Screening the New Zealand potato germplasm collection for resistance to sugar accumulation during low temperature storage

Abstract

The ability of potato (Solanum tuberosum) cultivars to withstand cool storage without accumulating reducing sugars would allow manufacturers of fried potato products to process potatoes year-round without the development of undesirable Maillard browning compounds. More than 600 potato cultivars and selections held by the New Zealand Institute for Crop & Food Research Limited were screened over three seasons to identify material with resistance to cold-induced sweetening. Potato lines were tested 1-2 weeks after harvest using diabetic glucose test tape, and those with glucose levels below 0.1% (1 g/litre) in the potato juices were stored at 4°C for 2 and 4 months. The effect of any changes in sugar levels on chip colour was then reassessed by frying thin slices in oil and measuring the development of Maillard browning in individual crisps by image analysis. Tubers which failed to produce crisps of an acceptable colour were reconditioned at 18-20°C for up to 4 weeks and retested. Lines with potential to resist cold-induced sweetening or with reconditioning potential were retested for an additional two seasons. † Deceased.‡ Retired. H97069

Tuber components affecting acrylamide formation and colour in fried potato: variation by variety, year, storage temperature and storage time

“…Long‐term storage at a low temperature without a reconditioning period at a higher temperature is the preferable way of storing potatoes if the resulting fried products are to keep an attractive colour throughout the season 10–12. Since potato breeders screen for clones which generate light‐coloured crisps and French fries throughout the storage season at low temperature, the influence of genotype on tuber components will here be presented only at 3 °C.…”

“…Production of a high‐yielding cultivar of potato with an acceptable pale‐coloured fry product after long periods of storage at low temperature is desirable and of high priority in many breeding programmes 12–14. In response to the acrylamide debate it would also be of great interest to breeders and the food industry to know which genetic and/or environmental factors are of greatest importance in the choice of raw material.…”