Commercial Maize Starch Research Articles

Exploring starches from varied sorghum genotypes compared to commercial maize starch

AbstractSorghum has been lately attracted the attention for human consumption as a gluten‐free cereal rich in bioactive compounds. Sorghum starches isolated from brown (BRS305), red (BRS308), and white (CMSXS180) genotypes were compared to commercial maize starch, based on proximate composition, particle size distribution, microstructure, X‐ray diffraction, amylose and total starch content, solubility index, swelling power, pasting, and thermal properties. The carbohydrate content of sorghum starch samples ranged from 98.24 to 99.23 g/100 g (dry basis). The particle size distribution of the CMSXS180 sorghum genotype was very similar to commercial maize starch. The relative crystallinity values varied from 29.83% to 30.39%. The water solubility index and swelling power of sorghum starches were lower than those of maize starch. Sorghum genotypes paste profiles were similar, but greatly differed from maize showing the highest final viscosity (4042.0–4444.5 cP) compared to maize starch (3767.5 cP) and lower gelatinization enthalpy (∆H = 9–10.5 J/g) than maize starch (11.8 J/g). The results showed some distinct properties of sorghum starches when compared to maize starch, which may contribute to provide alternative uses, particularly in food products requiring very high viscosity and retrogradation.Practical ApplicationsSorghum pericarp is rich in bioactive compounds, which can be used as a main source of ingredients, for example, to the nutraceutical industry. The sorghum grain without pericarp (decorticated), used to produce purified starch (without chemical treatment), may contribute to the total use of this cereal by limiting chemical residues. In addition, sorghum starch has shown particular technological properties different from commercial maize starch, providing alternative uses in the food industry, for example, in products that require high viscosity from hot to cold processes.

Biodegradable Carbon-based Ashes/Maize Starch Composite Films for Agricultural Applications.

The aim of this work is the development and characterization of biodegradable thermoplastic recycled carbon ashes/maize starch (TPAS) composite films for agricultural applications. A proper plasticizer, that is, glycerol, was added to a commercial maize starch in an amount of 35 wt.%. Carbon-based ashes were produced by the biomass pyro-gasification plant CMD ECO 20, starting from lignocellulosic wastes. The ashes were added to glycerol and maize native starch at different amounts ranging from 7 wt.% to 21 wt.%. The composite was mixed at 130 °C for 10 min and then molded. The effect of the different amounts of carbon based ashes on the thermal and physical-mechanical properties of the composite was assessed by using several techniques, such as rheology, wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), moisture absorption, degradation and mechanical tests. The presence of the carbon waste ashes allows to improve thermal and durability performances of the thermoplastic starch (TPS) films. It reduces the water absorption of starch matrix and strongly decreases the deterioration of starch, independently from fillers amount, enhancing the lifetime of the TPS films in outdoor conditions. In addition, the waste carbon ashes/maize starch films present an advantage in comparison to those of neat starch; it can biodegrade, releasing the plant nutrients contained in the ashes into the soil. In conclusion, this approach for recycling carbon waste ashes increases the efficiency of industrial waste management, along with a reduction of its impact on the environment.

Biodegradable extruded thermoplastic maize starch for outdoor applications

In the recent years, great progress was achieved in the development of biodegradable products based on agricultural raw materials. Among them, one of the most promising and diffused biomaterials is represented by starch. For this reason, different approaches have already been explored to use starch as a natural source for the production of biodegradable thermoplastic polymers. However, there is still a lack of a controlled, easy and cheap procedure to process maize native starch in order to obtain a highly performing thermoplastic polymer. The purpose of this paper is the development of a simple and reproducible method able to produce a thermoplastic starch that can be easily transformed into extruded objects, suitable for several potential applications. To reach this aim, a proper plasticizer was added to a commercial maize starch at different concentrations corresponding to mass fraction from 50 to 70% (in the following text %). The effect of the different amounts of the plasticizer on the processability of the starch powder was assessed by varying the parameters during the extrusion process. The interaction of the structure of starch with the plasticizer, firstly, and the final thermal and physical–mechanical properties of the extruded thermoplastic starch samples, secondly, were analysed by using several techniques: differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, UV transmittance, moisture absorption, colorimetric and mechanical tests. The samples containing 50% of plasticizer, in possess of the best physical and thermal performances, were further characterized in terms of durability, in order to predict their lifetime in outdoor conditions, by using artificial ageing tests, such as moisture absorption and QUV accelerated weathering tests.

