Optimizing the parameters for compressive resistances of fresh eggs using cold chain logistics

A fairly high breakage rate can often occur in the cold-chain logistics of fresh eggs. In this study, the compression and freshness detection were designed for fresh eggs, with the storage temperature of the eggs and the coating material on the surface as the main parameters, and the storage time as the boundary conditions. The results demonstrated that the temperature of 2-8 ℃ retarded the rottenness of eggs for better pressure resistance. Whether at room temperature or low temperature, the relative elastic deformation with time was maintained at a high value. There was a small variation in the type of coating agent. The rottenness of eggs after coating was decelerated at room temperature. While the pressure resistance of eggs was improved to compromise at 2-8 ℃. Both the coating agent and the low temperature were superimposed to slow down the decrease of its freshness. A professional experimental group was organized to conduct the sensory scoring on different groups of eggs under various storage times. The Huff unit value and sensory scoring were similar to each other. Therefore, the freshness of fresh eggs decreased with the extension of storage time. After 14 days of storage, a small amount of egg contents were solidified in the non-coated group of eggs stored at 2 ℃. The sensory scores of the group were lower during that time period. A comprehensive evaluation model was established for the parameters of the cold-chain transportation using the analytic hierarchy process, particularly with the ultimate load, the relative elastic deformation, the Haugh unit value, and the sensory score of eggs as the decision-making indicators. The relative importance of each index was ranked to determine the importance discrimination matrix. The weights were calculated corresponding to each decision index, thus reflecting the importance of the decision index to the final. Four decision indicators were ranked in descending order of the Hough unit value, sensory score, ultimate load, and relative elastic deformation, according to the priority. The optimal parameters were achieved in the cold-chain logistics temperature and the coating material for different transportation durations as follows. In the cold-chain logistics duration of 0-4 days, the transportation temperature was at 2 ℃ with no paints applied; In the duration of 4-7 days, the transportation temperature was 5 ℃, with the chitosan solution chosen as the paints. In the duration of 7-10 days, the transportation temperature was selected at 2℃ with the polyvinyl alcohol solution chosen as the paint. For the duration of 10 to 14 days, the transportation temperature was 5 ℃ with no paints applied. The quality of stored eggs was generally better at low temperatures than that at room temperature. The coated eggs at room temperature were generally better than the uncoated eggs. While the coated eggs at low temperature were less than the uncoated eggs. The coating layer protected the eggs to reduce the damage from the external physical collisions in the cold-chain logistics of a short or medium distance, indicating the less rottenness of eggs. However, the coating layer on the eggs failed to protect them in the process of long-term cold-chain transportation. The coating layer deteriorated and even fell off in the low-temperature environment for a long time, leading to less pressure resistance and maintenance of the egg quality. The findings can provide theoretical support for the cold-chain logistics of fresh eggs.