Formation Of Amylose Research Articles

High pressure processing manipulated buckwheat antioxidant activity, anti-adipogenic properties and starch digestibility

Effect of high pressure processing (HPP) on buckwheat nutritional properties is investigated in this study. The results indicated that the digestion of buckwheat starches of untreated and HPP treated at room temperature (RT) showed an “internal corrosion” pattern. However, an “exocorrosion” digestion behavior was observed for the starches of HPP treated sample at 45 °C, which might be due to the formation of amylose–lipid complexes during the process as revealed by X-ray diffraction (XRD). HPP treatment at 45 °C increased the antioxidant activity of the buckwheat as measured using 1,1′-diphenyl-2-picrylhydrazylvalue (DPPH) and iron chelating capacity (ICC) compared to untreated sample (P < 0.05), which might be associated with the release of bound phenolic compounds. More importantly, this is the first study to investigate the ability of buckwheat extract for inhibiting the formation of fat droplets using a C3H10T1/2 mesenchymal stem cell line, and found that the extract of buckwheat after HPP treatment at 45 °C demonstrated significant anti-adipogenic effects. This study suggested the HPP treatment at an increased temperature (45 °C) achieved a better nutritional value of the buckwheat than both untreated and treated at RT.

Changes in wheat (Triticum aestivum L.) flour pasting characteristics as a result of storage and their underlying mechanisms

White wheat flour of a high and a low protein cultivar were stored at 25 °C for 84 days to study age-related changes in flour components and pasting properties. Both cultivars showed similar increases in free fatty acid contents and slight but significant decreases in extractable thiol contents. Rapid Visco Analyser peak, minimal and final viscosities as well as breakdown and setback readings of the high protein flour increased rather gradually along the storage period, while the low protein flour showed more pronounced increases of pasting profiles during the first 21 days of storage. Flour functionality is co-determined by changes in extractable thiol contents during flour storage pointing to their oxidation and the release of free fatty acids which results in additional formation of amylose–lipid complexes and additional substrate for lipoxygenase action which can lead to more extensive co-oxidation of gluten, thereby influencing rheological properties.

Effect of fatty acids on functional properties of normal wheat and waxy wheat starches: A structural basis

The effects of three saturated fatty acids on functional properties of normal wheat and waxy wheat starches were investigated. The complexing index (CI) of normal wheat starch–fatty acid complexes decreased with increasing carbon chain length. In contrast, waxy wheat starch–fatty acid complexes presented much lower CI. V-type crystalline polymorphs were formed between normal wheat starch and three fatty acids, with shorter chain fatty acids producing more crystalline structure. FTIR and Raman spectroscopy presented the similar results with XRD. The formation of amylose–fatty acid complex inhibited granule swelling, gelatinization progression, retrogradation and pasting development of normal wheat starch, with longer chain fatty acids showing greater inhibition. Amylopectin can also form complexes with fatty acids, but the amount of complex was too little to be detected by XRD, FTIR, Raman and DSC. As a consequence, small changes were observed in the functional properties of waxy wheat starch with the addition of fatty acids.

Rheological properties of wheat starch influenced by amylose–lysophosphatidylcholine complexation at different gelation phases

Amylose is able to form helical inclusion complexes with lysophosphatidylcholine (LPC). This complexation influences the functional and rheological properties of wheat starch; however it is well known that the formation of these complexes lead the starchy systems to a slower enzymatic hydrolysis. Based on this, to benefit from both the structuring properties of starch and also lower digestibility of the inclusion complexes, the objective of this study is the formation of amylose–LPC inclusion complexes while developing a firm network providing the desired functional properties in a starchy system. To investigate the influence of amylose–LPC complex formation at different stages of starch gelation on the viscosity behavior of wheat starch, 3% (w/w) LPC was added at three different points of the viscosity profile, obtained by rapid visco analyzer (RVA). LPC addition at all points affected the gelation behavior of wheat starch as compared with the reference. LPC addition at half-peak and peak of the viscosity profile resulted in a viscosity increase during cooling. Measuring the dynamic rheological properties of the freshly prepared gelatinized samples showed a decrease of storage modulus (G′) and loss modulus (G″) in the presence of LPC. During storage, in the presence of LPC, a lower elasticity was observed which indicates a lower rate of amylose retrogradation due to complexation with LPC.

