To prevent the loss of eggs used for consumption, it is important to know the individual shelf life of eggs. In this study, a method for the estimation of the individual shelf life of eggs was proposed, based on the diffuse reflectance spectra mapping data obtained from the egg surface. The storage test for the eggs was conducted at a constant temperature, and for the test period, the spectra at 16 points on the surface of each egg, its Haugh Unit (HU) values, and albumen ATP values were measured every 3 days. The HU values were found to be highly correlated to the number of days after laying (DAL) with R2=0957. The relationships between the spectra mapping data and DAL were analyzed using the PLSR method, and ten wavelengths with good correlation performance were nominated. An estimation model for HU and albumen ATP values of eggs based on the spectra and its secondary different data was then constructed using neural networks with 20 input layer neurons, 40 hidden layer neurons, and 2 output layer neurons. The results obtained using the trained neural network estimation model showed good agreement with the measured data, the performance being ±5.5% in average relative error both for HU values and ATP values.
The vacuum drying method was applied to the drying of adzuki beans in this study. The effects of vacuum level and temperature on the drying rate and sample quality (intact bean kernel and hull) of adzuki beans were examined at various temperatures (20～70℃) and vacuum pressure levels (0.07～0.10 MPa). Broken and cracking sample beans were not observed under any measurement conditions. The drying rate of the sample was faster with vacuum drying than with hot air drying. The vacuum drying method was found to be applicable to adzuki beans with a moisture content of 25% on a dry basis or less at temperatures of 20～70℃. A new drying model related to temperature and vacuum level was developed to estimate changes in the moisture content of adzuki beans during vacuum drying with sufficient accuracy for practical use. The effective diffusion coefficients of the sample were estimated using Fick's second diffusion model, and they were shown to be a function of temperature and vacuum level.
Asparagus spears continue to grow even after harvest, but their quality may deteriorate over time. Therefore, methods for maintaining freshness are needed to ensure the quality and function of harvested asparagus spears. In this study, we examined the changes in the external appearance, Brix levels, moisture content, and hardness of sixth-year spears of 'Zenyu Yodel (NJ953)' for spring harvest under varying conditions of transportation and storage, including their orientation during storage. Asparagus spears transported and stored at low (chilling) temperatures showed better quality characteristics than those transported and stored under non-chilling conditions. Furthermore, the quality of spears stored vertically in water was better than that of spears stored horizontally. Moreover, in the asparagus spears transported at low temperature, Brix levels were lower in spears stored in water than in those stored without water. Wilting was also not observed in the spears stored in water. These results suggest that transportation conditions, storage temperature, and orientation of the asparagus spears during storage influence their quality.