5. A wine maker informed you that his must is deficient in nitrogen and does not

Question

5. A wine maker informed you that his must is deficient in nitrogen and does not support efficient fermentation of sugars. What advice would you give to a wine maker whose grape variety is deficient in nitrogen sources?

6. How does oxygen influence yeast growth and fermentation during wine production?

7. Explain flavor development during wine ageing and storage. Name the microorganisms involved in malo-lactic fermentation.

8. List three fining agents for wine clarification.

9. Briefly describe methods employed to preserve wine. What is principal demerit of wine pasteurization.

10. Briefly discuss microbial spoilage of wine.

11. A local grape farmer produces wine for some bars in your community. The farmer has a serious problem with maintaining the quality of his wine. He is losing customers because it is always a different taste. The wine making process was evaluated for contamination but it was not the cause. Genetic analysis of his yeast over time revealed significant variation. As an industrial microbiologist, give a brief description of your advice to this wine produce

Explanation / Answer

5. The wine maker could add Nitrogen to the must in the form of Diammonium Phosphate or use cultured yeast which is high in Nitrogen with a high temperature and alcohol tolerance.

6. Oxygen makes the yeast dormant before fermentation hence the amount of oxygen is controlled so that the fermentation process takes place in order to give alcohol.

7. Before ageing and storage flavour development takes place in which different flavours are added to the wine Using bacteria that converts one type of acid to another. FOr fruity smell ( green apple ) Malic acid is used but in order to make it buttery and smooth Lactic acid is used.

Microorganisms involved in Malolactic fermentation include species of Lactic acid bacteria , Lactobacillus and Pediococcus.

8. three fining agents for wine clarification are (a) Egg whites (b) Betonite clay (c) Activated charcoal

9. Private preserver which includes inert gas preserver and vacuum pump preservation in which all the air is pumped out to preserve the wine.

Prinicipal demerit of wine pasteurization is Oxidation may occur which deteriorates the quality of wine.

10. Due to the presence of high content of alcohol and less pH (high acidicity) only yeasts and lactic bacteria can grow but due to unhygienic winery conditions and poor winery surfaces other moulds may grow which are determined by techniques of microscopy or agar plating. Microbial spoilage is used to to prevent the development of microorganisms in the wine than to remove the effects of spoilage once it has occurred

11.

Genetic variation of his yeast occurs over time due to which the wine tastes different. This occurs mainly due to the ageing of yeast . In order to produce quality wine the yeast should be fresh and young and should be stopped using when it starts to age.

Related Questions

Navigate

• Browse (All)
• Browse 5
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.