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 11months after maturity and were processed into flours. Chemical and pasting properties of the flours were determined. White trifoliate yam flour at 11months 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 11months. Amylose and starch contents decreased while the sugar contents increased with harvesting periods. Yellow trifoliate yam flour had higher amylose at 10months while the white trifoliate yam flour had higher starch at 9months and sugar contents at 11months. 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 7-9months produced flour with high quality and prevents post harvest losses.