Lingonberry press-cake for food shelf-life extension

Lingonberry is a common wild berry in the Northern hemisphere. Due to its natural content of benzoic acid, prepared jams and drinks are stable without needing additional preservatives. When producing drinks there are substantial remains in the form of a press-cake, which also contains benzoic acid. In this project, we explored the possibility to use the press-cake to partly substitute the main ingredients in food products, using falafels and sausages as vegan and meat-based examples. The main objective was to determine if the shelf life could be extended but there were also some focuses on the possibility to produce products attractive for potential consumers. As the final concentrations of benzoic acid would be rather low, the products were vacuum-sealed and stored at refrigerated concentrations. Microbials contents were quantified during storage, both the propagation of inherent microbial flora, and added microorganisms in the form of challenge test. A notable observation was due to the storage conditions; microbial stability was acceptable for all products including the reference products. However, in the sausages, which were not subjected to thermal treatment during manufacturing, in the reference and with 5% press-cake, the total bacterial count increased from log 2 to log10, whereas, with 10% press-cake, only an increase to log 4 was observed. Based on sensory analyses, it is not feasible to increase the amount of press-cake to make the products more stable. Hence, despite other potential benefits of using lingonberry press-cake as an ingredient, it cannot be used to improve food safety. • The possibility to use lingonberry press-cake as a food ingredient was explored • Limited microbial growth in vacuum-sealed food products stored in the fridge • Benzoic acid negatively affects bacterial growth at subinhibitory levels