Heating and Cooling of ‘Idared’ Apple with Respect to the Duration of the Hot Water Dip Heat Treatment

A research was conducted on the eff ect of heat treatments on the heating and cooling of the ‘Idared’ apple fruit. Th e heat treatment was performed as hot water dip (HWD), where fruit were dipped into water at 50 °C, for two, four and six minutes (HWD 500C 2’, HWD 500C 4’ and HWD 500C 6’, respectively). Th e aim of the study was to determine the eff ect of heat treatments on the warming and cooling on the fruit which was observed by thermographic images recorded every minute for the duration of 12 minutes in total. Th e fruit treated with HWD 50°C 6’ achieved the highest temperature (50.6 0C), followed by HWD 500C 4’ (48.2 0C) and HWD 500C 2’ (44.3 0C). Th e damage to fruit caused by high temperatures (heat damage) was visible only on the fruit treated with HWD 50°C 6’. Th e diff erences in maximal temperature of fruit surface were statistically diff erent among all three exposures for the whole duration of recording, meaning that the duration of the hot water dip treatment signifi cantly aff ects the intensity of fruit cooling aft er heat treatment.