| The norisoprenoids from carotenoid degrading have great contribution to the fragrance quality of wine. The researches of carotenoid degradation have great help to distinguish of sources of aromatic compounds in wine and improvement of wine quality. The sea-buckthorn wine is a special kind of wine produced according to the technology of wine using sea-buckthorn juice as raw material. These products are insufficient in fragrance quality, specially lacking in norisoprenoids, which is a main quality flaw. So the research of improvement sea-buckthorn wine fragrance quality is extremely essential. The simulative research can decompose the complex food system into the simple simulation system, which is an important way to study the mechanism of carotenoid degradation and production of aromatic compounds. At present, there are some reports about carotenoid degradation, but most simulation systems were carried out under drastic conditions (high temperature and short time), which were far from natural conditions of vintage. In order to get useful information to explain the relationship between carotenoids degradation and norisoprenoids formation during wine vintage, the degradations ofβ-carotene at simulating conditions of wine vintage have been studied in this research.The aqueous model systems at ambient temperature for a relatively long time were designed to studyβ-carotene degradation at natural sea buckthorn wine production, so the factors of effecting on theβ-carotene degradation and formation of norisoprenoids during the wine production will been identified. At same time, the biodegradation ofβ-carotene were also studied in detail. Firstly, the aqueous model systems, which can reflect existence condition ofβ-carotene in sea buckthorn juice and wine, were established. Secondly, the methods of determination ofβ-carotene in different aqueous system were studied, which is the base of this research. Thirdly, the contents of volatile compounds of sea buckthorn wine were analyzed, which is the first report results in international research. Fourthly, the rule and compounds ofβ-carotene degradation have been studied, especially; the microbialβ-carotene degradation in raw juice and fermentation of juice has been systematically studied. The microorganism presenting in raw juice having high efficiency to degradeβ-carotene has been isolated and identified. 1) The model aqueous system simulating existence condition ofβ-carotene in production of sea buckthorn wine were set up using dichloromethane and Tween 80 as emulsification; the methods of quickly determination ofβ-carotene in aqueous phase system were established. The ethyl alcohol can affectβ-carotene degradation in aqueous phase system.2) There were 50, 53, 38 and 39 compounds in the volatile fractions of sweet, dry sea buckthorn wine, juice and must comprising of higher alcohols, ethyl esters, acetates, fatty acids and carbonyl compounds, which may contribute to the typical flavor of sea buckthorn wine. The varieties of products, time of storage and fermentation have effect on the type and contents of volatile compounds. There are few contents of norisoprenoids fromβ-carotene degradation in sea buckthorn wine.3) The kinetics ofβ-carotene oxidation was first order pattern in the pure water or water/ethyl alcohol system, but it is zero order patterns of degradation without foreign oxidant. The temperature dependent rate constant of auto oxidation is 0.031 without any foreign oxidants. The temperature dependent rate constant of oxidation is 0.071 under influencing of foreign oxidants in pure aqueous system, and it is 0.0458 in water/ethyl alcohol. Temperature was the major factor affectingβ-carotene degradation in aqueous solution. Alcohol also showed an effect onβ-carotene degradation. The activation energy ofβ-carotene degradation is 37.434KJ/mol. The foreign oxidants have less effect onβ-carotene degradation. Theβ-carotene degradation proceeded more quickly in sea buckthorn raw juice than in must and wine. Six norisoprenoids fromβ-carotene degradation were found in aqueous system, which were 3,5,5-trimethyl-2-cyclohexen-1-ol, 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-ol, 2,2,6–trimethyl -cyclohexanone, 3,5,5-trimethyl-2-cyclohexen-1-one, 3,4,4-trimethyl-2-cyclohexen-1 -one and 2,6,6-trimethyl-1-cyclohexene-1-carboxaldehyde. There are different kinds and contents of norisoprenoids in different aqueous systems.4) The bacterium having highly effective of degradingβ-carotene has been isolated and identified as staphylococcus strain. The results of researching liquid culture medium showed that it can secrete enzyme degradingβ-carotene. The active protein component, which has activity ofβ-carotene degradation, has been obtained after the processing of ionic exchange column and the molecular sieve chromatographic. This protein fraction can present the protein banding in the SDS- polyacrylamide electrophoresis; this enzyme do not only causesβ-carotene degradation, but also produce aromatic compounds fromβ-carotene degradation. There are two different reaction patterns about enzymatic degradation ofβ-carotene in different period. It is zero order reaction patterns at early period, but it is first order patterns after 30min. 5)β-carotene can be cleaved symmetrically at the C7-C8/C7′-C8′and C9-C10/C9′-C10′. There are different compounds under different oxidative condition. The norisoprenoids are 2,6,6-trimethyl-1-cyclohexene-1-carboxaldehyde, ionone, 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-ol, terpineol, 2,2,6-trimethyl cyclohexanone, 3,3,5-trimethyl-2-cyclohexen-1-one, 3,4,4- trimethyl-2-cyclohexen-1-one and actinidiol so on.6) Caroteniod of carrot can be degraded by the microorganism which is obtained from sea-buckthorn juice. The condition of incubation and components of culture medium, such as temperature, time, speed of shaker, carbon source and nitrogen sources can influence the degradation of caroteniod from carrot juice. There are norisoprenoids produced by degradation of carotnoid from carrot juice.
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