Introduction
Group members
• Leane van Zyl
• Amy Schofield
• Daniel Buchner
• Gaëlle Robertson
We were required to conduct an experiment that explores and analyses the fermentation of the fruits of the Marula tree. We produced two bottles (750ml each) of high quality Marula wine. Our first bottle of wine (Valley Wine) was our control and our second bottle of wine (Maritchi) contained our changed variable.After reading up on various wine recipes, we noticed that many suggested the use of pectinase in the fermentation process. We thus decided to use the addition of litchi pulp and juice as our changed variable in our second bottle of wine because we wanted to test if it would act like a natural pectic enzyme halfway through the fermentation process of the Marula wine. Both wines were assessed by a panel of judges on colour, clarity, bouquet, taste and presentation.
Literature review
Fermentation is a process that involves the breakdown of glucose into pyruvate in the absence of oxygen (anaerobic conditions). Alcohol fermentation takes place in plant and yeast cells where glucose is converted into carbon dioxide and ethyl alcohol in the presence of heat energy. Once these two products are released, the yeast/plant cells die when there is excess alcohol in the solution. (Mann, 2013)
Various factors should be carefully controlled for the best possible reaction outcome. If the temperature of the surroundings is too high or too low, this will kill the yeast. The temperature needs to be approximately between 20 and 25 degrees Celsius for the yeast to thrive. If too much sugar is added, yeast activity will not start or will cease after time. (Pambianchi, 2009) It will then only be able to tolerate a low concentration of alcohol. The solut...
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... variable provided no difference to the original wines and did not produce a substitute for pectic acid. This may be because the lychees did not have sufficient time to ferment as they were only added one week before filtration and thus didn’t fully break down to release pectinase. The pectic enzyme can improve a wine in taste and colour immensely (Kraus, 2010) so therefore instead of a natural substitute, commercial pectinase should be bought and used in the beginning of this experiment instead.
Conclusion
Therefore the hypothesis was proved wrong because the lychees did not provide any improvement to the marula wine with the exception of slightly better aroma in the Maritchi wine. The lychees were unable to produce pectic enzymes during the last stage of the fermentation process and therefore did not provide any colour or taste change to the original marula wine.
While the tube for specimen Cb turned a tannish white in the lower half of the tube while the top stayed the lavender inoculated tube color. Do to this evidence I determined that both specimens Ca and Cb cannot use the process Casein hydrolysis or Casein coagulation due to lack of soft or firm curds in both tubes. Since there was no casein curds formed, I concluded that specimens Ca and Cb also cannot perform the process of proteolysis. My conclusion is supported by the fact that there was no clearing of the medium. I have also determine that neither of my organisms can make the enzymes rennin, proteolytic or even proteases. I know my specimens cannot produce proteases due to the fact that there was no blue coloring in the tubes which means that the byproduct Ammonia was not produced to increase the pH. Since neither of my specimens can make these enzymes, I concluded that my specimens cannot break down lactose or casein. Although I did learn that specimen Cb can reduce litmus due to the evidence that the lower part of the tube turned a tannish white color with a purple ring at the top. This color change from a purple to a white means that the litmus was reduced turning it clear and leaving the white of the milk to show. Finally I know that specimen Ca cannot reduce litmus due to the fact that the tube had no change in
In the span of only a few pages, L.B. Church has given us an overview of the winemaking process. He has done so with sufficient detail for those in the chemistry community to follow along, yet still in a cursory enough manner as to not bog them down with the unnecessary. Written as if it were the procedure of an experiment, he has given enough information for the experiment to be repeated, tested, validated and improved upon. And that is almost assuredly his goal from the very beginning, as it must be for any published author in the chemistry community.
The name for the process of fermentation comes from ‘fervere’, the Latin word meaning “to boil”. Early observers of the process assigned this name to it because as fermentation occurred in barrels containing crushed grapes, being used to create wine, bubbles were produced making it appear as though the mixture were boiling. Yeasts have been secretly creating alcoholic (fermented) beverages since ancient times in Asia, Egypt, Babylon, and many other early civilizations. However, no one knew what made the process work and what made the creation of such fermented beverages possible. When people think of traditional wine makers, it is not uncommon to picture someone standing in a large bucket mashing up grapes with their feet. These ancient wine makers realized that for some odd r...
= I predict that if the concentration is high in the yeast then the speed of oxygen produced in the reaction with hydrogen peroxide will also be high. This is because the amount of yeast that can react with the hydrogen peroxide can get no higher and will have the maximum affect on the reaction. If the concentration is more in favour of water then the amount of oxygen produced will be slow because there is not as much yeast to react with the hydrogen peroxide, giving less oxygen. If the temperature is not in favour of the limits to the yeast then the amount of oxygen produced will be small because the enzyme will have denatured. If the temperature is in favour of the yeast then the amount of oxygen produced will be high because it is at the prime temperature for the yeast to react.
