Tastier and healthier strawberries using innovative freeze-drying method

"Ongoing development of innovative strawberry freeze-drying tevchnology, with online control and optimisation of product quality parameters, based on artificial intelligence algorithms and spectral measurements", is a project that the Wrocław University of Environmental and Life Sciences will implement in a consortium with the Łódź University of Technology and the "Klasa" Producers Group. For the development of this new technology, a team led by Professor Adam Figel from the Institute of Agricultural Engineering of the UPWr has received over PLN 1.9 million in support from the National Centre for Research and Development as part of the Fast Track competition.

The goal of the project is to design and build an innovative, continuous freeze dryer for freeze-drying strawberry particles. The freeze-drying process will then be shorter and more convenient, and the level of fruit loss will be much lower. In addition, the strawberries will retain more flavour and aroma and a higher nutritional value than strawberries previously freeze-dried in industrial conditions.

Optimisation of quality parameters and lower energy consumption

– Heat is to be supplied to the frozen material in a hybrid manner – using various energy sources. This approach is expected to shorten the freeze-drying time, and thus reduce the energy consumption of the process. In addition, the operation of the dryer will be controlled by a computer programme using artificial intelligence algorithms and fuzzy logic integrated with a data collection and machine learning system. This will allow for optimising the product quality parameters and minimize energy consumption – explains project manager Professor Adam Figiel, emphasising that the UPWr is mainly responsible for research on the quality of products and the correct process of drying fruit.

This, in turn, will lead to a much improved final product – freeze-dried strawberry particles with a specific shape (e.g. in the form of cubes, slices) and of increased quality compared to the lyophilisates from the classic process. The final freeze-dried products will have a higher content of polyphenols and volatile substances and a better texture due to the reduction of internal collapsing of the structure of the lyophilisate, as well as better sensory values.

The dryer, after rescaling to the production conditions, will be used by the "Klasa" Producers Group fruit and vegetable processing plant, and the strawberries will be used in the food industry in the production of, among others, cereals, muesli, sweets and all kinds of healthy snacks.

This is the second UPWr project implemented together with "Klasa" Producers Group, which concerns freeze-drying of fruit. The aim of the first one (its implementation is ongoing) is to build freeze-dryers for drying strawberries in the form of pulp, and drying vegetables and herbs. In this case, the sublimation process is to be improved thanks to the use of infrared and microwave radiation, and the long-term desorption time is significantly reduced by direct, contact or indirect application of ultrasound to the raw material in a nitrogen atmosphere.

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