Defatted mustard seed meal-based biopolymer film development

Edible films were developed from a defatted mustard seed meal (Sinapis alba) (DMM), a byproduct from the bio-fuel industry. Films were formed by casting DMM suspensions (3-g DMM/100-g suspension) that were treated by high-pressure homogenization (HPH, 138 MPa), ultrasound (400 W, 30 min), or gamma irradiation (10 or 20 kGy), and mixed with glycerol and soy lecithin. Rheological properties, water vapor permeability, water solubility, tensile strength (TS), percentage elongation (%E), elastic modulus (EM), color, and structural properties of film-forming suspensions or films were determined. Films were successfully produced using the HPH-processed suspension with 0.6% glycerol. Rheology results indicated the polymer network structure of the film-forming suspension was loosened by HPH, but tightened by heating at 90 °C. The ranges for the properties of WVP, WS, TS, %E, and EM of the films were 3.4-5.0 g mm/kPa h m², 30.3-34.4%, 1.3-5.5 MPa, 0.9-18.1%, 33.2-294.7 MPa, respectively. L, a, and b by CIELAB coordinates were 73.3-77.9, 0.4-3.5, and 29.5-45.7, respectively. HPH increased TS and %E of the films and decreased EM, whereas the ultrasound and the 20 kGy-irradiation treatments increased %E and decreased EM. The TS and EM decreased and E% increased with increasing glycerol and soy lecithin. DMM is a promising material to produce edible biopolymer films and coatings for food packaging.