Heat, Mass Transfer and Physical Properties of Biscuits Enriched with...

Journal of Applied Sciences Research, 6(11): 1680-1686, 2010
© 2010, INSInet Publication
Heat, Mass Transfer and Physical Properties of Biscuits Enriched with Date Powder
1
Fahloul D., 1Abdedaim M. and 2Trystram G.
1
2
Department of Food Engineering, University of Batna, Batna 05000, Algeria
AgroParisTech – Site de Massy,1 avenue des Olympiades, 912744, Massy, France
Abstract: Based on the high composition of date in sugar, sucrose was replaced by date powder at 0%,
20%, 40% and 60% incorporation levels in biscuits baked at three baking temperatures (160, 180 and 200
°C). Biscuits were evaluated for online temperature and moisture content profiles, final water activity,
color and hardness. It was found that date powder replacement did not affect biscuit temperature and
moisture content profiles. However, baking temperature had a clear effect. As date powder level increased,
biscuits had darker color, L-values decreased, a-values increased and b-values were not affected. For
baking temperatures greater than 160 °C, it was found that biscuit final water activity increased as date
powder level increased. Results showed that there is a clear evidence of sucrose substitution on biscuit
texture, as date powder level increased, biscuit hardness decreased.
Key words: Biscuit, Date powder, Sucrose replacement, Color, Hardness.
INTRODUCTION
Biscuits are worldwide food products. Their
popularity is due to their taste, easy consumption, and
long term preservation[1]. Ingredients replacement have
been carried out successfully in order to reduce sugar
or fat levels or to meet consumer demand. Sucrose was
replaced with raftilose in short dough biscuit[2]. The
influence of sugar type and baking temperature on
sugar degradation, furfural and acrylamide formation
were studied[3-5]. Changes in the rheological properties
of the dough and biscuit quality due to fat reduction or
microencapsulation were investigated[6-8].
In recent years, many research works were carried
out to make functional biscuits, by studying the effect
of new ingredients on the nutritional, rheological, and
organoleptic characteristics of biscuits. New ingredients
included products such as black gram[9], fenugreek
flour[10], mustard flour[11], soy flour[1], fibres from
different cereals and fruits[6,12] or some plant extracts
with antioxidant activity[13-14].
Date (Phoenix dactylifera) is a highly energetic
fruit[15]. Typically date contains carbohydrate (44-88%),
fat (0.2-0.5%), protein (2.3-5.6%), dietary fiber (6.411.5%), minerals such as potassium (650 mg/100g),
iron (3 mg/100 g) and magnesium (75 mg/100 g) and
vitamins such as vitamin B1, B2, A, riboflavin and
niacin[16-17]. The antioxidant potentials of dates have
been also demonstrated[18-19]. Date pasta is widely used
to prepare traditional biscuits such as makroud in north
africa and maamoul in the middle east. Based on the
nutritional composition of date, we attempted to replace
sucrose with date powder. However, information on
incorporation of date powder in bakery products is
scarce.
The objectives of this work were to study the
effect of date powder substitution to sucrose on biscuit
quality baked at three baking temperatures by
measuring online product temperature and moisture
content profiles, and to determine biscuit quality by
measuring its final color, water activity and hardness.
MATERIALS AND METHODS
Materials: Commercial wheat flour (Sim brand, Blida,
Algeria) was used in the study, commercially available
sugar, butter and eggs were procured from the local
market. Dry type dates (var. Mech degla) from Biskra
– Algeria, were washed with water, pitted, then cut
into small pieces and air dried at 70 °C in an oven
drier (Memmert type) for 24 h to reach a final
moisture content of around 6%. The dried dates were
powdered using a traditional blender for spices and
stored in a polypropylene bag.
