Optimization of aqueous enzymatic method for Camellia sinensis oil extraction and reuse of enzymes in the process

Aqueous enzymatic extraction of Camellia sinensis oil was studied. The results suggested that saponin removal pretreatment assisted by ultrasound was effective in decreasing emulsification and in enhancing the free oil recovery. After 70% isopropanol extraction for 30 min under ultrasound, the residue of C. sinensis seeds was further hydrolyzed with free cellulase and Alcalase for 5 h, and calcium ions were concurrently added during enzymatic hydrolysis (nCa2+: nsaponin = 1:2), and free oil recovery up to 94.14% was obtained. Separate immobilization and co-immobilization of Alcalase and cellulase were performed by alginate entrapment combined with glutaraldehyde crosslinking. Specific activity and recovery of activity for Alcalase and cellulase were acceptable. After immobilization, Alcalase and cellulase exhibited higher activity at a wider pH and temperature range. Reuse experiments of immobilized enzymes were conducted. The deactivation kinetics immobilized enzymes were simulated and half-life of immobilized enzyme was estimated. The results indicated that a magnetic supporter facilitated the recovery of immobilized enzymes from tea seed slurry, and that immobilized Alcalase and cellulase had good reusability.