Evaporated milk processing

Evaporated milk is milk concentrated to one-half or less its original bulk by evaporation under high pressures and temperatures, and usually contains a specified amount of milk fat and solids. Evaporated milk is not sweetened; it is sterilized in cans.

The milk is piped through filters and into the pasteurizers. Here, the milk is quickly heated in one of two ways. The High Temperature Short Time method (HTST) subjects the milk to temperatures of 161 °F (71.6°C) for 15 seconds. The Ultra High Temperature (UHT) method heats the milk to 280°F (138°C) for two seconds.

Evaporation in the dairy industry is boiling off water from the solution. The milk is then evaporated to a specific dry solid concentration. The basic principle involved in operation of an evaporator is heating the milk to a temperature slightly above its boiling point corresponding to the vacuum in the evaporation chamber and separating water vapors from the concentrated mass, simultaneously condensing the vapors in a condenser.

The total dissolved solid concentration achieved in evaporation is critical as it affects the performance of subsequent operations and the quality of the final product. Converting milk into evaporated milk essentially entails reducing the volume of the milk by evaporation and subjecting the concentrate to a sterilizing heat treatment, usually in‐can.

The products to be evaporated are normally heat sensitive and can be destroyed by adding heat. To reduce this heat impact, evaporation takes place under vacuum, sometimes at temperatures the shortest possible residence time.

After evaporation, the milk is homogenized. Homogenization reduces the mean size of the fat globules so that they are distributed uniformly in the milk and do not rise to the top creating a creamy layer.
Evaporated milk processing

History and development of evaporated milk

Evaporated (condensed) milk, like sweetened condensed milk was first developed in the early 19th century and has been available as a canned product for well over a century.

French scientist Nicholas Appert, whose work on food preservation began in 1795, was the first person to evaporate milk by boiling it in an open container and then preserving it by heating the product in a sealed container.

In the 1860s, Borden and Nestle created an evaporated milk preserved in sugar. Patent dealing with preserving of milk after evaporation in a vacuum were granted to Gail Borden by the United States and England in 1856. These patents applied to concentrating milk without addition of sugar.

Milk in the 1850s was considered a child’s drink, highly perishable and likely to carry germs, Evaporating the water and condensing the milk, with addition of sugar yielded a safe, germ free environment resulting in sweet and condensed milk. Borden later added evaporated milk (sugar free) to his production. This new and transportable product became a staple for Civil War soldiers.

In 1884, US patent number 308,421 was issued for ‘an apparatus for preserving milk’ and in 1885, the first commercial evaporated milk plant in the world was opened in a converted wool factory in Highland, IL, where ’evaporated cream’ was manufactured and sold.

By the 1880s, a new technology allowed unsweetened evaporated milk to be produced from a fine curd and to be preserved without sugar.

Borden introduced a formula similar to Mead Johnson’s Dextri-Maltose in the 1920s. In 1927, William M. Marriot, a physician, first recommended the use of evaporated milk in the production in infant formula.
History and development of evaporated milk

Evaporated Milk

Evaporated milk, like sweetened condensed milk, was first developed in the early 19th century and have been available as a canned product for well over a century now.

Condensed and evaporated milk refer to the evaporation of water from milk which makes it more condensed or concentrated. However, in the retail trade, evaporated milk refers strictly to the canned concentrated milk that contains no added sugar.

Evaporated milk is a sterilized milk product containing a minimum of 9% fat and 22% solids-not-fat. Manufacturing process comprises of:

*Standardization – to achieve the required fat:NSF ratio, when normally whole milk is blend with skimmed milk

*Heat treatment – modern plants utilize higher temperature treatments. e.g 120 ° C with shorter holding ties, e.g. 2 min

*Evaporation - The milk is evaporated at low temperature (below 65 °C) to a solids level slightly in excess of that require in the final product.

*Homogenization – necessary to distribute the milkfat, preventing coalescence during in-container sterilization and separation during shelf-life.

*Stabilization and standardization

*Filling and sterilization Though use of evaporated milk has coffee whitener has decline, there is still merit in checking its color reaction and miscibility in coffee. Evaporated milk should impart a rich, golden-brown color to coffee.
Evaporated Milk