Baking of Biscuits: Biscuits were prepared from wheat
flour (50%), butter (30%), sucrose (15%) and eggs
(5%). Blends of 0%, 20%, 40%, 60% were prepared
by replacing sucrose with date powder (Control, D20%,
D40%, D60%). The ingredients were mixed manually
for 5 min in a plastic bawl to obtain a homogeneous
dough. Biscuit pieces were cut into circular shapes
Corresponding Author: Fahloul D., Department of Food Engineering, University of Batna, Batna 05000, Algeria
E-mail:[email protected]
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J. Appl. Sci. Res., 6(11): 1680-1686, 2010
using a biscuit press (Ampia biscuits, Italy). Biscuits
were baked in an oven (SPAG, Massy, France) set at
160, 180 and 200 °C. Baking process ended when the
final moisture content of biscuits reached 0.05 (kg
water/kg dry basis (db)). Final water content or
browning are commonly used to determine the end of
the baking process[20]. After cooling to room
temperature for 30 min, biscuits were packed in
polyethylene pouches for further analysis.
Analysis: Biscuit temperature was measured during
baking using a K-type thermocouple placed horizontally
in the centre of the biscuit and directly connected to a
computer to allow online monitoring. Data were
recorded every 9 s.
Water content was calculated by measuring biscuits
weight during baking with a balance (Sartorius-IB 12
EDE-P, France) connected directly to the oven (SPAG,
Massy, France) and to the computer. Data were
recorded every 9 s.
Biscuits samples were ground using a food blender
(Moulinex blender). Five grams of powdered biscuits
were dried in an oven at 105±1 °C for 24 h to obtain
a constant weight. The water activity was measured in
the aw-meter (FA-st lab, GBX, Romans sur Isère,
France) at ambient temperature on biscuits samples.
The color system of L (brightness), a (redness) and
b (yellowness) were measured using a Minolta color
analyzer (Minolta, Carrières sur Seine, France).
Measurements were made on ground biscuits samples
placed in a small bowl with a cover in order to
provide a uniform surface[3].
Hardness of biscuits was carried out on a texture
analyser (Stable Micro Systems, Surrey, UK) using a
cylindrical probe P/2. A crosshead speed of 1 mm/s
with a load cell of 5 kg were used in the study. Biscuit
sample was placed on the platform and the probe was
attached to the crosshead of the instrument. The
absolute peak force from the resulting curve was
considered as the hardness of the biscuit[21].
Experimental data were the average value of
triplicate determinations for each sample. Data were
reported as mean ± SD.
Estimation of the Rate of the Biscuit Temperature
Rise: The rate of temperature rise of the biscuit was
calculated by estimating the following expression :
(1)
where, m is biscuit weight (kg), cp is the specific heat
of biscuit (J/(kg °C)), T is biscuit temperature (°C) and
t is the baking time (s).
The model of Choi and Okos[22] was used to
predict the specific heat based on composition and
temperature. The model is as follows:
(2)
where Xi is the fraction of the ith component, n is the
total number of components in biscuits, and cpi is the
specific heat of the ith component.
RESULTS AND DISCUSSION
Effect of Baking Temperature on Biscuit
Temperature and Moisture Content: The effect of
baking temperature on biscuit temperature is shown in
Fig. 1. At higher baking temperature, biscuit
temperature is higher. Three phases were identified[20].
The first phase is short (1 min) and had a rapid
temperature increase. The second phase had a slower
temperature increase. It ended when biscuit temperature
reached a value around 100 °C. This could be due to
the heat generated by water vapor condensation on
biscuit cold surface[23]. The third phase had a much
slower temperature increase until the end of baking,
where most of the heat was used to evaporate water.
These phases were observed for all substitutions.
The observed three phases were confirmed when
calculating the rate of temperature increase of biscuits.
Fig. 2 shows the rate of temperature rise as a function
of baking time at substitution 20%, (data at
substitutions 40% and 60% were similar but not
shown). It shows the presence of three baking phases.
The first phase is short and characterised by a rapid
increase in the temperature rate. Followed by the
falling rate phase. The third phase is characterised by
the stabilisation of the rate of temperature rise due to
the stabilisation of biscuit temperature.
In fact, phases in the falling rate period are due to
the structural changes occuring during baking[20]. The
calculated specific heat of biscuit using the model of
Choi and Okos[22] was estimated to 1751 (J/kg °C).
This value is similar to the parameters used by
Hadiyanto, Asselman, van Straten, Boom, Esveld and
van Boxtel[24] for biscuit and cake.
