Question

1. How does pasteurization contribute to the production of wine? how about when a good taste is preferred?

2. Do all microbes ferment sugar in the same way to generate products such as wine? why or why not

Answer 1

Pasteurization is defined as the partial sterilization of the product such as milk or wine to make it safe for consumption and also improve its keeping quality. This pasteurization process is widely used for in wine production cycle.One of the difficulties related to wine making processes is the possibility of unwanted microbiological contaminations that can be seen at different stages of the wine-production cycle. In order to avoid these problems, wine making industries uses sulfitation with well known problems related to the effect of sulphites on health and the need to indicate on the label caption Contains Sulphites for the level of sulphites above 10mg/L

Contribution of Pasteurization:

Pasteurization heat treatment process is used for the young wines, instead of short term consumption. Aged wines for not preferably pasteurized in order to keep them alive. Pasteurization helps in reducing health risks caused by pathogenic microorganisms sensitive to heat, such as bacteria in the vegetative form, fungi and yeasts. This process is applied to wine in order to stabilize it from bacterial and enzymatic point of views and bring the point at high temperatures in few minutes. It depends on the degree of pollution of the product and resistance by the microorganisms to the treatment. Pasteurization performed at 60 degree celsius for 10 minutes destroys the yeast and eliminates the bacteria at 60 degree celsius for 45 seconds and also destroys the enzymes at at 70 degree celsius for 2 minutes. The effect of pasteurization depends on the characteristics of wine, on its alcohol degree, pH, presence of carbon dioxide, and content in sulphur dioxide. With a given pasteurization cycle, the destruction of microorganisms present in the product to be treated is obtained. Classical industrial pasteurizers are trying to preserve the organoleptic characteristics of the product.

Microbes:

Fermentation occur when microorganisms consume susceptible organic substrate as part of their own metabolic processes. We can see Industrial Fermentations used in food industries like Lactic acid bacteria (Vegetables, Dairy products, fruits), Lactic acid bacteria with other microorganisms( Dairy products), Acetic acid bacteria( wine), Yeasts, Yeasts with lactic acid bacteria, Yeasts with acetic acid bacteria, Mold and other organisms. Sugar fermented by yeasts, such as Saccharomyces cerevisiae and Saccharomyces ellipsoideus, yields ethyl alcohol and carbon dioxide. Lactose (milk sugar), fermented by Streptococcus lactis bacteria, gives lactic acid, which curdles the milk to yield cottage cheese and curd from which other cheeses can be made.Acids produced from fermentation, in the presence of oxygen, can be further broken down by molds. When this happens, the preservative action of the acid against other microorganisms is lost.Proteins broken down by proteolytic bacteria such as Proteus vulgaris and other organisms yield a wide range of nitrogen-containing compounds that give putrid, fishy, or decayed odors to food. Lipids broken down by lipolytic bacteria such as Alcaligenes lipolyticus and other organisms yield fatty acids. These and their subsequent breakdown products contribute to rancid odors or the characteristic odors of some aged cheeses.Low-acid foods supporting growth of Clostridium, botulinum may contain toxins produced by this bacterium. This food-poisoning organism will not grow in fermented foods high in acid.