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This study aimed to investigate how microwave vacuum drying (MVD) affects the drying kinetics, quality profiles, and microstructure of pork chip snacks (PCS). Fresh pork longissimus lumborum was sliced and dried under different power densities (4, 6, and 8 W/g) in a microwave vacuum oven. Five classical thin-layer drying models were used to evaluate the nonlinear fitting of the experimental data. The results indicated that the Midilli et al. model was the optimal model for describing the drying kinetics of PCS. Moreover, as the temperature increased during MVD, the surface of PCS gradually browned. Meanwhile, temperatures of 130.2 °C and 139.9 °C were critical for preventing severe browning and scorching of PCS. Furthermore, power densities induced accelerated drying of PCS, which led to microstructural damage and the formation of a porous structure. However, higher power density led to more pronounced drying non-uniformity of PCS, as well as severe lipid oxidation (P < 0.05), which notably altered the flavor of PCS. In summary, employing 4 W/g for 22 min in MVD emerged as the optimal parameter for PCS preparation. This study provides a novel strategy for the application of MVD in the processing of meat snacks. • Power density affects the drying time and quality profiles of pork chip snacks (PCS). • Midilli et al. model is the most suitable for describing the drying kinetics of PCS. • Brittleness and color-related properties are related to moisture diffusion. • PCS obtained by MVD at 4 W/g for 22 min exhibited high quality attributes. [ABSTRACT FROM AUTHOR]

The molecular interactions and mechanisms between four ethyl esters (ethyl acetate, ethyl butyrate, ethyl hexanoate, and ethyl octanoate) and myofibrillar proteins (MPs) were investigated. The gas chromatography and mass spectrometry results showed that binding capability was significantly enhanced as MP concentrations increased (p < 0.05). The four esters bound to MPs (6 mg/mL) with: ethyl octanoate > ethyl hexanoate > ethyl butanoate > ethyl acetate (p < 0.05), according to their binding capabilities. Moreover, hydrogen bonding was the dominant reversible physicochemical force between the MPs and ethyl esters. In addition, ethyl octanoate was the best MP fluorescence quenchera, and the static quenching performed a more predominant role in the fluorescence quenching process. Furthermore, the MPs' α-helix content gradually decreased as the concentration of ethyl octanoate was increased. Finally, the molecular docking and dynamic simulation verified that hydrogen bonding and van der Waals forces were the primary driving forces in the myosin-ethyl octanoate complex. This study sheds light on the interactions between proteins and ester compounds facilitating flavor regulation in protein-rich foods. • Myofibrillar protein (MP) concentrations affected MPs-ester binding capabilities. • Ester characteristics affected MPs-ester binding capabilities. • MPs-ethyl octanoate binding resulted in static fluorescence quenching. • Conformation of MPs was changed by interactions with ethyl octanoate. • Hydrogen bonding and Van der Waals forces were the main reversible interaction. [ABSTRACT FROM AUTHOR]

In this study, comprehensive lipid composition in the muscle tissue of four popularly consumed shrimp species was determined using ultra-performance liquid chromatography-triple time-of-flight tandem mass spectrometry (UPLC−Triple TOF−MS/MS). About 600 molecules from 14 types of lipids were characterized and quantified. Phospholipids (PLs) were the main component in all four shrimp species (51.4–71.0% of total lipids). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were the major PL subclasses (49.3–53.2% and 42.3–48.4% of total PLs). Triacylglycerol (TAG) and diacylglycerol (DAG) contents were relatively low (8.6–32.5% and 11.5–14.1% of total lipids). Docosahexaenoic acid (DHA, 22:6n-3), eicosapentaenoic acid (EPA, 20:5n-3) and arachidonic acid (AA, 20:4n-6) were dominant in free fatty acids (76.5–85.2%) and PL. Sphingolipid (SL) was detected in low content (<5% of total lipids). Using high throughput analytical method, detailed lipid composition in shrimp muscle were obtained, which could help to assess shrimp nutrition value and identify their species. • A UPLC-Triple TOF-MS/MS method was used to analyze the lipid composition of shrimp. • About 600 lipid compounds from 14 classes were identified. • Phospholipids were the main lipid in all 4 shrimp species. • Alkenyl-phospholipids and alkyl-phospholipids were detected and compared. [ABSTRACT FROM AUTHOR]

Addition of different (−)-epigallocatechin-3-gallate (EGCG) (0, 100, 200, 500 or 1000 mg/L emulsion) on the interfacial composition and protein-lipid co-oxidation of whey protein isolate (WPI)-stabilised oil-in-water (O/W) emulsions were studied, and underlying mechanisms were also explored. The results indicated that the physical stability of emulsions gradually decreased with the increasing level of EGCG during storage, which clearly verified by decreasing ζ-potential absolute values and increasing droplet size. Moreover, the combination between WPI and EGCG by covalent/non-covalent binding for either adsorbed proteins (AP) or unadsorbed proteins (UAP) led to aggregation and conformational changes in WPI, which confirmed and characterised by electrophoresis, fluorescence quenching, and molecular docking simulation. Meanwhile, the concentration of AP slightly decreased as a function of EGCG level and storage time, however, the UAP showed the opposite change tendency, indicating that EGCG could effectively modulate the interfacial adsorption property of WPI in O/W emulsions. In addition, the incorporation of EGCG efficiently suppressed protein-lipid co-oxidation of O/W emulsions during storage, which was illustrated by hierarchical cluster and correlation analysis between protein and lipid oxidation products. Our results clearly revealed the viability of the EGCG to modulate the interfacial composition and retard the co-oxidation of O/W emulsions with enhanced storability. • Higher levels of EGCG decreased the physical stability of O/W emulsions. • EGCG can alter the structure and molecular mass of whey protein isolate (WPI). • EGCG can bind to WPI mainly via hydrogen bonding and hydrophobic interactions. • EGCG could modulate the interfacial adsorption properties of WPI in O/W emulsions. • Incorporation of EGCG suppressed the protein-lipid co-oxidation of O/W emulsions. [ABSTRACT FROM AUTHOR]

The traditional dry sausage is highly appreciated in China because of its unique quality characteristics, but it contains high salt content. Hence, this study aimed to evaluate the effects of lactic acid bacteria (LAB) comprising Lactobacillus sakei (LS), Lactobacillus curvatus (LC), Lactobacillus plantarum (LP), and Weissella hellenica (WH) on the quality attributes of the reduced-salt dry fermented sausages. The results indicated that the LP sausage showed higher (P < 0.05) shear force value compared to the other sausages, while the LP, LC, and WH sausages had higher (P < 0.05) lightness values than the control sausages. Seventy-six volatile compounds were detected, and nine compounds were identified as the key differential volatile compounds among the sausages based on partial least squares discriminant analysis. Clustering analysis of electronic nose results corresponded well to the volatile compound results. The sensory evaluation confirmed that the inoculation with LC and LP had a positive impact on the aroma, color, and hardness attributes of the reduced-salt sausages. Besides, partial least squares regression analysis further indicated that L. curvatus and L. plantarum could be used as the potential starter cultures to manufacture reduced-salt dry fermented sausage having improved texture, color, and flavor. [Display omitted] • The LP sausage shows higher shear force value compared to the other sausages. • The LP, LC, and WH sausages have higher lightness values than the control sausages. • Seventy-six volatile compounds are detected in dry fermented sausage. • Sensory attributes correlate with the key volatile compounds using PLSR analysis. • L. curvatus and L. plantarum can improve the quality of reduced-salt dry sausage. [ABSTRACT FROM AUTHOR]