Modified Starch Concentrations Research Articles

Production and Evaluation of Hydroxypropyl Starch as a Viscosifying Agent for Enhanced Oil Recovery

AbstractIn this study, starch was obtained from rice wastes and the maximum extraction yield was 90.95 %. Chemical modification reactions were carried out by hydroxypropylation to obtain a modified starch extract, named 005A, soluble in synthetic injection brine. Extract 005A had a modified starch concentration of 1.24 %, with a pseudoplastic rheological profile and viscosities of 325.54 cP and 121.03 cP at temperatures of 25 and 60 °C, respectively. The application of extract 005A was evaluated by injectivity/filterability tests, which indicated a good filtration rate and viscosity loss of 3.81 % when passing the fluid through the filtering membrane. Stability tests indicated that the 005A extract had a viscosity loss of 21.35 %, at the temperature of 60 °C, after 60 days. The application of this extract enabled additional mineral oil recovery of 12.19 % in simulated core flooding tests. Therefore, the extract of hydroxypropyl starch is a promising viscosifying agent for Enhanced Oil Recovery (EOR) fluids.

Improving the Characteristics of Edible Film Using Modified Cassava Starch Over Ethanol Precipitation

Cassava starch has been widely explored as film forming material, however its hydrophilicity restricts its application. Hydrophobic material such as modified starch can be used in the film elaboration to improve its quality. This study aims to examine the effect of modified cassava starch concentration on the physical, barrier, and mechanical properties of edible films. A completely randomized design was used with 5 concentrations of modified starch at 0%, 5%, 10%, 15%, and 20% and 4 repetitions to obtain a total of 20 experimental combinations. The ANOVA showed that the modified starch concentration affected the compressive strength, thickness, transparency, and solubility of the edible film, but has no effect on its water vapor transmission rate (WVTR). Usage of 20% modified starch gave the product with the best characteristics at 0.22 mm thickness, 89.45 N/m2 strength, 6.484%/mm transparency, 52.19% solubility, and 21.00 g/m2.hour WVTR.

Experimental Study of Bentonite-Free Water Based Mud Reinforced with Carboxymethylated Tapioca Starch: Rheological Modeling and Optimization Using Response Surface Methodology (RSM).

Drilling mud’s rheological characteristics, such as plastic viscosity and yield point, are adversely affected with an inappropriate mud formulation. Native starch is one of the most important components in water-based mud because it improves the rheological and filtration characteristics of the mud. The native starch stability under various temperature and exposure time regimes is an important concern for utilizing starch in oil and gas drilling operations. In this work, tapioca starch was modified using carboxymethylation for the first time in order to improve its performance in non-damaging water-based muds. The modified starch was characterized by Fourier-transform infrared spectroscopy and X-ray diffraction. The thermal stability was tested using thermal gravimetric analysis. Various mud blends were formulated based on the experimental design using response surface methodology (RSM) to investigate their performance at various temperature conditions. Thirty experimental runs were carried out based on the selected factors and responses considering the optimal (custom) design, and the results were analyzed through ANOVA. The Fourier-transform infrared spectroscopy and X-ray diffraction results confirmed the carboxymethylation of starch. The TGA analysis revealed strong thermal stability after modification. Additionally, the Power law model (PLM) described the obtained rheological data for the selected formulations, resulting in determination coefficients of more than 0.95. Furthermore, the examined samples showed a reduction in the flow behavior index from 0.30 to 0.21 and an increase in the consistency index from 5.6 to 15.1. Optimization and confirmation results revealed the adequacy of the generated empirical models for both plastic viscosity and yield point. The obtained consistency index values provided a direct relationship with the modified starch concentration, indicating an improvement in the cutting carrying capacity of mud. Based on the current literature survey, the studied formulation has not been reported in the literature.

Evaluation of starch propionate as emulsion stabiliser in comparison with octenylsuccinate starch

Starch propionate (SP) with a degree of substitution (DS) of 0.21 was produced and its ability to stabilise emulsion was studied and compared with a commercial octenylsuccinate (OSA) starch (DS 0.03). The intrinsic viscosity values of SP and OSA were 0.9018 and 0.2514 (100 mL/g), respectively. Three different concentrations of SP and OSA at 12, 14 and 16 g/100 g of water phase and two different concentrations of oil at 35 and 45 g/100 g of water and oil phase were evaluated. Rheological properties, particle size and creaming index were assessed. Both SP and OSA emulsions produced shear thinning curve. Increase in concentration of starch stabilisers led to the increase in yield stress and apparent viscosity. SP emulsions demonstrated a significantly higher yield stress and apparent viscosity compared to OSA emulsions. SP emulsion showed G′> G″ values but OSA emulsions exhibited G″>G′ throughout the whole frequency range. As modified starch concentration increased, mean droplet diameter (d32) decreased. All SP emulsions were stable when stored at room temperature for 14 days. SP has great potential to be used in the preparation of cream-type emulsion such as mayonnaise, dermatological creams and cosmetic products.

