Effect of microwave-assisted alkaline treatment on physicochemical, functional and structural properties of hog plum (Spondias mombin L.) bagasse

Abstract

In the present study, the use of microwave-assisted alkaline treatment (MAAT) to characterize hog plum (Spondias mombin L) bagasse (HPB) was investigated. HPB treated with sodium hydroxide (0.015, 0.025 and 0.03 M), and assisted with microwave treatment (600 W, 2400 MHz) for 5 min was analyzed for proximate (moisture, protein, fat, ash, fiber and carbohydrate content), lignocellulosic component (cellulose, hemicellulose and lignin), color parameters, functional (bulk density, water-WAC and, oil absorption capacity-OAC, swelling power and solubility index), structural (XRD) and morphological (SEM) properties with an untreated sample as the control. MAAT significantly (p < 0.05) showed a varied influence on proximate composition, but notably reduced crude fiber. Similarly, treatment reduced hemicellulose and lignin component, but increased cellulose content. Furthermore, treatment reduced color, but varied in functional properties of loose (0.065–0.137 g/cm3) and pack (0.113–0.167 g/cm3) bulk density, WAC (5.63–6.20 g/g) and OAC (7.10–4.97 g/g). An increase in swelling power (10.46–12.37 g/g) and solubility index (1.03–2.57%) was observed with treatment. Crystallinity pattern increased with treatment with peaks showing type I cellulose, while the morphological structure of delignified fiber showed increased porosity or pitched region with increasing treatment. The potential use of hog plum bagasse after MAAT for food application is technically feasible.