Physico-chemical evaluation of cocoyam starch
1988
Lauzon, R.D. | Kawabata, A. (Visayas State Coll. of Agriculture, Baybay, Leyte (Philippines). Dept. of Agricultural Chemistry and Food Science)
Starch from red and white cocoyam were analyzed to determine their physico-chemical properties. Granules from red and white cocoyam starch were spherical and semi-spherical in shapes. Both starches showed distinct birefringence and the dark color which correspond to the hylum is located at the center part of the granules. Peak distribution of granular sizes for both starches were at 29.0 mm and 31.3 and their average sizes were 11.66 mm and 12.46 mm both red and white cocoyam starch respectively. Starch of white and red cocoyam belongs to C type. Moisture content of red and white cocoyam starch is 11.49% and 11.99% respectively. Iodine affinities were 4.96 mg/100 and 4.80 mg/100 for both red and white cocoyam starch. Amylose content was 25.43% and 24.62% for red and white cocoyam respectively. P, K, Ca and Mg content of red cocoyam starch were 13.9 mg/100 g, 22.0 mg/100 g, 21.7 mg/100 g and 29.1 mg/100 g while white cocoyam starch were 12.04 mg/100 g, 12.0 mg/100 g, 19.0 mg/100 g and 24.0 mg/100 g for some organic matters analyzed. Red and white cocoyam starch showed similar pattern for swelling power and solubility. The maximum viscosity determined from 6% starch pastes was 300 B.U. for red and white cocoyam starch respectively. Red cocoyam starch retrograde faster than its counterpart. Apparent activation energy for red and white cocoyam starch was 8.49 koal/mol and 6.15 koal/mol respectively at 10 deg C-20 deg C.
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