Effect Of Cultivar, Maturity And Infection On Aroma Component Of Citrus Fruit

Citrus is one of the most important commodity fruit all over the world, the aroma component has increasingly become a research focus ponit for citrus. In this paper, we choose key factors for the citrus edible ability and not for processing, the cultivar, maturity and storage of citrus fruit were study. Aroma components and taste quality of five commercial navel oranges were analysed by using solid phase microextraction and gas chromatography-mass spectrometry, and principal component analysis were adopted to investigate their aroma components; The changes of quality characteristic and aroma component during fruit development(October to December) of Citrus Sinensic Osbeck. cv. Jincheng 447# were anlysis; Health Valencia oranges were inoculated pathogens which induceed occurrence of common diseases(green mold and blue mold), and there are wound and none wound two controls, the volatile components of different treatment were dectected by GC/MS for analyzing, we report volatiles differences among the treatments through characteristic volatiles, volatiles compontents and multivariate analysis of volatiles. Through the studies above, conclusions were made as follows:1. Principal Component Analysis of five commercial navel oranges arom components65 aroma components belongs to monoterpenes, Sesquiterpenes, aldehydes, ketones, alcohols and esters were identified in five commercial navel oranges, those aroma components are 15 alcohols,11 aldehydes,5 ketones,7 esters,9 monoterpenes,15 sesquuiterpenes and 3 others.38 components were identified in newhell navel orange, 24 components were identified in fengjie navel orange,35 components were identified in gannan navel oranges,31 components were identified in changhong navel oranges, 35 components were identified in beibei navel oranges.65 aroma components from 5 commercial navel oranges were used to principal component analysis, the results showed that:four principal component count for 90% above of the total variation ratio, the first principal component and the secend component were represented monoterpenes and oxide derivatives of terpenoids. Navel oranges have flavor characteristic due to the variance of aroma components and taste quality, and principal components analysis of navel orange's aroma components can be a potential method for navel orange aroma quality.2. Quality Characteristic and Aroma Components Analysis of Citrus Sinensic Osbeck. Cv. Jincheng 447# During Growth and Development PeriodsA total of 76 aroma components belongs to various chemical classes such as aldehydes, alcohols, esters and terpenes were identified during fruit growth and development periods, and there had a larger different among development stages in those chemical classes both number of category and relative content. During fruit development, alcohols substances were declined, relative content appears a trend first decline and increased later; Aldehydes were species appear first increased and then decreased trend; Esters relative content shows ascendant trend; Monoterpenes relative content were declined slowly; Sesquiterpene relative content were increase quickly. During fruit development, total soluble solid content, VC and reducing sugar content indexes shows a ascendant trend, but titration acid content after the first decline rise. Through arome components principal component analysis, five growth stages could be think as three stages, in various stages of growth to control fruit aroma components in those stages, could develop Citrus Sinensic Osbeck. cv. Jincheng 447# reasonablely.3. Effect of fungal diseases on aroma components of Valencia OrangeVolatile organic compounds collected from the headspace of Valencia Orange inoculated with Penicillium digitatum (green mould), Penicillium italicum (blue mould), initial citrus, mock (as the first control) and non-wounded-non-inoculated mango (as the second control) were analyzed using GC/MS to investigate the feasibility of volatile metabolite as a indicator to diagnosis diseases of citrus in stores. Results showed that a total of 104 metabolites were identified based on mass spectral match using NIST library. Several of these were specific to adisease/inoculation or when common to all treatments, they varied in their abundances. There are 14 metabolites were specific to Penicillium digitatum-inoculated citrus while 9 metabolites were detected only in Penicillium italicum-inoculated citrus.2,3,3-trimethyl-octane,2,4-diphenyl-methyl-1-pentene, Ethyl acetate and Methyl butyrate were detected only in infected citrus. The study has shown for the first time that it is possible to detect and differentiate between bule mould and green mould diseases of Valencia Orange based on their volatile production patterns using GC/MS. The methods developed here have the potential applications to citrus industry to detect and diagnose diseases of citrus fruits, at different stages of the disease progress, after validation under commercial conditions.