Cassava Starch Granules Research Articles

Investigation of the photo-oxidation of cassava starch granules

In this study, the combined and simultaneous actions of H2O2 and UV radiation on cassava starch granules were applied and the thermal, rheological, structural and colour properties were investigated. Samples of native cassava starch were oxidised with standard H2O2 solutions (0.1, 0.2 and 0.5 mol L−1) and exposed for 1 h under UV light (UVC radiation with λ = 256 nm), with constant stirring. The solutions were subsequently filtered, washed, dried and analysed. The thermogravimetric curves showed similar behaviour, with three main mass losses and an increase in the thermal stability of each sample. The oxidative modification performed caused a strong decrease in the setback and final viscosity parameters (RVA), a gradual decrease in the gelatinisation enthalpy (DSC) and relative crystallinity (XRD) and significant differences in the average roughness of the granules (NC-AFM). The X-ray diffraction powder patterns displayed the “A” type for all the starch granules. The colour parameters showed a decrease in the −a* value (trend to green) for all the treated samples.

Preparation and characterization of cassava starch‐based adsorbents for separating of azeotropic ethanol‐water in biofuels ethanol production

AbstractBackgroundDehydration of biomass‐based fermentation product is an essential process in the production of biofuels ethanol for industrial applications. Cassava starch, an adsorbent with high efficiency, can be fermented after saturating with water, which overcomes the shortcomings of high energy consumption bioethanol production. Therefore, the aim of the present study was to prepare cassava starch‐based adsorbents with high adsorption efficiency that do not affect fermentative production.ResultsPorous cassava starch granules, which can be fermented to produce biofuel ethanol, were formed through the partial hydrolysis of starch using amylase and ultrasonication. The structural changes in cassava starch granules were also studied to prove that porous starch could be reused as feedstock for biomass‐based fuel ethanol production after adsorption. Finally, an adsorption experiment proved that the modified cassava adsorbents had better absorptive properties than the native cassava.ConclusionThese structural changes in cassava starch granules showed that porous starch is an efficient adsorbent that can be reused after adsorption as feedstock for fuel ethanol, which increases the energy efficiency of ethanol–water azeotrope separation. © 2015 Society of Chemical Industry

Physicochemical properties of starches and proteins in alkali-treated mungbean and cassava starch granules

This study explored the influences of envelope integrity of cooked starch granules on physicochemical and thermophysical properties of mungbean and cassava starches. Alkali treatment was used to selectively leach amylose from the amorphous region of both starches and partially fragmented starch molecules into lower-molecular-weight polymers. It was found that despite the loss of 40% of the original content of amylose, both mungbean and cassava starches retained similar crystallinities, gelatinization temperature ranges, and pasting profiles compared to the native starches. However, the loss of granule-bound starch synthases during alkali treatment and subsequent alkali cooking in excess water played significant roles in determining granular disintegration. The alterations in envelope integrity due to the negative charge repulsion among polymers within the envelope of swollen granules, and the fragmentation of starch molecules, were responsible for the alterations in thermophysical properties of mungbean and cassava starches cooked under alkaline conditions.

Limited Hydrolysis of Insoluble Cassava Starch Granules Results in Enhanced Gelling Properties

Limited Hydrolysis of Insoluble Cassava Starch Granules Results in Enhanced Gelling Properties

The thermal, rheological and structural properties of cassava starch granules modified with hydrochloric acid at different temperatures

Starch is arguably one of the most actively investigated biopolymer in the world. In this study, the native (untreated) cassava starch granules (Manihot esculenta, Crantz) were hydrolyzed by standard hydrochloric acid solution at different temperatures (30°C and 50°C) and the hydrolytic transformations were investigated by the following techniques: simultaneous thermogravimetry–differential thermal analysis (TG–DTA), differential scanning calorimetry (DSC), as well as non-contact atomic force microscopy (NC-AFM), X-ray diffraction (XRD) powder patterns, and rapid viscoamylographic analysis (RVA). After the treatment with hydrochloric acid at different temperatures, the thermal stability, a gradual loss of pasting properties (viscosity), alterations in the gelatinization enthalpy (ΔHgel), were observed. The use of NC-AFM and XRD allowed the observation of the surface morphology and topography of the starch granules and changes in crystallinity of the granules, respectively.

