Maize Amylopectin Research Articles

Molecular structure of lotus seed amylopectins and their beta-limit dextrins

Investigation on amylopectin molecular structure is gaining importance for understanding starch property. Lotus seeds are a novel starch source with high apparent amylose content. Current understanding on the molecular structure of amylopectin in lotus seed starch is scarce. This study compared the molecular structure of a range of lotus seed amylopectins with those of maize and potato amylopectins. Internal structures of these amylopectins were compared via investigating the chain length distribution of their β-limit dextrins. The average lengths and molar compositions of unit chains in lotus seed amylopectins and their β-limit dextrins fell generally between those of maize and potato. The average chain lengths of lotus seed, maize, and potato amylopectins were 19.95 (on average), 19.11, and 21.19 glucosyl residues, respectively. Lotus seed amylopectins had higher weight proportion of clustered unsubstituted chains (44.94 % on average) than those of potato (43.99 %) and maize amylopectins (42.95 %). Results of correlation analysis indicated that apparent amylose content of LS was related to structural characteristics of its amylopectin due to the presence of long external chains. The results of this study are of fundamental importance for the utilization of lotus seed starch as a novel starch source.

The anti-retrogradation properties of maize amylopectin treated by being co-crystallized with NaCl

Long-term retrogradation of amylopectin always leads to the quality deterioration of starch-based food. In this paper, the purified maize amylopectin was co-crystallized with NaCl to obtain anti-retrograded amylopectin. The results showed that the retrogradation rate of maize amylopectin dropped directly from 27.92 % to 19.05 % at the conditions of amylopectin: 5 % NaCl (m/v) = 1.7:10, eutectic times 24 h at 4 °C. The co-crystals with a dendritic shape consisted of a center and several large branches and the length of the largest branch reached up to 10,000 μm. The results of the maximum absorbance of iodine-attached amylopectin, molecular weight and chain length distributions showed that hydrolysis and graft of amylopectin happened in the eutectic process. Residues produced by acid hydrolysis linked to the main chains via α-1,6 glycosidic linkage at the late stage of eutectic reaction. The marked signs for single helix of maize amylopectin with Mw >20 × 105 g/mol were the enhancement of weak resonance at 100.0 ppm (104.1, 100.0, 94.6, 82.9 ppm). Single-helix maize amylopectin was more likely to form sharp X-ray diffraction during being dried without gelatinization. The possible mechanism for anti-retrogradation of maize amylopectin by co-crystal treatment was deduced. Co-crystallization with NaCl to produce single-helix amylopectin was a promising strategy to prepare anti-retrogradation amylopectin.

Use of pullulanase as a biocatalyst for starch hydrolysis: Part 1. Study of the effect of pullulanase on maize amylopectin starch

The use of debranching enzymes in starch hydrolysis is a topical direction for obtaining new types of starch products with controlled properties and a potential for the further use. The aim of the work was to study an effect of pullulanase (EC3.2.1.41) on maize amylopectin starch in the native and gelatinized state. The objects of the research were maize amylopectin starch and enzyme preparation Promozyme D6 (Novozymes, Denmark). High-performance liquid chromatography (HPLC) was used to determine the carbohydrate composition of hydrolysates. The mass fraction of reducing substances (RS) was determined by the Lane and Eynon method. A rotational viscometer was used to measure dynamic viscosity of the starch hydrolysis products. It was found that analyzed starch in the native state showed low enzymatic sensitivity to the action of pullulanase with insignificant changes in viscosity, solubility and iodine binding capacity of the samples. Pullulanase showed the highest effect on gelatinized starch during the first eight hours of incubation. After eight hours, the maximum degree of starch hydrolysis by pullulanase at a dose of 10 units/g dry matter (DM) was 4.7% on DM basis, iodine binding capacity of the hydrolysate was D600 = 0.343 (in the control experiment D600 = 0.154), and the viscosity of the hydrolysate decreased from 7887 mPa · s to 4.3 mPa · s. Hydrolysates cooled to 8 °C and held for 20 hours along with hydrolysates that were not cooled showed high susceptibility to attack by glucoamilase (97–98%) at 60 °C and 24 hours of saccharification, which suggested the absence of their resistance to the action of glucoamilase in the conditions of the experiment. The use of pullulanase in dextrinization of the analyzed starch, which was gelatinized and partly hydrolyzed by α-amylase (RS6.1%), enabled obtaining hydrolysates with the mass fraction of reducing substances in a range of 10–24% on DM basis with the process duration of 2 to 24 hours and the enzyme dose of 2–10 units, which contained mainly maltotriose, maltohexose and maltoheptose with their total amount of 45–60% on DM basis. The results indicate a need for further research of the biocatalytic action of pullulanase to develop new methods for enzymatic modification of starch.

