Impact of Fungal Extracts on the Physical and Antioxidant Properties of Bioactive Films Based on Enzymatically Hydrolyzed Yeast Cell Wall

Bioactive packaging is gaining interest in food preservation as an alternative to the incorporation of additives to food formulations. Yeast cell wall is a good candidate for the formation of biodegradable films. In this context, enzymatically hydrolysed yeast cell wall (YCW-E) and fungal extracts, containing naphtho-γ-pyrones (NGPs), were used to develop bioactive materials with antioxidant activity. Two types of ethanol fungal extracts from Aspergillus tubingensis G131 were used; a crude (CE*3) and a semi-purified (EP) extract, which presented different antioxidant capacity. Initial degradation temperature of samples with 2% of CE*3 extract were decreased in comparison to the control. Mechanical properties were significantly affected by the incorporation of the fungal extracts, those samples with CE*3 extract presented higher elongation at break due to the presence of melanins, while samples with EP extract showed higher modulus and tensile strength because of the increase in macromolecules interactions product of the hydrophobic character of the extract. Barrier properties were improved due to the low affinity to water of the extract. Antioxidant capacity of films was confirmed by the ABTS method. The addition of fungal metabolites with antioxidant properties to yeast cell wall films is a promising solution for the development of active materials for food contact application increasing shelf life of the products.