Anais do Simpósio Latino Americano de Ciências de Alimentos
Anais do 14 SLACA - Simpósio Latino Americano de Ciência de Alimentos

Blackberries present in their composition bioactive compounds, such as anthocyanins. Most of these compounds remain in the pomace during juice extraction, as observed for the pressing method. Therefore, an ultrasound pretreatment was used to improve the amount of anthocyanins in blackberry juice. Erlenmeyers containing 60 g of blackberry were placed in the ultrasonic bath (25 kHz and 100 W) without adding solvents. Juices were obtained by pressing the blackberries with a manual juicer. Optimization of the ultrasonic pretreatment was performed by central composite rotational design using blackberries of an unknown cultivar. Ultrasound amplitude and time were evaluated as independent variables (total of 12 experiments), with total monomeric anthocyanin content as the response. The optimal pretreatment conditions were found using response surface methodology. After defining the ideal ultrasound parameters, blackberries of the cultivars BRS Xingu, Guarani, and Xavante were used to verify the difference between the anthocyanin content removed from the blackberries with and without ultrasound pretreatment. Anthocyanins were quantified and identified by LC-DAD-MS/MS. The optimal pretreatment conditions were 65% of amplitude of US for 7 minutes. In all cultivars five anthocyanins (cyanidin-3-glucoside, cyanidin-3-rutinoside, pelargonidin-3-glucoside, cyanidin-3-malonyl-glucoside, and cyanidin-3-dioxalylglucoside) were identified. The same compounds were identified in the ultrasound-treated juices as in the controls. Cyanidin-3-glucoside was the majority anthocyanin. Ultrasonic pretreatment increased the extracted anthocyanin content by 56%, 30%, 54% for BRS Xingu, Guarani, and Xavante, respectively. This improvement can be related to the cavitation effect, which led to the disruption of the greater number of plant cells and increased the release and dissolution of anthocyanins in the in situ water of fruits. Therefore, ultrasonic pretreatment increased the anthocyanins in blackberry juices in a fast and sustainable way.