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LWT - Food Science and Technology
journal homepage: www.elsevier.com/locate/lwt
Optimization of the gelatinization conditions to improve the expansion and
crispiness of fish crackers using RSM
Reshma Ramesha
, R. Jeya Shakilab,∗
, B. Sivaramanb
, P. Ganesana
, P. Velayuthama
a
Department of Fish Processing Technology, School of Harvest and Post Harvest Technology, Fisheries College and Research Institute, Thoothukudi 628008, India
b
Department of Fish Quality Assurance and Management, School of Harvest and Post Harvest Technology, Fisheries College and Research Institute, Thoothukudi 628008,
India
A R T I C L E I N F O
Keywords:
Fish crackers
Linear expansion
Crispiness
RSM
A B S T R A C T
Fish crackers were prepared by blending lean fish (Nemipterus japonicus) along with tapioca, corn and sago in the
proportion 40:60 (cooked fish: starch) to optimize the gelatinization conditions in order to improve the ex-
pansion and crispiness using Response Surface Methodology (RSM). The process variables were steaming time
(20, 40, 60 min), gel setting time (12, 18, 24 h) and drying temperature (40, 50, 60 °C). The responses taken
were linear expansion, bulk density and crispiness. The average values ranged from 51.295 to 71.135% for linear
expansion, 0.241–0.4 g/cm3
; for bulk density and 2.710–9.011 N (hardness value) for crispiness of the products.
The optimum condition predicted by RSM to have high linear expansion of products was at a steaming time of
40 min, a gel setting time of 24 h and a drying temperature of 40 °C. To have a maximum crispiness, the steaming
time has to be increased as 60 min. This study enabled to optimize few important process conditions that are not
examined earlier to improve the expansion and crispiness of the fish crackers.
1. Introduction
Fish being easily digestible provides a good balance of proteins,
vitamins and minerals with relatively low calorie content; and possesses
several functional properties. Considering the nutritional value of fish,
snack food products are now gaining importance in day-to-day life due
to their high acceptability and the capability to satisfy the occasional
pangs of hunger (Kumar, Goswami, Pathak, & Singh, 2012). Fish
crackers are the popular snack food in many South East Asian countries
(Kyaw, Yu, Cheow, Dzulkifly, Howell, 2001a; Kyaw, Cheow, Yu,
Dzulkifly, 2001b) and are known by different names such as Keropok in
Malaysia, Kerupuk in Indonesia, Kaew krab pla in Thailand and Banh
phongtom in Vietnam. They are prepared by blending fish flesh with
starch and water; and then shaping into round, oblique, stick or long-
itudinal forms followed by boiling or steaming for gelatinization (Chng
and Kuang, 1991). The gelatinized product is then cooled, sliced into
different shapes and dried until the moisture content reaches around
10%. Fish crackers are generally eaten as a snack food or can be taken
together with other main dishes.
As, traditionally fish crackers are prepared in a small scale as a
cottage industry, they lack proper expansion, shape and thickness.
Hence, the factors that influence the degree of linear expansion need to
be optimised to produce fish crackers in a large scale. Various kinds of
starch flour such as tapioca, wheat, corn, sago, rice etc. are generally
used for making fish crackers. Tapioca flour is known to produce the
best fish crackers with excellent expansion properties (Mohamed,
Abdullah, & Muthu, 1989; Tongdang, Meenun, & Chainui, 2008; Yu,
1991). The amylopectin content in the starch flour largely influence the
linear expansion property (Mohamed et al., 1989). Marine fishes such
as sardine (Yu, 1991), jew fish (Kyaw et al., 2001a,b), big eye (King,
2002), snapper, conger, feather back (Peranginangin, Fawzya,
Sugiyono, & Muljanah, 1996), trevally, wolf herring and round herring
are generally used for fish cracker preparation in South East Asia.
Gelatinization of starch plays a major role in determining the final
quality characteristics of the snack products (Beleia, Butarelo, & Silva,
2006). The most important sensory characteristic preferred by con-
sumers is the crispiness/crunchiness of the snack product (Luyten,
Plijter, & Van Vliet, 2004). The fish crackers with high linear expansion
are most preferred, as it is related to the crispness of the product. The
degree of linear expansion is therefore an important quality parameter
used to examine the crackers (Yu, 1991). A linear expansion greater
than 77% is required for an acceptable level of crispness (Siaw,
Idrus, & Yu, 1985). Bulk density is also taken as another index of the
extent of puffing that considers expansion in all directions.
