Fully waste recycling strategies for improving the accessibility of rice protein film

Although plant protein film is a promising alternative to petroleum-based plastic films, the insoluble nature of some plant proteins still limits its use as a film-forming material. Alkali and thermal treatment are traditional methods to produce film from protein with low solubility, which might pose a risk of caustic burns and harmful substances. Three innovative strategies for the preparation of film-forming precursors were proposed in this study, including a new solvent system using malic acid, a resist folding structure modified by wool keratin, and an electrostatic banded structure by citrus peel pectin. Further, we successfully prepared these three types of rice protein films using glycerin and thermal treatment. The results showed that the film prepared with malic acid has the lowest haze, opacity and water vapor transmission ability. And the film containing wool keratin has the highest mechanical strength and the water resistance. The addition of pectin provided more pronounced whiteness (p < 0.01) and rapid biodegradability, compared with the film produced under conventional alkali conditions. This work demonstrates facile preparations of safer and skin-friendly rice protein film and enlightens broad interests in potential toward the fully ecological-friendly of plant protein film, as well.