Antioxidant activity and phenolic content of flour and protein concentrate of amaranthus cruentus seeds

The aim of this work was to investigate bioactive compounds and antioxidant activity in flour (FAc) and protein concentrate (PCAc) from Amaranthus cruentus seeds (Ac), and to study their effect on the liver histoarchitecture of Wistar rats. Total phenols (mg gallic acid eq/100 g dry weight) content was 73.78 ± 1.70 for FAc, and 190.23 ± 1.50 for PCAc. The antioxidant activity was estimated by: 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide scavenging activity (NO) and β-carotene bleaching method (β-carotene). The values expressed as percentage correspond to FAc and PCAc, respectively. DPPH: 86.30 ± 1.1 and 88.83 ± 1.2; NO: 29.38 ± 1.9 and 48.75 ± 1.7; andβ-carotene: 83.00 ± 1.8 and 44.60 ± 1.5. The histopathological diagnosis indicates that casein-fed rats present moderate fat infiltration in the liver, whereas in PCAc-fed rats, the liver has structural integrity. The presence of phenols would provoke an increase of the antioxidant defenses and would produce a protective role in liver. It is suggested that Ac could be a good antioxidant source. PRACTICAL APPLICATIONS: A number of epidemiological studies initially indicated the utility of antioxidants in disease prevention, particularly for cardiovascular disease and cancer. This association is often attributed to different antioxidant components, such as polyphenols, vitamin C, vitamin E, carotenoids and other phytochemicals. Amaranth species are receiving special attention in developing countries as an alternative to tackle protein deficiencies in diets. At present, some studies have been conducted on amaranth antioxidant activity (AA). Furthermore, protein concentrates, as nutritional sources, also exhibit physiological effects. In order to understand the protective effect of natural compounds, in vitro studies of antioxidant components must be conducted, followed by an assessment of their antioxidant function. Our results are a contribution to research into new sources of natural antioxidants in this and other related species, and we hope that they will enhance the national food composition database.