RESEARCH ARTICLE
Asian Journal of Dairy and Food Research, Volume 41 Issue 2: 196-204 (June 2022)
Optimization of Prickly Pear Juice Clarification for Better
Retention of Betalain and Color Properties
P.R. Davara, A.K. Varshney, V.P. Sangani, P.P. Vora
10.18805/ajdfr.DR-1693
ABSTRACT
Background: Prickly pear juices are considered as valuable ingredient for sports and energy drinks due to its higher amino acids
contents, minerals and attractive red color. Hence, prickly pear fruit has received renewed interest for the production of juice. Up to
date, relatively little work has been reported regarding the manufacturing of prickly pear products. Enzyme has proved to be the key
element for producing clear and stable fruit juice. The present study aimed to optimize the processing parameters for enzymatic
clarification of prickly pear juice. The results of this investigation are expected to provide the suitable process technology for the
production of prickly pear juice with better retention of betalain content and color value.
Methods: Prickly pear pulp was treated with pectinase enzyme at different concentrations (0.01-0.09%), incubation temperatures
(40-60C) and incubation time (60-180 min). The effect of enzymatic treatments on clarity, color index, betalain content and ascorbic
acid content of juice were studied through response s urface methodology by employing second order central composite
rotatable design.
Result: Response surface analysis determined the optimum condition for clarifying prickly pear juice as 0.036% enzyme concentration,
46C incubation temperature and 112 min incubation time. At this condition, it was predicted to produce the prickly pear juice with
clarity of 48.59% T, color index of 0.603 abs, betalain content of 542.93 mg/L of juice and ascorbic acid content of 9.35 mg/100 g with
the desirability of 0.780.
Key words: Betalain content, Color, Enzymatic treatment, Juice clarification, Pectinase, Prickly pear.
INTRODUCTION
Juice production is one of the most frequently utilized
process technologies in the fruit processing industry. Juices
are much appreciated for their nutritive value and sensory
properties (Kgatla et al., 2011). Prickly pear juices are
considered as a valuable ingredient for sports and energy
drinks due to its higher amino acids contents (Seidl et al.,
2000). The pulp has an attractive color that varies from soft
green, greenish-white, canary-yellow, orange-yellow, lemonyellow, red and cherry-red to purple hues (Sáenz and
Sepúlveda 2001). These attractive colors are due to the
betalains comprising the red-violet betacyanins and the
yellow-orange betaxanthins (Fernandez- López and LuisAlmela 2001). The other functional benefits such as immunity
boost up, bones and teeth building, digestive health
maintenance, heart health enhancement, anti-carcinogenic
effects, antioxidant potential, weight loss effects and
inflammation suppression are also associated with this fruit
(Joshi et al., 2020). Due to this color property, prickly pear
juice has been considered as valuable source for enhancing
the nutritional content and color in fruit juice blends viz.,
orange-apple juice blends (Moreno-Álvarez et al., 2003).
The key of producing clear and stable fruit juice is a
complete enzymatic breakdown of pectin (Lee et al., 2006).
The treatment of mash with pectinases causes the degradation
of cell wall and middle lamella of plant cells. This releases
the fruit juice and increases yield (Demir et al., 2001; Saxena
et al., 2014). (Enzymatic treatments using pectinase have
also assisted in the improvement of yield and reduction of
196
Department of Processing and Food Engineering, College of
Agricultural Engineering and Technology, Junagadh Agricultural
University, Junagadh-362 001, Gujarat, India.
Corresponding Author: P.R. Davara, Department of Processing
and Food Engineering, College of Agricultural Engineering and
Technology, Junagadh Agricultural University, Junagadh-362 001,
Gujarat, India. Email: pareshdavara@yahoo.com
How to cite this article: Davara, P.R., Varshney, A.K., Sangani,
V.P. and Vora, P.P. (2022). Optimization of Prickly Pear Juice
Clarification for Better Retention of Betalain and Color Properties
41(2): 196-204. DOI: 10.18805/ajdfr.DR-1693.
