Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2007
Publication Date: N/A
Technical Abstract: Cold-water fish gelatins are effective emulsifiers without concerns about BSE, incorporating plant essential oils with functional and antimicrobial properties. Release of active compounds and physical properties of films can be controlled and improved by adjusting droplet sizes of micro and nanoemulsions used to cast edible films. To demonstrate this possibility, we investigated the effect of droplet sizes of emulsions prepared with Pollock skin gelatin, oregano oil and lecithin on barrier and sorption properties of microemulsion and nanoemulsion edible films. Emulsions were prepared with 6.67% Pollock skin gelatin, 1% oregano oil, with and without 1% lecithin. A Polytron emulsifier at 15,000 rpm was used to mix the emulsion during 2 min. An M-110Y Microfluidizer (Microfluidics Corp., Newton, MA) was used at 18,000 psi with feed temperature at 20ºC and a flow rate of ~300-400 ml /minute. A Partica LA-950 laser scattering particle size distribution analyzer (Horiba Instruments Inc., Irvine CA) was used for particle size characterization of the emulsions. Water vapor permeability at 25°C, 0/90% RH, oxygen permeability at 23°C and 53% RH, and water vapor isotherms of films at 0-98 % RH by Dynamic Vapor Sorption were also evaluated. Pollock skin gelatin was an effective emulsifier to form microemulsions. It was possible to form nanoemulsions (82.5 nm mean diameter) after three passes in the microfluidizer by using lecithin as co-emulsifier. Addition of oregano oil and lecithin into nanoemulsion films decreased water vapor permeability of Pollock skin gelatin from 1.17 to 0.53 g-mm/m2-h-kPa and oxygen permeability from 0.35 to 0.11 cm3-µm/m2-d-kPa and changed water vapor sorption properties. This study demonstrated that reducing droplet sizes of emulsion fish gelatin films improved barrier properties and affected water vapor sorption characteristics. Cold-water fish gelatins can be used as effective emulsifiers in food systems and for edible films with functional and antimicrobial properties.