薯泥干燥速率,干燥时间缩短了6.32%~7.81%；果胶酶酶解预处理制备的生粉中果胶、灰分、蛋白质含量显著降低,直链淀粉、支链淀粉和总淀粉含量显著提高,淀粉相对结晶度和生粉碘蓝值降低；同时酶解预处理制备的生粉与未处理生粉相比,具有较高的溶解度和溶胀度,持油性显著降低,持水性提高了40.49%~49.58%,冻融析水率降低了26.23%~62.11%,其中酶解预处理180min制备的生粉(PNPF180)冻融稳定性提升幅度最大；糊化特性分析结果表明,PNPF峰值温度降低,峰值时间缩短,崩解值上升,最终黏度和回生值下降。果胶酶酶解预处理可改善马铃薯泥热风干燥特性,缩短干燥时间,同时显著改善马铃薯生粉基本理化性质及加工特性。

Effect of Pectinase Enzymolysis Pretreatment on Drying Characteristics of Raw Mashed Potato and Processing Properties of Native Potato Flour

To improve the drying efficiency of native potato flour, the effect of pectinase enzymolysis pretreatment with different time (60-80min) on hot air drying characteristics of raw mashed potato and physicochemical and processing properties of prepared pectinase-treated native potato flour (PNPF) were investigated. The results showed that the pectin content and initial water content of raw mashed potato were reduced after pectinase hydrolysis treatment , consequently improved the drying rate and caused greatly reduction of the drying time by up to 6.32%-7.81%. The contents of pectin, ash and protein in PNPF significantly decreased after pectinase treatment. Furthermore, amylose, amylopectin and total starch contents in PNPF increased significantly, and the relative crystallinity of starch and iodine blue value of PNPF decreased. At the same time, PNPF had higher solubility and swelling degree, and oil holding capacity was reduced significantly compared with non-treated flour. The water holding capacity was increased by 40.49%-49.58%. Moreover, the freeze-thaw water syneresis rate of PNPF decreased by 26.23%-62.11%, and the PNPF prepared by 180 min pectinase enzymolysis treatment exhibited the best freeze-thaw stability. The gelatinization characteristic analysis showed that peak temperature of PNPF decreased, the peak time shortened, the breakdown value increased, and the final viscosity and retrogradation decreased. In conclusion,pectinase enzymolysis pretreatment could improve hot air drying characteristics of raw mashed potato, shorten the drying time, and significantly improve the basic physicochemical and processing properties of the native potato flour.