Sugarcane juice properties as control parameters during the
procurement process of granulated panela, process in open system
Las propiedades del jugo de caña como parámetros de control durante el
proceso de obtención de panela granulada proceso en sistema abierto
Nelly Lara1, 3 and Alejandra Clavijo1, 2
ABSTRACT
RESUMEN
Two genotypes of sugarcane were used to study the concentration process of sugarcane juice in open pan by heating at
149 and 177°C. The contents of soluble solids (°Brix), water
activity (aw), titratable acidity (trans aconitic acid, TAA), color
(absorbance), temperature and time were monitored during this
process. Considering time as an independent variable, the rest
of control parameters were predicted by modelling using simple
regression. Specific mathematical models were found to explain
Time-Temperature boiling curve and the trends in °Brix, aw,
TAA and color, having boiling time and temperature as independent variables. While aw decreased, °Brix, TAA and color
increased with both time and boiling temperature. The critical
range of boiling temperature with high influence on °Brix,
aw, TAA and color could be estimated between 95 and 120°C.
Se utilizaron dos genotipos de caña de azúcar para estudiar el
proceso de concentración del jugo en un sistema abierto calentado a 149 y 177°C. El contenido de sólidos solubles (°Brix),
actividad de agua (aw), acidez titulable (trans aconitic acid, TAA),
color (absorbancia), temperatura y tiempo fueron monitoreados
durante este proceso. Con el tiempo como una variable independiente, el resto de parámetros de control fueron predichos por
regresión simple. Se encontraron modelos matemáticos específicos para explicar las curvas de temperatura de ebullición, °Brix,
aw, TAA y color versus tiempo, y también de la temperatura como
variable independiente. Mientras aw disminuyó, °Brix, TAA y
color aumentaron con el tiempo y la temperatura de ebullición. El
intervalo crítico de temperatura con alta influencia sobre °Brix,
aw, TAA y el color fue determinado entre 95 y 120°C.
Key words: juice concentration, boiling, quality parameters,
granulated panela.
Palabras clave: concentración del jugo, ebullición, parámetros
de calidad, panela granulada.
Introduction
Sugar cane is one of the important commercial crops used
to manufacture several types of sweetener such as white,
refined, brown and raw sugar (Harish et al., 2009). Raw
sugar typically takes place in or near sugar cane fields
in rural areas with technological limitations, using open
pans at environment conditions to concentrate sugar cane
juice (Donovan and Williams, 2001). Closely-related to
raw sugar, granulated panela is another presentation of a
traditionally sweetener produced all over the word under
different names, such as gur, desi, jaggery, hakuru, htayet,
panocha, or naam taan oi in Asian and African countries
(Rao et al., 2009; Kumar and Tiwari, 2006), and piloncillo,
papelón, panela, chancaca or raspadura in Latin American
countries (Mujica et al., 2008). Granulated panela has a
long cultural heritage in Central and South America. Most
artisan farmers in these countries use a simple crusher
consisting of two or three metal roller to compress the
sugar cane and extract the juice. The extracted juice is
then filtered and removed from it, macro solid particles by
sedimentation in a pre-cleaner tank. After, in a first open
pan at 60 and 70°C, the clarification of juice is carried out
using natural mucilage (Gonzales, 2001). In a following
step, the clarified juice is concentrated. Boiling temperature is between 89 to 92°C, and the juice is boiled until
soluble solid contents near to 70°Brix. The concentration
of soluble solids in the juice increases the temperature,
exceeding 100°C. Just before of the syrup solidification,
the temperature is ranging between 118 to 125°C, and the
soluble solid content of syrup is higher than 88°Brix. In
this point, the resulting syrup is poured into other pan
and strongly mixed to obtain the granulated panela. This
study shows the increasing of temperature during the
boiling-concentration time of juice batches and its effect
on the soluble solids (°Brix), aw, titratable acidity and color.
ISSN: 0120-9965 Fecha de recepción: 14-06-2016 Aceptado para publicación: 21-09-2016
Doi: 10.15446/agron.colomb.v34n1supl.58455
1
Santa Catalina Experimental Station, Instituto Nacional Autónomo de Investigaciones Agropecuarias (INIAP). Mejía (Ecuador).