Submitted: 19-04-2021
Accepted: 16-10-2021
Online: 07-01-2022
turbidity of prickly pear juice (Davara et al., 2017). The
fundamental physical property of food products is color. Color
of juice is affected by natural enzymes, oxidation of ascorbic
acid and the Maillard reaction, which depends on the content
of reducing sugars, proteins and temperature (Mackay et al.,
1990). The enzymatic hydrolysis of pectic substances
depends on several processing variables such as type of
enzyme, hydrolysis time, enzyme concentration, incubation
temperature and pH (Lee et al., 2006; Sin et al., 2006). These
parameters need to be optimized for maximum clarity and
color retention of juice. In order to this, optimization studies
for prickly pear juice clarification were conducted using
response surface methodology (RSM). The aim of the study
was to assess the effect of enzymatic process parameters
on different quality and color characteristics of clarified
Asian Journal of Dairy and Food Research
Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties
prickly pear juice and to optimize the process condition
through response surface methodology.
MATERIALS AND METHODS
The experiment was carried out at Department of Processing
and Food Engineering, College of Agricultural Engineering
and Technology, Junagadh Agricultural University, Junagadh.
Raw materials
The prickly pear fruits were collected from the plants grown
at nearby areas of Junagadh (Gujarat, India). Fully ripe fresh,
bright red and purple color fruits, without any visual defects,
were selected for the experimental work. Commercial food
grade pectinase enzyme was purchased from HiMedia
Laboratories Pvt. Ltd., Mumbai (Maharashtra, India) and
stored at 4C. The activity of pectinase enzyme as reported
by the supplier was 8000-12000 U/g.
Enzymatic clarification
For each experiment, 100 g pulp was subjected to different
enzymatic treatments under different conditions as shown
in Table 1. The pectinase enzyme was added to each pulp
sample and placed in an incubator for incubation at desired
levels of temperature and time. At the end, suspension was
heated in a water-bath at 90C for 5 min to inactivate the
enzyme present in the sample (Lee et al., 2006). The enzyme
treated prickly pear pulp samples were then centrifuged at
3600 rpm for 10 minutes. The supernatant was collected
and then filtered using 2 folds muslin cloth to get the clear
prickly pear juice. It was then filled in glass bottles and stored
at 7C in refrigerator for further analysis.
Physicochemical analysis
Clarity was determined by measuring the percent
transmittance (%T) at wavelength of 660 nm using UV-VIS
spectrophotometer (UV 5704SS, Electronics Corporation of
India Pvt. Ltd., Hyderabad, India) (Lee et al., 2006). Distilled
water was used as reference. The color index was
determined as per the method proposed by Meydov et al.
(1977). The betalain content of prickly pear juice was
quantified as per the method proposed by Nilsson (1970).
The betalain content was calculated using an equation
proposed by Cai and Corke (1999). Ascorbic acid was
determined by the method described by Hans (1992). The
ascorbic acid content was calculated as mg/100 g of
edible portion.
Experimental design and statistical analysis
Response surface methodology has found be very useful
and reliable method for optimizing the process parameters
in many of the research experiments (Kaur et al., 2018;
Prema et al., 2018; Balasubramanian et al., 2020). It was
used for designing of the experiment (Khuri and Cornell
1987). The software package Design Expert version 10 was
used to generate the experimental designs, statistical
analysis and regression models. A three-factor five-level
central composite rotatable design (CCRD) with quadratic
Volume 41 Issue 2 (June 2022)
model was employed to study the combined effect of three
independent variables, viz., enzyme concentration,
incubation temperature and incubation time on different
response variables. The response function (Y) was related
to the coded variables by a second order polynomial
equation which can be given as under:
Y = b0 + b1X1 + b2X2 + b3X3 + b11X12 + b22X22 +b33X32 + b12X1X2
+ b12X1X2 + b12X1X3 + b23X2X3
.....(1)
The coefficients of polynomial were represented by b0
(constant term), b1, b2 and b3 (linear effects), b11, b22 and b33
(quadratic effects) and b12, b13 and b23 (interaction effects).
Analysis of variance (ANOVA) tables were generated and
regression coefficients of individual linear, quadratic and
interaction terms were determined (Khuri and Cornell 1987).
Optimization and validation of process variables
The optimization of process variables was carried out using
Design Expert software. Optimum values of the selected
variables were analyzed by the response surface contour
plots and also by solving the regression equation. The
optimum condition as obtained through response surface
analysis was verified by conducting the experiments in
triplicate. The average experimental value of different
response variables was used to check the validity and
adequacy of the predicted models.
RESULTS AND DISCUSSION
Effect of enzymatic treatment on clarity of juice
The effect of enzyme concentration, temperature and time
on clarity of prickly pear juice is presented in the Table 1.
