Stable antimicrobial emulsion prepared with quaternary ammonium lignin and cinnamaldehyde used for effective postharvest mango preservation

Abstract

With the life quality improving, people's demand for fresh mango is growing rapidly, causing a higher requirement for postharvest preservation. The objective of this study was to prepare a stable and multi-functional emulsion for postharvest mango preservation with cinnamaldehyde emulsified by amphipathic quaternary ammonium kraft lignin, with an excellent dispersion performance. After vacuum freeze-drying and redissolving, no demulsification occurred of the emulsion after heating at 90 °C, the addition of NaCl, 4 cycles of freeze-thaw and 14 days of storage, while the particle size of the emulsion maintained stably in different pH conditions. The DPPH and ABTS free radical scavenging rate were 26.27 % and 95.84 %, respectively. The emulsion presented an excellent antimicrobial ability with the change of the cell membrane permeability and death of bacteria, causing by cinnamaldehyde. The respiratory action, soluble solid and titrable acids consumption of mango coated by the emulsion were inhibited to a certain extent and the freshness life was extended. The emulsion presented no affect in the growth and reproduction of L929 cells with concentration below 50 μg/mL, meanwhile, the properties of emulsion redissolved were not influenced, achieving the goal of long-term storage and transportation, showing great application potential in postharvest mango preservation.