Horchata Processing Waste: A New Source for Starch Film Production

Abstract

Starch films were obtained by solvent casting and thermoprocessing using glycerol as a plasticiser from a new starch source: tiger nut waste from horchata production. The tiger nut starch (TNS) films showed a barrier capacity to water vapour and gases in the typical range of other starch films, such as corn starch (CS) films, with a high barrier capacity to oxygen. The tensile properties of the films were affected by the processing method, exhibiting higher stiffness and resistance to break and lower stretchability than the more common CS films. Thermoprocessed TNS films were less water soluble than CS films, and their solubility was higher than that of cast TNS films. However, all films exhibited similar swelling power. Thermal stability was also similar for all TNS and CS films, showing the typical thermal degradation pattern of starch–glycerol films. Therefore, TNS obtained from horchata production waste can be used to obtain thermoplastic starch films for packaging applications, with characteristics comparable to the most common corn starch films.