Crispiness is an important and unique parameter to be controlled in
deep-fat fried products (Pedreschi & Moyano, 2005; Thanatuksorn,
http://dx.doi.org/10.1016/j.lwt.2017.10.045
Received 23 March 2017; Received in revised form 12 September 2017; Accepted 20 October 2017
∗
Corresponding author.
E-mail address: jeyashakila@gmail.com (R. Jeya Shakila).
LWT - Food Science and Technology 89 (2018) 248–254
Available online 23 October 2017
0023-6438/ © 2017 Elsevier Ltd. All rights reserved.
T

2. Kajiwara, & Suzuki, 2007). It is being related to the cellular structure of
foods (Barrett, Cardrello, Lesher, & Taub, 1994; Bouvier,
Bonneville, & Goullieux, 1997; Gao & Tan, 1996; Mohamed,
Jowitt, & Brennan, 1982; Stanley & Tung, 1976; Vickers & Bourne,
1976). It is characterised by brittle fracture force and distinguishable
fracture events. The emission of sound is an important aspect for the
perception of crispness and crunchiness (Drake, 1963; Luyten et al.,
2004; Van Vliet, Visser, & Luyten, 2007; Vickers & Bourne, 1976).
Food Scientists have undertaken research to improve the degree of
expansion and crispness of crackers with the incorporation of food
additives such as sodium pyrophosphate and sodium bicarbonate
(Peranginangin et al., 1996), optimization of steaming time (Cheow,
Yu, & Howell, 1999; Kyaw, Yu, Cheow, & Dzulkifly, 1999), thickness
(Peranginangin et al., 1996) and ratio of fish to starch (King, 2002).
However, there are no reports on the influence of the gel setting time
and drying temperature on the linear expansion of the product. Hence
apart from the raw material and other ingredients used for preparing
fish crackers, steaming time, gel setting time and drying temperature
are the important processing parameters that have to be optimised to
scale – up the process. In this study, a marine fish (Nemipterus japonicus)
was used to prepare fish crackers along with tapioca, corn and sago
flour at a fixed proportion and a Response Surface Methodology (RSM)
was adopted to optimize the gelatinization condition in relation with
steaming time, gel setting time and drying temperature in order to have
maximum linear expansion, crispiness and a better bulk density of the
snack product.
2. Materials and methods
2.1. Materials
Fresh fish (Nemipterus japonicus) was purchased from the local fish
market of Tuticorin, India and brought to the laboratory in iced con-
dition for processing. Fish was semi-dressed by removing the head,
viscera, fins and tail. Tapioca flour, corn flour, sago flour and other
ingredients were obtained from the local supermarket. Refined sun-
flower oil was also purchased from the local shop.
2.2. Preparation of fish crackers
Semi-dressed fish was steamed at 100 °C for 10 min and the meat
was picked out manually. Fish crackers were prepared using steamed
fish meat, tapioca, corn and sago flour at the ratio of 4:3:1.5:1.5. Other
ingredients used for the preparation were salt (2%), turmeric (1%),
garam masala (3%), and pepper (1%) to improve the flavour and taste
in addition to the water used for dough formation. The percentage of
the ingredients was based on the weight of the fish and starch. All the
ingredients were blended using a food processor (BRAUN, Germany) for
2–3 min until dough is formed. The dough was then rolled into cy-
lindrical shape and steamed for gelatinization. The steamed roll was
cooled and allowed to set at 4 °C. The hardened roll was then cut into
round slices of 2 mm thickness using a hand slicer (ANJALI, India),
dried in an oven (TECHNICO, Chennai, India) and finally fried in
sunflower cooking oil at 180–200 °C for 1 min in a shallow pan.
2.3. Optimization of processing conditions by RSM
To optimize the steaming time, gel setting time and drying tem-
perature of fish crackers, Box-Behnken Design of Response Surface
Methodology (RSM) was used in this study (Ferreira et al., 2007). Three
levels of steaming time (A), gel setting time (B) and drying temperature
(C) were selected. Based on the previous experiments conducted in our
laboratory, the steaming time of 40 min, the gel setting time of 18 h and
the drying temperature of 50 °C were chosen as the centre points. Linear
expansion, bulk density and crispiness were taken as output variables.
The coded values and corresponding values of the independent
variables are given in Table 1. The Design Expert 7.0 software was used
to obtain Box- Behnken quadratic design model, which gave 17 runs to
perform the analysis. Response surface and contour plots were gener-
ated using Design Expert 7 software (Richard Boxton, 2007).
