AU J.T. 12(2): 81-85 (Oct. 2008)
Effect of Combined Stabilizers Containing Konjac Flour and
κ-Carrageenan on Ice Cream
Adisak Akesowan
School of Science, University of the Thai Chamber of Commerce
Bangkok, Thailand
Email: <adisak_ake@utcc.ac.th>
Abstract
This study was aimed to investigate on physical and sensory properties of ice
cream samples prepared with combined stabilizers including konjac flour and κcarrageenan levels and to determine the suitability of stabilizer combination that could
produce the best quality ice cream. The addition of combined stabilizers made ice
cream samples more hard and viscous than the control sample and also retarded
meltdown properties. The ice cream prepared with 0.3% konjac flour alone exhibited
higher viscosity than those prepared with any levels of combined stabilizers. Based on
sensory test, the optimum combined stabilizer containing 0.27% konjac flour and 0.03%
κ-carrageenan produced the ice cream which was rated for smoothness and iciness
scores (p > 0.05) similar to the control ice cream.
Keywords: Ice cream, konjac flour, κ-carrageenan, stabilizer.
not exceeding 0.5-1.0%, depending on types of
ice cream.
Konjac flour, a neutral polysaccharide
from the tuber of Amorphophallus konjac
C.Koch. and A. oncophallus, is composed of
D-glucose and D-mannose joined by βglycosidic linkage (Thomas, 1997). Konjac
flour is generally recognized as safe (GRAS)
which has special properties as thickening,
gelling, texturizing and water binding. It can be
used to provide fat replacement properties in
fat-free and low-fat bakery and meat products
(Tye, 1991; Akesowan, 2002; Huang and Lin,
2004). There are various grades of konjac flour
sold in the food market; for example, the food
grade konjac flour can be purchase about 400450 baht/kg (Thai Food and Chemical
Company 2008).
Effort was made to find an alternative for
konjac flour application. The use of konjac
flour as a stabilizer in ice cream was created
not only to investigate on quality of ice cream,
but also to reduce the cost of ingredient.
Therefore, the objective of this study was to
determine the effect of combined stabilizers
containing various konjac flour and κ-
Introduction
Ice cream is one of dairy-based frozen
product which generally contains fat, sugar,
nonfat milk solid, flavors and stabilizers.
Regardless of its taste, the quality of ice cream
is evaluated by its structure, texture and
resistence to melting. Stabilizers, usually used
in combination of 2-3 gums, are applied in ice
cream production in order to give positive
effect on the viscosity of the mix, overcome ice
crystals formation during processing and
storage and preserve the structure by slowing
down melting at the consumption stage
(Crichett and Flack 1977). One of primary
stabilizers used in ice cream manufacture is locust
bean gum, which is derived from the seed of
the leguminous carob tree (Ceretonia siliqua)
grown in Mediterranean countries (Glicksman
1969). This gum is a relatively expensive
stabilizer which costs about 2,000-2,500
baht/kg (Thai Food and Chemical Company
2008). Another hydrocolloid, κ-carrageenan is
also used together with locust bean gum as a
secondary stabilizer in order to prevent
wheying-off in ice cream (Stanley 1990). The
amount of stabilizers and/or emulsifiers used is
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AU J.T. 12(2): 81-85 (Oct. 2008)
carrageenan levels on physical and sensory
properties of ice cream.
Ice cream Preparation
Whole milk and whipping cream were
mixed and heated up to 40ºC before adding dry
ingredients (skimmed milk powder, sugar,
stabilizer) according to the formulations shown
in Table 1. Ice cream mixes were pasteurized at
68.3ºC for 15 min, homogenized through a
Waring blender® for 2 min, cooled to 4ºC and
stored for processing the next day. Prior to
freezing, vanilla flavor was added. The aged
mixes were frozen in a bench-top ice cream
maker for 25-30 min. The ice cream sample
were frozen in an air blast freezer at -35ºC for
6 hr, and stored at -18ºC throughout physical
and sensory analysis.
Materials and Methods
Materials
The ingredients used in this work
including whole milk, whipping cream,
skimmed milk powder, vanilla flavor and sugar,
were purchased from a local supermarket. Food
grade hydrocolloids; konjac flour and κcarrageenan, were obtained from Thai Food
and Chemical Co., Ltd. A commercial
stabilizer ‘Supergel-IC®’ was obtained from
Wandermin Food and Chemical Co., Ltd.
Table 1. Ice cream mix formulations.
