| Sea-buckthorn includes 100 kinds of active materials and has very rich nutritional value. It also has outstanding ecological benefits and economic value. The developing techniques for sea-buckthorn resource has developed quickly now in China. It has already been used in producing functional food, cosmetics and drugs widely. In the utilization of sea-buckthorn berry, people pay much more attention to the extraction of oil and total flavonoids. Sea-buckthorn juice and pulp have not been used sufficiently yet because of the high acidity and low sugar content. The goal of this paper was to brew the healthy sea-buckthorn vinegar successfully by using the sea-buckthorn pulp. We screened a good yeast strain for brewing sea-buckthorn wine, optimized the technical conditions of liquid alcohol-solid acetic fermentation and analyzed healthy compositions in sea-buckthorn vinegar. The main research techniques and conclusions are as follows:1. Five basic components in sea-buckthorn juice and pulp were analyzed, including soluble solids content, pH, total sugars content and reducing sugars content, then we studied fermentable sugars in sea-buckthorn pulp. Acidity and pH had not diverged much between sea-buckthorn juice and pulp, but the latter had more soluble solids content, total sugars content and reducing sugars content. The contents of glucose, fructose,xylose and sucrose are 2.34%,3.05%,0.23% and 0.16% respectively, and total contents is 46.9% of reducing sugars content.2. An excellent yeast strain called Rl was screened for brewing sea-buckthorn wine from sea-buckthorn juice. With plenty of testing experiments such as using YPD culture medium with the same pH as sea-buckthorn juice, the gas formation ability, the alcohol yield and the fermentation capacity, as well as the sensory evaluation of sea-buckthorn wine fermented by different yeast strains, Rl was screened from ripe outer covering of sea-buckthorn. It was suitable for alcohol fermentation in sea-buckthorn juice with high acidity and low sugar degree and no constituent being.adjusted. It started fermentation quickly with the strong ability. The quality of sea-buckthorn wine produced by Rl was excellent with a clear and transparent wine body, a wine-red color and luster, and a typical model taste of the sea-buckthorn wine. Strain Rl was suitable for producing of sea-buckthorn wine and vinegar. Strain Rl was identified by molecular biological method as a new strain of Saccharomyces cerevisiae.3. The technological conditions of liquid alcoholic-solid acetic fermentation (L-S) were optimized. The result showed that the optimal conditions for liquid alcoholic fermentation were at 28℃, yeast inoculation ratio 10% for 6 d. Under these conditions, sea-buckthorn wine with 6.72% could be obtained. The optimal conditions for solid acetic fermentation were at 30℃, initial alcohol 6.72%, and acetic acid bacteria inoculation ratio 10% for 12 days. Under these conditions, sea-buckthorn vinegar with 6.15% could be obtained.4. Healthy compositions in sea-buckthorn vinegar were analyzed. Compared with sea-buckthorn pulp, total polyphenols, total flavonoids, the polypeptide, Vc, the components and contents of amino acids and organic acids were analyzed. During sea-buckthorn vinegar fermentation, the contents of total polyphenols, total flavonoids, and Vc dropped. The contents of the polypeptide and amino acids increased, especially the latter. Sea-buckthorn pulp were high in malic and quinic acids, the contents were 0.66.g/100mL and 0.50 g/100mL, and low in formate, tartaric, citric, amber; acetic acids. Acetic acid was the main constituent of sea-buckthorn vinegar, its content reached 3.96g/100mL.The contents of malic, quinic, formate, tartaric, citric acids dropped. The contents of lactic acid increased. Not much seemed to have changed in the contents of amber acid. |
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