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The solubility of oxygen and its transfer rate to the lipid phase play important roles in lipid oxidation, which affects the taste and safety of lipid-containing foods. In this study, we measured the Henry's constants (solubility) of oxygen for fatty acids, fatty acid esters, and triacylglycerols (TAGs; vegetable oils), as well as the mass transfer coefficients of oxygen at the gas- and water-lipid interfaces. The constants and coefficients were estimated by analyzing the change over time in the oxygen partial pressure or concentration in the closed container based on the mass balance equations of oxygen in the gas and liquid phases. The constant for water obtained by the method used in this study was in agreement with the previously reported value to confirm the validity of the method. The constants for lipids depended on the lipid type, and were higher in the order of fatty acid ester, fatty acid, and TAG. That is, the solubility of oxygen decreased in this order. For all lipids, the constant increased as the number of carbon atoms in the fatty acid chain increased. The constants for fatty acids and their esters were linearly correlated with the enthalpies of evaporation of the lipids. The mass transfer coefficients of oxygen at the gas-liquid interface were on the order of 10-5 m/s for water and methyl dodecanoate and of 10-6 m/s for TAG (rapeseed oil). The coefficient at the water-lipid interface was on the order of 10-6 m/s. PRACTICAL APPLICATION: The Henry's constants (solubility) and transfer rate of oxygen to the lipid phase, fatty acids, fatty acid esters, and triacylglycerols (TAG) were measured. The lipids solubilized three to five times more oxygen than water, and mass transfer rate of oxygen at gas- and water-lipid interfaces were almost same. The constants for fatty acids and fatty acid esters were linearly correlated to their enthalpies of evaporation, and this correlation is expected to be useful for estimating the Henry's constants for other fatty acids and their esters.

The shrinkage of sheet-like and cylindrical pastas of different moisture contents and distributions was measured. A slight anisotropy in shrinkage was observed for both the pastas. The shrinkage ratio of the height to the width directions for the sheet-like pasta slightly depended on the drying conditions and was 0.93 to 0.96. The shrinkage coefficient in the longitudinal direction scarcely depended on the moisture content and was 0.23 for the cylindrical pasta. Although the shrinkage coefficient in the diametric direction for both the pastas was 0.21 at moisture contents higher than 0.17, the coefficient increased for the moisture contents lower than 0.17. The Young's modulus of the dumbbell specimen of pasta did not depend on the drying conditions. However, it decreased with a decrease in the moisture content and became almost constant at the moisture contents lower than 0.17. These facts suggested that glass transition significantly affected mechanical properties of pasta.