Faculty of Chemical Engineering and Agrobusiness, National Polytechnic University. Quito (Ecuador).
3
Faculty of Agricultural Science, Ecuadorian Central University. Quito (Ecuador). [email protected]
2
Agronomía Colombiana 34(1Supl.), S1363-S1366, 2016
Materials and methods
Juice extraction
Two genotypes of sugarcane (POJ 28-78 and POJ 27-14)
were used in this study to characterize the concentration
process of sugarcane juice in open pans. The sugarcane
stems were washed and peeled in an electrical metal brusher
with circular movement (Magtron), and then crushed in
a sugar cane extractor (Magtron, serial B-720) to obtain
the juice. The juice was filtrated through a laboratory test
sieve of 100 microns. A hold house open pan (Cuisinart)
with temperature control was used at 149 and 177°C to
concentrate the sugarcane juice by boiling at environment
condition. Three liters of juice was used each time. The
temperature and time were monitored during the boilingconcentration process while small samples by duplicate,
were taken out to determine the behavior of soluble solids
(°Brix), water activity, titratable acidity and absorbane. The
experiment was carried out by triplicate.
Analysis of samples
Digital and hand refractometer (Atago) of 0-53, 28-62
and 58-90 °Brix were used to measure soluble solids in
juice and syrup. Values of water activity were measured
with a digital water activity meter (AQUALAB) calibrated
with standard solution from 0.2 to 0.9. Titratable acidity
was determined by titration with standardized solution of
NaOH 0.01 N, and expressed as ml of NaOH 0.01 N used
to rise the pH value to 8.3 in 10 ml of sample (Mao et al.,
2007). Color (brown pigment formation) was determined
measuring the absorbance of diluted samples at 420 nm
(Turkment et al., 2006).
Statistical analysis
Plotting temperature, °Brix, aw, titratable and color versus
time; and °Brix, aw, titratable acidity and color versus temperature, the experimental data were analyzed by simple
and polynomial regression using the software Statgraphics
plus version 5.1. Statgraphics centurion, version 16.1.03,
was used to fit temperature and color versus time by more
sophisticated models.
Result and discussion
Models and their parameters were computed for the
treatments resulting from the experimental combination
between two genotypes (POJ 28-78 and POJ 27-14) and two
temperatures, used to heat the open pan at 149 and 177°C.
All relationships were predicted by simple regression (Tab.
1 and 2), excepting water activity versus temperature which
was fitted by polynomial regression with values of 5.36944,
-0.0754317, 0.000297624 for a, b and b2, respectively. Plotting boiling temperature, Brix, water activity, acidity and
color again time, the models selected for the most relevant
treatments were: inverse-Y square-X, exponential, logistic,
exponential and square root-Y square-X, respectively (Tab.
1). In the same way, plotting Brix, acidity and color again
temperature, the models with mayor resolution were:
inverse-X, lineal and lineal, respectively (Tab. 2). The goodness of the models was checked according to the values
of correlation coefficient (r), determination of coefficient
(R 2), standard error (% SE) and provability value (P-value).
Graphically, the influence of time and temperature on
soluble solids, water activity, acidity and color during
sugar cane juice concentration may be used to control the
process. Figure 1 exhibits the increasing change of color
from juice to syrup which was quantified by measuring
the absorbance at 420 nm. Boiling temperature, °Brix,
aw, TAA and color may be useful as control parameters
in order to standard granulated panela making process in
open pans at environmental conditions. The juice of two
genotypes used in granulated panela making process show
similar behavior during sugarcane juice concentration. The
Temperature-Time boiling curve and its trend are highly
influenced by the temperature set to heat sugarcane juice
TABLE 1. Models, constants and statistic values for temperature, °Brix, water activity (aw), titratable acidity and color versus time of sugarcane juice
concentration until solidification.
