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|標題:||Effects of color extraction methods and pectic enzyme pretreatment of must on the production of red wines|
direct (with skin) fermentation process
juice fermentation after hot extraction process
Abstract The red color of red wine appears attractive and brilliant due to content of anthocyanins from grape skins. In this study, the effects of coloring and flavoring matters extraction on improving red wine quality of red-wine making were examined. In addition, the effects of adding pectinase to increase the yield of must and clarification of wine were also investigated. The direct (with skin) fermentation and juice fermentation after hot extraction, and the optimal temperature of hot extraction and dosage of pectinase (Ultrazyme 100) used in the later process were studied. Different dosages(0~20ppm) of pectinase were added to the crushed, destemmed and pre-filtered must, Black Queen. After 18 hrs, the volumes and residual pectin of the filtrate by air-suction filter were measured. The volume of filtrate which 5.0ppm of pectinase added was 43.3mL/100mL, and no residual precipitated pectin was found. The crushed and destemmed must, Black Queen, was heated from 25 to 85℃ for extraction of red pigments. The absorbance at 420nm, 520nm of wave length, hue (A420/A520) and total pigments were detected, respectively. It showed that the must heated to 65℃ resulted in 0.59 of hue, and 958 mg/L (as anthocyanins) of total pigments. The red color appeared attractive and brilliant. Meanwhile, the pigments were extracted almost completely without oxidation in hot extraction process. Wines made by direct fermentation process and those by hot extraction process were assessed by sensory evaluation using 9-point scale. It showed that there were no significant differences in color, flavor, taste and overall quality of the wines. Both processes are supposed to be appropriate for red-wine making. Further analysis showed content of methanol in wine made by direct fermentation was 211.64mg/L while that made by hot extraction was 59.32mg/L. The pigment-extraction time required was 4~5 days for direct fermentation, but only several hours for hot extraction one. For the sake of low methanol or short extraction time, the hot extract process seems more appropriate to the good quality of red —wine making. Key words: Black Queen, anthocyanins , pectinase, direct (with skin) fermentation process, juice fermentation after hot extraction process, pectin, must, methanol.
|Appears in Collections:||食品暨應用生物科技學系|
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