Pre-cut hot water treatment inhibited the browning of fresh-cut eggplant

The quality and shelf life of fresh-cut eggplant is limited by rapid browning after cutting. Hot water has been reported to be an effective inhibitor of browning of fresh-cut fruits and vegetables. In this study, the browning inhibition effect of pre-cut hot water (45 degrees C for 20 and 30 min) treatments on fresh-cut eggplant was studied. During storage, the changes of fresh-cut eggplant in visual quality, color, polyphenol oxidase (PPO) activity, total phenolic content (TPC), total soluble solid (TSS) content and weight loss were investigated. Browning of eggplant was observed as soon as it was cut, and browning was negatively correlated with L* value. For untreated fresh-cut eggplant, the degree of browning increased with the extension of storage, whereas the hot water pretreatment (45 degrees C for 20 and 30 min) significantly inhibited the development of browning. Moreover, a hot water treatment for 30 min was more effective than 20 min to inhibit browning. The shelf life of heat treated (45 degrees C for 30 min) fresh-cut eggplant was extended from 4 d (control) to 8 d at 2 degrees C. During storage, the PPO activities of control and hot water treated samples first increased and then decreased, whereas TPC showed a decrease, increase and then decrease trends. Compared with the control, heat treatment (45 degrees C for 30 min) significantly inhibited the changes of PPO activity and TPC after 6 and 2 d of storage, respectively. After storage for 8 d, the TSS content of control and heat treatments for 20 and 30 min decreased by 14.4, 16.0 and 19.1%, respectively. Overall, hot water treatment inhibited browning and PPO activity of fresh-cut eggplant, decreased the TPC, prolonged the shelf life, and had no important effects on TSS and weight loss.