Ingredients
Whole milk
Whipping cream
Skimmed milk powder
Sugar
Supergel-IC®*
Konjac flour
κ-Carrageenan
Vanilla flavor
Control
43
39
4.6
13
0.3
0.1
Amount (g 100g-1)
Sample
Sample
Sample
1
2
3
43
43
43
39
39
39
4.6
4.6
4.6
13
13
13
0.3
0.27
0.24
0.03
0.06
0.1
0.1
0.1
Sample
4
43
39
4.6
13
0.21
0.09
0.1
* A commercial stabilizer contained carrageenan, locust bean gum and guar gum.
Physical Analysis
Ice cream samples were measured for pH
using a pH-meter (Model 320, Mettler-Toledo
Ltd., Essex, UK). Overrun was estimated using a
standard 100 ml cup, according to the equation as
follows:
% Overrun =
Volume of ice cream - Volume of mix
× 100 .
Volume of mix
Melting property was analyzed at 25 +
2ºC. Hardened ice cream (25 g, -18ºC) was
placed on a sieve (2 mm wide, square openings).
The volume of the melted ice cream at the first
10-min was recorded and further measured at
every 5 min until the time of 40 min was
reached.
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Hardness measurement was obtained
using a penetrometer (StanHope-Seta MK VI,
USA) with a needle-test cell. The time for each
measurement was set up to 10 seconds and the
temperature of the ice cream samples was about
-9 + 1ºC.
Viscosity measurement of ice cream
which filled in 180-ml containers (6 cm
diameter × 9 cm height), was taken at 6 + 1ºC
with a Brookfield viscometer (Model RVDVII,
Brookfield Engineering Laboratories, Inc., MA,
USA). The viscometer was operated at 20 rpm
(spindle number 4).
Sensory Evaluation
A 13-cm unstructured line scale test (0 =
none, 10 = strong) was used to evaluate ice
AU J.T. 12(2): 81-85 (Oct. 2008)
cream attributes for smoothness, gumminess
and iciness. Panelists (ten judges) at University
of the Thai Chamber of Commerce (UTCC) were
semitrained before initiation in the experiment
to be familiar with attributes of ice cream
samples. All testing sessions were held in a
sensory evaluation laboratory with partitioned
booth at UTCC. Distilled water was provided to
rinse their palates between samples (Lawless
and Heymann 1998).
viscosity than other products. The ice cream
prepared with konjac flour alone exhibited the
most viscosity. The konjac flour and κcarrageenan
combination
significantly
increased the viscosity of the ice cream
compared to the use of Supergel-IC® as the
stabilizer. Decreasing konjac flour levels
resulted in lower viscosity, which were because
of higher content of κ-carrageenan, which gives
lower viscosity than konjac flour at the same
concentration. Therefore, the lowest viscosity
was noted for ice cream prepared with a
combined stabilizer including 0.21% konjac
flour and 0.09% κ-carrageenan.
Hardness of ice cream, which expressed
as the distance penetrated into an ice cream; the
shorter the penetrated distance the higher the
hardness value, tended to increase when the
proportion of konjac flour and κ-carrageenan
was varied from 0.3 : 0 to 0.21 : 0.09 in relation
to the control. This may be due to the influence
of κ-carrageenan which is able to interact with
κ-casein and other substances in milk to give
superior properties being promote weak gel
formation in ice cream (Nussinovitch 1997).
This may be explained as to why the more
amount of κ-carrageenan used resulted in
higher hardness of ice cream obtained.
Statistical Analysis
The statistical design for physical
properties was a completely randomized design
(CRD), while sensory data conducted on
randomized complete block design (RCBD). Data
were subject to analysis of variance (ANOVA)
using SPSS for Window version 11.0.
Significant differences between means were
determined using Duncan’s new multiple range
test at p < 0.05 (Cochran and Cox 1992).
Results and Discussion
Results of physical properties of all ice
cream formulations are given in Table 2 and Fig.
1. There was no significant difference (p > 0.05)
in pH-values among all ice cream samples.
Control ice cream had significantly lower
Table 2. Physical properties of ice cream formulations
Combined stabilizer
(konjac flour : κ-carrageenan)
(% by weight)
Control*
0.3 : 0
0.27 : 0.03
0.24 : 0.06
0.21 : 0.09
pHns
6.27
6.20
6.30
6.21
6.23
Viscosity
(× 103 cps)
0.72a
4.32d
2.06c
1.80c
1.34b
Hardness
(mm/10)
163.11c
143.00b
135.00b
71.34a
86.33a
Overrun
(%)
7.08b
2.11a
8.85d
7.89c
2.10a
a, b, c, d
Means in the same column with different superscripts are different (p < 0.05).
