TEMPERATURE AND STRAIN RATE EFFECTS ON THE DYNAMIC FAILURE PROPERTIES OF POTATO TUBER TISSUE

We measured effects of temperature and strain rate on the impact properties of potato tubers with the ultimate goal of managing temperature to reduce bruising during mechanical harvesting and handling. Tissue samples from the bud and stem ends of Solanum tuberosum cv. Russet Burbank and Atlantic tubers were loaded to failure under axial compression at 5, 10, 15, and 20°C and strain rates of 20, 50, 80, 110, and 150s–1, using instrumentation developed by the authors. Measurements included failure stress, failure strain, secant elastic modulus, last 50% elastic modulus, toughness (area under the stress-strain curve), impulse load, and shock wave speed. Temperature and strain rate dramatically affected the failure properties of both Russet Burbank and Atlantic tubers. Lower temperature and higher strain rate reduced tissue toughness. The stem end was tougher than the bud end. These results agreed well with impact sensitivity results for whole tubers under similar conditions as reported in the literature. The greater failure strength of Russet Burbank compared to Atlantic agreed with the potato industry observations that Atlantic is more impact sensitive than Russet Burbank.