k-carrageenan edible films for beef: honey and bee pollen phenolic compounds improve their antioxidant capacity

Abstract

The physical, antioxidant, and antibacterial properties of edible k-carrageenan films containing bee pollen and honey extracts, as well as their evaluation in vitro and on beef, are reported for the first time. Thickness, tensile strength, elongation at break, puncture force, contact angle, water vapor permeability, UV-screening, thermal analysis, color, antioxidant activity in terms of iron reducing power (FRAP) and antiradical power on DPPH radical, as well as antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas spp., aerobic plate counts were determined. All the extracts significantly increased the physical properties and the hydrophilicity of the films. The use of bee pollen and ulmo honey extracts did not significantly change the films color, whereas the quillay honey extract turned them reddish. Thermal stability of films were not affected by antioxidant bee extracts addition. The antibacterial activity of the films added with the extracts, evaluated in isolation or on beef, was not significantly modified with the use of any of the extracts on any of the bacteria evaluated. On the contrary, the antioxidant and antiradical activity of isolated edible films and on meat increased with the use of all the extracts.