Fig 1a showed that the clarity of juice was increased with
an increase in the enzyme concentration and incubation
temperature up to 0.087% and 43C, respectively. It was
expected to be increased up to 50.94%T at this combination
of enzyme concentration and temperature. The perusal of
contour map (Fig 2a) indicated that the clarity of juice was
increased with an increase in incubation temperature up to
47C and incubation time up to its maximum level of 180
min. This interaction level of temperature and time was
proposed to increase the juice clarity up to 55.04%T. The
interaction of enzyme concentration and incubation time
caused to increase the clarity up to 54.81%T (Fig 3a). The
enzyme concentration and incubation time at this juncture
was determined as 0.062% and 180 min, respectively. The
higher incubation time provided the sufficient time to
pectinase for breakdown of pectin which was the main
phenomenon responsible for increase in juice clarity after
prolonged time (Karangwa et al., 2010). The resultant model,
giving the empirical relation between the clarity of juice and
the test variables in coded units, was obtained as under:
Clarity= 49.51+0.285X1-10968X2+1.983X3-0.787X12-1.975X22
+ 0.641X32 - 1.806X1X2 + 0.271X1X3 + 0.111X2X3
.....(2)
Effect of enzymatic treatment on color index of juice
The data as tabulated in Table 1 as well as the interaction
197
Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties
plots of color index of prickly pear juice (Fig 1b) showed the
positive effect of enzyme concentration and incubation
temperature up to 0.047% and 44C, respectively. This
interaction was expected to increase the color index of juice
up to 0.612 abs. However, with further increase in enzyme
concentration and incubation temperature, the color index
was decreased. Similarly, the positive effect of interaction
of incubation temperature and time on color index of prickly
pear j uice was observed up to 44 C and 126 min,
respectively. It was likely to be increased up to 0.612 abs at
this combination of temperature and time (Fig 2b). Further
increase in incubation temperature and time reduced the
color index of juice. The interaction of enzyme concentration
and incubation time, was effective up to 0.042% and 131
min, respectively. This interaction was expected to improve
the color index of juice up to 0.596 abs (Fig 3b). But, the
color index was decreased with further rise in enzyme
concentration and incubation time. The regression model
as derived for the color index of juice is given as under:
Color index =
0.593-0.009X1- 0.034X2 + 0.008X3 -0.016X12 -0.016X22 +
0.017X32 - 0.005X1X2 + 0.008X1X3 + 0.002X2X3
.....(3)
Effect of enzymatic treatment on betalain content
The data showing the effect of enzyme concentration,
temperature and time on betalain content of clarified prickly
pear juice are tabularized in Table 1. The response surface
and contour plot for the betalain content of juice as a function
of enzyme concentration and incubation temperature (Fig 1c)
revealed that betalain content of juice was increased with
an increase of enzyme concentration up to 0.05% and
incubation temperature up to 47C, respectively. For this
interaction, it was possible to increase the betalain content
of juice up to 544.80 mg/L. The contour map for betalain
content (Fig 2c) indicated that interaction of incubation
temperature and time positively affected the betalain content
till 47C and 128 min, respectively. The betalain content of
the juice was expected to be increased up to 544.90 mg/L
of juice at this combination of temperature and time. The
betalain content was found to be decreased with further
increase in temperature and time. For the third interaction
as shown Fig 3c, the betalain content was found to be
increased up to 0.053% enzyme concentration and 147 min
incubation time. This combination was expected to increase
the betalain content up to 542.64 mg/L of j uice. The
following empirical model in coded form was derived for
the betalain content.
Betalain conttent =
542.635-0.687X1 -8.237X2 +3.532X3 - 5.356X12 - 7.836X22
+ 2.957X32 - 1.498X1X2 + 0.41X1X3 + 5.025X2X3
......(4)
Effect of enzymatic treatment on ascorbic acid
Increase of enzyme concentration and incubation
temperature, could play the beneficial role only up to 0.062%
Table 1: Effect of enzyme concentration, incubation temperature and incubation time on response variables of clarified prickly pear juice
Independent variables
Treatment
no.
Responses
Enzyme conc.
Temp.
