Effect Of Amylose Content Research Articles

Impact of Starch Concentration on the Pasting and Rheological Properties of Gluten-Free Gels. Effects of Amylose Content and Thermal and Hydration Properties.

The pasting and rheological properties of starch gels from different botanical origins have been widely used to evaluate the application of these starches in pharmaceutical and food products. However, the ways in which these properties are modified by starch concentration and their dependence on amylose content and thermal and hydration properties have not been adequately established so far. An exhaustive study of the pasting and rheological properties of starch gels (maize and rice (normal and waxy in both cases), wheat, potato, and tapioca) at concentrations of 6.4, 7.8, 9.2, 10.6, and 11.9 g/100 g was performed. The results were evaluated in terms of a potential equation fit between each parameter and each gel concentration. The parameters determined for the gels at the studied concentrations were correlated with the hydration properties and thermal properties by applying principal component analysis (PCA). Wheat starch, followed by normal maize and normal rice starches, presented a greater capacity to modulate their gels' pasting and viscoelastic properties via their concentration in water. On the contrary, the characteristics of waxy rice and maize, potato, and tapioca starches were barely modified by concentration in pasting assays, but the gels of potato and tapioca showed noticeable changes in their viscoelastic properties as functions of concentration. In the PCA plot, the non-waxy cereal samples (wheat, normal maize, and normal rice) were located close to each other. Wheat starch gels were the most dispersed on the graph, which is consistent with the high dependence on the concentration of the gel shown in most of the studied parameters. The waxy starches had close positions not too distant from those of the tapioca and potato samples and with little influence from amylose concentration. The potato and tapioca samples were close to the vectors of the crossover point in rheology and peak viscosity in their pasting properties. The knowledge gained from this work allows a better understanding of the effects of starch concentration on food formulations.

Effects of primary, secondary and tertiary structures on functional properties of thermoplastic starch biopolymer blend films

To better understand the correlation between structure and properties in thermoplastic starch biopolymer blend films, the effects of amylose content, chain length distribution of amylopectin and molecular orientation of thermoplastic sweet potato starch (TSPS) and thermoplastic pea starch (TPES) on microstructure and functional properties of thermoplastic starch biopolymer blend films were studied. After thermoplastic extrusion, the amylose contents of TSPS and TPES decreased by 16.10 % and 13.13 %, respectively. The proportion of the chains with the degree of polymerization between 9 and 24 of amylopectin in TSPS and TPES increased from 67.61 % to 69.50 %, and from 69.51 % to 71.06 %, respectively. As a result, the degree of crystallinity and molecular orientation of TSPS and TPES films increased as compared to sweet potato starch and pea starch films. The thermoplastic starch biopolymer blend films possessed a more homogeneous and compacter network. The tensile strength and water resistance of thermoplastic starch biopolymer blend films increased significantly, whereas thickness and elongation at break of thermoplastic starch biopolymer blend films decreased significantly.

Relationship among Extrusion Conditions, Cell Morphology, and Properties of Starch‐Based Foams—A Review

AbstractEnvironmental impact concern of conventional polymer foams has attracted considerable interest for the development of natural‐based polymer foams. Starch is a biopolymer that is gaining acceptability due to its renewability, availability, environmental biodegradation, and low cost. Extrusion is particularly desirable to produce starch‐based foams because it can produce a homogeneous mixing, high heat transfer, high pressure, reduction of the residence time, and low production costs. This review explains the transformation of starch during the foam processing and their relationship with extrusion conditions such as water content, barrel temperature, screw configuration and speed, die temperature, and die dimensions and how all these factors impact on the cell morphology, apparent density, expansion ratio, and final properties of starch‐based foams. The strategies to reduce water sensitivity are described, as well as the effect of amylose content and the addition of additives to improve the starch‐based foams performance as alternative for expanded polystyrene. The extrusion processing conditions can be controlled to obtain the desirable properties for specific applications such as cushioning, packaging, and loose‐fill, among others. Also, a brief look at the starch‐based foams trends, challenges, and perspectives are also discussed.

