This may be ascribed to the interruption of the aggregated polymer chains of the matrix bythe oil presence, which supports the slipping of the chains dur-ing film stretching, in confirming the plasticizing role of essential oil (Bonilla et al., 2012). From these curves, mechanical parame-ters: tensile strength (TS), elongation-at-break (EAB), and elasticmodulus (EM) were obtained. The influence of OEO incorporationon TS, EAB, and EM of films can be seen in Table 1. The additionof oregano oil caused a significant decrease (p < 0.05) in TS and theEM, although no significant effect on EAB was observed. Sánchez-González et al. (2009) reported that the addition of tea tree oil(0.5–3% w/w) caused a significant decrease in the TS and EM ofHPMC films, although with no significant effect on EAB. As statedin Table 1, a 58% reduction in the TS values (44.3–18.4 MPa) and72% reduction in EM (1267–354 MPa) were achieved by adding 1.2%(w/v) of OEO to the biocomposite films. According to conventionalstandards, the TS of packaging film must be more than 3.5 MPa (Kimet al., 1995). Thus, the values of 18–44 MPa for fish gelatin–chitosanbiocomposite films are a super value for its use as a disposable pack-aging film. Moreover, the tensile strength and elastic modulus ofthese biocomposite films were comparable with typical packagingplastics, such as low-density polyethylene (LDPE) (15.2–78.6 MPaand 50–100 MPa for TS and EM, respectively), and High-densitypolyethylene (HDPE) (17.9–33.1 MPa and 400–1000 MPa for TS andEM, respectively) (Castilho et al., 2009).