Content and antioxidant capacity of phenolic compounds in quinoa seed: A review

Quinoa (Chenopodium quinoa Willd.) is an ancestral pseudocereal native to the Andean region of South America. Due to its wide genotypic diversity, it has been described as a species capable of adapting to different agroclimatic environments, which influence the composition of the seed. Quinoa is known for its high protein and essential amino acid content. It is also rich in vitamins, minerals, and phenolic compounds. This review summarizes the scientific information on the content of phenolic compounds and the in vitro antioxidant capacity of quinoa seeds determined by spectrophotometric methods. Discrepancies in the available data, resulting from the use of different experimental variables, have also been addressed. The data analysis identified a clear need for standardized methodology to produce comparable results. Regarding antioxidant potential, in vitro studies provided basic information, which is complemented by in vivo bioavailability studies. According to the information collected, future research is required to evaluate the effect of environmental stress, geographic aspects, and quinoa growing conditions on the antioxidant potential of the seed.