Green extraction of bioactive components from carrot industry waste and evaluation of spent residue as an energy source

Abstract

Carrot processing industries produce 25–30% of waste in the form of carrot rejects, peels, and pomace which contain a large amount of high-value bioactive components. Green extraction of the bioactive components from carrot rejects with green solvents using closed-vessel energy-intensive microwave-assisted extraction was the objective of this work. In this work, three experimental studies were implemented. One uses 8 different green solvents for maximum yield of bioactive using green technology, and the other for the optimization of Microwave-assisted Extraction (MAE) parameters to enhance the bioactive components yield. Response Surface Methodology was employed to optimize the processing parameters including temperature, time, solid to solvent ratio, and solvent type. The optimized extraction conditions: treatment temperature of 50 °C for 5 min gave a significantly higher yield of total carotenoids (192.81 ± 0.32 mg carotenoids/100 g DW), total phenolic (78.12 ± 0.35 g GAE/100 g DW), and antioxidants by FRAP (5889.63 ± 0.47 mM TE/100 g DW), ABTS (1143.65 ± 0.81 mM TE/100 g DW), and DPPH (823.14 ± 0.54 mM TE/100 g DW) using a solvent combination of hexane and ethanol (1:3) with solid to solvent ratio of 1:40 (w/v). This green technology in combination with GRAS solvents promoted the best recovery of bioactive from carrot rejects. Moreover, the solid residue remained after the extraction of bioactive components exhibited higher carbon content (46.5%) and calorific value (16.32 MJ/kg), showcasing its potential to be used as an energy source.

Comparative analysis of physicochemical characteristics, bioactive components, and volatile profile of sour cherry (Prunus cerasus)

“…The FRAP assay was performed according to the method followed by Kaur et al (2022) with slight modifications. The stock solutions of 300 mmol/L acetate buffer (pH 3.6), 10 mmol/L 2,4,6-Tris(2-pyridyl)-s-triazine (TPTZ) in 40 mmol/L HCl, and 20 mmol/L FeCl 3 solutions were mixed in a ratio of 10:1:1 and allowed to incubate at 37 • C for 2 h. An aliquot of 50 μL cherry extract was mixed with 200 μL of the warmed FRAP working solution, allowed to incubate at 37 • C for 30 min, and absorbance was measured at 593 nm.…”

Comparative Antioxidant Activity and Untargeted Metabolomic Analyses of Sour Cherry Cultivars Based on Ultra-Performance–Time of Flight–Mass Spectrometry

“…The total antioxidant activity was conducted using three different assays (ABTS, FRAP, and DPPH) [ 41 ]. Antioxidant capacity was assessed with DPPH, FRAP, and ABTS as per the previously published method [ 42 ]. The details of the extraction procedures have been described in an earlier report [ 16 ].…”

Comparative Antioxidant Activity and Untargeted Metabolomic Analyses of Sour-Cherry Cultivars Based on UPLC-TOF-MS

“…The total antioxidant activity was done using three different assays (ABTS, FRAP, and DPPH). Antioxidant capacity was assessed with ABTS as per the previously published method [41]. The details of the extraction procedures have been described in an earlier report [16].…”