Functional, thermal and structural properties of fractionated protein from waste banana peel

Defatted banana peel powder was fractionated using the Osborne method to extract albumin, globulin, prolamin, and glutelin for physicochemical and functional characterization. The total recovery of protein was ∼89.76%. Albumin was the dominant one in terms of yield (62.4%) and protein content (65.15%) among all the fractions. The mean diameter of albumin (635.05 µm) and glutelin (642.62 µm) were significantly smaller than globulin (726.81 µm) and prolamin (986.45 µm). The highest water (1.86 ± 0.12 g/g), oil (1.97 ± 0.12 g/g) holding capacity, and emulsion capacity (59.27 ± 1.25%) were found for the albumin fraction. In contrast, the glutelin fraction showed the highest foaming capacity (19.13 ± 0.41%) and dispersibility (951.55 ± 3.83 g/kg). The denaturation temperature of protein fractions was found in the range of 30.31–82.08 °C. FTIR confirmed low carbohydrates and protein richness of albumin fraction. XRD revealed the crystalline nature of albumin (65%) and the amorphous nature of other fractions (41–45%). The morphology of all fractions was different, which influenced the functional characteristics.