STUDIES ON FOAM-MAT DRYING OF TAMARIND PULP
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Date
2019
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Orissa University of Agriculture and Technology, Bhubaneswar
Abstract
amarind (Tamarindusindica L) fruit is nutritionally and medicinally rich. Fruit production is seasonal and a huge quantity gets wasted every year due to lack of processing technology. The production of powder from the tamarind pulp is not possible due to its high sugar content. So the foam-mat drying of tamarind pulp was carried out to convert pulp into powder using different foaming agents and stabilizers. The effect of adding different proportions of maltodextrin (1 to 3%), methyl cellulose (0.5 to 1.5%) and change in whipping time (5 to 15minutes) on properties of foam were investigated using Box-Behnken design of response surface methodology. The foam-mat was dried under different drying air temperatures (60 to 800C) and foam thickness of 3 and 5mm. The drying conditions were standardized based on drying time, tartaric acid, sensory and functional qualities. The drying kinetics was studied using different empirical models. The efficacy of artificial neural network modeling on foam-mat drying kinetics was tested and was compared to that of best empirical model. The influence of
different packaging materials (MPP, PET and LDPE) and storage conditions (ambient and refrigerated) on storability of foam-mat dried powder was also evaluated.
The process variables of foam-mat drying of tamarind pulp (maltodextrin, methyl cellulose and whipping time) influenced all the responses (foam expansion, foam retention, overall acceptability and tartaric acid). However, methyl cellulose was found to be the most influencing input variable. Among the responses, foam expansion and overall acceptability were observed to be affected more significantly with the variation in input variables. The values of optimum process variables (maltodextrin, methyl cellulose and whipping time) to obtain the multiple responses of the foam-mat dried tamarind powder within the desirable range were 2%, 1.1% and 10 min respectively. At these optimum conditions, the predicted foam expansion, foam retention, overall acceptability and tartaric acid were 75.16%, 95.01%, 7.49 and 12.34%,
respectively. The recommended drying air temperature and the foam thickness are 70 to 800C and 3mm, respectively with respect to drying time, sensory and functional quality parameters based on analysis of variance (p<0.01). The Page model could predict (R2> 0.98) the foam-mat drying kinetics best among all the empirical models tested for all the drying air temperature and foam thickness combinations. The developed ANN model using logsig transfer function could predict the drying kinetics even better (R2> 0.99) than Page model. Modeling of drying kinetics through
ANN was observed to be a better option with drying temperature, foam thickness and drying time
as independent variables as compared to conventional empirical modeling with only drying time
as independent parameter, there by requiring six sets of equations. Storage study indicated that among three packaging materials, only MPP packs could retain the quality parameters of the foam-mat dried tamarind powder up to 2months under ambient condition. No significant change was observed in the samples stored in all three packaging materials under the refrigerated condition till the end of 2months.
Description
Th-5664
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