2.4. Linear expansion
The linear expansion of the fish crackers was determined in tripli-
cate based on the method by Yu (1991). The dried fish crackers was
marked with three lines across using a permanent marker pen (Camlin,
Kokuyo Camlin Ltd., India) and the lines were measured before and
after frying in oil at 180–200 °C. The percentage linear expansion was
calculated as follows:
=
−
×
Linear expansion (%)
Length after frying Length before frying
Length before frying
100
2.5. Bulk density
The volume of the fish crackers was determined in triplicate using
sesame seed displacement method described by Sahin and Sumnu
(2006). The experiment is carried out in a beaker of known volume. The
fried crackers are placed inside the beaker and the beaker was filled
with the sesame seed. Later the crackers are taken out from the beaker.
The decrease in the volume after the fried ones were taken out gave the
volume of the fried crackers. The weight was determined using an
electronic balance. The bulk density (p) was calculated as:
=Bulk density (ρ)
Mass of the fish cracker (m)
Volume of the cracker (v)
2.6. Crispiness
A texture analyser (LLOYD Instruments, England) equipped with a
spherical probe of diameter 7 mm was used to determine the crispiness
of the fried fish crackers (n = 6). The trigger and speed of the probe
was set at 0.05N and 10 mm/min, respectively. The dried slices were
fried in oil and the fried crackers were put above a support rig and
penetrated using the spherical probe. The hardness value was given in
terms of Newton (N), which is an inverse of crispiness.
2.7. Statistical analysis
Data was analysed using response surface methodology (Design
Expert 7.0 software). Analysis of variance was performed for the re-
sponse surface quadratic model and the model F value of 5.96 implied
that the model was significant. The model terms were significant at
p < 0.05.
Table 1
Experimental design for optimization of three process parameters.
Parameters Codes Codes
−1 0 1
A (Steaming time, min) 20 40 60 20 40 60
B (Gel setting time, h) 12 18 24 12 18 24
C (Drying temperature, °C) 40 50 60 40 50 60
R. Ramesh et al. LWT - Food Science and Technology 89 (2018) 248–254
249

3. 3. Results and discussions
3.1. Effect of steaming time, gel setting time and drying temperature on the
linear expansion
Fish crackers expand into porous snack product during frying and
the degree of expansion is measured as linear expansion. The rapid
increase in molecular volume of water during evaporation is the con-
cept during expansion of fried foods (Rossell, 2001, pp. 115–336). The
results for linear expansion of fish crackers processed at selected pro-
cess conditions are presented in Fig. 1(a–c). Linear expansion of fish
crackers showed significant variation between steaming times of
20–40 min (p < 0.05) at the drying temperature of 40 °C (Fig. 1a).
Earlier, Kyaw et al. (1999) found that Keropok gel required a steaming
time of 20–30 min for sufficient cooking to get better linear expansion
and harder texture of gel. Similarly, ‘Khao Kriap Waue’, a Thai based
snack, required a steaming time of 20 min for complete gelatinization of
the dough (Jomduang & Mohamed, 1994). During steaming, the starch
granules expand to their maximum size before fragmentation. Swelling
or expansion of the starch molecules is due to the hydration of water
molecules (Leach, McCowen, & Schoch, 1959). When the swelling
power increases greater amount of water will be entrapped in starch
granule that contributes to higher linear expansion upon frying (Cheow,
Kyaw, Howell, & Dzulkifly, 2004). In this study, the linear expansion
was good at the steaming times of 40 and 60 min. The gelatinization
temperature of tapioca starch ranges between 52 and 64 °C (Pomeranz,
1991). So, degree of gelatinization of the starch is one of the factors
influencing the degree of linear expansion of snack products when
immersed in hot oil (Lachmann, 1969, p. 143) and the reduced ex-
pansion is mainly due to incomplete gelatinization (Mohamed et al.,
1989). According to Kyaw et al. (1999), with a steaming time of 20 min,
the centre of keropok gel had acquired around 92 °C. This study in-
dicated that a minimum steaming time of 40 min was sufficient to cause
complete gelatinization of starch, to bring maximum expansion of fish
crackers.
The linear expansion of the fish crackers showed significant differ-
ence at the drying temperatures of 40 °C and 50 °C (p < 0.05), irre-
spective of steaming and gel setting times. It is noted that the linear
expansion decreased at higher drying temperature (Fig. 1a). A low
drying temperature of 40–50 °C is more preferred to prevent case
hardening of the dried product (Siaw et al., 1985), which otherwise
leads to the poor expansion of the final product, as observed in this
study.
