Profiling the impact of thermal processing on black raspberry phytochemicals using untargeted metabolomics

Abstract

Clinical and laboratory studies have implicated black raspberries (BRBs) and their associated phytochemicals in the modulation of several chronic diseases. Most research on the health benefits of BRBs is conducted using freeze-dried or otherwise minimally processed products, yet BRBs are typically consumed as thermally processed goods like jams and syrups. The objective of this work was to profile the chemical changes that result from thermal processing of BRB powder into a nectar beverage. Using an untargeted UHPLC-QTOF-MS metabolomics approach, key degradation products of anthocyanins were identified along with several other proposed phenolic degradants. The effects of processing on other key BRB compound groups, including ellagitannins, are also discussed. This work demonstrates the utility of an untargeted metabolomics approach in describing the chemistry of complex food systems and provides a foundation for future research on the impact of processing on BRB product bioactivity.

Authentication of “Adelita” Raspberry Cultivar Based on Physical Properties, Antioxidant Activity and Volatile Profile

“…These results could be explained by the effect of the temperature applied during the HS-SPME, which modified the raspberry cell walls, mainly due to pectin and hemicellulose depolymerisation that enhanced the extractability of the studied compounds [ 23 ]. Increasing the extraction temperature has been reported to be a good way of improving the extraction recovery, but high temperatures are also associated with the unwanted generation of artefacts such as BB interactions, which have been shown to have negative effects [ 5 ].…”

Dose‐Dependent Increases in Ellagitannin Metabolites as Biomarkers of Intake in Humans Consuming Standardized Black Raspberry Food Products Designed for Clinical Trials

“…[ 39,49 ] ET stability in the confections and nectar was consistent across an 8‐week period. [ 39,50 ] During this time period, the high‐dose confection and nectar groups consistently delivered 50 and 46 mg of ETs while the low‐dose confection and nectar groups delivered 25 and 17 mg of ETs, respectively. [ 39 ]…”

“…The BRB, for example, when evaluated by a non‐targeted metabolomic analysis showed over 4000 different UPLC peaks. [ 50 ] We chose to study BRBs based upon the anti‐cancer bioactivity of relevant phytochemicals in vitro [ 12–14,17,41,54,55 ] and accumulating studies of cancer preventive activity in rodent models. [ 16,19,40,47,56,57 ] Notably, due to the modest exposure of most populations to BRBs and the lack of specificity of berry intake on food frequency questionnaires, it is unlikely that epidemiological studies will provide insightful data regarding BRBs and cancer risk or other health outcomes.…”

Widely Targeted UHPLC-MS/MS Metabolomic Analysis on the Chemical Variation in Blueberry-Filled Pastries During Processing

“…For example, protocatechuic acid in the blueberry filling increased by four times after stir-frying. Protocatechuic acid was reported to be thermally degraded from cyanidin by the liberation of the catecholic B-ring or from flavonoids such as quercetin (9). It shared the same ortho-dihydroxyphenyl chemical moiety with cyanidin, which was reported to be critical for the biological properties of anthocyanins (22,23).…”

“…The application of metabolomic study on the tracking of dynamic compositional changes during food processing could provide a holistic view on the chemical changes and correlated reactions under various treatments of food. Thus, in recent years, metabolomic analysis has been applied in food products, such as in the investigation of nectar beverage of black raspberries (9), roasted coffee beans (10), wines (11), and extra-virgin olive oil (12).…”