Physical and antimicrobial properties of Gelidium corneum/nano-clay composite film containing grapefruit seed extract or thymol

To improve the physical properties of Gelidium corneum (GC) film, Cloisite Na⁺ and 30B were incorporated into the preparation of the film. X-ray diffraction patterns of the films indicated that a degree of exfoliation and intercalation are formed depending on the type of nano-clays and its concentration and the film structure affects the physical properties of the GC/nano-composite films. Tensile strength (TS) of the GC film was increased by the addition of nano-clays. GC film had a TS of 19.59 MPa for the control, while the GC film having 3% Cloisite Na⁺ or 30B had TS of 27.37 and 26.40 MPa, respectively. Elongation at break and water vapor permeability were also improved by the addition of 3% nano-clays. The physical properties of the film were not improved by the addition of GSE or thymol, but the additions did inhibit the growth of Escherichia coli O157:H7 and Listeria monocytogenes. The results suggest that the nano-composite films containing GSE or thymol may extend the shelf life of food.