The Application of Freeze-Chill Technology to Ready-To-Eat Meal Components

Freeze-chilling involves freezing and frozen storage followed by thawing and chilled storage. A number of ready-to-eat meal components have been studied for their suitability for freeze chilling including, potatoes, carrots, green beans, broccoli, salmon and white sauces. In general, sensory analysis showed that freeze-chilled products were similar in quality to their chilled or frozen counterparts. There were some differences between the freeze-chilled and chilled products in instrumental texture assessment and centrifugal drip loss due to cell damage arising from the freezing step. A freezing rate study was carried out to determine if more rapid freezing could improve texture and drip. Mashed potato was frozen at -30, -60 or -90°C to an internal temperature of -25°C, stored at -25°C for 4 days and then stored at chill temperature (4°C) for a further 4 days. No difference was found in sensory acceptability between any of the treatments. Drip loss was tower (P<0.001) in the chilled mashed potato and decreased with decreasing freezing temperature in the freeze-chilled mashed potato. Freeze-chilling led to a finer texture (P<0.001) than chilling alone but the texture softened (P<0.01) with decreasing freezing temperature. Freeze-chilled foods are potentially more at risk to temperature abuse than chilled products due to the increased amounts of drip water arising from the freezing/thawing steps. A trial was carried out on the effects of different storage temperatures on the quality and safety of freeze-chilled mashed potato. No difference in microbial levels was detected between chill and freeze-chill at any storage temperature but storage time and temperature had effects on total viable counts in both chilled and freeze-chilled products.