Low Level Soymeal Aerobic Catalyzed Lipoxygenation of Soybean Oil

Low Level Soymeal Aerobic Catalyzed Lipoxygenation of Soybean Oil

CAI Yan

School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, Jiangsu China

Abstract  Lipoxygenase (LOX) can catalyze the oxidation of polyunsaturated fatty acids with cis,cis-1,4-pentadiene to synthesize the corresponding hydroperoxides (HPOD) of conjugated (trans, cis)-dienes. Soybeans are reported to contain LOX in the largest amount in numerous plants.The catalytic performance of low level soymeal (m(soymeal)/m(soybean oil)=10%) in catalyzing the hydroperoxidation reaction using soybean oil as substrate was evaluated, and surfactants as well as ultrasonic wave were introduced to improve the lipoxygenation reaction yield. The optimal conditions for soybean oil were 0.5 g soybean oil in 3.3 mL phosphate buffer solution of pH 6 with 0. 15 mL ethanol as co-solvent reacting for 3 h at 15 ^oC. Under these optimal conditions the yield reached 15%. The addition of surfactants such as CTAB and b-CD reduced the hydroperoxide yield. The employment of ultrasonic irradiation during the lipoxygenation process reached equilibrium after 60 min with the yield of 35%, which could both accelerate the enzymatic reaction and improve the reaction yield.

Keyword:  Soymeal; Lipoxygenase; Soybean oil; Hydroperoxidation