Description and references
The moist, living cells of a fungus or fungi
whose usual and dominant growth form is unicellular. The term yeast
is not one with an exact botanical meaning, see Henrici's Molds, Yeasts and Actinomycetes (New York, 1947) p 264 sqq. Normally produces alcoholic fermentation
in fluids contg sugar. Moist yeast is usually combined with a starchy
or absorbent base and comes on the market in the form of white or
yellowish-white, soft, easily broken masses of a characteristic, slightly
sour odor. Description of a modern process of manuf: Schultz, Swift, US 2717837 (1955 to Standard Brands).
Properties
The dried yeast of pharmacopoeias consists of
the dry cells of any suitable strain of Saccharomyces cerevisiae Meyen, Saccharomytaceae or Candida utilis (Hanneberg)
Lodder and Kreger-Van Rij, Cryptococcaceae (torula yeast),
usually obtained as a by-product from the brewing of beer made from
an extract of cereal grains and hops. The yeast cells are washed
free of beer and dried, and may be debittered. These yeasts are commonly
known as “Brewer's Dried Yeast” and “Debittered Brewer's Dried Yeast.”
Dried yeast may be obtained also by growing suitable strains of yeast,
using media other than those required for the production of beer,
and under appropriate environmental conditions. The yeast thus obtained
is commonly known as “Primary Dried Yeast.” Dried yeast that fulfills
pharmacopeal requirements contains not less than 40% protein, and,
in each gram, the equivalent of not less than 0.12 mg of thiamine
hydrochloride, 0.04 mg of riboflavin, and 0.25 mg of nicotinic acid.
It occurs as yellowish-white to weak yellowish-orange flakes, granules
or powder, having an odor indicative of the type. It is inactive
in fermenting power.Use
Moist yeast in baking bread, brewing; producing
alcohol by fermentation of sugar, molasses, and cereals; as a source
of vitamins. Dried yeast as a source of vitamins; in baking.
Therapeutic Category
Source of protein and vitamin B complex.
Therapeutic Category (Veterinary)
Dietary source of B vitamins.