Physicochemical and Morphological Properties of a Small Granule Legume Starch With Atypical Properties From Wild Mango (Cordyla africana L.) Seeds: A Comparison to Maize, Pea, and Kidney Bean Starch

The physicochemical properties of wild mango (Cordyla africana L) seed starch are assessed and compared to bean, pea, and commercial maize starch. Scanning electron microscopy (SEM) and polarized optical microscopy (POM) show that wild mango starch granules are truncated (cap‐shaped) have smooth surfaces, and are much smaller (5.7 μm) than bean (28.2 μm), pea (23.0 μm), and maize (11.1 μm) starch granules. Wild mango starch had a higher (p ≤ 0.05) gelatinization temperature (differential scanning calorimetry‐DSC, Tp = 77 °C), but a lower enthalpy (ΔH = 10.7 J g−1) than pea, bean, and maize starches. X‐ray diffraction (XRD) reveals a C‐type crystalline pattern, while Fourier transform infrared spectroscopy (FTIR) indicates that the starch has a higher degree of short‐range order compared to bean, pea, and maize starches. Rapid visco analysis (RVA) shows that its peak paste viscosity (2811 cP) is significantly (p ≤ 0.05) higher than that of bean, pea, and maize starch. Wild mango starch is similar (p > 0.05) to maize starch in terms of RVA granule‐breakdown and gelation‐related parameters, and gel texture (firmness = 114.7 N and strength = 339.4 ± 16.5 J), differed significantly (p ≤ 0.05) from bean and pea starch.

Isolation and partial characterization of starch from banana cultivars grown in Colombia

Banana starch is resistant to hydrolysis by digestive enzymes due to its structure and dietary fibre content. Starch was isolated from the following three cultivars of Colombian Musaceae: Gros Michel (dessert), Dominico Harton and FHIA 20 (cooking); also, the amylose and amylopectin contents, morphology of the granules, thermal properties, pasting, molecular characteristics and digestibility were determined. The total starch content, amylose content and digestibility (gelatinized starch) were higher in cooking varieties; the purity and gelatinization temperature were similar for the three varieties, but the enthalpy was higher in the dessert variety. The three varieties showed higher viscosities in the pasting profile compared to commercial maize starch in both acid and neutral conditions. Starch granules presented with heterogeneous sizes and shapes (elongated and ovals) that had birefringence. The Dominico Hartón variety showed the lowest rapidly digestible starch (RDS) value in the gelatinized sample that is in agreement with the greater proportion of long chains.

Pilot scale production and in vitro gastro-small intestinal digestion of self-assembled recrystallised starch (SARS) structures

Two commercial maize starches (Hylon VII, HA7; and normal maize starch, MS) and a potato starch were processed in the presence of palmitic acid (C16:0, Palm) at 140 °C followed by retrogradation in order to produce self-assembled recrystallised starches (SARS). The new starch structures prepared from HA7 exhibited a stronger birefringence pattern under polarised light and greater relative crystallinity (%) than those prepared from potato and normal MS. Also, the SARS from HA7 showed a typical Vh pattern (2Ө: 8.5°, 15°, 23°) confirming a strong inclusion complexation between amylose and fatty acid. Effect of other fatty acids (stearic, C18:0 and oleic, C18:1) on SARS formation was also studied using HA7. The degree of relative crystallinity (%) of these samples showed an order of palmitic > oleic > stearic, with the former also showing greater yield (YSARS). The transition temperatures and enthalpies of melting or dissolution for SARS prepared from HA7 and three fatty acids (further referred to as HA7-SARS) ranged between 101 and 131 °C and 11–18jg−1, respectively. The scanning electron micrographs of the freeze-dried HA7-SARS showed the presence of aggregated round and disc/torus shaped morphologies in varying amounts. An in vitro starch digestion model was used to study the kinetics of glucose release during digestion of ground and cooked HA7-SARS for 120 min. All the HA7-SARS samples exhibited slower and significantly lower overall starch hydrolysis than the native HA7 starch (70%), with the SARS prepared using palmitic acid showing the lowest hydrolysis (44%). Digesta from the latter also showed the presence of intact microparticles resistant to gastro-small intestinal digestion.

