Effects of minor compounds on hydrogenation rate of soybean oil.

The poisoning effects of minor compounds in soybean oil on the activity of nickel-based catalysts during hydrogenation was investigated. Several soybean oils prepared by different processes were used as the starting oils for hydrogenation. Soybean oil prepared by combining neutralization with degumming and then followed by bleaching leads to a slower hydrogenation rate than an oil prepared by sequential degumming, neutralization and bleaching with activated clay. The selection of bleaching earth used in the bleaching process affected the hydrogenation rate. Soybean oil bleached with neutral clay showed a slower hydrogenation rate. Higher amounts of phosphorus compounds, oxidation products, β-carotene and iron in these oils accounted for the slower hydrogenation rate. Storage of refined and bleached soybean oil greatly affected the hydrogenation rate. An increase in the oxidation products of RB soybean oil during storage was the major reason for the decrease in the hydrogenation rate. [ABSTRACT FROM AUTHOR]