Modified starch from cassava (Manihot esculenta Crantz)

Date

11-2006

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Florinia E. Merca

Abstract

PERIN, MARIA LYN G. University of the Philinnines Los Banos. October 2001 MODIFIED STARCH FROM CASSAVA (Manihot esculenta Crantz).

Adviser: Dr. Florinia E. Merca, PhD

Native starch was extracted from cassava (Manihot esculenta Crantz) and was modified by acetylation using acetic anhydride and 3% sodium hydroxide. Physico-chemical properties such as blue value, gelatinization temperature, stability and clarity of paste, water retention capacity and apparent viscosity were determined. FT-IR analysis and SEM were also conducted for both the native and modified starches.

The percent acetylation and degree of substitution of starch acetate were 7.72 ± 0.11 and 0.315 ± 0.010, respectively. Blue value increased after acetylation from 0.077 ± 0.004 to 0.217 ± 0.020. However, gelatinization temperature decreased from 62°C to 78 °C for native starch to 53 °C to 69 °C for starch acetate. Retrogradation tendency increased ,ith storage at 4°C. Water retention capacity also increased with modifications. As the temperature increased, the water holding capacity values also increased. Moreover, the apparent viscosity of starch acetate was relatively higher than native starch. The apparent viscosity values of native starch and starch acetate were consistent during the 30-min test at constant speed at 12 rpm and temperature of 25°C. The native starch exhibited stability at a shorter length of time than the modified starch.

FT-IR spectra of starch samples showed peaks at 1740 cm"' and 1200 cm"' indicating the presence of carbonyl group and C-0 bond. The intensity of peak for hydroxyl groups at 3000-3600cm-1 decreased which indicates replacement by acetyl groups. The size of starch granules of starch acetate relative to the native starch did not change very much. Measurements of starch granules of starch acetate showed relatively smaller granules than native starch which were 14.4 gm and 15.6 gm, respectively

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2006 C4 P47

Document Type

Thesis

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