Cellulase (EC 3.2.1.4, β-1, 4-glucan glycanohydrolase from Aspergillus niger) was fixed on polyacrylonitrile resin by amidination with methylimidate-hydrochloride of polvacrvlonitrile . The enzyme protein was fixed up to 17?Eg per 1 mg of carrier, and the yield of fixed cellulase protein was about 50% of added native enzyme in the reaction system. The activity fixed cellulase was about 20% comparing to the equivalent native cellulase. The optimum pH was slightly moved to the alkaline side by the fixation and it was 4 .2 for native cellulase and 4.6 for fixed cellulase . The optimum reaction temperature of the fixed enzyme was found to be slightly shifted to the lower temperature (49°C for native cellulase and 47°C for fixed cellulase). The apparent activation energy of fixed cellulase and native cellulase to CM-cellulose was estimated to be about 11 kcal/mol and 9 kcal/mol respectively . As for the stability of both enzymes towards the changes of preincubation pH and temperature, following results were obtained: The relative activity of the fixed enzyme decreased more sharply at the both sides of it's optimum pH than the native enzyme in the pH range from 2 to 10. An increase in enzymatic activity (V/Vuntreated=1.3) was found when the fixed cellulase was preincubated at 40°C for 15 min in distilled water. However, at the higher incubation temperature, fixed enzyme lost it's activity more rapidly comparing to the native cellulase. Further, the activity increase (V/ Vuntreated =1.2) was recognized when the fixed cellulase was stored at 18°C for 30 hr.

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In order to clarify the change of physicochemicall properties of irradiated starches, fractionated amylose and amylopectin from amylomaize starch were treated with five different doses of gamma irradiation up to 110⁶ rad. The samples were characterized by the determination of intrinsic viscosity, formation of free reducing groups, iodine absorption spectra, alkali number and amylase digestibility. Irradiated samples of both amylose and amylopectin decreased in viscosity and iodine absorption, and increased in reducing value and alkali number. These results indicated that both amylose and amylopectin were degraded in the same manner as intact starches by gamma irradiation. Amylose, however, was more sensitive to this treatment than amylopectin. Both fractionated components of amylomaize starch were unchanged in α-amylase digestibility after irradiation compared with non-irradiated samples. On the other hand, irradiated amylose showed a marked change in the β-amylolysis limit; it was gradually lowered in the β-amylolysis degree as increasing the radiation dose. Irradiated amylose with a dose of 1×10⁶ rad decreased in β-amylolysis degree approximately 14% than non-irradiated sample. The low β-amylolysis limit of irradiated amylose was not restored to that of non-irradiated sample even by concurrent action of β-amylase and pullulanase.

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When oxidized fat or oil reacts with foodstuffs, the taste, flavor and texture of food are enormously changed. Experiments were carried out to study the effects of oxidized oil on the physico-chemical properties of starches. Corn and potato starches were dipped in the oxidized linseed oil at 40°C for various period of time. After removal of excess oil with chloroformmethanol, the treated starches were examined and the following results were obtained .1) Gelatinization temperatures in amylograms and photopastegrams of corn and potato starches which were treated with oxidized oil were lower than those of normal starches.2) The maximum viscosities of amylograms in corn and potato starches treated with oxidized oil were lower than those of normal starches.3) In the rheological properties determined by rheolometer, hardness and adhesiveness of the treated corn starch gels were decreased, and in contrary, those of the treated potato starche gels were increased.4), -amylolysls limits were decreased in the treated corn and potatO Starches compared with those of normal starches.5) Reducing sugar was increased in the treated corn starch, and no change in potato starch. It was observed thal the content of caprylic acid was increased in the oxidized oil. It is suggested that the changes in physico-chemical properties of oxidized oil treated starches were partly attributed to the introduction of short chain fatty acid into starch molecule.

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Potassium, sodium and calcium contents of starches are ordinarily determined by atomic absorption spectrophotometry (AAS) after dry ashing. In the case of potato starch which has a high content of phosphate, the ordinary method did not give satisfactory results, especially for the determination of calcium content because of the interference of coexisting potassium and phosphate. We describe here a novel method to determine cations bound to potato starch accurately. After comparison of various preparative methods of samples for AAS, we have obtained the best result by the 1% HCl extraction of cations from starch, instead of dry ashing in a born-silicate glass beaker or a platinum dish, for the AAS of sodium, potassium and magnesium. Combination of the 1% HCl extraction and the improved AAS, where excess amounts of K⁺ and PO₄^3- (500-1, 000 ppm) were added, was extremely effective for the calcium determination. The addition of K⁺ and PO₄^3- stabilized the determination of calcium even though the existence of end genous potassium and phosphate. The results of the determination by various methods are shown in this paper for the potato starches prepared in laboratory and commercially. For the accurate and simple determination of cations of potato starch, we recommend the method to extract cations from potato starch with 1% HCl followed by the ordinary AAS for potassium, sodium and magnesium. For the determination of calcium in the extract the improved AAS is recommended to eliminate the interference of coexisting potassium and phosphate.

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In our production of starch sweeteners, occasionally the high COD contents were found in the wastes from the ion-exchange refining. Analyzing the effluents from the regeneration of anionic ion-exchange resin with which the starch hydrolyzates of the various raw material were refined, it is suggested that a large amount of the phospho-dextrins remained without being hydrolyzed and were adsorbed on the anionicion-exchange resin when the potato starch was used as the raw material.

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