Egg yolk hydrolysed granules: Characteristics, rheological properties and applications

• Egg yolk granules have been hydrolysed employing trypsin.
• Peptides have been characterized using chromatographic and electrophoresis techniques.
• Mayonnaises have been prepared with the purpose of making a comparative characterization.
• Mayonnaise made with hydrolysed-lyophilized granules has similar flow behaviour compared to the commercial one.

Given its low-cholesterol content feature, granules from egg yolk can be used as a substitute of the whole egg yolk. However, the functional properties of the granular fraction should be improved. In this sense, hydrolysis of proteins frequently produces improvements in some of its nutritional and technological properties. For that reason, in this work egg yolk granules were treated with a proteolytic enzyme, trypsin (E.C. 3.4.21.4) with the purpose of making a comparative characterization of the products.Results showed that the enzymatic reaction produced a degree of hydrolysis of 12%, being the size of the different peptides obtained and quantified by chromatographic and electrophoretic techniques. Mayonnaises made with these hydrolysed granules resulted more stable to temperature changes between 4 and 20 °C than the one made with non-hydrolysed ones. In the rheological tests carried out, the mayonnaise elaborated with hydrolysed granules has the most similar rheological behaviour to that of a commercial one used as reference. In general, the results obtained suggest that the recipe elaborated with hydrolysed granules had better rheological characteristics than those prepared using non-hydrolysed granules, maintaining the low-cholesterol feature.