Valorization of Agro-Industry-Rejected Common Bean Grains for Starch Film Development: Advancing Sustainable and Comprehensive Resource Utilization

This study examines the potential use of rejected and discarded grains from the common bean industry as a starch source for producing plasticized films with glycerol. The observed morphological characteristics of starch granules from discarded grains were diverse, with round, oval, and kidney-like shapes and sizes ranging from 7 to 34 µm. We determined the pasting profile: the pasting temperature (GT) fell between 72 °C and 74 °C, while the peak viscosity (P v ) demonstrated a significant rise at 10% and 15% starch concentrations. To better understand pasting behavior, mathematical modeling was employed to predict P v behavior, with an R 2 value of 0.98. All film formulations were successful, yielding transparent, homogeneous, odorless, flexible films with smooth surfaces. Scanning electron microscopy analysis of the films revealed a flawless surface devoid of fissures, cracks, and pores, displaying a rough texture with a consistent structure and some starch granules resembling empty sacks due to amylose and amylopectin leaching. The highest tensile strength was observed with 6% starch and 1.5 mL of glycerol and the lowest with 4.5% starch and 3.9 mL of glycerol. The findings suggest that starch derived from discarded grains from the bean industry has unique characteristics and properties, making it a promising alternative source for intelligent packaging development.