3. Effect of films on oxidative stability of sunflower oil
Oxidation of polyunsaturated fatty acids drastically affects food quality (Berton-Carabin et al., 2013). Active packaging incorporated with natural antioxidants represents a promising preservation technique to extend food shelf life and prevent this problem. The Determination of peroxide value (PV) in one of the most important methods to evaluate the quality of vegetable oils, and its measurement indicates the primary oxidation status of the oil, which can easily lead to further rancidity stages (Pizarro et al., 2013; Yanget al., 2014).
The initial PV value of commercial sunflower oil was near 2.2 mEq/kg. The results of PV are shown in Table 5. Oil kept in closed plastic bottles and in open glass Petri dishes underwent a similar extreme oxidation process during the time of the experimentand reached PV values over 270 mEq/kg on day 28. It is important to note that during the time of the experiment, PV values for oil packed in films Test 3 and Test 10 did not exceed 10 mEq/kg, which is the recommended limit for refined oils to be considered fresh (Codex-Alimentarius, 1999).