The effect of baking temperature on biscuit
moisture content is evident (Fig. 3). The higher the
baking temperature, the faster the moisture content
decrease. Three phases could be identified: latency,
rapid decrease and stabilization phases. These results
were in agreement with previous results for cookies[3]
and bread crust[25]. The first two phases were observed
for all substitutions. The stabilization phase was not
clearly identified because baking time was short.
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J. Appl. Sci. Res., 6(11): 1680-1686, 2010
Fig. 1a: Effect of baking temperature on biscuit temperature at substitution 20%.
Fig. 1b: Effect of baking temperature on biscuit temperature at substitution 40%.
Fig. 2: The rate of biscuit temperature rise at substitution 20%.
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J. Appl. Sci. Res., 6(11): 1680-1686, 2010
Fig. 3a: Effect of baking temperature on biscuit moisture content at substitution 20%.
Fig. 3b: Effect of baking temperature on biscuit moisture content at substitution 40%.
Effect of Sucrose Substitution on Biscuit
Temperature and Moisture Content: Sucrose
substitution with date powder was not found to have
effects on biscuit temperature and moisture content
(Fig. 4-5) (data for baking temperatures of 160 and 200
°C were not shown, but similar to 180 °C). Hence,
biscuit temperature and moisture content profiles were
independent on the type of sugar in the dough[3].
Biscuit Water Activity: Water activity (Aw) values
between biscuits varied significantly (Table 1). Biscuits
with date powder substitution of 60% had the highest
Aw value. Water activity increase was proportional to
sucrose substitution for different baking temperatures
(160, 180 and 200 °C). Except for baking temperature
160 °C, where Aw was higher for substitution (D20%).
Date powder had high dietary fibre, indicating that
formulations with high fibre content had higher water
activity. These results were similar to those obtained by
O’Brien et al.[8], where less protein contents caused
high water activity due to less bound water in the
biscuit.
Biscuit Color: L*a*b Values: The effects of date
powder on color parameter L* of biscuits were shown
in Table 1. All biscuits containing sucrose substitution
gave lower L-values. For all baking temperatures, as
the level of substitution increased, L-values decreased.
The lowest L-value was 61.9 and the highest was 74.5.
Therefore, date powder substitution had a positive
effect on biscuit color[2]. The effects of date powder on
the redness fraction of biscuits color a* were shown in
Table 1. a-values increased as the level of substitution
increased, with values ranging from 0.41 to 6.16.
Therefore, all substitutions increased the redness value
of biscuits. This could be attributed to the brown color
of dates. The effect of sucrose substitution on the
yellowness of the color b* was presented in Table 1.
In general, no evident change in b-value was observed
for different substitutions and baking temperatures.
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Fig. 4: Biscuit temperature for different substitutions at baking temperature 180 °C.
Fig. 5: Biscuit moisture content for different substitutions at baking temperature 180 °C.
Table 1: Biscuit final water activity and color values (L*a*b*) for different substitutions and at different baking temperatures.
Temperature (°C)
Subst. (%)
Water activity
L*
a*
b*
160
0
0.34±0.02
74.5±2.0
0.41±0.14
22.9±1.3
------------------------------------------------------------------------------------------------------------------------------------------------------20
0.40±0.02
68.2±2.8
3.07±0.24
22.3±2.0
------------------------------------------------------------------------------------------------------------------------------------------------------40
0.33±0.01
66.7±1.0
4.62±0.22
23.5±1.0
------------------------------------------------------------------------------------------------------------------------------------------------------60
0.42±0.02
66.7±1.7
4.58±0.54
23.6±0.2
180
0
0.33±0.02
74.2±1.6
1.96±0.53
24.4±0.4
------------------------------------------------------------------------------------------------------------------------------------------------------20
0.36±0.01
70.7±0.5
3.65±0.35
23.7±0.3
------------------------------------------------------------------------------------------------------------------------------------------------------40
0.38±0.02
66.4±1.4
4.99±0.70
23.3±0.2
------------------------------------------------------------------------------------------------------------------------------------------------------60
0.42±0.01
63.2±0.8
6.16±0.41
23.3±0.1
200
0
0.31±0.00
73.3±0.9
2.16±0.38
23.1±0.4
------------------------------------------------------------------------------------------------------------------------------------------------------20
0.35±0.02
66.4±0.3
4.85±0.24
23.2±0.2
------------------------------------------------------------------------------------------------------------------------------------------------------40
0.38±0.02
61.9±0.4
5.80±0.43
22.1±0.2
------------------------------------------------------------------------------------------------------------------------------------------------------60
0.41±0.00
62.4±2.3
5.79±0.74
22.2±0.1
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J. Appl. Sci. Res., 6(11): 1680-1686, 2010
Biscuit Hardness: The effect of sucrose replacement
on biscuit hardness at baking temperature 180 °C was
shown in Fig. 6. Results revealed that increasing date
powder level decreased biscuit hardness. Results varied
from 11.62 N for control biscuits to 6.7 N for biscuits
with the highest date powder replacement. Similar
hardness values were obtained for all tested biscuits
when compared to the literature[11]. This softening
effect was observed by Olinger and Velasco[26] when
substituting sugar with sugar alcohols during biscuit
manufacture and by Gallagher et al.[2] when replacing
sugar with raftilose in short dough biscuit production.
