Optimization and comparison of nonconventional extraction techniques for soluble phenolic compounds from brocade orange (Citrus sinensis) peels

Abstract

Brocade orange (Citrus sinensis L. Osbeck) peels (BOPs) are rich in a variety of phenols with multiple and strong bioactivities. This study sought to utilize a response surface methodology to optimize the parameters of accelerated solvent extraction (ASE) to obtain phenolic extracts from BOPs. Total phenolic and flavonoid content (TPC and TFC), profiles, and antioxidant activities of extracts for free, esterified-, and glycosylated-bound phenols from ASE were compared with those derived from Soxhlet extraction (SE) (80 • C, 6 h) and heatreflux extraction (HRE) (80 • C, 3 h). Maximum practical TPC and TFC under optimal ASE conditions (15 min, 108 • C, 82 bar, and three cycles) were determined to be 32.82 mg gallic acid equivalents/dry weight (DW) and 10.25 mg rutin equivalents/DW, respectively. The profiles, contents, and corresponding bioactivities of the extracts significantly depended on extraction method, particularly with regard to phenolic fraction. Generally, ASE and HRE were associated with higher levels of extraction efficiency and higher quality targeted bioactive compounds with stronger antioxidant activity. More importantly, ASE represents a simple, efficient, and time-saving technique for the extraction of phenols. Furthermore, the finding that different phenolic fractions contain variable profiles and contents of phenols is useful for efforts to obtain targeted individual bioactive ingredients and make better use of biomass residues.

Antioxidant and Antifungal Activities and Characterization of Phenolic Compounds Using High-Performance Liquid Chromatography and Mass Spectrometry (HPLC-MS) in Empetrum rubrum Vahl ex Willd.

“…According to Dias et al [ 41 ], the Soxhlet apparatus was chosen to carry out a conventional technique to determine the total phenolic content and antioxidant capacity, making this technique an effective method for obtaining bioactive compounds. It should be mentioned that the temperature of 65 ± 5 °C employed in the Soxhlet apparatus is related to another study, because in that study the extracts were obtained employing higher temperatures of 80 °C, to evaluate antioxidant activities [ 42 ].…”

Exploring Phenolic Compounds in Crop By-Products for Cosmetic Efficacy

“…The use of these solvents mixed makes them suitable for enhancing extraction yields [ 68 ]. Therefore, although this Soxhlet technique has been widely used for phenolics extraction, such as in broccoli plants [ 69 , 70 ], citrus [ 71 ], grape [ 72 ] and artichoke [ 73 ], the choice of right solvent for specific phenolic compounds should be determined since there is no universally best solvent mix.…”

The impact of different drying methods on the physical properties, bioactive components, antioxidant capacity, volatile components and industrial application of coffee peel

“…For example, compared with SD and HAD samples, VFD and VD treatments could contain high levels of total phenols, flavonoids, anthocyanidins and antioxidant activities ( Jiamjariyatam et al, 2022 , Thy Minh Kieu et al, 2020 ). Moreover, different drying techniques can also greatly affect the volatile compounds ( Wang et al, 2022 ). Aroma is crucial, influencing the flavor and commercial appeal of agricultural products (Song et al, 2020).…”