EFFECT OF REPETITIVE IMPACTS ON SUBCUTANEOUS TISSUE DISCOLORATION IN POTATO-TUBERS

From field to shop, table potatoes are exposed to many mechanical forc es (impacts) and are probably impacted often at the same site. We inve stigated the relation between one or more doses of impact energy deliv ered at one tuber site and the resulting volume and depth of discolour ed tissue. Tubers were impacted at a desired rate with a computer-cont rolled pendulum. The tubers were from plants grown at 2 potassium leve ls (i.e. susceptibilities to tissue discolouration) and stored for 3, 5 or 7 months. Splitting of the impact energy into various (up to 9) d oses reduced the volume of discoloured tissue by up to 64%. The depth of tissue damage was less affected (33% reduction) by splitting the im pact energy than the volume was. The volume and depth of discoloured t issue increased with the number of 0.3 J impacts. A decreasing and an increasing order of impact energy caused the same tissue damage. Despi te the experimental simplification and standardization the observed ef fect of the energy and frequency of impacts on the degree of subcutane ous tissue discolouration yielded relevant suggestions for practical p otato handling.