PHENOLIC COMPOUNDS IN CHAYA (Cnidoscolus aconitifolius) LEAVES, JERUSALEM ARTICHOKE (Helianthus tuberosus L.) RHIZOMES, AND AMARANTH (Amaranthus cruentus) SEEDS: A COMPARATIVE EVALUATION

Chaya (Cnidoscolus aconitifolius), Jerusalem artichoke (Helianthus tuberosus L.), and amaranth (Amaranthus cruentus) are plant species of nutritional and functional interest due to the presence of bioactive compounds. Chaya stands out for its high phenolic compound content and antioxidant activity, while Jerusalem artichoke rhizomes are primarily recognized for their high inulin content, in addition to containing phenolic compounds that contribute to their functional potential. Amaranth seeds, in turn, stand out for their nutritional value, particularly their protein content, while also containing phenolic compounds. The determination of these compounds is important for characterizing the bioactive potential of these raw materials and expanding their potential applications in the food industry. Therefore, this study aimed to evaluate the phenolic compound content of these plant species. Chaya flour (CF), Jerusalem artichoke rhizome flour (JARF), and amaranth seeds (AS) were collected in the municipality of São Lourenço do Sul, Rio Grande do Sul, Brazil, and transported to the Food Technology Laboratory (LTA) at the Federal University of Rio Grande (FURG). The moisture content of the samples was determined according to the official AOAC method. Phenolic compound content was determined by methanolic extraction, followed by quantification using the Folin–Ciocalteu method, with absorbance measured at 750 nm. The data were subjected to analysis of variance (ANOVA), followed by Tukey’s test (p < 0.05), and the results were expressed as mean ± standard deviation in mg GAE/g. The moisture contents of CF, JARF, and AS were 5.53 ± 0.20%, 5.75 ± 0.10%, and 15.31 ± 0.88%, respectively. CF showed a mean total phenolic compound content of 52.071 ± 4.421 mg GAE/g, whereas JARF and AS showed values of 0.316 ± 0.127 mg GAE/g and 0.170 ± 0.037 mg GAE/g, respectively, with a significant difference observed between CF and the other samples. The higher phenolic compound content observed in CF may be related to the physiological characteristics of leaves, which are important sites for the synthesis and accumulation of secondary metabolites, including phenolic compounds involved in plant protection against biotic and abiotic stresses. In contrast, JARF is characterized by a higher concentration of storage carbohydrates, particularly inulin, whereas AS has a composition predominantly characterized by proteins and lipids, with phenolic compounds occurring at lower concentrations in both samples. Thus, the differences observed among the samples mainly reflect the intrinsic chemical composition of each plant species. It can be concluded that CF has high potential as a source of phenolic compounds, highlighting its potential application as a functional ingredient and in the development of value-added food products.