Spray drying of babassu coconut milk using different carrier agents

ABSTRACTThe objective of this work was to optimize the spray drying of babassu coconut milk, an oil-in-water emulsion extracted from babassu kernels, using maltodextrin 10DE and modified starch as the carrier agents. Two central composite rotatable designs were used to verify the effect of the inlet air temperature and carrier agent concentration on process performance (process yield and outlet air temperature) and the physicochemical properties of the powder (moisture content, water activity, hygroscopicity, and lipid oxidation). Powders obtained under optimized conditions (25% maltodextrin concentration and 188°C, and a modified starch concentration of 20% and 170°C) were evaluated according to their morphology, particle size distribution, bulk and absolute densities, porosity, wettability, and thermal analysis.

Investigation and modelling of natural convection and conduction heat exchange: study on food systems with modified starch by means of computational fluid dynamics

SummaryThis study is focused on the effects of starch gelatinisation on heat exchange in food systems containing four modified starch concentrations (0, 2, 6 and 10%). Viscosity profiles of samples were experimentally measured: the effect of gelatinisation was evident, particularly at 6% and 10%, where the viscosity increased from 0.010 to 70 Pa s and to 1507 Pa s, respectively. The heat exchange rate showed a decrease with the increasing of starch concentration, and the effects were observed until 6%. Four Computational Fluid Dynamics (CFD) models were also developed, experimentally validated (RMSE < 1.5 °C) and used to study the heat exchange. Velocity profiles showed that the convective flows slowed down from 2.5 to 0 mms−1 after the gelatinisation. Finally, the effects on the slowest heating/cooling zone (SHZ/SCZ) location in the CFD models were studied: at 0% and 2%, the SHZ settled 15 and 80 mm from the bottom of jars in heating and cooling phase, respectively. At 6% and 10%, before the starch gelatinisation phase, the SHZ was located in a similar position of the 0% and 2% while when the gelatinisation occurred the SHZ slightly moved towards the geometric centre (50 mm) as for an only‐conductive product.

Effect of hydrocolloid on rheology and microstructure of high-protein soy desserts.

Due to the rheological and structural basis of texture perceived in semisolid foods, the aim of this work was to study the effects of two thickening agents, on rheology and microstructure of soy protein desserts. As rheological parameter values may not be enough to explain the possible perceived texture differences, the effect of composition on two instrumental indexes of oral consistency (apparent viscosity at 50s(-1) and complex dynamic viscosity at 8Hz) was also studied. Samples were prepared at two soy protein isolate (SPI) concentrations (6 and 8% w/w), each with four modified starch concentrations (2, 2.5, 3 and 3.5% w/w) or four Carboxymethyl cellulose (CMC) concentrations (0.3, 0.5, 0.7 and 0.9% w/w). Two more samples without added thickener were prepared as control samples. The flow curves of all systems showed a typical shear-thinning behaviour and observable hysteresis loops. Control sample flow fitted well with the Ostwald-de Waele model and the flow of samples with thickener to the Herschel-Bulkley model. Viscoelastic properties of samples ranged from fluid-like to weak gel, depending on thickener and SPI concentrations. Starch-based samples exhibited a globular structure with SPI aggregates distributed among starch granules. In CMC-based samples, a coarse stranded structure with SPI aggregates partially embedded was observed. Variation of the two thickness index values with composition showed a similar trend with good correlation between them (R(2)=0.92). Soy desserts with different composition but with similar rheological behaviour or instrumental thickness index values can be obtained.

