Multiple Choice (Chapter 12)

Chocolate-covered cherries are made by using a microbially produced enzyme called: a) invertase b) pectinase c) proteinase d) chocolatase

a) invertase Reason: Invertase is the enzyme made by yeasts and species of Bacillus that softens the cherries and produces the final product. B is incorrect because pectinase is an enzyme that breaks down pectin. C is incorrect because proteinase is an enzyme that breaks down protein. D is incorrect because there is no enzyme called chocolatase.

Bread, beer, and wine are all produced by the microbe known as: a) Acetobacter aceti b) Saccharomyces cerevisiae c) Penicillium roqueforti d) Aspergillus oryzae

b) Saccharomyces cerevisiae Reason: Saccharomyces cerevisiae is a yeast used to make substantial amounts of carbon dioxide and/or alcohol during metabolism. A is incorrect because Acetobacter aceti is used in the production of vinegar. C is incorrect because Penicillium roqueforti is used in the production of Roquefort cheese. D is incorrect because Aspergillus oryzae is used in the production of soy sauce.

Sauerkraut is produced under what type of conditions? a) aerobic b) anaerobic c) microaerophilic d) it doesn't matter

b) anaerobic Reason: Sauerkraut is made in a closed container to eliminate oxygen and stimulate anaerobic conditions. A is incorrect because aerobic conditions would have air present. C is incorrect because microaerophilic refers to conditions with a low oxygen concentration. D is incorrect because anaerobic conditions are needed for production of the correct microbial products.

The holes in Swiss cheese are a result of microbial production of: a) oxygen b) carbon dioxide c) lactic acid d) vinegar

b) carbon dioxide Reason: Carbon dioxide is a by-product produced by bacteria in the curds, accumulating as the holes in the cheese. A is incorrect because bacteria don't produce oxygen as a by-product of fermentation. C is incorrect because lactic acid formation is used to make the original curds of the cheese. D is incorrect because vinegar does not play a role in the formation of Swiss cheese.

In order to produce vinegar bacterial cultures are added to tanks containing fruit juice and: a) potato skins b) wood shavings and gravel c) soybeans d) shredded cabbage

b) wood shavings and gravel Reason: The bacterium that makes vinegar multiplies on the wood shavings and gravel, producing acetic acid from the fruit juice. A is incorrect because potatoes can be used to produce unflavored ethyl alcohol. C is incorrect because soybeans are used to produce soy sauce. D is incorrect because shredded cabbage is the initial ingredient of sauerkraut.

Koji is: a) the "mother dough" carried over to make new batch of bread b) grape juice inoculated with yeasts during production of wine c) a soupy mixture of soybeans, rice, and wheat bran inoculated with fungi in soy sauce production d) the fermentation of rice in the initial step of sake production

c) a soupy mixture of soybeans, rice, and wheat bran inoculated with fungi in soy sauce production Reason: Koji refers to the soupy mixture used to start soy sauce production. A is incorrect because there is no special name for the small amount of dough saved to make a new batch of bread. B is incorrect because the yeast inoculated grape juice is referred to as must. D is incorrect because sake production does not begin with a starter material.

A yeast's ability to produce naturally leavened bread depends largely on what substance in wheat flour? a) casein b) lactose c) gluten d) wort

c) gluten Reason: Gluten is an elastic protein that helps trap the gas produced by yeast. A is incorrect because casein is the major protein found in milk. B is incorrect because lactose is the major carbohydrate found in milk. D is incorrect because wort is the name for the liquid derived from barley grains during beer production.

In beer production, the liquid to which yeast are added is called: a) must b) malt c) wort d) lager

c) wort Reason: Wort is the name of the liquid portion after malt is ground with water. A is incorrect because grape juice inoculated with yeast is referred to as must. B is incorrect because malting is the predigesting of barley grains. D is incorrect because lager is the name of a type of finished beer.

Which of the following foods is not a product of microbial fermentation? a) brandy b) cheese c) soy sauce d) all of the above are results of microbial fermentation

d) all of the above are results of microbial fermentation Reason: Many different foods are produced as a result of microbial fermentation; brandy, cheese and soy sauce are but a few examples. A, B, and C are incorrect because each answer alone is not the only food produced using microbial fermentation.

Cheeses are ripened by the addition of ________ to the curds. a) lactic acid b) carbon dioxide c) salt d) cultures of microbes

d) cultures of microbes Reason: Different microbes, such as bacteria, yeasts, and molds, can be added to curds to produce a variety of flavors. Development of these flavors is called ripening. A is incorrect because lactic acid is a substance produced by microbes during curd production. B is incorrect because carbon dioxide is produced by microbes during the ripening period. C is incorrect because salt is added to the curds before the ripening period.