Development and characterization of a novel biodegradable edible film obtained from psyllium seed (Plantago ovata Forsk)

In this study, the physical, thermal and mechanical properties of a novel edible film based on psyllium hydrocolloid (PH) were investigated. PH films were prepared by incorporation of three levels of glycerol (15%, 25%, and 35% w/w). As glycerol concentration increased, water vapor permeability (WVP), percent of elongation (E%) and water solubility of PH films increased whilst, tensile strength (TS), surface hydrophobicity and glass transition point (Tg) decreased significantly. At the level of 15% (W/W) of glycerol, PH films showed the lowest WVP values (1.16 × 10−10 g H2O m−2 s−1 MPa−1), E% (24.57%) and water solubility (47.69%) and the highest values for TS (14.31 MPa), water contact angle (84.47°) and Tg (175.2 °C). By increasing glycerol concentration, PH films became slightly greenish and yellowish in color but still transparent in appearance. This study revealed that the psyllium hydrocolloid had a good potential to be used in producing edible films with interesting specifications.

► We made anedible hydrocolloid film from psyllium without adding synthetic chemicals.
► It had high tensile strength, surface hydrophobicity and glass transition point.
► It had also high flexibility and low water vapor permeability, elongation, and water solubility.
► It has interesting medicinal aspects because of bioactive compounds in psyllium seed.
► It is an environmentally biodegradable with no hazardous and carcinogenic compounds.