1.0 AbstractChanges in anaerobic fermentation of reducing sugars, pH, alcohol production, specific gravity and free sulphur dioxide with Saccharomyces Cerevisiae were investigated. Reducing sugar is proportional and related to alcohol production; increasing the reducing sugars will increase alcohol production. This research question was chosen with the knowledge that it would be complex and challenging for the studentts involved in this investigation, and to understand the changes of physical and chemical characteristics in wine making. Two fermentations were performed using canned apples as a fruit and were manipulated by adjusting the reducing sugars. Fermentation One was controlled, with a standard amount of sugar solution added, while Fermentation Two was varying and had an additional amount of sugar added. The fermentations were performed over a duration of 26 to 42 days with the reducing sugar added on day 4. There were several experimental measurements using a refractometer, pH meter and hydrometer; experimental procedures such as Rankine Aspiration and Titration, Ebulliometry, and a Clinitest Regant Tablet Test.
Results showed that the reducing sugars and specific gravity characteristics decreased with increased alcohol production; there was also decreased pH due to oxidation. Reducing sugar was found to be proportional and related to alcohol production.
2.0 IntroductionWinemaking converts components such as glucose (C5H11O5 - CHO) and fructose (C4H9O4 - CO - CH2OH), into ethyl alcohol (CH3CH2OH) and carbon dioxide (CO2) by the process of fermentation; involving yeast. (Fermentation Process of Wine, 2005) A yeast catalyst is responsible for the breaking down of molecules through the stages of either aerobic respiration involving oxygen or anaerobic respiration without oxygen.
Aerobic RespirationC6H12O6 + 6O2 Ã¢ÂÂ 6H2O + 6CO2 + 2830 kJ/molGlucose/fructose + oxygen Ã¢ÂÂ water + carbon dioxide + energyAnaerobic RespirationC6H12O6 Ã¢ÂÂ 2CH3CH2OH +2CO2 + 115kJ/molGlucose/fructose Ã¢ÂÂ ethanol + carbon dioxide + energyThe cultured yeasts commonly used in wine...