Throughout the last decades, many R&D attempts have been made to develop a novel food treatment to allow fruit and vegetable cells to survive after thawing. Among the more promising approaches was vacuum impregnation with proteins and sugars. Over 100 research articles have been published on the topic over the last 15 years. However, the success of the proposed methods were limited due to problems with large ice crystal growth and recrystallization, mainly caused temperature fluctuations during storage.
A research team at the Food Technology Department of the Lund University discovered that fruit and vegetables that are normally unable to bear freezing, could indeed be frozen without the loss of internal cell properties if they are impregnated with naturally occurring cryoprotectants (natural sugars and plant proteins that can naturally bear frost and remain green – for example winter wheat or cassava roots) through the combination of Pulsed Electric Field (PEF) and Vacuum Impregnation (VI). This discovery led to the patent application in 2008.
Subsequently, OptiFreeze was founded in 2011 by Arc Aroma Pure AB (publ), Lund University (LU) Innovation and several researchers at the Department of Food Technology at Lund University. Since June 2014 OptiFreeze is listed at the Swedish Small Cap Spotlight Stock Market (for more information see Investor Relations) and has approximately 2.000 shareholders.
OptiFreeze owns a patented technology that enhances taste, shape and texture of fruit and vegetables throughout the freezing and defrosting (thawing) process. OptiFreeze has furthermore developed a method that can improve shelf life of fresh cut fruit and vegetables. Also the shelf life of flower cuttings can be significantly improved. The same technology can be used to dry herbs to reduce drying time while enhancing taste, smell and colour. The technology provides new business opportunities for food processors and distributors all around the world. The cryoprotectants used in the process to protect the cells, which enhance the taste, shape, texture and shelf life.
The technology is based on the same principle which allows certain plants, for instance winter wheat, to bear frost and remain green, even after cold winter days. Natural sugars and anti-freeze proteins are extracted via natural or enzymatic methods from plants such as winter wheat and cassava roots. These compounds are infused into fruits, vegetables, berries and herb cells, and by doing so the frost protection property is transferred.
The fruit, vegetable, berry or herb will bear the cold in the same way as the grass or winter wheat. The method for cell protection is based on the novel combination of Vacuum Impregnation (VI) and Pulsed Electric Field (PEF).
Vacuum impregnation works as follows: first, air is evacuated from the product's extracellular space by lowering the pressure. The product is immersed in a solution containing natural cryoprotectants during the treatment while the pressure is at the lowest level inside the treatment chamber. Lastly, the pressure will increase to atmospheric pressure and the solution then enters the extracellular space in the product.
After vacuum impregnation, the product is exposed to very short high-voltage electrical pulses, which create pores in the cell membranes allowing the sugar to enter on an intracellular level. As soon as the electrical field is withdrawn, the cell membranes reseal themselves.