Food Structure


Scanning electron microscopy (SEM) was used to study microstructural differences among five adzuki bean cultivars: Erimo, Express, Hatsune, Takara and VBSC. Seed coat surfaces showed different patterns of cracks, pits and deposits . Cross-sections of the seed coats revealed well organized layers of elongated palisade cells followed by many layers of amorphous parenchyma cells. Typical sub-epidermal layers of organized columnar, hour-glass cells were characteristica11y absent in the five cultivars of adzuki beans. The cross-sections of the cotyledons revealed intercellular materials between storage cells. Storage cells in Hatsune cultivar were loosely packed with many intercellular spaces as compared to the other four cultivars. Cross-sections of storage cells revealed starch granules embedded in protein matrices. The protein matrix appeared more granular in cultivars Erimo and VBSC and less granular in cuhivars Express, Hatsune and Takara. Flours of the five cultivars were examined under SEM to photograph individual starch granules and protein matrices. Starch granule shape was characteristic to each cultivar: spherical in Erimo cultivar, spherical to irregular in Express and Hatsune cultivars, highly irregular to slightly spherical or oval in Takara cultivar, and oval to spherical in VBSC cultivar. No grooves or fissures were observed in Erimo or VBSC starch granules. Shallow grooves were observed on the starch granules of Express and Hatsune cultivars. A characteri stic deep fissure was observed in starch granules of the Takara cultivar. The characteristic deep fissure on starch granules may be used as an identifying feature for Takara cultivar.

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