Cassava Starch Suspensions Research Articles

Synthesis of Periclase Phase (MgO) from Colloidal Cassava Starch Suspension, Dual Application: Cr(III) Removal and Pigment Reuse

Synthesis of Periclase Phase (MgO) from Colloidal Cassava Starch Suspension, Dual Application: Cr(III) Removal and Pigment Reuse

Structural analysis and adhesive capacity of cassava starch modified with NaOH:urea mixtures

In this research the interactions and structural changes induced by NaOH:urea mixtures on cassava starch suspensions as well as their adhesive capacity were studied. Cold gelatinization of 10–20% w/w cassava suspensions was induced by adding different NaOH:urea mixtures (0.5–2:1). Chemical modification of cassava starch was analyzed through optical microscopy as well as SEC-HPLC and size particle determinations, ATR-FTIR spectral and chemometric analysis were also carried out.Cassava starch treatment with NaOH:urea mixtures generated structural disorganization, induced cold gelatinization and promoted the hydrolysis of the polymeric chains. SEC-HPLC and ATR-FTIR results showed that the modifications induced in the adhesive formulations depend both on the starch content and the NaOH:urea ratio. All tested formulations exhibited adhesive capacity, being effective for Kraft paper substrate bonding. Thus, this simple and low-cost procedure was effective to chemically modify cassava starch allowing to obtain derivatives with tailor-made adhesive properties.

Continuous flow process to make fermented cassava starch substitute: I. Physicochemical and functional properties

Abstract The Brazilian fermented cassava starch (polvilho azedo) is prized as a raw material for fast food preparation. Its traditional production by natural fermentation and exposure to sunlight favors contamination and impurities, in addition to depending on the climate. The literature explains the characteristic expansion of polvilho azedo as a reaction of the lactic acid produced during fermentation and sun radiation. With the aim to evaluate a commercial continuous flow process, a modular lamp (UV-C) was evaluated to substitute exposure to sunlight. The selected doses were 1,000, 5,000 and 10,000 Joules per liter (J l-1). Native cassava starch suspension in water at 6% (dry basis) was adjusted to 4% lactic acid (dry basis) and exposed to UV-C radiation: (a) without lactic acid, (b) with lactic acid reaction for 1 hour, (c) with ultraviolet radiation, in addition to the combination of (ac) and (bc). The results showed that only the combination of acidification and ultraviolet radiation (bc) allows an expansion (11 cm3 g-1) higher than the commercial polvilho azedo (8.24 cm3 g-1) adopted as standard. It was concluded that is possible to achieve a substitute for fermented cassava starch by acidification of native cassava starch with lactic acid in a continuous flow system starting with a dose around 5,000 J l-1 of UV-C radiation.

Delayed and stable flow-DST behavior for granular starch suspensions

• The rheological behavior of cassava starch suspensions in glycerol was studied. • The presence of plastid membranes was verified for commercial cassava starch. • A deformable particle behavior was evidenced for starch granules in suspension. • Removal of the plastid envelope influenced delayed shear-thickening events. • Data allow distinguishing when a Newtonian or a shear thinning behavior precedes shear-thickening. Starch is synthesized in intracellular structures called amyloplasts, whose wraps delimiting the organelle are referred to as plastid membranes. Such envelopes are generally removed in the industrial processing of cereal starches, but not of cassava starch (CS), which is submitted to a different process. The occurrence of different rheological behaviors before a shear thickening (ST) event for granular starch suspensions is well known, but not yet thoroughly explained. The objective of this work was to study physical changes on commercial CS suspensions that could intensify their shear thickening properties when glycerol is used as a solvent. The results show that the removal of plastid envelopes from starch granules significantly reduces its deformable character in glycerol suspensions. It intensifies the delayed ST behavior and maintains the flow stability during an eventual discontinuous ST transition, provided that suspensions are conditioned at an adequate relative humidity (close to 43%). Experimental data also have suggested an explanation for why a Newtonian or a shear-thinning behavior precedes shear thickening in starch suspensions.

Alkali-treated starches as a new class of templates for CaCO3 spherulite formation: Experimental and theoretical studies

Biomineralization is the study of minerals produced by biomaterials or living organisms, and it has attracted considerable attention in industry and fundamental research. Here, for the first time, the roles of alkali-treated mung bean (MB) and cassava (CS) starches as templates for calcium carbonate (CaCO3) spherulite formation were investigated by bulk rheology and molecular dynamics (MD) simulations. The rheological results, including yield stress, flow behavior index, consistency coefficient, and hysteresis area of alkali-treated MB and CS starch suspensions containing Ca2+, revealed that the Ca2+ induced the folding of starch chains via Ca2+ crosslinking, leading to aggregation of starch–Ca2+ complexes. After the starch films were fabricated from the suspensions, CaCO3 spherulites were observed inside the films. The size and number of the spherulites increased with increasing concentration of Ca2+ in the suspensions as a result of an increase in nucleation sites needed for spherulite growth. Moreover, to gain a deeper understanding of the interactions between Ca2+ and starch and of the formation of the nucleation sites for spherulite growth, MD simulations were performed. Our findings pave the way for the design of new biomaterial-based templates, which can efficiently control crystal shape and size of CaCO3.

