Browning inhibition of harvested lettuce (Lactuca sativa L.).
Chiesa, A., Carballo, S., Cabot, M. and Filippini de Delfino, O. S.
ISHS Acta Horticulturae 553: 317-320.
2001
บทคัดย่อ
Alternative methods to prevent butt discoloration of butterhead and iceberg lettuce during postharvest handling were studied. Butterhead and iceberg lettuce heads were harvested in commercial field located in Montevideo (Uruguay). Similar sized heads were washed at the stem butt with a sponge impregnated with browning inhibitor solutions, according to the following treatments: (1) control, without antibrowning agents; (2) controlled atmosphere (CA) of 3% O2 and 9% CO2; (3) 5% acetic acid (AcA); (4) 100 g/litre citric acid (CiA); (5) 50 g/litre ascorbic acid (AsA); and (6) 15 g/litre citric acid + 15 g/litre ascorbic acid (CiA + AsA). Heads were placed in boxes, 4 per treatment and lettuce type, and stored for 7 days at 4 deg C and 85% RH and 2 additional days at 18 deg C to stimulate commercial handling in the market. The browning process on the stem butt was evaluated daily for 9 days by monitoring colour changes in the L* and a* values. The a* value in butterhead lettuce during the storage period at 4 deg C did not differ (P<0.05) among treatments (day 7), although AcA, AsA and CiA + AsA showed the best browning-inhibition. AsA and CiA + AsA similarly prevented browning when lettuce heads were transferred to 18 deg C (day 7 to 9), and meanwhile browning increased drastically with AcA treatment. Also, a* values of iceberg lettuce did not differ (P<0.05) among treatments (day 7). CA and AcA were less effective as browning inhibitors when lettuce plants were transferred to 18 deg C (day 7 to 9). Changes in a* value analysis data provide evidence that CiA + AsA was the most efficient browning inhibitor in both lettuce types.