TECHNOLOGY OF CEREALS FG3.7 electon micrograph of one large starch granule and numerous small starch granules arge granule shows the equatorial groove. From A D. Evers, Starke, 1971, 23: 15 Reproduced with permission of the Editor of Die Starke. an experienced microscopist can identify the cereals are similar in shape to the smaller popula source, either from observation of an aqueous tion of Triticeae granules, but rice and oats have suspension at room temperature or with the some compound granules in which many granuli additional help of observed changes when the fit together to produce large ovoid wholes. Shapes suspension is heated, leading to gelatinization at of high-amylose granules are varied and may be a temperature characteristic of the species and related to their individual composition. The later type (snyder, 1984). The characteristic blue developers tend to be filamentous, some resembling staining reaction with iodine/potassium iodide strings of beads. Characteristics of starch granules solution does not occur with waxy granules, from cereals are shown in Table 3.4 which contain virtually no amylose, they stain Within the endosperm of a species small differ brownish red to yellow. It is characteristic ences in granule shape may arise as a result for amylose percentage to increase during of packing conditions. These can be seen in endosperm development, consequently staining grains as mealy and vitreous(or horny)regions reactions change during growth In mealy regions, packing is loose and Granules of cereals from the Triticeae tribe(see adopt what appears to be their natural form. In Ch. 2)are of two distinct types. The larger ones horny regions close packing causes granules to are biconvex while the smaller ones are nearly become multi-faceted as a result of mutual pres spherical (Fig. 3.7). Granules from most other sure. Small indentations can also arise from other58 TECHNOLOGY OF CEREALS FIG 3.7 Scanning electon micrograph of one large starch granule and numerous small starch granules of wheat. The large granule shows the equatorial groove. From A.D. Evers, Stiirke, 1971, 23: 157. Copyright by Leica U.K., Reproduced with permission of the Editor of Die Stiirke. cereals are similar in shape to the smaller popula￾tion of Triticeae granules, but rice and oats have some compound granules in which many granuli fit together to produce large ovoid wholes. Shapes of high-amylose granules are varied and may be related to their individual composition. The later developers tend to be filamentous, some resembling strings of beads. Characteristics of starch granules from cereals are shown in Table 3.4. Within the endosperm of a species small differ￾ences in granule shape may arise as a result of packing conditions. These can be seen in grains as mealy and vitreous (or horny) regions. In mealy regions, packing is loose and granules adopt what appears to be their natural form. In horny regions close packing causes granules to become multi-faceted as a result of mutual pres￾sure. Small indentations can also arise from other an experienced microscopist can identify the source, either from observation of an aqueous suspension at room temperature or with the additional help of observed changes when the suspension is heated, leading to gelatinization at a temperature characteristic of the species and type (Snyder, 1984). The characteristic blue staining reaction with iodine/potassium iodide solution does not occur with waxy granules, which contain virtually 'no amylose, they stain brownish red to yellow. It is characteristic for amylose percentage to increase during endosperm development, consequently staining reactions change during growth. Granules of cereals from the Triticeae tribe (see Ch. 2) are of two distinct types. The larger ones are biconvex while the smaller ones are nearly spherical (Fig. 3.7). Granules from most other