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UNITED STATES DEPARTMENT OF AGRICULTURE

Washington, D. C. June 7, 1923

EFFECT OF COMPOSITION ON THE PALATABILITY
OF ICE CREAM.

By Owen E. WitttaMs and Georce R. CampBeELL, Dairy Manufacturing Specialists,
Dairy Division, Bureau of Animal Industry.

CONTENTS.
Page Page.
Factors influencing quality of ice cream....... 1| Experimental work—Continued.
memerinental Work... ..~-..-.------2----+---<- 2 Effect ofsugar on palatability oficecream.. 5
Treatment of mixes and conditions of whip- Effect of milk solids not fat on palatability
RH PTATGU TER TANG = Ae ms So oes 2 Office Cream eee. seein ac dates 5
ethod of comparing the different ice Effect of gelatin on palatability oficecream. 6
BROAN es Soe ae seo aw ee 3 Influence of fat content on quantityeaten.. 7
Effect of fat content on palatability of ice | Best combinations of ice-cream ingredients.... 8
SiETTT SSE 2 ee ee a AS POUT MAT yee awn eee See eg ee EE 8

FACTORS AFFECTING QUALITY OF ICE CREAM.

It has often been said of ice cream that its palatability would be
impaired by making it rich in milk solids and sugar, particularly if
the fat content reached or exceeded 14 per cent. The correctness of
such statements has generally been questioned, although no one has
ever shown in a systematic way the actual rate at which desirability
may be altered by using various percentages of fat, sugar, and other
constituents in the manufacture of ice cream. Manufacturers have
already obtained much information of this character by experiment-

ing with different formulas in their factories and comparing the

results. Many soon found the quality of their product depended on
three main factors: First, the quantity of milk solids the ice cream
contained (composition) ; second, the initial quality of each ingredient;
and third, workmanship.

In an effort to show how important the first factor, composition,
may be to the quality of ice cream, several experiments have been
made to determine what would constitute a relatively good propor-
tion of each of the three principal classes of solids, namely, fat, cane
sugar, and milk solids not fat, in the mix. A similar experiment was
also made with gelatin as an ingredient in ice cream.

40523°—23—Bull. 1161 1

ta eee

2 BULLETIN 1161, U. S. DEPARTMENT OF AGRICULTURE.

EXPERIMENTAL WORK.

TREATMENT OF MIXES AND CONDITIONS OF WHIPPING AND FREEZING. ~

The size of each mix made for these experiments was 25 pounds. .
The treatment given to each set of mixes was always thesame, although |
it was purposely varied on different sets in the same experiment.
Usually one set of mixes was sufficient for at least two days’ sales.
The ice cream was sold to department employees during the noon.
lunch period, between 12 and 12.30.

Some mixes were pasteurized and aged for from 24 to 96 hours.
Others were homogenized and aged for varying periods before freez-_

Fic. 1.—Ice-cream laboratory where experiments are made under conditions similar to thosein commer:
cial manufacture.

ing, while some sets of mixes were frozen a few hours after they were
made up. The temperature at which each set of mixes was aged
also varied.

The whipping and freezing was done in a horizontal 24-quart brine
freezer. The brine temperature varied from 3° F. on some days to
15° F. on other days, with the speed of the freezer kept fairly con-
stant. The ice cream from each mix was hardened in a 3-can cabinet
packed with crushed ice and salt. The amount of inflation (swell)
obtained in the different grades of ice cream ranged from 42 to 93.
per cent.

The ice cream was always hardened in and dispensed from the same
cabinet, so that the temperature and other conditions which might
affect it were practically alike during the time it was offered for sale.

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0 NE rt a ay

COMPOSITION AND PALATABILITY OF ICE CREAM, 3

METHOD OF COMPARING THE DIFFERENT ICE CREAMS.

The difference obtained in the ice creams made in these experiments
was measured by means of a market where about 50 daily purchasers
had an opportunity to choose from three different kinds of ice cream.
Their choice was then taken to represent the degree of desirability of
each kind offered. A nominal flat charge was made for each daily
portion of ice cream. No attempt was made to charge according to
a sliding scale based on the composition of the ice cream, because this
would disclose the difference in quality and defeat the main purpose
of the test.

This is a new method of measuring the desirability of ice cream,
and we believe it has many advantages over the score-card method.

Fic.2.—Three different kinds ofice cream were sold, with an vupportunity to choose the kind preferred
on the following day or days.

Since itis not difficult to obtain the opinion of a much larger number of
people with this method, it is probably more reliable than the score-
card method. Instead of submitting a sample of each different kind
or batch of ice cream to be scored with a score card, we first classified
the experiments relative to the ingredients and limited the number of
ice creams in each experiment to three, so that the major differences
would be in the same general direction in each group of experiments,
Then while the treatment given the three ice creams and the condi-
tions of freezing and hardening were kept the same, the ice creams
were placed on sale for a period of 10 or more days.

