The high ascorbic acid content is the main cause of the low stability of anthocyanin extracts from acerola

Abstract

Acerola is considered to be one of the best natural sources of ascorbic acid (AA) and, for this reason, the influence of this component on the stability of anthocyanins from acerola extracts was determined and compared to those from açai, which have no detectable AA. The addition of three different levels of AA to the solution of açai anthocyanins resulted in a 110-fold increase in the degradation rate ( k obs) at the highest fortification level (276 mg/ml). The fact that the flavonoid concentration of the açai anthocyanin extract was 10 times higher than that of the acerola was probably responsible for the three times higher stability of the AA-fortified açai system compared to the acerola system, both at the same AA concentration and similar total polyphenol levels. The higher the level of AA addition to açai anthocyanin solutions, the greater was the colour fading, indicated by increase of L ∗ and decrease of a ∗ and C ∗ values.