In fact, Biscuit hardening is caused by crystallization
of sugar when the biscuit is cooling[2].
Conclusion: Based on the nutritional composition of
date in sugars, we attempted to replace sucrose with
date powder at 0, 20, 40 and 60% incorporation levels.
The effect of baking temperature on biscuit temperature
and moisture content was evident. Sucrose substitution
with date powder was not found to have effect on
biscuit temperature and moisture content. Biscuits with
date powder substitution of 60% had the highest Aw
value. Water activity increase was proportional to
sucrose substitution for different baking temperatures
(160, 180 and 200 °C), indicating that formulations
with high fibre content had higher water activity. All
biscuits containing sucrose substitution gave lower Lvalues. Date powder substitution had a positive effect
on biscuit color, a-values increased as the level of
substitution increased. In general, no evident change in
b-value was observed for different substitutions and
baking temperatures. Results revealed that increase in
date powder level decreased biscuit hardness. Data
varied from 11.62 N for control biscuits to 6.7 N for
biscuits with the highest date powder replacement of
60%.
Fig. 6: Effect of date powder replacement on biscuit hardness at baking temperature 180 °C.
3.
ACKNOWLEDGMENTS
The authors are grateful to Dr. S. Berland from
AgroParisTech, Massy, France for her excellent
assistance.
REFERENCES
4.
1.
2.
Vitali, D., I. Vedrina Dragojevic and B. Sebecic,
2009. Effects of incorporation of integral raw
materials and dietary fibre on the selected
nutritional and functional properties of biscuits.
Food Chemistry, 114: 1462-1469.
Gallagher, E., C.M. O’Brien, A.G.M. Scannell and
E.K. Arendt, 2003. Evaluation of sugar replacers
in short dough biscuit production. Journal of Food
Engineering, 56: 261-263.
5.
1685
Ait Ameur, L., O. Mathieu, V. Lalanne, G.
Trystram and I. Birlouez-Aragon, 2007.
Comparison of the effects of sucrose and hexose
on furfural formation and browning in cookies
baked at different temperatures. Food Chemistry,
101: 1407-1416.
Gokmen, V., O.C. Acar, H. Koksel and J. Acar,
2007. Effects of dough formula and baking
conditions
on
acrylamide
and
hydroxymethylfurfural formation in cookies. Food
Chemistry, 104: 1136-1142.
Graf, M., T.M. Amrein, S. Graf, R. Szalay, F.
Escher and R. Amado, 2006. Reducing the
acrylamide content of a semi-finished biscuit on
industrial scale. LWT – Food Science and
Technology, 39: 724-728.
J. Appl. Sci. Res., 6(11): 1680-1686, 2010
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Sudha, M.L., A.K. Srivastava, R. Vetrimani and K.
Leelavathi, 2007. Fat replacement in soft dough
biscuits: Its implications on dough rheology and
biscuit quality. Journal of Food Engineering, 80:
922-930.
Agyare, K.K., K. Addo, Y.L. Xiong and C.C.
Akoh, 2005. Effect of structured lipid on
alveograph characteristics, baking and textural
qualities of soft wheat flour. Journal of Cereal
Science, 42: 309-316.
