Modification of Starch Extracted from Cassava with Acidified Ethanol
Ogunmolasuyi A. Martin *
Department of Biochemistry, Federal University of Technology, P.M.B 65, Minna, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aim: The aim of this study was to chemically modify the starch extracted from Manihot esculentus with an objective of gaining insight into the structure and architecture of the native and modified starch.
Study Design: Experimental.
Methodology: Starch from tubers of cassava (M. esculentus) was extracted and chemically modified using a 95% ethanol solution containing 20% HCl at 50°C for 1-4 hours. Structural changes in the native starch and its derivatives were evaluated using colorimeter on treatment with Iodine-KI solution, and the absorbance read at wavelength (λ=470 nm). The gelatinization temperature of the starch was also determined.
Results and Discussion: From the result, absorbance of the acidified ethanol modified starch decreased per hour after treatment with Iodine solution while the weight of recovered derivatives went accordingly. The gelatinization temperature of the modified starch increased with respect to the time taken.
Conclusion: In conclusion, there was an indication that acidified ethanol changed the starch structure and architecture with a corresponding effect on the gelatinization temperature, easy drying and reaction with Iodine solution. The process of modification of the starch gave rise ethyl-O-starch. In addition, starch modified with HCl/ethanol obeys the Lambert-beer law and the rate of hydrolysis of its molecular chains could be monitored and calculated. Therefore, cassava starch modified with acidified ethanol could find applications in food, textile and paper industries.
Keywords: Cassava starch, alcoholysis, gelatinization, Iodine-test, absorbance, time.