Microencapsulation of Swiss cheese bioaroma by spray-drying: Process optimization and characterization of particles

In this study, the microencapsulation of Swiss cheese bioaroma through spray drying was examined. The fermented whey permeate (bioaroma) produced by Propionibacterium freudenreichii was characterized and used as active for microencapsulation process using spray drying. The effect of inlet air temperature drying (Ti), and modified starch concentrations (% MS) was evaluated using the response surface methodology to examine the physical, chemical and morphological properties of various microparticles produced. The rheological analysis of suspensions prepared with different concentrations of modified starch in maltodextrin combination showed that Newtonian model was appropriate to describe the characteristics of flow. It was found that greater retention of acetic and propionic acids was obtained with intermediate air inlet temperature and modified starch concentrations (175°C; 50% MS), and the extreme values of the variables resulted low retentions. Lower values of moisture and water activity were obtained with 50% of modified starch, and the temperature influenced positively only in water activity of the microparticles. The bulk density and average particle diameter were positively influenced by the concentration of modified starch, and interaction of air inlet temperature and starch concentration only influenced the average diameter of the microparticles. The morphology of the particles had a spherical shape with diameters varying between microns and millimeters.

Microencapsulation of pequi pulp by spray drying: use of modified starches as encapsulating agent

The aim of this study was to evaluate the microencapsulation of pequi pulp by spray drying. A central composite rotational design was used in order to evaluate the effect of the independent variables: inlet air temperature, surfactant concentration and modified starch concentration. The dependent variables were assumed as yield of the process and the product features microencapsulated. A selection of the best process condition was performed to obtain the best condition of a product with the highest vitamin C and carotenoids content. Powders showed moisture content below 2%. The experimental values of hygroscopicity, yield, water activity, total carotenoids and vitamin C powders ranged from 7.96 to 10.67 g of adsorbed water/100g of solids, 24.34 to 49.80%, 0.13 to 0.30, 145.78 to 292.11 mg of ascorbic acid/g of pequi solids and 15.51 to 123.42 mg of carotenoids/g of pequi solids, respectively. The inlet air temperature 140°C, the surfactant concentration of 2.5% and the modified starch concentration of 22.5% was recommended as the selected condition. By the scanning electron microscopy, it was observed that most of the particles had spherical shape and smooth surface.

Effect of modified starch concentration and freezing and thawing rates on properties of mashed potatoes (cv. Kennebec)

AbstractEffects of modified cornstarch concentration, freezing rate and thawing mode on quality properties of mashed potatoes were examined. The product was tested by oscillatory rheometry, instrumental texture profile analysis (ITPA) and cone penetration, colour, dry matter (DM) and sensory analyses. Oscillatory parameters showed that increasing starch concentration resulted in a softer product in which gel strength decreased in direct proportion to concentration in quick‐frozen and microwave‐thawed product. Quick freezing made for firmer mashed potatoes, whereas oscillatory, ITPA and penetration parameters were lower in the samples thawed at 4 °C. Starch concentration and instrumental consistency and firmness were directly proportional to one another. Adding starch at the highest concentration, quick freezing and slow thawing produced a lighter‐coloured mashed potato, although the loss of colour in the processed product was not detected by panellists in the microwave‐thawed samples. DM was higher in the quick‐frozen samples and lower in air‐thawed samples. The factors studied affected different sensory texture parameters but had hardly any effect on attributes perceived during final and residual phases of mastication. Only starch concentration had a significant effect on sensory acceptability, but interactions between factors showed that starch addition followed by quick freezing was judged undesirable by the panellists due to excessive softening. Oscillatory parameters correlated well with sensory texture attributes and proved quite precise. They would therefore appear to be the best test to monitor properties of frozen mashed potatoes. Copyright © 2007 Society of Chemical Industry

Effect of added oil and modified starch on rheological properties, droplet size distribution, opacity and stability of beverage cloud emulsions

Optical and rheological properties of beverage cloud emulsions as a function of water-phase and oil-phase concentrations were investigated. The specific gravity of phases, particle size distribution and creaming stability of prepared emulsions in diluted forms were evaluated. Combinations of emulsions with added starch (3.74–18.7% w/w, with oil at 3.74% w/w) and oil (7.48–18.7% w/w with starch at 11.2% w/w) were used. The specific gravity of oil phase was adjusted using a constant combination of weighing agents [sucrose acetate isobutyrate and brominated vegetable oil] and different level of coconut oil. Oil-phase concentration had a significant effect (P<0.05) on increasing the opacity of emulsion. Increase in modified starch concentration for all water phases decreased the flow behavior index while oil phase at any given concentration of coconut oil contributed to a Newtonian behavior. Raise in viscosity of emulsions was more pronounced as oil concentration increased and shear thinning behavior of oil added emulsions was associated with droplet flocculation. Creaming in acidified sugar solution of 11°Bx and pH 3 was observed when the oil-phase specific gravity decreased and sedimentation occurred at the lower viscosity of water phase. Examination of dynamic rheological properties of emulsions revealed that all oil added emulsions showed viscous behavior with the delta degree (G″/G′) greater than 74 at maximum frequency level (50rad/s) and decreased along with increasing the oil level. The solid or elastic behavior was related to those emulsions that exhibited sedimentation with the delta degree lower than 35.

