Waxy Starch Research Articles

Effect of high hydrostatic pressure (HHP) on slowly digestible properties of rice starches

The slowly digestible properties of high hydrostatic pressure (HHP)-gelatinized non-waxy and waxy rice starches during the retrogradation were evaluated in this study. The results show that slowly digestible starch (SDS) was observed at a higher percentage in HHP-gelatinized, non-waxy and waxy rice starches than in heat-gelatinized starches, after retrogradation for 7days. The HHP treatment significantly reduced the enthalpy change of starch retrogradation and retarded the freezable water transformation into unfreezable water during retrogradation. This indicated that the SDS percentage was not positively correlated to the retrogradation degree of starch. Furthermore, X-ray diffraction (XRD) data revealed that the HHP treatment decreased the perfect crystallites of the 7day-retrograded. Non-waxy and waxy starches from 19.5% to 12.1% and 15.7% to 11.4%, while increased imperfect crystallites from 26.4% to 30.7% and 28.6% to 31.3%, respectively. These findings suggest that the higher SDS percentage can be attributed to the formation of less perfect crystallites and more imperfect crystallites during the HHP and retrogradation treatments.

Effects of amylose content on property and microstructure of starch-graft-sodium acrylate copolymers

Starch-graft-sodium acrylate (St-g-SA) copolymers were synthesized with ammonium persulfate as an initiator. This work focused on the effects of amylose content of corn starch on the water absorbent capacity and microstructure of the St-g-SA copolymers. The water absorbent capacity of waxy, maize and high amylose St-g-SA copolymers was 1800g/g, 1300g/g and 1100g/g respectively. The grafted copolymers were characterized by FTIR and solid state 13C NMR confirming that the graft reaction had taken place between sodium acrylate and corn starch. The surfaces and cross sections of St-g-SA copolymers were observed by SEM. Incomplete gelatinized starch aggregates increased with increasing amylose content on surfaces and cross sections of copolymers, which accorded with the water absorbent capacity and grafting ratio. DMTA results showed that the waxy St-g-SA copolymer had the highest transition temperature which indicated waxy starch had high grafting ratio.

Molecular characterisation of waxy corn and barley starches in different solvent systems as revealed by MALLS

The effect of different dissolution procedures on molecular characteristics of waxy starches from corn and barley were evaluated using a MALLS (batch-mode) detector, principally to understand the role played by different solvents. Starches were dissolved in aqueous solutions of: (1) 90% DMSO, (2) 2M KOH and (3) 90% DMSO/2M KOH, and stored for 15days at ∼22°C with shaking. Weight-average molecular weight (Mw) and z-average radius of gyration (Rz) were determined at intervals ranging from 0 to 15days. Regardless of starch source and dissolution procedures, Mw and Rz of amylopectin (AP) decreased with increasing storage time. Decrease in Mw followed the order: 90% DMSO>2M KOH>90% DMSO/2M KOH. However, decrease in Rz followed the order: 2M KOH>90% DMSO/2M KOH>90% DMSO. The study indicated that starch solubilisation in 90% DMSO/2M KOH may be a reasonable method for molecular characterisation with less AP degradation.

Rheological properties of reactive extrusion modified waxy starch and waxy starch-polyacrylamide copolymer gels

The rheological properties of modified waxy starch and waxy starch–polyacrylamide graft copolymers prepared by reactive extrusion were investigated. Both materials can absorb huge amount of water and form gels. The modified waxy starch and waxy starch–polyacrylamide graft copolymer gels all exhibited viscoelastic solid properties. The waxy starch–polyacrylamide graft copolymer gels with the concentration ≤10% showed weaker viscoelastic behaviors than those of the same concentrations of modified waxy starch gels. However, at concentration ≥11.25%, the waxy starch–polyacrylamide graft copolymer gels displayed much stronger viscoelastic properties than those of the same concentrations of modified waxy starch gels. The analysis of modulus and concentration dependence and stress relaxation measurements indicated that both modified waxy starch and waxy starch–polyacrylamide graft copolymer gels were physical gels meaning the cross-linkers between the molecules were physical junctions. The nonlinear steady shearing rheological properties studies indicated that both modified waxy starch and waxy starch–polyacrylamide graft copolymer gels exhibited shear thinning behavior, which can be well fitted with the power law constitutive equation. The function and behavior of the modified waxy starch and waxy starch–polyacrylamide graft copolymer gels suggest that these starch-based biomaterials should be potential candidates for applications in cosmetic gels, wound skin care materials, and agricultural products.

