Synergistic effect of ultrasound and citric acid treatment on functional, structural and storage properties of hog plum (Spondias mombin L) bagasse.

Abstract

A novel approach in promoting the valorisation of fruit waste as potential bio-ingredients in food applications is gaining research attention in recent times. In the present study, hog plum bagasse (HPB) treated with citric acid alone (0.12 dm3, 99.0% purity) and in synergistic treatment with ultrasound (40 KHz, 400 W, 0.348 W/cm3, 60 min, 80 °C). Treated samples were evaluated for proximate and lignocellulose composition, functional, bioactive, structural, morphology and microbial properties, while the untreated samples served as control. HPB showed varied proximate values with treatment effect. Notably, a significant reduction (42.06%) was observed in fibre content. A similar reduction was observed in the hemicellulose and lignin fraction but improved the yield of the cellulose component. Furthermore, treatment increased bulk density (0.120-0.131 g/cm3), water absorption capacity (5.60-6.35 g/g), swelling power (8.85-9.94 g/g) and solubility index (1.01-2.32%) but reduced oil absorption capacity (7.50-4.15 g/g). All colour parameters were reduced with treatment, while the total phenolic compound and antioxidant capacity of treated bagasse improved by 24.70% and 45.37%. Fourier transform infra-red spectroscopy alterations were observed in the absorption spectra with treatment, while scanning electron microscopestructure in treated samples showed cavity formation. Also, the microbial population was reduced to a non-detectable level after treatment. Ultrasound-assisted treatment of HPB holds a valorisation potential for its food application by relevant agro-based industries.