| Fragrant pear fruits is a famous,excellent and characteristic fruit in Xinjiang.It has a good quality and is loved by consumers.It is marketed throughout the country and was exported to more than 20 countries and regions,accounting for 50%of Xinjiang's annual fruit storage.The first fruit storage in Xinjiang is fragrant pear.Epidermal wax of the pear fruits directly or indirectly regulates the post harvested physiological and biochemical processes,storage of the fruit.The change of volatile substances affects the commercial value of the fruit.Therefore,research on wax metabolism and volatile substances in the pear fruit was performed.To elucidate the changes of differential metabolites,metabolic pathways,volatile and antioxidant enzyme activities,and provide a theoretical basis of the storage and preservation technology of pears.Fragrant pear was invoked as a test material to study the effects of 1-MCP treatment for waxy metabolism and volatile matter production of pear fruits.The results that:1.A total of 73 volatile substances were identified with the pear fruits of the cold storage(-1.5??0?,relative humidity 90%?95%),alcohols(14 types),aldehydes(13 types),acids(6 types),esters(11 types),ketones(10 types),alkanes(8 types).1-MCP treatment might reduce the types of volatile substances of fragrant pear fruits and esters,ketones,alkenes,alkanes,and volatile substances are inhibited in fruits during the early storage,the middle of storage.Aldehydes are promoted in fruits of the middle of storage,the end of storage.Volatile substances of pear fruits maintained by 1-MCP treatment for cold storage.Delay the decline in fruit Hue-angle,firmness and Vc content,and prolong the fruit quality of cold storage.2.A total of 100 volatile substances were detected in fruit of 1-MCP treated group and control group during the shelf life(22??25?,relative humidity 80%?85%).Compared with shelf life of 210+3 d,the volatile substances of 1.0 and 5.0 ?L/L 1-MCP treatments increased 16,15 and 14 kinds of volatile substances,respectively,were added at 210+6 d;respectively,and 19,14 and 7 types were added at 210+9 d.The volatile substances that are suppressed during the shelf life are alcohols.The 1-MCP treatment could delay the decline in fruit Hue-angle,weight loss rate,inhibit the increase of wax content,and prolong the shelf life quality.3.During storage at room temperature(22??25?,relative humidity 80%?85%),1-MCP treatment could maintain high catalase(CAT),peroxidase(POD)adn superoxide dismutase(SOD)activity of pear fruits compared with control;slow down the decrease of fruits Hue-angle and firmness;delayed the increase in malondialdehyde(MDA)content,cell membrane permeability,greasiness level and wax content,inhibited the production rate of superoxide anion(O2-·)and the content of hydrogen peroxide(H2O2),and delayed the appearance of respiratory peak.1-MCP treatment can maintained the activity of antioxidant enzymes in fruits,and delayed the process of fruits senescence.4.During storage at room temperature(22??25?,relative humidity 80%?85%),a total of 156,153,138 differential metabolites were screened for the group 20 CK vs.CS,group 20 M vs.CS,group 25 M vs.25 CK.Seven metabolic pathways were identified by the differential metabolites Hexadecanal,1-Hexadecanol,alpha-Tocophero,2-Phenylacetamide,Propionic acid.Phenylalanine metabolism,Propanoate metabolism,Ubiquinone and other terpenoid-quinone biosynthesis are highly correlated metabolic pathways in the group 20 CK vs.CS.Ubiquinone and other terpenoid-quinone biosynthesis is highly relevant metabolic pathways to the group 20 M vs.CS.Phenylalanine metabolism is a highly correlated metabolic pathway to the group 25 M vs.25 CK. |
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