IMPACT OF CONVENTIONAL/NON-CONVENTIONAL EXTRACTION METHODS ON THE PHENOLIC COMPOUNDS AND ANTIOXIDANT CAPACITY OF CIRIGUELA RESIDUE

In the last decades, economic and environmental problems have caused growing concerns with the large volume of waste generated in the food industries. The residue of the ciriguela presents/displays bioactive compounds, however they are discarded in the environment. The impact of different extraction methods (maceration, homogenizer-assisted, microwave-assisted and ultrasound-assisted) on polyphenols of ciriguela residue was studied. Maceration extraction: 1.25g of ciriguela residue was extracted in 75mL of ethanol 80% by 4h. Homogenizer-assisted extraction: 0.5g of ciriguela residue were extracted in 30mL of ethanol 80% by using an Ultra-turrax at 5000×g for 3min. Ultrasound-assisted extraction was performed with an ultrasonic-bath (40 kHz and 35 ºC) 0.33g of residue were sonicated in 20mL of ethanol 80% for 60 min. Microwave-assisted extraction: 0.33g of residue were extracted in 20mL of ethanol 80% in microwave for 60min. After, the extracts were filtered and collected in amber glass until further analysis. The contents of phenolics compound using the Folin-Ciocalteau reagent and expressed in mg/100g, as well as the antioxidant capacity by DPPH and ABTS were determined. Phenolics compound (mg/100g) of extract of ciriguela residue obtained were; maceration (23.21±0.40), homogenizer (22.75±0.51), ultrasound (25.97±0.42) and microwave (22.89±0.13). Regarding the DPPH and ABTS assay, the extracts obtained showed inhibition percentage: maceration (73.81% ± 1.48 / 68.09% ± 0.48), homogenizer (71.48% ± 2.55 / 51, 83% ± 1.26), ultrasound (56.13% ± 1.68 / 53.84% ± 0.29) and microwave (64.08% ± 1.38 / 67.68% ± 0.38), respectively. All extracts showed large amounts of phenolic compounds, thus, ciriguela residue is a potential source of active ingredients such as polyphenols. The ultrasound-assisted extraction technique was more effective in extracting these compounds. Maceration and microwave-assisted extraction produced the highest antioxidant capacity. These results demonstrate the efficacy of the ciriguela residue in the extraction of bioactive compounds with better antioxidant capacity.