Time
Clarity
Color index
Betalain content
Ascorbic acid
(%)
(C)
(min)
(%T)
(abs)
(mg/L of juice)
(mg/100 g)
X1(x1)
X2(x2)
X3(x3)
Y1
Y2
Y3
Y4
0.026(-1)
44(-1)
84(-1)
46.31
0.581
538.51
9.56
2
0.074(1)
44(-1)
84(-1)
50.02
0.580
537.21
9.28
3
0.026(-1)
56(1)
84(-1)
45.75
0.502
508.91
9.23
1
4
0.074(1)
56(1)
84(-1)
42.12
0.497
511.62
8.95
5
0.026(-1)
44(-1)
156(1)
49.14
0.601
536.56
8.99
6
0.074(1)
44(-1)
156(1)
53.82
0.585
534.92
9.32
7
0.026(-1)
56(1)
156(1)
48.91
0.544
525.08
8.66
8
0.074(1)
56(1)
156(1)
46.48
0.494
531.41
8.85
9
0.01(-1.682)
50(0)
120(0)
46.21
0.558
524.33
9.14
10
0.09(1.682)
50(0)
120(0)
47.14
0.531
526.28
9.10
11
0.05(0)
40(-1.682)
120(0)
46.54
0.591
530.87
9.28
12
0.05(0)
60(1.682)
120(0)
40.09
0.498
505.71
8.63
13
0.05(0)
50(0)
60(-1.682)
46.87
0.528
527.18
9.23
14
0.05(0)
50(0)
180(1.682)
54.56
0.555
537.00
8.71
15
0.05(0)
50(0)
120(0)
48.92
0.592
540.95
9.25
16
0.05(0)
50(0)
120(0)
49.27
0.588
544.00
9.27
17
0.05(0)
50(0)
120(0)
48.70
0.600
544.67
9.24
18
0.05(0)
50(0)
120(0)
50.49
0.582
540.06
9.16
19
0.05(0)
50(0)
120(0)
49.22
0.595
543.73
9.23
20
0.05(0)
50(0)
120(0)
50.67
0.603
543.15
9.21
Note: Value s in parenthesis are coded value.
198
Asian Journal of Dairy and Food Research
Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties
Clarity (%T)
60
52
48.2
44.4
40.6
36.8
33
60
0.090
56
0.074
52
56
B : In c u b a tio n te m p e r a tu re
C la rity (% T )
40
45
47.4438
48.0497
48.5593
52
49.0566
48
50
50.5891
44
50.9298
45
0.058
48
40
40
0.042
0.010
B: Incubation temperature
44
0.026
0.026
0.042
0.058
0.074
0.090
A: Enzyme concentration
A: Enzyme concentration
40 0.010
a. Clarity of juice
Colour index (abs)
0.615
0.575
0.535
0.496
0.456
0.416
60
0.090
56
0.074
52
B : In c u b a tio n te m p e r a tu r e
C o lo u r i n d e x (a b s )
60
0.5
0.45
56
0.55
0.576932
52
0.6
48
44
0.611646
0.058
48
B: Incubation temperature
40
0.042
0.010
44
0.026
0.026
0.042
0.058
0.074
0.090
A: Enzyme concentration
40 0.010
A: Enzyme concentration
b. Color index of juice
Betalain content (mg/L of juice)
520
510
530
560.000
546.000
532.000
518.000
504.000
490.000
60
0.090
56
0.074
52
B : In c u b a tio n te m p e r a t u r e
B e ta l a i n c o n te n t ( m g /L o f j u ic e )
60
56
540
52
48
557.165
555.177
44
540
540
0.058
48
0.042
530
0.010
B: Incubation temperature
44
0.026
40
550
40
0.026
0.042
0.058
0.074
0.090
0.074
0.090
A: Enzyme concentration
A: Enzyme concentration
0.010
c. Betalain content of juice
Ascorbic acid (mg/100g)
60
56
9.350
9.198
9.046
8.894
8.742
8.590
60
0.090
56
0.074
52
B : In c u b a t io n te m p e ra tu r e
A s c o rb ic a c id (m g /1 0 0 g )
8.8
9
52
9.2
48
9.30739
44
9.34387
0.058
9.33757
40
48
B: Incubation temperature
0.042
44
0.026
0.010
0.026
0.042
0.058
A: Enzyme concentration
A: Enzyme concentration
40 0.010
d. Ascorbic acid content of juice
Fig 1: Interaction effect of enzyme concentration and incubation temperature on clarity, color index, betalain content and ascorbic
acid (Incubation time was at the centre point, i.e. 120 min).
