Impacting of thermal energy on the extrusion of dog food

Abstract

The aims of this study will be to verify the influence of thermal energy in dog food by evaluating the parameters of feed extrusion process on the physical characteristics of the kibble. After mixing and grinding the ingredients, diets will be produced adding six amounts of steam in the conditioner. Water input during extrusion will compensate the greater or lesser injection of steam, however the total moisture of the process will be kept the same for all treatments (28% of in-barrel moisture). The extruder parameters as feed rate, screw speed, die open area and the knife speed will not change. Six experimental diets will be produced (treatments) by adding six different amounts of thermal energy in conditioner. Process evaluation and macrostructure of kibbles include the determination of thermal energy application (kJ/kg), specific mechanical energy (kW-t/ton), starch gelatinization degree, specific density, radial expansion, specific length and cutting force (kgf). Data will be submitted to analysis of variance (ANOVA) and means compared by polynomial contrasts (P <0.05). (AU)