Use of bacterial cellulose obtained from kombucha fermentation in spent coffee grounds for active composites based on PLA and maleinized linseed oil

Abstract

Spent coffee grounds have been successfully used as an alternative infusion for kombucha fermentation (spent coffee kombucha, SCK). The obtained by-product of this fermentation consists of a kombucha bacterial cellulose (KBC) matrix. The bacterial cellulose was also fermented in pristine coffee grounds infusion for comparison (coffee kombucha, CK). The bacterial cellulose obtained from both infusion fermentations (SCK and CK) was used as filler in PLA matrix plasticized with a 5 wt% of maleinized linseed oil (MLO). Two different content of SCK and CK (3 and 5 wt%) were introduced in the PLA-MLO matrix to produce a film using a conical twin-screw microextruder to simulate the industrial processing conditions. The resultant bio-based films were studied in tern of morphological, tensile, and thermal properties, UV–visible absorption, water vapor permeability, and wettability. The antioxidant activity of the obtained materials was tested in contact with a fatty food simulant demonstrating antioxidant activity. In addition, disintegrability tests under composting conditions confirmed the compostable character of all films. The obtained results suggest the potential applicability of these bio-based materials obtained by the revaluation of HoReCa waste in antioxidant materials with interest as food packaging or for agricultural uses.