The cooperators in lard investigations at Iowa State College Experi-
ment Station determined the amount of fat absorbed by doughnuts and
the changes in the fats caused by cooking doughnuts in each fat, the period
of heating each fat being kept constant at 10j4 hours. These studies were
continued over a period of 3 years, the same operator, Jensen, making and
frying all the doughnuts, so that a highly specialized technic was developed.
Standardized conditions of mixing, which included incubation of all mate-
rials at a definite temperature before mixing and mixing with a Kitchen-
Aid, were maintained. Six mixes or batches of dough were required for
the doughnuts fried in each fat. The term ''firsts" was applied to dough-
nuts cut after the first rolling of the dough. The scraps were then collected
and rerolled. The doughnuts from this lot were designated as ''rerolls."
Again the scraps were collected and rerolled, the doughnuts from this lot
designated as ''re-rerolls." The following results are from tests during the
third year only.
A total of 12 fats were used, of which 2 were open-kettle rendered
lards, 5 were prime-steam rendered lards, 1 hydrogenated lard, 1 hydro-
genated cottonseed oil, and 1 corn oil.
TEMPERATURE OF INGREDIENTS WHEN MIXED 557
Number of "firsts" cooked in each fat 12 dozen
Number of "rerolls" cooked in each fat 6 dozen
Number of "re-rerolls" cooked in each fat 2>^ dozen
Average fat absorption from all fats for "firsts" 28.6 per cent
Average fat absorption from all fats for "rerolls" 22.3 per cent
Average fat absorption from all fats for "re-reroUs" 18.5 per cent
The analysis of variance indicated exceedingly high uniformity among
rollings, i.e., "firsts" always absorbed the most fat, etc., but great variation
among different mixes or batches so that the variation from mix to mix
was used as the experimental error. The variation of amount of fat absorbed
by the different fats was also highly significant. Further analysis of the
data showed a significant negative correlation between the smoking point of
the fat and the amount of fat absorbed by the doughnuts, which indicated
that the lower the smoking point the greater the amount of fat absorbed
by the doughnuts. The iodine value, the percentage of free fatty acids,
and the refractive index had no effect on the amount of fat absorbed.
However, a highly significant negative correlation was found between the
free fatty acids content and the smoking point of the fat which agrees with
former findings of Blunt and Feeney and Morgan and Cozens.
Denton and co-workers have also published results for fat absorption in
doughnuts and other foods. Their conclusions are similar to those of the
investigators mentioned above and to the following class results, so will
not be given in detail.
Factors Affecting the Amount of Fat Absorbed During Cooking
and the Texture of the Doughnuts
Page 443
Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
A modernized reading is not available for this page yet. You are seeing the original text.
The cooperators in lard investigations at Iowa State College Experi-
ment Station determined the amount of fat absorbed by doughnuts and
the changes in the fats caused by cooking doughnuts in each fat, the period
of heating each fat being kept constant at 10j4 hours. These studies were
continued over a period of 3 years, the same operator, Jensen, making and
frying all the doughnuts, so that a highly specialized technic was developed.
Standardized conditions of mixing, which included incubation of all mate-
rials at a definite temperature before mixing and mixing with a Kitchen-
Aid, were maintained. Six mixes or batches of dough were required for
the doughnuts fried in each fat. The term ''firsts" was applied to dough-
nuts cut after the first rolling of the dough. The scraps were then collected
and rerolled. The doughnuts from this lot were designated as ''rerolls."
Again the scraps were collected and rerolled, the doughnuts from this lot
designated as ''re-rerolls." The following results are from tests during the
third year only.
A total of 12 fats were used, of which 2 were open-kettle rendered
lards, 5 were prime-steam rendered lards, 1 hydrogenated lard, 1 hydro-
genated cottonseed oil, and 1 corn oil.
TEMPERATURE OF INGREDIENTS WHEN MIXED 557
Number of "firsts" cooked in each fat 12 dozen
Number of "rerolls" cooked in each fat 6 dozen
Number of "re-rerolls" cooked in each fat 2>^ dozen
Average fat absorption from all fats for "firsts" 28.6 per cent
Average fat absorption from all fats for "rerolls" 22.3 per cent
Average fat absorption from all fats for "re-reroUs" 18.5 per cent
The analysis of variance indicated exceedingly high uniformity among
rollings, i.e., "firsts" always absorbed the most fat, etc., but great variation
among different mixes or batches so that the variation from mix to mix
was used as the experimental error. The variation of amount of fat absorbed
by the different fats was also highly significant. Further analysis of the
data showed a significant negative correlation between the smoking point of
the fat and the amount of fat absorbed by the doughnuts, which indicated
that the lower the smoking point the greater the amount of fat absorbed
by the doughnuts. The iodine value, the percentage of free fatty acids,
and the refractive index had no effect on the amount of fat absorbed.
However, a highly significant negative correlation was found between the
free fatty acids content and the smoking point of the fat which agrees with
former findings of Blunt and Feeney and Morgan and Cozens.
Denton and co-workers have also published results for fat absorption in
doughnuts and other foods. Their conclusions are similar to those of the
investigators mentioned above and to the following class results, so will
not be given in detail.
Factors Affecting the Amount of Fat Absorbed During Cooking
and the Texture of the Doughnuts