The Effects of High-Pressure Homogenization on Physicochemical and Functional Properties of Gelatin

The aim of the present study was to investigate the effects of high-pressure homogenization (HPH) on the functional, physicochemical, and structural properties of gelatin. Regarding this goal, gelatin was prepared at concentrations of 3, 6, and 9% and homogenized at 100 MPa via one, two, and three cycles. The FTIR results indicated that HPH could destroy hydrogen bonds, leading to the protein unfolding after one HPH cycle. Based on the circular dichroism spectroscopy, the structural packing of gelatin was altered after HPH treatment. Also, the bathochromic shift of gelatin lambda(max) at UV spectra confirmed protein unfolding after one cycle. As a result of this process, the microstructure of gelatin gel was altered, and the pore shape changed from a polygon, a well-oriented shape to an unordered structure. Following one cycle homogenization of 6% gelatin, the emulsifying capacity and stability of the protein were increased by approximately 12 and 600 times, respectively. Under the same conditions, the foaming capacity and stability increased from about 37 to 192% and 85 to 100%, respectively. Conversely, HPH treatment of gelatin resulted in a 40% reduction in gel strength as well as a decrease in elasticity and viscosity. Therefore, HPH will be a promising method to promote the functional properties of gelatin for its application in the food industry.