Effect of incorporating white pepper (Piper nigrum L.) oleoresin on starch/alginate films

The development of films based on natural components has demonstrated their potential for food preservation. In this research, the effect of the inclusion of white pepper oleoresin (WPO) in a film made from cassava starch and sodium alginate (FWPO) on the antimicrobial, physicochemical, mechanical, optical, and structural properties was evaluated. The films were formulated with different concentrations of WPO (0.0, 0.5, 1.0 and 1.5%). The results obtained indicated that the incorporation of WPO in the film increased the antioxidant activity against the 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH), and an inhibitory effect against Escherichia coli and Staphylococcus aureus bacteria was also observed. Elongation at break (EB), water vapor permeability (WVP), moisture content, solubility, and luminosity (L*) decreased significantly (p < 0.05) with the addition of WPO. On the other hand, the tensile strength (TS), the value of b* (tendency toward yellow) and the opacity increased. Scanning electron microscopy (SEM) images showed a smooth, uniform appearance, and continuous dispersion between cassava starch, alginate and WPO. FTIR spectra showed the interactions between the film components. X-ray diffraction (XRD) patterns showed that the addition of WPO did not affect the structural stability of the films. The results obtained indicate the possible use of WPO in the packaging of food products, contributing to the improvement of food quality and safety.