Optimization of formulations for pullulan films containing lauric arginate and nisin Z

- Films were made with various concentrations of pullulan, glycerol, & locust bean gum (LBG).
- Mechanical properties of above films, made with lauric arginate & nisin Z, were evaluated.
- Pullulan films with lauric arginate, nisin Z & LBG (0 or 1 g/L) exhibited the best properties.

Pullulan films containing lauric arginate. alone (LAE) or in combination with nisin Z (LAE-nisin Z), were investigated to determine the effects of the film component(s) on mechanical properties (i.e. ultimate tensile strength [UTS]; Young's modulus [YM]; and elongation at break [EL]). Analyses indicated that pullulan and locust bean gum influenced UTS, YM, and negatively influenced EL of LAE films (P < 0.05). However, pullulan concentrations did not affect UTS of LAE-nisin Z films, but increased YM and decreased the EL values. Glycerol negatively affected UTS for the LAE and LAE-nisin Z films, but positively affected the EL of the films. Locust bean gum significantly decreased EL values of all the formulations. YM also was dependent on the balance of the film ingredients. The films with the best mechanical properties were L150-2.5-0, which contained 2 mg/mL LAE and 320 AU/mL nisin Z, pullulan 150 g/L, glycerol 2.5 g/L, and no locust bean gum, as well as LN120-2.5-1, which contained 2 mg/mL LAE and 320 AU/mL nisin Z, pullulan 120 g/L, glycerol 2.5 g/L and locust bean gum at 1 g/L. The findings of this study may be of interest to researchers who are interested in the mechanical properties of antimicrobial, edible films.