The effect of transition to a more energy-effective processing regime on the shelf-life of lingonberry-blueberry-rye puree

Environmentally sustainable production is becoming a relevant topic for both consumers and producers. Reducing the energy consumption in the production phase helps to achieve a lower ecological footprint. The aim of this research was to evaluate the effect of switching from resource-intensive heat treatment (108 °C, 27 min) to a more economical pasteurization process (93 °C, 9 min) on the shelf-life and quality of lingonberry-blueberry-rye puree. Room-temperature and accelerated shelf-life test (ASLT) were conducted with lingonberry-blueberry-rye puree samples, processed with different heat treatment regimes. The second aim of the research was to validate an ASLT model for the product. During both shelf-life tests, anthocyanins and total phenolic content (TPC) were analysed. The initial results showed that samples with higher temperature treatment contained lower amounts of anthocyanins and TPC. The content of anthocyanins in both shelf-life tests decreased immediately after first analysed point (on average 74.5%) and by the end of the test, it was equal for samples from both heat treatment regimes. These changes were also confirmed with colorimetric analysis, showing a rapid change in colour after first analysed point. Sensory analysis showed minimal differences between samples from both heat treatment regimes and minimal changes were found throughout both storage tests. Therefore, the use of pasteurization process can be recommended. ASLT was carried out on the assumption that the aging factor is Q10=3. An exact Q10 value was calculated for this product, based on the reaction rates of the main quality changes observed during both storage tests. It was found that an ASLT with lingonberry-blueberry-rye puree or similar products should be carried out with Q10=2.7.