Hydrolysis process of normal rice starch by 1-butanol–hydrochloric acid

The aim of this study was to examine 1-buatnol–hydrochloric acid (1-butanol–HCl) hydrolysis process of starch. Normal rice starch was hydrolyzed by 0.36% HCl in anhydrous 1-butanol at 40 °C from 4 h to 7 days. The changes in starch granule, crystalline, and molecular weight during the 1-butanol–HCl hydrolysis were determined using SEM, particle size analyzer, XRD, HPSEC–MALLS–RI, and iodine staining. SEM and particle size analyzer analysis showed that the granule morphology significantly changed and the granule size decreased from 5.47 μm to 5.07 μm after the hydrolysis by 1-butanol–HCl for 7 days. XRD results indicated that amorphous areas of normal rice starch were firstly hydrolyzed followed by the ordered areas during 1-butanol–HCl hydrolysis. The peak (2θ) of V-type crystallinity was detected at around 20° in the XRD curves of 1-butanol–HCl-hydrolyzed starches. This peak confirmed the formation of amylose–1-butanol complex. HPSEC–MALLS–RI and iodine staining analysis demonstrated that the weight-average molecular weight of normal rice starch sharply decreased from 2.4 × 107 Da to 4.9 × 105 Da after 1-butanol–HCl hydrolysis for 4 h, then gradually decreased, and finally stabilized at about 2.6 × 104 Da after hydrolysis for 4 days. These results suggest that the attack of 1-butanol–HCl on normal rice starch preferentially occurred in the amylopectin molecules of amorphous areas.

Effect of infrared heating on the physicochemical properties of common bean (Phaseolus vulgaris L.) flour

The objective of the presented work was to determine the effect of infrared heating on the physicochemical characteristics of Mexican common bean flour. Variety of Pinto Villa beans were used in the present experiment. Infrared heating was fitted at 0, 10, 20 and 40 Hz. Power absorption, relative crystallinity by X-ray diffraction, proximate analysis, water absorption capacity, water absorption index, viscosity, and total, resistant and available starch methods were used to characterize the common bean flour. X-ray diffraction data showed changes in the diffraction patterns attributable to the possible formation of amylose–lipid complex. Water absorption capacity (WAC) and water absorption index (WAI), as well viscosity profiles, were affected by changes in the starch and protein content. Sample with highest power absorbed (20 Hz) show highest values of WAC and WAI and lowest value of viscosity. The content of resistant starch (RS) was highest at medium absorbed power (10 Hz).

Assessing the susceptibility of amylose–lysophosphatidylcholine complexes to amylase by the use of iodine

The formation of amylose–lysophosphatidylcholine (LPC) inclusion complexes renders amylose less susceptible to amylase digestion. In order to better understand this phenomenon on a structural level, the complexation of 9% wheat starch suspensions with 0, 2, 3, and 5% exogenous LPC was developed in RVA. Amylose–LPC inclusion complexes were isolated after 15, 30, 60, 120, and 240 min in vitro digestion of the wheat starch suspensions to quantify the amount of non‐complexed amylose by spectrophotometry. The samples were dissolved in DMSO containing 0.5% LiBr and exposed to iodine. In addition, parts of the digesta were defatted and subjected to the same procedure to elucidate the total amount of amylose that remained undigested. In this way, more insight was obtained into the protective effect of amylose–LPC complex formation on digestion of starch. This study confirms that the amylose susceptibility to amylolysis decreases in the presence of LPC. Higher LPC concentrations not only induced the formation of more amylose inclusion complexes but also resulted in more stable complexes which remained undigested as well as longer amylose chains after enzyme hydrolysis, due to the presence of LPC inside the amylose helix. In addition, a higher melting enthalpy of the amylose–LPC complexes in the digesta demonstrates the protective effect of LPC during enzyme hydrolysis.

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.

