The effect of phytoncide solution treatment on the browning and quality of fresh-cut iceburg lettuce during storage was studied. The treatments were applied as 4 solutions adjusted at 10℃: distilled water (DW) as control; edible ethanol (EE); 1% (v/v) phytoncide essential oil from pine needle diluted with distilled water (DP); 1% (v/v) phytoncide essential oil diluted with edible ethanol (EP).
Fresh-cut lettuce were dipped in the each solutions for 60 seconds and rinsed with distilled water and then packaged with OPP film bag, stored at 4℃ for 12 days.
EP group showed significantly high L* values and low a*, ?E values, browning index, total phenolic compounds, activity of enzymes related to browning (PPO, POD, PAL) and total number of aerobic bacteria. It means that EP treatment is effective to inhibit the browning.
Total number of aerobic bacteria increased over 5.0 log CFU/g, the general acceptance standard of food tolerance limit, in DW and DP group. The number in EP group kept under 5.0 log CFU/g until 9 days of storage. It suggest that EP treatment is effective in control of microbial growth.
Sensory score of color in EP group recorded high value, but the group of EE and EP recorded low scores in aroma and taste as the storage period. Alcohol and phytoncide was vaporized by opening the package for 2 hours, the score of aroma and taste of EP showed no differences with any other groups.
Monoterpenes and sesquiterpenes were major volatile compound, and the content of dl-limonene was the highest (34.58%).
The enzyme activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase (PAL) which are strongly involved in the browning of fresh-cut lettuce were measured. Among the 4 treatments, all the enzyme activity in EP group was the lowest.
Through the above results, the phytoncide essential oil diluted in edible alcohol with 1% solution inhibited the browning and microbial growth in fresh-cut lettuce and it will be useful natural compound in maintaining the quality of fresh-cut produces.