Light treatments during storage at low temperature might induce both positive and negative
effects on shelf life and quality of produces. For this reason, in this work we examined the effect of
low light irradiance on lamb’s lettuce during storage at a low temperature. Partitioned light
treatments (4 doses per 1h per day; 8 doses per 1h per day; 16 doses per 0.5h per day) showed
positive effects, while continuous light treatments (8h per day) were deleterious. The content of
photosynthetic pigments, energy-linked metabolites and antioxidants was evaluated at the beginning
and after 6 days of storage in comparison with samples stored at 4°C in the dark. The content of
such bioactive compounds was increased or at least similar in samples stored under partitioned light
and at a higher temperature (6°C) when compared to those stored in the dark. We suggest that
continuous light treatments could promote photosynthesis but also cause photo-damage during cold
storage of lamb’s lettuce. However, the photosynthesis under partitioned low light is only partially
activated and so the photo-damage is limited, although the metabolism of green tissues would be
still able to provide carbon moieties for the synthesis of bioactive molecules, thus delaying
senescence. With respect to the samples stored in the dark at a lower temperature (4°C), partitioned
low light treatments at 6°C could contribute to ameliorate the quality of lamb’s lettuce and, at the
same time, allow an energy saving.
