Supramolecular structure of A- and B-type granules of wheat starch

The Comparison of Structural, Physicochemical, and Digestibility Properties of Repeatedly and Continuously Annealed Sweet Potato Starch

In order to investigate the varied effects of repeated annealing treatment (RANN) and continuous annealing treatment (CANN) on the structural, physicochemical, and digestibility properties of the sweet potato. The 75% starch-water suspensions were prepared and incubated at 65 °C for 8 cycles and 96 hr. The results exhibited that RANN and CANN did not influence the starch granules and polarization cross obviously. The crystal type of RANN and CANN starches still maintained A-type, while the relative crystallinity increased. The solubility, swelling power, peak viscosity and breakdown of RANN and CANN starches decreased, but the gelatinization transition temperatures, trough viscosity, final viscosity, setback, and pasting temperatures of starches increased after annealing treatments. Furthermore, RANN and CANN decreased the RS and RS + SDS contents with the increase of annealing cycles and time. The RANN was more effective in modification of the crystallinity, solubility, swelling power, pasting, gelatinization transition temperatures and enthalpy, and digestibility of starch before four times compared with the CANN ones. By and large, RANN may be a potential way for modification of structural, physicochemical and digestibility properties. PRACTICAL APPLICATION: The described RANN and CANN starch provide new ideas for the study of modified starch. Furthermore, this study revealed the mechanism of annealing treatment and it was concluded that the repeated annealing treatment could provide a new potential way for the modification of starch.

A Review on the Source of Lipids and Their Interactions during Beer Fermentation that Affect Beer Quality

The presence of lipids in wort and beer are important due to their influence on yeast metabolism and beer quality. Barley lipids have long been considered to have adverse effects on beer quality where some long-chain fatty acids are associated with high flavour potential. In addition, beer foam stability can be influenced by the concentration of lipids as well as other factors such as hop acids (e.g., iso-α-acids), proteins, polysaccharides and the presence of metal ions (e.g., nickel). Lipids can also influence yeast protease activity as well as the production of ethanol. This review provides an overview of the effect of climate change on the chemical composition of barley in relation to lipids and the influence of lipids in the process of this raw material in order to produce beer.

Physicochemical Properties of A- and B-type Granules of Wheat Starch and Effects on the Quality of Wheat-Based Noodle

This work fractionated native wheat starches into A- and B-type granules fractions to accurately assess granules physicochemical properties and effects on water distribution, storage modulus (E′) and loss modulus (E″) of two type noodles with A- and B-type granules. Pasting viscosity and starch crystallization of A- and B-type granules were determined by Rapid Visco Analyzer (RVA) and X-ray diffraction (XRD) respectively. The noodles were prepared from wheat flour, which 20 % was replaced with the A or B starch fractions, respectively. The water distribution and dynamic mechanical properties of noodles were characterized through Low-field Nuclear Magnetic Resonance (LF-NMR) and Dynamic Mechanical Analysis (DMA). The results demonstrated that A- and B-type granules almost had a round shape with smooth surface. The crystal models of A- and B-type granules were the same but the relative crystallinity were different. A-type granules contained higher starch content, higher ratio between amylose and amylopectin and less damaged starch than B-type granules. B-type granules easily aggregated into clump in deionized water. A- and B-type granules were different in swelling properties and pasting viscosity under the same conditions. A-type granules possessed lower swelling power and water-binding capacity, higher solubility and pasting viscosity than B-type granules. A-noodles (relative to B-noodles) had higher ratio of immobilized water, E′ and E″.

Digestibility and supramolecular structural changes of maize starch by non-covalent interactions with gallic acid

The synergistic effect of starch–GA complexes with more ordered multi-scale structures and the released GA inhibition decrease starch enzymatic digestibility.

Effects of removal of surface proteins on physicochemical and structural properties of A- and B-starch isolated from normal and waxy wheat

The effects of protein removal on the physicochemical and structural properties of normal and waxy wheat and their A- and B-type granule fractions were investigated. No evident changes were observed in the morphological, birefringence pattern and X-ray diffraction pattern after treatment, but there was evidence showing that the relative crystallinity, swelling power and percentage syneresis of all samples were significant increased. Protein removal treatment increased the peak, setback, final viscosity, breakdown viscosity of normal and waxy native wheat starch, and their A- and B-type starch granule fractions, whereas it decreased the pasting temperature, peak time and trough viscosity. Meanwhile, the thermal transition temperatures (To, Tp, Tc) and gelatinization temperature range (ΔTr) of normal and waxy wheat and their isolated A- and B-type granules were increased, but the enthalpy decrease slightly. The different genetic factors and amylose content in normal and waxy wheat starch and their A- and B-type wheat starch granules fractions were related to the different physicochemical and structural characteristics of those starches.

Physicochemical and rheological properties of starch and flour from different durum wheat varieties and their relationships with noodle quality

Starch and flour properties of different Indian durum wheat varieties were evaluated and related to noodle-making properties. Flours were evaluated for pasting properties, protein characteristics (extractable as well as unextractable monomeric and polymeric proteins) and dough rheology (farinographic properties), while starches were evaluated for granule size, thermal, pasting, and rheological properties. Flour peak and final viscosities related negatively to the proportion of monomeric proteins but positively to that of polymeric proteins whereas opposite relations were observed for dough rheological properties (dough-development time and stability). Starches from varieties with higher proportion of large granules showed the presence of less stable amylose-lipids and had more swelling power, peak viscosity and breakdown viscosity than those with greater proportion of small granules. Noodle-cooking time related positively to the proportion of monomeric proteins and starch gelatinization temperatures but negatively to that of polymeric proteins and amylose content. Varieties with more proteins resulted in firmer noodles. Noodle-cohesiveness related positively to the proportion of polymeric proteins and amylose-lipids complexes whereas springiness correlated negatively to amylose content and retrogradation tendency of starches.

Preparation and characterization of slow-release fertilizer encapsulated by starch-based superabsorbent polymer

To enhance the effectiveness of fertilizers, a novel double-coated slow-release fertilizer was developed using ethyl cellulose (EC) as inner coating and starch-based superabsorbent polymer (starch-SAP) as outer coating. For starch-SAPs synthesized by a twin-roll mixer using starches from three botanical origins, a reduced grid size and an increased fractal gel size on nano-scale (i.e., increased stretch of 3D network) contributed to increasing the water absorbing capacity with a reduced absorbing rate and thus improving the slow-release property of fertilizer. The fertilizer particles coated with starch-SAP displayed well slow-release behaviors. In soil, compared to urea particles without and with EC coating, the particles further coated with starch-SAP showed reduced nitrogen release rate, and in particular, those with potato starch-SAP coating exhibited a steady release behavior for a period longer than 96h. Therefore, this work has demonstrated the potential of this new slow-release fertilizer system for improving the effectiveness of fertilizers.