Iodine staining does not indicate harvest maturity of 'Ananasnaya' hardy kiwifruit berries

Iodine staining of starch was explored as a harvest index for hardy kiwifruit (Actinidia arguta). Weekly from 2 Sept. to 14 Oct. 2005, the cut surfaces of 20 halved fruit were dipped in an iodine solution and the staining intensity was measured using digital photography and color analysis. Harvest date had a significant effect on percent soluble solids and each of the color readings (L*, a*, b*, and chroma) before and after staining. Fruit harvested later in the season had less starch and thus were lighter in color. However, an observable color difference was only visually apparent weeks after commercial harvest is recommended based on percent soluble solids. Therefore, while the technique can distinguish the conversion of starch to sugar in hardy kiwifruit berries, it cannot be used as a harvest index.