Simple regression
S1364
Control parameters again time (min) as independent variable
Temperature
°Brix
aw
Acidity
Color
Model
Inverse-Y square-X
Exponential
Logistic
Exponential
Square root-Y square-X
a
0.0111775
2.87644
3.92814
1.89937
-0.32097
b
-5.60E-07
0.0257347
-0.0456760
0.0094768
0.0293154
r
-0.95161
0.98562
-0.91534
0.89713
0.90301
R2
90.5561
97.14
83.7853
80.48
81.54
% SE
0.00033114
0.106
0.494
0.115
0.335
P-value
0.000
0.000
0.000
0.000
0.000
Agron. Colomb. 34(1Supl.), 2016
TABLE 2. Models, constants and statistic values for °Brix, titratable acidity and color versus temperature of sugarcane juice concentration until
solidification.
Control parameters again temperature as independent variable
Simple regression
Model
°Brix
Acidity
Color
Inverse-X
Lineal
Lineal
A
353.95
-5.43072
-6.14444
B
-29491.8
0.154362
0.0693571
R
-0.942982
0.88677
0.967943
R2
88.9216
78.636
93.6913
% SE
10.3921
1.15239
0.190141
P-value
0.000
0.000
0.000
of granulated panela traditionally produced in open pans
at environmental conditions. Consequently, the knowledge
generated about the behavior of these processing factors is
an important base to attempt the quality standardization
of granulated panela at the artisanal scale.
in opens pans. With higher heating temperature higher
°Brix is reached in lower boiling time which also increases
the boiling temperature. Mainly, after 95°C ahead a rapid
increase in boiling temperature was noted which is strong
related to variations exhibited in °Brix, aw, TAA and color
from 95°C. The critical range in boiling temperature could
be between 95 to 120°C and within this range, Brix, aw or
color can be controlled to improve the quality granulated
panela produced in open pans at environmental conditions.
The main correlations evaluated in this study showed that
both time and temperature may be monitored to control
°Brix, water activity, acidity and color during the sugar cane
juice concentration, and thus improve the standard quality
a)
Boiling temperature, °Brix, aw, TAA and color may be
useful as control parameters in order to model granulated
panela making process in open pans at environmental
conditions. The juice of two genotypes used in granulated panela making process show similar behavior during
sugarcane juice concentration. The Time-Temperature
boiling curve and its trend are highly influenced by the
Absorbance (420 nm)
2,5
2,0
Experimental data
Predicted data
1,5
1,0
0,5
0
0
10
20
30
40
50
60
114
119
Time (min)
b)
Absorbance (420 nm)
2,5
2,0
Experimental data
Predicted data
1,5
1,0
0,5
0
89
94
99
104
109
Temperature (ºC)
FIGURE 1. Experimental and predicted values of absorbance (color) during sugar cane juice concentration: a) versus time and b) versus temperature.
Lara and Clavijo: Sugarcane juice properties as control parameters during granulated panela making process in open pan
S1365
temperature (thermal energy) set to heat sugarcane juice
in opens pans. With higher heating temperature higher
°Brix is reached in lower boiling time which also increases
the boiling temperature due to evaporated water. However,
the boiling temperature must be monitored and registered
automatically during the process of sugarcane juice concentration. Mainly, after 95°C ahead a rapid increase in
boiling temperature was noted which is strong related to
variations in Brix, aw, TAA and color also exhibited from
95°C. The critical range in boiling temperature could be
between 95 to 120°C and within this range, °Brix, aw or
color can be controlled to improve the quality granulated
panela produced in open pans at environmental conditions.
The main correlations evaluated in this study showed that
both time and temperature may be monitored to control
Brix, water activity, acidity and color during the sugar cane
juice concentration, and thus improve the standard quality
of granulated panela traditionally produced in open pans
at environmental conditions. Consequently, the knowledge
generated about the behavior of these processing factors is
an important base to attempt the quality standardization
of granulated panela at the artisanal scale.
Acknowledgments
The work was carried out in the Quality and Nutrition
Department, Santa Catalina Experimental Station, INIAP
with the financial support of SENESCYT, Ecuador. The
authors wish to thank the INIAP by institutional facilities.
S1366
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Gonzales, J.E. 2001. Method for producing sugar cane juice. United
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Agron. Colomb. 34(1Supl.), 2016