Feasibility of Preservative-free Mayonnaise Production by Ultrasonication: Evaluation of Physicochemical and Sensorial Properties of the Product During the Shelf Life

The effects of high-power ultrasound treatment (20 kHz, 750 W, 20 ℃, 5 min) on low-fat mayonnaise were studied to evaluate the oxidation of lipids and fatty acids profile during the 6 months shelf life. The main oxidation parameters including peroxide value, acidity, Thiobarbituric acid, Totox value and fatty acids profile were studied. Also, sensorial properties and emulsion stability at 4℃ and in the accelerated temperature of 50 ℃ in mayonnaise treatments of (without preservatives and with ultrasonication, without preservatives and without ultrasonication, and with preservatives and without ultrasonication) were evaluated during 1, 90 and 180 days after production. The results showed that all samples had good apparent stability and no traces of oil separation were observed. The results of gas chromatography showed that sonication treatment significantly reduced the amount of palmitic acid (7.33 %), alpha-linolenic acid (2.04 %), stearic acid (3.91 %), and poly-unsaturated fatty acids (58.15 %) that in control were (9.44 %, 4.81%, 4.27 %, 59.09 %) respectively, and in contrast, the amount of oleic acid (25.26 %) and linoleic acid (55.91 %) in sonicated treatment increased during the shelf life that compared to the control treatments were (22.47%) and (53.93%) respectively. Also, ultrasonication increased peroxide and acidity value, so that, at the first day, the maximum amount of peroxide value (3.54 meq O2/kg oil) that in control were (2.26 meq O2/kg oil) and maximum amount of acidity of oil (0.19 %) that compares to control were (0.113%) was related to sonicated treatment. Also, the lowest amount of thiobarbituric acid (26.03) and totox value (33.11) which indicates the total oxidation of the product occurred in sonicated treatment, which had a significant reduction that in cintrol were (45.13%) and (118.83%) respectively, these values had an upward trend with increasing storage time.