Pasting and Functional Properties of Monodora Myristica (Gaertn.) Seed Flour as Affected by Thermal Processing

Abstract

Monodora myristica (Gaertn.) Dunal is a valuable but underused tropical tree of the Annonaceae or custard apple family. Monodora myristica seeds were dehulled, thermally processed by roasting (10, 20, 30min) and boiling (10, 20, 30min), milled into flour and defatted. Raw (control) Monodora myristica seeds were dehulled, milled into flour, and defatted without any thermal processing. The effects of thermal processing on the functional and pasting properties of flour samples were investigated. Thermal processing had no significant (P ≥ 0.05) effect on the water absorption capacity and swelling power of flour samples. Processing had no significant (P ≥ 0.05) effect on the bulk density of Monodora myristica seed flour samples. Flours processed by boiling exhibited significantly higher (P ≤ 0.05) oil absorption capacity and solubility than the roasted samples. Processing (roasting) did not significantly (P ≥ 0.05) affect the emulsion capacity of flour samples. The roasted flour sample (RO30) had significantly higher (P ≤ 0.05) peak, trough, setback, and final viscosity value among processed flours. Roasted samples had a significantly (P ≤ 0.05) higher breakdown viscosity value than the boiled samples. Thermal processing had no significant (P ≥ 0.05) influence on the peak time of Monodora myristica seed flour. Flour samples from boiled seeds would withstand heating and shear stress compared to other processed samples because of their low breakdown viscosity value. On the other hand, flour from roasted seeds had the highest setback viscosity and would withstand breakdown better than others. Boiled and roasted seed flours of Monodora myristica would be useful in the pasta, noodle, and bakery industries.