Effect of rosemary leaves on autooxidation of purified corn and soybean triacylglycerols

ABSTRACT

Antioxidant activity of dry ground rosemary [Rosmarinus officinalis L.] leaves of particle size corn and soybean oils triacylglycerols [CO TAG, SO TAG] was studied at 60 +/- 1 °C in dark. The systems were purified corn or purified soybean triacylglycerols without antioxidants [controls], with 100 micromole alpha tocopherol, 100 micromole butylated hydroxyanisol [BHA], 100 micromole butylated hydroxytoluene [BHT], 100 micromole tertbutyl hydroquinone [TBHQ], 100 micromole Trolox, 180 ppm carnosic acid and 0.2% ground rosemary leaves [filtered and non-filtered]. Oxidation was followed up by ferrous oxidation [Thiocyanate method] and hexanal determination. Diffusion of antioxidant constituents from rosemary into oil was monitored by radical scavenging method using alpha, alpha'-biphenyl-beta-picrylhydrazyl [DPPH]. Rosemary showed to be an effective antioxidant bearing plant especially with oils containing high percentage of polyunsaturated fatty acids. In CO TAG the order of decreasing hydroperoxide inhibition was Trolox >/= rosemary> TBHQ> carnosic> alpha-tocopherol> BHA. In SO TAG the inhibiton order was rosemary > Trolox> TBHQ>carnosic>alpha-tocopherol>BHA