Abstract
In the present study, valorization of yarrow (Achillea millefolium) by-product from the filter tea industry was investigated through the application of subcritical water for the extraction of bioactive compounds. The influence of different process parameters (temperature 120–200 °C, extraction time 10–30 min, and HCl concentration in extraction solvent 0–1.5%) on extract quality in terms of content of bioactive compounds and antioxidant activity was investigated. Optimal conditions of the extraction process (temperature 198 °C, extraction time 16.5 min, and without acidifer) were determined and, when applied, the most efficient exploitation of by-products is achieved, that is, attainment of extracts rich in total phenols and flavonoids and high antioxidant activity. In addition, by applying the high performance liquid chromatographic analysis, the content of chlorogenic acid was determined as well as the hydroxymethylfurfural content in obtained extracts. The results demonstrated that subcritical water can be successfully used for utilization of yarrow by-products for obtaining extracts rich in antioxidants.
Highlights
Yarrow (Achillea millefolium L.) as a widespread plant coming from the Asteraceae family has a long history of use, beginning in ancient times when it was used as a wound-healing remedy
In order to estimate the applicability of Subcritical water extraction (SWE) for extracting phenolic compounds from the herbal dust of A. millefolium, the SWE extraction was performed at different process parameters defined by
In order to potentially improve the efficiency of extraction of bioactives and potential hydrolysis and the release of polyphenolic compounds from glycosides with minimal formation of undesired components and attainment of extracts rich in polyphenols, this study investigated the parameters in the following ranges: temperature 100−200 ◦ C, extraction time 10−30 min, and HCl concentration 0–1.5%
Summary
Yarrow (Achillea millefolium L.) as a widespread plant coming from the Asteraceae family has a long history of use, beginning in ancient times when it was used as a wound-healing remedy. When the temperature and pressure increase to 250 ◦ C and 50 bar, respectively, the dielectric constant drops to ε = 27, making it similar to organic solvents such as methanol (ε = 33), ethanol (ε = 24), acetone (ε = 20.7), and acetonitrile (ε = 37) Under such conditions, the water will behave to organic solvents, dissolving a wide spectrum of components with low and medium polarity [16]. The optimization can be achieved by applying the traditional one-variable-at-a-time technique, which includes monitoring the influence of one factor on desired responses while other factors remain constant. This approach includes a high number of experiments, which is time-consuming and alsoresults in increased costs. To the best of our knowledge, this is the first study that investigates a green optimization process of yarrow by-product sourced from the industry and represents a contribution to green growth and the circular economy
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