The Effect of Post Harvest Handling Conditions on the Functional Properties of Orange Fleshed Sweet Potatoes (Impomea batatus)-Grain Amaranth (Amaranthus dubius) Porridge Flours for Lactating Mothers
Abstract
Breast feeding exerts a substantial nutritional and energy demand on lactating mothers. This
result in the need to formulate foods that help meet their increased dietary requirements from
cheap and locally available sources. These foods undergo different post-harvest handling
processes that result in changes in their composition and their functional properties. The
study aimed at determining the effect of curing and storage of OFSP and varying
concentrations of grain amaranth flour on the functional properties of composite porridge
flours for lactating mothers. The water absorption capacity, oil absorption capacity, swelling
power, water solubility index, bulk density, viscosity, gelatinization temperature and
gelatinization time ranged from, 201.2% to 256%, 143.5% to 160.6%, 4.0 to 5.1, 0.66g/mL to
0.67g/mL, 1.8 to 3.7, 136.3 cP to 518.7cP, 69.9 degrees Celsius (℃) to 71.5℃ and 5.0
minutes to 5.1 minutes respectively. Curing and storage of OFSP resulted in a decrease in the
water absorption capacity, swelling power and gelatinization temperature of the flour. On the
other hand, it led to an increase in the water solubility index and the oil absorption capacity of
the flour. Addition of increased amounts of grain amaranth flour led to a decrease in the
water absorption capacity, swelling capacity, water solubility index and gelatinization
temperature of the flour blend. It, however, increased the oil absorption capacity of the flour
blend. Increasing the amount of amaranth flour in combination with curing and storage of the
OFSP caused no significant changes to the bulk density and gelatinization temperature of the
flour. This study showed that sample C70A30 (70% cured OFSP flour and 30% amaranth
flour) as most suitable for making a porridge for lactating women. It has a high water
absorption capacity, a high oil absorption capacity, a high swelling power, a low viscosity, a
short cooking time, and a lower gelatinization temperature. The lower viscosity, water
absorption capacity, and swelling power will lead to the production of a nutrient-dense
porridge in this specific formulation as, higher values in these would lead to a porridge that
holds excessive water, resulting in increased volume but lower energy and nutrient density.
The high oil absorption capacity, on the other hand, will result in improved flavour retention
and mouthfeel. The high water solubility index is associated with improved swelling ability,
which is important for flours intended for porridge applications. Additionally, the lower bulk
density promotes cohesion among flour particles, which leads to increased energy and
nutrient density. Furthermore, the short cooking time and reduced gelatinization temperature
collectively contribute to a porridge that requires less energy during the preparation.