Critical Evaluation of Changes in the Ratio of Insoluble Bound to Soluble Phenolics on Antioxidant Activity of Lentils during Germination

Abstract

A new indicator, the ratio of insoluble bound phenolics (IBPs) to soluble phenolics (SPs), is suggested as an effective means to monitor changes in the antioxidant activity of lentils during germination. This indicator may be used to monitor other process-induced changes in antioxidant potential of food phenolics in other foods. The antioxidant activity of SPs, IBPs, and total value, the sum of both free and esterified phenolics, of germinated CDC Richlea lentil variety was evaluated for 4 days. Total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging ability were employed to record antioxidant activities. An incremental increase in IBPs was found in TPC, TFC, DPPH, and ABTS radical cation scavenging ability, whereas SPs showed a declining trend in TFC, DPPH, and ABTS, except TPC during 4 days of germination. The ratio of IBPs to SPs increased using most methods, and this may be possibly due to the changes of phenolic compound formation from soluble into insoluble bound form during germination process. The ratio can be used as a novel method for monitoring process-induced changes in the antioxidant activity of foods.

Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects – A review

“…are mainly present in foods in the form of glucosides; p-hydroxybenzoic, vanillic and protocatechuic acids are the most common forms (Herrmann, 1989;Mattila & Hellström, 2007;Shahidi, McDonald, Chandrasekara, & Zhong, 2008;Yeo & Shahidi, 2015). Phenolic acids behave as antioxidants, due to the reactivity of their phenol moiety (hydroxyl substituent on the aromatic ring).…”

“…Lentils have the highest phenolic, flavonoid and condensed tannin contents (7.53 mg gallic acid equivalents/g, 2.21 and 8.70 mg catechin equivalents/g, respectively), followed by black beans and red kidney beans (Xu & Chang, 2007). Pulses with the highest total phenolic content (lentil, black, and red kidney beans) exert the highest antioxidant capacity as assessed by DPPH radical scavenging, FRAP, and ORAC (Xu & Chang, 2007;Yeo & Shahidi, 2015). Condensed tannins (proanthocyanidins) have been quantified in hulls of several varieties of field beans (Vicia faba) Beninger & Hosfield, 2003;Campos-Vega et al, 2010;Smulikowska et al, 2001;Troszyń ska, Estrella, López-Amóres, & Hernández, 2002).…”

Simultaneous release of peptides and phenolics with antioxidant, ACE-inhibitory and anti-inflammatory activities from pinto bean (Phaseolus vulgaris L. var. pinto) proteins by subtilisins

“…Legumes are also rich in phenolic compounds ranging from 1.1 to 68 mg/g of dry weight (Vaz Patto et al, 2015). Phenolic acids and flavonoids are the most abundant phenolics in legumes and they generally occur as free and bound forms, the latter representing up to 50% of the total phenolic content (Gutiérrez-Uribe, Romo-Lopez, & Serna-Saldívar, 2011;Yeo & Shahidi, 2015). Scientific data evidence the potential of polyphenols to improve cardiovascular health through an array of actions including antioxidant, anti-inflammatory, antihypertensive and antiatherosclerotic activities (Del Rio et al, 2013).…”

Bioaccessibility and antioxidant activities of finger millet food phenolics

“…The changes in phenolic content of cereals depend on the type of grain, the preparation method or the cooking procedure employed (Shahidi and Chandrasekara, 2014). Further process induced phenolic content and antioxidant potential changes in soluble and bound phenolic contents have been reported for lentils (Yeo and Shahidi, 2015). The present findings evidence that variety of millet, time of hydrothermal treatment applied and nature of matrix may affect the TPC of finger millet based foods.…”