Modulating Phenolic Bioaccessibility and Glycemic Response of Starch-Based Foods in Wistar Rats by Physical Complexation between Starch and Phenolic Acid.

This study assessed the impact of caffeic and ferulic acid complexation with maize amylopectin or potato starch on glycemic parameters. In comparison to starch-phenolic mixtures, starch-phenolic complexes resulted in significant modification of phenolic bioaccessibility and cellular uptake (p < 0.05). In addition, glucose release from in vitro digestion of starch was modestly reduced in the complexes compared to native starch alone (21.2-26.8 versus 29.8-30.5 mM). Furthermore, intestinal glucose transport, assessed in Caco-2 cell monolayers, was not affected by the presence of complexes (82.4-124 versus 100% at 90 min). However, a reduced glycemic response was evident in a Wistar rat model, with significant reduction in 240 min of blood glucose area under the curve following oral administration of the potato starch-ferulic acid complex compared to native potato starch (26 170 ± 556 versus 28 951 ± 486 mg min dL-1; p < 0.001). These alterations were attributed to complexation-induced resistant starch formation and phenolic entrapment, providing an alternative mechanistic approach to modulate glycemic properties of starch-based foods.

Starch-phenolic complexes are built on physical CH-π interactions and can persist after hydrothermal treatments altering hydrodynamic radius and digestibility of model starch-based foods

Leveraging phenolic complexation to optimize starch functionality and digestibility is restrained by the obscurity of their physicochemical nature and molecular basis. To define starch-phenolic complexes under hydrothermal treatments, maize amylopectin and potato starch were complexed with caffeic acid, ferulic acid and gallic acid. Starch hydrothermal stability and digestibility were measured by differential scanning calorimeter and Englyst’s method, respectively. While monosaccharide compositions and glycosidic linkages were analyzed by GC–MS, hydrodynamic radius and proton magnetic resonance of gelatinized complexes were measured by dynamic light scattering and NMR respectively. Compared with native starches, starch-phenolic complexes were not chemically modified and had modestly lower estimated glycemic indexes and significantly lower gelatinization temperatures (p < 0.05). Starch-phenolic complexes also had significantly lower levels of phenolic proton intensities and hydrodynamic radii relative to the control starch-phenolic mixtures (p < 0.05). These results suggested that phenolics may complex with starch through non-covalent CH-π bonds along α-(1 → 4) glycosidic chains.

Comparison of molecular structure of oca (Oxalis tuberosa), potato, and maize starches

Oca (Oxalis tuberosa) is an underutilized species and represents a novel starch source. Composition and structure of starches from tubers of two commercial oca varieties grown in New Zealand were compared to those of normal maize and potato starches. The phosphorus content of oca starch was ∼60% of that of potato starch. The amylose content of oca starch (∼21%) was lower than that of maize and potato starches (concanavalin A precipitation method). The fine structure of oca amylopectin was much more similar to that of potato amylopectin than to that of maize amylopectin. Oca amylopectin had a shorter internal chain length and less fingerprint B-chains than potato amylopectin. The two oca starches were structurally and compositionally similar. Oca starch granules had a volume moment mean size of 34.5 μm and B-type polymorph. Comparative analysis suggested that oca starch has the potential to be developed as a novel starch source.