Volume 41 Issue 2 (June 2022)
199
Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties
and 42C, respectively and expected to increase the
ascorbic acid up to 9.34 mg/100 g (Fig 1d). Increase in
ascorbic acid was observed with the increase of incubation
temperature and time up to 43C and 86 min, respectively
(Fig 2d). This interaction predicted the rise in ascorbic acid
up to 9.40 mg/100 g. The interaction effect as presented
through contour graph (Fig 3d) revealed that there was
decrease in ascorbic acid in the juice with an increase in
both enzyme concentration and incubation time. Incubation
time had shown its significant effect in decreasing ascorbic
acid in comparison to enzyme concentration. Therefore, the
lowest ascorbic acid (8.36 mg/100g) was observed at
combination of 0.01% enzyme concentration and 180 min
incubation time. W hile, the highest (9.63 mg/100 g) was
observed for the interaction of 0.01% enzyme concentration
and 60 min incubation time. The model as derived and giving
the empirical relation between ascorbic acid vale and test
variables in coded units, was obtained as under:
Ascorbic acid =
9.223-0.008X 1 -0.187X 2 + 0.152X 3-0.016X 12-0.074X 22
+0.069X32 -0.018X1X2+0.135X1X3+0.018X2X 3
.....(5)
Fitting the model
The different models for the different dependent variables,
viz. clarity, color index, betalain content and ascorbic acid,
were derived as represented by the Eq. 2, Eq. 3, Eq. 4 and
Eq. 5, respectively. The values of different indicators for the
model fitting were obtained for these selected parameters
as reported in the Table 2. The calculated F-value was
significant at p<0.001 for all the selected responses. At the
same time, all these parameters possessed non-significant
lack of fit (p>0.05). These values indicated that the models
as derived for all the selected parameters were fitted and
reliable. The R2 and Adj-R 2 value for all the responses as
determined through regression analysis were higher than
the 0.8, which demonstrated the adequacy, good fit and high
significance of the model. The Pred-R 2 value for all the
factors was in reasonable agreement with the Adj-R2. The
high Adeq Precision value (>4) again supported the
significance of all the derived models. The small value of
coefficient of variation for all the responses explained that
the experimental results were precise and reliable (Table 2).
Optimization of process variables
Among the different independent variables, enzyme
concentration has the greatest impact on the processing
cost. To economize the process, minimum enzyme
concentrations were used as criteria in numerical
optimization and ideal operational conditions were derived.
Accordingly, the goals that were set for variables and
responses to obtain the optimum processing condition are
illustrated in the Table 3. Under these constraints, the
optimum treatment conditions were found to be, 0.036%
(w/w) enzyme concentration, 46C incubation temperature
and 112 min incubation time. The analysis showed that at
Table 2: ANOVA table for different quality characteristics of clarified prickly pear juice.
Source
Model
Clarity
Color index
Betalain content
Ascorbic acid
(%T)
(abs)
(mg/L of juice)
(mg/100 g)
49.51***
0.593**
542.63***
9.223***
Linear terms
b1 (X1)
0.285
-0.009*
0.69
-0.008
b2 (X2)
-1.968***
-0.034***
-8.24***
-0.187***
b3 (X3)
1.983***
0.008*
3.53***
-0.152***
Interaction terms
b12 (X1X2)
-1.806***
-0.005
1.50
-0.018
b13 (X1X3)
0.271
-0.008
0.41
0.135***
b23 (X2X3)
0.111
0.002
5.03***
-0.018
Quadratic terms
b11 (X12)
-0.787**
-0.016***
-5.36***
-0.016
b22 (X22)
-1.975***
-0.016***
-7.84***
-0.074**
b33 (X32)
0.641*
-0.017***
-2.96**
-0.069**
R2
0.963
0.965
0.971
0.961
Adj-R 2
0.929
0.934
0.945
0.925
Pred-R 2
0.815
0.793
0.821
0.740
Adeq. precision
22.11
16.21
18.51
19.42
F-value
28.56
30.71
37.57
27.15
Indicators for model fitting
Lack of fit
NS
NS
NS
NS
C.V., %
1.87
1.79
0.52
0.73
X1 = Enzyme concentration, X2 = Incubation temperature, X3 = Incubation time.
