Study On The Character Isitic Of Polysacchari De-based Material To Preserve And Its Influence On Litch I Bio-heat Transfer

The characteristic of polysaccharide-based material and its influence on bio-heat's produce, variety and deliver of litchi had been studied. The relationship between storage effect of the litchi and its bio-heat transfer control by the coatings of different material stored in normal temperature had been investigated.The results show that, the less material's molecular weight, and the more concentration and the long stored days are, the high crystallization degree is. The water transfer properties include water vapor and water drop permeability, hygroscopicity and moisture retention of material. The water transmitting increased with high temperature. The hygroscopicity and moisture retention of material are better in high humidity; the result of heat transfer indicated that the rate of heat transfer get rapidly with the decreasing of acetyl substitution degree and glass transition temperature of material. With theincreasing of water transporting, and the decreasing of hygroscopicity and moisture retention of material the rate of heat transfer get better. Since the bio-heat transfer was produced by respiration over the storage period, it increased with respiration, which was associated with increased temperature. When the litchi was coated with polysaccharide-based material, it can keep fruit nutritive quality better and maintain polyphenol oxidase (PPO ) activity for long time, that is good effect obviously.With a serial experimental data, the author showed that litchi's evaporation is the main bio-heat transmitting modus. The result has reference to the studies on bio-heat transfer of fruit and vegetable.