Effects of torrefaction on some physico-mechanical and organoleptic characteristics of maize flour blended peanut patties rolled into sticks in Benin

Abstract

The cake, from peanut seeds oil-extraction, is classically used for cattle feed manufacture and fertilizers. It may also well be valorized as crispy patties for human food. Several variants of peanut patties, "kluiklui", rolled into sticks, are very prized in Benin. This passion for patties, coupled with fairly high price of groundnut seeds, incited patties producers to innovative and ingenious manipulations. From then, crude or roasted maize flour was incorporated to replenish many groundnut variants patties. This article is devoted to study influences of applied torrefaction to maize grains giving added flour during formulation of fried groundnut's defatted dough into different variants on some physical (residual humidity, apparent density, volume expansion rate), mechanical (fracture strength) and organoleptic (color, crustiness, taste) properties of the produced patties. The results showed that torrefaction causes significant decrease of residual water content, volume expansion rate and breaking strength, making corresponding patties less crusty and less well-liked by consumers as proven by realized tasting results. However, torrefaction of maize flour also induced increase of the patties apparent density. Nevertheless, the latter was less affected in comparison with the previous three cited characteristics. The groundnut patties variants, blended of maize flour at respective rates of 5% and 10% (weight-in-mix), were the most affected by torrefaction process relatively to recorded feeble breaking strength values and thus, the best prized by patties consumers.

Keywords: maize seeds, bulk density, expansion rate, breaking strength, crustiness, taste.