The Effect Of EGCG On Greasiness Of Apple Fruit

Greasiness is pretty common during postharvest storage period which severely influences the fruit quality and brings down the sales of apple fruits.To the best of our knowledge that greasiness is associated with changes of cuticular waxes,so it is key to explore an inhibitor that could inhibit the synthesis of wax and retarding greasiness.Fatty acid synthase(FAS)is the key enzyme for wax synthesis,which could be inhibited by epigallocatechin-3-gallate(EGCG).In order to investigate the effect of EGCG on greasiness development during storage period,different apple cultivars are treated with EGCG in different concentration and stored at 25°C subsequently.The soluble solid content,titratable acidity,fruit firmness,ethylene production and respiration rate are measured to study the relation of EGCG and apple fruit quality.The content of fatty acids and esters in wax are measured to study the relation of EGCG and the accumulation of wax.The results showed that:1.The degree of greasiness of two apple cultivars increased during storage,but the greasy degree of control fruits increased rapidly than that of EGCG-treated fruit.Moreover the inhibitor effect of EGCG of 3.0 g·L-1 was better.2.The main waxes compounds in ‘Pink Lady’ fruit were fatty acids and esters,including: linoleic acid,oleic acid,lauric acid,tridecanoic acid,eicosenoic acid,palmitoleic acid,farnesol linoleate,farnesol oleate,butyl linoleate and propyl linoleate.The main waxes compounds in ‘Jonagold’ were linoleic acid,oleic acid,palmitic acid,stearic acid,behenic acid,palmitoleic acid,lauric acid,myristic acid,butyl linoleate,farnesol linoleate,amyl linoleate,butyl oleate,farnesol oleate and propyl linoleate.There had differences in waxes content and composition between the two apple cultivars.The content of waxes was lower at early storage and showed a positive correlation with time in the period of storage.The accumulation pattern of fatty acids and esters was in concert with the greasy level.However,the content of fatty acids and esters in EGCG-treated fruits were lower than that in control fruits,especially in medium-trem of the storage.3.The soluble solid content,tritratable acidity,fruit firmness,ethylene production and respiration rate in EGCG-treated fruits were not significant than that in control fruits.It indicated that EGCG had no influence on fruit quality.4.These results showed that EGCG had an influence on the synthesis of wax,instead of fruit quality.Besides,EGCG had no threat on human health.Therefore,EGCG could be used as an effective preservative in apple industry,which could improve the fruit quality by inhibiting greasiness of apple skins and increase the commercial value of apple fruit at the same time.