1 0 0 0 OA 画像計測を利用した食品素材の弾性的特性値評価
クリープメータによる計測結果および市販のデジタルカメラで取得した画像を利用することで農産物・食品素材のヤング率およびポアソン比を計測した.画像計測は非接触のまま変形量の評価が可能であるため,煮熟された食品素材のように軟弱な試料であってもその変化を精密に解析することが可能であった.本手法を適用して,煮熟時間の経過に伴うダイコンおよびニンジンのポアソン比とヤング率の変化を計測したところ,ヤング率は沸騰水に投入直後から著しく低下するのに対し,ポアソン比の変化は緩慢であることが明らかとなった.またヤング率はダイコン,ニンジンともほぼ同様の値を示したが,ポアソン比はダイコンの方がニンジンよりも大きな値を示した.画像を利用した弾性的特性値の計測,評価法は,例えば食品素材の嚥下特性評価にも有効であると考えられる.
- 著者
- 松浦 元樹 田川 彰男 小川 幸春 Akio Tagawa 小川 幸春 Yukiharu Ogawa
- 出版者
- 千葉大学大学院園芸学研究科
- 雑誌
- 食と緑の科学 (ISSN:18808824)
- 巻号頁・発行日
- no.65, pp.55-59, 2011-03
Young's modulus and Poisson's ratio, which characterized elastic properties of a material, were measured bymeans of compress utensil and digital images captured by digital camera, and the elastic values were evaluated. Atissue of boiled Japanese radish and carrot root, which is too fragile to measure their Poisson's ratio by traditionalmethods, was used as sample materials. Cylindrical samples were cut out of the tissue using a precise apparatusand their dimensions were set to 15mm height and 30mm diameter. The samples were then compressed. The stressof the samples against compression was measured using a creep meter. The compressed deformation of the sampleswas captured by a digital camera and accurately analyzed by high resolution digital images. The Poisson's ratio wascalculated from differences in the sample deformation in digital images. A Young's modulus was also calculatedfrom the compressed deformation and the stress. As a result, the Poisson's ratio of boiled Japanese radish wasfound to be constant or slightly decrease with boiling elapsed time. The Poisson's ratio of carrot also decreasedwith boiling, and its value was smaller than the Japanese radish's. On the other hand, the Young's modulus for eachsample decreased sharply when boiling started but after 4 minutes boiling it was stabilized at low values.