Study On Molecular Mechanism Of Pericarp Discoloration And Effects Of Algae Oligosaccharide In Fresh-keeping Of Litchi

Litchi is one of the least storable fruits. Its pericarp is easy to turn brown, whichseverely decreases the commercial value of litchi. The postharvest discoloration oflitchi pericarp have a close relation with phenolic compounds. Algae oligosaccharidesis a preservative with application and development prospect. This paper used Wuyelitchi as raw materials and studied, molecular mechanism of pericarp discolorationand effects of algae oligosaccharide in fresh-keeping of Litchi. The main results areas follows:1,Experimental results showed that the pericarp discoloration of Wuye litchi isrelative with the change of anthocyanins,some flavanols and flavonols in pericarp atdifferent stages of storage.2,During storage, anthocyanin content and flavanols contents of litchi pericarpassume the certain linear relationship. The discoloration speed of litchi pericarptreated with cold preservative is slower than hot preservative, and degradation speedevery organic compositions in pericarp is also slower. The high temperature promotethe degradation of phenol compound of flavanone in pericarp, which showed that thecolor change of rind is a apparent change phenomenon which is caused by the changeof environmental factors promoting the degradation of various pigments sorestraining the synthesization of anthocyanin. It is the results that diversifiedsubstances and the environment through a complexing action. The change of color hasa complex internal adjustment mechanism.3,The results in the orthogonal test showed that the best storage conditions were:120ppm algae oligosaccharide, soaking for2min and storage at3℃, under which, thecommodity rate of Wuye Litchi was93%. After28days' storage.4,Taking commodity rate, browning index, total soluble solids, titratable acid,vitamin C, membrane permeability, respiration rate, and PPO activity as index tostudy the effect of algae oligosaccharide on the fresh-keeping effects of Wuye Litchiat room temperature. The results showed that the commodity rate of Wuye Litchi treated by120ppm algae oligosaccharide was86%with low browning index (1.54)after8days' storage at room temperature.