Texture Measurement of Radish(Daikon)and Effect of Freeze-Thawing Process

Effect of Freezing Process on the Texture of Vegetables Part V

Abstract

Mechanical properties of radish and their changes caused by freeze-thawing were measured by the method in the previous report. Little deviations of the texture to the directions of both cross section and longitude in the same individual of fresh radish were observed except narrow cambium and phloem zones in the surface layer. Blanching in boiling water was more suitable for the texture of radish than by steaming. Blanching time increased in proportion to the volume of the specimen, not to the shape. The increase of blanching time brought forth a marked softening to the large specimen which is eaten as cooked food in Japan. Air blast freezing and thawing in boiling water of the specimen reduced its firmness by about 50%, but this decrease is small as compared to the decrease in the case of carrot. It appears that the texture of radish is endurable to the treatment of freeze-thawing, but not resistant to heating. Dielectric thawing with a 2450MHz microwave oven was found to be not so much effective as expected for the improvement of the texture of the frozen radish specimen compared to thawing in boiling water. The former is not always an effective method for frozen vegetables because of difficulties of temperature control of the specimen.