The Volatile Constituents in the Peel and Pulp of a Green Thai Mango, Khieo Sawoei Cultivar(Mangifera indica L.).

Abstract

The essential oil in the peel and pulp of a popular green Thai mango, Khieo Sawoei cultivar (Mangifera indica L.) has been characterized by means of the odor thresholds. ␥-Terpinene, (E)-␤-ocimene, (E)-2-hexenal, hexanal, and (Z)-3-hexen-1-ol were the major components. These major components differed from those of African mangoes, Florida mangoes, Indian mangoes and yellow Thai mangoes. The volatile oils from the pulp and the peel showed a high similarity of the volatile components in both sites. Odor unit values (U o ) of volatile components in both parts let us find out the aroma potent components in the Khieo Sawoei mango. Thus, nine compounds: hexanal (U o ‫)981؍‬ and (E)-2-hexenal (U o ‫)231؍‬ in the pulp showed higher U o values (more than 1), while sixteen compounds: 2,4-decadienal ( Keywords: Mangifera indica L., Thai mango, Khieo Sawoei cultivar, peel oils, pulp oils, odor spectrum value, odor unit A number of volatile components from several kinds of mango fruits have been identified in past decades (Schreier & Idstein 1984;MacLeod & Snyder 1988b;Shibamoto & Tang, 1990). New techniques such as headspace analysis (Malundo et al., 1997;Vodovotz et al., 1993) and measurement of bound aroma compounds (e.g. glycosides; Adedeji et al., 1992) have been applied for the isolation and characterization of volatiles. In these various varieties, there is considerable variation in volatile composition and aroma quality. However, few studies concerning the volatiles in Thai mangoes have appeared in the literature. Recently, antioxidant compounds in mango peel fibres were reported to have beneficial effects on health in high-dietary-fibre diets (Larrauri et al., 1997). Gholap and Bandyopadhyay (1977) studied on the volatiles in the latex of green raw mango. Utilization of mango peels for industrial purpose (Rashad et al., 1990) must be encouraged more than before. Therefore, we demonstrated the possibility of utilization of the peel oils to improve the aroma quality of processed Thai mangoes.In Thailand, green mangoes are consumed in significant quantities as well as the yellow mangoes at the mature stage. Keaw species is the major greenish cultivar used for processing; Khieo Sawoei cultivar is a high quality cultivar for matured green mangoes in Thai markets. We have not found any papers reporting studies on the volatile compositions and aroma profiles of green mangoes. This paper deals with the identification and characterization of volatile components in a green Thai mango, Khieo Sawoei mango using odor unit values and odor spectrum values of the volatile components in the peel and the pulp. Materials and MethodsMaterials The Khieo Sawoei mangoes used in this study were obtained from a local market in Bangkok, Thailand in November 1996 and May 1997. This fruit can be harvested all year long in Thailand. The fresh fruits were frozen quickly at Ϫ20˚C and then transferred to Japan, where they were peeled and sliced. Finally, the fruit pulp was removed from the stone. The peel and the pulp were kept in a freezing room ...

Trace Volatile Components in Essential Oil of Citrus sudachi by Means of Modified Solvent Extraction Method

“…One micro-liter of sudachi oil was introduced into the GC. The quantities of compounds identified were calculated based on the gas chromatographic area percentage, the oil weight and total peel weight, and then expressed as ppm (Tamura et al, 2001).…”

“…Odor thresholds of 1,8-cineole, linalool, hexanal, and dodecanal were approximately 1-9 ppb. Diisopropyl disulfide, 2,6- Tamura et al, 2001; c) Padrayuttawat et al, 1997;d) Blank & Grosh, 1991;e) Tamura et al, 1999. L, OISϽ5%.…”

“…The odor threshold of the individual authentic compounds was determined by a two-out-of-five test as mentioned in previous papers Tamura et al, 1999), but some of the values were cited from the literatures (Blank & Grosh, 1991;Padrayuttawat et al, 1997;Tamura et al, 1999;Tamura et al, 2001). Odor unit value (U o ) of the individual volatile compounds was calculated by dividing the concentration of each compound by its odor threshold (Guadagni et al, 1966;Rothe & Thomas, 1963).…”

“…Odor impact spectra (OIS) were calculated according to the concept of odor unit values (Tamura et al, 2001) and normalized U o by an approximate Stevens' law exponent as 0.5 (Stevens, 1958). OIS are expressed as follows, : perceived odor intensity of individual compound.…”

“…However, it may be very hard to evaluate the aroma intensity of some volatile compounds, which have nearly the same retention time. A recent study introduced the concept of odor impact spectrum (OIS) from odor unit values (Tamura et al, 2001) instead of charm analysis (OngPeter & Acree, 1998) to visualize aromagrams of odor-active compounds. This avoids the obscure evaluation of the contribution among volatile compounds having close retention time in GC/O analysis (Tamura et al, 2001).…”