Characteristics of Modern Triticale Quality: The Relationship Between Carbohydrate Properties, α‐Amylase Activity, and Falling Number

ABSTRACTTriticale is a high‐yielding cereal crop with potential to increase grain production for human consumption over the coming decades. Minimal targeted selection has been conducted to produce cultivars with α‐amylase, amylose, and nonstarch polysaccharide (NSP) content appropriate for a milling market. Nevertheless, genotypic variability exists. Standard quality screening methods used for wheat, including pasting properties, falling number, and quantification of α‐amylase activity were employed to assess the environmental and genotypic variability among modern triticale cultivars and to investigate the suitability of these tests for triticale. Samples of 11 triticale lines from four environments were compared with five wheat cultivars bred for various end uses. Triticale exhibited a greater range than wheat for most tested variables, and the ranges usually overlapped. Triticale exhibited higher NSP content, generally equivalent pasting properties, higher α‐amylase activity, and lower falling number on average compared with wheat checks. However, low falling number was not indicative of high α‐amylase activity; the relationship with NSP level and other factors is discussed, and caution is recommended for interpretation of previous research. Three cultivars with equivalent α‐amylase activity to wheat and two with partially waxy starch were identified. These findings have great significance for research and the emerging triticale milling market.

Effect of Waxy Maize-Derived Hydroxyethyl Starch 130/0.4 on Renal Function in Surgical Patients

Background:The aim of this meta-analysis was to evaluate renal safety with the active substance of the latest generation of waxy maize-derived hydroxyethyl starch in surgical patients. The authors focused on prospective, randomized, controlled studies that documented clinically relevant variables wi

Application of marker‐assisted selection and genome‐wide association scanning to the development of winter food barley germplasm resources

AbstractBarley (Hordeum vulgare) is an important component of heart‐healthy whole grain diets because it contains β‐glucan. All current US barley varieties with high β‐glucan are spring habit and have waxy starch. Winter varieties have agronomic advantages but require low‐temperature tolerance (LTT). Vernalization sensitivity (VS) is associated with higher levels of LTT. To rapidly develop fall‐sown varieties with LTT and higher grain β‐glucan, we therefore used marker‐assisted selection (MAS) at the WX and VRN‐H2 loci. The MAS‐derived lines, together with unrelated non‐waxy germplasm developed via phenotypic selection (PS), were used for a genome‐wide association scan (GWAS). The panel was phenotyped for grain β‐glucan, LTT and VS. It was genotyped with 3072 single‐nucleotide polymorphisms (SNPs) and allele‐specific primers. Marker‐assisted selection fixed target alleles at both loci but only one of the target phenotypes (higher β‐glucan percentage) was achieved. Variation for VS and LTT is attributable to (i) incomplete information about VRN‐H1 at the outset of the project and (ii) unexpected allelic variation at VRN‐H3 with a large effect on VS and LTT.

Assessment of waxy and non-waxy corn and wheat cultivars as starch substrates for ethanol fermentation

AbstractThe amylose/amylopectin ratio in cereal substrates is one of the parameters affecting starch hydrolysis and fermentation process. Waxy (less than 1 mass % of amylose) starch seems to be suitable for improving the fuel ethanol production. The main aim of this paper was to characterize the fermentation performance of corn and wheat waxy and non-waxy cultivars in terms of simultaneous saccharification and fermentation (SSF) as well as of the separated hydrolysis and fermentation (SHF) type. Two corn (waxy and non-waxy) and two wheat (waxy and non-waxy) cultivars were used for the comparison applying separate enzymatic hydrolysis and fermentation. In the SHF process, the glucose content was higher after saccharification in the waxy corn and wheat compared to that in non-waxy corn and wheat. In the SSF of waxy varieties, the glucose content after the pre-saccharification was also higher than in the non-waxy ones. Although the starch content did not vary significantly, differences in the glucose content after saccharification were observed. The ethanol yield obtained after the distillation of mash varied from 229.2–262.3 L per ton for the SHF fermentation, while it was in the range of 311.5–347.9 L per ton for the SSF process.

