Thermal energy application on extrusion and nutritional characteristics of dog foods

Abstract

The aim of this study was to evaluate the effects of specific thermal energy (STE) application at the extrusion preconditioning stage on the processing parameters, starch gelatinization, kibble macrostructure, nutrient digestibility, feces characteristics, and palatability of a dog food formulation. Two experiments were conducted, and both used the same dog food recipe. In the first experiment, six amounts of STE were applied by changing steam infusion in the preconditioner to obtain the following discharge mass temperatures: 45°C, 55°C, 65°C, 75°C, 85°C, and 95°C. After evaluating the processing and kibble characteristics, the diets were fed to 36 dogs (six dogs per diet), and nutrient digestibility was determined by total feces collection. Palatability comparisons were carried out with 36 dogs using the two-pan method. Results were analyzed by analysis of variance (ANOVA), and means evaluated by polynomial contrasts according to the STE application (P < 0.05). In the second experiment, three treatments were produced. The extruder was operated with preconditioner mass temperature of 45°C, and the amperage documented. On the sequence, the preconditioner mass temperature was increased to 95°C, and the reduction on amperage was recorded. The extruder feed rate was them increased until a motor amperage equivalent to that of treatment 45°C was observed but keeping constant preconditioner mass temperature at 95°C. Processing and kibble characteristics were evaluated. Results were analyzed by ANOVA with means separated by Tukey's test (P < 0.05). In experiment one, a quadratic reduction of specific mechanical energy (SME) implementation with increasing STE was verified (P = 0.004), with a linear increase in total specific energy application to mass (P < 0.001). Regarding the relationship of starch gelatinization with increasing STE, a quadratic increase after preconditioning and a linear increase in kibbles after drying were verified (P < 0.001). Kibble expansion increased (bulk density, expansion rate, specific length), and hardness decreased with increasing STE (P < 0.001). Apparent nutrient digestibility and food palatability did not change according to STE application. Feces dry matter increased (P = 0.003), but pH and fermentation product content did not change. In experiment two, increasing STE was able to substantially elevate the mass production of the extrusion system while keeping the

Effects of thermal energy on extrusion characteristics, digestibility and palatability of a dry pet food for cats

“…The STE (kW-h/ton) application in the preconditioner and extruder was also calculated for each treatment repetition, combining equations of mass and energy balance (Riaz, 2000). Details of the procedure are provided elsewhere (Pacheco et al, 2018). Finally, the TSE (kW-h/ton) application was obtained by the summation of SME and STE.…”

“…However, despite the importance of extrusion to pet food production, to our knowledge, only one study evaluated energy application and processing conditions to optimize the extrusion of dog foods were found (Pacheco et al, 2018). Furthermore, no publication on energy application to formulations for cats was found.…”

“…Each step plays a specific role in food production to ensure adequate shapes, textures, sanitization and cooking, increasing product shelf life, palatability and nutrient digestibility (Alonso et al, 2000; Gibson & Alavi, 2013; Guy, 2001). However, despite the importance of extrusion to pet food production, to our knowledge, only one study evaluated energy application and processing conditions to optimize the extrusion of dog foods were found (Pacheco et al, 2018). Furthermore, no publication on energy application to formulations for cats was found.…”

Evaluation of antioxidants on oxidative stability and fatty acid profile of poultry offal oil used in the pet food industry

“…Although the effects of the extrusion process on the nutritional values of feed for farm animals are well documented, literature results regarding the effects of extrusion on dry pet food are often scarce (Monti et al, 2016;Pacheco et al, 2018).…”

Cereal extrusion with steam recuperation process

“…Увеличение удельной тепловой энергии путем прямого впрыска пара в предкондиционере снижает удельную механическую энергию, необходимую для желатинизации крахмала и формирования и структурирования гранул экструдата. Более высокая удельная тепловая энергия приводит к увеличению общей удельной энергии, повышению степени желатинизации крахмала, коэффициента расширения гранул и переваримости продукта in vitro [8].…”