Thermal, rheological, and structural behaviors of natural and modified cassava starch granules, with sodium hypochlorite solutions

The use of chemically modified starches is widely accepted in various industries, with several applications. In this research, natural cassava starch granules were treated with standard sodium hypochlorite solution at 0.8, 2.0, and 5.0 g Cl/100 g starch. The native and modified starch samples were investigated by means of the following techniques: simultaneous thermogravimetry–differential thermal analysis, which allowed us to verify the thermal decomposition associated with endothermic or exothermic phenomena; and differential scanning calorimetry that was used to determine gelatinization enthalpy as well as the rapid viscoamylographic analysis that provided the pasting temperature and viscosity. By means of non-contact-atomic force microscopy method and X-ray powder patterns diffractometry, it was possible to observe the surface morphology, topography of starch granules, and alterations in the granules’ crystallinity.

Effects of Pneumatic Conveying Drying Conditions on Damaged Starch Content and Particle Size of Cassava Starch

This research aimed to investigate the effects of pneumatic conveying drying conditions on damaged starch content and particle size of cassava starch using response surface methodology. Three parameters of interest, i.e. drying air temperature (120, 160, and 200oC), drying air velocity (20, 30, and 40 m/s), and feed moisture content (40, 50, and 60% d.b.), were varied. Experimental results showed that damaged starch content and average particle size of cassava starch before drying were approximately 0.45% and 21.47µm, respectively. However, after drying, the values were altered to approximately 0.69 to 6.84% and 15.40 to 31.67 µm, respectively. The drying air temperature, drying air velocity, and feed moisture content significantly affected the changes. The results indicated that cassava starch granules were damaged and then agglomerated into large particle during pneumatic conveying drying depending on operation conditions.

Gelatinization properties of native starches and their Näegeli dextrins

Cassava, potato, sweet potato, and Peruvian carrot starches were hydrolyzed with 15% v/v sulfuric acid solution for up to 30 days. Naegeli dextrins obtained from 1, 3, 6, 12, and 30 days were evaluated using differential scanning calorimeter (DSC) and scanning electron microscopy (SEM). Two phases of hydrolysis were found. The first phase was attributed to faster degradation of amorphous areas of granules, whereas the second phase corresponded to slower degradation of crystalline regions. Peruvian carrot starch was the most susceptible to acid, whereas potato and sweet potato starches were the most resistant. From DSC, it was observed a progressive reduction in peak height and a broadening of peaks with increasing hydrolysis time. The peaks shifted to higher temperatures. Onset temperature decreased on first day of hydrolysis for cassava and Peruvian carrot starches, and on third day for potato and sweet potato. Enthalpy decreased during first stage of hydrolysis in cassava and Peruvian carrot starches, and during second phase, it reduced in all starches. SEM showed that the granule surfaces were degraded by erosion on the first day of treatment, followed by degradation of amorphous areas. On third day, potato and sweet potato starches still displayed some granules almost intact, whereas cassava and Peruvian carrot starch granules were totally degraded, confirming their high susceptibility to acid attack. On sixth day of hydrolysis, starch granules had faceted structures, characteristic of crystalline material. The effect that acid hydrolysis had on thermal properties of starches depended on both hydrolysis stage and starch source.

CHEMICAL COMPOSITION, THERMAL AND VISCOELASTIC CHARACTERIZATION OF TUBER STARCHES GROWING IN THE YUCATAN PENINSULA OF MEXICO