Effects of preincubation on the gelatinization of cassava and corn starch suspensions containing sodium hydroxide as a main component of corrugating adhesives

Effects of the preincubation temperature and the caustic-ratio, the molar ratio of sodium hydroxide to starch glucose residue, on the gelatinization of cassava starch and corn starch suspensions were studied using differential scanning calorimetry in view of utilization for corrugating adhesives. The gelatinization temperature and enthalpy change of cassava starch suspensions after the preincubation at 30°C decreased as the caustic-ratio increased, similar to those of corn starch ones: The gelatinization starting temperature (Ts) decreased considerably more than the peak temperature and the conclusion temperature (Tc). Although Ts lowered and the width of gelatinization temperature expanded, compared with those of corn starch suspensions, the two starch suspensions with the same half gelatinization transition temperature showed similar gelatinization characteristics of almost the same Ts and Tc. During 1 h-preincubations at 30°C–50°C, the starch granules with Ts that were lowered considerably below each preincubation temperature by sodium hydroxide showed limited gelatinization. The gelatinization transition did not rapidly spread over the whole suspension, but progressed stepwise in response to the increase of the causticratio and the rise of the preincubation temperature. In a prolonged preincubation at a constant temperature, Ts gradually rose at higher caustic-ratios in which stepwise gelatinization commenced. Although the starch gelatinization was irreversible and not in a stable equilibrium state for a long time, we concluded that such stepwise gelatinization progress controlled the practical preparation and use of corrugating adhesives.

Ultrasound Pre-treatment for Intensification of Hydrothermal Process in Reducing Sugar Production from Cassava Starch

Cassava is an abundant natural resource in Indonesia and mostly used as food. Starch, as the main component of cassava, can be converted to many of its derivative product such as glucose, fructose, and other reducing sugar. Conventionally, reducing sugar is produced from starch by acid and enzyme hydrolysis. A hydrothermal process is sophisticated biomass processing method which makes it possible to hydrolyze the starch by water only. However, the reducing sugar productivity of the hydrothermal process still not as high as the conventional process. By ultrasound pre-treatment, a hydrothermal process can be intensified, so that increase its productivity. This study set out to find the effect ultrasound pre-treatment to intensify production of reducing sugar from the hydrothermal process of cassava starch. The experiment was conducted by treating cassava starch suspension using ultrasonic irradiation with various operation time (0-120 minutes) and under a temperature of 40°C. For combination process, the starch suspension is processed under 15 minutes ultrasonic irradiation at 40°C, then continued to the hydrothermal process at 100°C and 100 bar using carbon dioxide as the pressurizing gas. The research found that the combination process can produce 0.693 mg/mL of reducing sugar

Sustainable panels design based on modified cassava starch bioadhesives and wood processing byproducts

This work was focused on the development of ecofriendly adhesives from cassava starch modified by polycarboxylic acids evaluating their performance in the design of sustainable panels using wood by-products. Additionally, a deep insight on the adhesive-substrate interactions was carried out through ATR-FTIR studies.Bioadhesives were formulated with cassava starch suspensions (5% w/w) modified with the addition of 0–80% (polycarboxylic acid weight /100 g starch) citric acid (CA) or 1,2,3,4 butane-tetracarboxylic acid (BTCA) and loaded with native starch at 5% (w/w) as filler. Formulated adhesives presented a pseudoplastic behavior. Panels were obtained from blends of wood processing byproducts (medium-density fiberboard -MDF) and the formulated bioadhesive by thermo-compression, optimizing the processing conditions. ATR-FTIR and SEM studies revealed the substrate-adhesive interactions and the affinity between the components. The stress values increased with BTCA concentration being 19 MPa for 80%, demonstrating the better cross-linking capacity of this acid compared to CA (11 MPa). Crosslinking and plasticizing effects were occurring in panels containing CA, depending on its concentration, as was confirmed by both puncture assays and contact angle. Thus, it was possible to obtain sustainable panels based on an eco-compatible adhesive, with distinguishable characteristics by tailoring both, the formulations and the processing conditions.

