FATS WITH IMPROVED OXIDATIVE STABILITY OBTAINED FROM PARTIALLY HYDROGENATED RAPESSED AND SOYBEAN OILS
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Publication date: 1997-12-31
Pol. J. Food Nutr. Sci. 1997;47(4):113-120
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ABSTRACT
Partial hydrogenation of rapseed and soybean oils with Ni catalyst yielded the products of different chemical and physicochemical properties. The consistency of these products at room temperature varied from liquid through semi-solid to solid. Chemical and rheological characteristics of the hydrogenated products were compared with their resistance to oxidation, being determined by storage test and accelerated manostatic method. Despite different content of octadecadienoic acids, both oils showed similar oxidative stability, as measured by the lenght of manostatically-determined induction period, when their relative content of trienoic acids was reduced by hydrogenation to about 3%. The induction period for these oils was one and half as long as for initial oils. The induction period lenghtened three times when linolenic acid was removed from both oils by hydrogenation. Rapseed and soybean oils hydrogenated to iodine values of below 90 and 110, respectively, had the peroxide values of below 10 meq O/kg after 70 weeks of storage at 40C in the dark (thus they were still edible according to the Polish standard), whereas the non-hydrogenated oils had the above peroxide value after about 20 weeks of storage.