Physicochemical and emulsifying properties modifications of high-pressured egg yolk low density lipoprotein

LAMBALLERIE M.; PUPPO M.C.; SPERONI F.; CHERET R.; ANTON M.

Praga

Congreso; 44th European High Pressure Research Group. EHPRG International Conference; 2006

XX

Egg yolk low density lipoprotein (LDL) are mainly responsible for the emulsifying properties of egg yolk, because of their ability to make up an interfacial film. Moreover LDL are very sensitive to heating, since denaturation and gelation occur from 70 degrees C, and heat denatured LDL do not have any emulsifying properties. Then non thermal stabilization processes are of a great interest to sanitize egg yolk industrial products. To evaluate the effect of high pressure treatment, LDL dispersions were pressured at 200, 400 or 600 MPa, at pH 3.0 and 8.0. Solubility, aggregation, and emulsifying properties (oil droplet size and flocculation) were then analysed. Results put in evidence that high pressure treatment did not modify physicochemical and emulsifying properties at pH 3.0, but that at pH 8.0 LDL were denatured and aggregated without losing their ability to adsorb at the interface between oil and aqueous dispersion, and with a decrease of oil droplets flocculation. Then high pressure treatments do not modify emulsifying properties of egg yolk low density lipoprotein at acidic pH, and lead to an improvement of emulsions stability at alkaline pH. As a result high pressure treatment could be considered to stabilize industrial egg yolk products.