Effects Of Cultivar,Ripening Stages And Storage Methods On Volatile Components Of Lemon

Not only is lemon one kind of citrus fruits with highly nutritional values, but also the aroma is an important flavor quality, and the study of volatiles of lemon may contribute to the applications of lemon aroma in the daily life, breeding, cultivation and the other aspects. In this paper, we studied volatiles of lemon from three perspectives: cultivar,ripening stages and storage methods, which were extracted from lemon spring flowering fruit peel of Yunnan province. This research included the analysis of volatiles of lemon peel with six cultivars, the determination of physical and chemical properties of lemon fruit and volatiles of lemon peel from May to October, the investigation of the influences of storage in room temperature(25 ℃) and cold temperature(4℃) on volatiles of lemon peel. The main conclusions were made as follows:1. With the annlysis of volatiles from peel of six lemon cultivars, Sorrento, FSO2,d’Amalfi, Carelelo, Ruili Eureka and Anyue Eureka had 74, 69, 75, 72, 72, 73 kinds of volatiles, respectively, and the total number of volatiles was 81. Sorrento had the higherst total relative content(24999.00μg/g), however, Anyue Eureka had the lowest amount(11951.16μg/g). The percentage of oxygenated monoterpene compound had an obvious difference among these cultivars.Moreover, the percentages of oxygenated monoterpene compounds in d’Amalfi, Ruili Eureka and Anyue Eureka were higher than the other cultivars. Though the percentage of volatiles in Ruili Eureka and Anyue Eureka were quite similar, their relative contents of volatiles had an obvious difference.2. Through the determination of physical and chemical properties of lemon spring flowering fruits, the fruit weight, cross and longitudinal diameters, juice percentage were increased gradually, and the fruit shape index changed slightly. By the contrast, the pericarpe decreased in June and September, and titratable acids and total soluble solids went down in July. 43, 68, 73, 72, 60, 61 kinds of the total volatiles were identified in lemon peel from six periods. The relative content of total volatiles from lemon peel in May was the higherst(18467.16μg/g), while October showed the lowest amount(80092.12μg/g). The percentage of monoterpene hydrocarbons generally declined during ripening, but the percentage of oxygenated monoterpenes went up. Both of the percentage and relative content of d-limonene in May reached the peak, while β-myrcene, α-terpineol,neral, geranial, citronellal, decanal, which contributing to the special flavour of lemon,peaked their percentage and relative content in mature stage, from Augest to October.3. The numbers of volatiles detected in lemon peel after 0d, 30 d, 60 d and 75 d under room temperature(25℃) storage were 72, 58, 63 and 60, respecrtively, while that ofunder cold storage(4℃) were 72, 57, 60 and 58, seperately. The percentage of moneterpene hydrocarbons, saturated hydrocarbons with high carbon chain, acids and coumarins descended after both room temperature storage and cold storage, while oxygenated monoterpenes and sesquiterpene hydrocarbons increased, and oxygenated sesquiterpenes had little change during the storage. Furthermore, although the percentage of geranyl acetate, neryl acetate, nonanal and decanal before the storage were more than that of after the storage, d-limonene, bergaten, lineleic acid, linolenic acid and stearic acid,ect. were decreased.