Development of Modified Instant Starch from Taro (Colocasia esculenta) by Gelatinization

Abstract

In present study an attempt to isolate the starch from Taro (Colocasia esculenta) by adopting standard wet milling extraction process. Isolated starch was then pregelatinized to convert into seven samples of instant starch by autoclaving for different duration ranging from 1hr. to 4hr. with 30 minutes increment span. The seven samples of instant starch so prepared were designated as IS-1, IS-1.5, IS-2, IS-2.5, IS-3, IS-3.5 and IS-4 and isolated taro starch was used as control sample (IS 0). Starch after gelatinization was dried and packed in polyethylene bag. Isolated starch and instant starch samples were analyzed for; resistant starch content (RS %), amylose content (%), water absorption capacity (g/g), swelling power (g/g), solubility (g/g), enzyme digestibility (ED %) and dispersibility (%). The functional parameters of Instant starch were compared with control starch (IS-0). Result showed that the RS content of IS-3.0 was reported to be increased with the span of autoclaving and 3hr was found to be optimum time for making Instant starch with %RS(30.14). Other parameters of IS3, were % amylose content (17.21), swelling power (18.28g/g), solubility (0.099g/g), water absorption capacity (1.72g/g), % enzyme digestibility (59.32) and % dispersibility (68) ,while for isolated untreated starch (IS-0) it were amylose content % (17.83), swelling power (16.02), solubility (0.098), water absorption capacity (1.64), %enzyme digestibility (56.54) and % dispersibility (83). Data reveal that functional properties including (water absorption capacity, swelling power, solubility, and enzyme digestibility) were improved in IS3.0. It was reported that amylose content and dispersibility was slightly reduced on autoclaving owing to degradation and retrogradation of starch. Study concludes that instant taro starch can be prepared by pregelatinizing the starch for 3hr at 15 psi with improved water absorption capacity, swelling power, solubility, enzyme digestibility compared to control starch. Cake prepared from optimum 20% level of IS-3 starch resulted in cake with better volume and texture.