Generation of porous starch beads via a 3D food printer: The effects of amylose content and drying technique

A new approach via extrusion-based 3D food printing (3DP) was developed to fabricate porous spherical beads from corn starches with different amylose contents (i.e., 25, 55, and 72 %). The effects of amylose content and drying method, i.e., freeze-drying and supercritical carbon dioxide (SC-CO2), on the structural properties of the starch beads were investigated. The shape and size of the 3D-printed beads highly depended on the starches' amylose content as it affected the rheological properties of the inks. The smallest 3D-printed bead size was ∼980 μm generated from high amylose (72 %) corn starch. 3DP of starch with high amylose content along with SC-CO2 drying resulted in starch beads with superior properties. The SC-CO2-dried beads showed a significantly higher surface area (175 m2/g) than the freeze-dried ones (<1 m2/g).

Effect of amylose content on the preparation for carboxymethyl starch/pullulan electrospun nanofibers and their properties as encapsulants of thymol

We proposed a green approach for the preparation of Carboxymethyl starches (CM-starches)/pullulan (PUL) nanofibers and explored their potential properties as encapsulates of thymol. CM-starches from high-amylose (CM-HAS), normal (CM-NCS), and high-amylopectin corn starch (CM-WCS) were synthesized and studied for their spinnability, yet non-fibers could be obtained from these CM-starches. The 20% of PUL was further used to obtain the series of CM-starches/PUL nanofibers from varying CM-starches concentrations. Amylose molecule with efficient molecular entanglement as well as its good solution properties was proved to enhance the electrospinning process with the PUL. Furthermore, the pre-complex of CM-starches-thymol was incorporated in PUL nanofibers using the electrospinning technique. The thymol was successfully encapsulated in nanofibers with a bead-like and increased diameter compared to the morphology of nanofibers without thymol. The pre-complex of CM-HAS-thymol provided a high encapsulation efficiency (EE, 96.59%) for thymol in PUL nanofibers. The inclusion complexation also provided enhancement of thermal stability for thymol and PUL nanofibers. Therefore, the designed nanofibers with thermal stability, degradability, and antibacterial properties have the capacity to be used in food applications.

Effect of Amylose Content on the Formation and Physicochemical Properties of Starch-Fatty Acid Complex

Effect of Amylose Content on the Formation and Physicochemical Properties of Starch-Fatty Acid Complex

A stretchable, compressible and anti‐freezing ionic gel based on a natural deep eutectic solvent applied as a strain sensor

AbstractGlycerin (Gly), a common by‐product in petrochemical industry, is used as hydrogen bond donor. Green organic choline chloride (ChCl) as hydrogen bond acceptor. Natural deep eutectic solvent (NDES) can be prepared with Gly and ChCl. Subsequently, a starch/NDES ionic gel is prepared by in situ free radical polymerization of acrylamide monomer in NDES with starch as the reinforcement. The effects of amylose content in starch and starch addition amount on mechanical properties of ionic gel are analyzed. The results show that starch could be partially dissolved and dispersed in NDES. Compared with the tensile strength of pure NDES gel (about 15 kPa), the tensile strength of starch/NDES ionic gel is increased by 6 times to 90 kPa. It shows good self‐recovery performance after 20 compression cycles. Starch/NDES ionic gel has good thermal stability and frost resistance. In addition, CS4 starch/NDES ionic gel has the highest conductivity. At the same time, starch/NDES ionic gel has been successfully applied to monitor grasping motion of hand, which has the potential of strain sensor. It provides a new green method for the design of electronic products such as electronic skin.

