Changes in water holding capacity of chilled fresh pork in controlled freezing-point storage assisted by different modes of electrostatic field action

Mitigating quality deterioration in chilled pork by combining cinnamaldehyde nanoemulsions and a high-voltage electrostatic field

Cinnamaldehyde nanoemulsion (CNE) was obtained through ultrasonication, using Tween 80 as an emulsifier. The CNE was then applied to chilled pork in conjunction with a high-voltage electrostatic field (HVEF) to mitigate quality deterioration during refrigerated storage. The particle size of CNE ranged from 60 to 150 nm and was positively correlated with the amount of added cinnamaldehyde. The polydispersity index and zeta potential of CNE ranged from 0.25 to 0.30 and - 12 to -11 mV, respectively, indicating a narrow size distribution and stability. The CNE released the odor specific to cinnamaldehyde to pork in the first 4 days of chilling; however, it had little effect on the taste. HVEF pretreatment reduced the initial total viable count (TVC) in pork by 1.14 log cycle. The combination of CNE with HVEF successfully slowed down the loss of moisture, decrease in pH, and accumulation of total volatile basic nitrogen in pork during refrigeration. Furthermore, it mitigated the increase in TVC of pork. Therefore, this integrated method appears to be suitable for extending the shelf life of chilled pork.

Polysaccharide- and protein-based edible films combined with microwave technology for meat preservation

To reduce food-borne bacterial infection caused by food spoilage, developing highly efficient food packing film is still an urgent need for food preservation. Herein, microwave-assisted antibacterial nanocomposite films CaO2@PVP/EA/CMC-Na (CP/EC) were synthesized using waste eggshell as precursor, egg albumen (EA) and sodium carboxymethylcellulose (CMCNa) as matrix by casting method. The size of CaO2@PVP (CP) nanoparticles with monodisperse spherical structures was 100-240 nm. When microwave and CP nanoparticles (0.05 mg/mL) were treated for 5 min, the mortality of E. coli and S. aureus could reach >97 %. Under microwave irradiation (6 min), the bactericidal rate of 2.5 % CP/EC film against E. coli and S. aureus reached 98.6 % and 97.2 %, respectively. After adding CP nanoparticles, the highest tensile strength (TS) and elongation at break (EB) of CP/EC film reached 19.59 MPa and 583.43 %, respectively. At 18 °C, the proliferation of bacterial colonies on meat can be significantly inhibited by 2.5 % CP/EC film. Detailed characterization showed that the excellent meat preservation activity was due to the synergistic effect of dynamic effect generated by ROS and thermal effect of microwave. This study provides a promising approach for the packaging application of polysaccharide- and protein-based biomass nanocomposite antibacterial edible films.

Effects of different electrostatic field intensities assisted controlled freezing point storage on water holding capacity of fresh meat during the early postmortem period

In this study, the effect of different intensity electrostatic fields on the water holding capacity (WHC) of fresh meat during the early postmortem period in controlled freezing point storage (CFPS) were investigated. Significantly lower cooking loss were found in low voltage electrostatic field (LVEF) and high voltage electrostatic field (HVEF) compared to the control group (CK) (p < 0.05). The myofibril fragmentation index and microstructure results suggested that the sample under HVEF treatment remained relatively intact. It has been revealed that the changes in actomyosin properties under electrostatic field treatment groups were due to the combination and dissociation of actomyosin binding into myofilament concentration, which consequently affects the muscle WHC. The study further demonstrated that the electrostatic field, especially HVEF, might increase the WHC of fresh meat by affecting the distribution of water molecules and physiochemical properties of actomyosin during the early postmortem period.

Improving the Edible and Nutritional Quality of Roasted Duck Breasts through Variable Pressure Salting: Implications for Protein Anabolism and Digestion in Rats

Variable pressure salting (VPS) is considered a novel salting approach to improve meat quality. This study aimed to investigate the effects of roasted duck's edible and nutritional quality after VPS through serum biochemical indicators and in vivo digestion properties in rats. The results show that roasted duck after VPS led to an increase in the total protein content (57.24 g/L) and blood glucose levels (6.87 mmol/L), as well as a decrease in the blood urea nitrogen content (11.81 mmol/L), in rats. Compared to rats fed base diets and roasted duck after static wet salting (SWS), those ingesting roasted duck after VPS exhibited higher values of apparent protein digestibility (51.24%), pepsin activity (2.40 U/mg), and trypsin activity (389.80 U/mg). Furthermore, VPS treatment improved the textural properties and microstructure of duck breasts shown by a higher immobilized water relaxation area and more ordered protein structures (α-helixes and β-sheets). These improvements enhanced the protein anabolism capacity and in vivo digestion properties in rats. Therefore, VPS represents a beneficial salting method for promoting effective digestion and absorption in rats.

LF-NMR determination of water distribution and its relationship with protein- related properties of yak and cattle during postmortem aging

The water distribution have a profound influence on meat quality, and proteins play a critical role in water distribution. The water distribution detected with proton NMR and its relationship with protein related properties were investigated. Three populations of water were detected: bound water (T21, P21), immobilized water (T22, P22), and free water (T23, P23). The decreased T22 and T23 indicated an increase in water-holding capacity in both muscles from 3 days of aging. The P22 in cattle was higher than that in yak and the P23 in cattle was lower than that in yak, suggesting that cattle exhibited a greater water-holding capacity compared to yak. Moreover, postmortem aging affected muscle protein oxidation, denaturation, and degradation. Correlation analysis suggested that protein oxidation and denaturation caused muscle water loss and protein degradation could allow the muscle to retain water. It provides a basis for the optimization of quality of meat and products.