Process optimization for chalta (Dillenia indica L.) juice extraction
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Date
2015-07
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Fruit of chalta (Dillenia indica L.) having wide range of functional and neutraceuticals is distributed in Sub Himalayan tract and other parts of country but due to lack of awareness and technological advances gets wasted. Therefore, an attempt was made to derive a convenient and easy method for juice extraction from this fruit without compromising with its beneficial counterparts. The present investigation was undertaken to optimize process variables for four different kinds of pre-treatments (hot water, steaming, microwave and enzyme treatment) given to chalta fruit pieces in order to prepare juice/extract from the same. The levels of process variables were optimized by Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM) and prepared extract was subjected to physico-chemical and sensory analysis. Results revealed that in case of microwave treatment, effect of heat treatment time was found highly significant (p<0.01) on acidity, Vitamin C, TSS, colour and aroma of the juice/extract at linear level and for TPC and IC50 at quadratic level and also found significant (p<0.05) for yield and consistency. Extraction time was found to influence acidity, reducing sugar, TPC and TSS of the extract significantly (p<0.05) at linear level and vitamin C and consistency at quadratic level. In steaming treatment, effect of heat treatment time was found highly significant (p<0.01) on acidity, reducing sugar, Vitamin C, TSS, colour, aroma and consistency at linear level and for TPC at quadratic level and it was also significant (p<0.05) for yield at linear level. Similarly, effect of extraction time was found significant (p<0.05) on acidity, reducing sugar and IC50 at linear and for TPC at quadratic level, respectively. It was also observed that in hot water treatment, soaking time affected colour and consistency significantly (p<0.01) at linear level and for vitamin C at quadratic level, whereas, TPC and IC50 were found significant (p<0.05) at both the levels. Extraction time was found to have significant (p<0.05) effect on IC50 and aroma at linear level and for acidity, vitamin C and TSS at quadratic level. Similarly, effect of temperature was found highly significant (p<0.01) on IC50, yield, TSS and consistency at linear level. Interactive effect of soaking time and extraction time on IC50 and heating time and temperature on Vitamin C were found highly significant (p<0.01) for extract from hot water treatment. In enzymatic treatment, results have shown that at linear level, effect of pectinase was found highly significant (p<0.01) on reducing sugar and TSS and significant (p<0.05) for aroma and IC50. Cellulase has also found to affect reducing sugar at linear level and acidity and yield at quadratic level significantly (p<0.01) whereas, incubation time showed highly significant (p<0.01) effect on acidity, vitamin C and consistency at linear level and TPC at quadratic level. TPC was also found to get affected significantly (p<0.01) at interactive level of cellulase and incubation time. Optimum levels obtained for microwave treatment were 4.72 minutes heat treatment and 15 minutes extraction time, while in steam treatment 5 minutes heat treatment time and 44.99 minutes extraction time. In case of dipping optimum levels were 2 hours heat treatment, 45 minutes of extraction and 90°C temperature whereas for enzymatic treatment 1% pectinase concentration , 0.98% cellulose concentration and 2 hour incubation time were obtained. Amongst the four pretreatments viz., hot water treatment, steaming, microwave and enzymatic treatment it was found that physico-chemical attributes including yield, TSS, Vitamin C, reducing sugar and acidity of chalta extract by using enzymatic extraction method while minimum for antioxidant activity (IC50 values) was minimum. Maximum sensory score of color and aroma was also obtained for enzymatic method as compared to other methods of extraction. Hence, enzymatic extraction method is considered best for preparing juice/extract from chalta fruit without adversely affecting the physico- chemical characteristics.
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