Abstract
Potatoes were baked for up to 60 min in a conventional fan‐assisted oven. Temperature profiles within the potato tubers were determined both by direct measurement and by following the inward progress of starch gelatinisation, which occurs at 65 °C. Temperature profiles with time were S‐shaped and about 30 min was needed for the centre to reach 100 °C. From the nature of the temperature profiles, long potato tubers will cook faster than round tubers of the same weight, and a varietal ‘shape factor’ was defined to quantify this effect. The slow temperature rise, compared to other forms of cooking, was due to evaporative cooling. Moisture loss was linear with time after an initial lag and reached 15–20% of the mass of the potato after 1 h of cooking. Approximately half of the moisture was lost from the outermost layer of the potato under the periderm, leaving behind a dried layer of flesh that appeared to restrict water transport and, unlike any other part of the potato, could exceed 100 °C. This has consequences for the thermal development of flavour compounds as well as for perceived texture.
© 2002 Society of Chemical Industry