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L16I— O-I096
Dextrose in Commercial
Ice -Cream Manufacture
By W. J. CORBETT and P. H. TRACY
Bulletin 452
CONTENTS
PACE
REVIEW OF LITERATURE 347
PART I: ADAPTABILITY OF DEXTROSE FOR USE IN
COMMERCIAL ICE CREAM 348
Comparison of Qualities of Part-Dextrose and All-Sucrose Ice Creams 348
Effect of Time of Adding Dextrose to Mix 357
Comparison of Different Types of Dextrose 358
Use of Dextrose in Counter Freezer Mix 358
Use of Dextrose in Mix When Frozen on Vogt Continuous Freezer. ... 358
PART II: EFFECT OF DEXTROSE ON CERTAIN PHYSICAL
AND CHEMICAL PROPERTIES OF THE ICE-CREAM MIX 360
Color 360
Viscosity 363
Acidity 364
Curd Tension 367
Protein Stability 368
PART III: CONSUMER PREFERENCE STUDIES ON QUALITIES
OF PART-DEXTROSE AND ALL-SUCROSE ICE CREAMS 368
Ice Creams Judged for Body, Flavor and Sweetness 369
When Hydrous Dextrose Was Given a Sweetening Value of 70. ... 369
When Hydrous Dextrose Was Given a Sweetening Value of 100. . . 371
When Hydrous Dextrose Was Given a Sweetening Value of 83.5. . . 372
When One-Fourth of the Sucrose Was Replaced With Anhydrous Dex-
trose Pound for Pound 373
Comparison of Ice Creams for Their Refreshing Qualities 373
SUMMARY 375
CONCLUSIONS 378
LITERATURE CITED 378
APPENDIX 379
ACKNOWLEDGMENT
Acknowledgment is made of the cooperation of the Corn Products Refining Com-
pany of Argo, Illinois, in the promotion of the studies reported in this bulletin.
Urbana, Illinois March, 1939
Publications in the Bulletin series report the results of experiments
made by or sponsored by the Experiment Station
Dextrose in Commercial Ice-Cream
Manufacture
By W. J. CORBETT and P. H. TRACY*
THE BROWN COLOR and bitter flavor of the corn sugar
placed on the market during the prewar period limited its use
somewhat in the food industries. Since that time, however,
manufacturing methods have been so improved that the sugar pro-
duced from corn grain today is far superior to that previously manu-
factured, being of a snow-white color and of a pleasing flavor. A
description of the modern method of manufacturing dextrose is given
in the Appendix on page 379.
Most of the investigations heretofore reported on dextrose were
made previous to the development of more improved methods of
manufacture. The experiments described in this bulletin were made
to study the merits of dextrose, as it is now refined, in the manufacture
of ice cream.
REVIEW OF LITERATURE
In 1918 Ayers, Williams, and Johnson2* found that a portion of the
sucrose in ice cream could be replaced with some grades of dextrose,
but not with other grades which imparted a yellow color and a bitter
flavor. They reported a sweetness of 80 for dextrose, considering the
sweetening value of sucrose to be 100. The same year Frandsen,
Rovner, and Luithly9* found that 50 percent of the cane sugar used in
ice cream could be satisfactorily replaced with dextrose. When the
entire amount of cane sugar was replaced with dextrose, the ice cream
lacked sweetness and had an unpalatable flavor.
Combs4* reported in 1926 that ice cream containing dextrose must
be frozen, held, and served at lower temperatures than all-sucrose ice
cream. Tracy and McCown,14* and Combs and Bele5* also found a
slower heat transmission in the hardening room for dextrose ice cream.
Martin12* reported in 1927 that dextrose mixes required a longer
period of refrigeration in the freezer and caused delayed whipping.
Both Combs and Erb8* found that dextrose had little or no effect in
preventing or delaying the occurrence of sandiness, whereas Anthony
JW. J. CORBETT, First Assistant in Dairy Research, and P. H. TRACY,
Chief in Dairy Manufactures.
*Superior figures with asterisk refer to literature citations, pages 378-379.
347
348 BULLETIN No. 452 [March,
and Lund1* found that dextrose delayed the occurrence of sandiness
to a marked degree, and that lactose was much more soluble in a
dextrose-sucrose mixture than in combination with sucrose alone.
Combs also suggested that dextrose, because of its greater bulk in
relation to its sweetness, could be substituted for a part of the serum
solids. From this standpoint, dextrose has found favor with the ice-
cream industry, for it made it possible to build up the solids in
low-total-solids mixes at little or no additional cost.
Mack11* in 1935 recommended the replacement of part of the
sucrose with dextrose in high- fat and high-total-solids ice creams, to
prevent the ice creams from having a crumbly texture and to improve
the melting qualities.
PART I: ADAPTABILITY OF DEXTROSE FOR USE IN
COMMERCIAL ICE CREAM
To test the adaptability of dextrose for use in commercial ice
cream, all-sucrose ice creams and part-dextrose ice creams were com-
pared for sweetness, body and flavor, whipping ability, freezing time,
melt down, sandiness, hardness, and dipping losses. The effects of the
time of adding dextrose to the mix, of different types of dextrose
sugars, and of the use of dextrose in the counter freezer mix and in
ice cream frozen on the Vogt continuous freezer were also studied.
Unless otherwise stated, the data presented in this bulletin were
obtained in tests of mixes in which one- fourth of the sucrose had
been replaced with dextrose. These mixes are referred to as dextrose
mixes.
For the tests in Part I the mixes were prepared in lots of various
size from 40-percent cream, skimmilk, skimmilk powder (or sweetened
condensed skim, or condensed skim, or condensed whole milk), gelatin,
powdered egg yolk, and sugar. Mixes were pasteurized and processed
at 150° F. and homogenized at 2,500 pounds pressure.
COMPARISON OF QUALITIES OF PART-DEXTROSE AND
ALL-SUCROSE ICE CREAMS
Sweetening Value
At the beginning of this study the authors determined (by organo-
leptic tests of water solutions of the various sugars) that on a basis
of a sweetening value of 100 for cane sugar hydrous dextrose had a
sweetening value of 65 to 70 and anhydrous dextrose had a sweetening
value of 70 to 75. However, thru tests described here and thru more
1939] DEXTROSE IN COMMERCIAL ICE CREAM 349
extensive tests described in Part III, it was found that when used in
conjunction with sucrose in ice cream dextrose had a sweetening value
considerably higher than it had in a water solution.
The authors wished to use consumer tests to determine the sweet-
ening value of dextrose in ice cream, but before this could be done,
it was necessary to test the average consumer's ability to detect differ-
ences in sweetness. In order to do this, 123 persons were served ice
creams made from 14, 15, and 16 percent cane-sugar mixes and were
asked to select the sweetest ice cream. The results were as follows:
Sugar content of mix Times selected as sweetest
14 percent 13
15 percent 28
1 6 percent 60
22 consumers could detect no difference
After finding that a large percentage of consumers were able to
detect differences in the sweetness of ice cream varying 1 to 2 percent
in sugar content, the consumer test was then used to determine the
sweetening value of dextrose in ice cream. The all-sucrose-sweetened
and part-dextrose-sweetened ice-cream samples used for these tests
were prepared from the same milk products and were processed and
frozen at the same time. Only two ice creams were compared at the
same time, and these were served on different-shaped paper plates so
they could be distinguished easily. Each consumer was given a form
sheet on which his preference could be indicated.
The preferences expressed by 1,244 consumers who were served
the above ice creams and were asked to compare them for sweetness
are given in Table 1. From the first group of 611 consumers it was
evident that a sweetening value of 70 for dextrose (the sweetening
value of sucrose being considered 100) was too low, because the ice
cream in which one- fourth of the sucrose was replaced with 1.43
pounds of dextrose per pound of sucrose omitted, was considered
sweeter than the all-sucrose ice cream by a large number of consumers.
Further tests showed that hydrous dextrose was not sweet enough
to replace sucrose pound for pound, making a sweetening value of 100
for this dextrose too high.
When, however, hydrous dextrose was given a sweetening value of
83 and substituted for sucrose at the rate of 1.2 pounds to 1 pound of
sucrose, the resulting sweetness was comparable to that of the all-
sucrose ice cream.
It was also found that sucrose could be replaced with anhydrous
dextrose, pound for pound, without a noticeable loss of sweetness in
the ice cream.
350
BULLETIN No. 452
[March,
TABLE 1. — CONSUMER COMPARISON OF SWEETNESS OF ALL-SUCROSE AND DEXTROSE
ICE CREAMS*
Pounds of dextrose used
to replace one pound
of sucrose
Total
number of
consumers1"
Number of consumers expressing opinion
indicated
Dextrose ice
cream sweeter
Sucrose ice
cream sweeter
No differ-
ence
Hydrous dextrose ice creams
1.43...
611
308
186
117
1.33
57
17
26
14
1.20
167
56
64
47
1.00
284
79
153
52
Anhydrous dextrose ice cream
1.00
125
46
52
27
•Unless otherwise stated, "dextrose ice cream" refers to ice cream in which one-fourth of the
sucrose was replaced with dextrose.
bThe consumers included two home-bureau clubs, a faculty women's club, a business men's
club, a ladies' social club, dairy manufactures groups, and advanced classes in dairy manufactures
and home economics, as well as faculty and office employees in the College of Agriculture.
Whipping Ability
The whipping ability of fifteen all-sucrose mixes varying in
sugar content from 14 to 18 percent was compared with the whipping
ability of the same number of mixes in which one- fourth of the
sucrose was replaced with dextrose. The rate at which the dextrose
was added varied from 1 to 1.43 pounds for each pound of sucrose
replaced. The mixes were aged 24 hours and frozen on a 40-quart
direct-expansion freezer. Minute overrun and temperature readings
were taken. All the mixes were frozen to the same consistency before
the refrigeration was turned off.
