Eggs are very good emulsifiers and are used as thickening agents in various recipes. For example, eggs are used to thicken sauces and custards. The drawback is that egg yolk is sensitive to high temperatures and begins to coagulate, leading to loss in emulsification properties. This limits their use in food processing. However, egg yolks can be modified by the addition of enzymes, which makes them retain and improve their emulsifying properties at high temperatures.
Modified Egg Yolks
Modified egg yolks refers to egg yolks to which enzymes PLA2 or MAXAPAL A2 have been added as emulsifiers. PLA2, also called phospholipase A2, is harvested from pig pancreas. PLA2 is available in all mammal tissues and is one of the major irritants found in snake and insect bites. MAXAPAL A2 is an enzyme obtained from a plant source, namely Aspergilus niger, a common mould that grows on fruits. MAXAPAL A2, therefore, is ideal for vegetarians intending to use modified egg yolk products.
Phospholipase A2 or PLA2 is obtained from porcine pancreas and is available ready-made by several manufacturers. PLA2 works by converting 70 percent of lecithin, the component within the egg yolk that contributes to its emulsifying properties, into lysolecithin, which has much better emulsifying properties. MAXPAL A2 is identical in properties to the PLA2 and works in the same manner, but its source is different. MAXAPAL A2 is produced by microbial fermentation of a specific strain of Aspergillus niger. It is a liquid form of the phospholipase A2 enzyme. The process of fermentation results in a highly purified form, which ensures few side effects if at all. Another advantage of purity is that very low quantities are required to achieve desired results.
Modified egg yolk has better heat resistant properties than untreated egg yolks, meaning that they can be used in recipes that require higher temperatures. It is also possible to pasteurize products containing modified egg yolks because of their high degree of stability at elevated temperatures. Pasteurizing, which isn't possible for products with untreated egg yolks, improves the microbial quality of the end product and ensures that the product remains fit for consumption for a longer period. Modified egg yolks also have improved viscosity, which is essential for certain food industry applications.
Enzyme modified egg yolks enhance the thickness of products like mayonnaise. They increase the viscosity of dressings and sauces. Since modified egg yolks add considerable thickness to products, the need for adding synthetic or chemical emulsifiers reduces. These are needed in very small quantities if at all. Enzyme modified egg yolks make desserts creamier and thus tastier.