Effect on in vitro starch digestibility of Mexican blue maize anthocyanins

The purpose of this study was to evaluate the effect of blue maize extracts obtained by acid-methanol treatment on the nutritional in vitro starch fractions such as: rapidly digestive starch (RDS), slowly digestive starch (SDS) and resistant starch (RS) of native and gelatinized commercial maize starch. Chromatographic analysis (HPLC-DAD/ESI-MS) of blue maize extracts showed the presence of seven anthocyanins, where cyanidin-3-(6″-malonylglucoside) was the main. Blue maize extracts modified nutritional in vitro starch fractions (decrease of RDS) while RS content increased (1.17 and 2.02 times for native and gelatinized commercial maize starch, respectively) when anthocyanins extracts were added to starch up to 75% (starch weight). This preliminary observation provides the basis for further suitability evaluation of blue maize extract as natural starch-modifier by the possible anthocyanins-starch interaction. Anthocyanin extracts can be a suitable to produce functional foods with higher RS content with potential human health benefits.

Characterization of the physicochemical and thermal properties of unexplored starches with potential industrial uses from six Brazilian maize landraces

Starches isolated from six maize landraces from Brazil were investigated for their physicochemical, morphological, structural and thermal properties and compared to a commercial maize starch (COM). Similarities (chemical composition) and differences (structural characteristics) were observed. The crystallinity of starches ranged between 18.5 and 25.0%. The swelling power at 65°C ranged between 3.00 g/g Pires (PIR) and 4.82 g/g Mato Grosso (MT), whereas at 90°C varied between 18.8 g/g (PIR) and 23.9 g/g (MT), differing from COM, i.e., 14.6 g/g. The starch granule's morphology and size determined by SEM showed polyhedral and spherical shapes and a heterogeneous size distribution between 1.7 and 25 µm. The gelatinization process studied by DSC showed that transition temperatures (T0, Tp, Tc) ranged between 61.0–65.9, 67.5–71.7, and 75.2–76.8°C, respectively, and enthalpies (ΔHgel) between 11.4 and 13.3 (J/g). The retrogradation properties were analyzed after storage for 7, 14, and 40 days at 4°C; the retrogradation degree changed with the time and among the different starches, as well as the transition temperatures and enthalpies, which were lower than those observed for the gelatinization process. Other parameters like gelatinization and retrogradation temperature range (Rgel, Rret) and PHI were analyzed. Rgel was faster for BR and slower for MT, while Rret was broader than the corresponding gelatinization and PHI was not significantly different among the studied starches, except for the BR (slightly higher value).

Starch viscoelastic properties studied with an acoustic wave sensor

Gelatinization and retrogradation of starch was followed in real time with an acoustic wave sensor. This study relies on the monitorization of the frequency of oscillation of a piezoelectric quartz crystal in contact with a 2.5% emulsion of a commercial maize starch, during heating and cooling. The technique showed to be very powerful and sensitive to most of the changes described in the literature, which have been elucidated by some other techniques. The value for the temperature of gelatinization found using the sensor was confirmed by the analysis of the same starch emulsion by polarized light microscopy. Temperatures of gelatinization were found to vary with the sample heating rate, as follows: 73.5°C at 2.0°C/min, 66.0°C at 1.0°C/min, and 65.0°C at 0.5°C/min. Hysteresis of the studied system was evidenced by the frequency shift before heating and after cooling till the initial temperature. Analysis performed on a 1.5% emulsion of a rice starch heated at 2.0°C/min and cooled as before, evidenced no hysteresis and showed complete reversibility, in which concerns to the series frequency of the piezoelectric quartz crystal.

