The effect of starch on the pork fat emulsification process was analyzed at the molecular level. The research material consisted of fat-in-water type of emulsions. The experiments were performed on the samples containing 3 parts of water and 1 part of fat. The starch was added in the ratio of 1 : 1, 0.8 : 1, 0.5 : 1, and 0.4 : 1 in relation to the fat content. Analyzed were changes in the molecular dynamics of water in those emulsions during 8 hours from the moment when the system reached the temperature of measurement. The research was performed by a low-field NMR technique. The research accomplished showed that the emulsions were characterized by two components of the T1 and T2 relaxation times. This means that there are two fractions of protons in the system, which relax at different rates, and that the chemical exchange between those two factions of protons is much slower than the relaxation time. The long components (T12 and T22) reflect the relaxation processes of proton fractions associated, primarily, with a biopolymer gel. The values of T12 and T22 increase with the decrease in the starch content in the system much like in gels without fat. It means that this fraction contains much fat. In addition, definite differences were found in the dynamics of molecular water in the systems with low and high starch content. It is related with the forming stages of lamellar structures of fat and with the starch retrogradation. While observing the time-related dependences between the relaxation parameters, it was found that the greatest changes in water binding occurred about 2 to 5 hours after the gel had been prepared.
relaxation times, molecular dynamics, emulsion, low-field NMR, potato starch