Evaluation of bioactive multilayer and edible gelatin/xanthan gels crosslinked with Echinacea purpurea for Ricotta cheese preservation

Abstract

In view of enhancing the reliability and performance of active biodegradable and sustainable biomaterials, physically stable layer by layer (LBL) and multilayer films were developed for active food preservation applications. Herein, we propose for the first time, multifunctional and edible biopolymeric packages fabricated from gelatin (Gel), xanthan (Xan) and naturally crosslinked by Echinacea purpurea extract (EPE), which was the active ingredient. As displayed by FTIR and SEM, LBL casting and EPE crosslinking brought about strong dense, and compact composite structures resulting from a significant boost in the intramolecular H-bonding between the composing molecules and layers. Such phenomenon resulted in considerable enhancement in the films mechanical properties, oxygen, water vapor (WV) barriers, and antioxidant capacities at EPE concentration of 3 % as compared to pure gels and Gel/EPE blends. More importantly, EPE release patterns were more controlled in acidic environments than in aqueous conditions over 120 h. Remarkably, multilayer Gel/EPE/Xan treatment reduced impressive 95 ± 0.09 and 80 ± 0.13 % of Staphylococcus aureus and Salmonella enterica, respectively after 48 h. Eventually, the films wrapping succeeded in keeping Ricotta cheese samples properties much closer to those of the fresh ones in terms of weight loss, pH, visual appearance and microbiological analysis. LBL and multilayer films could substantially reduce the bacterial count by high 4.07 ± 0.17 and 3.97 ± 0.23 log CFU/g, respectively under chilled storage over 9 days. By virtue of these positive features, our modified films can be configured as affordable and eco-friendly alternatives for conventional plastic packaging.