EFFECT OF EXTRACTION TIME ON ULTRASOUND-ASSISTED EXTRACTION OF BIOACTIVE COMPOUNDS FROM WILD CARURU (Amaranthus viridis)

Caruru (Amaranthus viridis), a widely distributed unconventional food plant in Brazil, possesses well-documented health benefits. However, its consumption and potential for technological applications remain largely untapped. To address this, leveraging emerging technologies like Ultrasound-Assisted Extraction (UAE), particularly with green solvents such as ethanol, water, and their mixtures, offers a promising strategy for adding value to this underutilized resource. Thus, this study aimed to extract bioactive compounds from dried and milled caruru (DMC) using UAE.The ultrasound-assisted extraction (UAE) was conducted using a 50% ethanol-water mixture (w/w) with a constant solvent-to-feed (S/F) ratio of 50. A kinetic curve was constructed using extraction times of 0, 3, 6, 9, 12, 18, 24, and 30 minutes, under a nominal ultrasound power of 500 W. The global yield was determined by calculating the mass ratio of the dry extract to the initial dry plant material. Furthermore, the total reducing capacity (TRC) was assessed using the Folin-Ciocalteu method. Between the extraction times of 3 and 30 minutes, there was a 28.63% increase in total extract mass and a 30.77% increase in the yield of total reducing capacity. The highest yields for both total extract mass and phenolic compounds were observed at 30 minutes, reaching 15.51 ± 0.35 g extract/100 g DMC and 12.16 ± 0.9 mg/g DMC, respectively. However, the Tukey test (at a 5% significance level) indicated no significant difference in yields from 9 minutes of extraction onward, suggesting that the process likely entered a diffusion-controlled phase beyond this point. This study demonstrates that ultrasound-assisted extraction (UAE) is an effective method for obtaining valuable compounds from caruru. More importantly, these findings highlight a significant opportunity for the sustainable valorization of non-conventional food plants, such as caruru. By developing efficient extraction processes for typically discarded or underutilized resources, this work contributes to reducing waste and creating new value chains in the food and nutraceutical industries, promoting a more circular and sustainable bioeconomy.