Changes in Functional and Pasting Properties of Trifoliate Yam Flour during Storage

Abstract

This work aimed at determining the changes in functional and pasting properties of trifoliate yam flour during storage. Freshly harvested trifoliate yam tubers were processed into flour and stored in sealed low density polyethylene polyester for four months. Functional and pasting properties of the flour were evaluated monthly. Moisture contents ranged from 7.49 to 15.30 %. Moisture contents increased with month of storage. Bulk density ranged from 0.58 to 0.69 g/cm³, water absorption capacity 1.44 to 1.93 ml H₂O/g and swelling index 1.38 to 2.22. The functional properties decreased with length of storage. Flour obtained at the initial period had the least peak viscosity (3180 cP) while the highest value (3338 cP) was at the second month of storage. Storage of trifoliate yam flour improved the holding strength and final viscosities of the flour. Holding strength and final viscosities increased with length of storage. Flour stored at fourth month had higher setback value (1098.5 cP). There were reductions in the pasting time of the flour with storage periods. There were no significant differences (p>0.05) in pasting temperatures of the flours. Storage of trifoliate yam flour for three months is advisable due to high moisture contents which may be detrimental to keeping quality of the flour.

Keywords: Trifoliate yam flour; storage time; pasting properties; functional properties; environmental condition