Modeling and Optimization of Phenolic Compounds from Sage (Salvia fruticosa L.) Post-Distillation Residues: Ultrasound- versus Microwave-Assisted Extraction

Abstract

The essential oil production of Salvia fruticosa L. generates considerable amounts of post-distillation solid residues (PRES) which are rich in phenolic compounds. In the present work, the recovery of phenolic antioxidants from PRES by using Microwave-Assisted Extraction (MAE) and Ultrasound-Assisted Extraction (UAE) were separately optimized, according to the Box–Behnken experimental design. The optimization was based on extraction yield, total phenolic content (TPC), total flavonoid content (TFC), rosmarinic acid (RMA), carnosol (CARO), carnosic acid (CARA), and antioxidant activity. The optimal processing parameters were 72% and 68% ethanol, a 15- and 10-min extraction time, a 40 °C and 47 °C extraction temperature, and a 1:30 and 1:10 solid-to-solvent ratio, for MAE and UAE, respectively. Results showed that the levels of RMA, CARO, and CARA in UAE extracts were influenced mainly by ethanol concentration, extraction time, and extraction temperature, while MAE extracts were only influenced by the first two factors. Experimenting with the optimal conditions revealed MAE as more effective than UAE in the recovery of RMA and CARA. The experimental values were in good agreement with the predicted ones, indicating model efficacy in MAE and UAE optimization to effectively extract phenolic compounds from PRES for their further application in food and pharmaceutical industries.

The Use of Ultrasound-Assisted Maceration for the Extraction of Carnosic Acid and Carnosol from Sage (Salvia officinalis L.) Directly into Fish Oil

“…Maceration U and the first step of maceration H were carried out at room temperature (19–22 °C), and then after homogenization, in the case of the second step of maceration H, the next step of free maceration was carried out at 4 °C cooling conditions. Extraction at elevated temperature was intentionally not carried out, as an increase in temperature could cause a decrease in the content of carnosic acid and carnosol, which is consistent with the observations of other researchers [ 9 ]. Then, after maceration (in both methods: U and H), the oil phase was separated from sage, and carnosic acid and its derivative, carnosol, as well as rosmarinic acid, were determined in the filtered macerate.…”

“…Irrespective of the type of solvent used for the determination, the highest carnosic acid and carnosol contents in the macerate, respectively 147.5 mg/100 g and 42.7 mg/100 g of the macerate, were obtained after 60 min assisted maceration ultrasound U using a higher power of the device (320 W). Higher contents in the extracts after the application of ultrasounds at the level of 108.3 mg/g of carnosic acid and 49.6 mg/g of carnosol were obtained by Irakli et al [ 9 ], where the active compounds were extracted from another species of sage directly into ethanol, not into oil. On the other hand, apart from earlier studies [ 22 ], in which during maceration assisted by homogenization, carnosic acid and carnosol were extracted from sage into the oil phase and showed antioxidant properties in fish oil, no data have been published on the extraction of carnosic acid and carnosol directly from sage to edible oils.…”

“…In addition, it is unstable, especially in organic solvents, with an acidic environment significantly increasing its stability [ 8 ]. Also, longer extraction time [ 9 ] and elevated temperature accelerate the decomposition of carnosol compounds [ 9 , 10 ]. However, they are much more stable in food, including fats and oils [ 11 , 12 , 13 ].…”

Sustainable Recovery of Phenolic Compounds from Distilled Rosemary By-Product Using Green Extraction Methods: Optimization, Comparison, and Antioxidant Activity

“…Major components of the SWR extracts, RMA, CARO, and CARA, were quantified on a Shimadzu Nexera HPLC system (Kyoto, Japan) equipped with a diode array detector and a single quadrupole mass spectrometer (LCMS-2020), which was operated with an electrospray ionization (ESI) interface. Separations were performed on a Poroshell 120 EC-C 18 analytical column (4.6 × 150 mm, 4 µm), according to a method described in detail by Irakli et al [ 45 ]. Mass acquisitions were performed by targeted selective ion monitoring (SIM) scanning mode.…”

“…The determination of total phenolic content (TPC), total flavonoid content (TFC), and antioxidant capacity of the extracts was performed using spectroscopic methods as described by Irakli et al [ 45 ]. The TPC, TFC, and antioxidant activity (ABTS, DPPH, and FRAP) were evaluated as mg gallic acid, catechin, and Trolox equivalents, respectively, per g of dried extract.…”