The ice cream was sold daily to the purchasers, who did not know
what variation had been made in the composition. Each purchaser
was pee with a weekly coupon ticket, entitling the recipient to
one-half pint each day.

The purchasers were given a sample of each kind of ice cream on

the first day in order to compare the three kinds, and were informed

4 Taw hearse ester Ss Fy

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4 BULLETIN 1161, U. S. DEPARTMENT OF AGRICULTURE.

that on the following day or days they would be given their choice
of the three kinds of ice cream. Sometimes comparison of samples
was made twice a week, but usually only once a week. The pur-
chasers, however, could change from one kind of ice cream to another

at will.
EFFECT OF FAT CONTENT ON PALATABILITY OF ICE CREAM.

In this experiment a comparison was made of three ice-cream

mixes that contained 18, 15, and 12 per cent of fat, while the other |
constituents and methods of manufacture remained the same. |

These three mixes, designated as F, D, and E, respectively, were sold
on each of four consecutive days for three continuous weeks.

The total number of sales for the period covered was 551, and the
number of persons (adults) who purchased was 67. Of this number

¥1Gc.3.—Their second plates in the experiment of“eating at will.’’? Three platefuls were frequently eaten.

316 sales were made to 27 persons, as shown in Table 1, who purchased
the ice cream regularly each week during the 3-week period.

TABLE 1.—Preference for different proportions of fat in we cream by 27 purchasers on
4 days in each of 3 consecutive weeks.

Mix. Times chosen by each purchaser.
HAS percent f46" = 55h sae Pe Wt. 4 UL ALT 210" Ad AZ 12 10 10e Meaieeoeeee
Dip percent fat soa 22 ease eee 0< 0° 4.0) 0154 2 *0350....0790>.0' —-0F Jee
Bed? per cent fat 23-222 ase: See ee eee 0-0: 4.0: 02-610 5 2 2770) — 0 6 25 S25 BO tee ee
Times chosen by each purchaser. Total sales.
Number.) Per cent.
Hl siper-centiat =. \-cce.2 o eee eee eee ie ks Sao (0 Je BPA te a 8 is vr 8 Ne Ba 259 82.0
Dale percent fat. 2.2. fess coe ee eee 0 48 20 10:42) 105-075 e20 FeO 33 10. 4
ih, t2ipercentiat. 2-2... s6.-2 = see ee 10.7 OOF £0) Sie 2 Oe Oe 0 24 7.6
Potale ee sics 2o Set SG Se a ae en ee ee eee ae 316 100.0

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COMPOSITION AND PALATABILITY OF ICE CREAM. 5

The records of the 316 sales in the table show that 82 per cent were
of ice cream containing 18 per cent fat (mix F), and 10.4 er cent
» of the sales were of ice cream containing 15 per cent fat (mix D).
t This left only 7.6 per cent of the sales in which purchasers favored ice
cream containing 12 per cent fat (mix E). The sales not recorded in
the table showed preferences very much the same, 15 per cent being
; in favor of mix FE, 14 per cent in favor of mix D, and 71 per cent in
, favor of mix F. rey

These figures show conclusively that the rich ice cream was pre-
| ferred by a large majority of the purchasers.

EFFECT OF SUGAR ON PALATABILITY OF ICE CREAM.

' To determine the effect of sugar on the desirability of ice cream,
a comparison was made of three ice-cream mixes containing 19, 16,
and 13 per cent of cane sugar. These mixes, designated as G, H, and
I, respectively, contained 14 per cent of fat, and the methods of
“manufacture were practically the same in each case. The ice cream
was sold on 10 different days during three consecutive weeks. The
daily sales are recorded in Table 2.

Taste 2.—Preference for varying proportions of sugar in ice cream by 82 purchasers on 10
different days during 3 consecutive weeks.

Days.
Mix. i Total sales.

. 1 ee a | 9 | 10

: Pat rel ae |

4 [ef ae | Number. | Per cent.
ee MeneCnt SUPAT =. .-222..-.-2---- | 28 | 28 | 27 | 27 | 23 | 26 | 25 | 25 | 29 | 34 272 61.4
Muto per ceut sugar -.-..._--2.....-... | 10; 10} 9) 9413 | 15 | 15 | 15 | 17 | 13 | 126 28. 4
feeee per cent sugar-._.--...-...-...-+-- 5| 5| 8 Pee Se 84 Oy at 45 10.2
Pata a ws... feiss fine seeeeeee eee Pe | G2 AE ao 443 | 100.0

| | |

The total number of sales for the period covered was 443 and
the number of persons who purchased was 82. The records of these
443 sales show that 61.4 per cent of the choices were made in favor
of ice cream containing 19 per cent sugar (mix G); 28.4 per cent
were made in favor of ice cream containing 16 per cent sugar (mix
-H); and 10.2 per cent were in favor of ice cream containing 13 per
cent sugar (mix I). In other words, about 90 per cent of the sales
indicated a preference for ice cream containing 16 per cent or more
of sugar.

