Characterization of aroma compounds in the peel extract of Jabara (Citrus jabara Hort. ex Tanaka)

Abstract

Volatile compounds in the peel extract of Jabara (Citrus jabara Hort. ex Tanaka), a Japanese sour citrus, have been investigated using GC-FID, GC-MS and GC-olfactometry. The peel extract was obtained by solvent-assisted flavour evaporation after solvent extraction. The GC-FID and GC-MS analyses led to the identification of 49 compounds, including myrcene (46.8%), limonene (28.2%) and γ-terpinene (15.5%) as major constituents. Interestingly, the level of myrcene was much higher than that of limonene known as the main volatile constituent in citrus peel. This specific composition indicated that Jabara was a rare species among citrus fruits. Application of aroma extract dilution analysis revealed 22 odour-active compounds with the flavour dilution (FD) factor ranged from 8 to 16 384, and 19 of these compounds were identified. Myrcene, which showed the highest FD factor of 16 384, was regarded as the most character impact odorant in the Jabara peel extract. It should be noted that (3E,5Z)-1,3,5-undecatriene (FD = 512), (3E,5Z,8Z)-1,3,5,8-undecatetraene (FD = 256), 1,3,5,7-undecatetraene (unknown stereochemistry, FD = 256) and (6Z,8E)-6,8,10-undecatrien-3-one (FD = 16) were detected as potent odorants with green and fruity aroma, despite their trace levels in the extract. In addition to these, 7-methyl-1,6-octadien-3-one, having a metallic and mushroom-like odour, was identified as a further key contributor to the aroma of Jabara peel extract. This novel odorant has been reported for the first time as a volatile constituent in a natural product.

Volatile Compounds in Citrus Essential Oils: A Comprehensive Review

“…Sun et al (2014b) diluted the C. maxima EO in two steps: by 5,000-fold dilution in ethanol for analysis of the most abundant volatiles and 100-fold dilution for the minor volatiles. However, in other studies, the oil is not diluted (Mitiku et al, 2000; Song et al, 2000b; Choi et al, 2001; Minh Tu et al, 2002b, 2003b; Choi, 2005; Njoroge et al, 2005a,b, 2008; Sawamura et al, 2005; Akakabe et al, 2010; Cheong et al, 2011b; Omori et al, 2011). When volatile and semi-volatile compounds are extracted with an organic solvent, the samples are concentrated before direct injection using a rotary evaporator and further reduced under a stream of N 2 (Hamdan et al, 2010; Miyazato et al, 2012).…”

“…Other studies of Citrus peel composition use organic solvents such as pentane (Feger et al, 2001a; Miyazawa et al, 2010), pentane: ether (1:1) (Chisholm et al, 2003a,b), hexane (Inafuku-Teramoto et al, 2011; Miyazato et al, 2012, 2013), dichloromethane (Buettner et al, 2003; Craske et al, 2005; Cheong et al, 2011a; Omori et al, 2011; Cannon et al, 2015) or ethyl acetate (Jiang et al, 2011) to obtain different extracts. Also the organic system solvent n -pentane: diethyl ether (1:2) has been used to obtain the volatile organic compounds (VOCs) from Citrus flower (Alissandrakis et al, 2003).…”

“…ex Tanaka (kabosu) (Minh Tu et al, 2002b; Tomiyama et al, 2012), C. jabara Hort. ex Tanaka (Omori et al, 2011), C. hystrix D.C. (kaffir lime) (Jirapakkul et al, 2013), Citrus sp. (Kiyookadaidai) (Minh Tu et al, 2003a), Citrus hallabong ( C. unshiu Marcov × C. sinensis Osbeck) (Choi, 2003b), C. nobilis Lour.…”

Characterization of odour‐active compounds of sweet orange essential oils of different regions by gas chromatography‐mass spectrometry, gas chromatography‐olfactometry and their correlation with sensory attributes

“…studied the volatile extracts of pummelo peel by GC‐MS and sensory evaluation. Omori et al . used GC‐MS and GC‐O to investigate the volatile compounds in the peel extract of Jabara.…”

Variation Patterns of the Volatile Compounds in Flowers of Chinese Native Citrus Species and Their Taxonomic Implications

“…Citrus fruits can be consumed fresh or be processed into desserts, juices and jams and are good resources of vitamin C, folic acid, flavonoids, dietary fiber and many other health-promoting substances (Miller et al 2011). In the food industry, citrus processing produces an enormous amount of byproducts, such as pomace, which represents 50% of the raw fruits and is a good source of volatile compounds (Anwar et al 2008;Omori et al 2011). In addition, citrus essential oils, which are a mixture of volatile compounds consisting mainly of monoterpene hydrocarbons, have been widely used in food, pharmaceutical and cosmetic industries as flavoring agents, and as antibacterial, antifungal and antioxidant agents (Ferhat et al 2006).…”