Valorization of discarded red beetroot through the recovery of bioactive compounds and the production of pectin by surfactant-assisted microwave extraction

Discarded red beetroot (DRB) is an organic waste generated in the food industry. This study focused on valorization of DRB through recovery bioactive compounds. The characterization juice confirmed a higher content antioxidants (DPPH 504 ± 24 μmol TE/L, FRAP 10920 440 ABTS 22012 592 TE/L), phenolic compounds (1789 56 mg GAE/L), flavonoids (471 17 CE/L) and betalains (1426 mg/L) than commercial juices. pomace contains pectin that was recovered by microwave extraction aided surfactant (polyethylene glycol, PEG4000). Conditions (temperature, time concentration) for galacturonic acid (GalA) or pectooligosaccharides (POS) were optimized central composite experimental design. POS extracted at high temperatures (160 °C, 5.3 min, 8.4 g PEG4000/L, yield 271.2 POS/kg dry pomace). In comparison, favored moderate conditions (137 5 2.5 120.1 GalA/kg freeze-dried hydrolysates revealed solid obtained under temperature °C) showed GalA (49.5%) lower neutral sugars (11.4%), as degrades pentoses. can be considered high-methoxyl pectin, degree esterification 50%. FTIR spectra functional groups consistent with pectin. MALDI-TOF-MS analysis presence oligosaccharides hexoses pentoses different structures degrees polymerization. Thus, DRB, low-value vegetable waste, converted into high-value-added bioproducts biorefinery framework.