Fluidized thermal treatment for developing a whole quinoa snack

Recently, quinoa-based products have gain significant attention as ingredients for the food industry. The objective of this work was to chemically characterize a variety of Chenopodium quinoa (var. CICA) and to study a drying-roasting process for the production of a crispy ready-to-eat snack. The experimental work consisted of determinations of thin layer drying-roasting curves for quinoa grains in a fluidized bed dryer, at air temperatures between 80 and 140 ºC during 30 min, with an air velocity of 0.8 m/s. The CICA variety presents protein, fat and carbohydrate contents of 15.3, 7.5 and 70.6% (m/m in dry basis), respectively. The micronutrients, determined by Inductively Coupled Plasma-Optical Emission Spectrometry, were K (9819.2), P (4403.6), Ca (974.6) y Fe (25.3) in mg/kg dry matter. The initial content of saponins was 0.183% (m/m) corresponding to a bitter variety, this value was reduced by washing to 0.108% (m/m), a suitable level for human consumption. However, this process also caused a decrease of 10 to 38% in the mineral content. A mathematical model for local mass balance coupled with a heat balance in spherical geometry, considering variable coefficient of diffusion and shrinkage, was solved by finite differences. For other hand, an activation energy of 35.7 kJ/mol was estimated by solving an inverse problem, utilizing the whole dataset. Predicted temperatures and average moisture contents agreed with experimental measurements. In order to obtain a porous and crispy product, a process time of 10 min at temperatures above 100°C is required.