Antioxidant effect of tocopherol and TBHQ on oil oxidation over the shelf life of mayonnaise

Common antioxidants in the food industry are usually synthetic compounds، some with proven toxic and carcinogenic natures. The present study examined the effect of tocopherol on oil oxidation in mayonnaise at room temperature over its 6 mo shelf life and compared its performance with common synthetic antioxidants. The treatments were the natural and synthetic antioxidants of 450 ppm tocopherol (MTC) and 150 ppm TBHQ (MTQ) added to plain oil، which was then used to produce mayonnaise. The quality of the products was evaluated by measuring the acidity، peroxide and anisidine values، hexanal concentration، and by sensory evaluation. The results showed that the oil phase in both samples oxidized during the 6 mo shelf life. The acid value، which indicates hydrolytic rancidity، increased for both treatments، but showed no significant difference between treatments over time. The change in peroxide levels in MTC was much less than in MTQ. Tocopherol limited hydroperoxide formation effectively; however، in the last month، the peroxide value for MTC was more than for MTQ. Anisidine value and hexanal concentration are the secondary products of oxidation and showed no significant differences between two treatments. Sensory scores for the two treatments decreased similarly over the course of the shelf life. These results indicate that tocopherol produced no flavor interaction with other compounds in emulsion and showed no adverse effects on sensory characteristics. It can be concluded overall that tocopherol as a natural antioxidant was able to control oil phase oxidation in mayonnaise effectively and can be good substitute for TBHQ in mayonnaise.