Process intensification for enzyme assisted turmeric starch hydrolysis in hydrotropic and supercritical conditions

Abstract

Abstract The turmeric rhizome (Curcuma longa) contains curcuminoids embedded in the starch matrix. It is thus important to target starch hydrolysis to enhance extraction of curcuminoids. In the case of starch hydrolysis, α-amylase is more efficient when the starch is in a gelatinised form than when it is in its natural form. The present work includes hydrolysis of turmeric starch in its natural and gelatinised forms using α-amylase in hydrotrope solution (HS) and scCO2. The optimum rate of starch hydrolysis was obtained using 200 IU cm−3 of α-amylase, at reaction conditions of 6.5 pH at 328 K when 10% w/w of turmeric powder was stirred at 900 rpm in HSs. The hydrolysis in 15 MPa scCO2 at room temperature required a phase modifier and 40 min of residence time (RT). The enzyme treatment of turmeric powder in HSs increased the filtration rate for curcuminoid extraction (gelatinised and native) compared to untreated turmeric powder.