Effect of Heat and Tetracycline Treatments on the Food Quality and Acridity Factors in Cocoyam [Xanthosoma sagittifolium (L) Schott]

Abstract

The effects of heat and drug (Tetracycline) treatments on the food quality of cocoyam-tannia [Xanthosoma sagittifolium (L) Schott] were studied. The proximate composition, mineral elements and anti nutritional factors of cocoyam were determined before and after various treatments. Moisture content decreased from 69.8% in the uncooked sample (C₁) to 67.62% in C₂ cooked without drug. The decreases became more significant in various cooked samples C₂ to C₆ with different concentrations of tetracycline. Protein, fat, ash and fibre contents of the raw cocoyam (% dry weight) were 2.83, 0.93, 1.74 and 0.88 respectively. The protein, fat, ash and fibre contents decreased to 1.48, 0.72, 1.70 and 0.76 in the sample cooked without drug (C₂). Significant decreases were observed when samples C₃-C₆ were cooked with 1g (1000mg) of Tetracycline as the values decreased to 1.13, 0.48, 1.33 and 0.57 (% dry wt) respectively. Mineral elements analysis showed general decreases in the cooked samples. There was a 17% reduction in calcium between C₁ and C₆ and similar trend was observed for other mineral elements. A general reduction in the level of anti nutrients was observed after heat and drug treatments. There was an improvement in food quality with respect to the anti nutrients but with decreased values of the desired nutrients. However, there was also a general reduction in the undesirable properties of the cocoyam such as the acridity factors caused by crystal of oxalate when the corms of cocoyam were cooked with and without Tetracycline.