다양한 식용유로 제조한 물속 기름 에멀션의 자동산화 안정성 평가

초록

Purpose: This study was conducted to assess the autoxidative stability of oil-in-water (O/W) emulsions (4:6, w/w) of various edible oils manufactured by different processing methods. Methods: Emulsions consisted of commercially available edible oils (40 g) and citrate buffer (pH 4.0, 60 g) with addition of xanthan gum (0.35 g) and egg yolk lecithin (35 mg), and were stored in the dark at 40°C. The edible oils included refined olive oil (ROO), extra virgin olive oil without refining (EVOO), refined, bleached, and deodorized soybean oil (RBDSO), cold pressed oil of unroasted sesame seeds (URSO), roasted sesame oil (RSO), and RBD canola oil (RBDCO). Lipid oxidation of the emulsions was spectrophotometrically evaluated based on the hydroperoxide contents and p-anisidine values (PAV). Total contents of polyphenols in the emulsions were determined by spectrophotometry. Results: The hydroperoxide content and PAV increased with storage time due to lipid oxidation. The emulsion with URSO, ROO or EVOO showed higher hydroperoxide contents than the emulsion with RBDSO or RBDCO during storage mainly due to higher initial values. However, the oxidation rate was lower in the emulsion with EVOO or RSO compared to ROO and URSO, respectively. The emulsion with RBDCO or RBDSO which was fully-refined oil showed higher oxidation rates than those with olive or sesame oils. This suggests higher oxidative stability of the emulsion with olive or sesame oils despite their higher initial value of lipid oxidation, possibly due to the higher quantities of polyphenol compounds and their stability in these oils. The Maillard reaction products could be additional contributors to the oxidative stability of the RSO emulsion. Conclusion: The results suggested that the variation in autoxidative stability of O/W emulsions with different oils could be attributed to more hydrophilic polyphenol compounds rather than hydrophobic tocopherols. Thus, EVOO or RSO could be a good choice of edible oil for the preparation of an O/W emulsion with high lipid oxidative stability.

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