EFFECT OF MILK SOLIDS NOT FAT ON PALATABILITY OF ICE CREAM.

In the third experiment a comparison was made of three ice-cream
mixes containing 12, 9, and 6 per cent of milk solids not fat, the
other constituents (fat, 10 per cent; sugar, 14 per cent; and gelatin
0.5 per cent) and the methods of manufacture being practically the
same. These mixes, designated as B, C, and A, respectively, were
sold on 30 different days during a period of six consecutive weeks.
_ The daily sales are recorded in Table 3.

6 BULLETIN 1161, U. S.. DEPARTMENT OF AGRICULTURE.

TaBLE 3.—Preference for different proportions of milk solids not fat in ice cream by 128
purchasers on 30 days in 6 consecutive weeks.

Mix. Total sales.

Number. . | Per cent.

1B; 12 -per'cent milk: solids mot:fatss2a. See ecns select aoe ee ee eee ee eee 665 56. 1
C;-9 per cent. milk'solids not fat: -2eosseeoecee oases: Soe eee eee ae 305 25.7
A, 6 per cent milk solids not fat...... Se ee ae enn ONAN a, nen ee 215 18.2

Totale 5.2 3 Std ease qesde Sonat goo Soe e- os eae SAE eae ye ee ees Sears 1,185 100.0

The records of these 1,185 sales show that 56.1 per cent of the
choices were made in favor of the ice cream containing the greatest
quantity (12 per cent) of milk solids not fat (mix B); 25.7 per cent
were in favor of the ice cream containing 9 per cent milk solids not
fat (mix C); and 18.2 per cent were in favor of ice cream containing
6 per cent milk solids not fat (mix A). This means that over 80 per
cent of the sales indicated a preference for ice cream containing at
least 50 per cent more milk solids not fat than is often found in:
commercial ice cream, i. e., a preference for 9 per cent or more,
instead of about 6 per cent, in ice cream testing 10 per cent fat.

About two-thirds of the total sales in this test were to persons who
ate the ice cream for prolonged periods. Thus, 11 persons purchased
for . consecutive weeks, 12 for 4 weeks, 9 for 5 weeks, and 7 for 6
weeks,

The percentages of preference for the different amounts of milk
solids not fat shown by these 39 different persons are given in Table 4.

There was not much difference in the results as compared with
Table 3.

TaBLE 4.—Preference for different proportions of milk solids not fat in ice cream by 39
persons purchasing it during periods of 3 to 6 consecutive weeks.

Mix. Total sales.

Number. | Per cent.
'B; 12 per cent. milk:solidsmotdateesessccs cee = eee eee 438 53.3
C; 9: per: cent-milk solids mot fats: es ose te. oe eee eee eee ae 226 27.5
AS Oper cent milk solidSmotriat: se sone shee nas se eee nee eae oe eee eS eee 158 19. 2

"Bota one he boca cten cee ee ree = aoe eee ee oe eee 822 100. 0

EFFECT OF GELATIN ON PALATABILITY OF ICE CREAM.

In the fourth experiment a comparison was made of three ice-cream
mixes containing 0, 0.5, and 1 per cent of medium-grade gelatin, with
the other constituents and methods of manufacture kept the same.
These mixtures were designated as K, M, and L, respectively. They
were prepared on nine different occasions, and each mix was pas-
teurized and homogenized. The mixes were then held for varying
periods before freezing, ranging from one to five days. The number
of sales made on 10 days during the three consecutive weeks was

623, these sales being made to 66 persons. The results are given in
Table 5.

ete

COMPOSITION AND PALATABILITY OF ICE CREAM, 7

Taste 5.—Preference for varying proportions of gelatin in ice cream by 66 persons dur-
ing 10 days in 3 consecutive weeks.

Mix. | Total sales.

Number.| Per cent.
394 5

DPBMETICOMUIC OL ALE eee ee ee Nan ee comin Sacelgesceceaced atinebes ace 63. 2
OS Tn 7 peo RR Spee a ga 2 NN LE 86 13.8
ER SAE ee ee ea ee ee 143 23.0

epee ets 2 RIK. Saeed Pe eee ees ena d ib Se Hoc mds soe saa 623 100.0

Table 5 shows that in 394, or 63.2 per cent, of the sales the pur-
chasers asked for the ice cream that contained 1 per cent of gelatin
(mix L) ; in 143 sales, or 23 per cent, they asked for the ice cream that
contained no gelatin (mix K); and in 86, or 13.8 per cent, they asked
for the ice cream that contained 0.5 per cent of gelatin (mix M).
This shows that when preference was given to ice cream made with-
out gelatin or with gelatin, the ratio was a little less than 3 to 1 in
favor of the product with gelatin.