There is significant difference in the linear expansion of fish cracker
at higher gel setting times i.e. between 18 and 24 h (p < 0.05), irre-
spective of drying temperature (Fig. 1b). This means that a higher gel
setting time provided more linear expansion in the fried fish crackers.
Even though gelatinization happens during the steaming process; the
gel has to be perfectly set to form a hardened structure by storing in
chilled condition for an appropriate duration. ‘Retrogradation’ of
cooked starch will occurs at the time of chilling, which is a reaction that
takes place when the amylose and amylopectin chains are steamed and
Fig. 1. a: The effect of steaming time and drying temperature on linear expansion. b: The effect of gel setting time and steaming time on linear expansion of fried crackers. c: The effect of
drying temperature and gel setting time on linear expansion of fried fish cracker.
R. Ramesh et al. LWT - Food Science and Technology 89 (2018) 248–254
250

4. the gelatinized starch realign themselves on chilling resulting in setting
of gel (Wang, Li, Copeland, Niu, & Wang, 2015). When starch is heated
and dissolved in water, crystalline structure of amylopectin and amy-
lose is lost and then they get hydrated to form a viscous solution. If
viscous solution is further chilled at lower temperature for a long
period, the linear molecules, amylose and linear parts of amylopectin
retrograde and rearrange themselves again to a more crystalline
structure. The crystallization of amylopectin plays a major role in the
firmness of starch gels upon storage (Ring et al., 1987; Wang et al.,
2015). So, starch retrogradation depends upon the duration of chilled
storage. It has been earlier reported that firmness is higher in cracker
gel set for 24 h, as it improved the slicing of the gel, which in turn
influenced the linear expansion of fried crackers. In this study, it was
found that although the steaming time did not influence the gel setting
time, the drying temperature of 40 °C gave maximum linear expansion
at the gel setting time of 24 h (Fig. 1c).
3.2. Effect of steaming time, gel setting time and drying temperature on the
bulk density
Bulk density indicates the expansion of fish crackers on all the di-
rections and it is used as an index of puffing. The volume expansion of
the fried product is greatly influenced by the escape of water during
frying (Rossell, 2001, pp. 115–336). As the volume expands, the density
decreases. The results for bulk density of fish crackers made by the
selected process conditions are presented in Fig. 2a–c. The bulk density
of fish crackers remained unchanged with an increase in drying tem-
perature at a steaming time of 20 min; while at the steaming times of 40
and 60 min, it increased with the drying temperature (Fig. 2a). Bulk
density was found to be minimum at the steaming time of 40 min in fish
crackers at a drying temperature of 40 °C corresponding with the
highest linear expansion. The bulk density was minimum at a gel setting
time of 18 h with a steaming time of 40 min (Fig. 2b). The bulk density
did not increase at a drying temperature of 40 and 50 °C with the in-
crease in gel setting time (Fig. 2c). But, at a drying temperature of
60 °C, it slightly increased with the increase in gel setting time. Also, it
decreased with the increase in gel setting time, irrespective of the in-
crease in steaming time (Fig. 2c). The bulk density was minimum at the
gel setting time of 18 h and drying temperature of 40 °C with a steaming
time of 40 min. The bulk density has a significant negative correlation
to linear expansion (Saeleaw and Schleininga, 2011).
The optimised gel setting time to have the maximum bulk density is
not in accordance with the optimised gel setting time of 24 h required
to have the maximum linear expansion. Badrie and Mellowes (1992)
reported that crude protein of soyabean flour/cassava extrudates cor-
related positively with bulk density and negatively with expansion. The
Fig. 2. a: The effect of steaming time and drying temperature on bulk density. b: The effect of gel setting time and steaming time on bulk density. c: The effect of drying temperature and
gel setting time on bulk density.
R. Ramesh et al. LWT - Food Science and Technology 89 (2018) 248–254
251

5. presence of amylopectin in starch has positively correlated with bulk
density in a Thai rice-based snack, Khao-Kriap-Waue
(Jomduang & Mohamed, 1994). The rapid increase in molecular volume
of water during evaporation causes the expansion of fried foods
(Rossell, 2001, pp. 115–336).
3.3. Effect of steaming time, gel setting time and drying temperature on the
crispiness
Crispiness is one of the quality parameters related to the cellular
structure of the foods. It is measured in terms of hardness (N) by the
texture analyser. Hardness has a negative correlation with crispiness.
