Isolation and physico-chemical characterization of cola starch.

Abstract

Cola nitida (Vent).Schott & Endl, a tropical dicotyledonous tree (family- malvaceae and sub-family - stercullioideae), is a well known plant in the sub-Saharan Africa and renowned for its socio-economic importance in Nigeria and other parts of West Africa. The plant was examd. for the nut's starch compn. and its physicochem. properties compared with corn starch. The starch was isolated using 1% w/v sodium metabisulphite and the proximate anal. (in %) was found to be 4.60 protein, 0.54 crude fiber, 0.54 fat, 1.06 ash, 67.57 total starch and 10.42 moisture. The starch percentage soly. was 7.48% with a swelling capacity of 8.85% and an amylose/amylopectin content of 24:76. It has a pasting temp. of 74.5 °C, gelatinization temp. of 74 °C hydration capacity of 88.59%, emulsion and foam capacities of 5.22% and 1.87% resp. The Rapid Visco Anal. (RVA) of the cola starch has a peak viscosity of 314.42 RVU and the results of the Differential Scanning Calorimetry (DSC) showed peak temp. of 321 °C and onset temp. of 300.7 °C. The photomicrograph indicates that the starch granule is oval in shape, generally small sized with occasional large ones, loose granules with no aggregation and had a mean particle size distribution of 15.33% at 710 μm. The mineral content compn. gave: iron 0.263mg/100g; phosphorus 67.43mg/100g; potassium 4.36mg/100g; calcium 9.40mg/100g; zinc 0.48mg/100g; magnesium 3.78mg/100g; copper (trace), and sodium 1.55mg/100g. Generally, the values obtained for the physicochem. and functional properties compared favorably with that of corn starch, and suggest that cola starch in the unmodified form can be used as a gelling agent, a fat replacer in the food industries where low fat is required and in the manuf. of noodles. It however cannot be used as an emulsifier as a result of its low emulsion and foam capacities. [on SciFinder(R)]