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Enrichment in phenolic compounds of black ripe olives through nano-filtration and vacuum evaporation techniques

García-Serrano, Pedro, Romero, Concepción, Brenes, Manuel, García-García, Pedro
Innovative food science & emerging technologies 2019 v.51 pp. 73-79
bioactive compounds, color, evaporation, flavor, human health, nanofiltration, olives, packaging, phenols, texture, washing
The aim of this work was to obtain ripe olives enriched in bioactive compounds of phenolic nature. For this, two partially purified solutions rich in phenols from the table olive processes were used as cover in the packaging: washing waters of Spanish-style green olives or previous preservation acid solutions of ripe olives. Both solutions were nano-filtered through a 4000 Da membrane and vacuum evaporated at pilot plant scale. Regenerated liquids were employed at 50% and 100% in the packing brine. Results demonstrated that it is possible to achieve a >3-fold higher concentration of phenolic compounds in olives than with the traditional method when using the regenerated washing water at 100% to enrich the packing brine. Moreover, a <2-fold higher concentration was found in olives enriched with the regenerated preservation solution at 100%. It must also be noted that the color, texture and flavor of the olives were not affected by the use of regenerated washing water as packing solution.Among the different types of commercial table olives, black ripe have the lowest content in phenolic compounds. The methodology developed in this work will allow the enrichment of black olives in these bioactive substances, in particular hydroxytyrosol, which has been attributed to many beneficial properties for human health. The methodology is simple and easy to implement by processors. Hence, these results will contribute to the nutritional valorization of black ripe olives.