Particle Size Distribution Effect on Cassava Starch and Cassava Bagasse Biocomposites

Regarding the growing interest in the development of biodegradable films from renewable sources, this work is focused on the utilization of cassava roots bagasse as a natural filler of cassava starch films. Homogenous films could be obtained by casting molding from gelatinized cassava starch suspensions, plasticized with glycerol and containing 1.5% w/w bagasse. In order to study the particle size effect on films properties, three different fibrous residue fractions (particles sized between 500–250, 250–53, and particles <53 μm) were used and compared to films reinforced with bagasse particles sized under 500 μm. Chemical composition and particle size distribution of cassava bagasse helped to explain the starch films morphology and mechanical and barrier properties modifications. SEM micrographs evidenced that the filler was structurally incorporated in the matrix, reinforcing cassava–starch matrices regardless of bagasse particle size. The filler increased the UV-barrier capacity and opacity of the mater...

Cassava (Manihot esculenta) starch films reinforced with natural fibrous filler

The remaining fibrous residue of cassava starch extraction was characterized and used as film filler in order to obtain an enhanced fully biodegradable starch-based composite. Film-forming gelatinized cassava starch suspensions increased significantly their apparent viscosity and storage modulus with filler addition, although no segregation of filler particles was observed. Homogenous films were obtained from 3% w/w cassava starch film-forming suspensions including glycerol as plasticizer and the remaining fibrous residue. Plasticizer concentration was optimized in reinforced starch films. SEM micrographs evidenced that the filler was structurally incorporated in the matrix, although concentrations of 3% led to more heterogeneous surfaces because of the presence of large size filler particles. Reinforced films exhibited UV-barrier capacity and adequate water vapor barrier properties (14.6±0.710−11g/msPa) and tensile strength (18.01±0.19MPa) when 25% w/w glycerol was added as plasticizer. Filler addition reinforced the starch matrix increasing its mechanical resistance: 1.5% residue content increased over 900% the films elastic modulus. Furthermore, the obtained eco-compatible materials could be heat sealed, which indicates their suitability for packaging development. In conclusion, an integral approach to cassava roots use has been proposed, expanding its scope and providing added value to the remaining residue of starch extraction.

Use of biofilm in the postharvest conservation of 'Pedro Sato' guava

This present work aimed to assess the effect of different concentrations of cassava starch, associated or not with prochloraz fungicide, on the postharvest conservation of 'Pedro Sato' guavas. Physiologically mature fruits were immersed in a solution of prochloraz (49.5 g/100 liters of water) for 5 min. Fruit treated with distilled water and air dried were used as control. They were immersed in cassava starch suspension at concentrations of 0, 20, 30 and 40 g/L, plus 0.5 mL/L of mineral oil. The fruits were stored at 21.0 ± 1.0 ºC and relative humidity of 85 ± 5%, for 12 days, and were examined at every three days. The combination of prochloraz and cassava starch resulted in delayed loss of firmness and yellowness and inhibited the incidence of lesions caused by Colletotrichum gloeosporioides during the 12 days of storage. Fruits treated with 40 g/L of starch, whether containing prochloraz or not, had unpleasant taste and odor, which suggests the occurrence of fermentation. Control fruits, with and without prochloraz, and those treated with starch with no prochloraz, had nearly 100% lesion occurrence within the 12 days. Starch suspension of 30 g/L, containing prochloraz, was the most effective in maintaining fruit quality.

Effect of Cassava Starch Coating on Quality and Shelf Life of Fresh‐Cut Pineapple (Ananas Comosus L. Merril cv “Pérola”)

This research studied the influence of treatment with ascorbic acid, citric acid, and calcium lactate dipping and cassava starch edible coatings on quality parameters and shelf life of fresh-cut pineapple in slices during 12 d at 5 °C. After previous tests, the treatments selected for this study were samples dipped into antibrowning solution with 0.5% of ascorbic acid and 1% of citric acid, with and without 2% of calcium lactate and coated with 2% of cassava starch suspensions. Changes in weight loss, juice leakage, mechanical properties (stress at failure), color parameters (L* and H*), ascorbic acid content, sensory acceptance, and microbial growth of fruits were evaluated. Samples only treated with antibrowning agents were used as control. Edible coatings with and without calcium lactate were efficient in reducing weight loss, juice leakage, and maintaining firmness during storage. However, these samples showed more browning and the ascorbic acid content was reduced. All treatments presented good sensory acceptance (scores above 6). The determining factor of shelf life of pineapple slices was the microbial spoilage. A shelf life of 8 d was obtained for pineapple slices only treated with antibrowning agents. On the other hand, coated samples showed a reduced shelf life of 7 d and higher yeast and mold growth. Thus, although cassava starch coatings were efficient in reducing respiration rate, weight loss, and juice leakage and maintained mechanical properties, these treatments were not able to increase the shelf life of minimally processed pineapple. Practical Application: Pineapple fruit is highly appreciated for its aroma, flavor, and juiciness, but its immediate consumption is difficult. Therefore, pineapple is a potential fruit for minimal processing. However, shelf life of fresh-cut pineapple is very limited by changes in color, texture, appearance, off-flavors, and microbial growth. The use of edible coatings as gas and water vapor barrier and antibrowning agents can extend the storage time and maintain the quality of fresh-cut produce. Cassava starch and alginate coatings are alternative to preserve minimally processed pineapples without changing the quality parameters of fresh fruit. Thus, this study is useful for consumers and fresh-cut industry interested in knowing factors affecting shelf life and quality of fresh-cut pineapple.

