| Vanilla as a kind of valuable tropical natural spice enjoys the reputation of the king of all perfumes, its distinctive aroma, rich active substances, strong function, widely used in food, medicine and other fields. Our vanilla was mainly distributed in Yunnan and Hainan two provinces, of which the largest planting area in Hainan province. Spice and Beverage Research Institute of China Tropical Agricultural Sciences began the study of vanilla in the last century sixty’s, some progress has been made so far. However, the volatile components in different levels vanilla pods of Hainan was not clear, variety and quality of exotic vanilla pods could not identify, the rate of extraction and low efficiency of tincture of traditional extraction method. Therefore, this paper taken the different levels of vanilla pods of Hainan as the research object, the volatile components were analyzed; The different origins, ages vanilla pods as the research object, comparisoned of the aroma components and drawed the electronic sensory map; On this basis, the experiment selected the highest sensory score of vanilla, the solvent extraction method was optimized through vanillin extraction rate as target.E-Nose coupled with HS-SPME-GC-MS were used to analyze the aroma components of different levels of vanilla pods originated from Hainan. Besides, the contents of main aroma components were detected through high performance liquid chromatography(HPLC). The results indicated that, overall aroma of different levels of vanilla pods could be distinguished by principal component analysis(PCA) of E-Nose. A total of 75 kinds of aroma components of vanilla pods were identified, in which the primary, secondary, tertiary pods were detected as 67, 66 and 60 kinds of components, respectively. Significant differences existed between the relative contents of aromatic species, aldehydes, ketones, acids, alcohols, heterocyclic from different vanilla pods. Aromatics species were the most aroma compounds of vanilla pods. The HPLC results indicated compared with the three levels of vanilla pods, contents of vanillin and vanillic acid were the highest in the primary pods. The content of p-hydroxy benzaldehyde in the secondary pods was highest. The content of p-hydroxy benzoic acid was the highest in the tertiary pods.The quality and the aroma components of different origins, ages, levels vanilla pods were analyzed and a rapid detection method of species and quality of vanilla pods were established by sensory evaluation coupled with E-Nose and HS-SPME-GC-MS. The results showed that sensory scores of vanilla pods ranked as the primary pods of 2013 Hainan>the secondary pods of 2013 Hainan>pods of Comoros>pods of Tonga>pods of 2012 Hainan>the secondary pods of 2013 Hainan>pods of 2010 Hainan>pods of 2011 Hainan. Overall aroma of different origins, ages, levels of vanilla pods could be distinguished by principal component analysis(PCA) of E-Nose. 73, 67 and 69 kinds of volatile components were detected for Hainan, Comoros and Tonga pods, respectively. 65, 60 and 62 kinds of volatile components were detected for 2010, 2011, 2012 Hainan pods, respectively. 67, 66 and 60 kinds of volatile components were detected for the primary, secondary, tertiary pods, respectively. The vanillin were the highest component compared to other components. Significant differences existed between the relative contents of aromatic species, aldehydes, ketones, acids, alcohols, heterocyclic from different vanilla pods. Electronic nose fingerprint were drawed on the basis of this, using electronic map can quickly distinguish vanilla pods species and quality.The vanillin was extracted by solvent method, the experiment which takes grape vanillin extraction rate as target, selecting absolute methanol, acetone, ethyl acetate and isopropyl alcohol as solvent and was found by single factor under the same conditions that absolute methanol extraction rate was the highest 3.28% percent,while the worst effect of isopropyl alcohol 1.09%. Taking methanol as solvent,and vanillin extraction rate as target, selecting liquid ratio, extracting solvent concentration, extracting time and extracting temperature as influnce facters. Based on single factor test, response surface methodology was conducted to optimize the above extraction conditions. The results showed that liquid ratio 4.50 g/100 m L, methanol concentration 81.15%, extracting time 13.00 h, extracting temperature 61.24 ℃, the extraction ratio of vanillin 4.14% in this optimum extraction conditions, in conformity with the predicted value vanillin 4.15%. |
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