This study investigated the influence of flaxseed oil addition on high-moisture textured vegetable proteins (TVPs) made of soy protein isolate (SPI) and wheat gluten. The effects of oil form (non-emulsified vs. emulsified) and emulsifier type on structure, oxidation stability and digestion were evaluated. Three TVPs were prepared by adding emulsions stabilised with SPI, octenyl succinic anhydride-modified starch and lecithin during extrusion. These samples were named TVP-E-SPI, TVP-E-OSA starch and TVP-E-Lecithin, respectively. Two controls, TVP-Bulk oil and TVP-N, were prepared with added bulk oil and without added oil, respectively. Oil/emulsion addition reduced fibrous layer separation and hardness, increased porosity and enhanced protein secondary structure order. Compared with bulk oil addition, emulsion addition promoted finer filamentous fibre formation with less influence on texture and higher protein secondary structure order. The oxidation stability of emulsion-added TVPs depended on emulsifier type. TVP-E-SPI showed oxidation stability comparable to TVP-Bulk oil, whereas TVP-E-OSA starch showed increased secondary oxidation and TVP-E-Lecithin exhibited increased primary and secondary oxidation. Among emulsion-added TVPs, TVP-E-SPI displayed the most abundant filamentous fibres and highest fibre density, suggesting the strongest oil droplet-matrix interaction. Hardness, chewiness, protein secondary structure order and oxidation stability generally followed the trend: TVP-E-SPI > TVP-E-OSA starch > TVP-E-Lecithin, positively correlating with interaction strength. In vitro digestion demonstrated that the addition of bulk oil or emulsions improved protein digestibility. Emulsion-added TVPs exhibited higher protein digestibility and oil bioaccessibility than TVP-Bulk oil. However, emulsifier type did not significantly affect protein digestion or oil bioaccessibility, likely due to the low emulsion addition level.
Many natural food proteins with desirable functional properties are limited by poor water dispersibility, which restricts their practical application. In this study, egg yolk granules (EYG) and zein, two intrinsically water-insoluble proteins with distinct origins of insolubility, were used to construct soluble protein complexes through a simple pH-driven co-assembly process. Stable EYG-Zein complexes were obtained within a defined compositional range, and the optimal mass ratio of 2:3 showed the smallest hydrodynamic diameter and the highest colloidal stability. Multiscale characterization indicated that the mutual solubilization of EYG and zein was governed primarily by non-covalent interactions and accompanied by structural reconstruction. Fluorescence quenching and thermodynamic analysis further suggested that hydrophobic interactions were the dominant driving force for complex formation. Compared with dissociated EYG, the EYG-Zein complexes exhibited higher surface hydrophobicity and showed enhanced ice recrystallization inhibition activity, which became stronger with an increasing proportion of zein. In an ice cream system, incorporation of EYG-Zein effectively suppressed ice crystal growth while causing minor changes in color and no significant adverse effects on melting behavior, texture, or aroma-related properties. These results demonstrate that pH-driven all-protein co-assembly can serve as an effective strategy for converting EYG and zein into functional colloidal complexes and highlight the potential of EYG-Zein complexes as antifreeze ingredients in frozen foods.
Amyloid fibrils hold potential in food delivery systems, yet their network architecture is susceptible to disruption from the isoelectric point to extreme alkaline conditions. This study investigated the morphological transitions and functional properties of whey protein isolate fibrils (WPIF) complexed with kappa-carrageenan (KC) across a broad pH range (5.0-12.0). Molecular docking, spectroscopy, and microscopic imaging confirmed that KC was non-covalently coated onto the WPIF surface, primarily driven by electrostatic interactions and hydrogen bonding. This steric hindrance suppressed fibril aggregation near the isoelectric point (pH 5.0) and attenuated depolymerization under highly alkaline conditions (pH 12.0). Consequently, the KC-WPIF complexes preserved a rigid, beta-sheet-rich backbone and exhibited enhanced weak-gel rheological properties. When utilized as an emulsifier for beta-carotene (BC)-loaded emulsions, the complex demonstrated optimal interfacial activity and emulsion stability under mildly alkaline conditions. Specifically, formulations at pH 8.0 displayed excellent environmental tolerance, with retention rates of >95% and >85% of BC after ultraviolet irradiation and thermal treatment, respectively, alongside a 79.8% DPPH scavenging rate. Furthermore, in vitro assays revealed that the composite system promoted lipid hydrolysis, elevating BC bioaccessibility to 69.3%. These findings highlight the potential of polysaccharide coatings to overcome the inherent pH sensitivity of protein amyloid fibrils, furnishing a theoretical framework for engineering highly stable, food-grade colloidal delivery systems across a broad pH range.
Postharvest blueberries are highly susceptible to Alternaria alternata (A. alternata) and Fusarium fujikuroi (F. fujikuroi) infections, which induce decay and produce abscisic acid (ABA). This study investigated how exogenous ABA influenced blueberry ferroptosis during fungal pathogenesis. Results showed that ABA treatment was associated with accelerated lesion expansion, with ABA accumulation in adjacent areas but depletion in lesion areas of infected fruit. ABA treatment correlated with chlorophyll degradation in thylakoid membranes and elevated hydrogen peroxide (H2O2), malondialdehyde (MDA), and ferrous ions (Fe2 +) in both areas, while reducing glutathione (GSH) levels. Correlation analysis revealed that ABA primarily modulated the ROS-lipid peroxidation axis rather than iron homeostasis. Notably, ABA treatment was correlated with increased saturated fatty acids and altered fatty acid unsaturation indices, with distinct effects on oxylipins (OAHFAs) and phospholipids (MLCL, PG and PC). ABA treatment was also associated with mitochondrial stress and dysfunction, and exacerbated plasmalemma PC peroxidation in lesion areas, correlating with accelerated decay. These findings suggested that ABA might act as a virulence factor by amplifying ROS-driven ferroptosis, yet exhibit dual roles in modulating membrane lipid dynamics. This research highlighted ABA as a potential therapeutic target for mitigating postharvest blueberry decay.
We propose here a novel bivariate gamma degradation model to characterize products that have multiple correlated performance characteristics (PCs). The proposed model is asymmetric and capable of capturing a strongly structured physical dependence between the two PCs. Several statistical properties of the model are obtained, and the reliability function and the remaining useful life (RUL) distribution are derived. The penalized likelihood approach is utilized to derive the maximum likelihood estimators for the model parameters and the reliability function. The generalized confidence intervals for these quantities are then constructed using the generalized pivotal quantity method, as well as the generalized prediction intervals for the RUL. In addition, bootstrap-p methods are adopted to construct both confidence intervals and prediction intervals. The performance of the proposed estimation methods is evaluated through Monte Carlo simulations. Finally, the polymeric coating data set is analyzed to demonstrate the applicability and usefulness of the proposed framework.
