Comparison of cellulose nanocrystals from pineapple residues and its preliminary application for Pickering emulsions

Extraction of insoluble soybean fiber by alternating ultrasonic/alkali and its improved superior physicochemical and functional properties

Okara, as a by-product of soybean processing, is rich in insoluble dietary fiber (IDF), which is a carbohydrate polymer with various insoluble polysaccharides. Nowadays, the extraction of IDF with excellent functional properties has become a research hotspot. In this work, we further proposed an alternating alkali/ultrasound method for the efficient extraction of IDF. The sequential treatments of alkali (A-ISF), alkali-ultrasonic (AU-ISF), ultrasonic-alkali (UA-ISF), ultrasonic-alkali-ultrasonic (UAU-ISF) and alkali-ultrasonic-alkali (AUA-ISF) were applied to extract insoluble soybean fiber (ISF). FTIR and XRD results proved the typical structure of ISFs, and TGA results demonstrated the improved thermal stability of UAU-ISF and AUA-ISF. Chemical composition measurement showed that UAU-ISF and AUA-ISF exhibited higher cellulose content (>83 %). SEM results revealed that ultrasonic treatment led to a decomposition of okara matrix and significant porous structure in ISFs with an amplified collapse effect, resulting in an increase of the pore size of ISFs, and strengthening the properties of UAU-ISF and AUA-ISF in higher water (>15 g/g)/oil (>12 g/g) holding capacities, cholesterol binding capacity (>36 mg/g), and cation exchange capacity (>0.3 mmol/g), thus providing new insights for the preparation of ISF with high functional properties that are beneficial for human intestinal health.

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

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.

Food-Grade Oil-in-Water (O/W) Pickering Emulsions Stabilized by Agri-Food Byproduct Particles

In recent years, emulsions stabilized by solid particles (known as Pickering emulsions) have gained considerable attention due to their excellent stability and for being environmentally friendly compared to the emulsions stabilized by synthetic surfactants. In this context, edible Pickering stabilizers from agri-food byproducts have attracted much interest because of their noteworthy benefits, such as easy preparation, excellent biocompatibility, and unique interfacial properties. Consequently, different food-grade particles have been reported in recent publications with distinct raw materials and preparation methods. Moreover, emulsions stabilized by solid particles can be applied in a wide range of industrial fields, such as food, biomedicine, cosmetics, and fine chemical synthesis. Therefore, this review aims to provide a comprehensive overview of Pickering emulsions stabilized by a diverse range of edible solid particles, specifically agri-food byproducts, including legumes, oil seeds, and fruit byproducts. Moreover, this review summarizes some aspects related to the factors that influence the stabilization and physicochemical properties of Pickering emulsions. In addition, the current research trends in applications of edible Pickering emulsions are documented. Consequently, this review will detail the latest progress and new trends in the field of edible Pickering emulsions for readers.