We further compared the antibrowning effect of the ethanol treatment to three previously reported methods: heat shock (hot water), trans-cinnamaldehyde and salicylic acid solution immer- sions. All treatments were able to inhibit enzymatic browning based on the a* value for the first 7 days of storage (Fig. 7). From day
7 to day 14, the heat shock treatment was equally as effective as the
200 mL/L ethanol solution, while the other treatments had less antibrowning effect (trans-cinnamaldehyde) or even stimulated browning (salicylic acid) (Fig. 8). Even though there was not a significant difference on the overall color, the cut surface of lettuce stem discs treated with heat shock displayed a pink ring of dots on day 14. Thus ethanol treatment was the most effective for main- taining quality of lettuce stem discs within 14 day storage period.