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Preparation and characterization of cellulose nanocrystals with high stability from okara by green solvent pretreatment assisted TEMPO oxidation

2023; Elsevier BV; Volume: 324; Linguagem: Inglês

10.1016/j.carbpol.2023.121485

1879-1344

Lu Tang, Bo Wang, Shiru Bai, Bei Fan, Liang Zhang, Fengzhong Wang,

Nanocomposite Films for Food Packaging

Because the traditional preparation methods of cellulose nanocrystals (CNCs) involve chemical pollution issues, in this study, two typical green solvents, alkali/urea solvent (AUS) and deep-eutectic solvent (DES), were used to dissolve insoluble soybean fibers (ISF) extracted from okara and prepare regenerated CNCs (AUS/CNC and DES/CNC), which were further modified by TEMPO oxidation (AUS/T-CNC and DES/T-CNC). The recoveries of AUS and DES were 82.58 % and 84.00 %, respectively. Chemical composition analysis showed high cellulose purity (>95 %) of the regenerated CNCs. FTIR, XRD and 13C NMR analysis indicated the cellulose structure and polymorph of CNCs. Thermal analysis revealed that the maximum degradation peak of regenerated CNC shifted to a lower temperature. AFM revealed that CNCs exhibited rod-like fiber structures, while AUS-pretreated CNCs exhibited some special spherical fibers. TEMPO oxidation showed an enhancement effect on the characteristics of AUS/T-CNC and DES/T-CNC; DES/T-CNC exhibited higher stability and apparent viscosity than AUS/T-CNC. The DES/T-CNC-based cryogel displayed a higher adsorption capacity for anthocyanin (0.40 g/g) and curcumin (1.09 g/g) with good controlled release capacity. These results indicated that green solvent pretreatment-assisted TEMPO oxidation is a new environmentally friendly and low-cost method for the preparation of CNCs and shows excellent potential in the field of drug loading and controlled release.