Variation Of Volatile Compounds Research Articles

Characterization of Flavor Compounds Released During Grinding of Roasted Robusta Coffee Beans

The characteristic volatile compounds released during the grinding of roasted coffee beans are as attractive for coffee-flavored products as the aroma of fresh-brewed coffee itself. In this study, the volatile compounds released during the grinding of various roasted robusta coffee beans (originating in Vietnam and Indonesia ; roasting degree L26, L23, and L18) were collected by exposing a solid-phase microextraction (SPME) fiber to nitrogen gas discharged from a glass vessel in which the electronic coffee grinder was enclosed. Identification and characterization of the volatile compounds were achieved using gas chromatography/mass spectrometry (GC/MS) and GC/olfactometry (GC/O), and by applying principal component analysis (PCA) to the GC/O results. The variation in volatile compounds released during grinding, based on origin, roasting degree and species, is described and compared with the results of a previous study on the compounds released during grinding of roasted arabica coffees.

Variation in volatile compounds from tansy (Tanacetum vulgare L.) related to genetic and morphological differences of genotypes.

Air-dried flower heads of 20 Finnish tansy genotypes were extracted with petroleum ether and analyzed using GC-MS. A total of 55 volatile compounds were detected, and 53 were identified. Of the tansy genotypes studied, 15 were well defined and five were mixed chemotypes. Complete linkage analysis differentiated the populations into six clusters. The most frequently found monoterpene was camphor with or without several satellite compounds such as camphene, 1,8-cineole, pinocamphone, chrysanthenyl acetate, bornyl acetate and isobornyl acetate. In 13 genotypes, camphor concentration exceeded 18.5% and in seven genotypes, camphor was less than 7.2%. Other chemotypes rich in trans thujone, artemisia ketone, 1,8-cineole, or davadone-D were also identified. Davadone-D and a mixed chemotype, containing tricyclene and myrcene, were identified from a Finnish tansy for the first time. Geographically, most chemotypes containing camphor originated from Central Finland, whereas chemotypes without camphor such as artemisia ketone, davadone D and myrcene-tricyclene originated from South or Southwest Finland. Morphologically, the 20 tansy chemotypes based on the groups formed from complete linkage cluster analysis, were compared. The group containing the highest concentration of camphor chemotypes had the tallest shoots. The groups consisting from chemotypes containing davadone-D or artemisia ketone, which originated from Southwest Finland, produced the highest number of flower heads, had the tallest corymb, and were last to flower. Also, the group consisting from chemotypes with a high concentration of camphor and originated from South Finland started to flower late. The correlation between the genetic distance matrices based on RAPD patterns reported previously (Keskitalo et al., 1998. Theo. Appl. Genet. 96, 1141-1150.) and the chemical distance matrices of the present study of the same tansy genotypes was highly significant (0.41, P<0.0001).

Identification and variation of volatile compounds in sternal gland secretions of male koalas (phascolarctos cinereus)

The content of the sternal gland secretion from four male koalas (Phascolarctos cinereus) was analyzed using gas chromatography–mass spectrometry. Volatile fatty acids, aldehydes, ketones, mono- and sesquiterpenes were identified, together with various volatile nitriles and oximes, some of which had not previously been described from any mammalian skin gland. Benzyl cyanide and phenylacetaldehyde oxime were identified as major components of the secretions, together with smaller amounts of the novel 3-methylthiopropanal oxime. The relative abundance of the identified compounds was highly variable between individuals and the scent composition was found to be partly determined by the scent of surrounding conspecifics. Principal component analysis revealed a high similarity between related individuals.