Mechanical properties of baru fruit (Dipteryx alata Vogel)

Abstract

This paper aimed to verify the influence of moisture content and drying temperature on the values of maximum compression strength for fixed strains (1; 2; 3; 4; 5; 6; and 7 mm), rupture force, and proportional deformity modulus on the baru fruit (Dipteryx alata Vogel) under compression in a natural resting position. Baru fruits with a moisture content ranging from 0.333 to 0.053 (decimal dry basis - db) were used. The fruits were uniaxially compressed between two parallel plates, in the natural resting position, and the nuts were dried at temperatures of 60, 80, and 100 °C. The reduction in the moisture content during drying was monitored using a gravimetric method (weight loss) to determine the initial moisture content of the product and the final moisture content. Based on our results, the compression force needed to deform the baru fruit decreased with increasing moisture content, regardless of the drying temperature. The proportional deformity modulus increased with the reduction of moisture content for all the studied temperatures. The reduced moisture content increased the force required to rupture the baru fruit, regardless of the drying temperature. The rupture forces of temperatures of 60 to 100 °C may be represented by one model.