Effect of harvesting periods on the chemical and pasting properties of trifoliate yam flour

The effects of delayed harvesting on the chemical and pasting properties of trifoliate yam flour were studied. The tubers were harvested at 7, 8, 9, 10 and 11 months after maturity and were processed into flours. Chemical and pasting properties of the flours were determined. White trifoliate yam flour at 11 months was significantly different (p < 0.05) from other flours in dry matter and fibre contents but the lignin content (1.83%) was not significant different (p > 0.05) from yellow trifoliate yam flour at 11 months. Amylose and starch contents decreased while the sugar contents increased with harvesting periods. Yellow trifoliate yam flour had higher amylose at 10 months while the white trifoliate yam flour had higher starch at 9 months and sugar contents at 11 months. Potassium and sodium were the major minerals found in the yam with higher values in yellow trifoliate yam flours. Peak viscosity and breakdown decreased while the holding strength and final viscosities increased with harvesting periods. Harvesting trifoliate yam tubers at 7-9 months produced flour with high quality and prevents post harvest losses.