Enhanced conditions for anthocyanin extraction from blackberry pomace under ultrasound irradiation

Abstract

The recovery of bioactive compounds from agro-industrial residues with green solvents in ultrasound-assisted extraction (UAE) processes represents an interesting alternative from environmental and economical perspectives. Here we investigated optimal conditions to improve the extraction of anthocyanins from blackberry pomace. The experimental data were fitted to the second-order polynomial model to obtain the regression coefficients, and three-dimensional (3-D) response surface plots were considered to represent the relationships between each variable on the response of total monomeric anthocyanin (TMA) content. The ultrasound-assisted process at an ultrasound amplitude of 40% for 10 min and a concentration of 25 mg/L resulted in the maximum TMA concentration of 1.39 ± 0.02 mg Cy3GlE /g. At these extraction conditions, the extract presented total polyphenol and flavonoid contents of 44.12 ± 0.17 mg GAE /g and 63.25 ± 0.53 mg QE /g, respectively. A total of 31 individual compounds, including anthocyanins, flavonols, and phenolic acids, were identified in the extract. Concentrations of cyanidin-3-glucoside and caffeic, gallic, and ellagic acids were 2.38 ± 0.09, 0.47 ± 0.01, 0.55 ± 0.01, and 0.48 ± 0.01 mg/g, respectively. Compared to the conventional extraction, the UAE represented an increase of 20.87% in total anthocyanins. Thus, the UAE at suitable conditions is suggested to recover bioactive compounds from blackberry pomace. Practical ApplicationsThe use of blackberry pomace to extract bioactive compounds is promising because it uses a by-product from the fruit processing industry. This study presents an innovative proposal of optimal process conditions to recover anthocyanins from blackberry pomace under ultrasound irradiation. The use of green solvents, as water, in ultrasound-assisted extraction (UAE) processes, represents an interesting alternative from environmental and economical perspectives, UAE process is a favorable, fast, efficient, and environmentally friendly method. The obtained blackberry pomace powder is an interesting ingredient to food and pharmaceutical industries, mainly due to the elevated concentration of added-value compounds. Besides the high amount

Phytochemicals Determination, and Antioxidant, Antimicrobial, Anti-Inflammatory and Anticancer Activities of Blackberry Fruits

“…Albert et al for instance, determined 6.43 mg Cy-3-glu eq./g d.w. in ultrasound-assisted ethanolic extracts and 80% ethanol as solvent [ 10 ]. However, lower anthocyanin recovery was obtained by Siqueira dos Santos et al with a total anthocyanin recovery of 1.39 mg Cy-3-glu/g d.w [ 33 ].…”

“…Both were previously identified by Oszmianski et al in wild blackberry fruits [ 7 ]. Ellagic acid appeared at a retention time of 8.726 min and it is considered the main phenolic compound present in blackberry fruits by numerous authors [ 7 , 33 , 36 ]. Nevertheless, the most abundant phenolic acid detected in this work has been ellagic acid pentoside, with a total concentration of 53.6 μg/g d.w. as the sum of its isomers.…”

“…Three catechin derivatives, such as epicatechin and two B-type procyanidin dimers (peaks 14, 10 and 15, respectively), were also tentatively identified. All of them, were previously described in blackberry fruits [ 33 , 36 , 37 , 38 ]. Furthermore, at retention times of 9.984 and 10.509 min, two molecules with molecular formula C 30 H 36 O 11 were identified as kadsurarin and its isomer, and at a retention time of 10.74 min, a compound proposed as kadsurenin B was also detected.…”

“…On the other hand, there are authors who have achieved superior antioxidant activity values. Santos et al, for example, prepared an extract using ultrasound-assisted extraction with 52.36 mg GAE/g d.w. measured by F-C assay but, referring to TEAC values, there were no significant differences with our extract (555.62 versus 576.6 μM TE/g d.w.) [ 33 ]. Wajs-Bonikowska et al obtained an ethanolic extract of blackberry pomace with 94.43 mg GAE/g d.w. which also presented significantly higher antioxidant activity by ABTS (1011.22 μmol TE/g d.w.) [ 53 ].…”

Trends in maintaining postharvest freshness and quality of Rubus berries

“…Ultrasound‐assisted SCT yielded enhanced antioxidants as compared to other applied treatments (Reátegui et al., 2014). In a recent study, ultrasound treatment assisted in significantly enhancing anthocyanin production (20.87%) from blackberry pomace as compared to the traditional method of extraction (Santos et al., 2022). Contrastingly, ultrasound also helps in the dehydration of blackberries for long‐term preservation.…”