Effect of granular characteristics on pasting properties of starch blends

Pasting and morphology properties of starch blends composed of waxy (waxy rice and waxy corn) and non-waxy (normal corn, tapioca and potato) starches at various ratios were investigated for elucidating effect of granular characteristics on pasting of blends. Pasting profiles of blends were between those of the component starches alone, while the changes varied with starch source. Results reveal obvious water competition during pasting for blends composed of waxy starch and highly swelling non-waxy (tapioca or potato) starch. On the contrary, starch blends composed of waxy starch and non-waxy (normal corn) starch with restricted swelling showed less water competition during pasting, and the pasting attributes could be estimated from those of the component starches following the mixing ratio. Results indicate that the pasting properties of starch blends composed of waxy and non-waxy starches depend on not only the mixing ratio, but also the granular characteristics of component starch.

Effects of Cooking Methods and Starch Structures on Starch Hydrolysis Rates of Rice

This study aimed to understand effects of different cooking methods, including steamed, pilaf, and traditional stir-fried, on starch hydrolysis rates of rice. Rice grains of 3 varieties, japonica, indica, and waxy, were used for the study. Rice starch was isolated from the grain and characterized. Amylose contents of starches from japonica, indica, and waxy rice were 13.5%, 18.0%, and 0.9%, respectively. The onset gelatinization temperature of indica starch (71.6 °C) was higher than that of the japonica and waxy starch (56.0 and 56.8 °C, respectively). The difference was attributed to longer amylopectin branch chains of the indica starch. Starch hydrolysis rates and resistant starch (RS) contents of the rice varieties differed after they were cooked using different methods. Stir-fried rice displayed the least starch hydrolysis rate followed by pilaf rice and steamed rice for each rice variety. RS contents of freshly steamed japonica, indica, and waxy rice were 0.7%, 6.6%, and 1.3%, respectively; those of rice pilaf were 12.1%, 13.2%, and 3.4%, respectively; and the stir-fried rice displayed the largest RS contents of 15.8%, 16.6%, and 12.1%, respectively. Mechanisms of the large RS contents of the stir-fried rice were studied. With the least starch hydrolysis rate and the largest RS content, stir-fried rice would be a desirable way of preparing rice for food to reduce postprandial blood glucose and insulin responses and to improve colon health of humans.

Characterization of internal structure of maize starch without amylose and amylopectin separation

Normal maize starch was used to characterize the internal structure of starch without separating amylose and amylopectin, and the result was compared with amylose-free waxy maize starch. The clusters in the whole starch were produced by partial hydrolysis using α-amylase of Bacillus amyloliquefaciens, and were subsequently treated with β-amylase to remove the linear amylose and to produce β-limit dextrins of clusters from amylopectin. The clusters were further hydrolyzed extensively with α-amylase to produce building blocks. The compositions of clusters in the form of β-limit dextrins and their building blocks were analyzed by gel-permeation chromatography and high-performance anion-exchange chromatography. The results showed that the structures of clusters and building blocks from whole starch of normal and waxy starches were similar. By number, each cluster contained 9–10 chains and 5–6 building blocks. The inter-block chain length in the clusters of whole starch was around six glucosyl residues. This study explored an alternate procedure to characterize the composition of branches in whole starch without separating amylose and amylopectin components.

In situ study of maize starch gelatinization under ultra-high hydrostatic pressure using X-ray diffraction

The gelatinization of waxy (very low amylose) and high-amylose maize starches by ultra-high hydrostatic pressure (up to 6GPa) was investigated in situ using synchrotron X-ray powder diffraction on samples held in a diamond anvil cell (DAC). The starch pastes, made by mixing starch and water in a 1:1 ratio, were pressurized and measured at room temperature. X-ray diffraction pattern showed that at 2.7GPa waxy starch, which displayed A-type XRD pattern at atmospheric pressure, exhibited a faint B-type-like pattern. The B-type crystalline structures of high-amylose starch were not affected even when 1.5GPa pressure was applied. However, both waxy and high-amylose maize starches can be fully gelatinized at 5.9GPa and 5.1GPa, respectively. In the case of waxy maize starch, upon release of pressure (to atmospheric pressure) crystalline structure appeared as a result of amylopectin aggregation.