ABSTRACT Optical microscopy, proximate analysis, differential scanning calorimetry and rheological oscillatory tests were done to evaluate the physical, thermal and rheological properties of starches isolated from the tubers makal (Xanthosoma yucatanensis), sweet potato (Ipomea batata), cassava (Manihot esculenta) and sago (Marantha arundinacea). Mean starch granule size ranged from 10.6 to 16.5 µm. Makal and sweet potato starch granules were spherical, cassava starch granules were spherical‐truncated and sago starch granules were polygonal. The proximate composition showed that overall, the starches studied were within the group of the normal ones, with low fat and protein content (<7%) and amylose content <30%. Gelatinization peak temperature range was 61.3 to 78.4C and enthalpy (ΔH) range was 9.2 to 14.9 J/g. The rheological profiles of all tuber starches exhibited viscoelastic gel‐like behavior with G′ (storage modulus) > G″ (loss modulus) at the tested amplitude and frequency ranges. Makal and sago starches are potentially useful in the manufacture of products requiring high processing temperatures. Sweet potato starch may have applications in food systems as a thickening and gelling agent, while cassava starch could be used to stabilize low viscosity foods.PRACTICAL APPLICATIONSStarch is a fundamental element of human diets and is used extensively as a functional ingredient. However, despite a global production of 48.5 million tons/annum, part of the worldwide demand remains unmet, meaning new starch isolation sources are needed (FAOSTAT 2001). With worldwide cultivation of approximately fifty million hectares (CIAT 1997), roots and tubers play a significant role in the global food system and are a vital caloric source for people in many developing countries. In Mexico, the most common cultivated roots and tubers are cassava, potato, makal, sweet potato, sago and yam bean, all most frequently eaten in the country's southeastern states (Burgos‐Perez 2005), with scarce information available about its properties. When determining the potential uses of a starch in food systems, the chemical, thermal and rheological behaviors of its pastes and gels (Wang and White 1994) are most important. Thus, results of this study may decide specific application (thickening, flow and gelling agent) of local starches in the food industry.

Structural changes of cassava starch granules hydrolyzed by a mixture of α-amylase and glucoamylase

The structural changes of cassava starch granules were studied by scanning electron microscope (SEM), X-ray diffraction (XRD), and differential scanning calorimeter after starch granules were hydrolyzed by a mixture of α-amylase and glucoamylase. The surface of starch granules was porous after hydrolysis treatment. Enzymatic erosion occurred mainly at the surface for cassava starch. The BET-specific surface area of hydrolyzed cassava starch improved 10.7 times compared with that of native starch. The powder XRD intensity of hydrolyzed starch was higher than that of native starch. The crystallinity in the hydrolyzed cassava starch increased due to hydrolysis. Compound enzymes could hydrolyze cassava starch granules at sub-gelatinization temperature, and could produce porous starch.

Effect of high‐pressure microfluidization on the structure of cassava starch granule

AbstractMicrofluidization has been applied to modify starch granules. The study was conducted to investigate the effect of microfluidization on the structure and thermal properties of cassava starch–water suspension (20% w/w). The means of optical microscopy, SEM, FTIR spectroscopy, XRD, and DSC were applied to analyze the changes in microstructure, crystallinity, and thermal property. Microscopy observations revealed that native starch granules were oval, round, and truncated in shape. After the microfluidization treatment, a bigger starch granule was partially gelatinized, and a gel‐like structure was formed on a granular surface. No significant difference in XRD patterns of the samples were observed and all samples exhibited A‐type allomorph. Crystallinity decreased with the pressure. Sample treated at 150 MPa contains 17.1% crystalline glucan polymer, lower than that of native granules which have crystallinity of about 25.8%. A lower crystallinity means poor order of crystalline glucan polymer structure in starch granules. The disruption of crystalline order within the granule was also observed by FTIR measurement. Thermal analysis using DSC indicated that the microfluidization treatment brought about a significant decrease of melting enthalpy. The gelatinization enthalpy was 12.0 and 3.0 J/g for the native sample and samples treated under the 150 MPa, respectively. The results indicate that high‐pressure microfluidization process induced the gelatinization of cassava starch, which is evaluated by a percentage of the degree of gelatinization, due to a pronounced decrease with increasing microfluidizing pressure.

Thermal characterization of partially hydrolyzed cassava (Manihot esculenta) starch granules

Cassava starch, partially hydrolyzed by fungal á-amylase, was characterized using thermal analysis, light microscopy and X-ray diffraction. Thermal degradation was initiated at lower degradation temperatures after enzymatic treatment and the DSC (Differential scanning calorimetry) analysis showed almost similar range of gelatinization temperature, but the enthalpies of gelatinization were quite increased for the partially hydrolyzed starch granules. The results suggested that the partial degradation of the starch granules was concentrated in the amorphous regions.

