Effects Of Methyl Salicylate On Storage Quality And Aroma Quality Of Apricot Fruit During Cold Storage

Apricot fruit is popular among consumers because of its color,fragrance and taste.Commercially,‘low temperature storage+cold chain transportation’is often used to store and transport apricot fruits,but after low temperature storage and transportation,apricot fruits will appear aroma loss,which seriously affects the aroma quality of apricot fruits.Methyl salicylate（MeSA）has been shown to enhance the chilling resistance of fruits and reduce chilling injury symptoms during cold storage.There have been no reports of MeSA affecting the aroma quality of horticultural products after harvest.Therefore,‘Jintaiyang’and‘Pingdingxiang’apricot were used as experimental materials in this study.The effects of postharvest MeSA fumigation on the physiological quality and aroma quality of apricot fruits during cryogenic storage were investigated as follows:（1）Headspace solid phase microextraction combined with gas phase mass spectrometry was used to analyze aroma components of apricot fruits.Six main aroma components were detected in two varieties of apricot fruits,which were alcohols,aldehydes,ketones,terpenoids,esters and lactones.Among them,44 aromatic compounds were identified in‘Jintaiyang’apricot,including 5 alcohols,13 aldehydes,2 esters,5 lactones,8 ketones and 11 terpenoids.A total of 43 aromatic compounds were identified in‘Pingdingxiang’apricot,including 5 alcohols,8 aldehydes,5 esters,6 lactones,6 ketones and 13 terpenoids.The effects of low temperature stress on physiological quality of apricot fruits were studied by low temperature storage experiment at 4℃.The results showed that storage at 4℃inhibited the decrease of fruit hardness,the increase of soluble solid（SSC）,and the ethylene release rate and respiration rate of apricot fruits.Storage at low temperature,the contents of alcohols and aldehydes in apricot fruits were maintained,which inhibited the decline trend of‘green aroma’,and the contents of esters and lactones in apricot fruits were reduced,which significantly inhibited the rise of‘fruit aroma’.（2）The effects of MeSA(0.1 mmol L^-1,1.0 mmol L^-1and 2.0 mmol L^-1)fumigation on storage quality and shelf quality of apricot fruits were investigated.The results showed that MeSA treatment could effectively delay the changes of hardness,SSC,ethylene production rate and respiration rate of apricot fruits during low temperature storage,maintain the low temperature storage quality of apricot fruits,and improve the shelf quality of apricot fruits to a certain extent.In addition,MeSA treatment accelerated the downward trend of‘green aroma’fragrances and promoted the upward trend of‘fruit aroma’fragrances.The 1.0 mmol L^-1mesa treatment could not only delay the ethylene jump peak and the softening of fruits,but also better maintain the aroma quality of apricot fruits after harvest.（3）The effects of MeSA on the metabolism of aroma substances in apricot fruits during low temperature storage were studied.The results showed that 1.0 mmol L^-1MeSA treatment promoted the biosynthesis of esters and lactones aroma substances in apricot fruits.MeSA promoted the biosynthesis of volatile aldehydes by promoting the activity of hydrogen peroxide lyase（HPL）in apricot fruits,and inhibited the content of volatile alcohols by inhibiting the activity of alcohol dehydrogenase（ADH）in apricot fruits.MeSA promoted the synthesis of esters by enhancing the activity of ethanolacyltransferase（AAT）,and increased the content of lactone aroma substances by enhancing the activity of acyl-co A oxidase（ACX）,A key enzyme in theβ-oxidation pathway.In conclusion,MeSA fumigation technology can improve the low temperature storage quality and shelf quality of apricot fruits,and enhance the contents of esters and lactones by enhancing the activities of AAT and ACX enzymes,so as to improve the aroma quality of apricot fruits.