- 著者
-
不破 英次
- 出版者
- 日本応用糖質科学会
- 雑誌
- 澱粉科学 (ISSN:00215406)
- 巻号頁・発行日
- vol.29, no.2, pp.99-106, 1982
- 被引用文献数
-
5
Starch granules of roots and tubers were, in general, more resistant to the action of amylases than those of cereals. However, taro starch granules were highly susceptible and starch granules of banana, high-amylose (amylose-extender, ae) maize and gingko were rather resistant to the action of pancreatin compared with those of normal maize. The susceptibility of starch granules to degradation by amylases depends not only on the source of the starch but also of the amylase. Three different types of α-amylase, namely, purified α-amylase of Streptonnyces precox NA-237 (SE-1), porcine pancreatic α-amylase (PPA) and crystalline α-amylase of Bacillus subtilis(BLA), degraded starch granules of sugary-2 (su<SUB>2</SUB>), waxy (wx), normal and ae maize in decreasing order. However, the amounts of enzymes necessary for 10% hydrolysis of starch granules in 1 hr were SE-1: PPA : BLA =1:5:6 for sue, 1:30:930 for wx, 1:28:1340 for normal and 1:110:1046 for ae, respectively. For starch-granule susceptibility to glucoamylase of Rhizopus amagasakiens (crude preparation); 1) Starch granules of waxy-type cereals were, in general, more susceptible than those of their normal counterparts. This was shown for rice, barley, proso millet, maize and job's tears starch granules. 2) Fine starch granules of taro and grain amaranths were highly susceptible. Among the same species, smaller starch granules were more susceptible than larger ones. This was shown for potato and barley starch granules. 3) Negative correlation between starchgranule susceptibility to glucoamylase and absorptivity at 680 nm of iodine complex ("blue value") was obtained for various starches. Exceptions were dull(du) and sue maize starches. Also results indicated that 1) in general, X-ray diffractograms of starch granules relatively susceptible to amylases were A type, those of starch granules insusceptible to amylases were B type and those of starch granules intermediately susceptible to amylases were C type. 2) Photopastegrams showed two-step increase of transmittance for starch granules relatively susceptible to amylases and one-step increase of transmittance for starch granules insusceptible to amylases. 3) By scanning electron micrography (SEM) of various starch granules, we confirmed that starch granules susceptible to amylases showed polygonal shapes but starch granules insusceptible to amylases had smooth surfaces and round or oval shapes.