*Control = an ice cream prepared with a commercial stabilizer (0.3% Supergle – IC®).
ns
= non-significant.
carrageenan exhibited the ice cream sample
with highest overrun in this study.
As shown in Fig. 1, the use of konjac
flour alone or combined with κ-carrageenan
retarded the meltdown of ice cream samples
with respect to the control. For first 10-min
time interval, the amount of melted ice cream
The addition of combined stabilizers to
the ice cream mixes significantly affected the
overrun of ice cream samples (Table 2). When
the konjac flour was applied alone, the lowest
overrun was observed. The combined stabilizer
including 0.27% konjac flour and 0.03% κRegular Paper
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AU J.T. 12(2): 81-85 (Oct. 2008)
collected for the control was 9 ml as compared
with those of other samples which were less
than 3 ml. After 40-min invertal, the melting
down graph of ice cream prepared with a
combined stabilizer containing 0.27% konjac
flour and 0.03% κ-carrageenan was similar to
that found in the control ice cream made with
Supergel-IC®.
26
สูตรค วบคุม
Control
24
Sample
สูตรที่ 1 1
22
Melted ice cream (ml)
สูตรที่ 2
20
สูตรที่ 3
18
สูตรที่ 4
16
Sample 2
14
12
Sample 3
10
8
6
Sample 4
4
2
0
0
5
10
15
20
Time (min)
25
30
35
40
Control = ice cream prepared with 0.3% commercial stabilizer.
Sample 1 = ice cream prepared with 0.3% konjac flour alone.
Sample 2 = ice cream prepared with 0.27% konjac flour and 0.03% κ-carrageenan.
Sample 3 = ice cream prepared with 0.24% konjac flour and 0.06% κ-carrageenan.
Sample 4 = ice cream prepared with 0.21% konjac flour and 0.09% κ-carrageenan.
Fig. 1. Melting properties of ice cream samples.
those of the control. On the other hand, the
score of iciness tended to decrease. This result
implied that combined stabilizers made ice
cream more smooth, viscous texture and less
ice crystal in the products. However, the
optimum combined stabilizer containing
0.27%konjac flour and 0.03% κ-carrageenan
can be used in ice cream production without
any body and texture defect with respect to that
of the control.
Sensory Evaluation
Sensory attributes of all ice cream
formulations were significantly affected (p <
0.05) by the variation of konjac flour and κcarrageenan levels, as evidence in Table 3. As
the konjac flour and κ-carrageenan ratio was
varied from 0.3:0 to 0.21:0.09, panelists gave
significantly higher scores for smoothness and
gumminess of ice cream samples in relation to
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AU J.T. 12(2): 81-85 (Oct. 2008)
Table 3. Sensory scores of ice cream formulations.
Combined stabilizer
(konjac flour : κ-carrageenan)
(% by weight)
Control*
0.3 : 0
0.27 : 0.03
0.24 : 0.06
0.21 : 0.09
Sensory scores**
Smoothness
5.00a
5.86ab
6.18ab
7.15b
6.25ab
Gumminess
3.07a
6.40c
5.26b
6.50c
5.38bc
Iciness
4.94c
4.57bc
4.82c
3.17ab
2.73a
a, b, c
Means in the same column with different superscripts are different (p < 0.05).
* Control = ice cream prepared with a commercial stabilizer (0.3% Supergel-IC®).
** Based on a 13-cm unstructured line scale test (0 = none, 10 = strong).
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Agri. 30: 1085-9.
Glicksman, M. 1969. Gum technology in the
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Huang, H.Y.; and Lin, K.W. 2004. Influence of
pH and added gums on the properties of
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Lawless, H.T.; and Heymann, H. 1998.
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A.
1997.
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applications.
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Academic
&
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Conclusion
A combined stabilizer containing konjac
flour and κ-carrageenan were successfully
substituted for a commercial stabilizer in ice
cream production. The addition of various
combined stabilizers resulted in higher hard
texture and lower meltdown properties of ice
cream samples. As comparison with the control
sample, the ice cream containing 0.27% konjac
flour and 0.03% κ-carrageenan showed similar
sensory attributes, but more viscous. Further
research is needed to investigate on quality and
ice crystrallization of ice cream prepared with
this combined stabilizer after storage.
References
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Cochran, W.G.; and Cox, G.M. 1992.
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Crichett, N.; and Flack, F.A. 1977. The use of
emulsifying and stabilizing agents in the
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