Performance of packed bed reactor on the enzymatic interesterification of milk fat with soybean oil to yield structure lipids

The interesterification reaction of milk fat with soybean oil mediated by Rhizopus oryzae lipase immobilised on a hybrid organic-inorganic support of polysiloxane-polyvinyl alcohol (SiO2-PVA) was assessed in a packed bed reactor running in continuous flow (45 °C, blend of milk fat and soybean oil 65:35%, w/w). The reactor performance was quantified for different flow rates corresponding to space times (0.5 and 4 h). For each condition, the influence of the space time on the consistency, free fatty acid and solid fat content (SFC, %) was determined. Percentages of reduction on consistency (71.2%) were obtained in relation to the initial blend (1431 ± 42 gf cm−2) and the SFC values (SFC10 °C = 39.6%; SFC20 °C = 20.5% and SFC35 °C = 0.2%) were within the ranges considered ideal for spreads with satisfactory spreadability. The immobilised lipase was stable with respect to its catalytic characteristics, exhibiting a half-life of 39 days.