Moisture Sorption Studies of Extruded Maize/Soybean Snacks

Abstract

Moisture sorption studies of two variants (sweet and spiced) of extruded, ready to eat maize/soybean snacks was done to ascertain their behaviour, integrity, stability and acceptability post production, as these are dried products with a tendency for moisture uptake. The snacks were exposed to relative hunidity conditions of 11 – 92% at 27 o C, for a period of four weeks. Weighing was done weekly until equilibrium was attained. Colour and other deterioration changes were also observed. It was found that both variants were similar in composition and behaviour. Critical moisture content in the sweet variant was 9.4% (corresponding to an equilibrium RH of 44%) and 11.9% in the spiced (corresponding to an ERH of 56%) implying the maximum moisture content permissible for product acceptability. The Brunauer - Emmett - Teller (BET) monolayer moisture content was found to be 5.56 % for the sweet sample and 5.88% for the spiced, indicating the minimum moisture levels to which these samples can be dried economically and also at which the snacks have the most desirable physico-chemical attibutes and maximum stability with respect to rancidity