In general, the raw starch contains small quantities of crude protein, oil, resin, and inorganic salts as impurities. By the washing of raw starch with surface active agents, the content of protein in starch was considerably decreased and the purity of starch was rised.
Furthermore, the addition of surface active agents to raw starch was found to be effective for complete inhibition of its deterioration, especially D. B. S. (dodecyl benzene sulfonate) was predominant.
Then the author has studied the mechanism of preventing deterioration, and this was attributed to the combination of D. B. S. and proteins of the organisms to give a metaprotein by bacteriolysis.
This phenomenon is closely related with formation of surfactant-protein complexes.
In this study on fatty substances in the raw starch and removal of “fat-by-hydrolysis” by the surface active agents, it was found that fat-by-hydrolysis in starch could be removed to some degree by washing with the surfactants, as well as with the organic hydrophobic solvents such as methanol, and there might be a posibility of the surface active agents being introduced into the helix structure in starch.
Furthermore, regarding the effect of fat-by-hydrolysis on physical properties of starch, it was shown that gelatinization temperature and viscosity of starch paste rised in proportion to the quantity of fat-by-hydrolysis.
The investigation of the introducing of fatty acid into the starch has shown that physical properties of starch treated by surface active agents were conciderably different from untreated starch. When the starch was treated by sodium salts of fatty acids, it forms a complex with amylose, and treated starch showed a distinctive curve on the amylograph.

View full abstract

Starch granules involve various amounts of fatty acids as “Fat by Hydrolysis” in different plant sources. These fatty acids are possibly embraced in amylose component and concerned in affecting some properties of the granules, but it is not yet clear through what process they are embraced into the granules in vivo.
In this study, starch samples differing in granular size were prepared from sweet potato tubers of different maturity, and were studied on quantative and qualitative changes in the embraced fatty acids and transitions of some chemical and physical properties with the development of granular size.
Each X-ray diffraction pattern of the samples of small granules was clearly characterized by the respective season when the tubers were harvested. This suggests that the small granules have developed just before the harvest. Such starch granules in earlier stage of development were shown to be higher in contents of both amylose and the embraced fatty acids, the major component of which was palmitic acid. Both contents decreased with the development of granules, while the quantity of oleic acid incorporated was found to be approximately constant throughout the developing duration.
These results suggest that palmitic acid contributes to the occurrence of starch granules in vivo, because incorporation of palmitic acid into amylose may result in repressing the free movement of amylose molecules and in bringing about formation of amylose gel.

View full abstract

The new method was described in this paper to determine oligosaccharides quantitatively by an improved densitometry. The principle of the method consists of the combination of densitometry and a glucoamylase-maltase treatment of weak reducing maltooligosaccharides on the filter paper. By this enzyme treatment, high maltooligosaccharides which were revealed weakly by the silver nitrate reagent, were strongly enhanced their intensities.
The optimum conditions of the enzyme treatment was studied in connection with that of densitometry.
A developed paperchromatogram was dipped in 80% aqueous acetone solution of enzymes which contained glucoamylase or the mixture of glucoamylase and maltase. The dipped chromatogram was incubated for 1 hour at 40-45°C in a moisture saturated chamber. During the incubation, all the maltooligosaccharides were converted to glucose. This procedure enabled to detect a trace of oligosaccharides as a strong stain with the silver nitrate treatment.
Using this method, we could determine the quantity of maltooligosaccharides of the level of 5μg within the experimental error of 10%.
The time course and the enzyme activity determination of the maltohexaose producing amylase obtained from Aerobacter aerogenes was presented as one of the example of this method.

View full abstract

The characteristic sugar spot, which was found most prominently on the paperchromatograms of the digests of yeast glucan and pachyman by a glucanase from an Arthrobacter bacterium, was identified with laminaripentaose. The less conspicuous sugar spots accompanying the above one were the individual members of a homologous series of β-1, 3 laminaridextrins; the presence of the dextrins having DP's up to 10 was confirmed.

View full abstract

Bacterial disinfestation in the microwave treatment of starch was determined:
(1) The microwave treatment of starch for the period of three minutes reduced the viable count of the starch samples to the extent of 37-75%.
(2) When the moisture content of starch was increased from 16.5% to 26%, disinfestation effect of the microwaves was enhanced, although partial gelatinization of the starch occurred after two minutes.
(3) The resistance of thermophiles isolated from starch samples was tested in water with microwave treatment. The susceptibility of the isolates to the microwave treatment was similar to that to heat treatment, the survival was, however, greater with the latter than with the former.

View full abstract

Short column sedimentation equillibrium method was applied to the determination of molecular weight of the low molecular compounds, especially, oligosaccharides. Theoretical consideration about the basic equillibrium equations were made on the ideal mono-dispersed, non-ideal mono-dispersed and ideal poly-dispersed solutions, then the two new computation methods of molecular weight were proposed. An error caused by the pressure effect was also estimated, and the relation between the error and the solvents properties was showed that the most preferrable solvents usable for the molecular weight determination of the low molecular oligosaccharides were water and alcohols. Experimental application of the above method on oligosaccharides such as maltose, lactose, raffinose and their mixtures gave the good results, consisting with the theoretical values.

View full abstract