Analysis of a whole diet in terms of phenolic content and antioxidant capacity: effects of a simulated gastrointestinal digestion

Abstract

This work compares the phenolic contents and the total antioxidant capacity of the 36 most popular Brazilian foods submitted to aqueous extraction or in vitro digestion. The purpose was to evaluate the extent by which digestion differs from the simple aqueous extraction procedures of several food matrices. After in vitro digestion, cereals, legumes, vegetables, tuberous vegetables, chocolates and fruits showed higher phenolic contents and higher antioxidant activities than those obtained by aqueous extraction. Contrarily, the digestion caused a reduction in the phenolic contents and antioxidant activities of beverages (red wine, coffee and yerba mate). Our results suggest that the phenolics of food groups with solid and complex matrix are protected against enzymatic action and alteration in pH during the digestion, what does not occur in liquid food matrices such as the beverages. This fact would overestimate the antioxidant activities of beverages submitted solely to aqueous extraction.

Keywords:

• Flavonoids
• food analysis
• in vitro digestion
• phenolics
• total antioxidant capacity

Acknowledgments

This work was supported by grant of Fundação Araucária (Paraná, Brazil). R.M.P. and A.B are Research Fellows of Conselho Nacional de Pesquisa e Desenvolvimento (CNPq).

Disclosure statement

The authors declare no conflicts of interest.