Influence of dynamic high pressure microfluidization on functional properties and structure of gelatin from bighead carp (Hypophthalmichthys nobilis) scale

Dynamic high pressure microfluidization (DHPM) was applied to treat fish gelatin from bighead carp (Hypophthalmichthys nobilis) scale. The effects of various pressures from 40 to 160 MPa on the functional properties and structural characteristics of fish gelatin were evaluated. The results showed that DHPM significantly improved the emulsifying and foaming properties, as well as the in vitro pepsin digestibility. Surface hydrophobicity of treated fish gelatin was considered to be highly correlated to emulsifying activity with R of.99933. DHPM could not change gel strength and molecular weight distribution of fish gelatin, but decreased its melting temperature with the increased pressures. Micro-structural analysis showed that DHPM endowed fish gelatin with polyporous, rough but uncracked microstructure. Practical applications: In spite of possessing relatively low melting temperature, fish gelatin is a suitable replacement for mammalian gelatin in low-temperature stored foods including milk and yogurt. At this time, surface-active properties including foaming and emulsifying properties are generally the most important factor for ensuring food quality. However, fish gelatin shows relatively weaker surface-active properties, especially emulsifying/stabilizing function. Our results show DHPM is a physical technology to enhance the surface-active properties of fish gelatin. DHPM will be promising to promote fish gelatin for its applications in the food industry.