Three glucoamylases, two debranching enzymes and two α-glucosidases were examined either singly or in combination with one another to breakdown isomaltose and panose which are produced during the hydrolysis of starch as byproducts, thereby leading to poor conversion efficiency. Such oligosaccharides rich fractions collected from starch industry or prepared from maltose by the transglucosylase action were used as substrates for enzyme action. Of these enzymes, the α-glucosidases, either singly or in combination with glucoamylase could breakdown panose and isomaltose completely at low substrate concentrations. The combination of glucoamylase and maltase (commercial product; α-glucosidase of Rhizopus origin) was found to be best in being able to hydrolyze these byproducts even at high glucose concentrations. The possibility of such an enzyme system being used in industry is discussed.

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Glucoamylase II was found to be very predominant in one glucoamylase preparation of black Aspergillus. It had a weak debranching activity (0.19) but it could hydrolyze β-limit dextrin from glycogen almost completely unlike glucoamylase II of Aspergillus awamori or Aspergillus oryzae. It could not be adsorbed onto raw starch but could be easily adsorbed onto chitin. The optimum pH for raw starch digestion by this enzyme was 3.5. Glucoamylase II was about 5 times weaker than glucoamylase I in raw starch digestion. Raw starch digestion by the combined action of glucoamylase II and pullulanase occurred optimally at pH 5.0 and not at pH 3.5. However, pullulanase hardly stimulated raw starch digestion by glucoamylase II. Similar findings were also obtained in case of glucoamylase I of the black Aspergillus.

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Seasonal changes of starch content in wild Alocasia odora stems grown at half-shaded place were studied. It varied from 60% of dry weight in November and April to the maximum value of 78% in February. Scanning electron microgram of alocasia starch revealed the polyhedral granules with their diameters ranging from 1 to 3 gym. These features of alocasia starch are close to those of colocasia starch. Susceptibility of alocasia starch toward Bacillus subtilis α-amylase and Rhizopus glucoamylase was compared with those of clocasia, cassava, sweet potato and potato starches. Gelatinized alocasia starch was hydrolyzed as rapidly as other starches by B. subtilis α-amylase. Moreover, hydrolysis limit of this starch was less than 60% at most whereas those of other starches were 67 to 70% under the same conditions. On the other hand, alocasia starch granules were most susceptible among the starch granules tested to B. subtilis α-amylase and Rhizopus glucoamylase. It is suggested that the observed features of alocasia starch may be due to the highly branched structure of its amylopectin.

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A review with 88 references exclusively of the author and of him and his collaborators. The legumes studied are Arachis hypogaea, peanut; Vicia faba, broad bean; Pisum sativum var, arvense, smooth pea; Phaseolus vulagris, kidney bean; Vigna radiata, mung bean; V. angularis, adzuki bean; V. unguiculata ssp. sesquipedalis, asparagus bean; Dolichos lablab, hyacinth bean; Canavalia gladiata, sword bean; Glycine max, soybean; and Stizolobium hassjoo, Yokohama bean. Special attention was paid to the starches and non-starchy polysaccharides, especially hemicelluloses of soybeans and broad beans. Also studied were the oligosaccharides of legumes, i. e. sucrose, raffinose, stachyose, verbascose, and ajugose. D-Pinitol was isolated from soybeans and was fully identified.

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