Active food packaging: Alginate films with cottonseed protein hydrolysates

Abstract The use of protein hydrolysates (PHs) obtained by the enzymatic hydrolysis of underutilized proteins as active ingredients may be a promising strategy in the development of bioactive packaging. The effects of the incorporation of hydrolysed cottonseed proteins into alginate films were investigated in terms of their physical, chemical, barrier, optical, antioxidant and antimicrobial properties and the release of peptides in two different alginate film food simulants. PH incorporation did not affect the moisture content, biodegradability, solubility or oil barrier properties of the films but did increase the thickness and water vapor permeability. The increase in the PH concentration increased the barrier properties to visible light, and the film colour became darker, reddish and yellowish. The total phenolic content and the antioxidant activity (as tested by the DPPH, FRAP and ABTS methods) also increased. The PH films showed an inhibitory effect against Staphylococcus aureus , Colletotrichum gloeosporioides and Rhizopus oligosporus but not against Escherichia coli . In migration tests in aqueous media, the active films released more than 60% of their peptides in 30 min. Meanwhile, there was a controlled and gradual diffusion of the compounds embedded in the film when fatty foods were simulated. The results showed that alginate films with PHs show promise as active packaging for the preservation of fatty foods.