Stuides On Vacuum Cooling Impact And Its Effect On The Storage Properties Of Fruits And Vegetables

Precooling methods are the effective ways to weaken respiration heat and remove field heat after harvest in order to keep the quality of product and prolong its shelf life. Vacuum cooling is generally acknowledged for its most efficient cooling speed and effective cooling result. But when doing research on vacuum cooling, there is disadvandage in the traditional way of monitoring the change of temperature during the process of vacuum cooling, which may lead the quality loss of product in the end. In this paper, Infrared Thermography System is used to monitor the change of temperature, esapecially the phenomenon of supercooling for mushroom, then the research of supercooling on the quality of mushroom during storage is proceed. Main results of the research as follows:1) three typical vegetables (tomato, mushroom, greeengrocery)was choosed , Infrared Thermography System was used to monitor the surface temperatures of them during vacuum cooling at 300 Pa. The results showed that the changes of surface temperatures were significantly different among vegetables which have different surface characters, mushroom had the best cooling efficiency, followed by greengrocery, then tomato. Supercooling on the whole surface of mushroom was found during the process.2) The same phenomenon of Supercooling for mushroom was also found when the cooling pressure were 200 Pa, 300 Pa ,400 Pa and 500 Pa. Comparing weight change, moisture content, soluble solids content, respiration rate, electrolyte leakage and water activity of mushroom treated by different cooling pressure during storage, the result showed that when the cooling pressure is 400 Pa, the quality can be kept as mush as possibile.3) In the assistant of L*a*b* Color System and TPA mode, the color changes and mechanical properties of mushroom treated by different cooling pressure during storage was studied, it can be found that when the cooling pressure were 400 Pa and 500 Pa, Supercooling of mushroom surface does not affect the color and mechanical properties on the whole.4) The result of sensory analysis confirmed that when cooling pressure was 400 Pa, mushroom kept sensory quality during storage.