Yeast as a Human Food
Cecilia Schuck.
Professor of Foods and Nutrition
Purdue University
Lafayette, Indiana
Research leading to the development of food yeasts and an understanding of their nutritive value had its origin in the brewing industry.
Nutritional values of products depending on fermentation processes
are increased by any yeast remaining in the product. The Egyptians
who sold unclarified beer to the "unfortunate poor" and the clear
sparkling product to the wealthy were really, from a nutritional standpoint, favoring the former and short-changing the latter.
The slow fermentation process formerly used in bread-making imparted little nutritive value to the loaf because of the small amount of
yeast used. With the larger quantity of yeast now required for the
more rapid process, the nutritive value of the bread is increased. And
it may be further increased without detriment to the quality of the loaf
by the addition of from two to three percent of unfermentable food yeast.
No doubt many of you remember when compressed yeast was rather
commonly used as a food supplement. This practice may still be in vogue.
Some of us rebelled at this method of dietary improvement because of
the unpleasant flavor of the yeast. In addition, fermentation sometimes
produced undesirable effects in the digestive tract. More recently it has
been shown that because of poor absorption, the thiamine and riboflavin
of live yeast cells are largely unavailable to the body.fij (2)* Today
the yeast most commonly used for human food is a dry, mild-flavored
unfermentable product, which is sometimes designated "food yeast."
Marked impetus was given to the production and use of food yeasts
during the second World War. Special dried food yeasts were cultivated by both the British and Germans to provide proteins and B-vita-
mins to the wartime dietary. The German production is reported to
have reached 200,000,000 pounds during the war period.
In this country the use of yeast as a human food was likewise stressed
in World War II. On January 5, 1943, the Food and Nutrition Board
of the National Research Council passed this resolution: "Resolved
that dry yeast be considered a natural food substance and that it be
* Italicized   figure>   in   parentheses   refer   to   entries   in   the   bibliography,
page 108.
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