A New Method to Purify Hydroxyl Monascus Red Pigment by Retrogradation of Both Pigments and Maize Amylopectin

In monascus red pigment (MRP) products, there exist many components such as polypeptides, amino acids, polysaccharide, and citrinin (toxin). The existence of those components lowers the purity of pigments and brings a great security problem. Hydroxyl MRP has been found in products of China and other countries. This paper presents a new method to isolate hydroxyl MRP by retrograded maize amylopectin (MA) and proposes the mechanism involved based on investigation of Xray‐diffraction, IR and ¹³C solid NMR spectra. The research results have shown that the optimum retrogradation parameters for purification of hydroxyl MRP are as follows: the ratio of pigments and MA is 1:1, autoclaving temperature 120 °C and time, 20 min, aging temperature 4 °C and time needed, 48 h. Most non‐pigment components without hydroxyls in the samples are dissolved in solution when retrograded MA containing MRP has been hydrolyzed by amylase with only MA and MRP left in the precipitatate. Such precipitation can redissolve in aqueous KOH to open hydrogen bond and the MA in solution can be distilled by ethanol in neutral pH, and then the purified pigments in solution can be concentrated and dried. Every 100 g MA can isolate 68.0 g MRP. The results of IR and ¹³C solid NMR have indicated that hydrogen bonds might form between C7 of pigment and C1 of MA, also, C10 of pigment and C3 or C2 of MA. Retrogradation is surely a simple, inexpensive, and valid method to isolate pigments with hydroxyl groups and citrinin.

Complexation with phenolic acids affect rheological properties and digestibility of potato starch and maize amylopectin

As well-documented inhibitors of starch digestive enzymes, dietary phenolics are less known for the ability to modify starch structures and functionality. This study aimed to characterize changes in starch structures by complexing individual phenolic acids with maize amylopectin and potato starch respectively, and to determine pasting properties and digestibility of the resulting complexes. FTIR-ATR results confirmed (995/1022 and 1047/1022 cm−1/cm−1) reduced crystallinity in short-range order of both starches, which were likely caused by a decrease in moisture content and/or by attenuation of molecular interactions in both crystalline and amorphous lamellas. Measurements of apparent amylose content and amylose leaching discovered formation of amylose-like structures in amylopectin and V-type amylose in potato starch. These structural changes were negatively associated with pasting temperature, peak viscosity, hot paste viscosity and cold paste viscosity. Digestibility was modestly lower for starch-phenolic acid complexes than for native starch and starch-phenolic acids mixtures. More interestingly, a small fraction of phenolic acids remained bound to starch molecules after pasting of starch-phenolic acid complexes, suggesting bound phenolic acids as a potential factor inhibiting starch hydrolysis.

In vitro amylase hydrolysis of amylopectins from cereal starches based on molecular structure of amylopectins

To study the effects of the fine structures of APs on the enzymatic hydrolysis of wheat amylopectin (WA), maize amylopectin (MA) and waxy maize amylopectin (WMA), the relationship between the chain length distributions and enzymatic hydrolysis of amylopectins was established using high-performance anion-exchange chromatography, high performance liquid chromatography and logarithm of slope analysis (LOS). The results showed that WMA possessed a higher numbers of short-chains with a greater branch density, shorter average chain length and interblock chain length of amylopectin compare to WA and MA possessing a comparatively looser molecular structure. WA and MA were digested in two linear phases in the LOS plots, whereas WMA displays single phase. Whether using α-amylase alone (AA), or together with amyloglucosidase (AA/AMG), the k value of MA was slightly higher than that of WA in two-phase process, whereas the k value of WMA is far lower than that of WA and MA. Using AA alone, α-amylase releases very little glucose from WA, MA and WMA, the primary products of α-amylase being G2, G3 and G4. While together with AMG, the release of G1 significantly enhances. Using AA alone or AA/AMG, G6 and G7 from WA, MA and WMA are good hydrolytic substrates eventually reacting to yield G1 and G2 as the incubation time increases.

Effects of oligomeric procyanidins on the retrogradation properties of maize starch with different amylose/amylopectin ratios.

