Mayonnaise, informally called mayo is a cold sauce originating in French cuisine is an oil-in-water (O/W) emulsion with a dispersed oil phase and a continuous water phase containing egg, vinegar, salt, sugar, mustard and water. The oil-water interface is stabilized by egg yolk, which acts as an emulsifier.
Science Behind Mayonnaise formation:
Emulsification: It is the process to force two immiscible liquids to combine in a suspension. Substances like oil and water, which cannot dissolve in each other to form a uniform homogenous solution but the problem are these two unlike substances won’t form an emulsion on their own—so for that, it needs the help of an emulsifier.
So, now the question arises that what is an emulsifier?
Emulsifiers are molecules with a fat-soluble part and a water-soluble part. The fat-loving part sticks to the oil, and the water-soluble part sticks to the water, creating an effective barrier around the droplets thus it is a component that coats the droplets, keeping them separate from each other because when left the droplets will clump together, causing the emulsion to separate. Egg Yolk containing lecithin is an example of an emulsifier.
Ingredients Used for Processing:
Mayonnaise is a thick creamy emulsion of egg yolk, oil, vinegar, lemon juice and seasoning. It works as a base for various sauces like thousand island, tartar sauce etc. Mayonnaise is often used as spreads on sandwiches and burgers, as the creamy base in cold salads, as a dip for French fries and much more
However, mayonnaise from all over the world can have varying ingredients depending on the country of origin. Differences can be seen in 4 choices like the type of oil or emulsifier. The oil type can be changed because of economic reasons while different spices can be used to reflect the culture. The emulsifier used can vary between whole egg (common in USA), liquid egg yolk (common in Europe) and spray dried egg yolk.
Role of different Ingredient on the quality and processing of Mayonnaise
- Oil- It is the main ingredient in mayonnaise and therefore it has a large influence on the quality of the final product. The amount of oil dispersed in the mayonnaise contributes to the viscoelastic behaviour and stability of the product. The oil also impacts the organoleptic properties by providing creaminess and flavour to the mayonnaise. It is therefore important to use an oil with a neutral taste, like rapeseed oil, sunflower oil, or grapeseed oil.
- Egg- In industries pasteurized liquid egg yolk or powdered egg yolk is generally used. Egg yolk is more commonly used as compared to egg white because of its greater emulsifier properties, while egg white also shows some emulsifying ability, but egg yolk is four times more effective. LDL is often referred to as the primary reason for the excellent emulsifying properties.
- Vinegar- Vinegar used in mayonnaise contributes to the flavour of the mayonnaise and it also decreases the pH, helping in the microbiological safety and preservation.
- Salt and sugar- Salt contributes to the flavour and to the stability of the mayonnaise Salt help to neutralize the charges of the proteins (from eggs) so they can adsorb more efficiently to the droplet interface. Sugar also contributes to the flavour of the mayonnaise and is added mainly to counteract the flavour of vinegar.
- Mustard– Mustard contributes to the flavour and colour of mayonnaise. Most of the flavour in mustard comes from the isothiocyanates.
- The first and the second operational speeds may have the same values, i.e. they may be equal. The third operational speed is advantageously higher than the second operational speed
- Mixing into the pre-emulsion denotes a state where the vegetable oil, water and egg ingredient has formed an emulsion.
The diagram below represents the manufacturing of Mayonnaise. Firstly, the egg is supplied into the mixing tank and subsequently, water with sugar already dissolved in it is added. Immediately, the agitator of the mixing tank is switched on and the oil is slowly added into the tank where the pre-emulsion is to be prepared. Then vinegar with previously dissolved salt and lemon juice is added. Once the pre-emulsion is completed, the pump and the mixer is switched on to recirculate the product till the mayonnaise is obtained. When the mayonnaise is prepared, it is transferred into the buffer tank and it is ready for packaging.
But sometimes, due to some factors like the stirring speed, temperature, egg content, egg type and oil content causes changes in the quality of the mayonnaise and even lead to phase-inversion (water-in-oil (W/O) emulsion forms instead of oil-in-water) producing broken mayonnaise, which is characterized by very low viscosity, close to the viscosity of the oil.
Fig 1.1 below represents a good quality made mayonnaise while Fig 1.2 shows a broken mayonnaise.
Fig 1.1 Fig 1.2