Physical, functional and amylograph pasting properties of cocoyam-soybean-crayfish flour blends

Abstract

Four composite flours prepared by combining cooked cocoyam cormels, cooked soybeans, and dried crayfish in the ratios 80:15:5. 70:25:5, 60:35:5. 50:45:5 were
analyzed for selected physical and functional properties. The composite flours were reconstituted into pastes and the relative viscosities of the pastes determined. The
amylograph pasting viscosities of the blends were also measured. Wettability and bulk density (loose and packed) increased with increase in ratio of cocoyam flour in the
mixture. The composite flours were not significantly different in water absorption capacity, their emulsion stabilities were low, and they formed very little and very unstable foams. The composite flour with the lowest ratio of cocoyam has a least gelation concentration of 18% (w/v) flour, whereas the other three had a least gelation concentration of 16% (w/v) flour. There was a very strong tendency for the relative viscosities of the composite
flours to increase significantly with increase in the proportion of the cocoyam flour in the mixture. Amylograph pasting viscosity measurements of the cocoyam-soybean-crayfish composite flours gave maximum (peak) viscosity values ranging from 4 to 75
Branbender units. As the proportion of cocoyam in the mixture increased the peak viscosity increased, whereas an increase in soybean ratio decreased the peak viscosity
but increased the gelation temperature. The setback value of each composite flour was zero.

Keywords: Cocoyam-soybean-crayfish flour blends,
physical , functional , amylograph pasting properties,

Nigerian Food Journal Vol. 25 (1) 2007: pp. 161-170