Synthesis of Amylose–Polystyrene Inclusion Complexes by a Facile Preparation Route

The formation of amylose-polystyrene inclusion complexes via a novel two-step approach is described. In the first-step, styrene was inserted inside the amylose helical cavity, followed by free radical polymerization in the second step. The inclusion complexes were characterized by attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR), ultraviolet spectroscopy (UV), X-ray diffraction (XRD), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The formation of polystyrene was confirmed by gel permeation chromatography (GPC). The molecular weight of polystyrene can be varied by using amylose bearing different molar masses. The approach described here is general and could be used to synthesize other host-polymer inclusion complexes for which long chains of polymeric guests are difficult to insert into the host cavity.

Effect of extrusion conditions on physicochemical and sensorial properties of corn-broad beans (Vicia faba) spaghetti type pasta

Corn-broad bean spaghetti type pasta was made with a corn/broad bean flour blend in a 70:30 ratio, through an extrusion-cooking process (Brabender 10 DN single-screw extruder with a 3:1 compression ratio). The effect of temperature (T=80, 90 and 100°C) and moisture (M=28%, 31% and 34%) on the extrusion responses (specific consumption of mechanical energy and pressure) and the quality of this pasta-like product (expansion, cooking-related losses, water absorption, firmness and stickiness) was assessed. The structural changes of starch were studied by means of DSC and XRD. The extrusion-cooking process, at M=28% and T=100°C, is appropriate to obtain corn-broad bean spaghetti-type pasta with high protein and dietary fibre content and adequate quality. The cooking characteristics and resistance to overcooking depended on the degree of gelatinisation and formation of amylose–lipid complexes. The critical gelatinisation point was 46.55%; beyond that point, the quality of the product declines.

The anti-staling effect of pre-gelatinized flour and emulsifier in gluten-free bread

The use of gluten-free products is increasing since an increasing number of people (1–2 %) are suffering from Celiac disease and thereby need a gluten-free diet. Gluten-free bread tends to have shorter shelf life and quality compared with white wheat bread. In this study, 3 % (flour basis) of pre-gelatinized oat and barley flour as well as an emulsifier were added to a gluten-free mix to increase the water content by 1.5–2 %, affect the starch retrogradation and the formation of amylose lipid complex. The staling was followed measuring the firmness (texture analyzer), water content and distribution (nuclear magnetic resonance), amylopectin retrogradation and the formation of amylose–lipid complex (differential scanning calorimetry) in order to see the impact of both macroscopic and molecular changes on firmness. Both gluten-free bread and a white wheat bread were used as control loaves. Largest specific volume was found in the gluten-free control. The firmness varied with both the specific volume and the point of measurement. The amount of retrograded amylopectin increased the firmness, although this effect was dependent on the type of bread, in terms of distribution and availability of the water within the system. The proton relaxation time, which was representing movable water, decreased during storage and revealed that both the amylopectin retrogradation and the lipid complex formation were affecting the rigidity of the amorphous domain and not only the crystalline regions. In contrast to the other recipes, the use of emulsifier caused limited retrogradation and a low correlation between the texture properties and time-dependent events.

Starch modification with microbial alpha-glucanotransferase enzymes

Starch is an agricultural raw material used in many food and industrial products. It is present in granules that vary in shape in the form of amylose and amylopectin. Starch-degrading enzymes are used on a large scale in the production of sweeteners (high fructose corn syrup) and concentrated glucose syrups as substrate for the fermentative production of bioethanol and basic chemicals. Over the last two decades α-glucanotransferases (EC 2.4.1.xx), such as branching enzyme (EC 2.4.1.18) and 4-α-glucanotransferase (EC 2.4.1.25), have received considerable attention. These enzymes do not hydrolyze the starch as amylases do. Instead, α-glucanotransferases remodel parts of the amylose and amylopectin molecules by cleaving and reforming α-1,4- and α-1,6-glycosidic bond. Here we review the properties of α-glucanotransferases and discuss the emerging use of these enzymes in the generation of novel starch derivatives.

