Physico-chemical, Alveograph and Anti-nutritional Properties of Breads Formulated from Wheat and Pawpaw (Carica papaya) Seed Flour Blends

Abstract

The feasibility of partially substituting wheat flour with pawpaw seed (WFPS) flour in bread formulation was investigated. Matured, ripped pawpaw fruits were washed, and the seeds were collected, extracted, dried and milled. Different proportions of wheat and pawpaw seed flour with increasing level of pawpaw seed flour at 0, 2.5, 5, 7.5, 10 and 12.5 % addition in wheat were prepared. Control sample was 100 % wheat flour and its bread. The physical properties of breads and alveograph properties of dough blends were determined. Also, the mineral and anti-nutritional contents of the bread samples were determined using standard procedures. The GENSTAT Statistical Software (version 17.0) was used for data analyses. Physical properties of the bread samples significantly (p<0.05) decreased in oven spring (5.49-2.39 cm), loaf volume (1022.50-901.60 cm3) and specific volume (4.09-3.14 cm3/g) but increased in loaf weight (250.20-288.50 g) with increased pawpaw seed flour addition. Values for dough maximum pressure (91.00-109.50 mm), extensibility (80.50-54.50 mm) and baking strength (255.00-237.50 ×10-4joules/g) significantly (p<0.05) decreased while the ratio of resistance to extensibility increased (1.36-1.66) with increased seed flour addition. The result of the mineral analysis of the breads showed significant (p<0.05) increase in all the mineral parameters determined. High values were recorded in magnesium (143.00-182.50 mg/100g), calcium (252.60-342.60 mg/100g) and phosphorus (73.50-127.30 mg/100g). The anti-nutritional contents of the breads significantly (p<0.05) increased as the level of pawpaw seed flour substitution increased. Tannins, oxalate, Phytate, and Trypsin inhibitor ranged from 1.76-2.68 mg/100g, 0.06-0.28 mg/100g, 0.06-0.29 mg/100g and 1.28-9.71 TIU/100g respectively.