Major and Minor Anthocyanins and Anthocyanidins Recovered during Juice Processing Steps in Rabbiteye Blueberries by LC MS-MS and UPLC-UV

Blueberry-rich diets deliver anti-inflammatory, anti-carcinogenic, and anti-mutagenic components that help protect the brain, cardiovascular and central nervous system, and apparently reduce cancer, obesity and type 2 diabetes.  Heightened consumer awareness of the health benefits of consuming phytonutrient-rich fruits and aggressive marketing have resulted in expanding markets for blueberries, and their associated products.  Over the last decade (2002–12), the southeastern United States (Alabama, Arkansas, Florida, Georgia, Mississippi, and North Carolina) blueberry production and utilization has increased 3.4-fold while the national value of the utilized blueberry crop increased over four-fold from $194.6 million to $781.8 million.  One of the major classes of phytochemicals in blueberries are the phenols; specifically the anthocyanins.  Blueberry juice processing has multiple steps with each one affecting the chemical composition of the berries.  Anthocyanin decreases have been reported in thermally processed commercial juices. We therefore set out to improve juice quality by using HTST pasteurization in a not-from-concentrate (NFC) regime.  The NFC blueberry juice was made from heating and enzyme treating berries before pressing, followed by ultrafiltration and pasteurization.  Using LC-MS-MS, major and minor anthocyanins were identified and semi-quantified.  Ten anthocyanins were identified, including five arabinoside and five pyrannoside anthocyanins.  Three minor anthocyanins not reported before in rabbiteye blueberries were identified.  These were delphinidin-3-(p-coumaroyl-glucoside), cyanidin-3-(p-coumaroyl-glucoside), and petunidin-3-(p-coumaroyl-glucoside).  These compounds did not significantly change with ultrafiltration and slightly decreased with HTST pasteurization.  The five known anthocyanidins (cyanidin, delphinidin, malvidin, peonidin, and petunidin) were quantified with standards using UPLC-UV.  Raw berries and press cake contained the highest total anthocyanidin contents with 0.519 mg/mL and 2.656 mg/mL respectively.  There was a 46% to 60% loss in total anthocyanidins from fresh fruit to non-clarified and clarified (ultrafiltered) juices, respectively.  Yet, increases of 17% in anthocyanins and 26% in anthocyanidins were seen in ultra-filtrated juice (versus unfiltered) due to membrane concentration during filtration.  Pasteurization of NFC juices resulted in only roughly 4.7% to 5.3% anthocyanidin loss.