Investigation on structural and physicochemical modifications of standard maize, waxy maize, wheat and potato starches after DIC treatment

This study reports the impact of the Instantaneous Controlled Pressure Drop (DIC®) treatment on structural, thermal and functional properties of starches from four botanical origins (standard and waxy maize, wheat and potato, SMS, WMS, WTS and PTS respectively). The structural and functional properties of treated starches were studied using differential scanning calorimetry (DSC), wide-angle X-ray diffraction, optical microscopy and rheological measurements. For cereal starches the resulting modifications were almost identical: increase of the gelatinization temperature and decrease of the transition temperature range that were ascribed to enhanced stability (or size) and cohesion (or homogeneity) respectively of starch crystallites. Potato starch exhibited the reverse tendency according to its particular structural organisation. All the starches showed a reduction of the gelatinization enthalpy as the intensity of the processing conditions increased. The DIC® treatment seemed to cause total or partial melting of the less stable starch crystallites at low temperatures. As a result, the gelatinization temperatures (To and Tp) of the DIC-treated starches increased; this could be attributed to the melting of the most stable crystallites which needed higher temperature range. Microscopy observations confirmed the partial or total loss of birefringence of treated starch granules. Relative crystallinity decreased upon DIC® treatment with a larger impact on PTS that became amorphous at 2bar/12min. The transition for SMS and WTS from A to Vh-type X-ray diffraction pattern revealed the formation of amylose–lipid complexes induced by the treatment. The Brabender viscosity of cereal starches treated at low pressure and processing time was higher than the one of native starches and was clearly reduced for higher pressure levels. For PTS the Brabender viscosity dramatically decreased for all DIC® conditions. Rheological properties of treated starches showed the same tendency except the WTS, whose viscosity was reinforced by the hydrothermal treatment at 3bar/0.5min. The study showed that the different responses observed on treated starches were mainly influenced by DIC® processing conditions and by the botanical origin of the starches.

Starch affecting anti-staling agents and their function in freestanding and pan-baked bread

Anti-staling agents with different mechanisms were added to a normal white wheat bread to investigate the relation between bread staling, amylopectin retrogradation and water-related properties (i.e. water content and distribution between crumb and crust). Bread was baked both as pan-baked and freestanding loaves. The anti-staling agents maltogenic α-amylase, distilled monoglyceride and lipase had a direct influence on starch retrogradation, whereas gluten and waxy wheat flour diluted the amylopectin content or changed the ratio between amylose and amylopectin. The degree of staling was measured as the firmness and springiness, together with two new methods, crumbliness and cutability. In addition, the degrees of amylopectin retrogradation and amylose–lipid complex formation were analyzed by differential scanning calorimetry, and the water content, water loss and water migration were measured. The addition of α-amylase improved most staling parameters, although the changes were not as large as expected. Furthermore, monoglyceride and lipase increased the formation of amylose–lipid complexes, but only lipase gave better results regarding the specific volume and firmness. Increased amylose–lipid complex formation was seen to increase water migration from crumb to crust. Adding 10% waxy wheat flour appeared to lead to a slight overall improvement i.e. lower water migration and better cutability. Adding gluten or 3% waxy wheat flour only improved the specific volume. The method of baking the loaves, i.e. freestanding or pan-baked, had a greater influence than the anti-staling agents, which shows that bread quality is not always improved by starch affecting anti-staling agents without process changes.

Thermal characterisation of corn–lentil extruded snacks

The phase transitions of extruded corn–lentil snacks were investigated using different extrusion process conditions, which were feed rate (2.52–6.84 kg/h), extrusion temperature (170–230 °C) and feed moisture content (13–19% wb). Lentil flour–corn flour mixtures were used at ratios ranging from 10–50%. Extrusion temperature, feed rate and feed moisture content decreased the specific mechanical energy during extrusion cooking. The sorption isotherm at room temperature of corn–lentil snacks was described successfully by the GAB model. The glass transition temperature of extrudates (midpoint of the specific heat shift) increased with feed rate, extrusion temperature, and lentil to corn ratio. Water acts as a plasticiser on extrudates, depressing their glass transition temperature. The Gordon-Taylor equation was used for the plasticisation description and had a good fit with the experimental data. Generally, as the moisture content decreased, the sharpness of glass transition also decreased. The formation of amylose–lipid complexes was confirmed by the presence of an endothermic peak.