O’Brien, C.M., D. Chapman, D.P. Neville, M.K.
Keogh and E.K. Arendt, 2003. Effect of varying
the microencapsulation process on the functionality
of hydrogenated vegetable fat in shortdough
biscuits. Food Research International, 36: 215-221.
Patel, M.M., and G. Venkateswara Rao, 1995.
Effect of untreated, roasted and germinated black
gram (Phaseolus mungo) flours on the physicochemical and biscuit (cookie) making
characteristics of soft wheat flour. Journal of
Cereal Science, 22: 285-291.
Hooda, S., and S. Jood, 2005. Organoleptic and
nutritional evaluation of wheat biscuits
supplemented with untreated and treated fenugreek
flour. Food Chemistry, 90: 427-435.
Tyagi, S.K., M.R. Manikantan, H.S. Oberoi and G.
Kaur, 2007. Effect of mustard flour incorporation
on nutritional, textural and organoleptic
characteristics of biscuits. Journal of Food
Engineering, 80: 1043-1050.
Bilgicli, N., S. Ibanoglu and E.N. Herken, 2007.
Effect of dietary fibre addition on the selected
nutritional properties of cookies. Journal of Food
Engineering, 78: 86-89.
Ajila, C.M., K. Leelavathi and U.J.S. Prasada Rao,
2008. Improvement of dietary fiber content and
antioxidant properties in soft dough biscuits with
the incorporation of mango peel powder. Journal
of Cereal Science, 48: 319-326.
Reddy, V., A. Urooj and A. Kumar, 2005.
Evaluation of antioxidant activity of some plant
extracts and their application in biscuits. Food
Chemistry, 90: 317-321.
Ismail, B., I. Haffar, R. Baalbaki and J. Henry,
2008. Physico-chemical characteristics and sensory
quality of two date varieties under commercial and
industrial storage conditions. LWT – Food Science
and Technology, 41: 896-904.
16. Al-Shahib, W., and R.J. Marshal, 2003. The fruit
of the date palm: its possible use as the best food
for the future. International Journal of Food
Science and Nutrition, 54: 247-259.
17. Dukan, P., 1998. Dictionnaire de diététique et de
nutrition. Le cherche midi editor, Paris.
18. Biglari, F., A.F.M. Alkarkhi and A.M. Easa, 2008.
Antioxidant activity and phenolic content of
various date palm (Phoenix dactylifera) fruits from
Iran. Food Chemistry, 107: 1636-1641.
19. Mansouri, A., G. Embarek, E. Kokkalou and P.
Kefalas, 2005. Phenolic profile and antioxidant
activity of the Algerian ripe date palm fruit
(Phoenix dactylifera). Food Chemistry, 89: 411420.
20. Chevallier, S., P. Colonna and G. Della Valle,
2000. Contribution of major ingredients during
baking of biscuits dough systems. Journal of
Cereal Science, 31: 241-252.
21. Bourne, M., 2002. Food texture and viscosity:
concept and measurement. Academic Press Inc,
New York.
22. Choi, Y. and M.R. Okos, 1986. Effects of
temperature and composition on the thermal
properties of food. In Food engineering and
process applications, Vol. 1. Transport Phenomena,
Eds., M. Le Maguer and P. Jelen, Elsevier Applied
Science Publishers, London.
23. Chevallier, S., G. Della Valle, P. Colonna, B.
Broyart and G. Trystram, 2002. Structural and
chemical modifications of short dough during
baking. Journal of Cereal Science, 35: 1-10.
24. Hadiyanto, A. Asselman, G. van Straten, R.M.
Boom, D.C. Esveld and A.J.B. van Boxtel, 2007.
Quality prediction of bakery products in the initial
phase of process design. Innovative Food Science
and Emerging Technologies, 8: 285-298.
25. Sablani, S.S., M. Marcotte, O.D. Baik and F.
Castaigne, 1998. Modeling of simultaneous heat
and mass transport in the baking process. LWT –
Food Science and Technology, 31: 201-209.
26. Olinger, P.M. and V.S. Velasco, 1991.
Opportunities and advantages of sugar replacement.
Cereal Foods World, 41(3): 110-117.
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