Evaluation of physicochemical characteristics and digestibility of an extrudate with common bean for pigs

Abstract

Objective: To evaluate the physicochemical properties of an extruded feed using bean (Phaseolus vulgaris L.) as a soymeal substitute and to perform pig growth trials, evaluating nitrogen digestibility. Materials and methods: This research was divided into two stages, the first one consisted on the standardization of the extruded feed, where two formulations of bean flour (Pinto Saltillo variety), cornflour (Cafime variety), and soybean meal were evaluated: 20/67/13% and 30/60/10%, respectively. Samples were processed in a single screw extruder at 120-150°C and moisture content of 18-22%. Evaluated physicochemical properties were: expansion index, bulk density, water absorption index, water solubility index, hardness, water activity and color parameters: L*(clarity), a*(red-green chromaticity) and b* (yellow/blue chromaticity). In the second stage, the in vitro dry matter digestibility and fecal apparent digestibility were evaluated using the optimal treatment obtained from stage 1. Results: Optimal conditions for the 20% of bean flour formulation were: Temperature of 124.4°C and moisture content of 18.59%. Extrusion temperature decreased bulk density, hardness, and water activity, but increased L* and expansion index. Moisture content decreased bulk density, water activity, hardness, and a*. In vitro dry matter digestibility was higher for the extruded bean diet in comparison to the control diet (92.33% vs. 85.33%). Conclusions: Results indicated that bean flour is a viable option for animal consumption in terms of nutritional value and good digestibility.

Keywords

• Monogastrics
• Nitrogen content
• physicochemical properties
• temperature
• standardization