Viscoelastic properties of highly concentrated maize starch solutions in DMSO

AbstractRheological measurements of highly concentrated dimethylsulfoxide (DMSO) starch solutions were performed. For all experiments commercial maize starch with different AM content was used. The research covered a wide range of polymer concentrations depending on linear fraction contribution and allowed to obtain a starch content up to 40% w/w. The analysis covered the time – concentration superposition method and fitting the continuous Maxwell model to the experimental data using Tikhonov regularization method. The results allowed statements about the viscoelastic behavior of non‐aqueous starch solutions, depending on their molecular structure. If the linear AM is the predominant component of the starch, the system behaves more elastic compared to those composed of branched AP. The effect of variation in molecular constitution is stronger than the effect of concentration of the dispersion. Additionally, the molecular masses of both fractions seems not to be the crucial factor for rheological properties as well as biopolymer solubility in DMSO. Relaxation spectra obtained from Maxwell model show the drift of the main peak to shorter relaxation times when the concentration of biopolymer is rising. The phenomenon testifies about the influence of starch concentration on elastic response of the system.

Formation of starch spherulites: Role of amylose content and thermal events

Commercial maize starches and potato starches of two cultivars differing in physicochemical composition (granule size distribution; amylose to amylopectin ratio) and crystallinity were heated to 180 °C and then cooled by fast quench using a differential scanning calorimeter (DSC), in order to produce spherulitic starch morphologies. Among the raw maize starches, waxy maize starch had highest relative crystallinity (49%) whereas a lowest crystallinity of 33–39% was calculated for high-amylose maize starches. Potato starches showed a relative crystallinity of 50%. The temperatures and enthalpies of gelatinisation and melting varied among all the starches. High-amylose maize starches showed higher transition temperatures of gelatinisation ( T gel), whereas waxy maize starch had lowest T gel and enthalpy of gelatinisation (Δ H gel). Similarly, a considerable variation in parameters related with crystalline melting ( T m1, T m2 and Δ H m1, Δ H m2) was observed for different starches. The superheated gels of different starches treated using DSC were subjected to polarised microscopy, to confirm the formation of spherulites. Both the high-amylose starch gels showed the presence of spherulites exhibiting birefringence and a weak crystalline pattern. No birefringence was observed for waxy maize starch gel, while potato starch gels had some birefringence. The particle size distribution of high-amylose maize starch gels analysed through Zetasizer showed the sizes of spherulitic particles fall in the range of 300 nm–900 nm. The scanning electron micrographs of the dried high-amylose maize starch gels showed the presence of round spherulites consisting of several aggregated spherulitic particles. Amylose content and melting of crystallites during heating play an important role during recrystallisation of amylose (spherulite morphologies).

Physicochemical properties of acha (Digitaria exilis and Digitaria iburua spp) grains

Some physicochemical properties of two varieties of acha (Digitaria exilis and Digitaria iburua) were studied. Physical properties including kernel size, 1000-kernel weight, and water absorption rate of the grains were determined. Water absorption reached a maximum after steeping for 25 hours. The starch content exhibited a two-stage pattern of swelling and solubility properties similar to other non-waxy cereal starches. Starch from Digitaria exilis swelled less than Digitaria iburua. Chemical compositions such as crude protein, lipid, crude fibre, ash, nitrogen-free extract (NFE) and amylose were also determined. Amylose contents of 268 g.kg−1 and 276 g.kg−1 were obtained for the white and brown varieties respectively. Data were analysed using analysis of variance. Duncan's test was used to separate the sample means that were significantly different. It was concluded that acha starch has properties similar to commercial maize starch and could be used for similar industrial purposes.

Effect of Ferulic Acid and Catechin on Sorghum and Maize Starch Pasting Properties

ABSTRACTThe effects of ferulic acid and catechin on starch pasting properties were studied as part of an investigation into the structure and functionality of phenolics in starch‐based products. Commercial maize starch, starches from sorghum cultivars (SV2, Chirimaugute, and DC‐75), and the phenolic compounds ferulic acid and catechin were used in the investigation. Pasting properties were measured using rapid viscosity analysis. Ferulic acid and catechin (up to 100 mg each) were added to maize or sorghum starch (3 g, 14% mb) in suspensions containing 10.32% dry solid content. Addition of catechin resulted in pink‐colored pastes, whereas ferulic acid had no effect on paste color. Ferulic acid and catechin decreased hot paste viscosity (HPV), final viscosity, and setback viscosity of maize and sorghum starch pastes, but had no influence on the peak viscosity (PV) of the former. Both phenolics increased breakdown viscosity. Ferulic acid had greater influence on HPV, final viscosity, breakdown, and setback than catechin. Addition of catechin under acidic conditions (pH 3) decreased HPV, final viscosity, and setback of maize starch, but alkaline conditions (pH 11) slightly increased setback. Both acidic and alkaline conditions resulted in increased breakdown. Investigations on model‐system interactions between ferulic acid or catechin and starch demonstrated that phenolic type and pH level both significantly influence starch pasting properties, with ferulic acid producing a more pronounced effect than catechin. The significance of these interactions is important, especially in food matrices where phenolics are to be added as functional food ingredients.

