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Starches with different amylose (AM)/amylopectin (AP) ratios (waxy potato: WxPS; regular potato: PS; high AM corn: HACS) are hydroxypropylated (HP, two levels) and subsequently acid‐thinned (AT) to produce dual‐modified samples. The physicochemical characteristics and techno‐functional properties of the solutions are investigated, and the data are evaluated statistically (analysis of variance). Differential scanning calorimetry gelatinization experiments reveal a reduction of the transition temperatures particularly due to HP. The subsequent AT decreases the specific enthalpy significantly. HACS samples have lower solubility (S) compared to their potato‐based counterparts (WxPS and PS), but HP enhances the starch's S. The S of the AP of the HACS samples is comparatively high, and HP particularly facilitates the additional solubilization of AM. Dual‐modified samples show characteristics of S similar to the corresponding HP samples. Or particular note, the HP‐modified WxPS and PS, respectively, tend to cause molecular degradation of the polymers dissolved. The hot paste viscosity is impacted significantly by all varied factors. [ABSTRACT FROM AUTHOR]

Granular potato starch is modified using the debranching enzyme isoamylase. The modification is performed in aqueous suspension (40% w/w) at 35 °C by grading the volume (100, 250, and 400 µL/50 g of starch, 200 U · mL−1) of enzyme solution added. The starch products obtained are comprehensively investigated in terms of morphological (scanning electron microscopy), structural (X‐ray diffraction), thermal (differential scanning calorimetry), techno‐functional (solubility, hot paste viscosity, gel strength), and molecular properties (size exclusion chromatography‐multi angle laser light scattering‐differential refractive index detection). The granular integrity is basically preserved after modification and a molecular degradation predominantly of the amylopectin by debranching is proved. However, a slight reduction of the weight average molar mass of the amylose fraction is found too. In addition, the intended partial molecular degradation of the starch polysaccharides, the effect of the preparation procedure including washing with ethanol and grinding impacts several starch characteristics conspicuously. [ABSTRACT FROM AUTHOR]

The use of dietary fiber enriched flour for bread making is steadily gaining importance because of its proven health benefits. The objective of the work was to assess the impact of xanthan (XG) and guar gum (GG) on the pasting profiles, stickiness and extensional properties of β-glucan incorporated brown wheat flour (BWF/BGC) composite dough systems. Water absorption of the blend flour increased significantly with increasing the concentration of hydrocolloids. Loading of both hydrocolloids (0.125–0.5 g/100 g) produced similar values of extensograph and stickiness parameters, nonetheless, it was observed that an addition of 0.25 g/100 g hydrocolloid could be effective to maintain a desirable dough texture. Biaxial measurement indicated that the incorporation of 0.25 g/100 g hydrocolloids improved the dough structure of BWF/BGC. The pasting viscosities of the blend dough including hot paste, cold paste and final viscosity increased significantly with increasing the hydrocolloids concentration. The pasting properties of BWF/BGC influenced by individual hydrocolloid, and the difference could be attributed by the complex formation among swelled starch, leached amylose and hydrocolloids. [ABSTRACT FROM AUTHOR]

Influence of high-pressure (HP) treatment (400-600 MPa, 10 min) on chestnut flour (CNF) dispersions was examined. The particle size, total starch, and resistant starch contents were not influenced by the HP treatment. DSC, XRD, SEM, and rheometric measurement confirmed that the applied pressure was not adequate for the complete gelatinization of the chestnut starch in the dispersion. The mechanical rigidity of CNF in dispersions (flour/water = 1:2) increased significantly with increasing the pressure. Pasting profiles of the HP-treated sample varied significantly from the sample without the pressure treatment. Overall, the work revealed that chestnut starch was pressure-resistant within the studied pressure range. [ABSTRACT FROM AUTHOR]

Acid-thinned wheat, potato, and pea starch products were systematically prepared applying gentle conditions with variation of acid type (HCl and H2SO4), acid concentration (0.36 and 0.72 N in a 40% (w/w) suspension) as well as hydrolysis time (4 and 24 h). Starch granule properties as well as molecular and rheological characteristics in the solution state were analyzed and the impact of all parameters varied was found to be immense. Carbohydrate solubilization of wheat and potato starch was significantly higher compared to pea starch. Noteworthy progress in solubilization was found when hydrolyzed with HCl, and with increasing acid concentration and increasing hydrolysis time by trend. The hydrolysis affected the reduction of the hot paste viscosity most dominant in the first period of treatment (0-4 h), however, size exclusion chromatography-multi angle laser light scattering (SEC-MALS) analysis revealed a more prominent molecular degradation during the second period (4-24 h). This observation led to the interpretation that the molecular degradation in the initial phase results particularly in 'debranching' of the high molar mass amylopectin fraction and lower hot paste viscosity. Continued hydrolysis with significant reduction of the molecular size, however, had reduced impact on further lowering of viscosity. SEM micrographs displayed intact pea starch granules with unchanged surface after hydrolysis, whereas wheat and potato starch granules were visibly affected with damage not evenly distributed but a variation over the granule population. Granular wheat and potato starch exhibited significantly enhanced particle size after short period modification measured in water. However, this was found eliminated at extended hydrolysis time. Reasons were hydrolysis induced molecular rearrangement resulting in better crystalline packing on the amorphous/crystalline threshold reducing the ability to swell, and the progress in granular erosion. That was in line with changed swelling characteristics determined using DSC. The study gave evidence for strong impact of acid hydrolysis on functional properties like water binding. [ABSTRACT FROM AUTHOR]

Scanning electron microscope (SEM) pictures of small millet starch granules showed more large polygonal and few small spherical or polygonal granules. The granules of small millets resembled those of rice starch granules. The size of the starch granules ranged from 0.8–10 μm. The size of the granules was larger in barnyard millet and smaller in proso millet. Several granules showed deep indentation caused by protein bodies. SEM of starch isolated from 24 hour-germinated kodo millet showed pitting or pinholes at some points due to the attack of amylases (preferentially on bigger granules). Brabender viscoamylograph studies on small millet starches revealed that the gelatinization temperatures ranged from 75.8 to 84.9 ° C. Barnyard millet possessed lower amylograph viscosity, minimum breakdown, and relative breakdown values when compared to the other small millets. [ABSTRACT FROM AUTHOR]

A matrix of 27 acid‐thinned (AT) potato starch (PS) samples is prepared in a laboratory scale in slurry by gradation of the process parameters temperature (30, 40, and 50 °C), acid concentration (0.3, 0.6, and 0.9 m HCl) and time (4, 10, and 20 h), and is investigated in terms of functional properties (range of molar mass [Mw] between 17.7 × 106 and 1.95 × 104 g mol−1). The solubility (S) increased basically with a higher degree of molecular degradation and disintegration temperature, and the viscosity decreased systematically with decreasing Mw and increasing disintegration temperature. The existence of a specific Mw range of the starch to achieve highest gel strength is proved. However, an impact of the molecular properties on the light transmittance (Tgel) can be excluded, since all starch gels are opaque. A correlation between the strength and the specific non‐freezable bound water content (wnf) of the gels is found. High gel strength is accompanied by comparatively low wnf. In particular, the viscosity (processing) and the gel strength (final product characteristic), which are important technofunctional properties for the industrial application of AT starches, are found to be directly correlated to the Mw of the starch product. Moreover, the latter is controllable by the hydrolysis process parameters. [ABSTRACT FROM AUTHOR]