Authors

Abstract

Sanbai Melon, as a national geographical indication product and a characteristic agricultural product of Shanxi Province, is named for its white skin, white flesh and white seeds. It is mainly produced in Wanrong County, Yuncheng City, Shanxi Province. The three-white melon is not only rich in various vitamins and amino acids, but also has significant medicinal value. It can clear heat and detoxify, clear the lungs and moisten the intestines, reduce internal heat and protect the liver. However, the market availability of Sanbai melon is limited to the period from July to December each year. Due to the excessively long gap in its availability and the inability to meet people's daily consumption needs, it is imperative to turn Sanbai melon into freeze-dried powder. By studying the correlation between dielectric characteristic parameters and the moisture content and dielectric characteristics of Sanbai Melon, and combining single-factor test analysis, response surface analysis and other methods, the optimal freeze-drying process parameters of Sanbai Melon are analyzed and studied. Based on the results of the previous pre-test, the vacuum degrees were set at 35-40pa, 40-45pa, and 45-50pa, the heating plate temperatures at 60℃, 70℃, and 80℃, and the material thicknesses at 3mm, 6mm, and 9mm. The optimal freeze-drying process parameters of Sanbai Melon were studied through a three-factor and three-level experiment. Taking time as the target variable and moisture content, dielectric constant and dielectric loss factor as dependent variables, the optimal vacuum degree obtained by response surface analysis is 40-45pa, the heating plate temperature is 73℃, the material thickness is 7mm, and the freeze-drying time is 6 hours. Under these parameters, the moisture content of Sanbai Melon is 2.9% and the dielectric constant is 2.195. The dielectric loss factor is 1.525.

Abstract in Chinese

三白瓜作为全国地理标志产品、山西省特色农产品，以皮白、瓤白、籽白而得名，主要产于山西省运城市万荣县。三白瓜不仅富含多种维生素和氨基酸，而且具有显著的药用价值，能清热解毒、清肺润肠、败火护肝，但是，三白瓜的上市时间只在每年7月份到12月份，针对其空档期太大、不能满足人们的日常食用需求等问题,将三白瓜做成冻干片势在必行。 通过研究介电特性参数与三白瓜片含水率之间的相关关系，结合单因素试验分析、响应面分析等方法，对三白瓜片的最佳冻干工艺参数进行分析和研究。根据前期预试验结果，设定真空度为35~40pa、40~45pa、45~50pa，加热板温度为60℃、70℃、80℃，物料厚度为3mm、6mm、9mm。通过三因子三水平试验，研究三白瓜片最佳冻干工艺参数。以时间作为目标变量，以含水率、介电常数、介电损耗因子作为因变量，用响应面分析法得到最优真空度为40~45pa，加热板温度为73℃，物料厚度为7mm，冻干时间6h，在此参数下三白瓜片的含水率为2.9%，介电常数为2.195，介电损耗因子为1.525。