Purification of β‐carotene 15,15′‐monooxygenase from pig intestine and its enzymatic hydrolysis of pigment in soybean oil

Summary β‐Carotene 15,15′‐monooxygenase was isolated and purified from the intestinal mucosa of pigs, and then, it was applied to hydrolyse the pigment in soybean oil, and thus, vitamin A fortified soybean oil was obtained. The pig intestinal mucosal protein solution was purified to a specific activity of 2.487 × 10 −4 U mg −1 , maximum reaction velocity ( V max ) of 8.42 × 10 −9  mol/h and Michaelis constant (K m ) of 2.03 × 10 −5   m . The protein solution had a molecular mass of 156 kDa by gel filtration. The sodium deoxycholate concentrations, optimum pH, Tween 40 amount and enzyme amount for vitamin A production in soybean oil were determined to be 6.0 m m , 8.0, 3.0% (w/v) and 0.2 U/mL enzyme, respectively. Under these conditions, β‐carotene 15,15′‐monooxygenase produced 14.65 mg/L vitamin A after 20 h, with a conversion yield of β‐carotene of 33.29% (w/w). Therefore, the nutrients in soybean oil were improved.