EFFECTS OF DIFFERENT LEVELS OF FAT ON RHEOLOGICAL CHANGES AND MICROSTRUCTURE OF MEAT BATTERS DURING HEAT PROCESSING

The effect of differences in fat content (5.3% and 20.8%) on the rheol ogical characteristics and microstructure of meat batters in the cours e of heating was studied. Rheological properties were assessed using n ondestructive measurements (thermal scanning rigidity monitor) and str uctural failure (penetration test) analyses. Microstructure was studie d by scanning electron microscopy (SEM). The influence of fat content on the modulus of rigidity (G) only became evident as gel structures b egan to form, giving higher G values for meat batters the higher the f at content of the sample. As the temperature was raised in the product (between 40 and 70-degrees-C), penetration stress and elasticity incr eased. The work of penetration, on the other hand, increased between 4 0 and 60-degrees-C, remaining steady at higher temperatures. Analysis of the results on the basis of different treatments indicates that an increase in fat content significantly raises penetration stress, elast icity and work of penetration. Increased temperature causes the format ion of a matrix structure typical of heat-induced protein gels, which became compact and determine the formation of stronger, more elastic s tructures. Differences in micro-structure caused by fat content were m ore evident at low temperature (40-degrees-C).