Some chemical and physical properties of starch prepared from trunks of sotetsu (Cycas revoluta Thunb.) (sotetsu A) were compared with starches prepared from seeds of sotetsu (Sotetsu B) and ginkgo (Ginkgo biloba L.) seeds. The results obtained were as follows 1) The mean particle size of sotetsu A, sotetsu B and ginkgo starches were 13.2pm, 9.5 pm and 12.4 pm, respectively. 2) The susceptibility of sotetsu A starch granules to hog pancreatin was similar to that of sweet potato starch granules having relatively high susceptibility. By scanning electron microscopy (SEM), the appearance on the surface of sotetsu A starch granules attacked by pancreatin was quite similar to the case of normal maize starch granules, for which the enzymatic attack usually started with small pits on the surface of the granules and then the pits increased in number and in size during the subsequent enzyme attack. 3) The initiation temperature for gelatinization of sotetsu A starch, by photopastegraphy and differential scanning calorimetry (DSC) were 58.5 and 63. it, respectively. The enthalpy change, 4H, determined by DSC was 3.7 cal/g, which was relatively lower than that of the other two starches. The maximum viscosity and breakdown of sotetsu A, determined by Brabender's amylography (6%), were 460 BU and 30 BU, respectively. Breakdown was low like sotetsu B and ginkgo starches. 4) The amylose contents of sotetsu A starch, determined by amperometric titration and enzyme-chromatographic method, were 25.2, 23.2%, respectively. 5) Texture of 6% starch gels was determined by curdmeter and a Rheoner; sotetsu A formed gel having low hardness and breaking force and relatively high cohesiveness.

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Rice flour has been used as an ingredient for making dango, daihuku-mochi and rice crackers in Japan. The quality of these food products appeared to be directly affected by the flour used. However, not much has been known about the quality factors of rice flour. Accordingly, we investigated the properties of rice flour prepared by two different methods : dry-milling and wet-milling. The distribution of particle size of rice flours was affected by the type of the milling machine used. The forms of particles of the rice flour were different in dry-milling and wet-milling. The particles of rice flour from dry-milling were observed as fragments of rice grains. The wet-milled flour particles were observed as a cluster of starch granules. Dango made from the wet-milled flour tasted better and was slow in hardening. From these results, we concluded that the property of rice flour was affected basically by the size and form of particles of the flour provided its starch was not highly damaged.

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Some physicochemical properties of starch granules prepared from bulbs of Katakuri, which were collected in Akita Prefecture, were investigated. The average particle size of Katakuri starch was 24.3μm, which was smaller than that of potato starch (36.5μm) and edible canna starch (37.1μm). The susceptibility of Katakuri starch granules to hog pancreatin was higher than that of potato and edible canna starches, stripe structure and large holes on the center of which were observed by scanning electron micrographs (SEM). The amylose content of Katakuri starch was 22.8%. Average chain lengths of fraction II and III, determined by enzyme-chromatographic method, were 47.4 and 14.6, respectively, which were longer than that of the other starches. The initiation temperatures for gelatinization of Katakuri starch by photopastegraphic, differential scanning calorimetric (DSC), Brabender's viscographic and dynamic viscoelasticity measurements, were 45.0, 46.6, 54.2 and 47.0°C. Katakuri starch granules had high digestibility, and the initiation temperatures for gelatinization were lower than that of potato and edible canna starches by about 10°C.

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In our recent paper, we reported effects of heat-moisture treatments(120-135°C, relative humidity 100%) on the structures of several kinds of starches (potato, corn, waxy-corn, rice and waxy-rice), as studied by microscopic observations, X-ray diffraction measurements, and gel permeation chromatography. In this paper, we extend our study to examine the effects of heat-moisture treatments in terms of swelling power, solubility and viscosity of starch, and enzyme susceptibility with amylases. Although all starches changed their morphological features and granular structures, the mode and extent of change depended on the kind of starch and the condition used for the treatment. Among the sestarches examined, potato starch granules changed most their character by the treatment. The swelling power, solubility, and viscosity of gelatinized starch wered rastically decreased and the susceptibility to amylase were largely increased. Cereal starches, such as corn and rice starches, did not show large changes in these characteristic properties, but the changes observed were dependent on the kind of starch. Especially, rice starch showed an interesting change in viscosity parameters of amylogram which differs from other cereal and tuber starches as well.

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The addition of L-ascorbic acid (AsA) or dehydroascorbic acid (DHA) to wheat flour lowered the gelatinization temperature of starch about 2°C, and reduced the gelatinization enthalpy about 10% in comparison with that of the control or D-AsA. Farinography of wheat flour dough added with AsA or DHA showed a shorter development time than that with 2, 3-diketogulonic acid or the control, probably by the formation of SS cross-linkages of gluten molecules. Scanning electron microscopic observations of wheat dough after 25-min mixing with AsA or DHA suggested the changes in the rigidity of dough, followed by some changes in the wrapping of gluten to the starch granules. Considering these results, we discuss the changes of gelatinization temperature, enthalpy, gluten, and SH contents after addition of AsA and related compounds to wheat flour.

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Potato (cultivar, Danshaku-imo) was cultivated in lysimeters which are equipped in glass house, and was grown under a different condition of soil water by changing the ground-water level. Starch granules of potato grown under the dried soil, such as pF 3.0, suppressed remarkably gelatinization and did not show the maximum viscosity. However, the particle size, inorganic content, composition and structure of the starch did not change under the soil water conditions.

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In order to develop a durable bait for crustaceans, CD (a mixture of cyclodextrin and dextrin) was included in the cuttlefish-extract to control the release rate of cuttlefish-extract. Furthermore, the cuttlefish-extract included CD was kneaded with hydrophilic urethane resin, resulting in the softness similar to raw fishes which are conventionally used as baits for crustaceans. The release rate of the cuttlefish-extract that included CD was low compared with the extract without CD, indicating the effectiveness for the long-term use of the extract. The usefulness of the present cuttlefish-extract bait was demonstrated by the increase catch of crustaceans.

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