真空冷冻干燥猕猴桃粉工艺的研究

Study on the Process of Vacuum Freeze-drying Kiwifruit Powder

针对猕猴桃常规干燥保存过程中不易成粉且化学添加剂过多等问题,本文比较了热风干燥、喷雾干燥、冷冻干燥3种干燥方式下猕猴桃粉的品质,并研究了冷冻干燥法制备猕猴桃粉过程中,预冻方式、浆体比例、助干剂种类、猕猴桃新鲜度等因素对猕猴桃粉品质的影响。结果表明:相比热风和喷雾干燥,冷冻干燥法制备的猕猴桃粉综合品质较好、速溶性好、产率较高;采用冻干法制备猕猴桃粉的较优工艺为选取九成熟(盛花后约175天)的猕猴桃去皮打浆,以体积比(猕猴桃浆:酸奶)1∶1添加酸奶,铺料厚度4mm,经-20℃预冻后,在真空环境下干燥10h。

The effects of hot air drying, spray drying and freeze drying on the quality of kiwifruit powder are compared in this paper, and the effects of pre-freezing method, slurry ratio, type of drying aid and freshness of kiwifruit on the quality of kiwifruit powder prepared by freeze drying are studied. The results show that the freeze-dried kiwifruit powder has better overall quality,instant capacity and higher yield compared to hot air drying and spray drying. The preferred process for the preparation of kiwifruit powder by freeze-drying is to select nine-ripe kiwifruits(approximately 175days after flowering), peel, pulp, and add yogurt in a volume ratio of 1 ∶1 with kiwi pulp, then spread the slurry at a thickness of 4mm, pre-freeze at-20℃ and then dry it under vacuum for 10h.