Pectinase extraction from orange peelings and its application in tamarind juice extract
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In this study, pectinase enzyme was prepared from orange peelings (as a source of pectin) and Aspergillus niger. Aspergillus niger suspension was obtained from washing black grape berries with distilled water. This was then inoculated on 8 plates containing Potato Dextrose Agar medium (PDA) and incubated at 30°C for 5 days. After incubation all the 8 plates had black colonies of Aspergillus niger. The pectin was obtained from orange peelings (which were first oven dried at 55°C) through citrus acid extraction method. The spores and the orange peelings were mixed together with peptone as a nitrogen source and incubated at room temperature on an orbital shaker for 24 hrs yielding pectinase enzyme solution. The filtered pectinase was applied to separate juice samples (each containing 100 ml of hot water extracted tamarind juice). The first tamarind juice sample (TJ15) had 15 ml of pectinase, followed by TJ10 with 10 ml, then TJ5 with 5 ml and lastly TJ0 without pectinase treatment. The mixtures were then incubated at 45°C for 6hrs. The resultant juice was sensory evaluated by a panel of 12 members. This was done using the 9-point hedonic scale. The sensory attributes evaluated included: appearance, texture and overall acceptability. Tamarind juice sample15 (TJ15) had the highest scores in all sensory attributes evaluated, followed by TJ10, then TJ5 and finally TJ0. The mean and the standard deviations of the scores from the panelists were calculated with; TJ15 having: 6.92±1.12 (appearance), 6.50±1.25 (texture) and 7.42±2.42 (overall acceptance), TJ10 had 6.83±1.25 (appearance), 5.83±1.12 (texture) and 6.25±2.06 (overall acceptance), TJ5 had 6.73±1.41 (appearance), 4.50±2.00 (texture) and 5.58±2.12 (overall acceptance), and finally TJ0 had 4.42±2.00 (appearance), 4.42±2.14 (texture) and 4.00±2.00(overall acceptance). These results showed that the Pectinase enzyme produced had a great impact on the breakdown of tamarind pulp to release the juice which was clear with less turbidity and fine texture. They also demonstrate successful extraction of pectin, pectinase and its application in tamarind juice extraction.