To investigate the optimal delivery system of quercetin, in this paper, cellulose nanocrystals (CNCs) extracted from rice bran were used to stabilize the Pickering emulsion and Pickering emulsion gels (PEGs) with quercetin. To compare the emulsion properties, stability, antioxidation activity, encapsulation rate, and bioaccessibility of the quercetin, four emulsions of CNC Pickering emulsion (C), CNC Pickering emulsion with quercetin (CQ), CNC Pickering gel emulsion (CG), and CNC Pickering gel emulsions with quercetin (CQG) were prepared. All four emulsions exhibited elastic gel network structure and good stability. The quercetin significantly reduced the particle size, increased the stability, and improved the antioxidant capacity of CQ and CQG. Compared to C and CG, the ABTS⁺ radical scavenging capacities of CQ and CQG were respectively enhanced by 46.92% and 3.59%. In addition, CQG had a higher encapsulation rate at 94.57% and higher bioaccessibility (16.17) compared to CQ. This study not only indicated that CNC from rice bran could be exploited as an excellent stabilization particle for Pickering emulsions, but also provided a highly stable and bioaccessible delivery system for water-insoluble functional active factors.

Rice bran, a byproduct of rice milling, comprises 12–14% protein. The foaming properties and associated mechanisms of the composite rice bran protein system were not well studied. In this study, a composite protein system composed of rice bran protein (RBP)–sodium caseinate (NaCas) and rice bran protein nanoparticles (RBPNs)–sodium caseinate (NaCas) was investigated. The results showed that the synergistic effect of RBP and NaCas increased the foaming stability of the composite solution up to 83.77 ± 2.75%. Moreover, the foaming capacity and foaming stability of the RBPNs-NaCas composite solution were up to 177.50 ± 3.53% and 80.28 ± 0.39%, respectively. The physicochemical properties results revealed that the particle size volume peaks of RBP-NaCas and RBPNs-NaCas were mainly concentrated at 55.7 nm and 197.1 nm, and RBPNs-NaCas showed a wider single peak particle size distribution. The ζ-potential values of RBP-NaCas and RBPNs-NaCas were changed to −35.5 ± 0.07 mV and −27.2 ± 0.28 mV after complexation. The apparent viscosity and consistency factor of RBP-NaCas decreased by 31.1% compared to RBP, while RBPNs-NaCas displayed similar parameters to the single proteins. The interfacial rheological test showed that RBP and RBPNs can significantly improve the interfacial properties of NaCas by enhancing the interfacial interaction and the interfacial viscoelastic modulus of composite proteins, which is conducive to the stability of the foam system. The outcome of the study provided a theoretical basis for RBP and RBPNs to partially replace NaCas in the processing of foamed food.

β-carotene (BC) has various biological activities, such as anticancer properties, contributing to the prevention of cardiovascular diseases, etc., while the poor solubility and low bioavailability limit its further development in the food industry. Therefore, how to effectively encapsulate this unstable substance has become a hot topic. Here, different concentrations of sodium caseinate and ι-carrageenan (NaCas-CA) complex emulsions were used as wall materials, and the effect of spray-drying (SD) and vacuum freeze-drying (VFD) on the properties of BC powders loaded with NaCas-CA was investigated. The results showed that the characteristic peaks of BC disappeared in all powdered oils, indicating that BC could be effectively encapsulated. As the wall concentration increased, the surface oil of the powders decreased significantly. At the same concentration, the surface oil content of SD (minimum of 8.34%) was lower than that of VFD (minimum of 10.02%). However, the particle size of SD-reconstituted emulsions was larger than that of VFD. Furthermore, the SD-reconstituted emulsions were more stable than the VFD after storage at 25 °C for 3 h. This study reveals the effect of different drying methods on the structure and stability of powdered oils, providing valuable information for the research of functional active-loaded powdered oils and applications in the food industry.

In this paper, peanut protein (PP) was used as the sole raw material for the preparation of fluorescent carbon dots (PP-CDs) by hydrothermal method. The PP-CDs exhibit good dispersibility, spherical-like shapes, and uniform sizes; the average particle size of the PP-CDs was 3.18 ± 0.17 nm. The Fourier transform infrared spectroscopy (FTIR) results show that the surface of PP-CDs is rich in hydrophilic groups such as hydroxyl, carboxyl and amide groups. The PP-CDs exhibit good fluorescence emission properties and excitation wavelength dependence, with the optimal excitation wavelength and emission wavelength at 348 nm and 452 nm, respectively. According to the fluorescence quenching effect of metronidazole (MTZ) and tinidazole (TDZ) on PP-CDs, a highly linear fluorescence sensor was established, with a concentration range of 0.10–60.0 µM, and the detection limits of MTZ and TDZ are 32.0 nM and 48.0 nM, respectively. The result of CCK-8 test and imaging of HepG-2 cells and onion epidermal cells reveal that PP-CDs have good membrane permeability, biocompatibility and imaging ability.