Caracterização química e otimização da extração de compostos bioativos das folhas de Echinodorus grandiflorus com aplicação em iogurte

Abstract

Plants are important sources of phenolic compounds that have antioxidant and antimicrobial activities capable of contributing to the prevention and control of various diseases. Echinodorus grandiflorus is a plant widely used in the treatment of diseases and discreetly in the production of beverages and foods. Its composition is notable for its total phenolic compounds (TPC) and antioxidant action, characteristics of great interest to the food industry, which seeks to meet the growing demand for balanced foods aimed at promoting health. The extraction of bioactive compounds requires efficient and economically viable processes. Therefore, the objective of this study was to optimize the extraction of bioactive compounds from E. grandiflorus leaves and evaluate their bioactive activities, their potential for application in yogurt, and characterize the centesimal composition of their leaves. The dehydrated leaves had the following composition (g/100 g): 29.81 g dietary fiber, 26 g total carbohydrates, 20.63 g protein, 11.60 g ash, 4.59 g lipids, 7.36 g moisture, vitamin C content of 4.47 ± 0.58 mg Aa/100 mL, caffeine content of 1.44 ± 0.09 mg/g, and pH of 5.99 ± 0.08. The best conditions for extraction were finer particle size (80 Mesh) together with 60% ethanol and a temperature of 80°C. The optimized conditions yielded an extract with a phenolic compound content of TPC 26.17 mg GAE/g, total flavonoids (TF) 25.86 mg CTE/g, DPPH 67.73 μmol TE/g, FRAP 125.32 μmol TE/g, and ABTS 119.74 μmol TE/g. Based on these parameters, the influence of leaf maturation stages in the young, mature, and old phases was evaluated. TPC ranged from 26.17 to 31.6 mg GAE/g, TF from 25.30 to 25.86 mg CTE/g. For carotenoids, values between 0.46 and 0.64 mg/g were found, and the total chlorophyll content varied between 2154.70 and 2732.28 mg/g. The TPC concentration is related to antioxidant activity DPPH 35.22–67.73 μmol TE/g, FRAP 125.32 μmol TE/g, ABTS 119.74 μmol TE/g. For antifungal activity, the extract from mature leaves obtained the best results, with inhibition between 24.12 and 48.74%. The flavonoid isoorientin presented the highest concentration in mature leaves, 5.605 ± 0.01 mg/g. Therefore, it was found that the efficiency of isoorientin extraction was higher than that observed in previous studies, evidencing the positive action of the method employed. The results suggest that the intensifying effect of ultrasound, combined with the experimental conditions adopted, played a decisive role in increasing the extraction yield. The extract from mature leaves also demonstrated antiglycemic activity and pancreatic lipase inhibition capacity. Using the extract from mature leaves at concentrations of 0.5%, 1%, and 2%, a positive effect of the extract on mold inhibition was observed compared to the control. The extract from E. grandiflorus demonstrated interesting biological activities that are partly related to the flavonoid isoorientin. The yogurt developed showed resistance to fungal growth during 28 days of storage, which is relevant for the preservation of dairy products. This highlights its potential for the development of functional foods with interesting characteristics in inhibiting mold that deteriorates dairy products, reinforcing its value as a natural source of bioactive compounds.