Paste and Gel Properties and In Vitro Digestibility of Tef [Eragrostis tef (Zucc.) Trotter] Starch

AbstractProperties of tef starch from five varieties were compared with commercial maize starch. In most tef varieties the paste clarity (measured as % T) was similar to that of maize starch, but the paste was visually less white in colour. Tef starch gel texture was short and in most varieties was slightly firmer than that of maize starch. Tef starch adhesiveness was less than maize starch. Retrogradation extent of tef starch evaluated, as % gel syneresis under storage at 4 °C and ‐18 °C at 3, 7, 10 and 21 storage test days, was lower than that of maize starch. Storage with three freeze‐thaw cycles (‐18 °C 24 h; 23 °C 6 h) gave a similar trend. In tef starch initial digestion by α‐amylase and hydrolysis by mild HCl treatment was slightly higher than in maize starch, probably in part because of the smaller granule size and higher amorphous portion of tef starch. Alpha‐amylase degradation of tef starch granules was by surface erosion, probably due to the absence of surface pores in the granules.

Physico-chemical Characterization of Grain Tef [Eragrostis tef (Zucc.) Trotter] Starch

Starch isolated from five grain tef (Eragrostis tef) varieties was characterized and compared with commercial maize starch. Grain tef starch is formed of compound granules, comprising many polygonal shape (2—6 μm in diameter) simple granules. The crude composition is similar to that of normal native cereal starches. The amylose content ranges from 24.9—31.7%. Gelatinisation temperature range was 68.0—74.0—80.0 °C, typical of tropical cereal starches, and resembling the temperature range of rice starch. The mean intrinsic peak viscosity (269 RVU), breakdown viscosity (79 RVU), cold paste viscosity (292 RVU) and setback viscosity (101 RVU) determined were considerably lower than that of maize starch. Tef starch has higher water absorption index (WAI) (mean 108%) and lower water solubility index (WSI) (mean 0.34%) than maize starch.

Laboratory Procedure to Wet‐Mill 100 g of Grain Sorghum into Six Fractions

ABSTRACTA small‐scale (100 g of grain) procedure was developed to wet‐mill grain sorghum into six fractions by modifying the procedure of Eckhoff et al (1996). The wet‐milling process was repeated five times on commercial grain sorghum, and the mean yield (69.4%) of starch (≤0.3% protein) varied by 0.3%, whereas the yields of fiber, gluten, and germ plus bran fractions varied by 5–6%. The starch fraction accounted for ≈95% of that in the grain, while the total solids recovered was 99.0%. Four other samples of grain sorghum gave 92–95% recoveries of starches and 98.2–99.8% recoveries of total solids. All grain sorghum starches had lightness (L*) values and pasting curves nearly equal to those of a commercial maize starch.

Maize Starch Biphasic Pasting Curves

The pasting of commercial maize starches was found to be a biphasic phenomenon, exhibiting an expected first viscosity peak as well as an unexpected, relatively large second viscosity peak under specific cooking conditions when using a Rapid Visco Analyser (RVA). The second peak formed at long holding times (between 32 and 45 min), holding temperatures within the range of 82 to 95 °C, starch concentrations from 8 to 13% with a wide range of initial heating rates (0·5–10 °C/min) and shear conditions (150–500 rev/min). The second pasting peak is attributed to the formation of complexes between amylose and low levels of lipid present in maize starch. When lipid was partially removed by extraction with methanol-chloroform (1 : 3 v/v), the second pasting peak disappeared. When, however, the starch sample was treated with solvent and the solvent removed by evaporation, the second peak remained, but formed earlier. Increasing the holding temperature gave a slightly higher first viscosity peak, slightly earlier, and led to a decrease in the area and height of the second viscosity peak. Increasing heating rate also led to an earlier, slightly higher first peak and earlier but lower second viscosity peak. Increasing starch concentration led to an increase in height and area of both the first and second peaks and their later occurrence. Increasing shear led to a decrease in height and area of both the first and second peaks and their later appearance.