***Significant at p<0.001, **Significant at p<0.01, *Significant at p<0.05.
200
Asian Journal of Dairy and Food Research
Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties
Clarity (%T)
180
54.2237
52.593
C la rity (% T )
53
50.2
47.4
44.6
41.8
39
180
60
C : In c u b a tio n tim e
156
0.050
51.2147
50.5891
132
48.0497
47.4438
50
45
49.0566
108
48.0497
47.4438
48.5593
40
84
156
56
132
52
108
48.5593
60
48
40
C: Incubation time
84
44
44
48
52
56
60
B: Incubation temperature
B: Incubation temperature
60 40
a. Clarity of juice
Colour index (abs)
180
0.575
0.538
0.500
0.463
0.425
180
C : I n c u b a t i o n t im e
C o lo u r in d e x (a b s )
156
0.050
0.613
60
156
132
0.6
0.576932
0.611646
0.5
0.55
108
84
56
132
0.45
52
108
60
48
40
C: Incubation time
84
44
44
48
52
56
60
B: Incubation temperature
B: Incubation temperature
60 40
b. Color index of juice
Betalain content (mg/L of juice)
540
156
0.050
560.000
546.000
532.000
518.000
504.000
490.000
180
C : I n c u b a ti o n t im e
B e ta la in c o n te n t (m g /L o f ju ic e )
180
60
156
132
557.165
540
530
108
555.177
520
84
510
56
500
132
52
C: Incubation time
550
60
108
48
84
44
40
44
48
52
56
60
B: Incubation temperature
B: Incubation temperature
60 40
c. Betalain content of juice
Ascorbic acid (mg/100g)
180
0.050
9.200
8.900
8.600
8.300
8.000
180
60
C : In c u b a tio n ti m e
A s co rbic a c id (m g /1 0 0 g )
8.6
156
9.500
9
9.2
9.3268
108
9.40266
84
156
9.39202
56
132
52
108
C: Incubation time
60
48
84
44
8.8
132
40
B: Incubation temperature
60 40
44
48
52
56
60
B: Incubation temperature
d. Ascorbic acid content of juice
Fig 2: Interaction effect of incubation temperature and incubation time on clarity, color index, betalain content and ascorbic acid
(Enzyme concentration was at the centre point, i.e. 0.05%).
Volume 41 Issue 2 (June 2022)
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Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties
Clarity (%T)
180
54.2237
52.593
156
53
51.2147
C : In c u b a ti o n t im e
C la r it y ( % T )
51.4
49.8
48.2
46.6
45
49.0566
108
47.4438
48.5593
47.4438
84
0.090
180
50
132
48.0497
0.074
156
0.058
132
60
0.042
108
0.010
0.026
0.042
0.058
0.074
0.090
A: Enzyme concentration
0.026
84
C: Incubation time
60 0.010
A: Enzyme concentration
a. Clarity of juice
Colour index (abs)
180
0.5
156
0.573
C : I n c u b a ti o n t i m e
C o l o u r in d e x ( a b s )
0.597
0.549
0.526
0.502
0.478
132
0.595764
0.592789
108
0.576932
0.55
84
180
0.090
156
0.074
132
0.5
0.058
108
C: Incubation time
84
0.026
60
0.010
0.5
60
0.010
0.042
0.026
0.042
A: Enzyme concentration
0.058
0.074
0.090
A: Enzyme concentration
b. Color index of juice
Betalain content (mg/L of juice)
156
560.000
C : In c u b a tio n t im e
B e t a la in c o n t e n t ( m g / L o f ju ic e )
180
554.000
548.000
542.000
536.000
530.000
180
555.177
540
108
550
84
0.090
156
556.07
132
540
0.074
132
530
530
0.058
60
108
0.042
C: Incubation time
84
0.026
0.010
0.026
0.042
0.058
0.074
0.090
A: Enzyme concentration
A: Enzyme concentration
60 0.010
c. Betalain content of juice
Ascorbic acid (mg/100g)
180
8.6
9
156
9.420
C : In c u b a tio n tim e
A s c o rb ic a c id (m g /1 0 0 g )
8.8
9.700
9.140
8.860
8.580
8.300
180
9.12056
132
9.2
108
9.3268
9.40266
9.12056
84
0.090
9.5181
156
9
0.074
132
0.058
108
C: Incubation time
0.042
84
0.026
60
0.010
0.026
0.042
0.058
0.074
0.090
A: Enzyme concentration
A: Enzyme concentration
60 0.010
d. Ascorbic acid content of juice
Fig 3: Interaction effect of enzyme concentration and incubation time on clarity, color index, betalain content and ascorbic acid
(Incubation temperature was at the centre point, i.e. 50C).
