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Qu Y.,Northeast Agricultural University | Qu Y.,Heilongjiang East University | Sun L.,Northeast Agricultural University | Li X.,Northeast Agricultural University | And 7 more authors.
LWT - Food Science and Technology | Year: 2016

In this study, magnetic immobilized phospholipase A2 (PLA2) was used to degum soybean oil such as magnetic particles crosslinked with sodium alginate PLA2 (PLA2-MPCSA), Magnetic chitosan microparticles containing PLA2 (PLA2-MCM), Fe3O4/P(GMA-EDGM-St) PLA2, and Fe3O4/SiOx-g-P(GMA) PLA2, successfully improving the recycling aspect of the degumming process. The highest enzyme loading and enzymatic activity (122.60 mg/g and 1289 U/g, respectively) were obtained using the magnetic immobilized PLA2-Fe3O4/SiOx-g-P(GMA) system. Compared to free PLA2, magnetic immobilized PLA2 had a broader pH-activity profile (pH 4.0-5.5) and activity remained stable between 50 and 70 °C. Enzymatic degumming with PLA2-Fe3O4/SiOx-g-P(GMA) was carried out over 5.0 h with an enzyme dosage of 0.24 g/kg, a pH of 5.0, and a temperature of 55 °C, resulting in residual phosphorus and free fatty acid contents of 9.8 mg/kg and 0.84 g/100 g, respectively. Moreover, magnetic immobilized PLA2 retained more than 80% of its initial activity even after 5 cycles of soybean oil degumming. © 2016 Elsevier Ltd.

Yu D.,Harbin Institute of Technology | Yu D.,Northeast Agricultural University | Yu D.,Collaborative Innovation Food Safety and Nutrition Center | Ma Y.,Harbin Institute of Technology | And 9 more authors.
Journal of Oleo Science | Year: 2014

The aim of this study was evaluation of stability of immobilized phospholipase A2 (PLA2) for soybean oil degumming. Also, the effect of reaction time on residual phosphorus levels was investigated according to the optimum pH and temperature. The free PLA2 and three immobilized PLA2 demonstrated significant differences in optimum operation conditions. pH, temperature and reaction time increased upon immobilization for three different immobilized PLA2 (PLA2-CA, PLA2-CAC and PLA2-CAG). Immobilized PLA2 showed enhanced thermal stability and retained more than 74% of relative activity after 1 h of incubation at 60°C, while the free PLA2 retained only 33%. The three immobilized PLA2 retained 30% to 60% of initial activities after 7 recycles. In particular, PLA2-CAC has more significant profiles in pH, temperature, reaction time and showed the highest remaining activity, thermal stability, reusability. Therefore, PLA2-CAC is a suitable immobilized enzyme for soybean oil degumming process. © 2014 by Japan Oil Chemists' Society.

Hu L.,Northeast Agricultural University | Hu L.,Collaborative Innovation Food Safety and Nutrition Center | Llibin S.,Northeast Agricultural University | Li J.,Northeast Agricultural University | And 7 more authors.
Bioprocess and Biosystems Engineering | Year: 2015

The transesterification of phytosterol and soybean oil was performed using Novozym 435 in supercritical carbon dioxide (SC-CO2). The transesterification reaction was conducted in soybean oil containing 5–25 % phytosterol at 55–95 °C and free-water solvent. The effects of temperature, reaction time, phytosterol concentration, lipase dosage and reaction pressure on the conversion rate of transesterification were investigated. The optimal reaction conditions were the reaction temperature (85 °C), reaction time (1 h), phytosterol concentration (5 %), reaction pressure (8 Mpa) and lipase dosage (1 %). The highest conversion rate of 92 % could be achieved under the optimum conditions. Compared with the method of lipase-catalyzed transesterification of phytosterol and soybean oil at normal pressure, the transesterification in SC-CO2 reduced significantly the reaction temperature and reaction time. © 2015 Springer-Verlag Berlin Heidelberg

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