Drying of Starch Suspension in Spouted Bed with Inert Particles: Physical and Thermal Analysis of Product

Drying in a spouted bed with inert particles promotes high heat and mass transfer rates due to the gas–solid contact, which in turn is successfully achieved by particles' cyclic movements. Because of its advantages and versatility, spouted bed drying of suspensions on inert particles is a potential alternative to flash and spray drying and has received attention in research and development in recent years. In this context, this article describes the drying process of cassava starch suspension (35% initial solids content) in a laboratory-scale cone-cylindrical spouted bed dryer with polypropylene particles. The setup consists of a cone-cylindrical spouted bed dryer (internal angle of 60°, 20-cm column diameter, and 5-cm inlet orifice diameter) with top feeding of suspension, which is sprayed by a double-fluid atomizer. The study focused on the fluid dynamics of polypropylene particles at inlet air temperatures of 60, 75, and 90°C and the effects of air temperature on dried starch properties, such as gelatinization temperature, pasting temperature, particle size distribution, crystalline profile, and final moisture content. The pressure drop fluid dynamic curves did not allow a proper analysis and assessment of minimum spout air flow when air was atomized in the bed. Therefore, the minimum spout air flow was determined by the visual observation of the fountain height in this case. Inlet air temperatures did not show a significant difference in the minimum spout air flow, but the bed presented dynamic instability with increasing inlet air temperature. The results showed that the spout fluid dynamic regime during drying was stable with air flow around 1.5 times the minimum spout air flow in the range of inlet air temperature studied. Drying air temperature influenced final moisture content of samples, which was lower than 13% for all conditions. However, physical properties of dried starch were not affected by process conditions.

Rheological properties of dilute aqueous solutions of cassava starch

The effects of starch concentration on the rheological properties of dilute aqueous solutions of cassava starch were investigated. Cassava starch suspensions at different starch concentrations (0.2, 0.4, 0.6, 0.8, and 1.0 wt. %) were heated at 90 °C for 1 h and then rapidly cooled to 25 °C. The apparent viscosities of starch solutions were measured as a function of starch concentration. The cassava starch solution with a concentration of 0.2% showed Newtonian behavior, and as the concentration was increased beyond 0.4%, the solutions showed shear-thinning behavior. The flow behavior (apparent viscosity against shear rate) of the solutions was well described using a power law model. The consistency indices increased and the flow behavior indices decreased with the increasing of starch concentration. After storing the solutions at 25 °C for 24 h, precipitation of starch took place instead of gelation. The volume of precipitation bed increased linearly with starch concentration.

Effect of High-Pressure Homogenization on the Structure of Cassava Starch

Cassava starch suspension was homogenized at different pressures (0, 20, 40, 60, 80, and 100 MPa) with a high-pressure homogenizer. To investigate the effect of high-pressure homogenization on the structure of cassava starch, the samples were characterized using microscopy, laser scattering, and X-ray diffraction techniques, with native and heat gelatinized cassava starches as controlled samples. The temperature of starch suspension increased linearly with applied pressure at a rate of 0.187°C/MPa. Microscopy studies showed that cassava starch was partly gelatinized after high-pressure homogenization, and the degree of gelatinization increased with homogenizing pressure. Results of laser scattering measurements suggested a considerable increase in particle size after homogenization at 100 MPa as a result of granule swelling. The X-ray diffraction pattern showed that there was no evident change after homogenization suggesting that the crystalline structure of starch granules was resistant to high-pressure homogenization.

