Alkanol’s are formed when a hydrogen atom from an alkane compound is replaced with an OH or hydroxyl group (SMITH, 2006) . To get this alcohol the wine needs to undergo a process called fermentation. Fermentation is a process including a microorganism called yeast breaking down a molecule without using oxygen to produce energy. It is a process in which sugar is consumed by yeast to produce sugar. It can be said that the more sugar there is in the grapes the more alcohol content there will be in the resulting wine.
In order to make yogurt, bacteria called Lactobacillus bulgaricus and Streptococcus thermophilus produce lactic acid in the milk culture, which causes the pH to decrease and makes the environment acidic. Ethanol fermentation uses yeast to break pyruvate into acetaldehyde, which makes carbon dioxide. Through the oxidation of NADH glucose becomes ethanol and carbon dioxide. Just like Lactic acid fermentation, Alcohol fermentation utilizes a molecule of glucose that goes though glycolysis and produces two molecules of pyruvic acid and two molecules of ATP. The two molecules of pyruvic acid are converted into two molecules of acetaldehyde and two molecules of CO2.
The carbon dioxide is used in beer and wine manufacture. In sparkling wines and beer some of the carbon dioxide is retained in the finished beverage. The fermentation of wine is initiated by naturally occurring yeasts present in the grapes. One yeast cell can ferment approximately its own weight of glucose per hour. Yeast is also used in making bread.
Throughout this experiment ethanol is the alcohol which is produced during the fermentation process of sugar which is present in the grape must or juice. Figure 1: Chemical structure of Ethanol (Wikimedia, 19 July 2009) Yeast is a single celled living organism which is necessary in the process of fermentation of the grape must. Invertase, an enzyme is present in yeast acts as a catalyst to speed up the chemical reaction where sucrose is converted into fructose and glucose. (Donal O’Leary, 2000) Figure 2: The word and balanced equation of the conversion of Sucrose to simple sugars (Donal O’Leary, 2000) Another enzyme which is found in yeast is known as Zymase. It is this enzyme present in yeast which converts the glucose and fructose produced into ethanol and carbon dioxide.
• Milling – The first step of the process is crushing the malt. This breaks apart the grains, exposing the starchy ball inside and making it accessible to the brewer. The grains are only lightly crushed, leaving the hulls intact to serve as a filter bed for the lautering process later on. FIG.-MILLING MACHINE FIG.- CRUSHED BARLEY • Mashing –Mashing is the process by which the brewer extracts fermentable sugars from the grain. Basically it consists of steeping the grains in water at temperatures between 140° and 160° Fahrenheit for a period of sixty to ninety minutes at a thickness similar to porridge.
This procedure is controlled carefully so as to break the grain while keeping the husk as large and as intact as possible. Milling allows the grain to absorb the water it will be mixed with later as the water will extract sugars from the malt. The malt will now be mixed with warm water in the mash tun. This vessel holds the grain and water mixture for a period of time. Two important things will take place in this step.
The first of them is steeping. In this step barley seeds are allowed to soak in water for about 40 days. The second step is germinating. The barley plant in allowed 3 or 4 days to sprout. In this process enzymes are produces which break down the starch (large molecules) in to molecules of shorter length.
The fermentation of wine through the use of yeast bacteria enables the production of alcohol. This process occurs through the conversion of sugars such as glucose and fructose into ethanol alcohol. Alcohol is only present within grape juice in trace amounts while within wine, the average alcohol content is 12.5% (Wansbrough, 2008). Inversely, there is approximately 11% of fructose and 10% of glucose within grape juice, while there is on average, approximately 0.07% fructose and 0.06% glucose within dry wines (Wansbrough, 2008). The conversion of glucose to ethanol can be represented with this equation: C6H12O6 2C2H5OH + 2CO2
The NADH then left its hydrogen onto the second carbon molecule creating ethanol. The overall chemical reaction are as follows : C6H12O6 + 2 ADP + 4 H+ → 2 C2H5OH + 2 CO2 + 2 ATP + 2 H2O glucose ethanol energy The most important alcoholic fermentation in industry is wine. It is produced by fermentation of fruit juice. Beer or ale is also one of the important alcoholic fermentation that is produced by fermentation of malted grains and distilled beverage, produced by concentrating alcohol from fermentation by distillation. OBJECTIVES To observe alcohol production of yeast.
Introduction: Fermentation a metabolic process with occurs in the absence of oxygen molecules also known as an anabolic reaction. It is a process of glycolysis in which sugar molecules are used to create ATP. Fermentation has many forms the two most known examples are lactic acid and alcoholic fermentation (Cressy). Lactic acid fermentation is used in many ranges from food production such as bacteria to its use by fatigued muscles in complex organisms (Cressy). When experimenting with organisms such as yeast which was done in this experiment you follow the metabolic pathway of Alcoholic fermentation (Sadava).