Effect of Processing and Storage Parameters on the Oxidative Deterioration of Oil-in-Water Emulsions

Abstract

The effect of storage temperature, pH, and homogenization pressure on the oxidative deterioration of Tween 20 and sodium caseinate sunflower oil-in-water emulsions was studied by monitoring conjugated dienes (CD), lipid hydroperoxides (LH), and thiobarbituric acid reactive substances (TBARs). CD increased linearly with storage time, and the rate constant was temperature dependent according to the Arrhenius equation with an activation energy equal to 37.5 kJ mol −1 . The increase in LH and TBARs with temperature (5-60°C) was in good agreement with CD variation. Tween-stabilized emulsions oxidized faster as pH increased from 3 to 7, whereas a different behavior was observed in emulsions stabilized with sodium caseinate or a mixture of both emulsifiers. A change of homogenization pressure (30-900 bars), reflecting variation of emulsion average droplet size, had no effect on the oxidative stability of the emulsions.

Effect of Droplet Size on Autoxidation Rates of Methyl Linoleate and ^|^alpha;-Linolenate in an Oil-in-Water Emulsion

“…Conversely, the rate constant for the last half of the methyl α-linolenate autoxidation was smaller for emulsions with larger oil droplet sizes. Roozen et al 12 and Dimakou et al 14 have reported that the autoxidation of linoleic acid and sunflower oil, respectively, containing linoleoyl residues did not depend on oil droplet size in O/W emulsion systems, findings similar to our results. Therefore, in the case of n-6 polyunsaturated fatty acids (2) and (4), respectively.…”

Mass Transport Phenomena in Lipid Oxidation and Antioxidation

“…As such, surface-active LOOHs could concentrate at the oil-water interfaces of bulk oils, oil-in-water emulsions, or membrane systems. Indeed, several authors have reported the presence of LOOH at the emulsion droplet surface (Dimakou et al 2007;Mancuso et al 2000;Mei et al 1998a,b;Nuchi et al 2002;Yoshida & Niki 1992). In membrane systems, LOOHs float on the LDL surface (Ingold et al 1993).…”

Luminol Chemiluminescence Profile of O/W Emulsions during Thermal Oxidation

“…8 Briefly, 700 μL of distilled water and 2 mL of TBA solution (prepared with 15 g trichloroacetic acid, 0.375 g TBA, 1.76 mL 12 M HCl and 82.9 mL H2O) were added to 300 μL of the sample solution, and vortex-mixed for 15 s. The mixture was heated in a boiling water bath for 15 min and then cooled at room temperature for 10 min. The sample was centrifuged for 15 min at 650g and the absorbance of the supernatant at 532 nm was measured.…”

“…The incubation temperature of 60 C was adopted according to the literature. 5,8 The emulsions were prepared with 0.2% w/v oil and 0.02% w/v Tween 20. As shown in Fig.…”

“…4 Several factors influence the rate of lipid oxidation, such as the fatty acid composition, temperature, the pH and ionic composition of the aqueous phase, the type and concentration of antioxidants, and the characteristics of the lipid droplets. [4][5][6][7][8] Several methods have been used to estimate the oxidation of lipid in an emulsion, including conjugated dienes, 5 the peroxide value (PV), 7 thiobarbituric acid (TBA) assays 6,8 and chemiluminescence (CL) with luminol. [9][10][11][12][13][14] Of these, the CL method has the advantages of sensitivity, simplicity, and rapidity to monitor the oxidation degree.…”