The Flavour Analysis Of Two Natural Products (Fennel Essential Oil And Orange)

In this study,two natural products(fennel essential oil and orange)were selected as objects.The aims were to find their characteristic aroma compounds,Sensory attribute and the relationship between them.Moreover,orange was taken as example to study the synergistic effect between aroma substances.According to gas chromatography-mass spectrometry(GC-MS)and gas chromatography–olfactometry(GC-O)analysis,the result showed that a total of 30 aroma components were identified in six fennel essential oils from different origins samples.Among these compounds,?-pinene,?-phellandrene,limonene,?-cubebene,?-caryophyllene,estragole,?-humulene,trans-anethole,?-cadinene and p-anisaldehyde were contributed greatly to the aroma of fennel essential oil.Quantitative analysis showed that the content of trans-anethole was the highest.For four kinds of orange samples,28 odorants were identified and aldehydes constituted the largest chemical group among the volatiles.D-limonene was the most abundant compound and accounted for over 70% of the total content.Moreover,28 aroma substances were detected by gas chromatography–olfactometry(GC-O).According to sensory analysis,the aroma of fennel essential oils was described by 7 sensory terms as spicy,woody,grassy,floral,musty,sweet and green.the aroma of orange was described by six sensory terms,which were fruit note,citrus note,lemon note,flowery note,green note and fatty note.For these two natural products,combined with partial least square method(PLSR),it was found that attributes were covaried well with aroma compounds.In addition,two methods(?-? plot method and S-curve method)were adopted to evaluate the synergism in green orange.57 pairs of binary mixtures were selected to find the possible flavor interaction between aroma compounds.The main results are as following:(1)The most likely outcome of a binary mixture of two different odorants was partial addition effect and only few mixtures displayed hyperaddition.(2)peri-threshold odorants are also able to introduce significant quantitative changes on supra-threshold odour solutions.Finally,it was found that the aroma profile of recombination was closer to that of green orange after adding four peri-threshold aroma substances,which indicates that peri-threshold odorants also played important role in flavor of orange.