The effect of oligomeric procyanidins (OPCs) on the retrogradation of maize starch with different amylose/amylopectin ratios was investigated. The apparent amylose contents in high-amylose maize (HAM), normal maize (NM), and amylopectin maize (APM) starches are 79.05%, 25.43% and 0%. Structural characterizations of retrograded maize starches in the presence of OPCs were conducted by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR). The results suggest that OPCs inhibit the retrogradation of maize starches in low concentrations (1.5-2.5%) with different inhibitory effects for HAM, NM and APM starches. It may be attributed to the variations on interaction ways and binding capabilities between different types of starches and OPCs. The in vitro enzymatic digestion result indicates HAM starch and OPCs have stronger interactions with the formation of resistant structures. These findings provide a further evidence for exploring the interactions between starches and phenolic compounds.

Synthesis and characterization of enzymatically cross-linked feruloyl amylopectin for curcumin encapsulation

Feruloyl amylopectin (FAP) was synthesized by the N,N′-carbonyldiimidazole (CDI) activation method, and the enzymatically cross-linked feruloyl amylopectin (CL-FAP) was prepared via catalysis of horseradish peroxidase (HRP) with the presence of hydrogen peroxide (H2O2). RP-HPLC-DAD/ESI-TOF-MS measured ferulic acid and its derivatives in FAP and CL-FAP. FAP was primarily composed of two ferulate monomers, while CL-FAP was composed of two ferulate monomers and two ferulate dehydrodimers. The ester formation in the feruloyl group was confirmed by the presence of carbonyl and aromatic CC signal near 1725 (1723) and 1510cm−1 in the FT-IR spectra. X-ray diffraction studies showed that the two modified amylopectins lost the ordered A-type crystalline structure, characteristic of maize amylopectin. The encapsulation capacity of curcumin (ECC) in 1mg/mL CL-FAP microemulsion was measured at 88.13μg/mg by HPLC.

Formation and properties of selected quantum dots in maize amylopectin matrix

CdS, ZnS, Ga2S3, CaS and Cs2S quantum dots (QDs) were generated in the amylopectin (Ap) matrix. They all emitted a light between 460 (ZnS) and 475 (CdS) nm. Sizes of Ga2S3 and CdS QDs were 7–9nm and 5–7nm, respectively. Single ZnS QDs had 6–7nm but they readily aggregated. The CaS and Cs2S appeared mainly as 30–100nm aggregates. There were no significant interactions between QDs and the Ap matrix. Presented method appeared unsuitable for the generation of CaS and Cs2S QDs as they as well as their substrates [Ca(NO3)2] hydrolyzed. Calcium compounds formed complexes with Ap and alkaline solution from CsOH could produce cesium salts of Ap as well as cause oxidation of Ap.

된장으로부터 분리된 Bacillus subtilis CBD2의 생육특성 및 amylase 활성

In this study, one GRAS strain was screened from doenjang, a traditional Korean fermented food, as a microorganism producing amylase due to the formation of a clear zone on the medium including soluble starch. From the analysis of the gene sequence of 16S ribosomal RNA, the strain was identified as Bacillus subtilis and was therefore named Bacillus subtilis CBD2. When the nutrient broth medium was prepared with 3% NaCl, 5% glucose, and the initial medium pH 7.0, the B. subtilis CBD2 showed maximum growth. Among soluble starch, corn starch, maize amylopectin, and wheat starch, soluble starch was the most effective carbon source in the production of amylase by B. subtilis CBD2. The amylase from B. subtilis CBD2 showed the highest activities at pH 8.0 and 50°C, and corn starch was the most proper substrate for the enzyme activity. When corn starch was used as a substrate, the production of sugars through enzyme activity increased for 24 h, and then the enzyme activity became constant.

