Fresh weight loss increased rapidly over time and was significantly
influenced by storage conditions (Fig. 3). Light exposure
obviously accelerated fresh weight loss after 5 d storage compared
to darkness. At the end of storage, light and dark storage conditions
resulted in 2.17% and 1.95% fresh weight loss, respectively. Similar
results showed that fresh weight losses of Chinese kale stored in
light and dark conditions were 3.9% and 1.8% at 1 ◦C after 10 d of
storage, respectively (Noichinda et al., 2007).
Fresh weight loss of fresh fruit and vegetables during storage
mainly results from respiration and transpiration. The respiration
releases water and carbon dioxide via oxidation of carbohydrates
and thus reduces dry matter content. However, according
to the present data, no statistical difference in dry matter content
between light (8.9%) and dark (8.6%) storage conditions was
observed. Therefore, in this case, fresh weight loss was probably
caused by the transpiration that occurs with a water vapor pressure
difference between vegetable tissue and the atmosphere. Transpiration
regulation through the stomata is well understood in the
case of leaves (Ben-Yehoshua and Rodov, 2003). Light exposure
has been shown to stimulate stomatal opening and the numbers
of open stomata have been well correlated with the fresh weight