Formation of Amylose–Poly(tetrahydrofuran) Inclusion Complexes in Ionic Liquid Media

Abstract In this study, we found that amylose–poly(tetrahydrofuran) (PTHF) inclusion complexes were formed when a mixture of amylose with PTHF was stirred in 1-butyl-3-methylimidazolium chloride of an ionic liquid at high temperature under reduced pressure, followed by cooling and precipitation by addition of methanol.

Formation of inclusion complexes of starch with fatty acid esters of bioactive compounds

The formation of amylose, amylopectin, and high amylose maize starch inclusion complexes with ascorbyl palmitate, retinyl palmitate, and phytosterol esters was evaluated. Amylose and high amylose maize starch formed inclusion complexes with the studied fatty acid esters. However, only retinyl palmitate formed a complex with amylopectin sufficient to cause precipitation. In general, ascorbyl palmitate resulted in the highest complexation, followed by retinyl palmitate and phytosterol ester. The presence of native lipids in high amylose maize starch did not inhibit complex formation. On the contrary, native lipids appear to increase the complexation yield and thermal stability of the starch–fatty acid ester inclusion complexes. The results of this study suggest that the formation of starch inclusion complexes with fatty acid esters seems to be limited by the solubility of the compound in the reaction medium and the structure of the molecule forming the ester with the fatty acid.

Preparation of Enzymatically Recyclable Hydrogels Through the Formation of Inclusion Complexes of Amylose in a Vine‐Twining Polymerization

In this paper, we describe the preparation of hydrogels through the formation of an inclusion complex of amylose in a vine-twining polymerization. This is achieved by the phosphorylase-catalyzed polymerization of alpha-D-glucose 1-phosphate from maltoheptaose primer, in the presence of a water-soluble copolymer having hydrophobic graft-chains (poly(acrylic acid sodium salt-graft-delta-valerolactone)). The mixture turns into a gel during the polymerization process. Evaluation of the hydrogels is conducted by shear-viscosity measurements of the products. For the hydrogels with relatively high viscosities, fast relaxation modes of the cooperative diffusions are observed by scanning microscopic light scattering measurements, which indicate the nanometer-size network structures of the hydrogels. In addition, we found that the enzymatic disruption and reproduction of the hydrogels are achieved by the combination of the amylase-catalyzed hydrolysis of the amylose component and the formation of amylose by the phosphorylase-catalyzed polymerization.

Potential interaction between β-cyclodextrin and amylose–lipid complex in retrograded rice starch

The aims of this study were to investigate the interaction between β-cyclodextrin (β-CD) and amylose–lipid complex in retrograded starch and to propose a model related to the interaction for exploring the retardation of β-CD on starch retrogradation. Results obtained from differential scanning calorimetry (DSC) and X-ray diffraction (XRD) showed that β-CD competed with amylose to disrupt the formation of amylose–lipid complex and that a potential amylose–β-CD–lipid inclusion complex was formed in the retrograded starch. The formation of the complex obviously caused the association of starch chains due to the short and fat aggregates observed using atomic force microscopy (AFM). These findings indicated that the formed amylose–β-CD–lipid complex was responsible for the retardation of starch retrogradation.

Effect of β-cyclodextrin on the long-term retrogradation of rice starch

In this study, the impact of the addition of β-cyclodextrin (β-CD) on long-term retrogradation of rice starch was investigated by texture profile analysis (TPA), differential scanning calorimeter (DSC), and X-ray diffraction (XRD). Results showed that the addition of β-CD presented a crucial role in retarding the long-term retrogradation of starch. The present β-CD also significantly decreased crystallization rate (k), and increased avrami exponent (n). The increase in exponent value indicated that the addition of β-CD transformed the nucleation type due to the formation of amylose–lipid-β-CD complex. Further, the presence of β-CD produced an additional peak 5.2 A of the gelatinized gel, and retarded crystalline type of the retrograded gel from V- to B-pattern, probably corresponding for the nucleation type transformation.