Brewers call the addition of yeast pitching. Once the yeast has been pitched the wort can properly be called beer. Fermentation can last a few days or a few weeks depending of the strain of yeast and the strength of the beer. During the process the yeast reproduce and then metabolize the sugars, making C02, alcohol, and a host of other flavorful and aromatic compounds that add complexity to the beer. During the height of fermentation the beer is capped by a thick creamy foam called kreusen. Once the available sugars have been consumed the yeast cells clump together or floc and fall to the bottom of the
Their table had 15 mL glucose, 10 mL RO water, and 10 mL of yeast which they then placed in an incubator at 37 degrees Celsius. In conclusion, I feel that the absence of RO water in the flask made the enzymes work a little harder than when the RO water was in the mixture of the flask. Comparison #4 is between the Controlled Table and Table #5. The mixture for that table’s flask was 15 mL Sucrose, 10 mL of RO water and 10 mL of yeast, which the flask was then placed in an incubator at 37 degrees Celsius.
Investigating the Effect of Temperature on the Fermentation of Yeast To fully investigate the effect of temperature on the rate of fermentation of yeast Background Information Yeast is a single-cell fungus, occurring in the soil and on plants, commonly used in the baking and alcohol industries. Every living thing requires energy to survive and through respiration, glucose is converted into energy. There are two types of respiration available to living cells are: 1.
Fermentation is one of the process of glycolysis, it is anaerobic, basically this means that it does not use air. Its end product is ethanol, which is a form of alcohol, ethanol differs from alcohol in its chemical composition. The end product of ethanol from glycolysis can be explained by the following equation.
Abstract: Enzymes are catalysts therefore we can state that they work to start a reaction or speed it up. The chemical transformed due to the enzyme (catalase) is known as the substrate. In this lab the chemical used was hydrogen peroxide because it can be broken down by catalase. The substrate in this lab would be hydrogen peroxide and the enzymes used will be catalase which is found in both potatoes and liver. This substrate will fill the active sites on the enzyme and the reaction will vary based on the concentration of both and the different factors in the experiment. Students placed either liver or potatoes in test tubes with the substrate and observed them at different temperatures as well as with different concentrations of the substrate. Upon reviewing observations, it can be concluded that liver contains the greater amount of catalase as its rates of reaction were greater than that of the potato.
The older the wine the costlier it sells. Most of the wines are stored in wooden barrels, as it enhances the taste and colour of the wine. Process & Chemistry in Wine Industry Grape juice contains 79% water & 20 % carbohydrates, 1 % organic acids and, phenolics, vitamins, minerals and nitrogenous compounds. Grape juice gets its flavour from the sugars, organic acids and phenolics, while the vitamins, minerals
An error that occurred in the experiment was during the ceric nitrate test because solution 4 should have produced a color change. During a base hydrolysis of aspartame, aspartic acid, phenylalanine and methanol are produced, therefore the ceric nitrate test should have been a positive for alcohol. A reason that this could have shown a negative result is because methanol is a volatile substance and it could have evaporated out, which would have caused a negative ceric nitrate test
There are hundreds of different species of yeast identified in nature, but the genus and species most commonly used for baking is Saccharomyces cereviae. The scientific name Saccharomyces cerevisiae, means 'a mold which ferments the sugar in cereal (saccharo-mucus cerevisiae) to produce alcohol and carbon dioxide'. Yeast needs energy to survive, and has a number of ways to attain that energy. Fermentation and respiration are two ways The ultimate reaction of importance in this process is the an-aerobic conversion of simple sugars to ethyl alcohol and carbon dioxide during alcoholic fermentation as shown below.
Fermentation is an anaerobic process in which fuel molecules are broken down to create pyruvate and ATP molecules (Alberts, 1998). Both pyruvate and ATP are major energy sources used by the cell to do a variety of things. For example, ATP is used in cell division to divide the chromosomes (Alberts, 1998).
Lactic acid have more growth requirements than then normal bacteria since it was evolved in nutrient-rich environments. Lactic acid bacteria have diverse mechanisms for creating the energy needed to support and sustain biological activities. The availability of organic acid in the fruit can be important in allowing growth and metabolism. As lactic acid bacteria have the ability to produce large amount of acids, they often inhibit the development of other bacteria in juices and are able to cause their own autolysis. Excessive clarification and pre treatment of the fruit during the process of sending the fruit to the market which removes many of the natural yeasts and flora. The chemical compsition of juice also affect the rate of fermentation. Fruits generally tend to contain sufficient substrate (soluble sugars)that allow for the yeast and bacteria to fermented , so it can be said that because the fruits used did not show a very high increase in acidity it did not provide a sufficient substrate for the lactic acid bacteria that is present on the fruit to be used for fermentation.Temperature has an impact on the growth and activity of different strains of yeast. At temperatures of
Alcohol is a class of organic compounds that is characterized by the presence of one or more hydroxyl groups (-OH) attached to a carbon atom. Alcohol was unknowingly produced centuries ago when fermentation occurred to crushed grapes (Pines, 1931). In today’s society alcohol is produced for the use of household products such as varnishes, cleaning products, but is more commercially important in the liquor business. A chemical process called fermentation accomplishes the production of ethanol, the alcohol or liquor. From there, the ethanol goes through distinct processes to become the dark and clear liquors on the store shelves.