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.

The present study focused on developing a rapid, efficient, and eco-friendly method for the analysis of perfluoroalkyl carboxylic acids (PFCAs) in aqueous matrices. The proposed method was based on esterification of PFCAs by isobutyl chloroformate followed by dispersive liquid-liquid microextraction (DLLME) of the derivatives. Quantitation of the isobutyl esters of PFCAs was carried out by gas chromatography-mass spectrometry with electron ionization. Under the optimal conditions, PFCAs could be determined in linear ranges of 1-1000 ng mL(-1) with good correlation coefficients (r > 0.991). The limits of detection and limits of quantification ranged from 0.9 - 3.0 ng mL(-1) and 2.7 - 9.0 ng mL(-1), respectively. The method showed satisfactory reproducibility with intra-day and inter-day relative standard deviations (RSDs) in the range of 3.4 - 14.6% and 3.5 - 17.2%, respectively. It was successfully applied to determine PFCAs in several river and lake waters, ranging from 8.47 to 150.14 ng mL(-1).

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, a sensitive method for the determination of 3-chloro-1,2-propanediol (3-MCPD) by high performance liquid chromatography-fluorescence detection (HPLC-FLD) was established, in which 9-(2-Hydroxypropyl) adenine (HP-Ade) was selected as the fluorescent derivatization reagent because of its good water solubility and hydrophobicity. The principle of the method lies in the origination of chloroacetaldehyde with the periodate oxidation of 3-MCPD and its' fluorescence derivatization by HP-Ade to produce a strong fluorescent substance, name as 1-N⁶-vinylidene-9-(2-hydroxypropyl)adenine (ε-HP-Ade), used for quantitative determination of 3-MCPD by HPLC-FLD. Some mobile phase conditions and incubation parameters related with the method features were studied and optimized. Under the optimal conditions, the method shows high sensitivity, good linearity (r² = 0.999) and good repeatability (RSD% between 1.04% and 2.55%), the detection limit (LOD) and quantification limit (LOQ) were 0.02 ng/mL and 0.06 ng/mL respectively. It has been successfully applied for the determination of various edible vegetable oil samples, the chromatogram shows symmetrical peak shape, perfect separation and very “clean” profiles. In comparison with gas chromatography-mass spectrum (GC-MS), the pretreatment process of the proposed method was totally operated in aqueous phase, the instrument requirements and cost are relatively lower, thus it will provide another choice for the routine analysis of 3-MCPD. Graphical Abstract

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.