The static viscoelasticity, stress-strain curves, texture profiles, and sensory evaluation for 10% katakuri (Erythronium japonicum DENCE) starch gel were compared with those for potato and edible canna starch gels. The creep curves for each gel measured at 10-40°C were analyzed by a mechanical model with four elements comprising a HooKEAN model, Vo1GT model for retarded elastic modulus and viscosity, and Newtonian model. The shift factor (log a_T) versus 1/T showed an inflection point at 26°C for potato starch gel. The apparent activation energy of katakuri starch gel was the smallest . Katakuri and potato starch gels resembled each other fairly well in stress-strain curves and hardness in texture profiles, although the texture profiles for katakuri starch had a shoulder which shows brittleness. Edible canna starch gel had the highest hardness and brittleness . The sensory evaluation demonstrates that there was no significant difference in the six evaluation items between katakuri and potato starch gels.

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Pectins were extracted from the dried fruit Crataegus sanguinea pall (Sanzashi in Japanese) with cold and hot water (neutral in pH), and then with an ammonium oxalate solution. Cold waterextracted pectin (C-pectin) showed the highest viscosity of these pectins, and the viscosity was much higher than that of commercially available lemon pectin. The enzymatic hydrolyzate of C-pectin showed much higher antibacterial activity than that of lemon pectin. A comparison of the activity of each oligomer revealed a correlation of the structure with the activity of the oligomers. That is, an oligomer should not be ionized, and should be at least 5 to 6 in DP.

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Occasionally, commercial sweetpotato starch is unfavorable due to odor and whiteness. In this study, the characteristics resulting from the adsorption of some compounds into commercial starches were examined; the compounds are considered to cause a qualitative deterioration of the starch granules. Each starch adsorbed a similar amount of lactic acid, and the respective Nägeli amylodextrins (NA) adsorbed comparable amounts. In regard to butyric acid, no difference in the amounts adsorbed into the starches was found either, but the amounts adsorbed by their NA were significantly less than those by the starch granules. On whiteness of the starches, both polyphenol (chlorogenic acid) and iron ion were indispensable for grayish color development of the starch granules. The amounts of chlorogenic acid adsorbed into the starches were nearly identical, except for potato starch which scarcely adsorbed it. Thus far, no characteristic adsorbability of sweetpotato starch has been recognized. However, regarding the adsorption of ferric chloride, unusual adsorbability was found in sweetpotato starch.

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Wheat starch granules were perfectly damaged but not cracked to pieces with rolling type ball-mill treatment for a long period (320 h), however, the granule surface changed from smooth to rough. The properties (amylase susceptivity and water absorption activity) of treated starch changed distinctly after 10 h of treatment. DSC results and X-ray diffraction patterns of treated samples also showed the same tendency. It was concluded that ball-mill treatment gelatizes starch granules over 10 h without water and heat. GPCs of a starch sample and a debranched sample showed that amylopectin was degraded and the cluster size fragment possibly liberated. Long-term treatment makes the molecular size of both components of starch small. A HPAEC analysis showed the liberation of very short chains with long-term treatment. A ¹³C solid-state-NMR spectra of starch samples suggests that disruption occurs at the glycosidic linkage during treatment.

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Starch of halotolerant microalgae Dunaliella was isolated and some properties were investigated. The starch content of the algae reached about 10% after 10 days' cultivation. This starch content was larger than that of Chlamydomonas reinhardtii, which is a relative species of Dunaliella. Although the crystal structure of the starch seemed similar to the starch of maize, the gelatinization temperature of the starch was 10°C lower. Gelatinization temperatures of the starch from Dunaliella cultured at different temperatures indicated that the change in gelatinization temperature depends on the temperature during cultivation. The same phenomenon was also reported about the gelatinization temperature of certain microalgae and plants. Nitrogen starvation caused a significant increase in the starch content of Dunaliella parva. Since some kinds of lipid droplets were also observed in the starch-accumulating cells, nitrogen starvation may be useful to improve the values of Dunaliella cell for the biomass.

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The kinetic characteristics of the Aspergillus niger β-glucosidase-catalyzed reaction for the pNPG and G2 substrates, where the v-[S]₀ plot does not show the Michaelis (saturation) curve, was consistently explained not by the transfer reaction but by substrate inhibition. The reactions ere carried out in the presence of acetonitrile CH₃CN (ε≅38) : transglucosylation was not confirmed for the βGA-catalyzed reaction. Moreover, CH₃CN was found to have an effect on (increase in) the kinetic parameters K_S and K_S′, resulting in support of “hydrophobic-driven” ES-complex formation, a proposal presented in a previous study.

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The rheological properties of k-carrageenan isolated from Ibaranori (Hypnea charoides LAMOUROUX) were studied with a rheogoniometer. The solution of Na-salt of k-carrageenan, at 25°C, showed Newtonian behavior at a concentration below 1.0%, whereas the K-salt showed plastic behavior even at 0.3%. The transition temperature, at which dynamic viscoelasticity decreased rapidly, was observed at 15 or 20°C at various concentrations of the K-salt of k-carrageenan. Gelation occurred for the Ksalt of k-carrageenan at a concentration of more than 0.5% at low temperature (0°C), but not for the Na-salt even at a concentration of 2.0%. A very large dynamic viscoelasticity was also observed on the addition of 0.1% KCl to a 0.2% solution of K-salt of k-carrageenan. The gel formation of the kcarrageenan isolated from Ibaranori might be attributed to intra- and intermolecular K⁺-bridges within and between molecules.

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Bacillus macerans cyclodextrin-producing enzyme (CGTase) was precipitated by the addition of trichloro acetic acid (TCA) at pH 2.1. After washing with water, dissolving in 0.1 N NaOH, adjusting the pH to 6.0, and freeze drying, powdered CGTase (p-CGTase) was prepared. p-CGTase was dissolved in a buffer and treated at various temperatures (50-100°C) to obtain a heat-treated coagulated protein (cp-CGTase). The protein was dissolved in an alkaline solution and neutralized with an acidic solution to pH 6.0, and the recovered activity was measured. The activity of p-CGTase was completely inactivated at over 70°C and the cyclodextrin-forming pattern of the recovered enzyme was not changed, but a considerable amount of activity was recovered using cp-CGTase; nearly 40% of activity was recovered after an 80°C treatment. It was infered that the free-enzyme protein is folded and coagulated to maintain activity at high temperature .

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Although it has been generally accepted that the starch components are synthesised from ADPG by the combined action of various multiple forms of starch synthase and branching enzyme, the recent literature contains suggestions that debranching enzymes are also involved in this biosynthesis. In particular, a discontinuous synthesis model involving phytoglycogen-processing by a debranching enzyme has been proposed as a mandatory step in the biosynthesis of starch . However, a critical review of the literature shows that this model is not compatible with many of the properties of both the branching and debranching enzymes present in the majority of higher land plants . It is concluded that in these plants, amylopectin-type molecules can be synthesised from ADPG by starch synthases and branching enzymes without the involvement of any debranching enzyme .

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