INFLUENCE OF FAT CONTENT ON QUANTITY EATEN.

The fat content of ice cream does not seem to have a great effect
on the quantity of ice cream a person will eat, except, perhaps, when
itis very rich. A test made with two ordinary grades of ice cream,
one containing 10 per cent and the other 15 per cent fat, showed that
the average adult person consumed 341 grams (1.2 pints) of the
10 per cent cream and 317 grams (1.12 pints) of the 15 per cent cream
when given all he would eat.

The test was made by serving groups of from five to seven persons
from a weighed can of ice cream. After they had eaten all they
wanted, the can was reweighed, and the total amount consumed was
divided by the number of persons eating. This was done at 12 dif-
ferent times, 6 times with ice cream containing 10 per cent fat and
6 times with ice cream containing 15 per cent fat. The time of this
experiment was in March and April, 1921.

TABLE 6.—Quantity of ice cream of varying fat content consumed on 12 different days by
groups of 5 to 7 persons eating at will.

Quantity consumed. Quantity consumed.
ee aaier eT Loar Sokal aul ie Number
est No. to) est No. of
Average Average
Persons. || Total. per PEFSODS~ | 'Potal: per
person. person.
Ice cream contain- Ice cream contain-
ing 10per cent fat: Grams. | Grams.1 ing 15per cent fat: Grams.! | Grams.
ieee Ante te 7 m 300 er ae 7 2,177 311
Deen Rincon setae & cf 1, 981 283 oe re ee Seog 7 1, 848 264
Seperate sh etoae tf 2, 520 360 Qe livecstezere 7 1, 946 278
es eee 5 2, 390 478 DO freee os 6 2, 226 371
Detar ciscves ste. 5 2, 380 476 i ee ee eee 5 1, 860 372
Goren cece aco e 7 1, 596 228 i oar Aer ae 5 1,670 334
Total and Total and
average. ... 38 12, 967 341 average. ... 37 11, 727 317

1 One pint ofice cream, weighing 5 pounds per gallon, equals 283 grams.

8 BULLETIN 1161, U. S. DEPARTMENT OF AGRICULTURE.

BEST COMBINATIONS OF ICE-CREAM INGREDIENTS.

A question frequently asked is, What combination will produce
the best quality of ice cream? It has been shown that a preferen
is usually given to the ice creams richest in fat, sugar, and mil
solids not fat, but no attempt was made in our experiments to ascer-
tain the optimum combination of all these ingredients to produce
the best product. To do this would require a very large number of
tests. The results, however, might prove beneficial in establishing
one type of commercial ice cream instead of the two types we now
have, 1. e., one rich in fat and the other rich in milk solids not fat.
This is a matter that must be left for further consideration.

SUMMARY.

The effect of the composition of ice cream on its palatability was_
tested by selling ice cream made in different ways to the same per-
sons from day to day, serving it in such a manner that the buyers
would show their preference, and noting the kinds preferred and the
extent to which they were preferred.

Experiments with varying proportions of fat, sugar, milk solids |
not fat, and gelatin in ice cream show that there is a decided pref-
erence by consumers for the richest, sweetest, and firmest products.
The following figures express the results obtained:

Butterfat.—The effect of fat on the palatability of ice cream is indicated by prefer-
ence in 82, 10.4, and 7.6 per cent of the cases in favor of ice cream containing 18, 15,
and 12 per cent of fat, respectively.

Sugar.—The effect of sugar on the palatability of ice cream is indicated by prefer-
ence in 61.4, 28.4, and 10.2 per cent of the cases in favor of ice cream containing
19, 16, and 13 per cent sugar, respectively.

Milk solids not fat.—The effect of milk solids not fat on the palatability of ice cream
containing 10 per cent of fat is indicated by preference in 55.6, 25, and 18.6 per cent
of the cases in favor of ice cream containing 12, 9, and 6 per cent of milk solids not —
fat, respectively.

Gelatin.—The effect of gelatin on the palatability of ice cream containing 14 per —
cent fat is indicated by preference in 63.2, 13.8, and 23 per cent of the cases in favor
of ice cream containing 1, 0.5, and 0 per cent of gelatin, respectively.

Experiments on the influence of fat content on the acceptability
of ice cream shows that the amount of ice cream eaten containing 10
per cent and of that containing 15 per cent of fat averages practically
the same.

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