Dissolution behaviors of waxy maize amylopectin in aqueous-DMSO solutions containing NaCl and CaCl2

Dissolution behavior and molecular conformation of waxy maize amylopectin in aqueous DMSO solutions containing different amounts of water and salts (NaCl or CaCl2 up to 0.2 M) were characterized using multi-angle laser light scattering (MALLS; micro-batch mode) and dynamic light scattering (DLS) detectors. The solubility of amylopectin decreased and the molecular size measured increased when the water content in the DMSO increased, indicating that amylopectin chains tended to be less dissociated or aggregate by the excess amount of water. The amylopectin in aqueous DMSO solutions (10–50% water) had a spherical shape with a regular star structure, but the individual amylopectin chains were not affected by water content. Minor addition of salts facilitated the dissolution of amylopectin in aqueous DMSO solutions, possibly due to water cluster formation by the salt ions. However, a minute presence of salts (0.01 and 0.05 M) could induce the chain association even in 90% DMSO solution.

Integration of Quality Protein in Waxy Maize by Means of Simple Sequence Repeat Markers

ABSTRACTWaxy, that is, pure, amylopectin maize (Zea mays L.) is an important staple food and vegetable in Southeast and East Asia. Its insufficient protein quality could be remedied by the opaque‐2 gene mutation, demanding the combination of two recessive endosperm quality genes, opaque‐2 (o2o2) and waxy (wxwx). Crosses were made between waxy and opaque‐2 maize as female and male parents, respectively. In the segregating progenies of two crosses, Kwi1 × AgQ53 and Kwi9 × AgQ53, immediate selfing or one‐time backcrossing to the waxy parent before selfing were used to achieve the combination o2o2wxwx, supported by marker‐assisted selection (MAS) of opaque‐2 by phi057 and of waxy by phi022. The final 11 o2o2wxwx lines were achieved both from initial backcrossing and selfing. All the o2o2wxwx lines were of acceptable agronomic vigor and had very high percentages of amylopectin. The sugar content was mostly higher in both selfing and backcrossing lines than in the parental waxy lines, an advantage for vegetable marketing. High lysine and tryptophan contents of the o2o2wxwx lines prove that the goal of combining two quality traits within one grain was achieved. Furthermore, high variation in grain quality traits is an incentive for further improvement by breeding. Consumption of high‐quality protein maize will improve the diets of children, a good reason to produce double‐quality vegetable waxy maize.

Solubilization Effects on Molecular Weights of Amylose and Amylopectins of Normal Maize and Barley Starches

ABSTRACTStructural characteristics of starches have been important to determine their physicochemical and functional properties. Solubilization procedures were tested to find a higher solubilization percentage and thereafter to study the structural characteristics of amylose and amylopectin. Size‐exclusion chromatography with refractive index (SEC‐RI) system using a pullulan standard curve was tested to study the amylose molar mass. Also, a microbatch system using a MALLS detector was used to determine the molar mass and gyration radius of starch and amylopectin. Microwave heating produced higher solubility percentages than autoclaving, and there was a difference between both starches. The sample solubilized with microwave heating presented higher molar mass and gyration radius values than autoclave samples, showing that this process for structural studies provided information representative of the initial starch sample. When starch components were separated, amylose showed lower purity than amylopectin. Lower purity was obtained for amylose separated from barley starch, but no difference was obtained for purity of amylopectin separated from both starches. Barley amylopectin had a higher solubility percentage than maize amylopectin. Molar mass of barley amylose was 1.03 × 105 g/mol and for maize of 2.25 × 105 g/mol. Molar mass values of amylopectin separated from both starches were lower than the starch counterparts, although the same solubilization procedure (microwave heating) was used. The difference might be due to depolymerization during separation of starch components.

Physicochemical Characteristics of Starches from Unripe Fruits of Mango and Banana

AbstractMango and banana starches were isolated from unripe fruits and their morphology; thermal and pasting properties; molar mass and chain length distribution were determined. Mango starch granules were spherical or dome‐shaped and split, while banana starch had elongated granules with a lenticular shape. Amylopectin of both fruit starches had a lower molar mass than maize starch amylopectin; however, mango amylopectin had the highest gyration radius. Banana amylopectin showed the lowest percentage of short chains [degree of polymerization (DP) 6–12] and the highest level of long chains (DP ≥ 37); mango amylopectin presented the highest fraction of short chains, but the level of longest chains was intermediate between those of banana and maize amylopectins. Banana starch presented the highest average gelatinization temperature followed by mango starch and maize starch had the lowest value; a similar pattern was found for the gelatinization enthalpy. The two fruit starches had a lower pasting temperature than maize starch, but the former samples showed higher peak and final viscosities than maize starch. Structural differences identified in the fruit starches explain their physicochemical characteristics such as thermal and pasting behavior.

