The Effect of Freezing Rate, duration of Frozen Storage and Comminution on the Dielectric Properties of Pork
The objective of the current study was to evaluate the impact of comminution and freezing (rate and duration of storage) on the dielectric properties (e’ and e’’) of meats measured at frequencies used for cooking (i.e. radio frequency (RF) (27.12 MHz) and microwave (MW) (915 and 2450 MHz)). Temperature rises (Delta T) were also measured following standardised RF or MW cooking protocols (90 s at 450 W). A factorially designed experiment was conducted and results suggest e’ and e’’ were generally though not always significantly lower in more highly comminuted samples. At MW frequencies in meats with added ingredients, frozen products generally had lower e’ and higher e’’, while slow frozen meats with no added ingredients had higher e’ values at MW frequencies. Duration of frozen storage had some influence on dielectric properties which varied depending on the product and freezing rate. Overall, the impact of comminution and freezing on Delta T was relatively minor.