Forced-air, vacuum, and hydro precooling of cauliflower (Brassica oleracea L. var. botrytis cv. Freemont): part I. Determination of precooling parameters

The aim of the present study was to precool cauliflower using forced- air, vacuum and high and low flow hydro cooling methods. The weight of the precooled cauliflower heads (5000 +/- 5 g) was measured before they were placed in standard plastic crates. Cauliflower heads, whose initial temperature was 23.5 +/- 0.5 degrees C, were cooled until the temperature reached at 1 degrees C. During the precooling process, time- dependent temperature and energy consumption were measured, and during vacuum precooling, the decreasing pressure values were recorded, and a curve of time-dependent pressure decrease (vacuum) was built. The most suitable cooling method to precool cauliflower in terms of cooling time and energy consumption was vacuum, followed by the high and low flow hydro and forced-air precooling methods, respectively. The highest weight loss was observed in the vacuum precooling method, followed by the forced-air method. However, there was an increase in the weight of the cauliflower heads in the high and low flow hydro precooling method. The best colour and hardness values were found in the vacuum precooling method. Among all methods tested, the most suitable method to precool cauliflower in terms of cooling and quality parameters was the vacuum precooling method.