Study On Factors Of Soybean Lipoxygenase Activity And Its Application

Soybean lipoxygenase(LOX) is a kind of newly food additive. But its application is limited because of its low content and its easy inactivation. The factors of LOX activity and its application were studied in this paper.Hexane and supercritical CO₂ extraction were used to degrease fat element from soybean in this paper. The factors of effection on lipoxygenase activity were studied. And it proved that lipoxygenase can improve the white degree of wheat power.The influence of different factors which include hexane additive dosage, reaction times and reaction time were studied. On the basis of one-factor experiments, we selected hexane additive dosage, reaction times and reaction time as the variables, the rate of degrease as indexes, using L₉( 3⁴) orthogonal experiment, the following optimum processing conditions for hexane degrease are obtained. Hexane degrease of soybean were: hexane additive dosage is 3: 1, reaction time is 20min/time, reaction times are 3 times. Using L₉ (3⁴) orthogonal experiment and validation experiment, supercritical CO₂ extraction of soybean are: extraction pressure is 30MPa, extraction temperature is 35℃, flux of CO₂ is 1.0L/h. Degrease of soybean could reduce the content of fat.The mode of burgeon can improve the activity of LOX whereas rubbing reduces the activity. According to results of experiments, degreasing is the best to improve the activity of LOX.The following optimum processing conditions for stability of LOX activity are: reserve 3 days under -4℃, reaction temperature is 25-35℃, reaction pH is 8.0-9.0. Citric acid, 2-mercaptoethanol, cysteine and tea-polyphenol could reduce LOX activity. Then the effect of reducing LOX activity is more when they cooperate with each other.In addition, adding LOX into wheat power could improve its white degree. When additive dosage is 0.8%, the white degree of steamed bread is most.