This study investigated the effects of vacuum packing on the semi-permeability of cell membranes and the effects of vacuum packing and subsequent cooking under a vacuum-packed condition on seasoning. Samples of Japanese radish were immersed in ₀.₅% NaCl solution either immediately after vacuum packing or after ₃ days of packing. There was no considerable increase in NaCl concentration in the Japanese radish, suggesting that vacuum packing had little or no effect on membrane semi-permeability.

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... asoning concentrations immediately after packing as well as after cooking were measured in Japanese radish samples that were vacuum packed in ₁.₅% or ₆% NaCl solution or in ₁₇.₅% sucrose solution. In the case of after packing, NaCl and sucrose concentrations were significantly higher in the vacuum-packed samples than in the non-vacuum-packed samples because NaCl or sucrose solution flowed into the vacuum-packed samples. However, in the case of after cooking, these concentrations were slightly higher in the vacuum-packed samples due to the loss of the semi-permeability of cell membranes followed by the diffusion of these components. In the case of ₆% NaCl solution, NaCl concentration of the cooking samples was appropriate in spite of a small amount of solution. This study suggested that in the case of after packing, seasoning concentrations were higher in the vacuum-packed samples because seasoning solution flowed into the samples due to the pressure gradient, and that seasoning concentrations of the cooked samples which were vacuum-packed in a small amount of seasoning solution with high solute concentration were appropriate.