Potato (Solanum tuberosum L.) nutritional changes associated with French fry processing: Comparison of low-temperature long-time and high-temperature short-time blanching and frying treatments

Six potato cultivars (Fianna, Innovator, Mondial, Navigator, Panamera and Savanna) were evaluated for moisture, colour, oil, protein and mineral element changes associated with French fry processing. Processing involved blanching French fry strips at 75 °C for 10 min (low-temperature long-time [LTLT] blanching) or 85 °C for 5 min (high-temperature short-time [HTST] blanching), before frying them at 160 °C for 2 min (LTLT frying) or 180 °C for 1 min (HTST frying). The results revealed that genotype and the blanching and frying treatments significantly affected the nutritional value of potatoes. Savanna showed the smallest changes, which generally did not differ among treatments, while nutritional changes varied widely in the other cultivars. Cultivars exhibited a reduction in moisture (30-60%), lightness (≤40%), Fe and Al (<150%). However, an increase in oil (8000-19307%), protein (≤110%) and mineral elements, such as Ca, Zn, Cu, P, K, Mg, Na and Mn (<150%), was detected. This increase was mainly attributed to moisture loss associated with the blanching step. HTST blanching resulted in the highest oil absorption in Fianna, Innovator and Panamera, compared to LTLT blanching. These results indicate that the nutritional value of French fries mainly depends on cultivar and the blanching parameters used.