Berries are currently being researched for their potential to prevent certain diseases, including oral cancer. Fresh berries are more commonly studied, although processed berry products are commonly consumed. The objective of this work is to understand how storage temperature influences the phytochemical profile and bioactive properties of a processed black raspberry nectar. Nectar was UHT sterilized and aseptically packed prior to storage at -20, 4, 10, 25, and 35 °C. Samples were removed from storage at 10 d intervals. Untargeted chemical profiles of nectar extracts were acquired using UHPLC-QTOF-MS operated in ESI(-). Identical extracts were applied to SCC-83 precancerous oral epithelial cells to assess growth inhibition as a measurement of bioactivity. Among storage conditions, only storage at 35 °C resulted in a decrease of approximately 13% in growth inhibition activity between 10, 20, and 60 d. This was despite variation in the untargeted chemical profiles of all samples that increased with storage temperature. A targeted extraction of the chemical data showed opposing time and temperature-dependent changes in levels of cyanidin-3-O-glucoside (C3G) and protocatechuic acid (PCA). When tested alone, these compounds exhibited dose-dependent inhibition of cell growth, but when total concentration was constant while altering ratios of C3G:PCA, inhibition was maintained at a constant level. Together these observations suggest that the chemical changes incurred through storage can contribute to bioactivity, and monitoring only single compounds ignore the complexity of bioactive components in foods. This study will inform best practices for production and storage strategies of berry-based functional foods. It also demonstrated that isolated phytochemicals do not explain the complete bioactivity of a complex food product.

Storage conditions affect the untargeted chemical profile and bioactivity of black raspberry nectar intended for use in clinical trials

255th National Meeting (2018)

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