Increasing linear expansion will increase the crispiness value of fried
crackers, which is indicated by a lower hardness value (Peranginangin
et al., 1996; Yu, 1991). The results on the crispiness of fish crackers
processed at different combinations of the process conditions are pre-
sented in Fig. 3a–c.
Crispiness of the fried crackers at the drying temperatures of 40 and
50 °C increased with the increase in steaming time but not at the drying
temperature of 60 °C. More crispy crackers were developed at a
steaming time of 60 min at a drying temperature of 40 °C (Fig. 3a). The
crispiness decreased with the increase in drying temperature from 40 to
60 °C, irrespective of the gel setting time. The crispiness of fish crackers
showed a different trend in respect to the increasing gel setting time. At
a gel setting time of 12 h, the crispiness was more, while at 18 h, it was
less and further at 24 h, the crispiness improved, irrespective of the
increase in steaming time (Fig. 3b). The crackers were crispy at a gel
setting time of 24 h and a drying temperature of 40 °C (Fig. 3c). Hence,
it was found that a steaming time of 60 min produced more crispy
Fig. 3. a: The effect of steaming time and drying temperature on crispiness. b: The effect of gel setting time and steaming time on crispiness. c: The effect of drying temperature and gel
setting time on crispiness.
Table 2
The regression coefficients of the quadratic equations for the process parameters.
Factor Regression Coefficient
Linear expansion
(%)
Bulk density (g/
m3
)
Crispiness (N)
Intercept 58.40 0.27 7.81
A –Steaming time 0.18 0.020* −0.74
B –Drying temperature −5.35* 0.021* 0.90*
C –Gel setting time 2.22 −1.875 0.22
AB −2.77 0.036* 0.81
AC 0.29 0.024* −0.27
BC 0.21 −2.750 −0.69
A2
−1.66 0.049* −0.14
B2
4* - 0.16 −1.27*
C2
3.85* 2.975 −1.40*
R2
0.86 0.92 0.84
*Parameter is significant to the regression model.
R. Ramesh et al. LWT - Food Science and Technology 89 (2018) 248–254
252

6. crackers at a drying temperature of 40 °C but at the gel setting times of
12 and 24 h. The optimised steaming time of 60 min in terms of cris-
piness was not in accordance with the optimised steaming time of
40 min in respect to linear expansion of the product.
3.4. Optimization of steaming time, gel setting time and drying temperature
The regression coefficients of quadratic equations for linear ex-
pansion, bulk density and crispiness were analysed by using ANOVA
from Design Expert 7.0 software. The regression coefficient for the
quadratic model is shown in Table 2. Statistical analysis of quadratic
model indicates that p value of the model was < 0.05, which explained
that the model was significant and can be used for optimization of
gelatinization conditions. The linear expansion of fish crackers was
significantly affected by drying temperature and gel setting time
(p < 0.05). The bulk density of fish crackers was however significantly
affected only by the steaming time (p < 0.05). The crispiness of fish
crackers was significantly dependent on steaming time (p < 0.05). The
R2
coefficient values of bulk density was high (> 0.9), while those of
linear expansion (0.86) and crispiness (0.84) were slightly low, how-
ever fitted quadratic equation. The p values of lack of fit were also large
for all the three cases, which implied that it is not significant relative to
the poor error.
Final equation in terms of coded factors is given as a) Linear
Expansion = 58.40 + 0.18*A – 5.35*B + 2.22*C –
2.77*A*B + 0.29*A*C + 0.21* B*C −1.66*A2
+ 4 B2
+ 3.85*C2
b)
Bulk density = 0.27 + 0.020*A + 0.021*B – 1.875*C
+ 0.036*A*B + 0.024*A*C – 2.750*B*C + 0.049*A2
-
0.016*B2
+ 2.975*C2
c) Crispiness = 7.81–0.74*A +
0.90*B + 0.22*C + 0.81*A*B – 0.27*A*C – 0.69*B*C – 0.14*A2
-
1.27*B2
- 1.40*C2
.
The validity of the models was confirmed by conducting the ex-
periments under the optimum conditions. The predicted values calcu-
lated from these models are presented with the experimental values in
Table 3. The contour plots of linear expansion (Y1), bulk density (Y2),
crispiness (Y3) of fried fish crackers as affected by steaming time (A),
drying temperature (B), and gel setting time (C) are shown in Fig. 4a–c.
