Orthogonal array design for optimization of phenyllactic acid-sodium alginate blend coating and its effect on the browning and quality of minimally processed lily bulbs.

Abstract

In order to develop active packaging of lily products, we for the first time investigated the effects of phenyllactic acid (PLA) incorporated into a sodium alginate (SA)-based coating on the quality of minimally processed lily bulbs stored at 4 °C for 15 days. L9 (34 ) orthogonal array design showed that the optimal concentrations of PLA, SA and glycerinum were 0.03, 0.03 and 0.05 mol L-1 , respectively, to prepare a blend coating. It was noticed that a PLA-SA blend coating treatment could inhibit browning and maintain the firmness and ascorbic acid of minimally processed lily bulbs. Compared with the control, polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) activities of PLA-SA blend coating treated minimally processed lily bulbs reduced by about 31%, 21% and 29% on the 15th day, respectively. Total phenolic and quinone contents decreased, respectively, by 16% and 55% at the same time. Moreover, PLA-SA blend coating treatment eliminated the accumulation of malonaldehyde (MDA) while inhibiting microbial growth of minimally processed lily bulbs. These results showed PLA-SA blend coating could effectively maintain quality of minimally processed lily bulbs stored at 4 °C, and it might be a prospective technology. © 2018 Society of Chemical Industry.