In 40 percent of the tests a longer time was required to remove
the heat from the sucrose than from the dextrose mixes (Table 2).
In 53.3 percent of the tests it took longer to remove the heat from the
dextrose mixes, and in 6.7 percent there was no difference.
In 80 percent of the tests more time was required for the sucrose
mixes to whip to 100 percent overrun, and in 20 percent the dextrose
mixes whipped slower. However, the differences were so slight that
they were considered of no practical significance.
Minimum and Drawing Temperatures
Because it is a monosaccharid, dextrose depresses the freezing
point of solutions to a greater extent than does sucrose. It naturally
follows, therefore, that ice cream containing dextrose will reach a
lower temperature during the freezing process than will that con-
1939]
DEXTROSE IN COMMERCIAL ICE CREAM
351
TABLE 2. — WHIPPING ABILITY AND MINIMUM AND DRAWING TEMPERATURES OF
ALL-SUCROSE AND DEXTROSE ICE CREAM MIXES OF
VARYING SUGAR CONTENT
Sugar content of mix
Time to remove
heat from mix
Time to whip
to 100%
overrunb
Minimum
temperature
Drawing
temperature
Mix A
Mix B
Sucrose
Sucrose
Dextrose
Mix A
MixB
Mix A
MixB
Mix A
MixB
Mix A
MixB
perct.
perct.
perct.
°F.
°F.
*F.
°F.
14
10.5
3.5*
2' 50*
2' 53*
3' 10*
3' 7"
23.8
22.8
24.1
22.9
14
10.5
3.5«
2' 45'
2' 55*
3' 15"
3' 5"
24.8
23.5
25.2
24.4
14
10.5
3.5«
2' 50*
2' 50*
4' 00*
3' 50*
24.55
23.85
25.0
24.3
14
10.5
4.65
2' 50*
3' 15*
4' 10*
3' 45*
24.9
23.8
25.6
24.6
14
10.5
4.20
2' 50*
2' 55*
3' 40*
3' 35"
24.5
23.2
25.0
23.8
14
10.5
4.0
2' 45*
2' 53*
3' 15"
3' 7"
25.6
24.0
25.8
24.2
14
10.5
5.0
2' 43*
2' 38*
4' 12"
3' 52"
24.7
23.2
25.1
23.6
14.5
10.85
5.7
2' 47*
2' 52*
3' 43"
3' 8"
24.1
22.9
24.7
23.3
IS
11.25
4.5
2' 55"
2' 45*
4' 25"
4' 5*
24.4
22.7
25.0
23.3
15
11.25
4.5
2' 55"
2' 45*
4' 25*
6' 15"
24.4
23.0
25.0
24.0
15
11.25
5.6
2' 43*
2' 38*
4' 12"
3' 52"
24.7
23.2
25.1
23.6
15
11.25
3.75»
3' 10*
3' 3*
2' 50*
2' 57"
23.9
23.0
24.3
23.1
15
11.25
4.5
2' 55*
2' 52"
2' 20"
2' 8"
23.95
23.2
24.1
23.25
16
12.0
4.0«
2' 50*
2' 55"
3' 10"
3' 35*
22.9
22.1
23.3
22.5
18
13.5
4.5»
2' 50*
2' 53*
3 40*
3' 37*
22.1
21.1
22.7
21.6
Average
2' 53*
2' 55*
3' 48"
3' 42"
24.2
23.1
24.5
23.5
•Anhydrous dextrose.
bFrom time refrigeration was shut off until ice cream reached 100 percent overrun.
taining all-sucrose sweetening. The average difference between the
minimum temperature of the dextrose and that of the sucrose mixes
was 1.1 degrees and the average difference between the drawing tem-
peratures was 1 degree (Table 2). The dextrose mixes all registered
lower temperatures than did the sucrose mixes.
Body and Flavor Scores
All the ice creams were scored and criticized for body and flavor
24 or 48 hours after they were frozen. The score card used in the
national collegiate judging contest was used in this study. When
matched samples were compared (Table 3), the all-sucrose and the
dextrose ice creams received the same body score in 42.8 percent of
the tests. Each was adjudged superior in 28.6 percent of the tests.
The most often expressed criticism of the body of the dextrose ice
cream was that it melted quicker in the mouth than did the sucrose.
The dextrose ice cream scored below the sucrose ice cream in
flavor only once, except in those experiments in which sucrose was
replaced with hydrous dextrose pound for pound. Then the resulting
ice cream was scored down because it was not so sweet.
352 BULLETIN No. 452
TABLE 3. — Bony AND FLAVOR SCORES OF ALL-SUCROSE
AND DEXTROSE ICE CREAMS
[March,
Composition of mix
Body
score*
Flavor
scoreb
Fat
Sucrose
Dextrose
Anhydrous dextrose ice creams
perct.
12
perct.
14
10.5
perct.
0
3.5
23.5
23.5
44
44
12
16
12
0
4.0
23.75
23.75
44
44
12
18
13.5
0
4.5
24
24
44
44
Hydrous dextrose ice creams
12
14
11.4
0
4.0
22.5
23
43.5
43.5
12
14
10.5
0
5.0
23.5
22.5
44
43.5
12
14
10.5
0
3.5
23.5
23.75
43.5
43
12
14
10.5
0
3.5
23.75
23.5
42
41.5
12
14
10.5
0
4.65
23.5
23
43.5
43.5
12
14
10.5
0
4.25
23
23
44
44
12
14
10.5
0
4.25
22.5
22.5
42.5
42.5
12
15
11.25
0
4.5
22.5
23
44
44
12
15
11.25
0
4.5
23.5
23
44
44
14
14.5
10.85
0
5.7
23.75
24.25
43.5
43.5
16
15
11.2
0
5.6
25
25
45
45
•Perfect score is 25.
bPerfect score is 50, tho 46 is high.
Melt Down
The proper rapidity of melt down is a rather controversial issue
among ice-cream manufacturers. A certain degree of ability to "stand
up" is necessary for commercial ice cream that is subjected to careless
handling while being served or marketed. Excessive resistance to
melting, however, is neither necessary nor desirable, as it detracts
from both the eye appeal and the palatability of the ice cream.
Melting tests were made on duplicate pint samples of frozen ice
1939] DEXTROSE IN COMMERCIAL ICE CREAM 353
cream either 24 or 48 hours after freezing. The ice cream was
hardened in pint Sealrights, which were taken from the hardening
room 3 hours before the tests were to be run and the sides and top of
the cartons removed. A wire was run thru the middle of each sample
to facilitate handling, and then the samples were put back into the
hardening room for 3 hours. At the beginning of the tests the samples
were placed on glass tumblers inverted on 10-inch .pie tins. The
tumblers and pie tins had been previously weighed. At regular inter-
vals the ice-cream samples were lifted off the tumblers by means of
the wires run thru the middle, and the amount of melted ice cream
from each sample was weighed and the percentage loss calculated.
The average percentage loss in duplicate samples is given in Table
4. It was found that there was an average of 2 to 3 percent greater
melt down with the dextrose ice creams than with the all-sucrose ice
creams at the various intervals.
Assuming that a desirable melt down is one which is smooth,
creamy, even, and free from masses of foamy mix, the dextrose mixes
gave as desirable a melt down as did the sucrose mixes.
Sandiness
Sandiness in ice cream is most troublesome during the winter
months when the supplies in dealers' cabinets move slowly. This
defect can be avoided for the most part by keeping the concentration
of lactose below a certain level. Since dextrose causes a marked differ-
ence in crystal behavior in candy, as is generally known, it was desired
to study the effect of dextrose on the occurrence of sandiness in ice
cream.
For this experiment mixes containing 12 percent fat and 12 per-
cent serum solids were used. The sugar content varied from 14 to 18
percent. For the most part the results were slightly in favor of the
dextrose ice creams (Table 5). That is, when differences were detect-
able, slightly more sandiness developed in the all-sucrose ice cream
than in the dextrose. All the positive organoleptic tests were checked
with the microscope to substantiate the results.
Dipping Losses
Dipping losses are one of the problems confronting retailers of
bulk ice cream. Since the temperature at which the ice cream is
dipped has been found to be closely related to dipping losses, it is
important that the dipping temperature be lowered if the freezing
point of the mix has been lowered. Bierman3* at the University of
354 BULLETIN No. 452 [March,
TABLE 4. — MELT DOWN OF SUCROSE AND DEXTROSE ICE CREAMS
Composition of mix
Amount melted at intervals indicated
Fat
Sucrose
Dextrose
30'
60'
90'
120'
ISO'
Anhydrous dextrose ice creams
perct.
perct.
perct.
perct.
Perct
perct.
perct.
Perct.
12
14
0
0
11
34
54
10.5
3.5
0
17
25
52
12
16
0
0
12
33
53
12
4.0
0
10
38
55
12
18
0
0
17
35
55
13.5
4.5
0
21
42
62
Hydrous dextrose ice creams
12
14
0
0
14
41
59
11
4.0
2
14
44
59
12
14
0
5
38
63
80
10.5
5.0
13
52
72
85
12
14
0
2
7
32
50
10.5
3.5
0
7
36
54
12
14
0
0
7
35
52
10.5
3.5
0
8
35
56
12
14
0
0
0
21
37
51
10.5
4.65
0
0
21
36
46
12
14
0
0
20
48
72
83
10.5
4.25
0
26
55
78
85
12
15
0
12
48
77
89
11.25
4.5
8
44
74
88
12
15
0
0
15
41
64
78
11.25
4.5
0
16
40
64
76
14
14.5
0
0
7
13
18
32
10.85
5.7
0
7 .