Effect of amylose content in rice flour on batter rheology and bread baking quality

The effect of amylose content in rice batter without wheat on the baking quality and rheological property of rice bread was assessed. Bread was made with waxy and non‐waxy rice flours of similar amylopectin structure at various mixing ratios. The quality of rice bread was evaluated by the expansion ratio. The use of rice flours with similar amylopectin structure controls for the effect of differences in amylopectin structure caused by mixing different rice types. The expansion ratio of bread increased in a rice flour amylose content‐dependent manner. Rheological data showed that high viscosity batters maintained the foam structure generated during proofing, which was related to the high amylose content of the rice flour. An iodine coloration experiment confirmed that the origin of the high viscosity of high amylose rice batters was the elution of amylose into the water surrounding the rice particles in the batter. PRACTICAL APPLICATIONS: In this study, rice bread was made without additives. The batter was made by mixing waxy and non‐waxy rice flours. Storage modulus of the batter was affected by alterations in the mixing ratio of rice flours. Storage modulus of the batter showed a tendency to increase as the ratio of non‐waxy rice increased. The use of high amylose rice flours allowed for the rice batter to be proofed and processed as bread. Practical application of this study is the development of various gluten‐free foods such as bread, pasta, and pizza using rice flour without wheat.

Catalyst-free esterification of high amylose starch with maleic anhydride in 1-butyl-3-methylimidazolium chloride: The effect of amylose content on the degree of MA substitution

The limited reactivity of starch towards maleic anhydride (MA) affords maleate with a low degree of MA substitutions (CC and COOH groups). In this study, we investigated the relationship between the starch structure, controlled by its amylose (AM)/amylopectin (AP) ratio, and the DS of starch maleates using C4[mim]Cl as the recyclable media, and catalyst. The results indicated that starches with varying AM/AP ratio produced maleates with comparable CC groups (DSNMR = 0.06–0.07). Following dissolution, the high amylose (DStitration = 1.17, yield = 69.2 %) and regular starches (DStitration = 1.17; yield = 59.3 %) produced high DStitration maleates (COOH groups) at MA/AGU ratio of 12:1 (80 °C, 10 min). Comparatively, DStitration value of waxy starch maleates (DStitration = 0.88, yield = 59.3 %) was lower than AM-based starches, possibly due to the crosslinking tendency of AP branches consisting of carboxylic end-groups. Interestingly, DStitration value for EHCS (1.17) ranged between its bulk (DSNMR: 0.06) and surface distribution of MA (DSSXPS 1.7); therefore, we considered it reliable for future reference.

Effect of Amylose Content and Molecular Structural Property of the Starches from Different Rice Cultivars on Amylose-Lipid Complex Formation with Various Emulsifiers

Effect of Amylose Content and Molecular Structural Property of the Starches from Different Rice Cultivars on Amylose-Lipid Complex Formation with Various Emulsifiers

In vitro digestibility characteristics of octenyl succinic acid (OSA) modified starch with different amylose content

The effect of amylose content in the in vitro digestibility of non-modified and OSA-modified corn starch was studied. Corn starches with different amylose content (waxy, normal and Hylon VII) were treated with 3% OSA solution. In vitro digestibility tests showed that OSA treatment reduced the fraction of fastly digestible starch, an effect that was more pronounced for cooked starch. The amylose content was negatively linked to the decrease of in vitro digestion. HPSEC analysis was conducted to gain insights on the effect of OSA-treatment on in vitro digestibility. The results showed an increase of the molecular weight of starch chains. Besides, the molecular weight increase was similar for amylose and amylopectin fractions. This suggests that OSA could be acting as a cross-linking agent between starch chains, reducing the susceptibility to amylolysis. Overall, OSA treatment induced the formation of more complex starch chains, offering more resistance for amylolytic reactions.

Effect of amylose content in morphological, functional and emulsification properties of OSA modified corn starch

Octenyl succinic starch esters were prepared from three corn starches with different amylose content; namely, waxy (5.43%), normal (25.16%) and Hylon VII (65.84%). The degree of substitution varies from 0.0103 for waxy starch to 0.0125 for Hylon VII, meaning that the degree of substitution is positively correlated with the amylose content. Scanning electron microscopy images showed that the esterification reaction affected only the granule surface while leaving the integrity of the granules. Solubility and water retention capacity were increased with the OSA modification, with the effect more pronounced for higher amylose contents. X-ray analysis revealed that the crystallinity type was not affected by esterification. FTIR analysis corroborated the changes in the hydrated and ordered structures of starch granules. Emulsification tests showed that octenyl succinic starch ester was an effective emulsifier for stabilization of oil-in-water emulsions. In particular waxy and Hylon VII starches induced high stabilization degrees as revealed by long-term stability of oil-in-water emulsions.

