Study On Vacuum Freeze Drying Technology Of Chestnut

The vacuum freeze-drying technique with good QianXi chestnut was systematically studied in this paper. Peeling method, mechanism and inhibition of browning, eutectic and co-melting temperature, pre-freezing temperature of chestnut were studied and determined during pre-processing process through experiments. Parameters of freezing-drying process: vacuum, condenser temperature, temperature and time of sublimation, temperature and time of desorption, were studied, and the optimal freeze-frying process of raw chestnut kernel was obtained. The main aspects and the results were represented as follows:1. The optimal peeling method of chestnut: The different peeling method had different effects on quality of freeze-drying chestnut kernel, and boiling in 100℃ water in 2 minutes to peel chestnut was optimal method among air-dry, drying, boiling water.2. Inhibition of browning of chestnut kernel: There was pertinence between the browning and the content in the processing of chestnut kernel. Different parts of kernel had different levels of tanning, 'team', surface and the inner part contented more. The more content of tanning, the more possibility of browning would take place. A lot of factors such as the water quality, temperature, time, pH value, affected the browning of chestnut in different degree. Different browning preventives could avoid the browning of chestnut in some extent. 0.01%tea-polyphenol+0.1%citric acid+0.1%EDTA+2% NaCl was optimal.3. Pretreatment: The gasproof membrane of the surface of chestnut kernel prevent vapor from coming out from the interior of chestnut kernel during sublimation...