Pickering emulsions stabilized by chitosan-zein-lipase particles for interfacial catalysis.

Lipase is widely used in the food industry, but its catalytic efficiency is limited by the insufficient enzyme-substrate contact. To address this issue, chitosan-zein complex particles immobilized lipase (CZPs-lipase) and the corresponding Pickering emulsion catalytic system (PEC) were fabricated. The results showed that the incorporation of zein increased the three-phase contact angle of the particles and decreased the particle size, facilitating lipase immobilization. However, the reduced ζ-potential of the particles was unfavorable for the lipase immobilization by electrostatic adsorption. As a compromise, the maximum immobilized lipase activity was obtained at a chitosan:zein mass ratio of 1:2 (CZPs-lipase). In addition, the PEC stabilized by CZPs-lipase had a significantly (P < 0.05) smaller particle size than that stabilized by chitosan-lipase particles. Consequently, after 120 min of reaction, the hydrolysis rate of p-nitrophenol palmitate in the PEC stabilized by CZPs-lipase was 1.66 and 3.67 times that of the free lipase emulsion and the free lipase biphasic catalytic system, respectively. Meanwhile, after 180 min of reaction, the hydrolysis rate of corn oil and soybean oil in the PEC reached 75.68 ± 1.85 % and 96.27 ± 2.26 %, respectively, significantly (P < 0.05) higher than that in the free lipase emulsion. After five cycles, the relative hydrolysis rate remained at approximately 85 %. This efficient PEC has considerable potential for applications in the food industry.