Effects of Particle Size of Sucrose Suspensions and Pre‐incubation of Enzymes on Lipase‐Catalyzed Synthesis of Sucrose Oleic Acid Esters

Abstract

AbstractThe effects of high‐speed homogenization, high‐intensity ultrasound, and their combination were evaluated for the reduction of the particle size of sucrose crystals to enhance solvent‐free lipase‐catalyzed synthesis of sucrose oleate at 65 °C. The combination of homogenization and ultrasound greatly decreased the particle size of suspended sucrose crystals in mixtures of oleic acid/sucrose oleate (86 wt% monoester and 14 wt% diester at a ratio of 90/10 w/w) from 88 to 18 μm. The suspension‐based medium was charged to a stirred tank bioreactor that also contained immobilized lipase from Rhizomucor miehei or Candida antarctica (Lipozyme®IM and Novozym® 435, respectively; Novozymes, Franklinton, NC, USA), that was pre‐incubated in oleic acid for several different temperatures (23–60 °C), durations (4–24 h), and stir rates (50–400 rpm, radius of 3 cm), prior to use. The optimal performance was achieved using C. antarctica lipase (83.3 wt% ester, consisting of 46 wt% monoester) in the presence of molecular sieves (18 wt%). The low water concentration (~0.12 wt%) did not affect the activity of C. antarctica lipase.