MODELIZACIÓN DE LA CONSISTENCIA DE YOGUR BATIDO: EFECTO DE LA ADICIÓN DE VARIOS GELIFICANTESMODELIZATION OF STIRRED YOGUR CONSISTENCY: ADITION EFFECT OF DIFFERENT THICKENINGSMODELIZACIÓN DA CONSISTENCIA DE IOGUR BATIDO: EFECTO DA ADICIÓN DE VARIOS XELIFICANTES

Apparent viscosity was used to fit a mathematic model for the yoghurt consistency and subsequently to determine in what extent it was influenced by three thickenings. Experimental yoghurt makings were done by varying the gelatin, pectin and modified starch concentrations. The apparent viscosity of each sample was determined. A sensory evaluation with trained judges was performed so as to correlate the apparent viscosity with the sensory evaluation of the consistency. The regrssion value shows that 97.8% of the sensory judgement variability is corectly exlained. The consistency was also correlated with the concentration (%) of the thickenings, thus obtaining an equation explaining 85% of the observed variation where starch was no significante and gelatin have the highest influence. The fit goodness of both regression equations was verified with four additional experiences, the percent variation coefficient between sensory and calculated consistency being less than 5%. This methodology turned up to be appropriate to predict the product consistency by using a simple rheological test and the thickening composition. © 2003 Altaga. All rights reserved. Resumen Se estudió la evaluación de consistencia en el yogur batido y su variación en función del agregado de concentraciones variables de almidón, gelatina y pectina de alto metoxilo. A tal fin se utilizó un diseño experimental de segundo orden, cuyas respuestas fueron la viscosidad aparente y un puntaje de consistencia, la cual fue evaluada en forma sensorial por un panel de jueces entrenados. Mediante análisis de regresión se seleccionó un modelo matemático para correlacionar ambas respuestas, con el cual se determinó para cada una de las condiciones experimentales del diseño un índice matemático de consistencia designado como Cμ. Finalmente se analizó la variación de Cμ. con la concentración de los diferentes gelificantes comerciales utilizados en la formulación del yogur batido, obteniéndose un modelo de regresión que explica el 85% de la variabilidad de consistencia observada. Los resultados indican que la concentración de gelatina es la de mayor influencia, siendo por el contrario no significativa la concentración de almidón. Se realizaron cuatro experimentos adicionales a fin de verificar la bondad del ajuste, obteniéndose coeficientes de variación menores al 5%. La metodología de evaluación propuesta permite, en las condiciones del estudio, predecir un índice matemático de consistencia del yogur batido mediante la determinación reométrica de viscosidad aparente. © 2003 Altaga. Todos los derechos reservados. Palabras clave: yogur, consistencia, gelificantes, evaluación sensorial. Resumo Estudiouse a avaliación da consistencia no iogur batido e a su variación en función do agregado de concentracions variables de almidón, xelatina y pectina de alto metoxilo. A tal fin utilizouse un deseño experimental de segunda orde, cuias respostas foron a viscosidade aparente e unha puntaxe da consistencia, a cal foi evaluada en forma sensorial por un panel de xuices entrenados. Mediante análise de regresión seleccionouse un modelo matemático para correlacionar ambas respostas, co cal determinouse para cada unha das condicións experimentais do deseño un índice matemático de consistencia designado como Cμ. Finalmente analizouse la variación de Cμ. coa concentración dos diferentes xelificantes comerciais empregados na formulación do iogur batido, obtivéndose un modelo de regresión que explica o 85% da variabilidade de consistencia observada. Os resultados indican que a concentración de xelatina é a de maior influencia, sendo polo contrario non significativa a concentración de almidón. Realizaronse catro experimentos adicionaies coa fin de verificar a bontade do axuste, obtivéndose coeficientes de variación menores ó 5%. A metodoloxía de avaliación proposta permite, nas condicions do estudio, predecir un índice matemático de consistencia do iogur batido mediante a determinación reométrica de viscosidade aparente. © 2003 Altaga. Tódolos dereitos reservados. Palabras chave: iogur, consistencia, xelificantes, avaliación sensorial.