Studies On Aroma Components And Correlation Analysis Of Peach Fruit In Protected Culture

Based on the protected cultivation practices of peach trees, the experiments had been carried out in the horticultural demonstration garden of Shandong Agricultural University from the year 2005 to 2006 ,peach cultivars for Chunjie(Prunus persica cv.chunjie.),Chunxue(Prunus persica cv.chunxue.), Wuyueyangguang nectarine(Prunus persica var. nectarina Maxim. cv. Wuyueyangguang),and Shuguang (Prunus persica var. nectarine Maxim. cv. Shuguang) were used as experimental materials. The major research contents were just as following: the effect of protected cultivation on fruit quality and aroma components; differences of content and sorts of fruit aroma components during fruit development in protected culture; differences of main aroma components in different cultivars of peaches in protected; relevant analysis between inclusions and aroma sorts of peach fruit. The main results were as follows:1,Compared with cultivation in the open, studies indicated that the fruit growth and formation of quality were nearly the same even though the fruit quality decreased. Single fruit weight changed slowly in early period while increased quickly in the flowing period of fruit development ; the content of titratable acid increased firstly then decreased ;the content of soluble sugar kept increasing before 58days after full blossom; then decreased slowly before78 days and last began to increase when the fruit approached mature; Vc and amino acid gradually decreased as fruit development; the content of protein first increased then decreased before 50 days after flower full blossom ,after then the content decreased sharply and reached the lowest level in fruit mature stage.2,Protected cultivation had a markedly effect on fruit aroma components and content. In protected cultivation, the content of such fruity and floral components as esters and lactones etc. in Chunjie and Chunxue peaches decreased, while such components as alcohols and aldehydes etc. with the green grass odor increased; and the sorts of aroma components less than that of protected culture; content and sorts of such characteristic aroma components of peaches as E,E-2,4-Hexadienal,Benzaldehyde,Z-3-Hexenal, Caprolactone,Gamma-decalactone,Delta-decalactone etc decreased. But it had little effect on Wuyueyangguang nectarine of which some aroma components were more in both content and sorts than without protected. The content of Aspartate was the highest in all the amino acids of the cultivars both in and out of protected. The content of every amino acid in protected was more than that of out, except Glutamate of Chunjie peach and Cysteine of Wuyueyangguang nectarine.3,The aroma constituents present in Chunjie peach in protected culture during seven periods of fruit development were studied. The result indicated that a total of 42,41,44,36,48,60,52 compounds were identified in the different development stages after full blossom, the main constituents were alcohols, esters, aldehydes, ketones, acids, alkanes and terpenes. During early development stage, the main constituents of fruit were Benzaldehyde,E-2-Hexenal etc. While in the ripe stage, aldehydes increased, and some characteristic of aroma components such as lactones were detected, The content of C6 aldehydes and alcohols decreased as the fruit grew ripe. 2-Hexenal,linalool,caprolactone,acetic acid,hexyl ester,ethyl acetate,γ-dodecalactone,δ-decalactone were detected and increased rapidly when the fruit grew ripe.4,The aroma constituents present in peach fruit of the four cultivars in fruit ripe stage in protected culture were studied. The fruits were sampled by solid phase extraction. A total of 51,52,51,57 kinds of aroma components were identified in Wuyueyangguang, Shuguang nectarines and Chunjie, Chunxue peaches. Alcohol, aldehydes, esters, lactones, ketones, alkanes and terpenes were main components in peaches and nectarines. They were major contributors to peach and nectarines aroma, but their contents were different in the four cultivars. Wuyueyangguang nectarine had more characteristic aroma components of ripe peach than others such as Benzaldehyde and lactones etc. And it was perceived more full-bodied aroma of peach. In addition, the four kinds of peaches and nectarines had their own difference aroma components.5,Research of relative relationship between such nutrition indexes as soluble sugar,titratable acid,Vc,protein,amino acid,monosaccharide ( including sucrose,glucose,fructose),organic acid (including malic acid, citric acid) etc. and aroma components of Chunjie peach indicated that the content of alcohols,esters,lactones in fruit all had significantly positive correlation with fruit development, while aldehydes had significantly negative correlation with fruit development; protein and sucrose both both had significant correlation with many aroma components. So they had great effect on synthesis of aroma components. Correlation analysis between nutrition indexes and fruit characteristic aroma components showed that hexanal had respectively significantly positive correlation with glucose and negative correlation with citric acid, benzaldehyde had high positive correlation with Vc and amino acid ,and it had negative correlation with soluble sugar and citric acid. 18 sorts of amino acids were detected in peach fruit, and the content of Aspartate was the highest in all the amino acids, the varying trend of every amino acid content also varied as the fruit development, and it also demonstrated that there was a correlation between the variation in content of amino acid and the aroma components, of which the amino acid such as glycine,valine,phenylalanine,arginine,tyrosine,methionine and isoleucine etc. had significant correlation with fruit characteristic aroma components, these amino acids were mostly precursors of ester synthesis, and they all had great effect on fruit flavour.