Soybean oil was hydrogenated by a group of amorphous alloy nanocatalysts of nickel and boron (Ni-B). The Ni-B alloy catalysts showed activities dependent on synthesis conditions. The trans-fat contents in products hydrogenated by one Ni-B catalyst were approximately half of those when a commercial nickel catalyst was used. The Ni-B catalyst had a lower selectivity towards formation of trans-fatty acids but a higher selectivity towards formation of stearic acid than the commercial nickel catalyst. The increases in trans-fatty acids correlated linearly with the increases in C18:1 (oleic and elaidic acids) for nickel-containing catalysts. The incorporation of boron in nickel-containing catalysts increased the selectivity ratio (for forming stearic acid) but did not change the linolenic selectivity. Because of the simplicity to synthesize amorphous catalysts. this work may lead to future development of novel alloy nanocatalysts to synergistically reduce the formation of both trans- and saturated fatty acids in hydrogenated products. (C) 2008 Elsevier Ltd. All rights reserved.