Isolation of cellulose and synthesis of nanocellulose from banana (Musa acuminata) rachis fibre and their utilization and characterization as bioactive aerogels

The objective of the present study was to valorize banana rachis that is generated as waste after removal of banana fingers from the stalk. Rachis of Musa acuminata was used to synthesize cellulose fibre (CF) and nanocellulose (NC), and bioactive aerogels were developed from CF and NC. CF and NC were characterized for particle size, functional groups, crystallinity, thermal analysis, and morphology. The particle size of NC was ⁓122 nm. The bioactive compounds from butterfly pea flower (Clitoria ternatea) were extracted in ethanol. CF and NC were treated with polyvinyl alcohol and butterfly pea flower extract to develop aerogels by physical cross-linking method and compared with aerogel with control that had no flower extract for various properties. The density of aerogels decreased (<0.1 g/cm³), while the porosity increased (>90%) after the addition of CF and NC. The water absorption capacity of aerogels with CF and aerogels with CF/NC was 1116.99% and 1821.66%, respectively, whereas aerogels made with pure PVA had the lowest water absorption capacity of 460.66%. The antioxidant activity of the aerogels reduced due to dilution effect of CF and NC. The in vitro release study showed that the developed aerogels preserved their integrity and allowed for gradual release of the bioactive compounds. Thus, the results indicated that CF and NC synthesized from banana rachis are useful for bioactive aerogel development that could effectively encapsulate bioactive compounds and help in their controlled release. The aerogels have scope to be used as bioactive delivery vehicle for application in food packaging structures.