| Non-meat proteins (pea protein isolate, soy protein isolate, or sodium caseinate), water, and pork backfat were used to form fat emulsions with the ratio of 1 : 4 : 4, respectively. The fat emulsions were then formulated to manufacture frankfurters containing 2% non-meat proteins with 15% fat and 1.5 or 2.5% NaCl. All-meat frankfurters were formulated to contain 15% fat and 2.5% NaCl. All the fat emulsions and the meat batters were tested for rheological properties using steady shear and dynamic oscillation tests. The finished products were tested for thermal stability, water activity, texture, color, purge losses, and microstructure. The fat emulsion with soy protein had a higher storage modulus (G') than the fat emulsion with pea protein or sodium caseinate. The tan delta, which represents the relative viscoelasticity of the fat emulsion, remained relatively constant for the emulsion with soy protein.;The addition of non-meat proteins as PEF (pre-emulsified fat emulsion) in meat batters decreased (p < 0.01) the shear stress, apparent viscosity, and storage modulus (G'). Thermal oscillation tests showed that the addition of non-meat proteins as PEF in meat batters changed the G' pattern but not the gelation temperature. G ' values were similar for meat batters containing soy protein or sodium caseinate with 1.5% or 2.5% NaCl and the all-meat batter at the end of heating (79°C). Reduced NaCl did not influence the rheological properties of the meat batters containing the non-meat proteins in PEF except for a decreased G' on heating for those with pea protein.;Frankfurters with PEF, except those with pea protein containing 1.5% NaCl, had higher (p < 0.01) thermal stability than the all-meat frankfurters. Frankfurters with pea protein were softer (p < 0.01) than the other treatments. Micrographs revealed that many small sized fat globules were physically entrapped within the non-meat proteins, especially those stabilized by sodium caseinate or soy protein. NaCl reduction did not significantly influence the microstructure of the frankfurters with PEF, but resulted in even larger, irregularly shaped fat globules in the frankfurters with pea protein. |
