| Twelve apple cultivars including high acid content varieties, Judelin, Judaine, Avrolles, Granny Smith, White winter pearmain, Ralls, and fresh-eating varieties including Jin Hong, Hong Yu, Hua guan, Hong Wang Jiang, Golden Delicious, were selected to investigate the quality characteristics. The soluble solid content, total acid, soluble solid-acid ratio, vitamin C, hardness, apple pulp color value and aroma components were detected, apple varieties quality characteristics were comprehensive evaluated. This article also studied the quality characteristics and differences between two main regions, Luochuan and Xingcheng counties where Qian Qiu apple fruits grown, and aromatic components in different tissue parts such as peel, pulp and core of Granny Smith apple. The aroma components were collected using head-space solid phase microextraction (HS-SPME), analyzed by gas chromatographmass spectrophoto-meter (GC-MS). Different apple cultivars aroma components'quantitative was conducted by internal standard method. Aromatic components in different tissue parts' quantitative were conducted by peak areas normalization method. Apple cultivars aroma components'quantitative were conducted by internal standard method and classified by principle component analysis (PCA). This study also built up new apple aroma components analysis method and provided basic statistics for different apple cultivars aroma components fingerprint's setting up.(1)A significant difference in aromatic components was observed in peel, pulp and core of Granny Smith apple fruit. The aromatic components were rich in peel and 55 kinds of aromatic components were identified in this tissue. The highest content of C6 aldehydes was observed in this tissue part, which exhibited a relative content of 39.515%. A total of 23 esters with relative content of 14.240% were identified and esters were the most predominant group of compounds in Granny Smith apple's peel, which mainly provided background ester aromatic components. Hexyl acetate, cyclobutanol, (E)-hexa-1,4-diene, (3E,5E)-hepta-1,3,5-triene,3,6-diethyl-3,6-dimethyl- cyclohexa-1,4-diene exhibited higher content amony the whole apple peel aromatic components. Meanwhile,18 compounds were detected in apple pulp. Totally 4 kinds of alcohols exhibited a relative content of 31.391% and 2-methylbutan-l-o1 was up to 94.814%. Propyl propionate and hexyl formate had higher relative content and were characteristic aromatic components of the pulp. Moreover,30 components including 2 kinds of C6 aldehydes were identified in the core. Totally 4 kinds of alcohols with a relative content of 42.455% were also identified and 2-methylbutan-1-ol and hexan-1-ol were up to 96.639%. Among these aromatic components from different tissue parts of Granny Smith apple, propyl propionate and hexyl formate were mainly distributed in apple pulp; 2-methylbutan-l-ol was mainly generated in the core and the pulp; hexan-1-ol was rich in the core and the peel; alpha-farnesene was mainly located in the peel and the core; hexanal and (E)-hex-2-onal as its high content in the peel, the pulp and the core, were the characteristic aromatic components of Granny Smith apple fruit.(2)The total acids content, soluble solid content of Qian Qiu apple grown in Xingcheng county were higher than grown in Luochuan county while its soluble solid-acid ratio was lower than Qian Qiu apple grown in Luochuan county, which means Qian Qiu apple grown in Luochuan county had sweater taste. Ascorbic acid content, fruit firmness and apple pulp's value of the Qian Qiu apple fruit exhibited unobvious difference. Characteristic aromas of Qian Qiu apple grown in Luochuan county were ethyl butanoate, butyl propanoate, hexyl acetate, hexyl hexanoate, pentyl acetate, (E)-2-hexenal, (E)-heptenal, and 1-octen-3-one. Characteristic aromas of Qian Qiu apple grown in Xingcheng county were butyl propanoate, hexyl acetate, hexyl hexanoate, pentyl acetate, hexyl 2-methylbutanoate, and (E)-2-hexenal. Qian Qiu apple aroma components belonged to esters aroma type. The typical aroma compounds of Qian Qiu apple were ethyl butanoate, butyl acetate, hexyl acetate, pentyl acetate and hexyl hexanoate. The main Qian Qiu apple aroma differences between the two regions were their background ester compound kinds and main flavor compounds. Qian Qiu apple grown in Luochuan country have higher aroma compound content and was rich in aroma kinds.(3)Characteristic aromas of six cultivars of apple, Judelin, Judaine, Avrolles, Granny Smith, White winter pearmain and Rails were determined. Principle component analysis showed that Hexyl acetate, Hexyl-2-methylbutyrate, Butyl acetate, Isoamyl acetate, Hexyl hexanoate, and Hexanal were the main discriminating variables for classification of apple aroma. The main aroma components of the 6 apple cultivars were all aldehydes. The first type was "aldehydes strong green flavor", to which aroma of Avrolles apple belonged, as its high aroma content concentration about 2-4 times as much as that of other types. The second type was "aldehyde soft green flavor", to which apple fruit aroma of Granny Smith, Ralls, Judeline, and Judaine belonged, as their simple aroma components and low content. The third type was "green banana flavor" to which aroma constitutes of White Winter Pearmain apple belonged, as its high content of banana esters components. Judeline, and Judaine apple fruit had suitable solid-acid ratio, higher color value, and aldehyde green odor, so they were the ideal materials to produce good taste and pleasant appearance of no-from-concentrate juice. Avrolles and Granny Smith apple fruit had higher VC content and total acid content, so their juice was more suitable to blend with other low acid apple juice.(4)Characteristic aromas of the five fresh-eating apple cultivars, Jin Hong, Hong Yu, Hua Guan, Hong Wang Jiang, Golden delicious were determined. Principle component analysis showed that ethyl butyrate, ethyl hexanoate, and 2-methyl-hexyl acetate were the main discriminating variables for classification of apple aroma. The first type was ethyl hexanoate ester sweet flavor, to which aroma of Golden delicious apple belonged, as its high aroma content concentration of ethyl hexanoate whose relative odour contribution was 84.841%. The second type was 2-methyl-hexyl acetate ester sweet flavor, to which aroma of Hong Wang Jiang apple belonged, as its high aroma content concentration of 2-methyl-hexyl acetate whose relative odour contribution was 67.941%. The third type was ethyl hexanoate ester sweet flavor, to which aroma of Hua guan, Hong Yu, and Jin Hong apple belonged, as its high aroma content concentration of ethyl hexanoate whose relative odour contribution was more than 60%. Golden delicious apple had higher soluble solid-acid ratio, and VC content, so it tasted sweeter than the other cultivars. Hong Yu apple fruit had lower soluble solid-acid ratio, so it tasted sourer than the other cultivars. All the other apple cultivars' fruit had suitable soluble solid-acid ratio and good taste.
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