Investigation on modification of cassava starch using active components of ginger roots (Zingiber officinale Roscoe)

Effects of ginger grates at concentrations of l, 5 and 20 g per 150 g of cassava starch suspension in 200 ml of water at room temperature were investigated in order to evaluate the potentials of active components of the ginger in modifying pasting and some physicochemical properties of the starch. Pasting properties of the ginger modified cassava starch showed high peak viscosities (487.58 - 420.25 RVU) compared to low peak viscosity (392.33 RVU) of the native starch. The modified starch was characterized with low set back viscosities (64.14 - 57.05 RVU) in relation to native starch with high set back viscosity (66.58 RVU). Similarly, the ginger modified starch was characterized with low gelatinization time (3.45 - 3.36 min) compared to the native starch with high gelatinization time (3.5 min). Ginger modified starch showed high swelling power (12.9 - 9.5) and solubility indices (11.3 - 15.6%) compared to native starch with low swelling power (8.9) and solubility index (3.1%). Therefore active components of ginger root can be used as natural modifying agents for cassava starch.

Investigation on modification of cassava starch using active components of ginger roots (Zingiber officinale Roscoe)

Effects of ginger grates at concentrations of l, 5 and 20 g per 150 g of cassavastarch suspension in 200 ml of water at room temperature were investigated in order to evaluate the potentials of active components of the ginger in modifying pasting and some physicochemical properties of the starch. Pasting properties of the ginger modified cassava starch showed high peak viscosities (487.58 - 420.25 RVU) compared to low peak viscosity (392.33 RVU) of the native starch. The modified starch was characterized with low set back viscosities (64.14 - 57.05 RVU) in relation to native starch with high set back viscosity (66.58 RVU). Similarly, the ginger modified starch was characterized with low gelatinization time(3.45 - 3.36 min) compared to the native starch with high gelatinization time (3.5 min). Ginger modified starch showed high swelling power (12.9 - 9.5) and solubility indices (11.3 - 15.6%) compared to native starch with low swelling power (8.9) and solubility index (3.1%). Therefore active components of ginger root can be used as natural modifying agents for cassava starch. Key words: Cassava starch, ginger root, modification, pasting properties.

Um dispositivo simples para a determinação simultânea e contínua da densidade de líquidos e da concentração de suspensões líquidas

Um dispositivo para a determinação automática da densidade e da concentração de partículas em suspensões líquidas foi desenvolvido, usando suspensões de amido de mandioca como modelo. As determinações das propriedades foram baseadas na medição da força de empuxo que a suspensão líquida exerce sobre uma bóia de plástico esférica, submersa na mesma e conectada a um sistema eletrônico de medição de força. Os resultados obtidos mostraram que o dispositivo é um excelente densímetro e pode ser usado com sucesso para a determinação da concentração de suspensões líquidas de partículas, quando a relação entre concentração de sólidos e a densidade da suspensão é conhecida. Resultados da medida de densidade de líquidos com o dispositivo, como o glicerol com 99% de pureza e um óleo de soja comercial ficaram muito próximos dos valores citados na literatura e medidos por picnometria.

Effects of biofilm and refrigeration on acerola postharvest conservation

The objective of this work was to compare the effects of four different concentrations of cassava starch film and storage temperature on shelf life and the quality of a genotype of acerola from the Germplasm Active Bank (GAB) of Federal Rural University of Pernambuco, Brazil. Sound orange-reddish acerola fruits were washed with a chlorine solution (100 mg.L-1 active chlorine) and randomly distributed into different lots. The fruits were dipped for 3 min in a cassava starch suspension with concentrations of 1, 2, 3 and 4% (w/v) and the control without coating, stored at 10ºC (85% RH) and 22ºC (85% RH). The total soluble solids (TSS), pH, titratable acidity (TA) and ascorbic acid (AA) were determined at harvest and regular interval during storage. The use of cassava biofilm at 1% on acerola fruits maintained the highest ascorbic acid content and the temperature of 10ºC extended storage life. The fruits coated with 1 and 2% biofilm could be stored for a period up to 15 days at 10ºC, with acceptable quality characteristics.

Kinetics of cassava starch hydrolysis with Termamyl(R) enzyme.

Kinetic properties of Termamyl(R) 120L were investigated with respect to starch hydrolysis in a batch reactor at substrate concentrations of 50-270 g. dm(-3) and enzyme concentrations of 0. 17-1 cm(3). dm(-3) (i.e., cm(3) of Novo Nordisk enzymatic solution per dm(3) of raw cassava starch suspension). A general kinetic expression giving product concentration as a function of time was first developed; an equation relating the reaction rate of each product to the sum of the concentrations of oligosaccharides with a higher degree of polymerisation was then derived. The empirical model satisfactorily fits experimental data for oligosaccharides with a degree of polymerization ranging from 1 to 7.