Some properties of starches from cocoyam (Colocasia esculenta) and cassava (Manihot esculenta Crantz.) grown in Malawi

The physicochemical and functional properties of starch from cocoyam and ten varieties of cassava grown in Malawi were studied to unravel their potential in industrial application. The properties of starch varied significantly with crop and among varieties. Cocoyam starch granules exhibited polygonal truncated shapes and small sizes (average of 7µm) while the cassava starch granules were rounded, irregular with oval and truncated ellipsoidal-granules with average size of 10.14µm. The cocoyam starch gave lower values of amylose content and paste clarity but higher phosphorus content, maximum wavelength of iodine complex absorption and blue value than cassava starches. Cassava starches gels were more stable to freeze thawing releasing 28.40 – 46.92% of the water than cocoyam which released 54.06% of its water. Swelling and solubility of both cocoyam and cassava starches increased with temperature (60-90°C). Cocoyam starch exhibited lowered swelling power and solubility than cassava starches. Gelatinization and retrogradation studies gave similar enthalpy values of gelatinization of cocoyam and cassava starch; cocoyam starch displayed higher retrogradation tendencies than cassava starches. Key words: Cocoyam, cassava, amylose, blue value, swelling, solubility, paste, freeze-thaw, gelatinization, retrogradation.

Effect of Acid‐Methanol Treatment on the Physicochemical and Structural Characteristics of Cassava and Maize Starches

AbstractPhysicochemical, structural and morphological characteristics of maize and cassava starches treated with 0.36% concentrated HCl in anhydrous methanol at 54ºC for 1–8 h were analyzed and compared. Average yield of modified starch was about 97% for both starches. The solubility of the acid‐methanol treated starches increased with temperature and after 3 h of treatment reached 93% for maize starch and 97% for cassava starch at 95ºC. After 8 h of treatment, the average size of the cassava starch granules decreased from 14.9 to 11.1 µm. The action of acid‐methanol on the maize starch was more subtle, reducing the granule average size from 11.8 to 11.3 µm. Scanning electron micrographs showed that the granule surfaces were rough and exfoliated after treatment suggesting exocorrosion that was more evident for cassava starch. From GPC, it was noted that amylose and amylopectin were partially degraded during treatment. Starch crystallinity gradually increased with duration of treatment. The amylose content decreased from 21.4 to 18.8% and from 26.3 to 23.0% and the intrinsic viscosity was reduced from 2.36 to 0.21 and from 1.85 to 0.04 for cassava and maize starches, respectively. The gelatinization temperatures increased whereas pasting viscosities decreased with reaction time, especially for cassava starch. These results suggested that the attack of acid‐methanol, which was more effective on cassava starch granules, occurred preferentially in the amorphous areas located in the granule periphery and composed of amylose and amylopectin.

Investigation on the development of sturdy bioactive hydrogel beads

AbstractBiocatalytic hydrogel beads, which retain higher activity, expand, and contract with changes in pH, having biocompatibility, are developed. Composite spherical beads of chitosan having a diameter of 1–2 mm were prepared by ionic gelation using sodium tripolyphosphate (TPP). Above 3% TPP, the activity of the enzyme decreases. The mechanical strength of the chitosan–TPP beads was further improved by the addition of clay or cassava starch granules. The immobilization of protease (fungal, Aspergillus) was done with glutaraldehyde crosslinking. The chitosan–starch hydrogel beads showed significant increase in firmness and stiffness when compared with chitosan–clay beads. The swelling studies show that the particles expand at pH 1.2 and contract at pH 7.4. The activity retention of the immobilized protease was as high as 70% and exhibited a high pH and lower temperature optima than the free enzyme. Chitosan–starch hydrogel beads exhibited degradation peaks at about 90–110°C in TGA analysis. The biocatalyst beads retained 85% of the original catalytic activity even after eight cycles of repeat use. The freeze‐dried beads has good storage stability and can be used either as artificial bioreactor systems in detergent or in therapeutic formulations © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Influences of granule-associated proteins on physicochemical properties of mungbean and cassava starches

The architecture and physicochemical properties of mungbean starch (MB) and cassava starch (CS) granules were modified by calcium cross-linking under extreme alkaline conditions (pH ∼ 12) and the addition of cysteine and calcium lactate at slightly acidic conditions (pH ∼ 5–6). The presence of calcium lactate up to 100 mM at pH ∼ 12 resulted in the low swelling of heated starch granules but high degree of starch leaching. Confocal laser scanning microscopy indicated that the formation of a rigid starch envelope induced by Ca 2+ cross-linking under extreme alkaline pH led to the massive leaching of starch content without collapsing the envelope and consequently lowered the final viscosity of both MB and CS ( P < 0.05). However, the addition of both cysteine and calcium lactate increased gelatinisation temperature of both starches. Results suggested that the protein-containing envelope plays an important role in determining the granule’s ability to retain the starch content after heat treatment and subsequent pasting and thermal characteristics of MB and CS.