21
34
59
16
15
0
7
40
64
80
11.2
5.6
11
46
67
83
Maryland found that a dipping temperature of 8° F. gave the best
results for a mix containing 12 percent fat, 10.5 percent serum solids,
15 percent sugar (all sucrose), and .35 percent gelatin. He recom-
mended that the dipping temperature be lowered 1 degree for each
percent of increase in sugar because of the greater softness of ice
cream of higher sugar content.
Since dextrose depresses the freezing point of mixes to a greater
extent than sucrose does, it naturally follows that somewhat lower
dipping temperatures should be maintained for dextrose ice creams
than for all-sucrose ice creams.
Attempts were made to determine the dipping losses of all-sucrose
1939]
DEXTROSE IN COMMERCIAL ICE CREAM
355
TABLE 5. — RELATION OF PRESENCE OF DEXTROSE TO DEVELOPMENT OF SANDINESS
IN ICE CREAM
(Mixes contained 12 percent fat and 12 percent serum solids.)
Sugar content of mix
Intensity of sandiness under conditions indicated*
Sucrose
Dextrose
-15° toO" F. storage
0° to 10° F. storage
17 days
30 days
17 days
7 days
30 days
perct.
14
10.5
perct.
0
3.5
5
6
No difference
detectable
5
4
6
5
No difference
detectable
16
12
0
4.0
3
2
No difference
detectable
3
2
4
2
No difference
detectable
18
13.5
0
4.5
4
1
No difference
detectable
6
1
3
1
No difference
detectable
•The intensity of sandiness is shown by numbers, 1 being the least sandy and 6 the most sandy.
and dextrose ice creams dipped at different temperatures (Table 6).
Five-gallon ice-cream cans were filled directly at the freezer with ice
cream containing 100 percent overrun. After the ice cream had suffi-
cient time to harden in the hardening room, it was placed in electric
cabinets where the temperatures were carefully regulated. After the
ice cream had been given sufficient time to come to the same tempera-
ture as the cabinet, it was dipped into quart packages and the yield
calculated. The figures given in Table 6 are averages of duplicate or
triplicate tests.
When the sucrose ice cream was dipped at the same temperature
as the dextrose ice cream (considering only matched pairs dipped at
TABLE 6. — DIPPING LOSSES OF SUCROSE AND DEXTROSE ICE CREAMS"
Composition of mix
Losses when dipping was done at:
Fat
Sucrose
Dextrose
0°F.
4°F.
8°F.
12° F.
perct.
12
perct.
15
11.25
perct.
0
5.3
perct.
perct.
25
32.5
perct.
27.5
35
perct.
12
14
10.25
0
3.5
28.75
30
30
31.25
12
14
10.5
0
4.25
3S"
37.5
14
15
11.25
0
5.3
30
27.5
31.25
31.25
32.5
35
32.5
35
14
17.5
13
0
4.5
3l'.2S
35
•Ice creams in 5-gallon cans were dipped into quart paper containers.
356 BULLETIN No. 452 [March,
the same temperature), the average dipping loss for the sucrose was
29.7 percent and for the dextrose 32.2 percent.
Percentage dipping losses at
temperatures indicated
0° F. 4° F. 8° F. 12° F. Average
Sucrose ice cream 29.37 28.75 30.0 32.5 29.7
Dextrose ice cream 28.75 31.66 35.0 35.0 32.2
However, when the dipping temperature of the dextrose ice cream
was 4 degrees lower than that of the sucrose ice cream, the average
dipping losses of the two ice creams were comparable. Averages
calculated in this manner show a dipping loss of 32.3 percent for the
all-sucrose and 31.8 percent for the dextrose ice cream.
Percentage dipping losses at
temperatures indicated
0° F. 4° F. 8° F. 12° F. Average
Sucrose ice cream 29.37 31.75 30.0 32.5 32.3
Dextrose ice cream 30.99 36.66 35.0 35.0 31.8
Hardness
It is generally thought that dextrose produces an ice cream which
breaks faster on the tongue and is less chewy than all-sucrose ice
cream. The dextrose ice cream is also softer because of the greater
proportion of unfrozen sirup, — which, from the standpoint of refresh-
ing qualities, should be an advantage. Reid13* found that consumers
prefer ice cream that is not too hard. He recommends a serving tem-
perature of about 10° F.
The device used in these tests for determining the relative hardness
of the ice cream was a %6-inch hollow brass rod with a tapered steel
point % inch long. The total length of the plunger was 32% inches,
and it was filled with lead filings until it weighed 510 grams. A
millimeter scale was imprinted on the rod. The rod was dropped a
distance of 13% inches thru a %6-inch tube into a frozen pint sample
of ice cream. The penetration of the plunger was then read on the
millimeter scale. Readings were made in triplicate and seldom varied
more than one millimeter.
In general at the lower temperatures, —12° to —8° F., the
dextrose ice cream was penetrated only slightly more than the sucrose
ice cream (Table 7). At higher temperatures the dextrose ice cream
had less resistance than the sucrose ice cream. This would indicate
that at the usual serving temperature (about 4° to 6° F.) the con-
sistency of dextrose ice cream would more nearly approach that
considered desirable by the consumer.
1939} DEXTROSE IN COMMERCIAL ICE CREAM 357
TABLE 7. — RELATIVE HARDNESS OF SUCROSE AND DEXTROSE ICE CREAMS
Composition of mix
Penetration in millimeters at:
Fat
Sucrose
Dextrose
-12" F.
-8°F.
0°F.
4°F.
8°F.
12° F.
Anhydrous dextrose ice creams
perct.
perct.
perct.
12
14
0
13.6
10.5
3.5
15.3
12
16
0
15.6
12
4.0
16.6
12
18
0
15.3
13.5
4.5
18
16
15
0
14
11.25
3.75
15.3
Hydrous dextrose ice creams
12
14
0
12
31
38
10.5
3.5
14.3
33
47
12
14
0
11.5
28.3
46
10.5
3.5
13.5
36
54
12
14
0
11.3
10.5
4.65
15.6
12
14
0
18
11
4.0
17
12
14
0
14.5
44
52
10.5
5.0
16
67
85
12
15
0
13
...
11.25
4.5
17
12
15
0
13 3
...
11.25
4.5
14 3
14
14
0
14
57
70
10.85
5.7
16.6
80
85
16
15
0
14
47
69
11.2
5.6
16
68
85
EFFECT OF TIME OF ADDING DEXTROSE TO MIX
A series of experiments were performed in which an attempt was
made to determine the importance of the time of adding dextrose to
the mix. It was found that adding dextrose after pasteurizing and
either before or after homogenizing had little or no influence on
whipping ability, body or flavor, dipping losses or hardness tests.
In one experiment a finely pulverized dextrose sugar was added to
the mix in the freezer after the ice cream had been partially frozen.
It would be an advantage if the dextrose could be successfully incor-
porated at this point so that it would not go into solution and depress
the freezing point. This method of adding the dextrose, however,
358 BULLETIN No. 452 [March,
caused a supercooling in the freezer and the resulting ice cream had
an objectionable powdery body, making the procedure undesirable.
COMPARISON OF DIFFERENT TYPES OF DEXTROSE
Three dextrose sugars commonly used by the different food indus-
tries were used in ice cream to compare their relative merits. These
sugars were the regular hydrous dextrose (a granulated refined
sugar), anhydrous dextrose (a highly purified granulated sugar),
and another highly purified granulated hydrous dextrose made chiefly
for the bottling industries.
When the above sugars were used in ice cream they gave approxi-
mately the same results. Anhydrous dextrose is more expensive per
pound than hydrous dextrose, but on a dry-matter basis it is only
slightly more expensive, and its use in ice-cream making might well
be considered, since sucrose can be replaced with anhydrous dextrose
pound for pound. The highly purified hydrous dextrose would be the
least practical of the three, because the extra processes required in its
manufacture make it more expensive than the regular dextrose, and
it gives no better results.
USE OF DEXTROSE IN COUNTER FREEZER MIX
For this experiment seven batches of ice cream varying in fat con-
tent from 12 to 16 percent were frozen on either a 2%- or 5-gallon-
capacity counter freezer. The use of dextrose had little or no effect on
the time required to remove the heat from the mix, or the time
required to whip to 100-percent overrun. The difference between the
minimum and the drawing temperatures of the dextrose ice creams
and those of the sucrose ice cream was approximately the same as
when the mixes were frozen on the larger freezer. It is doubtful if
these differences are great enough for the average counter freezer
operator to detect them. The University Creamery sold ice-cream mix
to a drug store that owned and operated a counter freezer, and during
part of the year 1935-36 one-fourth of the sucrose was replaced with
dextrose in the mix formula. Thruout this period this store did not
notice any difference in either the freezing or the dispensing.
USE OF DEXTROSE IN MIX WHEN FROZEN
ON VOGT CONTINUOUS FREEZER
In the first seven experiments with the continuous freezer a 2-tube
120-gallon capacity Vogt freezer was used in which 50- to 70-gallon
batches of mix were frozen. For the last experiment a new 60-gallon
1939]
DEXTROSE IN COMMERCIAL ICE CREAM
359
capacity single-tube Vogt freezer was used in which 25-gallon batches
were frozen. Mix pressure, refrigeration pressure and temperature,
overrun, mix temperature, and drawing temperature were taken at
5-minute intervals thruout the freezing period.
In these experiments it was found that the use of dextrose did not
affect the refrigeration pressure and temperature, the ability to obtain
overrun, or the capacity of the freezer, but lowered the drawing tem-
perature an average of 1.2 degrees in the first seven experiments, in
which one-fourth of the sucrose was replaced with dextrose, and an
average of .2 degree in Experiment 8, in which one-seventh of the
sucrose was replaced with dextrose (Table 8).
