The mechanisms controlling heat and mass transfer on frying of beefburgers. I. The influence of the composition and comminution of meat raw material

Heat and mass transfer in minced meat patties (D = 100 mm, H = 10 mm) were studied during frying from the frozen state (−20 °C) to a centre temperature of 72 °C in a double-sided pan fryer. The chemical composition of the meat raw material was varied to study the effect of the water, fat and connective tissue content and the water-protein ratio on the mass transfer (total loss, fat and water losses, shrinkage of the fried patties) and the heat transfer, by recording the time-temperature course at the centre and 2 mm below the surface. The higher initial water content in the meat patties contributed to a faster thawing time in both the core and 2 mm below the surface of the hamburger. The results showed that the higher the shrinkage in diameter of the meat patties, the more fat and total losses, which in turn was related to the amount of connective tissue. This investigation suggests that water and fat losses influence heat transfer and they should be separated. The latter influences mainly the heat transfer in the central core of the thawed beefburgers, whereas in the neighbourhood of crust formation at the surface of the burger, water evaporation losses mainly prolong the frying time. The degree of comminution had no significant effect on the heat and mass transfer.