| The fruit aroma is one of the important intrinsic fruit qualities,which largely determines people’s buying tendency.Chinese dwarf cherry fruits have an unique aroma,which varies greatly among different germplasms,and the fruit aroma is affected by the developmental stages and environmental changes.In this study,the fruit aroma components of 87 Chinese dwarf cherry germplasms at their mature stage were determined the fruit aroma components of 5 germplasms such as ’Jinou 1’ at different developmental stages were then determined.Finally,the effects of different treatments on the fruit aroma components were evaluated.The results of this study could provide a theoretical basis for the breeding and utilization of Chinese dwarf cherry with different aroma types.The findings are as follows:1.In 87 Chinese dwarf cherry germplasms,the aroma content changed from 0.8395-298.5145mg/Kg,with an average of 53.8526 mg/Kg and a coefficient of variation of 112.67 %.The total aroma content were clustered into four categories: low,(0.8428-47.471 mg/Kg,including 54 germplasms,represented by ’Jinou 1’ and ’Nongda 5’);medium(56.9214-127.7024 mg/Kg,including 24 germplasms,represented by ’Nongda 6’ and ’99-02’);medium-high(163.519-221.0404 mg/Kg,including 3 germplasms,represented by ’03-25’);high(251.5813-295.7652mg/Kg,including 3 germplasms,represented by ‘3-54’.2.A total of 643 aroma components were detected in 87 germplasms,and the number of aroma components ranged from 47 to 111,with an average of 90.6897 and a coefficient of variation of10.11 %.These 643 components can be classified into 12 categories such as esters and alcohols.The six types of ingredients such as esters,alcohols,aldehydes,ketones,lactones,and other oxides are commonly present in all germplasms.According to the principal component analysis results,the principal components of Chinese dwarf cherry aroma were mainly esters and alcohols.The Ester content ranged from 0.2273 to 180.9581 mg/Kg.There are 32 germplasms of which the ester content account for more than 50 % of total aromatic substances,while 52 germplasms are in the range of 10-50 % and 3 germplasms were less than 10 %.The average proportion of esters was51.47%,and there are 7 aroma compounds’ content more than 1% and 2 aroma compounds’ content more than 10%.The alcohol content ranged from 0.3462-103.1004 mg/Kg.There are 6germplasms of which the alcohol content account for more than 50 % of total aromatic substances,while 81 germplasms are in the range of 10-50 %.The average proportion of alcohol was 27.42%,and there are 5 aroma compounds’ content more than 1%.Two aroma compounds are commonly presented in all 87 germplasms: Linalool and à,4-dimethyl-3-Cyclohexene-1-acetaldehyde;while there are four aroma compounds commonly presented in 86 germplasms: Ethyl2-(5-methyl-5-vinyltetrahydro furan-2-yl)propan-2-yl carbonate,hexyl acetate,α-terpineol and trans-2-hexenal.Therefore these 7 compounds could be used as a characteristic aroma of Chinese dwarf cherry.3.The fruit aroma components of varieties ’Jinou 1’,’Nongda 5’,’Nongda 6’,’Nongda 7’ and’99-02’ at their different developmental stages were also determined.The highest total amount of aroma were observed at the ripening stage for the first four germplasms,while the total aroma content of ’99-02’ decreased slightly at the ripening stage.There was no significant difference in aroma composition between the ripening stage and the mature stage.The content of esters and alcohols as a whole showed an upward trend,while the content of aldehydes showed a downward trend.The number aromatic compounds of varieties ’99-02’ and ’Nongda 7’ were higher than other germplasms at every developmental stages.There are 6 aromatic compounds presented in all fruit developmental stages: Linalool,Geraniol,Etyl2-(5-methyl-5-vinyltyrahydrofuran-2-yl)propan-2-yl carbonate,α-terpineol,and trans-2-hexenal.4.Under the greenhouse conditions,the total aroma content of the three varieties ’Jinou 1’,’Nongda 6’ and ’Nongda 7’ decreased by 3.22 %,47.76 % and 30.69 %,and the contents of ester and alcohol were also decreased.Under shade conditions,the total aroma content of the two varieties ’Nongda 6’ and ’Nongda 7’ decreased by 69.54 % and 85.90 % respectively.Similar results were found when they were treated with 50 % shade(the total aroma content decreased by 73.08 %and 7.35 % respectively).5.Treated the ’Jinou 1’ and ’Nong Da 7’ fruits with 6 months’ low temperature at-40 °C,the total aroma content significantly dropped(92.58 % and 90.09 %,respectively).The esters content decreased by 86.36 % and 93.55 %,respectively.Alcohols content also decreased by 91.86 % and94.25 %.The total aromas decreased by 96.48 % and 92.64 % when treated with 18 months’ low temperature at-40 °C,while esters decreased by 93.64 % and 92.27 %,and alcohols dropped by94.51 % and 90.09 %,respectively.6.In the process of fruit juice production,the 33.41% aroma compounds was lost,and the loss rate after enzymolysis reached 75.11 %.Therefore the fruit smashing and enzymolysis were the two main steps causing the loss of fruit juice aroma.The total aroma content of fruit juice was 73.58 %lower than that of the fresh fruit.The juice aroma compounds are mainly alcohols.A total of 21 aroma components were detected in fruit wine,and the aroma content was 193.14 % higher than that of fresh fruit,mainly esters.However,only 3 compounds were the same as the fresh fruit aroma.The aroma content in processed products(calcium tablets)was 75.81 % lower than that of fresh fruits,and there were only 5 aroma components different from the fresh fruit aroma.Without same chemical compounds exist between calcium tablets and fresh fruit,but there are some same chemical compounds with juice and wine.7.The effect of different cultivation on the aroma composition of ‘Jinou 1’ was not significant.The content of each component was affected to some extent,but no significant difference. |
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