It is thought that surface melting and puffing of freeze-dried amorphous materials are related to the difference between the surface temperature (T) and freeze-concentrated glass transition temperature (T') of the materials. Although T' is a material-specific parameter, T is affected by the type and amount of solute and freeze-drying conditions. Therefore, it will be practically useful for preventing surface melting and puffing if T can be calculated using only the minimum necessary parameters.
View Article and Find Full Text PDFWater-soluble carbohydrates commonly exist in an amorphous state in foods and undergo glass-rubber transition (glass transition) at the glass transition temperature (). The critical water content () and critical water activity () are the water content and water activity () at which the glass transition occurs at 298 K (typical ambient temperature), respectively. For amorphous water-soluble carbohydrates, can be predicted from the of anhydrous solid () using previously reported equations.
View Article and Find Full Text PDFThe purpose of the present study was to clarify the browning behavior of calcium maltobionate (CaMb). CaMb samples with varying water content (0-50 %) and water activity (0-0.98) were prepared.
View Article and Find Full Text PDFFresh-cut leafy vegetables are one of the most perishable products because they readily deteriorate in quality even during cold storage and have a relatively short shelf life. Since these products are in high demand, methods for rigorous quality control and estimation of freshness that are rapid and non-destructive would be highly desirable. The objective of the present research was to develop a rapid, non-destructive near-infrared spectroscopy (NIRS)-based method for the evaluation of changes during cold storage of lettuce using an aquaphotomics approach to monitor the water molecular structure in lettuce leaves.
View Article and Find Full Text PDFThe objective of this study was to use aquaphotomics and near-infrared (NIR) spectroscopy to follow the changes in strawberries during cold storage in the refrigerator with an electric field generator (supercooling fridge, SCF) and without it (control fridge, CF). The NIR spectra of strawberries stored in these refrigerators were collected over the course of 15 days using a portable mini spectrometer and their weight was measured daily. The spectral data in the region of the first overtone of water (1,300-1,600 nm) were analyzed using aquaphotomics multivariate analysis.
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