The most serious defect of the Vogt- frozen dextrose ice cream
was a heavy, soggy, or sticky body. This ice cream also gave an
TABLE 8. — DRAWING TEMPERATURES, MELT DOWN, AND BODY SCORES OF SUCROSE
AND DEXTROSE ICE CREAMS FROZEN ON VOGT CONTINUOUS FREEZER
(Composition of mix: 12.5 percent fat, 10.5 percent serum solids, and .3 percent egg)
Exp.
No.
Composition of mix
Average
drawing
temper-
ature
Type of
melt down
Body
Sucrose
Dextrose
Gelatin
Score
Criticism
1
Perct.
14
10.5
14
10.5
14
10.5
14
10.5
14
10.5
14
14
10.5
10.5
14
14
10.5
10.5
13.5
13.5
12.0
12.0
perct.
3~.s'
s'.s'
4.65
4! .25
4.25
i'.2S
4.25
4.25
4.25
2.2
2.2
perct.
(200 Bloom)
.37
.37
.37
.37
.39
.39
.39
.29
.39
.325
.39
.29
.39
.29
.39
.29
.39
.29
(250 Bloom)
.2
.3
.2
.3
°F.
23.7
23
21.2
20.45
23.9
23
23.9
22.5
22
20.3
24.2
23.7
22.5
22.5
23.7
23.1
22.5
22
21.8
21.9
21.5
21.8
Satisfactory
Abnormal,
slow
Satisfactory
Slow, ab-
normal
Satisfactory
Slow, ab-
normal
Normal
Normal
Slightly ab-
normal
Normal
Normal
Normal
Normal
Normal
24
24
24
24
24
23.75
24.25
24.5
24.5
23.75
23.75
24
23.5
23
24.5
23
23.5
24
Slightly coarse
Sticky
Slightly sticky
Slightly sticky
Slightly sticky
Sticky
Slightly sticky
Satisfactory
Satisfactory
Sticky
Slightly sticky
Satisfactory
Lacked resistance
Lacked resistance
Satisfactory
Slightly churned,
lacked resistance
Slightly sticky
Satisfactory
Lacked resistance
Good
Good
Slightly heavy
and soggy
2
3
4
5
6
7
8»
Normal
Normal
Slightly ab-
normal
Abnormal
•In Experiment 8 only one-seventh of the sucrose was replaced with dextrose.
360 BULLETIN No. 452 [March,
undesirable and abnormal melt down, flattening out and exuding a
rather clear serum during the first stages. Later it sloughed off the
sides. At the end of two hours it had melted only about two-thirds
as much as the control ice cream. Lowering the gelatin (200 Bloom)
content from .39 percent to .29 percent in the first seven experiments
remedied this defect. In Experiment 8, 250 Bloom gelatin was used
and the gelatin content was lowered from .3 percent to .2 percent,
which gave a more normal melt down.
The exact nature of the abnormal melt down is not entirely known
but seems to be closely correlated with protein stability and fat clump-
ing. It was found that when the melt down was abnormal, the thin
serum which exuded at the beginning was very low in fat and total
solids, and the last of the melt down was high in fat and total solids.
Alcohol tests showed that the ice creams which gave the abnormal
melt down were less stable.
In hardness, dipping losses, and flavor scores, the Vogt- frozen ice
cream was found to be similar to the batch-frozen ice cream.
PART II: EFFECT OF DEXTROSE ON CERTAIN
PHYSICAL AND CHEMICAL PROPERTIES
OF THE ICE-CREAM MIX
Since dextrose contains a functional aldehyde group, it is chemically
somewhat more active than sucrose. Therefore it might be expected
to react sufficiently with the proteins so that differences could be
detected by physical and chemical tests. With this in mind, an attempt
was made to determine the effect of dextrose on mix color, viscosity,
pH, curd tension, and protein stability.
For these tests small experimental mixes were made from 40-per-
cent cream, skimmilk, and concentrated skim. The mixes contained
12 percent fat, 10.5 percent serum solids, .35 percent gelatin, and
varying amounts of sugar, and were homogenized at 2,500 pounds
pressure.
Color
The color determinations were made thru photometric readings
with a Keuffel and Esser color analyzer, using wave lengths ranging
from 480 to 630 millimicrons. This procedure compares the color of
the mix with the color of magnesium carbonate, which is one of the
whitest substances known. The whiter the mix, the closer the color
reading approaches 100; the darker the mix, the closer the color
reading approaches zero.
1939]
DEXTROSE IN COMMERCIAL ICE CREAM
361
TABLE 9. — PHOTOMETRIC READINGS OF SUCROSE AND DEXTROSE MIXES
PASTEURIZED AT DIFFERENT TEMPERATURES'
Wave
length
Readings taken when mix was pasteurized at:
142° F.
150° F.
160° F.
Mixl
Mix 2
Mix 3
Mix 4
Mixl Mix 2
Mix 3
Mix 4
Mixl Mix 2 Mix 3 Mix 4
Readings taken on unaged mix
480
58
55
57
55
56.5
59
53.5
55.5
60
57
59
59
510
64 5
62
62 5
65
66 5
66.5
61.5
63
67
62
64
64
540
68.5
67
66.5
67
67
68
64.5
65
67
64
69
69
570
68.5
67
67
67
67.5
68
66
65
65
67
67
67
600
67.5
67.5
66
66
64
57
61
64
67
63
67
67
630
65
65
64
63.5
64
57
62.5
64
67
61.5
67
67
Readings taken after aging mix ten days at 40° F.
480
55
56
57
57
57
57
56
57.5
57
57
56
57.5
510
66
64
64
65.5
65
65
65
65
66
66
66
65
540 . .
71
71
70
67 5
70
68
70
70
70
67.5
70
67 5
570
70
71
71
68
69
68.5
70
67
70
68.5
70
69
600 . .
70
68
70
67 5
68
68
69
67.5
69
67
70
68
630
70
69
68
66
67.5
66
67
66.5
68
67
69
67.5
•Mixl: 14 percent sucrose. Mix 2: 12 percent sucrose, 3 percent dextrose. Mix 3: 8 percent
sucrose, 8 percent dextrose. Mix 4: 20 percent dextrose.
The results of photometric readings of mixes sweetened with
sucrose, with a mixture of sucrose and dextrose, and with all dextrose
are given in Table 9. The mixes were pasteurized for 30 minutes at
142° F., 150° F., and 160° F. Slightly more color was recorded when
dextrose was used, but the differences were not detectable by the
naked eye. The dextrose mixes pasteurized at 160° F. showed some-
what less color than those pasteurized at lower temperatures. The
samples held 10 days showed slightly less color than did the unaged
mix.
Photometric readings of mixes in which the sugar was added at
different stages during the processing are given in Table 10. The
mixes were pasteurized at 150° F. The samples in which the sugar
was added to the cold milk products and then pasteurized for 30
minutes were the most highly colored. The dextrose mixes were
slightly darker than the sucrose mixes, but the color differences were
so slight that they could be considered of no importance for all
practical purposes.
Sugar-and-water solutions were also made up and photometric
readings taken to determine whether the increase in color that had
been observed in the mixes was due to a dextrose-protein reaction or
whether the sugar itself caused an increase in color. In the unheated
sugar solutions it was impossible to detect any differences in amount of
362
BULLETIN No. 452
[March,
TABLE 10. — PHOTOMETRIC READINGS OF MIXES IN WHICH SUGAR WAS ADDED AT
DIFFERENT TIMES IN THE PROCESSING*
(Mixes were pasteurized 30 minutes at 150° F.)
Wave
length
Readings when sugar was added at time indicated
When batch was started
When pasteurization tem-
perature was reached
Just before cooling
Mixl
Mix 2
Mix 3
Mixl
Mix 2
Mix 3
Mixl
Mix 2
Mix 3
480
56
63
69
68
67
67.5
55
62
68
67.5
66
66.5
54
59
64.5
65
63
62.5
56.5
64
68.5
68.5
68
66.5
55.5
62.5
68.5
67.5
66.5
66
55
61.5
66
66
64.5
63.5
56
64
69
69
68.5
66
55.5
62.5
68
67.5
66.5
65.5
55
62
66
66
66.5
63.5
510 . . . .
540
570
600
630
•Mixl: 14 percent sucrose. Mix 2: 8 percent sucrose, 8 percent dextrose. Mix 3: 20 percent
dextrose.
color. In the samples which had been heated to 150° F. for 30 minutes
there was more color in the dextrose than in either cane or beet sugar
solutions (Table 11). The unheated sugar solutions were darker than
the heated solutions, probably because heating caused more complete
dispersion of the sugar, thus lessening the color.
There was as great a difference in the color of the sugar-and- water
solutions as in the color of the mixes to which the sugar was added
and then heated. This would suggest that the slight difference in
TABLE 11. — PHOTOMETRIC READINGS OF SUGAR-AND- WATER SOLUTIONS
Sugar content
of solution
Readings taken on wave length indicated
480
510
540
570
600
630
Solutions not heated
14 percent cane
13
13
13
13
13
16
16
15
15
15
16
16
16
16
15
17
17
17
17
17
17
17
17
17
17
17
16
17
17
17
14 percent beet
8 percent cane, 8 percent dextrose
8 percent beet, 8 percent dextrose
20 percent dextrose
Solutions heated to 150° F. for 30 minutes
14 percent cane
15.5
16
15
15
14
17.5
18
17
17
15.5
18
18
18
18
15.5
17.5
18.5
19
18
16
18
19
18
19
16
19
20
17
18
15
14 percent beet
8 percent cane, 8 percent dextrose
8 percent beet, 8 percent dextrose
20 percent dextrose
1939]
DEXTROSE IN COMMERCIAL ICE CREAM
363
color is not due to a reaction between dextrose and the mix
constituents, but to the sugar itself.
