Enhancement of the oxidative stability of some vegetable oils by blending with Moringa oleifera oil

Blends (20%, 40%, 60%, 80% w/w) of Moringa oleifera oil (MOO) with sunflower oil (SFO) and soybean oil (SBO) were prepared to evaluate the changes in fatty acid (FA) composition, oxidative and thermal stability of SFO and SBO. The blending of MOO with SFO and SBO in proportions of 0-80% resulted in the reduction of linoleic acid (C-18:2) content of SFO and SBO from 67.0% to 17.2% and 56.2% to 14.6% and increase in the contents of oleic acid (C-18:1) from 26.2% to 68.3% and 21.4% to 65.9%, factors of 0.72, 0.72 and 1.27, 1.33, respectively. A storage ability test (180 days; ambient conditions) showed an appreciable improvement in the oxidative stability of substrate oils with increase of MOO concentration, as depicted by the least oxidative alterations in PV, IV and highest increase in induction period, IP, of the MOO:SBO (80: 20 w/w) blend. Each 20% addition of MOO resulted in decreases of PV and IV by factors of 0.84, 0.85 and 0.89, 0.88, respectively, and increases in IP by factors of 1.45 and 1.37 of SFO and SBO, respectively. The heating performance test (180 degrees C for 42 h; 6 h heating cycle per day), as followed by the measurement of polymer contents and total polar contents (TPC), also revealed the MOO:SBO (80:20 w/w) blend to be the most stable. Every 20% addition of MOO in SFO and SBO resulted in reduction of the polymer contents And TPC of SFO and SBO by factors of 0.91, 0.92 and 0.94, 0.94, respectively. On the basis of the present findings, it appears that proper blending of high linoleic oils with MOO can result in oil blends which could meet nutritional needs with improved stability for domestic cooking and deep-frying. (c) 2006 Elsevier Ltd. All rights reserved.