The linear expansion of fish crackers increased with the increase in
the steaming time and the decrease in drying temperature as shown in
Fig. 4a1. The expansion increased with the increase in gel setting time
with a maximum at a steaming time of 40 min (Fig. 4a2) and a drying
temperature of 40 °C (Fig. 4a3). The contour plots of linear expansion
clearly indicated the optimum area providing desirable quality attri-
butes of fish crackers.
Fig. 4. a-c. The contour plots of linear expansion, Bulk density and crispiness of fried fish crackers as affected by steaming time (A), drying temperature (B) and gel setting time (C).
Table 3
Box-Behkehn design for optimizing gelatinization conditions of fried crackers in coded
units together with experimental data (Exp) and predicted values (Pred).
Std order A B C Linear Expansion Bulk density Crispiness
Exp Pred Exp Pred Exp Pred
1 1 0 1 66.32 64.14 0.351 0.366 5.211 6.189
2 0 0 0 56.54 58.40 0.286 0.271 7.615 7.808
3 0 0 0 58.74 58.40 0.265 0.271 6.969 7.808
4 −1 1 0 57.71 58.75 0.275 0.289 6.463 7.385
5 0 0 0 61.73 58.40 0.26 0.272 8.527 7.808
6 1 1 0 51.30 57.27 0.4 0.379 7.016 7.372
7 −1 −1 0 64.64 63.94 0.284 0.303 7.384 7.314
8 0 0 0 57.77 58.40 0.272 0.272 6.912 7.808
9 0 −1 1 70.30 73.23 0.259 0.285 4.654 6.101
10 −1 0 −1 55.42 58.53 0.345 0.328 6.779 7.113
11 1 0 −1 56.45 59.83 0.323 0.325 5.429 6.166
12 −1 0 1 64.14 63.24 0.277 0.283 7.623 7.555
13 0 −1 −1 71.14 70.62 0.241 0.273 2.710 6.301
14 0 1 1 67.27 67.08 0.272 0.312 6.179 6.625
15 1 −1 0 69.30 68.30 0.263 0.325 4.694 6.164
16 0 1 −1 61.78 58.36 0.265 0.287 6.982 6.661
17 0 0 0 57.22 58.40 0.276 0.271 8.277 7.808
*A – Steaming time, B –Gel setting time, C –Drying temperature.
R. Ramesh et al. LWT - Food Science and Technology 89 (2018) 248–254
253

7. The bulk density of fish crackers decreased with an increase in
steaming time but not with the drying temperature (Fig. 4b1). The bulk
density has not much relationship with the gel setting time (Fig. 4b2). A
slight increase in the bulk density was noticed as the drying tempera-
ture increased from 40 to 50 °C (Fig. 4b3). The contour plot of bulk
density indicated the optimised parameters for obtaining the desirable
bulkiness of the product, which mainly included the steaming time.
The crispiness of fish crackers increased with the increase in
steaming time but not influenced significantly by the drying tempera-
ture (Fig. 4c1). The crispiness was however not influenced by the gel
setting time (Fig. 4c2) and drying temperature (Fig. 4c3). So, to have an
expanded crispy fish cracker, the steaming time should be between 40
and 60 min.
The optimum processing conditions of deep fried fish crackers were
obtained using optimization tool in Design Expert 7.0 software by using
experimental data and coded values as shown in Table 3. The target
values of steaming time, gel setting time and drying temperature were
set in the program. The results showed that the optimum conditions in
both coded data and experimental data, leading to better linear ex-
pansion, bulk density and crispiness were at a steaming time of 40 min,
a gel setting time of 24 h and a drying temperature of 40 °C.
4. Conclusion
Fish crackers with better linear expansion can be successfully pro-
duced by optimizing the gelatinization conditions. The steaming time,
gel setting time and drying temperature were taken as important pro-
cess parameters responsible for the quality of the fish crackers, i.e.
linear expansion, bulk density and crispiness. High degree of expansion,
low bulk density and high crispiness of 73.23%, 0.271 g/m3
; and
6.101N, respectively were obtained from the crackers prepared out by
optimizing the gelatinization conditions. According to the choice of
consumers, fish crackers with good linear expansion, bulk density and
crispiness shall be processed by taking into consideration the small
variation in the respective process conditions.
Acknowledgements
Authors thank the Department of Fish Processing Technology for
providing the processing facilities and ICAR Niche Area of Excellence of
Fish Safety and Quality Assurance attached with DFQAM for providing
the necessary analytical facilities to carry out this research work suc-
cessfully. The first author acknowledges the Tamil Nadu Fisheries
University for providing merit fellowship to undertake this part of re-
search work.
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