Effect of Temperature on Glycoalkaloid and Chlorophyll Accumulation in Potatoes (Solanum tuberosum L. Cv. King Edward) Stored at Low Photon Flux Density, Including Preliminary Modeling Using an Artificial Neural Network

Potato tubers (cv. King Edward) were stored at 5, 10, 20, and 25 °C for up to 8 days in either low light (12 μmol of photons m-2 s-1, photosynthetically active photon flux density) or darkness. Tubers were half-buried in potting compost to prevent light reaching the entire tuber surface. After 0, 2, 5, and 8 days samples were analyzed for photosynthetic pigment and glycoalkaloid content. Temperature clearly affected the accumulation of chlorophylls, with 20 °C causing maximal greening. The buried surface of tubers exposed to light also greened, although accumulating only 15−40% of the chlorophyll found in the upper, exposed tissues. However, there was no effect of the temperature or light exposure regimes employed on glycoalkaloid concentrations. Using this data, an artificial neural network was used to produce a preliminary model of the greening process. It was found that this closely resembled the actual results and could estimate intermediate data. It is concluded that there is no biosynthetic link between the low light-induced accumulation of chlorophyll and glycoalkaloids in this commercially important potato cultivar under the conditions described. Keywords: Artificial neural network; carotenoids; α-chaconine; chlorophyll; glycoalkaloids; light; potato; α-solanine; Solanum tuberosum; temperature