Industrial trial to evaluate the effect of oxygen concentration on overall quality of refined, bleached, and deodorized soybean oil in PET bottles

Soybean oil, owing to its FA composition, is highly susceptible to deterioration by oxidation. The use of nitrogen gas permits the removal of dissolved oxygen and oxygen in the headspace of tanks and bottles. The objective of this work (an industrial trial) was to evaluate the shelf life of soybean oil packaged in polyethylene terephthalate (PET) bottles with different levels of oxygen in the headspace (<0.3, 5–6.5, 7–9, and >15%). The quality of the oil was evaluated during 6 mon. FFA and moisture increased and the smoke point decreased in all experimental conditions, even though the difference between the experiments was not significant. An increase was observed for peroxide value (PV), anisidine value (AV), and specific extinction, and higher increases in these parameters were observed in higher oxygen concentrations. After 180 d, the difference between the PV and AV was significant. According to sensory analysis, the shelf life of the oil increased from 60 to 90, 120, and 180 d as the initial concentration of oxygen was reduced from >15%, 7–9%, 5–6.5%, and 0–3%, respectively. The results demonstrated that shelf life of soybean oil packaged in PET bottles can be significantly increased by using nitrogen to reduce available oxygen in the headspace.