Studies on extraction and purification of rebaudioside-A and dehydration of aloe vera gel
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The present work comprises into two parts. In the first part, extraction and purification of rebaudioside A from ‘Stevia’ leaves using water, as a green solvent, were performed followed by process modeling and optimization. The second part covered the dehydration of aloe vera gel using hot air, microwave, and hybrid drying techniques. Stevia rebaudiana (Bertoni) is a medicinal herb which contents eight sweet-tasting glycosides. Among which rebaudioside-A (Reb-A) is the most predominant, having the sweetening potential of about 450 times as compared to the sucrose solution (0.4 % w/v). Reb-A is proposed as a future alternative to sugar. But the challenges lie in its extraction and purification processes due to its lesser quantity in the leaves.The present work studied the extraction of Reb-A using water as a green solvent. The effect of extraction parameters, namely, extraction time, leaves to water ratio, and temperature on Reb-A recovery was investigated. Response surface methodology (RSM) was applied to optimize the extraction process along with the Artificial Neural Network (ANN) modeling. The optimum extraction time was found as 51 min for a leaves to water ratio of 2.36 % at 71°C by which 73 % Reb-A recovery was achieved.
Supervisors: Chandan Das & Animes Kumar Golder