Short term pre-harvest light intensity, carbohydrate and ascorbate effects on keeping quality of lettuce.

MSc-thesis abstract (submitted 11 July 2016): Lettuce (Lactuca sativa L.) is widely consumed and a source of various health benefits. Extending keeping quality of lettuce would make it easier to transport, while decreasing spoilage.
The goal of this study is to improve the keeping quality by using pre-harvest light treatment to increase ascorbic acid (AsA) and carbohydrate levels.

Plants under high and medium light treatments had similar levels of carbohydrates and AsA, and keeping quality. Plants under dark treatment showed reduced AsA, carbohydrate levels, and keeping quality when compared to high and medium light treatments.

This study was not able to conclusively link keeping quality to AsA and carbohydrate levels. However, when correlating final carbohydrate, and total AsA results with shelf life, a positive trend is observed.
Plants under high light treatment were able to retain levels of some soluble sugars and AsA.

Further research with more replication is recommended to confirm or dismiss observed trends.

Keywords: lettuce, light emitting diode (LED), light intensity, ascorbic acid (AsA), L-ascorbate, dehydroascorbic acid (DHA), carbohydrates, post-harvest, overall visual quality (OVQ), keeping quality