Assessment of black ripe olive processing for acrylamide mitigation

Abstract

Black ripe olives contain significant levels of acrylamide. In this study, several mitigation strategies were assessed. The preservation time of olives before the darkening stage was evaluated in 18 batches of fruits of the Hojiblanca, Manzanilla, and Cacereña cultivars, and there was no observed influence on acrylamide formation due to the length of this period. Moreover, great variability was found among batches, with the level of acrylamide being lower in olives of the Cacereña cultivar (ca. 175 μg/kg) than in Hojiblanca (ca. 360 μg/kg) and Manzanilla (480 μg/kg). A reduction (13–20 %) of the acrylamide content was achieved by substituting the preservation brine/tap water mixture with only tap water during darkening. Also, extending the washing stage of pitted olives by up to 20 h instead of 0.5 h gave rise to a 17% reduction in the acrylamide content. The sterilization step was studied at 119, 121, 123, and 125 °C, and it was ruled out that a high temperature and short time process could contribute to a decrease in the level of acrylamide in olives. Surprisingly, the content of this compound in black ripe olives increased linearly up to 20 sterility units (F0), remaining almost constant at higher sterilization intensity.