ABSTRACT
In this study, to increase the preservation of phenolic bioactive compounds and antioxidant activity in blueberry pulp, heat treatment associated with addition of xanthan gum was used. A commercial mixture of blueberries (Powerblue, Climax and Bluegen cultivars) was added with 0.08% (w/w) citric acid and subjected to heat treatment by direct heating until 90 °C in conventional open pan (OP) and by direct application of steam (AS); both with and without the addition of xanthan pruni (OPX and ASX), followed by pulping. Samples of only frozed fruits were considered as control. The five treatments remained under freezing and were evaluated until 90 days of storage for antioxidant activity, phenols, flavonoids and total monomeric anthocyanins. The results show that, with the exception of phenolics, heat treatment with direct steam application and xanthan addition favored bioactive compounds preservation during storage. These factors influenced positively on the anthocyanins stability during frozen storage for 90 days. The xanthan addition favored antioxidant activity preservation; preservation for antioxidant activity by ABTS and DPPH, in all heat treatments, was observed.
Index terms
Blueberry; Vaccinium ashei; fruit pulp; heat; fruit technology; storage