Articles
CHANGES IN MICROBIAL AND SENSORY QUALITY OF FRESH PROCESSED UV-C TREATED ‘LOLLO ROSSO’ LETTUCE
Article number
628_95
Pages
753 – 760
Language
English
Abstract
In order to reduce microbial growth and maintain quality of fresh processed lettuce ultraviolet-C (UV-C) radiation has been applied.
Red-pigmented Lollo Rosso lettuce, freshly processed following standard industrial methods, was exposed to UV-C radiation from germicidal lamps before modified atmosphere packaging.
Depending on distance and exposure time (1, 5, and 10 minutes) three intensities 0.81 kJ/m2, 4.06 kJ/m2, and 8.14 kJ/m2 were applied.
Throughout shelf life changes in gas composition within bags were monitored and the effects of UV-C radiation on microbial growth and on quality attributes of the product were determined.
A panel test of 12 people evaluated the sensory quality.
Results showed that microbial growth was inhibited by UV-C radiation at least until day 6 of storage except for lactic acid bacteria.
When UV-C treated product was compared with the control, lower microbial counts for total psychrotrophic, coliforms, and yeast were found.
However only the highest UV-C intensity was efficient to reduce mould growth.
Higher CO2 and lower O2 concentrations were generated within bags containing Lollo Rosso lettuce treated with higher UV-C radiation, which means that treatment increased the respiration rate of lettuce pieces.
Between 0.81 kJ/m2 and 4.06 kJ/m2 treatments and control only slight differences in overall appearance were found.
However, when the highest UV-C treatment (8.14 kJ/m2) was applied, the lettuce tissue became brighter, probably due to the segregation of wax by the lettuce tissue as a protection against the UV-C stress.
Red-pigmented Lollo Rosso lettuce, freshly processed following standard industrial methods, was exposed to UV-C radiation from germicidal lamps before modified atmosphere packaging.
Depending on distance and exposure time (1, 5, and 10 minutes) three intensities 0.81 kJ/m2, 4.06 kJ/m2, and 8.14 kJ/m2 were applied.
Throughout shelf life changes in gas composition within bags were monitored and the effects of UV-C radiation on microbial growth and on quality attributes of the product were determined.
A panel test of 12 people evaluated the sensory quality.
Results showed that microbial growth was inhibited by UV-C radiation at least until day 6 of storage except for lactic acid bacteria.
When UV-C treated product was compared with the control, lower microbial counts for total psychrotrophic, coliforms, and yeast were found.
However only the highest UV-C intensity was efficient to reduce mould growth.
Higher CO2 and lower O2 concentrations were generated within bags containing Lollo Rosso lettuce treated with higher UV-C radiation, which means that treatment increased the respiration rate of lettuce pieces.
Between 0.81 kJ/m2 and 4.06 kJ/m2 treatments and control only slight differences in overall appearance were found.
However, when the highest UV-C treatment (8.14 kJ/m2) was applied, the lettuce tissue became brighter, probably due to the segregation of wax by the lettuce tissue as a protection against the UV-C stress.
Publication
Authors
A. Allende, E. Padilla, F. Artés
Keywords
UV-C irradiation, fresh processed vegetables, sensory evaluation, microbial quality, modified atmosphere packaging (MAP), ¿Lollo Rosso¿ lettuce
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