Preparation, optimization and characterization of foam from white-flesh and yellow-flesh cassava (Manihot esculenta) for powder production

Abstract

Cassava foam, another form in which cassava may potentially be used as food, was produced from the pulp of yellow-flesh and white-flesh cassava varieties by whipping with foaming agent (20 %w/w glycerol monostearate colloid, GMS) and stabilizer (sodium carboxymethyl cellulose, NaCMC). Cassava foaming was optimized for concentration of foaming agent, stabilizer and whipping time. Using Box-Behnken experimental design, two responses were measured: foam expansion (FE, %) and foam density (FD, g/mL). White-flesh cassava pulp required 14.97% GMS, 0.51% NaCMC and 2.07 min to give a foam of 52.63% expansion and density of 0.75 g/mL. Yellow-flesh cassava pulp required 14.29% GMS, 0.6% NaCMC and 2 min to yield a foam of 48.25% expansion and density of 0.76 g/mL. Predicted optimal FE and FD were 54.9% and 0.73 g/mL for white-flesh cassava foam, and 49.86% and 0.73 g/mL for yellow-flesh cassava foam, respectively, and are close to validated values. The optimal foams were quite stable after 4 h at 25 ± 2 °C, with low volume collapse of 1.79% and 1.26% for white and yellow cassava foams, respectively. The optimal cassava foams were dried into foam powder. There was significant difference in color values (L*, a*, b*, C*, E*, H*, % W, ΔEyellow−white∗) and total carotenoids content of pulp, optimal foam, and powder of both varieties. Microstructure analysis of the optimal foams revealed round air bubbles and positive skewed distribution of bubble sizes. Foaming and drying significantly reduced total cyanogenic potential in cassava, and may be considered as processing operations capable of reducing cyanogenic potential in cassava considerably.