Determination of Total Phenolic Content in Almonds After Lipid Removal or After Deproteinization

Abstract

The classical method for polyphenols extraction requires long time and large amounts of reagents used. Our objective was to compare the results obtained using this method with results obtained using a direct method. The research was made on almonds cultivated in Palma de Mallorca, Spain. The polyphenol content of almond kernels were examined in two different ways: polyphenols extraction after lipid removal or after sample deproteinization. Commune and selected kernels were provided from Spain. One gram of almonds with 10 mL water were homogenized. In the first case,10 mL were colected and extracted two times with hexane to remove lipids,first extraction all night long, and second extraction, 4-5 h. Polyphenols were extracted from aqueous phase with HCl:H2O:methanol during 16 h at 4 °Ϲ. The methanolic extract was retained and evaporated under nitrogen and the residue was reconstituted in 10 mM phosphate buffer. In the second case, the homogenate was deproteinized with acetone. Total phenols were assayed colorimetrically with the Folin-Ciocalteu. The calibration curve was made using pyrogallol. The results showed an effect for obtaining method, but not for almond varieties. Using extraction to remove lipids may cause losses in total polyphenols content while deproteinization avoides these polyphenol losses and reduces time and reagents.