Effect of Different Corn Starches on Microstructural, Physical and Sensory Properties of Gluten‐Free White Sauces Formulated with Soy Protein and Inulin

AbstractDifferent corn starches were used to prepare gluten‐free white sauces made with soy protein and inulin. A remarkable different microstructure between sauces made with modified or native starches was observed. The former were characterized by a packed matrix of swollen starch granules, while the latter showed a few starch granule remnants dispersed in a starch polymer–protein–inulin continuous phase. These microstructural differences were related to significant differences (P < 0.05) in the apparent viscosity values observed between sauces made with modified or native starches. Moreover, sauces made with waxy starches exhibited stable apparent viscosity values throughout refrigeration storage. Syneresis was negligible even in sauces made with native starch, proving the high water retention capacity of the soy protein–inulin–starch polymer matrix. In general, sauces made with modified starches had stable color parameters throughout storage and were preferred by consumers, which make them interesting in the development of this type of product.Practical ApplicationsStarches, both native and modified, from several botanical sources have been widely used in food industry to improve the textural properties and stability of sauces during their shelf life. However, new product development is increasingly focused in nutritional aspects due to consumer's demand for healthy food. In this context, the use of corn starches as gluten‐free sources as well as the replacement of fat by inulin and the use of soy protein instead of milk could be interesting in the development of white sauces suitable for consumers with particular nutritional requirements. First, it is necessary to evaluate the structural, physical and sensory properties of these mixtures to select the best formulation for the final product.

Physicochemical and morphological characterization of different starches with variable amylose/amylopectin ratio

Starch-rich raw materials are widely used in the food industry. Their functionality and end-use applications are markedly influenced by starch characteristics. Starches with varying amylose (AM) and amylopectin (AP) content are of particular interest due to their ability to influence and modify the texture, quality and stability of starch-based food products. The present study shows the influence of the AM/AP content on physicochemical and morphological properties of a range of starches (Maize = 3%, 23%, 71%; Potato = 2%, 21%; Wheat = 28; Barley = 3%, 25% AM content w/w of starch).Starches have been analyzed in terms of their chemical composition, water retention capacity, morphological characteristics, and pasting/thermal properties. The changes in starch granule morphology during gelatinization were monitored by confocal laser scanning microscopy (CLSM). The different analysis revealed that waxy-starches (AP>90%) had a high water retention capacity (1.2–1.5 times higher) and developed higher paste viscosities (up to 40% for maize; 43% for barley). The swollen granules were highly susceptible to mechanical breakdown and solubilized faster. Higher AM contents showed inhibition of an extensive granule swelling and lowered the paste viscosity. The exceptional integrity of the high-AM starch even prevented its gelatinization at atmospheric pressure. Significant differences in physicochemical and morphological properties between the starches from regular, high-AM and waxy strains have become evident, no direct relationship between the AM/AP contents and the internal growth ring structures of the starch granules could be identified by CLSM. The waxy starches had a higher gelatinization temperature (up to 2 °C) and enthalpy (up to 20%), which indicates a higher crystalline and molecular order.

Relations between Molecular, Crystalline, and Lamellar Structures of Amylopectin

Chain (branch) length distributions (CLD) from size-exclusion chromatography of a series of waxy starches were parametrized using both an empirical and a biosynthesis-based method and correlated with their crystalline-amorphous lamellar properties obtained from X-ray scattering. Correlations were best seen with the biosynthesis-based parametrization. This showed for the first time that the following links between the CLD and lamellar parameters, the average interlamellar repeat distance and the distribution of these distances, were decreased by an increase in the proportion of very short branches and were increased by an increase in the proportion of intermediate and longer chains; further, the shoulder and linear sections of the CLD were found to affect the lamellar repeat distance and distribution. These effects are rationalized in terms of branch-length effects on the production of crystallites and the presence of portions of longer branches in the amorphous regions.

Genotype diversity in structure of amylopectin of waxy rice and its influence on gelatinization properties

A set of 13 waxy rice genotypes prepared by chemically-induced mutation of non-waxy rice variety TNG67 and 7 waxy rice varieties widely planted in Taiwan were screened for various structural and gelatinization properties of starches. Wide variation on physicochemical properties and molecular structure of amylopectin for the 20 waxy rice starches were obtained and relationship between gelatinization properties and molecular structure of starch were discussed. More attributes on swelling and gelatinization thermal properties, comparing to pasting attributes, showed significant correlation with molecular structure parameters. The swelling and gelatinization thermal properties of waxy rice starch did not show significant correlation with molecular size of amylopectin, while significant correlations were found between the swelling or gelatinization thermal properties and chain length of amylopectin. Results suggest that the swelling and pasting of waxy starch is essentially dominated by granule architecture and is dependent on the interactions among amylopectin chains.