Architectural changes of heated mungbean, rice and cassava starch granules: Effects of hydrocolloids and protein-containing envelope

Architectural changes of starch granules induced by heat were demonstrated using light microscopy and confocal laser scanning microscopy. Heat treatment (80 °C, 30 min) on mungbean starch, cassava starch and rice flour suspensions resulted in the rearrangement of amylose and granule-associated proteins within the deformed granules. The presence of alginate and carrageenan influenced the RVA pasting characteristics of starch/flour-hydrocolloid mixed suspensions by maintaining the granular structure of amylose-rich swollen granules or inducing the aggregation of the swollen ones. Generally, the addition of hydrocolloid increased peak viscosity, lowered breakdown and reduced setback of the flour-hydrocolloid mixed paste. This study demonstrated that the heat treatment in excess water generated the protein-containing granule envelope encasing the mungbean and cassava starch content within the deformed granules.

Physical properties of egg albumen and cassava starch composite network formed by a salt-induced gelation method

Abstract Effect of cassava starch (CS) filler on the physical properties of egg albumen (EA) and cassava starch composite (EA–CS) gels and films was investigated using EA as the continuous matrix embedded with CS granules. The composite network was formed at 55 °C; below the thermal gelation temperature of both EA and CS, using the salt-induced gelation method. Increasing the pH from 8 to 11 and NaCl from 50 to 200 mM resulted in a softer but more cohesive EA gel (p ⩽ 0.05). Raising CS content increased Young’s modulus, stress and opacity but reduced the cohesiveness of the mixed gel network (p ⩽ 0.05). The release of paprika oleoresin (O/R) from the dried EA–CS composite film into the oil phase was determined as the effective diffusion coefficient (Deff) based on Fick’s second law of diffusion. Deff of O/R decreased with increases in the strength and elasticity of the composite film and relative humidity (RH) during film aging. Overall, the study showed that the salt-induced gelation method could be used to form an EA–CS composite film at room temperature. In addition to the strength and elasticity of the protein network, RH during aging could also provide a mean to regulate the controlled-release properties of such a composite film.

Preparation and structural properties of small‐particle cassava starch

AbstractAcid and enzyme hydrolyses followed by ball milling were applied to fracture cassava starch granules. Microscopic and chromatographic evidence suggested different mechanisms of the two hydrolyses. Using the enzyme process, granules with a sponge‐like structure and shells with the interior hydrolysed were produced. Amylose and amylopectin were subjected equally to multiple attacks by enzymes, with no significant change in granule crystallinity. The hydrolysed residues could not be effectively broken down by ball milling, although the crystallinity was destroyed. In contrast, the acid treatment caused superficial external corrosion, mainly at the amorphous lamellae, ie the branch points of amylopectin. Acid‐lintnerised starch granules were mostly of Degree of polymerization, DP 10–15 and exhibited increased crystallinity and brittleness, making them more susceptible to breakdown upon milling. Ball milling, although destroying some degree of crystallinity, could effectively reduce the size of acid‐hydrolysed starch, with no further degradation of amylodextrin molecules. By a combination of lintnerisation and ball milling, smaller particle starch (3–8 µm compared with 3–30 µm for native starch) could be produced. It is clear that removal of the amorphous phase prior to milling is critical for effective rupture of the granules. Copyright © 2003 Society of Chemical Industry

The influence of time and conditions of harvest on the functional behaviour of cassava starch—a proton NMR relaxation study

The extent of irrigation of crops in the field not only affects crop yield but also the functionality of the harvested product. This irrigation effect severely affects the processing response of starch harvested from Cassava and leads to industrial quality control problems. In this paper we show how the NMR transverse proton relaxation spectrum is a sensitive probe of the effect of irrigation on cassava starch functionality. The results suggest that increased irrigation results in a looser packing of the amylose and amylopectin chains in the cassava starch granule that facilitates their plasticization and gelatinization.