Viscosity
Within reasonable limits the degree of viscosity in a mix has no
particular significance. However, from an experimental point of view
it is of interest to know to what extent each of the ingredients entering
a mix may affect the viscosity. Anything which could cause a decided
increase or decrease in viscosity would likely be considered undesirable
by the ice-cream manufacturers, altho slight variations in this respect
would be of little consequence.
In these tests the viscosity of sucrose and dextrose mixes was
measured with a MacMichael viscosimeter. The results of these
measurements for mixes heated at varying temperatures for different
periods of time are given in Table 12. These mixes were all heated
to 142° F. and homogenized. They were then given the additional
heat treatment indicated in the table. The additional holding time
resulted in nearly all cases in a reduced viscosity, there being little
difference in the effect of the two sugars in this respect. Increasing
the amount of dextrose increased the viscosity of the mix, which was
heated to pasteurizing temperature and cooled immediately, but the
viscosity generally grew less the longer the mix was held at the pas-
teurization temperature.
According to the data in Table 13, dextrose has a tendency to
reduce mix viscosity. Tests on pairs of comparable batches showed
TABLE 12. — VISCOSITY OF SUCROSE AND DEXTROSE MIXES HEATED AT DIFFERENT
TEMPERATURES FOR DIFFERENT PERIODS OF TIME"
Sugar content
of mix
Viscosity in degrees MacMichael when mix was held at
temperature and for time indicated
142° F.
150° F.
160° F.
0'
30'
60'
0'
30'
60'
0'
30'
60'
14 percent sucrose
98
98
101
103
96
94
90
95
93
90
91
89
99
108
108
100
92
92
94
88
88
92
87
83
99
92
91
97
92
96
90
76
86
86
95
90
12 percent sucrose, 3 percent
dextrose
8 percent dextrose, 8 percent
sucrose
20 percent dextrose
•Measured at 45° F. with a No. 30 wire.
364
BULLETIN No. 452
[March,
TABLE 13. — VISCOSITY OF COMPARABLE BATCHES OF SUCROSE
AND DEXTROSE ICE CREAM"
Trial
Composition of mix
Viscosity
(degrees
MacMichael)
Fat
Sucrose
Dextrose
1
percl.
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12.5
12.5
12.5
12.5
13
13
14
14
16
16
perct.
14
10.5
14
10.5
14
10.5
14
10.5
14
10.5
16
12
18
13.5
15
11.25
14
10.5
13.5
12
13.5
12
14
10.5
14.5
10.85
15
11.25
perct.
0
5.0
0
4.2
0
4.2
0
4.2
0
3.5
0
4.0
0
4.5
0
4.5
0
3.5
0
2.2
0
2.2
0
4.65
0
5.7
0
3.75
66.5
40
100
87
88
61
49.5
44
71
88
68
90
86
97
26
40
83
60
21
18.5
31.25
25.75
141
96
82
70
260
249
2
3
4
5t>
6b
?b
8
9
10
11
12
13
14
"Viscosity measured with No. 26 wire.
bSugar added to mixes after the other products had been processed.
that in 11 out of 14 trials the viscosity of the dextrose-sucrose mixes
was less than that of the all-sucrose mixes.
A series of sugar-gelatin-water solutions were also made up and
heated at 150° F. for 30 minutes and viscosities determined to see
whether or not the dextrose had inhibited the hydration of the gelatin.
The data in Table 14 indicate that dextrose did not affect the viscosity
of such solutions.
Acidity
A portable Leeds and Northrup quinhydrone outfit was used for
measuring the hydrogen-ion concentration of all-sucrose, part-dex-
trose, and all-dextrose mixes. The mixes containing dextrose were
1939}
DEXTROSE IN COMMERCIAL ICE CREAM
365
TABLE 14. — VISCOSITY OF GELATIN-WATER SOLUTIONS TO
WHICH SUCROSE, MIXTURES OF SUCROSE AND DEX-
TROSE, OR DEXTROSE, WAS ADDED*
(Solutions heated at 150° F. for 30 minutes)
Gelatin
used
Composition of solution
Viscosity
(degrees
MacMichael)
Gelatin
Sucrose
Dextrose
A
perct.
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
.45
perct.
0
20
15
10
5
0
0
20
15
10
5
0
0
20
15
10
5
0
0
20
15
10
5
0
20
15
10
5
0
perct.
0
0
5
10
15
20
0
0
5
10
15
20
0
0
5
10
15
20
0
0
5
10
15
20
0
5
10
15
20
3.5
7
7
7
7.5
7
4
8
8
8.5
8.5
8
6
9
9
9.25
9
8.5
25
46
47.5
46.5
44.5
45.5
61.5
58
61
57
60
B
c
Db
Dib
•Viscosity measurements were made with a No. 26 wire.
bViscosity of Gelatins D and Di was measured with a No. 30 wire. Gel-
atin Di was the same as D, but gelatin-and-sugar solutions were made up and
heated separately and then combined in the correct proportion after the solu-
tions had cooled. Viscosity was measured after 24 hours.
TABLE IS. — EFFECT OF DEXTROSE ON pH OF MIXES*
pH of mix pasteurized at temperature indicated
Pasteur-
izing
time
142° F.
150° F.
160° F.
Mixl
Mix 2
Mix 3
Mix 4
Mixl
Mix 2
Mix 3
Mix 4
Mixl
Mix 2
Mix 3
Mix 4
0 minutes .
6.5
6.52
6.47
6.45
6.4
6.35
6.35
6.25
6.4
6.25
6.32
6.25
30 minutes .
6.35
6.34
6.32
6.23
6.4
6.32
6.28
6.20
6.45
6.45
6.40
6.35
60 minutes
6.42
6.45
6.40
6.32
6.35
6.35
6.35
6.25
6.55
6.52
6.50
6.40
•Mixl: 14 percent sucrose. Mix 2: 12 percent sucrose, 3 percent dextrose. Mix 3: 8 percent
sucrose, 8 percent dextrose. Mix 4: 20 percent dextrose.
366
BULLETIN No. 452
[March,
from 0 to .2 lower in pH than the all-sucrose mixes (Table 15). The
greatest decrease took place when dextrose was the only sugar used.
An experiment was also made to determine the effect on pH of
the extent of the heat treatment given the mix. The longer the milk
TABLE 16. — EFFECT ON pH OF EXTENT OF HEAT TREATMENT GIVEN Mix
(Pasteurizing temperature, 150° F.)
Sugar content
of mix
pH of mix after treatment indicated
Sugar dissolved in
mix at 150° F.;
mix cooled
immediately
Sugar added to
cold mix; mix
heated to 150° F.
and held 30 min.
Sugar added to
cold mix; mix
heated to 150° F.
and held 60 min.
14 percent sucrose
6.46
6.41
6.41
6.46
6.42
6.36
6.44
6.35
6.28
8 percent sucrose, 8 percent dextrose
20 percent dextrose
TABLE 17. — HYDROGEN-!ON CONCENTRATION AND TITRATABLE ACIDITY OF
SUCROSE AND DEXTROSE MIXES
Composition of mix
PH
Titratable
acidity
Fat
Serum solids
Sucrose
Dextrose
perct.
12
12
perct.
10.5
10.5
perct.
14
10.5
perct.
0
5
6.48
6.415
perct.
14
14
10
10
14.5
10.85
0
5.7
6.51
6.51
16
16
9
9
15
11.2
0
5.6
6.45
6.405
16
16
9
9
15
11.25
0
3.75
6.39
6.39
.155
.165
12
12
10.5
10.5
14
10.5
0
4.2
6.395
6.395
.22
.21
12
12
10.5
10.5
15
11.25
0
4.5
6.40
6.39
.24
.25
12
12
12
12
14
10.5
0
3.5
.23
.25
12
12
12
12
16
12
0
4.0
.23
.24
12
12
12
12
18
13.5
0
4.5
.24
.24
16
16
9
9
15
11.25
0
3.75
.17
.18
Average for dext
Average for sucrc
•ose mixes
6.417
6.437
.219
.212
>se mixes
1939]
DEXTROSE IN COMMERCIAL ICE CREAM
367
products were heated in combination with the dextrose, the lower the
pH (Table 16). The greatest decrease in pH took place when
dextrose was used as the sole sweetener. When only part of the
sucrose was replaced with dextrose and the mix was pasteurized at
150° F. for 30 minutes, the decrease was slight.
A comparison of the acidity of a number of mixes of varying fat
and sugar content made up in 100- to 500-pound batches was also
made. The part-dextrose mixes tended to be slightly lower in pH and
higher in titratable acidity, but the differences were too small to be
significant (Table 17).
Curd Tension
In order to get a more accurate picture of what changes might
take place between the dextrose and the milk protein, the curd tension
of mixes to which different sugars were added was determined. A
modification of the Hill10* curd test was used to measure the firmness
of the coagulum formed when the ice-cream mix was coagulated with
a calcium chlorid plus pepsin solution. The curd tension was measured
in grams which represent the force required for a standard star-shaped
knife to be pushed thru the coagulated curd. The dextrose was found
to exhibit no measurable effect on the curd tension (Table 18).
In further studies the sugar was added to the mix at different
times: it was added to the cold milk products before the mix was
processed; added to the mix before pasteurizing but as soon as the
other products had reached pasteurizing temperature ; and added after
pasteurizing and just before cooling. The time at which the sugar was
added to the mix was found to have no effect on the curd tension.
TABLE 18. — CURD TENSION OF SUCROSE AND DEXTROSE ICE-CREAM MIXES
(Mixes contained 12 percent fat and 10.5 percent serum solids)
Sugar content
of mix
Curd tension when pasteurized at temperature
and time indicated
142° F.
ISO" F.
