Storage profiles and processing potential of four potato (Solanum tuberosum L.) cultivars under three storage temperature regimes.

Extended dormancy, low tuber sugar accumulation and light fry color are key traits in the selection of potato chipping cultivars. Within the scope of this three-year study we report on storage characteristics, sugar accumulation profiles and chipping performance of four potato cultivars (Diamant, Lady Rosetta, Hermes and Spunta) under three storage temperature regimes (4.5, 8.5 and 11.0°C). Hermes demonstrated the most prolonged dormancy (197, 112 and 73 days from harvest at 4.5, 8.5 and 11.0°C, respectively), the slowest sprout growth (SPT) and the lowest tuber fresh weight loss. Reducing sugar (RS) accumulation throughout storage was significantly higher in ‘Spunta’ and ‘Diamant’ in comparison to ‘Hermes’ and ‘Lady Rosetta’. A rise in tuber RS content ensued within the first 30 days of storage irrespective of cultivar and temperature. Chip fry color (FCL) demonstrated a highly significant correlation to RS but not to sucrose. Accumulation patterns throughout cold storage suggest sucrose may function mainly as a transient balance in the starch breakdown process but not as a main repository commanding RS formation. Tuber fresh weight loss and sprout growth did not correlate significantly to FCL in any of the cultivars examined. In all profiled cultivars, FCL scores throughout 4.5°C storage were commercially substandard. Significantly superior and commercially acceptable chipping performance was observed at 8.5°C and was further improved at 11.0°C. FCL scores demonstrated a tendency for decline over storage time most pronounced at 4.5°C. ‘Hermes’ and ‘Lady Rosetta’ produced similar, high FCL scores followed by ‘Diamant’ and ‘Spunta’. Chip fry color scores over storage time exhibited patterns inverse to those for RS content. Collective data regression analysis indicated that tuber RS concentrations in excess of 0.147 g/100 g DM may result in substandard chipping performance.