Effect of water kefir grain biomass on chitosan film properties

Water kefir grains (WKG) are frequently used in the production of homemade fermented beverages, and its excess biomass is commonly discarded. This article aimed to assess, for the first time, the effect of WKG on chitosan (CS) film properties, proposing a novel raw material for biobased films production. CS-based films containing 20%, 40% and 60% WKG were prepared. Fourier-transform infrared spectroscopy and X-ray diffraction results indi-cated possible intermolecular interactions between WKG and CS, and a reduction in the film crystallinity. Comparing control and samples containing 60% WKG, it was verified that tensile strength and elongation at break reduced, from 27.17 to 7.67 MPa and from 36.52% to 2.60%, respectively. Water vapor permeability increased from 2.68 x 10-10 to 6.08 x 10-10 g m-1 s-1 Pa -1. However, the incorporation of WKG produced an outstanding UV light blocking effect. In conclusion, considering the set of properties evaluated for all formu-lations, the incorporation of 20% WKG provided the most satisfactory performance, being an easy strategy for valuing this biomass.

Automated summary

Water kefir grains (WKG) were found to have an impact on the properties of chitosan (CS) films, affecting their crystallinity, tensile strength, elongation at break, and water vapor permeability. Among the formulations, the addition of 20% WKG showed the most satisfactory performance.