160° F.
0' 30' 60'
0' 30' 60'
0' 30' 60'
14 percent sucrose
grams
26 23 23
22 24 24
20 22 24
22 23 22
grams
24 22 23
24 28 24
20 26 22
22.5 24 25
grams
20 22 20
22 25 18.5
21 20 18
20 22 22
12 percent sucrose, 3 percent dextrose
8 percent sucrose, 8 percent dextrose
20 percent dextrose
368
BULLETIN No. 452
[March,
TABLE 19. — PROTEIN STABILITY OF MIXES SWEETENED WITH SUCROSE, SUCROSE
AND DEXTROSE, AND DEXTROSE
Sugar content
of mix
Measure of protein stability* when pasteurized at
temperature and for time indicated
142° F.
150° F.
160° F.
0' 30' 60'
0' 30' 60'
0' 30' 60'
14 percent sucrose
5.3 5.3 5.1
5.0 5.9 5.2
5.3 5.2 5.2
5.5 5.8 5.0
4 4.2 5.6
4.3 4.8 4.9
4.1 5.0 5.0
4.2 5.5 5.0
4.4 4.5 4.5
4.8 4.7 4.9
4.3 4.5 4.9
4.4 4.4 4.8
12 percent sucrose, 3 percent dextrose
8 percent sucrose, 8 percent dextrose
20 percent dextrose
'Cubic centimeters of alcohol required to start precipitation in a 2-cc sample of mix diluted
with an equal amount of distilled water.
Protein Stability
The alcohol test was used to measure the protein stability of the
mix. A 2-cc sample of mix was diluted with an equal amount of dis-
tilled water and then 95-percent ethyl alcohol was added until the
first signs of precipitation occurred. With this method it is some-
times rather difficult to determine the correct end-point, but the
method is accurate enough to give the information desired.
No correlation was found between the sugar used and the stability
of the protein (Table 19). Even when dextrose was used as the sole
source of sugar, the alcohol tests were as high as they were when
sucrose was used. Adding dextrose and sucrose at different intervals
in the processing had no effect on the protein stability of the mixes.
PART III: CONSUMER PREFERENCE STUDIES ON
QUALITIES OF PART-DEXTROSE AND
ALL-SUCROSE ICE CREAMS
After it was shown that dextrose could be successfully used in
the manufacture of commercial ice cream, and that it had no detri-
mental effect upon certain physical and chemical properties of the mix,
it remained to determine to what extent ice cream containing dextrose
would be acceptable to the consumer. While it is realized that the
accuracy of data secured from consumer studies is open to some
criticism, such data do help in determining the general likes and
dislikes of the consuming public. About 500 people in nine different
groups took part in these consumer studies.
1939] DEXTROSE IN COMMERCIAL ICE CREAM 369
ICE CREAMS JUDGED FOR BODY, FLAVOR AND SWEETNESS
The ice-cream samples were prepared in the same way as those
for the consumer tests described in Part I. Most of the ice cream was
frozen to 100-percent overrun and served from gallon containers; the
remainder was frozen to 80-percent overrun and served in bricks. A
reproduction of the questionnaire which was filled out by the
consumers is given below.
Experiment No
1. Did you notice any difference in the flavor of the ice creams? If so,
which flavor did you prefer and why?
2. Did you notice any difference in the body of the ice creams?
If so, which ice cream did you think had the best body?
3. Did you notice any difference in the sweetness of the two ice creams?
If so, which had the sweeter taste?
4. Were you hungry at the time of the judging?
5. Do you enjoy eating ice cream?
Occupation Sex.
When Hydrous Dextrose Was Given a Sweetening Value of 70
In this experiment one- fourth of the sucrose was replaced with
hydrous dextrose at the rate of 1.43 pounds of dextrose per pound of
sucrose, giving the corn sugar a sweetening value of 70 compared with
a sweetening value of 100 for the cane sugar. The ice creams were of
the following compositions: (1) 12 percent fat, 10.5 percent serum
solids, 14 percent sugar, .35 percent gelatin, and .3 percent dried egg
yolk; (2) 14 percent fat, 10 percent serum solids, 14.5 percent sugar,
.33 percent gelatin, and .30 percent dried egg yolk; (3) 16 percent fat,
9 percent serum solids, 15 percent sugar, .30 percent gelatin, and .30
percent dried egg yolk. The mixes were frozen on a 40-quart direct-
expansion batch freezer.
The dextrose ice cream was found to be comparable to the sucrose
ice cream in body and flavor but was considered much sweeter (Table
20). The most common criticisms, or reasons for preferences, are
given in Table 21. Many of the consumers thought that the dextrose
ice cream tasted richer or creamier than the sucrose ice cream. It is
probable that the slightly different type of body produced by the dex-
trose could account for the seemingly richer flavor.
The data in Tables 20 and 21 show quite conclusively that when
dextrose is used to replace a fourth of the sucrose, a sweetening value
of 70 for dextrose is too low.
370
BULLETIN No. 452
[March,
TABLE 20. — CONSUMER COMPARISON OF PART-DEXTROSE AND ALL-SUCROSE ICE
CREAMS FOR BODY, FLAVOR, AND SWEETNESS, WHEN ONE-FOURTH OF
SUCROSE WAS REPLACED WITH HYDROUS DEXTROSE
GIVEN A SWEETENING VALUE OF 70
Kind of
sweetening
Number preferring
quality indicated
Number
choosing ice
cream as
sweeter
Number finding no difference in
quality indicated
Body
Flavor
Body
Flavor
Sweetness
12 percent fat in mix
Sucrose
146
161
118
144
83
172
48
93
100
Dextrose
14 percent fat in mix
63
22
37
25
36
33
10
33
23
Dextrose
16 percent fat in mix
Sucrose
106
103
87
85
77
103
33
70
62
All mixes
Sucrose
315
286
242
254
196
308
91
196
185
Dextrose
TABLE 21. — CONSUMER COMMENTS ON PART-DEXTROSE (HYDRATE) AND ALL-
SUCROSE ICE CREAMS WHEN DEXTROSE WAS GIVEN A
SWEETENING VALUE OF 70
Reason for preference
12 percent fat
14 percent fat
16 percent fat
Sucrose
Dextrose
Sucrose
Dextrose
Sucrose
Dextrose
Number of persons basing preference on reason indicated
Not so sweet
17
8
5
9
7
8
3
14
5
28
49
0
19
3
1
10
2
8
2
0
5
1
1
10
0
4
0
0
2
0
0
6
16
11
7
8
10
5
6
9
5
15
23
4
11
4
5
12
Sweeter
Richer or creamier
Not so rich
Smoother body
Better texture and body
Firmer body
Better flavor
1939]
DEXTROSE IN COMMERCIAL ICE CREAM
371
TABLE 22. — CONSUMER COMPARISON OF PART-DEXTROSE AND ALL-SUCROSE ICE
CREAMS FOR BODY, FLAVOR, AND SWEETNESS, WHEN ONE-FOURTH OF
SUCROSE WAS REPLACED WITH HYDROUS DEXTROSE
GIVEN A SWEETENING VALUE OF 100
Kind of
sweetening
Number preferring
Quality indicated
Number
choosing ice
cream as
sweeter
Number finding no difference in
quality indicated
Body
Flavor
Body
Flavor
Sweetness
Sucrose
104
146
125
87
153
79
34
72
52
Dextrose
When Hydrous Dextrose Was Given a Sweetening Value of 100
The ice cream used for this test contained 12 percent fat, 11.5
percent serum solids, 14 percent sugar, .37 percent gelatin, and .30
percent dried egg yolk. The mix was frozen on a Vogt continuous
freezer having a capacity of 120 gallons an hour. The body of the
dextrose ice cream was considered sticky by the authors, and the cane-
sugar ice cream was considered sweeter than the dextrose. The
majority of consumers also found the sucrose ice cream sweeter
(Table 22), indicating that in sweetening value a pound of hydrous
dextrose is not equivalent to a pound of sucrose. The flavor of the
sucrose ice cream was preferred by about as many consumers as
judged that ice cream sweeter than the dextrose.
It is interesting to note the decided preference for the body of the
dextrose ice cream altho the authors had criticized it as slightly heavy
and sticky.
The most numerous comments on the body and flavor of the two
ice creams are given in Table 23.
TABLE 23. — CONSUMER COMMENTS ON PART-DEXTROSE
(HYDRATE) AND ALL-SUCROSE ICE CREAMS WHEN DEXTROSE
WAS GIVEN A SWEETENING VALUE OF 100
(Both sucrose and dextrose mixes contained 12 percent fat)
Reason for preference
Sucrose
Dextrose
Number of persons basing prefer-
ence on reason indicated
31
10
5
24
9
14
6
14
7
21
0
14
Not so sweet
Smoother body
Body not so heavy or gummy
Better flavor
372
BULLETIN No. 452
[March,
When Hydrous Dextrose Was Given a Sweetening Value of 83.5
Since the consumer tests indicated that the dextrose ice cream was
much sweeter than the all-sucrose ice cream when one-fourth of the
sucrose was replaced by dextrose at the rate of 1.43 pounds of
dextrose per pound of sucrose, and not so sweet as the sucrose ice
cream when the dextrose replaced the sucrose pound for pound,
TABLE 24. — CONSUMER COMPARISON OF PART-DEXTROSE AND ALL-SUCROSE ICE
CREAMS FOR BODY, FLAVOR, AND SWEETNESS, WHEN ONE-FOURTH OF
SUCROSE WAS REPLACED WITH HYDROUS DEXTROSE
GIVEN A SWEETENING VALUE OF 83.5
Kind of sweetening and
gelatin content
Number of consumers
preferring quality
indicated
Number of
consumers
choosing ice
cream as
sweeter
Number of consumers finding no
difference in quality
indicated
Body
Flavor
Body
Flavor
Sweetness
Sucrose, .39 percent gelatin
Dextrose, .325 percent gelatin . .
