G. Blekas et D. Boskou, ANTIOXIDATIVE ACTIVITY OF 3,4-DIHYDROXYPHENYLACETIC ACID AND ALPHA-TOCOPHEROL ON THE TRIGLYCERIDE MATRIX OF OLIVE OIL - EFFECT OF ACIDITY, Grasas y aceites, 49(1), 1998, pp. 34-37
Minor constituents of virgin olive oil are important for the remarkabl
e stability of the oil in autoxidation, but the exact role and the ext
ent to which each antioxidant factor contributes to the total antioxid
ant effect has not been thoroughly investigated. In this study the rol
e of alpha-tocopherol is explored at various acidity levels and at low
concentrations of ortho-diphenols. A substrate of olive dr triacylgly
cerols devoid of prooxidant or antioxidant constituents was prepared f
rom refined olive oil by column chromatography. To this substrate, sli
ghtly oxidized, the additives (oleic acid. 3,4-dihydroxyphenylacetic a
cid and cc-tocopherol) were added and the stability was assessed by pe
riodical measurements of peroxide values. it was found that free fatty
acids reduce mainly the protective activity of the ortho-diphenol. It
is also concluded that alpha-tocopherd has a synergistic effect with
the ortho-diphenols and contributes significantly to the retardation o
f peroxide formation. This is important for oils poor in ortho-dipheno
ls.