Thesis (M.Sc.)--Chulalongkorn University, 2008

This research investigated fermentation profiles of Sai Nam Phueng tangerine (Citrus reticulata) wine and evaluated the acceptability of tangerine wine formulation. The fermentation profiles of 3 juice concentrations (30%, 50%, and 100%) containing approximately 25% reducing sugar and 0.05% diammonium phosphate fermented under 30°C by single and mixed cultures (Saccharomyces cerevisiae and Saccharomyces bayanus) were investigated to find a proper condition for basic tangerine wine production. The yeast population, reducing sugar and alcohol content were monitored everyday during the fermentation until alcohol reached 12%. Based on fermentation profile evaluation, the fermentation of single culture of S. bayanus using 100% juice as a substrate could perform the fastest fermentation rate. It utilized 3.70% sugar/day and generated 2.61% alcohol/day, consequently alcohol reached 12% within 5 days. After the clarification, the fermented juice contained 3.55% reducing sugar, 12% alcohol, and 0.32% titratable acidity. However, sugar amount in the tangerine wine from this condition still remained in large amount. This was obstacle for wine formulation. Therefore the fermentation profile of S. bayanus in 100% must containing lower reducing sugar approximately 16%, 19%, and 22% were investigated. The must containing 22% sugar was selected to produce a basic wine due to its appropriate fermentation profile and acceptable flavor. The basic wine made from this condition after clarification contained 1.93% sugar, 11% alcohol, and 0.38% titratable acidity. The selected basic wine was then formulated by adjusting sugar content (2%, 4%, and 6%) and acidity (0.5%, 0.7%, and 0.9%). The acceptability of the 9 tangerine wine formulations were evaluated a Balanced Incomplete Block design with 108 assessors (54 females and 54 males). Each assessors evaluated 4 samples. The acceptability of the tangerine wine samples evaluated by female and male groups was significantly different (p≤0.05) therefore the data were analyzed separately for each gender. For the female group, sugar content, acidity and their interaction significantly (p≤0.05) influenced on the product acceptability. The formulas with 6% sugar had higher liking scores than the lower levels in every level of %acidity. The formula with 6%sugar and 0.5%acidity was the most accepted with the mean liking score 7.13±1.33. For the male group, only the %acidity had significantly (p≤0.05) effected the liking score. The tangerine wine containing 6%sugar and 0.9%acidity had the highest liking score (5.75±1.73). These results showed the higher preference in female over male group, therefore this product could suit for female while male perception was neither like nor dislike the product because its score was lower than six points in the hedonic scale. The experience in fruit wine drinking was not significantly (p>0.05) effect the acceptability of the product. Shelf life of the most accepted tangerine wine formula storaged under refrigerator and room temperature was longer than 2 months.