Extraction of Stable Antioxidant Compounds from Banana Inflorescences Using Eco-friendly Methods

Abstract

For each ton of bananas harvested, 160 kg of inflorescences are discarded. Inflorescences of Musa × paradisiaca, AAB group, Dwarf Prata cultivar, were subjected to extraction for the recovery of natural products using environmentally benign solvents and processes: steam distillation (SD); Soxhlet with water (AE), ethanol (EtOH), and 2-methyltetrahydrofuran (2-MeTHF); and supercritical fluid extraction (SFE) with CO₂. The AE process led to the highest yield (26.4%), total phenolic content (TPC), and FRAP antioxidant power of the fresh extracts. The yields obtained using SFE (3.9%), EtOH (11.1%), and 2-MeTHF (11.2%) were lower; however, these extracts maintained a stable TPC after 6 months of storage, whereas the TPC of AE decreased. The total flavonoid contents were the highest ever reported in the literature for banana inflorescence (32.1 mg CE/g extract, SFE). The 2-MeTHF and AE extracts exhibited the highest Trolox equivalent antioxidant capacity and oxygen radical absorbance capacity, respectively. The choice of extraction method and solvent depends on the intended application of the extract. If maximizing yield and antioxidant power is the goal, hot water extraction is preferable. For preserving stable phenolic compounds, 2-MeTHF extraction is more suitable. The SFE technique is ideal for concentrating flavonoids.