The Component Characteristics Of Volatile Substances From Different Apples At Germplasm Level

As the champion of fruit production,the apple which has a long cultivation history are planted in temperate regions around the world.The production and consumption of apple in China are the highest in the world.With the constant improvement of the people’s quality requirement for apple,its production is transformed from quantity to quality,and the quality characteristic is one of the basic factors of transformation.One of the challenges faced by improving of apple quality is not enough for understanding of quality of the existing apple germplasm resources,especially lack of understanding of special quality of the apple germplasm resources.Among them,the composition and content of apple volatile substances can objectively reflect its flavor characteristics,and is one of the reasons for consumer choose and buy.However,the existing researches involved only a few apple varieties.The headspace solid phase microextraction combined with GC-MS(HS-SPME-GC-MS)was used to extract and analyze the composition and content of volatile substances from the 138 apple germplasms,so as to reveal their quality characteristics and differences.The results showed that:(1)A total of 108 volatile compounds were detected from the 138 apple germplasms,and was classified to 9 classes,and the most of them was belong to esters,alcohols and aldehydes.There were 12 typical volatile substances,such as butyl acetate,2-methyl butyl acetate,hexyl acetate,2-hexen-1-ol acetate,hexyl butyrate,1-hexanol,5-ethyl,3-methyl heptyl 1-ene-4-alcohol,2-ethyl-1-hexanol,hexanal,2-hexene aldehyde,limonene and 2-pentyl furan.(2)The content of volatile substance in apple was generally not high.Almost half of them was less than 2% of the total.The 28 volatile substances greater than 2% were widespread in most apple germplasm resources,and the 29 ones more than 2% were only existed in one or several germplasm.(3)Through cluster analysis,the 138 apple germplasms can be classified into four categories: the cultivated varieties form Chinese,American and Japanese(I),the cultivated varieties form Canadian and French(II),the wild varieties(III),and the cultivated varieties form England(IV).The results showed that the cultivated varieties from Chinese,American,and wild varieties contained the richest volatile compounds.The total contents of the volatile compounds in American cultivated varieties varied hugely,while those in French cultivated varieties were nearly the equal.The aldehyde content of the wild species(III)were generally higher than the other categories;the category II had a higher content of alcohol;the ester content was higher in category IV.However,the category I did not show any special content of volatile compounds.In genaral,the study of volatile characteristics of 138 apple germplasm resources would provide the scientific basis for parental selection and quality breeding of high quality apple.