Influence of Extraction Conditions on Ultrasound-Assisted Recovery of Bioactive Phenolics from Blueberry Pomace and Their Antioxidant Activity

Abstract

The increase in diet-related chronic diseases has prompted the search for health-promoting compounds and methods to ensure their quality. Blueberry pomace is a rich yet underutilized source of bioactive polyphenols. For these high-value bioactive molecules, ultrasound-assisted extraction (USAE) is an attractive and green alternative to conventional extraction techniques for improving purity and yields. This study aimed to assess the impact of USAE parameters (sonication time, solvent composition, solid/liquid ratio, pH and temperature) on the recovery of phenolic compounds from blueberry pomace and antioxidant activity of the extracts. Total phenolic, flavonoid and anthocyanin contents (TPC, TFC and TAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity were analysed. USAE in 50% ethanol/water was the most efficient, yielding the highest TPC (22.33 mg/g dry matter (DM)), TFC (19.41 mg/g DM), TAC (31.32 mg/g DM) and DPPH radical scavenging activity (41.79 mg Trolox/g DM). USAE in water showed the lowest values even at low (1/40) solid/liquid ratio (7.85 mg/g DM, 3.49 mg/g DM, and 18.96 mg/g DM for TPC, TFC and TAC, respectively). Decreasing the solid/liquid ratio in water or 50% ethanol significantly increased TPC, TFC, TAC and DPPH radical scavenging. With ethanol, increasing the temperature in the range 20–40 °C decreased TPC but increased TFC and DPPH radical scavenging activity. Anthocyanin profiles of water and ethanolic extracts were qualitatively similar, consisting of malvidin, delphinidin, petunidin and cyanidin. These findings indicate that USAE is a method of choice for extracting high-value bioactive phenolics from blueberry pomace. Selective enrichment of different phenolic fractions is possible under select extraction conditions.

Coencapsulation of Polyphenols and Anthocyanins from Blueberry Pomace by Double Emulsion Stabilized by Whey Proteins: Effect of Homogenization Parameters

“…The double emulsion contained a polyphenol-rich aqueous extract of blueberry pomace (W 1 ), which was emulsified in corn oil with polyglycerol polyricinoleate (PGPR) to form the primary emulsion W 1 /O, which was subsequently dispersed in a whey protein isolate (WPI) solution (W 2 ) to form the double emulsion. In keeping with the green extraction technology which was developed to extract the phenolic compounds from blueberry pomace [ 32 ], the other ingredients of the emulsions were selected because they are safe for human consumption and environmentally friendly. The emulsifiers PGPR and WPI are both generally recognized as safe (GRAS denomination) [ 33 , 34 ].…”

EXTRACTION OF MONOMERS OF HYDROLYSABLE TANNINS FROM PODS OF Libidibia ferrea (Mart. ex Tul.) L. P. QUEIROZ: EFFECTS OF SOLVENT AND AMOUNT OF DRUG USING RESPONSE-SURFACE METHODOLOGY AND DESIRABILITY PROFILE

“…Ethanol, used in different proportions in this study, is effective for extraction of polyphenols, and is less toxic for use. 27 As for the method, in turbolysis extraction occurs simultaneously with particle size reduction due to the applied shear forces. The reduction of particle size and the disruption of cells favor the process, resulting in shorter extraction time and near exhaustion of the drug.…”

Optimization of Ultrasonic-Assisted Extraction of Total Phenolics from Citrus aurantium L. Blossoms and Evaluation of Free Radical Scavenging, Anti-HMG-CoA Reductase Activities

“…Ultrasonic-assisted extraction of total phenolics from CAB was carried out with an ultrasonic apparatus (KQ-5200DE, Kunshan ultrasonic Co. Ltd., Suzhou, China), and ultrasound frequency and ultrasound power were set as 40 kHz and 100 W, respectively. Each 5 g of sample powder was placed into a volumetric flask (250 mL), then extracted with various ethanol concentrations (30, 40 50, 60, 70, 80%), temperatures (30,40,50,60, 70, 80 °C), liquid-solid ratio (15,20,25,30,35, 40 mL/g) for various times (15, 30, 45, 60, 75, 90 min) respectively. The extracts were filtered, combined, after which extraction solvent was replenished to bring the final volume of the extract to 250 mL.…”

“…Ultrasonic-assisted extraction utilizes the cavitation effect, mechanical effect and thermal effect of ultrasonic wave to extract biological active components rapidly and fully, which can also enhance the biological activities of extracts [22,23]. As a novel technology, ultrasonic-assisted extraction has been proposed by many researchers, such as phenolic compounds from Justicia spicigera leaves [24], blueberry pomace [25], Oryza sativa L. 'Violet Nori' [26], Brosimum alicastrum leaves [27], Acer Truncatum leaves [28].…”