No abstract

Extracts of polyphenolic compounds were obtained from seeds of faba bean, broad bean, adzuki bean, red bean, pea, red lentil and green lentil using 80% (v/v) acetone. The total antioxidant activity (TAA) of extracts was determined and their astringency (Sensation Astringency Indices – SAI) investigated using the sensory scaling method. The content of tannins in extracts was expressed as absorbance values at 500 and 550 nm after color developed with vanillin/HCl reagent and after n‐butanol‐HCl hydrolysis, respectively. A statistically significant correlation was found between the TAA values and total phenolics (P = 0.01), TAA and tannins determined by vanillin method (P = 0.05), TAA and tannins determined after n‐butanol‐HCl hydrolysis (P = 0.05), SAI values and tannins determined with vanillin method (P = 0.10), SAI values and tannins determined after n‐butanol‐HCl hydrolysis (P = 0.05), SAI values and total phenolics (P = 0.01), total phenolics and tannin content determined by vanillin method (P = 0.01), total phenolics and tannin content determined after n‐butanol‐HCl hydrolysis (P = 0.05), tannins determined with vanillin method and tannins determined after n‐butanol hydrolysis (P = 0.02).

Phenolic compounds were extracted from defatted almond seeds using 80% aqueous acetone. Crude extract was applied onto a Sephadex LH-20 column. Fraction I consisting of low-molecular-weight phenolics was eluted from the column by ethanol. Fraction II consisting of tannins was obtained using water-acetone (1:1, v/v) as the mobile phases. Phenolic compounds present in the crude extract and its fractions showed antioxidant and antiradical properties as revealed following studies using a b-carotene-linoleate model system, total antioxidant activity (TAA) method, 2,2-diphenyl-1picrylhydrazyl (DPPH) radical scavenging activity and reducing power evaluation. Results of these assays showed highest values when tannins (fraction II) were tested. For example, TAA of tannin fraction was 3.93 mmol Trolox/g, whereas the crude extract and fraction I showed values of only 0.24 and 0.09 mmol Trolox/mg, respectively. The content of total phenolics in fraction II was the highest (80.4 mg/g). The content of tannins in this fraction determined using the vanillin method and expressed as absorbance units at 500 nm per 1 g was 2436. The high-performance liquid chromatography (HPLC) analysis of almond seed crude extract showed the presence of phenolic compounds, Journal of Food Lipids 12 (2005) 344-358. All Rights Reserved. © Copyright 2005, Blackwell Publishing 344 namely vanillic, caffeic, p-coumaric, ferulic acids (after basic hydrolysis), quercetin, kaempferol and isorhamnetin (after acidic hydrolysis), delphinidin and cyanidin (after n-butanol-HCl hydrolysis) and procyanidin B 2 and B 3 . 345 ANTIOXIDANT ACTIVITY OF ALMOND 346 R. AMAROWICZ, A. TROSZYŃ SKA and F. SHAHIDI