The influence of postharvest light treatments on strawberries quality aspects.

MSc-thesis abstract (submitted 6 June 2016):
Strawberry is a highly perishable fruit, rich in vitamin C which is crucial for humans to maintain a healthy immune system.
In this research, we investigated the effect of post-harvest light treatments on vitamin C content in strawberry fruits and fruit weight loss. The interaction of pre- and post- harvest treatments were investigated as well.

Pre-harvest treatments consisted of 50% flower removal and the combination of 50% flower removal and 60% water irrigation. Blue and white LEDs have been reported to improve fruit quality and blue light is expected to extend shelf-life by inhibiting botrytis infection. Post-harvest vitamin C experiment was carried out by applying white LED light (300 μmol m−2 s−1), blue LED light (200 μmol m−2 s−1 and 100 μmol m−2 s−1) on strawberry fruits during cold storage. No interaction was found between pre- and post-harvest treatments.

The results showed that post-harvest light treatments did not increase the vitamin C content due to over ripened strawberry fruits and serious fruit weight loss. The weight loss experiment was carried out using three light sources, white and blue (both with 100 μmol m−2 s−1). At the same light intensity, fruits illuminated with blue light had higher weight loss than fruits in white and dark treatments as a result of higher calyx transpiration under blue light.

It is our recommendation that repeating the post-harvest light treatments on fruits AsA content as function of maturity stage may substantiate the hypothesis that there is a maximum AsA level in strawberries. And weight loss experiments manipulating the calyx area, by varying the position of the calyx towards the light source, by limiting the calyx area, or by applying ABA to close the stomata, might substantiate the hypothesis that weight loss is connected to calyx transpiration.

Keywords: Strawberry; Post-harvest; LED lights; Weight loss; L-ascorbic acid