Influence of xanthan transition on the rheological properties of waxy starches

The effects of xanthan gum on the properties of waxy starch systems were investigated with a particular focus on the conformational transition of xanthan. Different types of starches were used in this setup: maize, potato, chemically modified maize and rice. Under dilute conditions, xanthan gum and its transition did not affect the gelatinization of the starches. However, significant effects on the pasting behavior were observed, where the xanthan transition caused a significant reduction of the viscosity. It was demonstrated that xanthan can limit the breakdown of sensitive starch granules and that this effect might be enhanced by the xanthan transition. Flow curves of the cooled pastes showed that granule integrity is a prerequisite for optimal xanthan functionality, but the granule stabilizing effect of xanthan was too limited under these pasting conditions to significantly influence the flow behavior.

Molecular and supra-molecular structure of waxy starches developed from cassava (Manihot esculenta Crantz)

The aim of this work was to characterize the amylopectin of low amylose content cassava starches obtained from transgenesis comparatively with a natural waxy cassava starch (WXN) discovered recently in CIAT (International Center for Tropical Agriculture). Macromolecular features, starch granule morphology, crystallinity and thermal properties of these starches were determined. M¯w of amylopectin from the transgenic varieties are lower than WXN. Branched and debranched chain distributions analyses revealed slight differences in the branching degree and structure of these amylopectins, principally on DP 6–9 and DP>37. For the first time, a deep structural characterization of a series of transgenic lines of waxy cassava was carried out and the link between structural features and the mutated gene expression approached. The transgenesis allows to silenced partially or totally the GBSSI, without changing deeply the starch granule ultrastructure and allows to produce clones with similar amylopectin as parental cassava clone.

Rheological scaling properties of starch solutions in dimethylsulfoxide

Abstract The possibility of scaling viscoelastic properties of starch solutions in relation to biopolymer concentration was presented in this study. An application of this empirical method enabled to widen the observation horizon of viscoelastic properties. It was also determined that the scope of its applicability is limited by amylose content in the solution. In high amylose solutions, for which up to 40% (w/w) concentration was the highest one obtained, calibration caused the formation of master curve in the widest frequency range. Determined values of scaling coefficients aC changed exponentially in starch concentration function in the solution. For waxy starch solutions of maximum concentration equal to 20% (w/w), scaling did not significantly widen the observation window. Based on master curves constructed in such way, continuous relaxation spectra H(λ) were determined using Tikhonov regularisation method. Their structure indicates advantageous of viscous elements in the process of viscoelastic phenomena formation.

Evaluation of alternatives to guar gum as tackifiers for hydromulch and as clumping agents for biodegradable cat litter

Guar gum is currently the principal gum used as a tackifier for hydromulch used in erosion control, and as a clumping agent in biodegradable cat litters. Due to recent severe price increases for guar gum, cheaper alternatives are being investigated. We examined several alternatives, including xanthan gum, plantago gum, methyl cellulose, pectin, lignin, camelina (Camelina sativa L. Crantz) and lesquerella [Lesquerella fendleri (A. Gray) S. Wats.] seedmeals (which both contain polysaccharide gums), waxy corn starch (which lacks amylose), and both high amylose (70% apparent amylose content) and normal (25% apparent amylose content) corn starch–sodium palmitate inclusion complexes produced by steam jet cooking. Plantago and xanthan gums, lignin-CaCl2, camelina and lesquerella seedmeals, and the high amylose starch–sodium palmitate inclusion complex were as effective in resistance to simulated rainfall as guar when used as hydromulch tackifiers at a standard application rate. Methyl cellulose, pectin, waxy starch and the normal corn starch–sodium palmitate inclusion complex had lower rainfall resistance than guar. For cat litter clumping ability, plantago and xanthan gums and methyl cellulose were equal to guar gum at the 2% rate. Pectin and the normal starch–sodium palmitate inclusion complex had acceptable levels of clumping at this rate. Lesquerella seedmeal and the high amylose starch–sodium palmitate inclusion complex had acceptable clumping only at the higher (6%) rate tested but not at the 2% rate. Neither camelina seedmeal nor waxy starch had acceptable clumping values at either rate. These results indicate that several of these materials are potential alternatives to guar as a tackifier for hydromulch and in clumping cat litters, particularly if material costs are significantly lower.