Ash contents and inorganic constituents of the starch samples prepared from potatoes cropped at the five Agricultural Experimental Stations in Hokkaido were determined. Their viscosity and distribution in granule size were also measured. The five Experimental Stations were located at Shibetsu, Memuro, Shari, Shimamatsu and Nakashibetsu respectively. The varieties of the potato samples were Normn No. 1, Benimaru, Shiretoko, Danshaku, Eniwa, Hokkaiaka, Tarumae and Bihoro. The experimental results were summarized as following;1. The ash contents of starch prepared from potatoes cropped at the Shibetsu and Memuro Station showed higher values than those of the other three samples. Among the three low ash members, the starch from Shari showed rather high ash content.2. The main constituents of the inorganic components of each starch sample were found to be phosphorus and potassium.3. Viscosity of each starch sample was measured by means of Brabender Amylograph. The peak viscosity of starch samples prepared from potatoes cropped at the Shibetsu and Memuro stations showed higher values than those of other samples.4. Starch samples prepared from Bihoro and Benimaru potatoes showed higher contents of large starch granules as compared with those from Shiretoko, Danshaku and Normn No. 1.

View full abstract

As previously reported, potato starch gives a refracting point on the sharply ascending part in its amperometric iodine titration curve, but corn starch gives no such point. It has been considered that the difference between these two kinds of starches is not due to their amylose components but to amylopectin components. In the present paper, the difference between the amylopectins was examined from two points of view: (1) it was considered that the esterified phosphate on starch molecules is independent of the difference in shapes of the titration curves, because the high phosphate corn starches prepared by roasting corn starch with sodium phosphates still gives no refracting point on the curves; (2) it was considered that the difference between the titration curves is dependent of some structural difference in inner part of amylopectin molecules, because β-limit dextrin from potato amylopectin gives essentially the same shape of the titration curve as that of the original amylopectin.

View full abstract

The wastewater were passed through three columns containing 220-350 g granular activated carbons, and the adsorption of the compoments were investigated . Results obtained were as follows; 1) Granular activated carbons were not effective for adsorption of organic substances but effective for that of H₂SO₃ in wastewater from corn starch factory . 2) For the waste water from corn starch and bean-jam making factories, the removal of COD were 80.2% and 89.5%, respectively. Consequently, the average COD (mg) adsorbed by the activated carbons (g) were 70-80% and about 50% for that of adsorption isotherms in previous paper, respectively.

View full abstract

The wastewater were passed through a column containing 20 g of the following activated carbons†, and the adsorption of the components were investigated. †A, D and E: for liquid refining, B, C, F and G: for water purification . Spherical activated carbons: manufactured for trial in National Research Institute for Pollution and Resources. Results obtained were as follows: 1) A, D and E were effective for adsorption of organic substances in the range of initial COD 1, 000-4, 000 ppm. 2) The COD removal rate in A and spherical ones after treated 480 ml wastewater were 92.5% and 75-87%, respectively. 3) The average amount of COD adsorbed by the activated carbons was 85% of that in the adsorption isotherms in previous paper.

View full abstract

By using the substrates of defined anomeric form, with very brief incubation to limit mutarotation, evidence has been obtained that the condensations require donor substrates of specific configuration. That is, crystalline glucoamylase from Rh, niveus has been found to catalyze the rapid synthesis of maltose and a slower synthesis of isomaltose specifically from β-D-glucopyranose. Crystalline sweet potato β-amylase, likewise, has been found to catalyze the rapid synthesis of maltotetraose specifically from β-maltose, and crystalline hog pancreatic α-amylase the rapid synthesis of maltotetraose specifically from α-maltose. A rapid approach to equilibrium was found both in maltose synthesis from, β-D-glucopyranose by glucoamylase, and in maltotetraose synthesis from β-maltose by β-amylase. Moreover, essentially the same equilibrium (Keq=ca. 0.13) was reached by these homologous hemiacetalto-secondary carbinol condensations. The configurational inversion accompanying both condensations, finally, reveals their mechanism as one of glycosyl transfer. Crystalline a-amylases from six different biological sources, as well as crude salivary amylase, were examined and found to catalyze the synthesis of maltose and maltosaccharides from α-D-glucopyranosyl fluoride, a stereoanalog of α-D-glucopyranose. The entire group of a-amylases had the capacity to promote α-D-glucosyl transfer from α-D-glucosyl fluoride to C4-carbinol sites, demonstrating for the first time that α-amylases possess in common the capacity to catalyze glycosylation (i. e., glycosyl-hydrogen interchange) reaction extending beyond hydrolysis and its reversal. Similar de novo synthesis of maltosaccharides from α-maltosyl fluoride by a-amylases was also discussed.

View full abstract