Antioxidant activity of hydrolysates and peptide fractions of glutelin from cocoa (Theobroma cacao L.) seed

Erik G Tovar-Pérez,Lucia Guerrero-Becerra,Eugenia Lugo-Cervantes

doi:10.1080/19476337.2017.1297963

Abstract

ABSTRACTGlutelin fraction from cocoa almond was hydrolyzed with alcalase for the production of hydrolysates. These were then fractionated by ultrafiltration to obtain peptides with a molecular weight (MW) lower than 3000 Da. The antioxidant activity (AOX) of the hydrolysates and peptides was assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+), and oxygen radical absorbance capacity (ORAC) assays. Ultrafiltered peptide fraction with the highest AOX was purified by size exclusion chromatography, by which four main peaks were identified with a MW between 535 and 2959 Da. The peptide fraction P1 (MW = 2959 Da) showed the highest capacity to scavenge DPPH• and ABTS•+ radicals with radical scavenging activity DPPH• and ABTS•+ with EC50 values of 237.48 and 19.29 µg/mL, respectively, which were similar to those obtained with glutathione. These results show that enzymatic treatment of cocoa glutelin comprises an attractive bioprocess for the production of peptide fractions with AOX, which could be included in the design of functional foods; moreover, they show an alternative use of cocoa.

Highlights

Free radicals, antioxidants, and oxidative stress are common terms when exploring the mechanisms involved in the origin of a vast number of diseases
Free radicals are continuously produced in the human organism by means of biochemical reactions, which occur as part of the cell metabolism and which are associated with the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS); both of them are responsible for oxidative damage to macromolecules, such as DNA, lipids, carbohydrates, and proteins (Valko et al, 2007)
There is an antioxidant defense system limiting the noxious effects of these radicals; this system can remove reactive species through the use of enzymatic (superoxide dismutase, glutathione (GSH) peroxidase, and catalase) and non-enzymatic antioxidants (Cai et al, 2015)

Summary

Introduction

Antioxidants, and oxidative stress are common terms when exploring the mechanisms involved in the origin of a vast number of diseases (chronic degenerative, neurodegenerative, and some types of cancer). Within this context, free radicals are continuously produced in the human organism by means of biochemical reactions, which occur as part of the cell metabolism and which are associated with the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS); both of them are responsible for oxidative damage to macromolecules, such as DNA, lipids, carbohydrates, and proteins (Valko et al, 2007). The second most abundant component in the cocoa seed is protein (10–15%), which is constituted by four fractions: albumin (ALB), globulin (GLO), prolamin (PRO), and

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