This study aimed to provide an updated critical review of the nutritional, therapeutic, biotechnological, and environmental aspects involved in the exploitation of Chenopodium quinoa Willd and its biowastes. Special attention was devoted to investigations of the therapeutic and nutritional properties of different parts and varieties of quinoa as well as of the use of the biowaste resulting from the processing of grain. Studies published from 2018 onward were prioritized. Extracts and fractions obtained from several Chenopodium quinoa matrices showed antioxidant, antidiabetic, immunoregulatory, neuroprotective, and antimicrobial effects in in vitro and in vivo models and some clinical studies. The activities were attributed to the presence of phytochemicals such as polyphenols, saponins, peptides, polysaccharides, and dietary fibers. Quinoa wastes are abundant and low-cost sources of bioactive molecules for the development of new drugs, natural antioxidants, preservatives, dyes, emulsifiers, and carriers for food and cosmetics applications. Among the demands to be fulfilled in the coming years are the following: (1) isolation of new bioactive phytochemicals from quinoa varieties that are still underexploited; (2) optimization of green approaches to the sustainable recovery of compounds of industrial interest from quinoa by-products; and (3) well-conducted clinical trials to attest safety and efficacy of extracts and compounds.
Keywords: agro-industrial wastes; bioactive compounds; quinoa; sustainability; upcycling.