Anti - nutritional factors and mineral composition of pumpkin pulp and functional properties of pumpkin - wheat composite flour for bread preparation

Abstract

Pumpkin pulp is a rich source of vitamins and minerals for human consumption. The objective of this study was to determine the anti-nutritional factors and mineral composition of pumpkin pulp flour (PPF) as well as the functional properties of pumpkin-wheat composite flour used for bread preparation. Wheat flour was supplemented with levels of pumpkin flour (control, 5%, 15% and25%) and bread samples were prepared from these formulations. The mineral analysis of PPF revealed that potassium (K) phosphorus (P) and calcium (Ca) were the predominant minerals with values of 3283.07, 295.75 and 269.61mg/100g respectively. Oxalate, alkaloids and tannins contents were 1625.85, 410.00 and 53.09 mg/100g respectively. It was observed that the water absorption capacity, swelling power and solubility of the composite flours increased as the level of PPF substitution increased. However, the specific loaf volume of the bread samples decreased with   increase   in   the   level   of   PPF   substitution   and   significant   differences (p<0.05)   existed between   the   samples   in   terms   of   their   loaf   volumes   and   specific   loaf   volumes.   Sensory evaluation of the bread samples using a seven point hedonic scale showed that bread with 5% pumpkin flour and control (100% wheat flour) were the most acceptable and they were not significantly different (P>0.05) in terms of the overall acceptability and overall mean scores. It is therefore feasible to produce bread with good sensory characteristics from PPF supplementation to wheat flour. Thus, bread with 5% pumpkin flour substitution can compete with whole wheat bread on the Ghanaian market.