Purpose To allow for fermentation of the yeast, Saccharomyces Cerevisiae, in Grape and Apple juice. Materials provided Test-tube containing Grape juice and a Durham tube Test-tube containing Apple juice and a Durham tube Plate culture of the yeast, Saccharomyces Cerevisiae Sterile swabs Method As per manual Results ·Sediments of the cell sunk to the bottom of the test-tube. ·The Durham tube had risen to the top of the test-tube. ·There was a strong smell of alcohol from the fruit juice.
·Bubbles could be seen in the test-tube. Apple juice|Grape juice| pH|4|3| Comments and Conclusions After close examination of the two test-tubes, it was clear that fermentation had taken place in both the Apple and Grape juice. Gas had been collected in both of the Durham tubes and had caused them to rise to the top of the test-tubes. There was also a strong smell of alcohol from both the juices now and the colour of the juices had changed slightly too, becoming a little bit darker than the colour of the juices before fermentation had occurred.
The bubbles that were visible in the test-tubes were trapped CO2, the result of yeast fermenting sugars in the grape and apple juice. From all of the above we can definitely conclude that yeast fermentation occurred in both the Apple and Grape juice. Fermentation Fermentation is the conversion of sugar into an acid or an alcohol. It can also refer to the use of yeast to change sugar into alcohol. Fermentation occurs naturally in many different foods given the right conditions, and humans have intentionally made use of it for many thousands of years.
Fermentation was first used to create alcoholic beverages such as wine and beer. The fermentation of foods such as milk and various vegetables probably happened sometime a few thousand years later. The general principle of fermentation is the same across all of these drinks and foods. Beer is made from a grain such as wheat or barley. The grain is germinated, dried and made into a mash. The mash is then mixed with hot water and the fermentation process begins when yeast is added in which eats the sugar present in the mash and converts it into carbon dioxide and alcohol.
After a few weeks of fermentation and a further period of conditioning, the beer is ready to be filtered and consumed. Wine is created using grapes which are crushed to release the sugar-rich juices to which yeast is then added and the fermentation process begins. A chemical reaction for fermentation is the following: C6H12O6 ? 2(CH3CH2OH) + 2(CO2) Fermentation is a biological process involving yeast that converts sugars into alcohol. The overall chemical reaction for fermentation is the conversion of a single molecule of glucose (sugar) into two molecules of ethyl alcohol, and two molecules of carbon dioxide.
Saccharomyces Cerevisiae is also used in bread making. The yeast ferments sugars present in the flour or added to the dough, giving off carbon dioxide (CO2) and alcohol (ethanol). The CO2 is trapped as tiny bubbles in the dough, which rises. The yeast does this to gain energy from the breakdown (fermentation) of carbohydrates. This can be seen in the following diagram: Saccharomyces Cerevisiae is also frequently used as a source of vitamins and minerals. It is rich in B vitamins, chromium and selenium.
B vitamins help maintain the health of your hair, skin, mouth, liver and eyes. They also aid in breaking down fats, proteins and carbohydrates, which your body uses for energy. In addition, B vitamins support your nervous system and help support the muscles that you use for digestion. Some research suggests that supplementing with chromium may help control blood sugar levels in people who have diabetes and reduce the amount of insulin that they need to take.
