If you have never heard of lyophilization, this article is for you. The term ‘lyophilization’ describes a process which produces a dry product. It is widely used in the pharmaceutical industry, as well as in the food and technological industries.(1) But what is it and why do we use it? Keep reading to find out.
What is lyophilization?
Lyophilization, or freeze-drying, is a process in which the subject (for example fruit) is first frozen, so that the water in it turns to ice, which is then removed through a two-part drying process.(1) The first part – or primary drying, is called sublimation, followed by secondary drying – a process called desorption.(1) The main principle involved in lyophilization is sublimation – a process where water passes directly from the solid state (ice) to the vapor state, without passing through the liquid state.(1) This leaves only solid, dried components of the original product.(1) It is followed by desorption, where the bound moisture left over in the product – which can be as high as 7%-8%, is reduced to optimal levels through warmer temperatures.(1)
Where can we use lyophilization?
One of the main industries that uses it is the food industry. Lyophilization preserves food and makes it very lightweight.(1) It minimizes the changes in the shape of the product, allowing for minimal shrinkage.(2) The low temperatures used in the process also contribute to preserving constituents such as minerals and vitamins, as well as enable the food to retain its original flavor and aroma.(2) Lyophilization is typically used in the production of foods that are perishable and difficult to preserve as fresh products – such as fruits, vegetables, noodles, pasta, shrimp, meat and fish.(2) It is also used to preserve food for astronauts, for example, freeze-dried ice cream.(2)
Moreover, it is widely used in pharmaceuticals in order to improve the stability and long-term storage of drugs that are heat-sensitive or contain biological components, such as vaccines and other injectables.(1) Removing water from the material allows it to be easily stored, shipped, and later reconstituted to its original form.(1)
It is further used in the technological industry, to make products more stable or easier to dissolve in water for subsequent use, or as a late-stage purification procedure that removes solvents.(1)
But that is not all, lyophilization also has a number of other uses. For example, the Document Conservatory Laboratory at the United States National Archives and Record Administration (NARA) have studied freeze-drying as a recovery method for water-damaged books and documents.(1) It can also be used in bacteriology, to conserve special strains.(1)
What are its advantages and disadvantages?
Lyophilization has many advantages – such as minimizing chemical decomposition, it allows for water removal without excessive heating, enhances the stability of the product in a dry state and is more compatible with sterile operations.(1)
But as with all things, it does have its disadvantages, the main ones being the prolonged handling and processing time(1) and high treatment costs.(2)
Lyophilization is a complicated process used in several industries. Chances are, you have at least one product that has gone through this process in your home right now, be it a healthy food product containing lyophilized fruit, such as our Tiny Giant meals, certain pharmaceutical products, or other items. It is not always easy knowing when a product has gone through lyophilization in the pharmaceutical and technological industries, but when it comes to food? Choosing items that contain lyophilized fruit, vegetables, or other lyophilized ingredients, is a healthier and tastier decision than choosing products that contain, for example, conventionally dried food items.
- Gadre Harish, Borse Tushar, Ola Monika, Bhaskar Rajveer. Lyophilization: process, methods and application. European Journal of Pharmaceutical and Medical Research. 2020; 7(10), 274-285. Available at: https://www.google.com/url?q=https://pdfs.semanticscholar.org/e397/53845618df842fb0d0f9d5ebfe70da7d1b3b.pdf&sa=D&source=docs&ust=1646995166919596&usg=AOvVaw0S9ehi5mKkJ_w9i1tGrwRN
- Bhatta S, Stevanovic Janezic T, Ratti C. Freeze-Drying of Plant-Based Foods. Foods. 2020; 9(1):87. Available at: https://doi.org/10.3390/foods9010087