| Summary: | 碩士 === 大葉大學 === 生物產業科技學系碩士在職專班 === 94 === Black Queen is the only grape variety for making red wine in Taiwan, but its high acidity, influenced by factors such as variety and planting environment, has resulted in the production of wine with biting mouthfeel and inferior quality. Different chemicals (calcium carbonate, potassium hydrogen carbonate, potassium bitartrate) and malolactic fermentation bacteria were used to deacidify the wine into a product with high quality, low acidity and mellow mouthfeel.
Direct addition of calcium carbonate, potassium hydrogen carbonate and potassium bitartrate to the various stages of winemaking to neutralize the organic acids in the wine can achieve the deacidification effect. A dosage of 2.01 g/L of calcium carbonate or 2.55 g/L of potassium hydrogen carbonate gave the best deacidification effect when chemical deacidificants were exploited. The red wine deacidified with 2.55 g/L of potassium hydrogen carbonate was most acceptable in the sensory test.
The malic acid in the red wine couldn’t be completely converted to lactic acid during malolactic bacteria fermentation. In practice, only one-third of malic acid was converted. The optimum conditions for malolactic fermentation included an inoculum of 5%, fermentation temperature of 20℃, and addition of 0.2 g/L of malolactic nutrients. The commercial multiple strain product, Biolact Acclimatée® was a batter source of malolactic bacteria than single strain Oenococcus oeni BCRC 16064 in deacidifying red wine.
In the experiments combining the chemical deacidificants and malolactic bacteria to deacidify red wine, two commercial malolactic bacteria products, Biolact Acclimatée® and Lalvin X-3® have similar effect. Both deacidified red wine to a total acidity content of 0.85 g/100mL, and had highest scores of taste and overall preference with significant difference.
In conclusion, treatment with chemical deacidificants combined with malolactic bacteria have the best deacidifiction effect on red wine and resulted in improved acceptability of the wine. The deacidified red wine was even more acceptable after 3 months of storage.
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