SO
19
31
22
30
24
9
25
24
Sucrose, .39 percent gelatin
Dextrose, .29 percent gelatin. . .
54
25
42
20
34
32
10
27
23
another experiment was made in which 1.2 pounds of dextrose was
used to replace one pound of sucrose, this amount being the median
derived from the sweetening values given to dextrose in the two pre-
ceding experiments. The sucrose mix contained 12.5 percent fat, 10.75
percent serum solids, 14 percent sugar, .39 percent gelatin, and .30
percent dried egg yolk. For the dextrose ice creams the fat and serum
solids were the same as for the all-sucrose mix, but the gelatin con-
tent was lowered to .325 percent and to .29 percent, as it had been
previously shown (Part I) that a reduction of the gelatin content in
the mix would prevent or lessen the heaviness or stickiness in the body
of the Vogt-frozen dextrose ice creams. These ice creams were also
frozen on a Vogt continuous freezer.
The authors were of the opinion that the all-sucrose ice cream had a
slightly sticky body, but that the dextrose ice cream was free from
that defect. However, the body of the sucrose ice cream was much
preferred by the consumers, and this may have influenced their
preference for the flavor of that ice cream also.
The fact that the opinions on sweetness were about evenly divided
indicates that a sweetening value of 83.5 for dextrose (compared with
100 for sucrose) is quite close to its actual value.
1939]
DEXTROSE IN COMMERCIAL ICE CREAM
373
TABLE 25. — CONSUMER COMPARISON OF PART-DEXTROSE AND ALL-SUCROSE ICE
CREAMS FOR BODY, FLAVOR, AND SWEETNESS, WHEN ONE-FOURTH OF SUCROSE
WAS REPLACED POUND FOR POUND WITH ANHYDROUS DEXTROSE
Kind of
sweetening
Number preferring
quality indicated
Number
choosing ice
cream as
sweeter
Number finding no difference in
quality indicated
Body
Flavor
Body
Flavor
Sweetness
Sucrose
57
40
41
48
52
46
28
36
27
Dextrose
When One-Fourth of the Sucrose Was Replaced With
Anhydrous Dextrose Pound for Pound
Anhydrous dextrose differs from the regular dextrose in that it
is slightly more refined and is moisture- free. These qualities should
raise its sweetening value above that of the regular dextrose.
To determine the correct sweetening value of anhydrous dextrose
anci to measure consumer preferences, a mix was prepared containing
16 percent fat, 9 percent serum solids, 15 percent sugar, .30 percent
gelatin, and .30 percent dried egg yolk. In the dextrose ice cream one-
fourth of the sucrose was replaced with anhydrous dextrose pound
for pound. The ice creams were frozen on a 40-quart direct-expansion
batch freezer.
These ice creams were given similar scores by the authors. The
consumer tests (Table 25) show that in sweetness and flavor anhy-
drous dextrose is comparable to sucrose. The body of the cane-sugar
ice cream was preferred by the greater number of consumers.
COMPARISON OF ICE CREAMS FOR THEIR
REFRESHING QUALITIES
The dextrose-sweetened ice cream seemed to the authors to have
a slightly shorter texture, to melt down faster on the tongue, and to be
slightly less chewy than ice cream sweetened entirely with sucrose.
These qualities should make the dextrose more cooling or refreshing.
In order to test this hypothesis, mixes were prepared containing 12
percent fat, 10.75 percent serum solids, 14 percent sugar, .35 percent
gelatin, and .30 percent dried egg yolk. Data were also obtained on
mixes of 16 percent fat, 9 percent serum solids, 15 percent sugar, .30
percent gelatin, and .30 percent dried egg yolk. In the dextrose mixes
one-fourth of the sucrose was replaced with anhydrous dextrose
pound for pound.
374
BULLETIN No. 452
[March,
TABLE 26. — CONSUMER OPINIONS CONCERNING REFRESHING QUALITIES OF
SUCROSE AND DEXTROSE ICE CREAMS
Sucrose
Dextrose
No
difference
16 percent fat in mix
Number preferring ice cream indicated
41
33
75
43
11
51
Number judging ice cream most refreshing
12 percent fat in mix
Number preferring ice cream indicated
72
44
29
25
15
47
Number judging ice cream most refreshing
The ice creams were frozen on a 40-quart direct-expansion batch
freezer and were served on very warm days. They were given similar
scores by the authors. The following type of questionnaire was used
for the consumer tests.
Questionnaire:
Which of the ice creams do you prefer?
What are the reasons for your choice?
Do you notice any difference in the refreshing qualities of the ice creams?
If so, which one do you consider most refreshing?
Do you consider the regular commercial ice cream on the market satis-
factory from the standpoint of refreshment?
Occupation Sex
Consumers did not find much difference between the dextrose-
TABLE 27. — CONSUMER COMMENTS ON PART-DEXTROSE (ANHYDRATE) AND ALL-
SUCROSE ICE CREAMS WHEN DEXTROSE WAS GIVEN A
SWEETENING VALUE OF 100
Reason for preference
12 percent fat in mix
16 percent fat in mix
Sucrose
Dextrose
Sucrose
Dextrose
Number basing preference on reason indicated
Sweeter
25
9
9
17
9
1
17
4
9
3
3
1
7
8
3
10
0
3
9
5
7
25
5
17
13
16
6
24
Not so sweet
Richer and creamier
Smoother body
Better body and texture
Firmer body
Better flavor
1939] DEXTROSE IN COMMERCIAL ICE CREAM 375
sweetened and the all-sucrose sweetened ice creams from the stand-
point of their refreshing qualities. When the mix contained 16 percent
fat, dextrose was preferred to the all-cane-sugar ice cream (Table 26).
Consumers thought it was sweeter, richer, and creamier than the
all-sucrose ice cream, and that it had better flavor, body, and texture
(Table 27). This decision was reversed when the mix contained only
12 percent fat.
SUMMARY
Studies were made of the adaptability of dextrose for use in
commercial ice cream. In most of the tests one- fourth of the sucrose
was replaced with dextrose in the dextrose mixes. The part-dextrose-
sweetened ice creams and the all-sucrose-sweetened ice creams were
compared for sweetness, body and flavor, sandiness, whipping ability,
melt down, hardness, and dipping losses. The time of adding dextrose
to the mix, different types of dextrose sugars, and the effect of freez-
ing dextrose mixes in the counter freezer and the Vogt continuous
freezer were also studied. In addition, the effect of dextrose upon
certain physical and chemical properties of the mix was determined,
and consumer tests of the various ice creams were made.
Sweetening Value. — In water solution dextrose had a sweetening
value of approximately 65 to 75, compared with 100 for cane sugar,
but its sweetening value was greater than this when it was used in
conjunction with sucrose in ice cream. Consumer tests showed that
when one-fourth of the sucrose for an ice-cream mix was replaced with
dextrose, one pound of hydrous dextrose was equivalent in sweetness
to .83 pound of sucrose, and that anhydrous dextrose could replace
cane or beet sugar pound for pound.
Whipping Ability. — Dextrose-sucrose mixes frozen on 10-, 12-, 20-,
and 40-quart direct-expansion batch freezers whipped to 100 percent
overrun in about the same time as did all-sucrose mixes.
Minimum and Drawing Temperatures. — The time required to
remove the heat from both mixes was practically the same. The
average drawing temperature of the dextrose ice cream was 1 degree
Fahrenheit lower than that of the all-sucrose ice cream when frozen in
the batch freezer and 1.2 degrees lower when frozen in the Vogt
freezer.
Flavor, Body, Melt Down, and Sandiness. — When used to replace
one-fourth of the sucrose, dextrose had little or no effect on flavor or
body scores. The dextrose ice cream melted down slightly more
376 BULLETIN No. 452 [March,
rapidly than the all-sucrose ice creams, tho the percentage loss in
weight at 60 to 90 minutes was rarely more than 2 to 5 percent
greater. When dextrose was used to replace one- fourth of the sucrose
in high-serum-solids mixes, there was a slight delay in the development
of sandiness.
Dipping Losses. — Owing to differences in hardness, dipping losses
for dextrose ice cream were slightly higher than for sucrose ice cream
when the dipping was done at the same temperature; but when the
dipping temperature for the dextrose ice cream was lowered approxi-
mately 1 degree for each percent of dextrose, the dipping loss was
comparable to that of the sucrose ice cream.
Hardness. — Tests run at — 12° to 0° F. showed no difference in
hardness between the dextrose and sucrose ice creams, but at higher
temperatures the dextrose ice cream became less resistant than the
sucrose ice cream.
Time of Adding Dextrose. — The time at which, during the proc-
essing of the mix, the dextrose was added made no difference in the
freezing and whipping processes. Adding a finely pulverized dextrose
to the mix at the freezer during the freezing process produced super-
cooling in the freezer and caused a powdery body in the ice cream.
Effect of Different Types of Dextrose. — In a comparison of
hydrous dextrose, anhydrous dextrose, and a highly purified hydrous
dextrose, comparable results were obtained when the sugars were
used in the mix on the same dry-matter basis.
Types of Freezers. — Approximately the same results were obtained
with the dextrose mixes frozen in the 2%- and 5-gallon counter
freezers as were obtained with the larger batch freezers. When dex-
trose was used in mix frozen on the Vogt continuous freezer, the
drawing temperature was lowered, but neither mix pressure nor the
ability to obtain overrun was affected. However, the ice cream contain-
ing dextrose had a sticky body. This difficulty was overcome by a
reduction of the gelatin content.
