The Impact of Package Type and Temperature on the Changes in Quality and Fatty Acids Profile of Table Eggs during Their Storage

Assessing the structural and foaming property changes in egg yolk proteins due to malondialdehyde: Experimental and molecular docking studies

This study evaluated the effects of varying levels of malondialdehyde (MDA) on the structural and foaming properties of the egg yolk proteins (EYPs), and the interaction between them was explored by molecular docking. The results showed that oxidative modification due to MDA increased the carbonyl content of EYPs by 4.49 times. Simultaneously, the total sulfhydryl content was reduced by 21.47%, and the solubility of EYPs was significantly decreased (p < 0.05). Continuous oxidation disorders the previously ordered structure of EYPs. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that some proteins underwent crosslinking and aggregation with increased MDA oxidation, aligning with changes in particle size and zeta-potential. Moderate oxidation (<1 mmol/L) enhanced the foaming capacity and foam stability of EYPs. Additionally, molecular docking results uncovered favorable interactions between MDA and specific EYPs, primarily through hydrogen bonding. This research offers valuable insights into managing the functional and quality changes of yolk products during processing.

Untargeted Lipidomics Reveal Quality Changes in High-Moisture Japonica Brown Rice at Different Storage Temperatures

Low temperatures are an effective way of delaying grain rancidity and deterioration. However, little is known about the difference in quality changes in high-moisture japonica brown rice at different storage temperatures. In this study, the storage quality changes in japonica brown rice with a 15.50% moisture content stored at 15 °C, 20 °C, and 25 °C were investigated. In addition, an untargeted lipidomics analysis coupled with gas chromatography and mass spectrometry (GC-MS) was applied to analyze the volatile compounds and metabolite changes in the high-moisture japonica brown rice. The results showed that storage at 15 °C could well maintain the color and aroma stability of the brown rice and delay the increase in fatty acid value (FAV). The lipidomics results showed that storage at 15 °C delayed glycerolipid and sphingolipid metabolism and reduced glycerophospholipid catabolism in the brown rice. The low-temperature environment regulated these three metabolic pathways to maintain higher contents of triglycerides (TG), phosphatidylserine (PS), abd phosphatidylethanolamine (PE), and lower contents of diglycerides (DG), OAcyl-(gamma-hydroxy) FA (OAHFA), ceramides (Cer), and glycosylceramides (Hex1Cer) in the high-moisture japonica brown rice, which maintained the storage stability of the brown rice. Our results proposed the cryoprotection mechanism of postharvest brown rice from the perspective of volatile compounds and metabolite changes, providing a foothold for the further exploration of low-temperature storage as a safe and efficient cryoprotectant in the grain storage field.

Influence of Storage Packaging Type on the Microbiological and Sensory Quality of Free-Range Table Eggs

The studies aimed to assess the impact of packaging, storage time, and temperature on the microbiological quality as well as on the sensory quality and functional properties of chicken eggs. The study material consisted of eggs from laying hens kept under free-range conditions. The eggs packed in cardboard and plastic cartons were stored at 5 °C and 22 °C, respectively. The eggs were examined on the day of laying and on days 14 and 28 of storage. The microbiological quality of the shell and contents of the eggs and the foaming properties of the egg white stored in cardboard and plastic packaging as well as the sensory characteristics of the eggs stored in both types of packaging after hard-boiling were examined on all evaluation dates. The type of packaging in which the eggs were stored was shown to influence the microbiological quality of the egg contents. Eggs stored in plastic packaging, on days 14 and 28 of storage, contained more bacteria in egg contents than eggs stored in cardboard packaging (p < 0.05). The type of packaging in which the eggs were stored did not have an effect on the foaming properties of the egg white (p > 0.05) or on the sensory characteristics of the eggs after hard-boiling. Irrespective of the type of packaging, the foaming properties of the egg white and the sensory characteristics of the eggs after hard-boiling deteriorated with storage time. The effect of temperature on egg quality was found. Regardless of the type of packaging, eggs stored at 5 °C after hard-boiling had better yolk colour, smell, and texture than eggs stored at 22 °C (p < 0.05).

Supplemental methionine selenium effects on egg yolk physicochemical, functional, and protein structure during storage

To clarify the effect of the addition of methionine selenium on the physicochemical, functional, and protein structural properties of egg yolk during storage. We analyzed the changes in the main indicators of egg yolks stored at 4°C and 25°C for 28 days. The results showed that the increase in water content and pH, and the decrease in absolute zeta potential and apparent viscosity of the selenium-rich egg yolks (Se-group) during storage were smaller than those of the control group egg yolks (C-group). In addition, the antioxidant capacity and emulsifying ability of the Se-group during storage were better than those of the C-group. Simultaneously, the hardness and chewiness of the Se-group gel during storage were lower than those of the C-group. The protein structure results showed that selenium rich treatment did not affect the secondary structure of egg yolk protein during storage but could improve the fluorescence intensity of the egg yolk protein. Therefore, the addition of methionine selenium can reduce the degree of deterioration in the physicochemical properties of egg yolk during storage and extend its shelf life.