Effects Of Pre-Treatments On Postharvest Physiological And Aromatic Quality Of Postharvest Mango Fruit

In this paper, effects of pre-bagging treatment on physiological characteristic and aromatic quality of postharvest mango fruit and pre-harvest oxalic acid treatment on physiological response and aromatic quality of in ’zill’ and ’keitt’ mango fruit were investigated respectively. Mango fruits were treated with pre-harvest bagging and oxalic acid for one time and twice respectively and then stored at constant temperature of 25 ℃.Changes in quality and anti-oxidant index combined with aromatic quality of mango fruit were measured during storage. The major results of this research were as follows:The ’zill’ fruit appearance quality was effectively improved, increases of soluble solid content (SSC) and decreases of titratable acidity (TA) were alleviated, and disease index was decreased, Ca,Mg,Na,K,Fe,Cu,Mn and Zn mineral elements were increased with the treatment of pre-bagging.The results showed that 30 kinds of components were detected at different stages, and the aromatic compounds and their relative contents varied among these stages. Terpenes such as 3-carene, limonen, cyclohexene, 1-methyl-4-(1-methylethylidene),and caryophyllene were the main aromatic compounds in mango fruit during the ripening process. In the pre-bagging fruit, the relative contents of terpenes increased by 17.40% and 5.91% at the mature green and full-ripening stages, and the relative contents of aldehydes also increased by 210.28% and 19.69% at the half-ripening and full-ripening stages, respectively, whereas the types and relative contents of esters and lactones decreased by 5 numbers or 80.09% at full-ripening stage, as compared to the control fruit.The decreases in fruit firmness were alleviated, titratable acidity (TA) and soluble sugar (SS) increased, disease index and decay incidence decreased with pre-harvest oxalic acid for one time and twice.Besides,the activity of anti-oxidant enzymes including peroxidase(POD), superoxide dismutase(SOD)and polyphenol oxidase (PPO) increased,however, LOX activity, MDA production and ethylene production decreased, and H2O2 and O2·-decreased in mango fruit treated with the pre-harvest oxalic acid. The contents of Ca,Na,Fe and Mn elements increased at the full-ripening stage by pre-harvest oxalic acid for one time. The results showed that 24 kinds of components were detected at the different stages,and the relative content of terpenes accounted for 72.46%～98.88% of the total volatile components,the main aromatic compounds were 3-Carene;lR-.alpha.-Pinene;1H-Cycloprop[e]azulene,1a,2,3,4,4a,5,6,7b-octahydro-1,1,4 ,7-tetramethyl-,[1aR-(1a.alpha.4.alpha.,4a.beta.,7b.alpha.)]-;Caryophyllene;Cyclohexen e,l-methyl-4-(1-methylethylidene)-.Terpenes in the aromatic compounds of mango fruit with pre-harvest oxalic acid treatment remained relative high content, and did not change the characteristic compounds.