36G-8 |
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G.-S. DO1, M. Tsuta2, S. Ueno3, J. Sugiyama4, and Y. Sagara3. (1) College of Bioresource Sciences, Nihon Univ., 1866 Kameino, Fujisawa-shi, Kanagawa, 252-8510, Japan, (2) Graduate School of Agricultural and Life Sciences, The Univ. of Tokyo, Tokyo, 113-8657, Japan, (3) Graduate School of Agricultural and Life Sciences, The Univ. of Tokyo, 1-1-1Yayoi Bunkyo-ku, Tokyo, 113-8657, Japan, (4) National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki, 305-8657 The ice crystals formed in frozen materials induce morphological changes, destruction of cells, and component degeneration, which may result in textural change and dripping after thawing. An understanding of the growth mechanism of ice crystals led to development of the optimum freezing method and improvement of the quality of frozen foods. The development of a method measuring for ice crystals is required to obtain the 3-D information on the morphology, size, and distribution. The objectives of this work were (1) to develop the Micro Slicer Spectral Imaging System (MSSIS) having functions to reconstruct the 3-D image obtained by cross-sectional images exposed after slicing the sample surface, and to obtain a spectroscopic image by near-infrared spectroscopy; and (2) to investigate the morphology and size of ice crystals in 1.0% w.b. agar dilute solution frozen one-dimentionally at |15C. MSSIS is composed of a micro-slicer, near-infrared (NIR) illuminator and spectral imaging system. According to the results of NIR spectroscopic analysis using MSSIS, a water absorption band around 965nm could be observed as well as an ice absorption band around 1025nm. Spectroscopic images of a frozen agar gel scanned at 1025nm showed the ice crystals could be clearly distinguished from the other components based on the difference of absorption coefficients. The average area of ice crystals was found to be 6,253m2, while the average distances of major and minor axes were 111 and 62m, respectively. Additionally, the reconstructed 3-D image of the ice crystals revealed that they were formed along with the direction of heat transfer. The proposed method has provided a novel tool to investigate the effects of freezing conditions on geometrical parameters of ice crystals.
Session 36G, Refrigerated & Frozen Foods: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |