Estudo do potencial antioxidante de extratos hidroalcóolicos de Pereskia aculeata (Ora- pro-nobis), Camellia sinensis (chá verde e chá branco) e suas misturas em matriz lipídica.

Abstract

Oxidation processes produce highly reactive chemical species called free radicals that degrade the food fatty acids. Antioxidant compounds found in various plants can slow down this process. In this work the extraction of phenolic compounds from Camellia sinensis (green tea and white tea) and Pereskia aculeata (Ora-pro-Nóbis) plants was performed with mixed solvent of water:ethanol, varying its proportions in 75:25, 50:50 and 25:75 (v/v), with or without the ultrasound method. The green tea extract showed the highest contents of total phenolics and antioxidant activity in the DPPH test, while Ora-pro-nobis showed the lowest results. Ultrasound bath was not effective in increasing the content of bioactive compounds. One extract from each plant was selected for a mixture planning, where they were applied in soybean oil and olive oil under Rancimat accelerated oxidation test. All extracts and their mixtures showed antioxidant activity in both oils, increasing their oxidation induction times. Green tea had a greater positive influence on soybean oil, while white tea had a greater positive influence on olive oil. In the desirability test, it was obtained that the mixture to obtain the highest result in the induction time for soybean oil was 100% green tea extract, and for olive oil the ideal proportion would be 75% white tea and 25% green tea. The presence of ora-pro-nobis in the mixtures resulted in antagonistic effect, however its pure extract showed significant antioxidant potential. Thus, the extracts presented antioxidant potential for possible replacement of synthetic antioxidant in soybean oil and olive oil.