EFFECTS OF DIFFERENT PHENOLS EXTRACTION CONDITIONS ON ANTIOXIDANT ACTIVITY OF ALMOND (PRUNUS DULCIS) FRUITS

ABSTRACT In order to determine the optimum operational conditions for phenols extraction, a series of assays were performed in the Guara variety of almond (Prunus dulcis). Four variable operational conditions factors were considered: solvent type, solvent volume, temperature and extraction time. Phenols extracts antioxidant properties were evaluated, either chemically, by screening the free radical scavenging activity, or biochemically, by measuring the inhibition of thiobarbituric acid reactive substances formation in brain cells used as model for the study of lipid peroxidation damage in biomembranes. The extraction of the totality of phenols, confirmed by their antioxidant properties, allows the calculation of ideal doses for almond intake concerning antioxidant effects. The best outcome, regarding these proposals was obtained in the following conditions: 50 mL of methanol with 60 min of extraction time at 25C. PRACTICAL APPLICATIONS The quantification of total phenols in the extracts allows the definition of the most adequate doses of almond to be included in healthy diets in order to obtain the best antioxidant effects. This is quite important as it is not yet well defined if the over-intake of these compounds can cause deleterious effects. The correlations obtained between phenols and antioxidant activity allows an estimation of extract concentration providing 50% inhibition values instead of their experimental determination. In future works with the same or other varieties we can achieve antioxidant activity parameters through phenols determination. From an industrial point of view, the obtained results offer a possibility to valorise almond as a better food product obtained from an economical natural resource. Furthermore, almond tree could be cultivated more intensively, namely in areas with little agricultural potential, as it represents a culture with modest needs in terms of practical management.