Effects of amylose content and enzymatic debranching on the properties of maize starch-glycerol monolaurate complexes

The effects of pullulanase debranching on the properties of maize starch (waxy, normal and high amylose)-glycerol monolaurate (GML) complexes were studied. Pullulanase pretreatment produced more starch chains with favourable lengths (DP ≥ 25) to encourage inclusion complex formation. The debranched starch showed higher amylose content (from 11.2 to 58.6%) than the native starch (from 0.68 to 53.4%). The V-type characteristic diffraction peaks (7.5°, 13.1° and 20.2° 2θ) became more obvious after the starch received the debranching treatment. Thermal properties indicated that the melting enthalpy of the debranched starch-GML complexes (from 6.45 to 10.13 J/g) was higher than those of the untreated complexes (from 0 to 8.91 J/g). The swelling power values and degree of hydrolysis of the starches decreased with the increase in amylose content. In vitro digestibility analysis suggested that the hydrolysis of the starch-GML samples was further restricted by applying the debranching treatment to the starch.

Effects of amylose content on starch-chitosan composite film and its application as a wound dressing

This study analyzed the amylose content of starches and used them to prepare starch–chitosan composite films to assess their potential as wound dressings. Amylose content was 35.3% in potato starch, 30.5% in corn starch, and 9.7% in glutinous rice starch. The glutinous rice starch–chitosan composite (GC) film, which had a lower amylose content, had a coarser surface and exhibited a higher swelling rate, tensile strength, and elongation at break. In in vitro experiments by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay indicated that GC film had greater biocompatibility with mouse fibroblast L929 cells and human keratinocyte HaCaT cells. The results of the enzyme-linked immunosorbent assay indicated that GC film was more capable of alleviating inflammation than other films by preventing RAW264.7 macrophage from secreting cytokines (TNF-α and IL-6). Additionally, it possessed an excellent coagulation rate. Briefly, the GC film with a lower amylose content is a suitable material for wound dressing.

Effect of amylose content and chemical modification of cassava starch on the microencapsulation of Lactobacillus pentosus

This study aimed to assess the potential of two types of cassava starch with different amylose content (normal and waxy) for the encapsulation of Lactobacillus pentosus. These two cassava starches were modified via acid hydrolysis, phosphatized, and succinated, and evaluated as material for the encapsulation after administering the following four treatments for each type of starch: octenylsuccinate (OSA), sodium tripolyphosphate salt (TPS), 75% OSA/25% TPS, and 25% OSA/75% TPS. Optimal conditions were established for hydrolysis (2.15 M HCl for both starches; 4.56 h for waxy cassava starch [WCS] and 2.44 h for normal cassava starch [NCS]), and the solubility index of the modified starches was significantly increased (p ≤ 0.05) relative to their native and hydrolyzed forms in terms of the morphology of the starch granules; this was affected owing to chemical modification. Together with chemical modifications, amylose content and solubility index were the primary factors influencing the encapsulation. The highest percentage of Encapsulation Efficiency (EE) was achieved using 75% OSA/25% TPS-NCS (93.72%) and TPS-WCS (99.22%). In these mixtures, a synergistic effect was observed between the modified starches, thereby enhancing the (EE); however, the phosphatized starches yielded optimal microencapsulation.