Starch properties as affected by sorghum grain chemistry

To determine the relationship between sorghum grain polyphenol content, grain structure, and starch properties, starch was isolated from 10 sorghum varieties using an alkali steep and wet-milling procedure. SV2, a tannin-free variety with white pericarp, gave a white starch. Varieties having red or white pericarp and higher polyphenol levels gave pink starches. Hunter colour values (L, a, b) of starches were not correlated with grain polyphenol content. Grain appearance in terms of pericarp colour, or presence or absence of pigmented testa, did not relate to the intense pink colouration of sorghum starches. Starch amylose content was significantly negatively correlated (r = −0.88, p < 0.001) to grain floury endosperm texture. Sorghum starches had higher peak viscosity (PV) in pasting than commercial maize starch. The time taken to reach peak viscosity from the initial viscosity rise was less for sorghum starches than maize starch. However, sorghum starches had a higher rate of shear thinning (Rst) than maize starch. There was a significant positive correlation between grain polyphenol content and starch PV (r = 0.75, p < 0.05). Starch gel hardness was negatively correlated to pasting properties of Rst and paste breakdown (r = −0.78 and −0.77 respectively) at p < 0.01. Peak gelatinisation temperature (Tp) occurred over a narrow range from 66 to 69 °C. Tp was negatively correlated to the floury endosperm portion of the grain (r = −0.77) at p < 0.01. It is concluded that sorghum grain polyphenol content and grain characteristics influence its starch properties. © 2000 Society of Chemical Industry

Experimental and modelling studies of the flow properties of maize and waxy maize starch pastes

Methods have been developed for characterising the time-dependent and non-Newtonian rheological behaviour of gelatinized maize starch pastes as a function of starch concentration, temperature and shearing conditions. Two types of commercial maize starch were used in this study: a normal maize with 30% amylose, and a waxy maize consisting mainly of amylopectin. Results from transient flow property measurements using a concentric cylinder viscometer show that the starch pastes are strongly thixotropic and shear thinning as characterised by a viscosity that decreases with time and rate of shear. The rheology of the starch pastes studied can be satisfactorily modelled using the structural kinetic approach which postulates that after gelatinization and cooling, the polysaccharide polymers and the swollen starch granules form network structures which are irreversibly broken under shear leading to the time- and shear-dependent change in the flow properties. At equilibrium, the starch pastes exhibit pseudoplastic behaviour which can be described by the power law model. While pastes of the two maize starches studied exhibit similar rheological behaviour at the same starch concentration and temperature, the normal maize starch paste is more viscous initially in the gel state, but breaks down more rapidly and becomes thinner than the waxy maize starch paste under the steady-state sheared condition. This difference is due to the different gel structures formed on cooling, and to the different swelling characteristics of the granules of the two maize starches studied.

Physico‐chemical and Functional Properties of Common Bean (Phaseolus vulgaris) Starches

AbstractStarch was isolated by a simple procedure from two varieties of Phaseolus vulgaris with outstanding agronomic performance. These varieties were negro queretaro and bayocel which have black and light brown colored seeds, respectively. The starch yields were 31.5% for negro qro. and 28.5% for bayocel. Commercial maize starch was used as reference. The granule size followed the order: negro qro. &gt; bayocel &gt; maize. Compared to maize starch, the legume starches had at least a similar water absorption capacity, formed a stable gel at lower concentrations and showed a Hunter total color closer to the employed white standard. The swelling and solubility were both temperature and pH dependent. Effects of pH on the pasting properties were also examined with the Brabender Viscograph. The viscosity of legume starches was increased after holding the paste at 90°C for 15 min. The retrogradation tendency of maize starch was much higher than that of legume samples. The physico‐chemical and functional properties of common bean starches might suit some food industrial applications.