Color. — In the study of the effect of dextrose on certain chemical
and physical properties of the mix, it was noted that dextrose mixes
had slightly more color, as determined by the color analyzer, but that
there was not enough difference to be perceptible to the eye. Replacing
one-fourth of the sucrose with dextrose had practically the same
effect on color as replacing all the sucrose with dextrose. The time
at which the sugar was added to the batch had only a slight effect on
the amount of color in the mix. Adding the sugar immediately before
cooling produced the least color increase in the mix.
1939] DEXTROSE IN COMMERCIAL ICE CREAM 377
Viscosity. — Dextrose had no effect on the viscosity of sugar-
gelatin-water solutions, but usually lowered the viscosity of the ice-
cream mix processed in the usual way. When the sugars were added
after the milk products had been pasteurized and homogenized, the
dextrose mixes gave a slightly higher viscosity.
pH. — Dextrose generally lowered the pH slightly, depending on
the time and temperature of pasteurizing and the percentage of dex-
trose in the mix. The maximum decrease observed in this study was
.2 in pH. When one- fourth of the sucrose was replaced with dextrose
there was an average decrease of .02 in pH.
Protein Stability and Curd Tension. — Dextrose had no measurable
effect on the protein stability or on the curd tension of the ice-
cream mix.
Consumer Preferences. — When one-fourth of the sucrose was
replaced with hydrous dextrose at the rate of 1.43 pounds of dextrose
per pound of sucrose omitted, the dextrose ice cream was comparable
to the sucrose ice cream in body and flavor but was considered much
sweeter by most judges.
When one-fourth of the sucrose was replaced with hydrous
dextrose pound for pound and the ice cream frozen on the Vogt
freezer, the body of the dextrose ice cream was much preferred to
the body of the all-sucrose ice cream. In flavor and sweetness the
all-sucrose ice cream was preferred.
When one- fourth of the sucrose was replaced with hydrous dex-
trose at the rate of 1.2 pounds of dextrose per pound of sucrose
omitted, and the mixes were frozen on a Vogt continuous freezer, the
body and flavor of the all-sucrose ice creams were preferred by a ma-
jority of the consumers. In these tests the gelatin content of the dex-
trose mixes was reduced below that of the all-sucrose ice cream so as
to prevent the dextrose ice cream from having a sticky body. These
ice creams were rated by the consumers as comparable in sweetness.
When one-fourth of the sucrose was replaced with anhydrous
dextrose pound for pound, dextrose ice cream in the opinion of con-
sumers was comparable in flavor and sweetness with the all-sucrose
ice cream. In this test the body of the all-sucrose ice cream was
preferred by the greater number of consumers.
In the test of refreshing qualities the consumers preferred the all-
sucrose ice cream when the mix contained 12 percent fat, and pre-
ferred the part-dextrose ice cream when the mix contained 16
percent fat.
378 BULLETIN No. 452 [March,
CONCLUSIONS
The following conclusions apply to ice creams sweetened with
sucrose as compared with those in which one-fourth of the sucrose is
replaced with dextrose.
1. Consumer tests show that hydrous dextrose has a sweetening
value which is 83 percent as effective as sucrose in ice creams, and
anhydrous dextrose has a value equal to sucrose.
2. The use of dextrose in ice cream does not affect the time to
freeze and whip the mix.
3. When 25 percent of the sucrose is replaced with dextrose the
drawing temperature will be approximately one degree lower.
4. Dextrose imparts as desirable flavor and body to batch-
frozen ice cream as does sucrose. When dextrose ice cream is frozen
on the Vogt continuous freezer, the stabilizer content must be reduced
in order to avoid a sticky body.
5. Dextrose ice cream melts slightly faster at room temperature,
which possibly accounts for the greater refreshing qualities of high-
fat ice creams having one- fourth of the sucrose replaced with dextrose.
6. Dipping the dextrose ice cream at lower temperatures than the
sucrose ice cream helps to minimize dipping losses.
7. Dextrose imparts slightly more color to the mix, slightly
lowers the pH, and decreases mix viscosity.
LITERATURE CITED
1. ANTHONY, R. S. and LUND, A. A. Repressing sandiness in ice cream by the
use of corn sugar. Ice Cream Trade Jour. 27, No. 10, 60-62. 1931.
2. AYERS, S. H., WILLIAMS, O. E., and JOHNSON, W. T., Jr. Sugar substi-
tutes in the ice cream mix. Ice Cream Trade Jour. 14, No. 4, 29-30.
1918.
3. BIERMAN, H. R. The effect of overrun, temperature and composition on
the dipping losses of ice cream. Md. Agr. Exp. Sta. Bui. 293. 1927.
4. COMBS, W. B. How corn sugar in an ice cream mix affects the harden-
ing process. Ice Cream Trade Jour. 23, No. 1. 1927.
5. and BELE, FRANK. Cerelose in ice cream. Ice Cream Rev.
10, No. 4, 66, 106-112. 1926.
6. Improving quality with corn sugar. Ice Cream
Rev. 10, No. 5, 132-140. 1926.
7. CORN INDUSTRIES RESEARCH FOUNDATION. Corn in industry. 1936.
8. ERB, J. H. Controlling sandiness in ice cream by using a combination
of sugars. Ice Cream Trade Jour. 27, No. 8, 35. 1931.
9. FRANDSEN, J. H., ROVNER, J. W., and LUITHLY, J. Sugar-saving substitutes
in ice cream. Neb. Agr. Exp. Sta. Bui. 168, 1918.
1939] DEXTROSE IN COMMERCIAL ICE CREAM 379
10. HILL, R. L. A decade and a half of soft-curd milk studies. Utah Agr.
Exp. Sta. Circ. 101. 1933.
11. MACK, M. J. Defects of high solids mixes and their cure. Ice Cream
Field 27, No. 3, 24-27. 1935.
12. MARTIN, W. H. How much sugar? What kind? Ice Cream Trade Jour.
23, No. 3, 44-45. 1927.
13. REID, W. H. E. and ARBUCKLE, W. S. Some factors affecting the serving
and dipping temperatures of ice cream. Jour. Dairy Sci. 20, No. 7,
456. 1937.
14. TRACY, P. H. and McCowN, C. Y. A study of factors related to the
hardening of ice cream. Jour, of Dairy Sci. 17, No. 1, 47-60. 1934.
APPENDIX
Modern Method of Manufacturing Dextrose
The initial step in the manufacture of dextrose from corn grain is the
efficient separation of the grain into the following portions: that which is
water soluble, the germ, the hull or fiber, the starch, and the gluten. The
shelled corn is soaked in warm water from 30 to 60 hours in large cylin-
drical tanks called steeps. The softened grain is then ground between two
close-set plates revolving in opposite directions. The grain of corn is
cracked or torn to pieces without injury to the germ, after which it passes
into deep rectangular tanks called germ separators. There the germ con-
taining the oil floats on the surface because it is lighter in specific gravity
than the rest of the cracked grain, which settles, is drawn off the bottom
of the separator, and is sent to the Buhr Mills. The grinding in this mill
completely separates all particles of hull from the starch and gluten. This
finely ground mixture is then passed over a silk sieve thru which the
starch and gluten pass with the water and are separated from the hull and
fiber. The mixture of starch and gluten which passes thru the silk sieves
is sent to the starch tables which are slightly inclined wooden troughs
about 2 feet wide and 120 feet long.
The starch, being heavier than the gluten, settles out on these tables in
a solid cake, while the gluten flows over the end of the table with the
water. The starch deposited on the table is removed by flushing with fresh
water, which again puts the starch in suspension. This starch suspension
is filtered several times to remove all impurities, after which it is diluted to
a Baume of about 13°. The suspension is then acidulated with hydrochloric
acid and cooked under pressure in bronze tanks at a temperature of
approximately 275° F. This cooking is continued until all the starch is
converted into dextrose, after which the excess acid is neutralized with
sodium carbonate. The sirup is then filtered and finally run thru bone
charcoal to remove the last traces of sediment and color. After the final
filtration over the bone charcoal, the clarified liquor is condensed in
vacuum evaporators until it has a Baume of 40° to 50°.
The concentrated sugar liquor is conducted into large cylindrical
crystallizers, where it is slowly agitated for 90 to 100 hours, during which
time the crystallization takes place. The heavy liquor containing the
380 BULLETIN No. 452
crystals of pure dextrose is then run into centrifugal machines which
separate the crystals from the uncrystallized liquor. While still in the
centrifugal the crystals are washed with pure water until nothing remains
but the crystallized dextrose. It is then taken to the rotary air dryers
where the excess moisture is removed, after which it is screened and
bagged. Hydrous dextrose contains approximately 92 percent dry matter.
Anhydrous dextrose is made by redissolving hydrous dextrose and re-
crystallizing as above. By this method a product of higher purity is
obtained and the finished crystals are dried until they are practically free
from moisture.
Dextrose is a different type of sugar from cane sugar, being a mono-
saccharid whereas sucrose is a disaccharid. Dextrose crystallizes more
slowly than cane sugar, and it may form different types of crystals. It is
slightly less sweet than cane sugar and exerts greater osmotic pressure.
It is used extensively in the different food industries, especially in. the
bread, cake, confectionery, carbonated beverage, and dairy manufacturing
trades. Its use in ice cream has been advocated on the basis that it prevents
oversweetness,7* produces a creamier texture, and adds to the sensation of
coolness that is expected in ice cream.
As to nutritional value, dextrose is more easily and quickly assimilated
by the body than is cane sugar, which must be converted into dextrose and
fructose before assimilation can take place. The medical profession in
general advocates the use of dextrose in infant feeding, for counteracting
insulin shock in diabetes, in the treatment of obesity, and to keep the supply
of blood sugar at the proper level for people whose work or play requires
unusual exertion.
50SO— 3-39— 15816
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