UUDISED

GOOD PROJECT EXAMPLE: Valorization of the Apple Juice Pressing Residue and Fermented Apple Juice Products by Converting the Residues into Apple Puree and Additional Products from Apple Puree

The problem to be solved

The use of pressing residue generated in apple juice production is an issue throughout the world. The world production of apples in 2019 was over 86 million tons, with approximately a quarter produced in Europe. According to estimation, more than half of the produce is marketed fresh. The main product made from apples is juice, which generates a considerable amount of residue – about 25-50% depending on the pressing conditions. In terms of quantities, it means that every year millions of tons of pressed residue is generated, of which only 20% is recovered (composting, low-quality feed, production of pectin). Thus, approximately 80% of the residue remain unused and is incinerated or used as landfill.

In terms of sustainable circular economy, it would be rational to explore what technologies can be used and to what extent the residue from the pressing of apple juice can be used for producing raw materials suitable for human consumption and what kind of products can be made from such raw material. 

Project outcomes

The main objectives of the project were to investigate the possibilities for the valorisation of the residues generated in the production of apple juice and fermented apple juice into apple puree and novel products made from that puree. It turned out that the sieving method can be used for producing apple puree from the pressed residue of apple juice. The chemical, rheological and sensory characteristics of the apple puree demonstrates that it can be used as the basic raw material for various products. The sensory characteristics of the apple puree produced from various pressing residues (various varieties, pressing stage, season, enzymatic processing) demonstrated that the final product depends mostly on the used additional compounds. Whereas without additional compounds, the smell and taste of the puree were rather neutral.

To produce large volumes of apple puree from the residues of producing apple juice, it is necessary to add an extra amount of water. The optimum amount of water used in half-automated devices was identified. However, the amount of water may vary between devices depending on the technological parameters of the sieving device. Thanks to the construction of the new production plant, Siidrikoda Ltd. has the capability to use the technology and knowledge gained in this project. The extent of the company’s circularity should increase significantly thanks to the production of new products. 

“The residue of apple juice is in every way suitable for human consumption and using it as landfill is an obvious waste of resources.” Rain Kuldjärv