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Asian Journal of Dairy and Food Research
Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties
Table 3: Numerical optimization of prickly pear juice clarification.
Variables
Constraint
Goal
Enzyme concentration (%)
Optimum value
Minimize
0.036
Incubation temperature (C)
In the range
46.4 (46)
Incubation time (min)
In the range
112.4 (112)
Responses
Constraint
Goal
Predicted value
Experimental value
Clarity (%T)
Maximize
48.59
47.86
1.50
Color index (abs)
Maximize
0.603
0.598
0.83
Betalain content (mg/L of juice)
Maximize
542.93
536.54
1.18
Ascorbic acid (mg/100 g)
Maximize
9.346
9.14
2.20
-
0.780
-
-
Desirability
this combination of enzyme concentration, incubation
temperature and incubation time, it would be possible to
produce the juice with a clarity of 48.59% T, color index of
0.603 abs, betalain content of 542.93 mg/L of juice and
ascorbic acid of 9.35 mg/100 g. Using these optimized
conditions, the experiments were again conducted to find
the variation in the different response variables. The results
revealed that the experimental values of conducted
experiments were very close to the predicted values
(Table 3). This implied that there was a high degree of fit
between the observed and predicted values from the
regression models and each model was quite accurate in
prediction. The closeness of the observed and predicted
responses indicated the validity of developed model.
CONCLUSION
The commercial pectinase enzyme presented an excellent
result for improving the clarity of prickly pear juice with better
retention of other quality parameters. The different process
conditions for enzymatic treatment revealed that all these
selected variables noticeably affected the clarity, color index,
betalain content and ascorbic acid content of the prickly pear
juice. The second order polynomial equations adequately
described the relations between the processing and
response variables. The response surface and contour plots
assisted to study the interaction effect of process variables
on response variables as well as to obtain the optimum levels
for enzymatic pretreatments. The optimum condition for
clarification of prickly pear juice could be recommended as:
enzyme concentration of 0.036%, incubation temperature
of 46C and incubation time of 112 min. The obtained result
would be beneficial for juice industry to improve the clarity
and color index along with preservation of betalain content
and ascorbic acid of the prickly pear fruit juice.
REFERENCES
Balasubramanian, S., Shukla, V. and Singh, R. (2020). Optimization
of process parameters for soaked soybean splits roasting
using response surface methodology. Asian Journal of
Dairy and Food Research. 39(4): 308-316. DOI: 10.18805
/ajdfr.DR-1541.
Volume 41 Issue 2 (June 2022)
Deviation (%)
Cai, Y.Z. and Corke, H. (1999). Amaranthus betacyanin pigments
applied in model food systems. Journal of Food Science. 64:
869-873.https://doi.org/10.1111/j.1365-2621.1999.tb 15930.x.
Davara, P.R., Varshney, A.K., Naliapara, V.A. and Sangani, V.P. (2017).
Response surface modeling of prickly pear juice clarification.
Advances in Food Science and Engineering. 1(2): 80-92.
Demir, N., Acar, J., Sarıoğlu, K. and Mutlu, M. (2001). The use of
commercial pectinase in fruit juice industry. Part 3: Immobilized
pectinase for mash treatment, Journal of Food Engineering.
47: 275-280. https://doi.org/10.1016/S0260-8774 (00)
00127-8.
Fernandez-López, J.A. and Luis-Almela, L. (2001). Application of highperformance liquid chromatography to the characterization
of the betalain pigments in cactus pear fruits. Journal of
Chromatography. 913(1-2): 415-420. https://doi.org/
10.1016/S0021-9673(00)01224-3.
Hans, Y.S.H. (1992). The Guide Book of Food Chemical Experiments,
Pekin Agricultural University Press, Pekin, USA.
Joshi, S., Singh, A., Laobangdisa, S.B. and Kulkarni, S. (2020).
Utilization of prickly pear for preparation of fruit dessert.
Asian Journal of Dairy and Food Research. 39(1): 58-65.
DOI: 10.18805/ajdfr.DR-1476.
Karangwa, E., Khizar, H., Rao, L., Nshimiyimana, D.S., Foh, M.B.K.,
Li, L., Xia, S.Q. and Zhang, X.M. (2010). Optimization of
processing parameters for clarification of blended carrotorange juice and improvement of its carotene content.