Altering starch branching enzymes in wheat generates high-amylose starch with novel molecular structure and functional properties

Starch that escapes intestinal digestion (resistant starch, RS) is non-glycaemic and considered as dietary fibre. In planta increase of amylose content is a promising approach to make starch resistant to enzyme digestion. Compared to maize, little is known on the effect of amylose content at different length scales of high-amylose wheat (HAW) starch structure and properties. A range of starches with 37%–93% apparent amylose content (AM) were isolated from high-amylose bread wheat produced through non-transgenic breeding altering starch branching enzymes (SBE IIa and IIb). Compared to mutations only in SBEIIa, mutations of both SBE IIa and IIb resulted in higher amylose content with significantly increased proportion of long amylopectin chains (degree of polymerization ≳ 20) and amylose chains. The modified starch molecular structure has significant correlations with starch supramolecular structure and functionality. Compared with wild-type starch, HAW starches showed distinct granular morphology and crystalline pattern with a higher fraction of B-type and V-type polymorph (amylose complex). The peak temperature (Tp) was higher but the onset temperature (To) of gelatinization was not greatly raised (<3 °C) by the mutations. Pasting behaviour of HAW starches (AM<50%) remained similar to wild type, but was greatly reduced at higher AM levels. The data suggest that, depending on food processing condition requirements, different functional and RS properties can be selected based on wheat starch AM content.

Hexamethyldisiloxane cold plasma treatment and amylose content determine the structural, barrier and mechanical properties of starch-based films

In this study, the effect of amylose content and cold plasma treatment on starch films properties was investigated. Films from normal (30%) and high amylose (50 and 70%) starches were subjected to hexamethyldisiloxane (HMDSO) cold plasma treatment. Morphological, structural, mechanical and barrier properties of the films were evaluated. The amount of remnant starch granules (RSG) in the films depended on the amylose content and on the gelatinization extent of the starch. This behavior was corroborated on the films from starch with 50% amylose, where the loss of RSG resulted in poor barrier properties and high hydrophilicity. Moreover, HMDSO cold plasma treatment incorporated methyl groups improving the hydrophobic properties and favored the helix ordering of the starch components resulting in a limited water-film interaction. Furthermore, the simultaneous effect of HMDSO coating and the ordering of the structures reinforced the surface of the films, improving the mechanical properties.

혼합쌀가루로 조절한 아밀로스 함량이 글루텐 프리 쌀 컵케이크의 품질특성에 미치는 영향

혼합쌀가루로 조절한 아밀로스 함량이 글루텐 프리 쌀 컵케이크의 품질특성에 미치는 영향

Effect of Amylose Content on the Physicochemical Properties of Proso Millet Starch

The influence of amylose content (AC) on gel texture, thermal, pasting, rheological and morphologic properties, short-range order, X-ray diffraction pattern, solubility and swelling power of starches from nine proso millet cultivars was investigated. The solubility, swelling power, conclusion gelatinization temperature (Tc), gelatinization temperature range (Tc-To), gelatinization enthalpy (ΔH) and cohesiveness showed a negative correlation to the AC of millet starch. Whereas the pasting temperature (PT), peak viscosity (PV), trough viscosity (TV), final viscosity (FV), setback value (SB), gel hardness, and chewiness showed a positive correlation to the AC of millet starch. The R1047/1022 values of starches ranged in 0.7−0.9, and all starches showed similar morphology features (irregular, polygonal, and spherical shape) and crystal type, which showed no correlation to the AC.

The effect of amylose content and level of oxidation on the structural changes of acetylated corn starch and generation of free radicals

This study was aimed at determining the effect of starch oxidation on its acetylation, structure of starch granules, and generation of free radicals. Corn and waxy corn starches were oxidised by NaClO applied in doses of 10, 20, and 30g Cl/kg of starch, and then acetylated using acetic acid anhydride. The carboxyl, carbonyl, acetyl groups were determined in modified starches. Structural properties of starch granules were evaluated based on molecular weight distribution, gelatinisation, crystallinity, specific surface, intrinsic viscosity. EPR measurements were carried out to establish starch susceptibility to UV irradiation induced generation of free radicals. It was found that the number of carbon centered radicals was dependent on the kind of starch and its chemical modification. Study results allowed concluding that the applied modifications contributed to significant changes in starch granules that were determined not only by the amylose content of starch but also by the degree of its oxidation.