Phenolic profile of whole seeds and seed fractions of lentils and its impact on antioxidant activity

Seed color and size are the major traits influencing consumer's acceptability and market class of lentils worldwide.In this paper we assessed the in vitro antioxidant capacity of whole seeds, hulls, and cotyledons of fivelentil varieties in relation to their phenolic profile. The samples were evaluated for total polyphenol content anddifferent phenolic classes, such as condensed tannin content, total monomeric anthocyanins, and phenolic acids.Individual phenolic compounds, including flavonols, flavanols, flavones, anthocyanins, and phenolic acids, werefurther quantitatively investigated by HPLC-DAD. Total antioxidant capacity was evaluated by ABTS and ORACassays, and a direct measurement (ABTSdir) was used to evaluate the antioxidant capacity of the bioactivecompounds present in the whole-meal flours without extraction. The five genotypes showed considerable variationsin their phenolic content and profile as well as antioxidant activities. The results showed a preferentialaccumulation of phenolic compounds with antioxidant activity in the hulls compared to cotyledons. Delphinidinand cyanidin were the most abundant flavonoids in the hulls, while epicatechin and catechin were the mostconcentrated in the cotyledons. A highly significant correlation was observed between ABTS, ORAC and ABTSdirand total polyphenols. The antioxidant capacities were highly correlated with several individual phenolicsdetected in hulls and cotyledons. The overall results showed that the lentil fractions and extracts with higherphenolics had also higher antiradical activity which was independent on seed size and color. Identifying lentilgenotypes with diverse phenolic profile in cotyledons and whole seeds could meet diverse consumers preferencesand health requirements.