Susceptibility Of Starch Granules Research Articles

Sorptive properties of modified maize starch as indicators of their quality

AbstractThe physical and adsorptive properties of three products of modified maize starch in terms of the susceptibility of starch granules to surface processes as affected by their physicochemical diversity was compared in this study, using five mathematical models. It was assumed that modification of native starch is an important factor affecting its adsorptive properties. The products under study differed significantly in terms of the distribution of the size and shape parameters of their granules. The Guggenheim, Anderson and de Boer equation, characterised by relatively low sums of square deviations and low and similar errors of their different parameters, was the most useful in the description of empirically determined isotherms of adsorption. Parameters of the Guggenheim, Anderson and de Boer equation were used to estimate the parameters of the product surface microstructure. Modification of native maize starch differentiated the size of the monolayer, specific surface of sorption, and characteristics of capillaries.

High pressure impact on changes in potato starch granules

Abstract Air dry potato starch (84.9% d.s.) was subjected to pressurizing under the pressure of 50, 100, 250, 500, 750, 1000 and 2000 MPa for 1 h. The physical properties of pressurized starch, such as morphology, surface and crystalline structure, gelatinization parameters, were studied by means of scanning and atomic force microscopy (SEM/AFM), X-ray diffraction (X-ray), differential scanning calorimetry (DSC). The susceptibility to the amylolytic enzyme (α-amylase) was also measured. Application of pressure in the range of 50–2000 MPa results in an increase in the compressed potato starch bulk density, change in the contours of the granules from oval to polyhedral, increase in the roughness of the granule surface, vanishing of the X-ray reflexes generated by the orthogonal structure and weakening of the reflexes generated by the hexagonal structure, lowering of the enthalpy of starch gelatinization, and the enhancement of hydrolytic susceptibility of starch granules to the amylolytic enzyme.

The effect of temperature and time on the formation of amylose–lysophosphatidylcholine inclusion complexes

The formation of amylose inclusion complexes could help to decrease the susceptibility of starch granules against amylase digestion. We studied the formation of amylose–lysophosphatidylcholine (LPC) inclusion complexes at temperatures at and below the gelatinization temperature of starch, using DSC, CLSM and SEM. At temperatures below 50°C, only low amounts of complexes were formed; even upon prolonged incubation time (16 h). However, our results show that heating at 50–60°C, for prolonged times, leads to a nearly complete formation of inclusion complexes. Our study therefore indicates that gelatinization is not a prerequisite for inclusion complex formation. Also, the thermal characteristics of the gelatinization peak (onset temperature and enthalpy) are not affected by amylose–LPC complex formation.

Physicochemical and Structural Properties of Starch Isolated from Apios americana Medikus

Physicochemical and structural properties of starch isolated from tuberous roots of apios (Apios americana Medikus) were examined and these features were compared with those from arrowroot starch, potato starch and normal maize starch. The results obtained from the examination of apios starch were similar to those of arrowroot starch in X-ray diffraction pattern, solubility and swelling power, their behavior in the RVA, the susceptibility of starch granules to pancreatin digestion and the FE-SEM appearance as the digestion proceeded. The starch granules from apios showed Ca type in the X-ray diffractogram and had significantly lower swelling power at 70 and 80 °C than starch granules from potato. Apios starch granules had a rapid increase in solubility from 70 to 80 °C, and at 80 °C, it was higher than those of potato and normal maize starch granules. The susceptibility of apios starch granules to pancreatin digestion was higher than that of potato starch granules and lower than that of normal maize starch granules. The elution patterns of isoamylase debranched materials of the apios starch granules were similar to arrowroot and normal maize starch granules. The amount of amylose present in the apios starch granules (25.7%) was similar to the levels found in potato starch granules. Digestion of the granules was monitored by FE-SEM and varied between the different plant species. The differences in the structure of the starches lead to different susceptibilities to pancreatin digestion and the observed changes in the structural appearance of the granules as the digestion proceeds.

Studies on the Susceptibility of Granular Cassava and Com Starches to Enzymatic Attack Part I: Study of the Conditions of Hydrolysis

AbstractIn this research, the susceptibility of starch granules to enzymatic hydrolysis was studied. Cassava and corn starches were hydrolysed by bacterial α‐amylase with and without amyloglucosidase under several conditions of incubation. The highest percentage of hydrolysis was obtained in the presence of both enzymes. Elimination of the soluble hydrolysis products by dialysis increased the degradation of the starch granules, especially with cassava starch.

でんぷん粒の酵素糖化

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 (su2), 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.

Susceptibility of Starch Granules from Maize Endosperm Mutants to Amylases1

Abstract Starch granules were extracted from maize (Zea mays L.) endosperm of mature F2 kernels of IA5125 × IA453 normal, amylose-extender (ae), dull (du) waxy (wx), and ae du wx and from ae du wx F2 kernels harvested at the fresh market stage of development. Samples were digested for 1.5 hours with hog pancreatic α- amylase and Rhizopus II amyloglucosidase. The mature and immature ae du wx samples were usually digested significantly more than the other 4 genotypes, while ae was digested significantly less than the others. Digestion of starch granules from mature and immature ae du wx kernels did not differ. The sweet corn background used had little effect, since our observations of the single mutant genotypes were similar to those in a dent background. Clearly, ae du wx starch granules do not reflect the reduced digestibility associated with ae, and thus cultivars homozygous for ae du wx are not inferior with respect to their ability to supply carbohydrates to the diet.

Comparative susceptibility of starch granules of double- and triple-mutants containing Amylose-extender, waxy, sugary-1, sugary-2 and dull genes of maize inbred OH43 (Zea mays L.) to amylase.

Starch granules were prepared from 14 double- and 26 triple-mutants containing amylose-extender (ae), 14 double- and 18 triple-mutants containing waxy (wx), 15 double- and 20 triple-mutants containing sugary-1 (su1), 13 double- and 23 triple-mutants containing sugary-2 (su2), and 14 double- and 19 triple-mutants containing dull (du) of maize inbred Oh43 (Zea mays L.). The relative susceptibilities of these starch granules to fungal glucoamylase were determined and the starch granules were examined by scanning electron microscopy. A commercial normal maize starch was used as a control. Starch granules of the double- and triple-mutants containing su1 and su2 were digested two to eight times faster than normal. The ae gene reduced susceptibility and seems to be epistatic to su1 and su2. Starch granules of the double- and triple-mutants containing wx were digested about two times faster than normal and those containing shrunken-2 (sh2) were digested 1.2 to eight times faster than normal. Starch granules of triple-mutant combinations with opaque-2 (o2) showed digestion properties which were comparable to those of their respective monopaque double-mutant counterpart.

Comparative Susceptibility to Amylases of Starch Granules of Several Single Endosperm Mutants and Their Double‐Mutant Combinations with Opaque‐2 in Four Inbred Lines of Maize

AbstractThe relative susceptibility of starch granules of single mutants and double‐mutant combinations of maize and their normal counterparts to Rhizopus glucoamylase and pancreatin was compared and the relative degradation of starch granules followed by scanning electron microscopy. Starch granules of distinct endosperm mutants were resistant to the action of amylases whilst others showed pin holes on the surface and pores into the inner layers. Starch granules of the sugary, brittle, shrunken, and waxy mutants tended to be digested faster than those of their normal counterparts. The opaque‐2 mutant which improves nutritional quality of endosperm proteins did not change the susceptibility of starch granules to degradation by amylases.