Structure and Some Physico-chemical Characteristics of Tuber Starch of Three Cultivars of Chinese Arrowhead and Their Six F1 Lines.

Starch granules were prepared from tubers of Chinese arrowhead (Sagittaria trifolia L. var. edu-lis (Sieb.) Ohwi), 3 cultivars: Aokuwai (Ao), Shirokuwai (Shi) and Suitakuwai (Sui), and their 6 F, lines: Ao×Ao, Ao×Shi, Ao×Sui, Shi×Ao, Shi×Sui and Sui×Sui. The amylose content of the starches determined by amperometric iodotitrimetry were in a range of 28.2-29.9% and 26.6-31.3% by gel-permeation chromatography (GPC) of isoamylase-debranched starches. High performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) of isoamylase-debranched starches showed the starches had unique amylopectin short chain length distributions of increased amounts of chains with DP 6 and 7, and decreased amounts of chains with DP 9 compared with waxy maize amylopectin. The X-ray diffractograms of the starches showed A type patterns. Among the 3 cultivars, the granular size and temperature of gelatinization by DSC of the starches were in the ascending order of Shi > Ao > Sui, and starch-granule digestibility by amyl-ase and solubility and swelling power at 70°C of the starches were in the descending order of Shi >Ao>Sui. There were positive correlations between starch-granule digestibility by amylase and either solubility at 60°C and 70°C or swelling power at 60°C and 70°C of the starches, and negative correlations between starch-granule digestibilities by amylase and temperatures of gelatinization (To and Tp) by DSC of the starches.

Study on Outer Chains Released from Amylopectin between Immobilized and Free Debranching Enzymes.

Various kinds of partial hydrolysates of waxy maize amylopectin were prepared by controlling the debranching actions of immobilized and free isoamylase, and free pullulanase, and then frac tionated into three fractions by a gel chromatography using Toyopearl HW-65F . The smallest frac tions (fr. 3) were again debranched with free isoamylase and analyzed by HPAEC-PAD in order to obtain information of chain distributions existing in the outer portion of amylopectin molecules. About 10-15% of the partial hydrolyses were appropriate to collect the shortish chains released from amylopectin. The chain distribution of the smallest fraction consisted of many short-chains with DP 6-15, and it could be thought that most of the shortish chains might be A chains derived from outer portions of amylopectin. The comparative experiments among the debranching enzymes led us to confirm that partial hydrolyzed materials obtained by the low enzyme activity of free isoamylase and pullulanase could be used to study the outer chains of amylopectins like immobilized isoamylase.

The effect of amylose content from differing botanical sources on the nonlinear viscoelastic properties of semidilute solutions of maize starches* This article is a US Government work and, as such, is in the public domain in the United States of America. *Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of

The effect of the addition of potato or maize on the shear-thickening behavior of semidilute solutions of maize was examined. The experiments were conducted at 25°C using 90/10 weight–weight dimethyl sulfoxide (DMSO)–water as the solvent. The addition of amylose to maize amylopectin reduced and eventually eliminated the observed shear-thickening behavior of maize amylopectin. When potato amylose was combined with maize amylopectin, the shear-thickening phenomenon was observed up to a total amylose content of 10% by weight. For maize amylose, the shear-thickening behavior was eliminated at an amylose content of 5%. Maize amylose is thus more effective in inhibiting the formation of the structure formed after the shear-thickening region than potato amylose. This result indicates that the amylose obtained from potatoes interacts differently, or entangles differently, with maize amylopectin than does the amylose obtained from maize. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2429–2436, 1999