Advance Journal of Food Science and Technology. 2(5):
268-278.
Kaur, R., Singh, P.K., Talwar, G. and Anurag (2018). Studies on
sensory and textural properties of milk cake using response
surface methodology. Asian Journal of Dairy and Food
Research. 37(3): 167-174. DOI: 10.18805/ajdfr.DR-1316.
Kgatla, T.E., Howard, S.S. and Hiss, D.C. (2011) Colour stability of
wild cactus pear juice. W orld Academy of Science,
Engineering and Technology. 56: 249-254. https://doi.org/
10.5281/zenodo.1080476.
Khuri, A.I. and Cornell, J.A. (1987). Response Surface Design and
Analysis. Marcel Dekker, Inc., New York.
Lee, W.C., Yusof, S., Hamid, N.S.A. and Baharin, B.S. (2006).
Optimizing conditions for enzymatic clarification of banana
juice using response surface methodology (RSM). Journal
of Food Engineering. 73(1): 55-63. https://doi.org/10.1016
/j.jfoodeng.2005.01.005.
203
Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties
Mackay, G., Brown, J. and Torrence, C. (1990). The processing
potential of tubers of the cultivated potato, Solanum
tuberosum L. after storage at low temperatures. Potato
Research. 33: 211-218. https://doi.org/10.1007/BF02358448.
Meydov, S., Saguy, I. and Kopelman, I. (1977). Browning determination
in citrus products. Journal of Agricultural and Food Chemistry.
25(3): 602-604. https://doi.org/10.1021/jf60211a030.
Moreno-Álvarez, M.J., Medina, C., Antón, L., García, D. and BelénCamacho, D. (2003). Uso de pulpa de tuna (Opuntia boldinghii)
en la elaboración de bebidas cítricas pigmentadas.
Interciencia. 28(9): 539-543.
Nilsson, T. (1970). Studies into the pigments in beetroot (Beta vulgaris
L. ssp. vulgaris var. rubra L.). Lantbrukhogskolans Annaler.
36: 179-219.
Prema, R.S., Abirami, A., Nandhini, R. and Ravi Kumar, G. (2018).
Optimization of ingredients composition of non-wheat
pasta based on cooking quality using response surface
methodology (RSM). Asian Journal of Dairy and Food
Research. 37(3): 227-231. DOI: 10.18805/ajdfr.DR-1331.
204
Sáenz, C. and Sepúlveda, E. (2001). Cactus pear juices. Journal of
the Professional Association for Cactus Development.
4: 3-10.
Saxena, D., Sabikhi, L., Chakraborty, S.K. and Singh, D. (2014).
Process optimization for enzyme aided clarification of
watermelon juice. Journal of Food Science and Technology.
51(10): 2490-2498. https://doi.org/10.1007/s13197-0120720-1.
Seidl, R., Peyrl, A., Nicham, R. and Hauser, E. (2000). A taurine and
caffeine-containing drink stimulates cognitive performance
and well-being. Amino Acids. 19: 635-642. https://doi.org/
10.1007/s007260070013.
Sin, H.N., Yusof, S., Hamid, N.S.A. and Rahman, R.A. (2006).
Optimization of enzymatic clarification of sapodilla juice
using response surface methodology. Journal of Food
Engineering. 73: 313-319. https://doi.org/10.1016/j.jfood
eng.2005.01.031.
Asian Journal of Dairy and Food Research
Optimization of Prickly Pear Juice Clarification for Better Retention of Betalain and Color Properties
Asian Journal of Dairy and Food Research, 2022
Background: Prickly pear juices are considered as valuable ingredient for sports and energy drinks due to its higher amino acids contents, minerals and attractive red color. Hence, prickly pear fruit has received renewed interest for the production of juice. Up to date, relatively little work has been reported regarding the manufacturing of prickly pear products. Enzyme has proved to be the key element for producing clear and stable fruit juice. The present study aimed to optimize the processing parameters for enzymatic clarification of prickly pear juice. The results of this investigation are expected to provide the suitable process technology for the production of prickly pear juice with better retention of betalain content and color value. Methods: Prickly pear pulp was treated with pectinase enzyme at different concentrations (0.01-0.09%), incubation temperatures (40-60°C) and incubation time (60-180 min). The effect of enzymatic treatments on clarity, color index, betalain cont......Read more
