Lab quiz 7

what makes beer

-are produced when the sugars in plants are fermented by yeast. Beer is made from four basic ingredients: Barley, water, hops and yeast. The basic idea is to extract the sugars from grains (usually barley) so that the yeast can turn it into alcohol and CO2, creating beer

What does lactic acid do in the production of sauerkraut?

-inhibiting the growth of other bacteria that may decompose or spoil the food. -can convert carbohydrates to lactic acid plus carbon dioxide without the need of oxygen -know this one for the quiz, produces different flavors and produces organic acids that lower the pH

Why do we add sugar to beer?

...sugar is what turns into alcohol during fermentation

scientific name of yogurt bacteria

Lactobacillus bulgaricus Streptococcus thermophilus.

scientific name of sauerkraut bacteria

Leuconostoc and Lactobacillus

what are the ingredients in beer

Malt prepared from germinated and dried barley grains § Hops dried flowers of the hop plant § Malt adjuncts starch or sugarcontaining materials added in addition to the carbohydrates in the malt § Starch adjuncts corn and corn products, rice, wheat, barley, sorghum grain, soybeans, cassava, potatoes, etc § Sweet adjuncts materials such as sugars and syrups

Why is a water-filled plastic bag used to cover the cabbage in the production sauerkraut?

The cover inhibits the entry of oxygen into the mixture and allows the anaerobic fermentation to occur

What is the purpose of adding corn sugar to each sterile bottle before adding the beer and capping?

The sugars are fermented by the yeast and gives beer its taste

What would happen if a plain, solid rubber stopper was used to tightly seal the beer fermentation vessel?

There would be no oxygen left and the sugars are metabolized to ethanol and carbon dioxide (which gives beer it's taste)

example of food produced by microbiology other than yogurt, beer, saurkraut

beer, wine, cheese

types of food made with microbiology

cheeses, yogurt, bread, sauerkraut, wine and beer.

Describe how you would show that Streptococcus and Lactobacillus are present in commercial yogurt?

do a gram stain. both are gram positive bacteria and will appear purple under the microscope

Byproducts of fermentation

end products may be a mixture of organic wastes including organic acids that lower the pH, various amines, that raise the pH, or ethanol. Ethanol, carbon dioxide, and lactic acid

If yogurt were gram stained, what result would indicate the yogurt is contaminated?

gram negative rods would indicate that our yogurt is contaminated, so the bacteria will show up red

why is NaCl added to cabbage?

to provide the optimum environmental conditions for growth, helps extract juices, and to inhibit the growth of molds that would ruin the cabbage