金冠苹果及优系(SGP-1)果实品质与挥发性物质比较分析

Comparison of fruit quality and volatile compounds between Golden De-licious apple and the new strain originated from its occasional seedling(SGP-1)

【目的】对比分析金冠苹果及其变异优系(SGP-1)果实主要品质与挥发性物质等方面的差异,为品种选育与创新利用提供材料基础和理论依据。【方法】以金冠苹果及SGP-1为试材,利用常规方法测定果实主要外观和内在品质;采用GC-MS对果实挥发性物质进行定性、定量分析。【结果】(1)两材料主要品质指标差异达到显著水平,SGP-1的果肉硬度、糖酸比、色度值L和a较金冠分别提高了9.94%、80.91%、6.31%、27.14%,果锈指数和可滴定酸含量分别降低了80.0%和52.8%。(2)两材料中共鉴定出44种挥发性物质,其中SGP-1有38种,相对含量大于1.00%的挥发性物质有13种;金冠有34种,相对含量大于1.00%的挥发性物质有14种;主要由酯类、醇类、萜烯类等化合物组成,但不同品种的挥发性物质差异较大,SGP-1酯类物质相对含量高于金冠,醇类物质则低于金冠。(3)共有27种挥发性物质确定为两材料差异挥发物,SGP-1中的己酸甲酯、2-甲基丁酸丙酯、丁酸乙酯等24种化合物相对含量较高,具有较高贡献值,且显著(p<0.05)高于金冠;金冠中的6-甲基-5-庚烯-2-酮、2-乙基-1-己醇、丁酸丁酯等3种化合物相对含量较高,具有较高贡献值,且显著(p<0.05)高于SGP-1。【结论】SGP-1果实的果锈指数、含酸量及糖酸比较金冠有显著改善,且挥发性物质种类丰富,具有独特而浓郁的香味,综合性状优于金冠苹果。

【Objective】Golden Delicious is one of the main apple cultivar in the alpine plateau in South-west China.It is popular for high eating quality.However,its fruit surface is easily rusty.The fruits of new strain SGP-1 selected from occasional seedling of Golden Delicious have less rust,lower acidity and stronger aroma.The purpose of this study was to investigate the differences in fruit quality and vola-tile substances of Golden Delicious and its offspring SGP-1 in order to provide a theoretical basis for the possible use of the new strain.【Methods】The rust index,the peel color,single fruit weight,the fruit index,hardness,soluble solids,titratable acid,vitamin C,sugar and acid components of Golden Deli-cious and SGP-1 were detected by conventional methods.The volatiles of the fruits were analyzed quali-tatively and quantitatively by gas chromatography-mass spectrometry.【Results】(1)The fruit surface of SGP-1 was densely waxy,smooth and less rusted,the fruit spots was small and thin,besides,the sunny side was bright and red.The main quality indexes of the two materials had significant differences.Com-pared with Golden Delicious apple,the pulp firmness,sugar-acid ratio,color value L and a of SGP-1 fruits were respectively increased by 9.94%,80.91%,6.31%,27.14%,the rust index and titratable acid respectively decreased by 80.0%and 52.8%.(2)A total of 44 volatile substances were identified in the two materials,mainly composed of compounds such as esters,alcohols,and terpenes.SGP-1 had 38 vol-atile substances,including 25 kinds of esters,5 kinds of terpenes,3 kinds of alcohols,2 kinds of ethers,1 kind of aldehydes,1 kind of phenols,and 1 kind of aromatic hydrocarbons;the content of esters was 76.51%,the content of terpenes was 12.69%,and the content of alcohols was 7.04%;phenols were unique substances,accounting for only 0.19%.There were 13 kinds of volatile substances with relative content over 1.00%in the fruits of SGP-1.There were 34 volatile substances,including 20 kinds of es-ters,4 kinds of terpenes,4 kinds of alcohols,2 kinds of ethers,2 kinds of aldehydes,1 kind of ketones,and 1 kind of aromatic hydrocarbons in the fruits of Golden Delicious;the relative content of esters was 53.87%;followed by alcohols(20.21%)and terpenes(10.55%);ketones were unique substances,ac-counting for only 0.10%.There were 14 kinds of volatile substances with relative content over 1.00%in the fruits of Golden Delicious.The above showed that the components and contents of volatile substanc-es of the two materials were quite different,resulting in a unique and rich aroma of SGP-1 fruits.(3)The Variable Importance of Projection(VIP)was used to analyze the contribution of each volatile sub-stance in the PLS-DA model to the difference between the two materials.A total of 27 volatile com-pounds were identified as differential volatiles.The 24 compounds such as Hexanoic acid,the methyl ester,Butanoic acid,2-methyl-,propyl ester,Butanoic acid,ethyl ester,Acetic acid,butyl ester,Butano-ic acid,propyl ester,Butanoic acid,2-methyl-,2-methylbutyl ester,1-Butanol,2-methyl-,acetate,Octa-noic acid,ethyl ester,Hexanoic acid,ethyl ester,2-Butanoic acid,2-methyl-,ethyl ester,Hexanoic acid,butyl ester,Estragole,2-Butenoic acid,2-methyl-,4-methylpentyl ester,(E)-,Butanoic acid,2-methyl-,heptyl ester,Hexanoic acid,pentyl ester,Hexanoic acid,2-methylbutyl ester,Butanoic acid,2-methyl-,pentyl ester,Octanoic acid,hexyl ester,Eugenol,Butanoic acid,2-methyl-,hexyl ester,Butyl 2-methyl-butanoate,Alpha-Patchoulene,Acetic acid,pentyl ester and Hexanoic acid,and hexyl ester in the fruits of SGP-1 were higher than those of Golden Delicious(p<0.05)and had higher contribution values.The contents of 5-Hepten-2-one,6-methyl-,1-Hexanol,2-ethyl-and Butanoic acid,butyl ester in the fruits of Golden Delicious were higher,and their contribution values were higher than those of SGP-1(p<0.05).【Conclusion】Compared with Golden Delicious apple,the fruit rust index,acid content and sugar-acid content of SGP-1 fruits were significantly improved,and the aroma components were rich in the fruits of SGP-1,and the comprehensive characters of SGP-1were better than Golden Delicious.The molecular mechanism of less rust,low acidity and rich aroma in SGP-1 apple need to explore in the near future.