Different Types Of Starch Research Articles

Microencapsulation of oregano essential oil in starch-based materials using supercritical fluid technology

Abstract Oregano (Origanum vulgare) essential oil (EO), besides its flavoring characteristics, is well known for its antioxidant, antimicrobial and anti-inflammatory properties, which make it a good alternative as food preservative from natural origin. Furthermore, it has been reported that oregano EO can be used as a health promoting substance in the prevention of neurodegenerative disorders. However, EO can be easily degraded by light, oxygen and temperature and there is still a lack of an adequate protection system to improve its stability along processing. In the present study, oregano essential oil was impregnated in microspheres of different types of starch using SSI (supercritical solvent impregnation) with supercritical carbon dioxide (sc-CO2). This process is characterized by mild operating conditions and inert processing atmosphere, especially adequate for the formulation of EOs. The quality of the final product and process efficiency was evaluated by the antioxidant activity (AA) of the final product, determined according to the ORAC assay. Different processing conditions were studied, such as pressure (8–15 MPa), temperature (40–50 °C), impregnation time (3–24 h) and mass ratio of essential oil/starch (0.4–3). The SSI is a batch process and the influence of mode of depressurization was also analyzed. Industrial relevance The present study demonstrates that supercritical impregnation is an attractive process for the impregnation of natural matrices, such as starch granules, with essential oils (EOs), namely oregano essential oil. The mild operating conditions avoid EO degradation and the high diffusivity of supercritical CO2 in the solid matrix (starch) guarantees a deep impregnation of the EO and high antioxidant activity of the product, also during storage. Further, the process is easy to scale up for the production of potential health-promoting ingredients for the food industry.

The structure and properties of different types of starch exposed to UV radiation: A comparative study

The effect of UV-irradiation on four different types of native starch (corn, waxy corn, wheat and potato) have been investigated. Although the changes in the chemical structure of starch specimens were small, indicating good photostability, the samples lost adsorbed water and their crystallinity degree decreased after irradiation. Moreover, a drop in average molecular weight occurred in samples (with the exception of potato starch) as a result of main chain scission. The variations in the properties of investigated specimens of various origin were related to the differences in their structure and macromolecular arrangement. The lowest photostability among the four starches was exhibited by potato starch.

Influence of xanthan transition on the rheological properties of waxy starches

The effects of xanthan gum on the properties of waxy starch systems were investigated with a particular focus on the conformational transition of xanthan. Different types of starches were used in this setup: maize, potato, chemically modified maize and rice. Under dilute conditions, xanthan gum and its transition did not affect the gelatinization of the starches. However, significant effects on the pasting behavior were observed, where the xanthan transition caused a significant reduction of the viscosity. It was demonstrated that xanthan can limit the breakdown of sensitive starch granules and that this effect might be enhanced by the xanthan transition. Flow curves of the cooled pastes showed that granule integrity is a prerequisite for optimal xanthan functionality, but the granule stabilizing effect of xanthan was too limited under these pasting conditions to significantly influence the flow behavior.

Interaction of cationic starch and dissolved colloidal substances from paper recycling, characterized by dynamic surface measurements

Modified starch with cationic as well as hydrophobic units can be used to remove negatively charged substances due to recycling processes of paper, so called stickies.The interactions between different types of starch and a negatively charged model suspension, obtained by heating up common newspaper, have been studied using polyelectrolyte titration, nephelometric turbidity measurement, and determination of the carbon content. In addition, we were able to show that the dynamic interface tension is a very suitable property to characterize the surface active compounds in the model suspension which allows receiving additional information about the sticky content of the waste water.Polyelectrolyte complexes were formed by adding cationic starch to the anionically charged model suspension. At a certain mixing ratio their precipitation leads to a significant reduction of the turbidity and the carbon content, whereas the surface tension increases due to sticky removal. Among starches with the same degree of cationic charge, those with the highest hydrophobicity were the most effective.

A novel multifunctional pharmaceutical excipient: Modification of the permeability of starch by processing with magnesium silicate

A directly compressible excipient has been developed by co-processing starch with magnesium silicate. The foregoing was achieved either by co-precipitation of magnesium silicate onto different types of starch or by dry granulation of maize starch with magnesium silicate. A variety of techniques (permeability, water retention/swelling, compression analysis, scanning electron microscopy, tensile strength and disintegration/dissolution studies) were used to characterize these systems. The permeability of the formulations produced using the two methods was evaluated experimentally using Darcy's permeability law. Magnesium silicate, as an anti-adhering agent, increases the permeability of both maize and partially pregelatinized starch, resulting in compacts of high mechanical strength, short disintegration time and low lubricant sensitivity. Such advantages are evident when the properties of the physical mixture of maize starch with magnesium silicate are compared with the co-precipitation and dry granulation techniques. Formulation with this novel excipient system, using paracetamol as a model drug, indicated its suitability as a single multifunctional excipient.

Comparison of the morphological, crystalline, and thermal properties of different crystalline types of starches after acid hydrolysis

AbstractA‐type maize starch, B‐type Fritillaria ussurensis, and C‐type Rhizoma dioscorea starches were hydrolyzed (32 days) with 2.2 N HCl. Regardless of the crystallinity level, starch with predominant B‐crystalline type was less susceptible to acid degradation than A‐type and C‐type starches, and initial rates of hydrolysis in B‐type was lower than others. The SEM and XRD results revealed that different types of starch displayed different hydrolysis mechanisms. The acid corrosion started from the exterior surface of A‐type and B‐type starches followed by the core of granules. However, the hydrogen ions primarily attacked the interior of the C‐type R. dioscorea starch granules and then the exterior. FT‐IR results confirmed that the amorphous regions in the starch granules were hydrolysed first. After 8–32 days of hydrolysis, the acid‐modified C‐type starch showed typical A‐type characteristics upon analysis of the XRD pattern. The average particle size of hydrolytic starch decreased with increasing hydrolysis time. The thermal results revealed that the hydrolytic starch showed lower ΔH than the native starch, while displaying higher peak width (Tc − To) value.

Development, relative retention, and fecundity of Tribolium castaneum (Herbst) on different starches

The development, relative retention, and fecundity of the red flour beetle, Tribolium castaneum (Herbst), on six different types of starches, flour, and flour plus yeast were investigated in the laboratory. The size of 90% of particles among the starches was below 15 to 58 μm, while that of the flour was below 133 μm. Larval length, head capsule width, and weight gain of T. castaneum were measured by rearing larvae on starches, flour, and flour plus 5% (by wt) Brewer’s yeast diet for 30 d at 28oC and 65% r.h. Larvae reared on flour or flour plus yeast developed normally and showed better survival compared to those reared on starches. Larvae on starches failed to develop beyond second and rarely third instars. Adults of T. castaneum did not show any preference to flour over starches in dual-choice tests. Tribolium castaneum laid less than 3 eggs/female over a 15 d period on all starches, but laid 97 and 109 eggs/female on flour and flour plus yeast diet, respectively. These initial studies suggest that starches are poor substrates for development, and currently experiments are in progress to improve larval survival and development by incorporating specific nutrients in starches. Starches were as attractive as flour to adults; however, starches do not appear to be a suitable medium for egg-laying. Preliminary experiments by moving adults between starches and flour and vice versa showed that feeding on suitable diets is essential for eliciting oviposition. Although preliminary, these interesting findings suggest that starches may have potential in managing development and reproduction of T. castaneum-a pest that is common and severe in food-processing facilities. Keywords : Nutritional control, Tribolium castaneum , Resistant starches, Development, Oviposition, Pest management

Properties of compatibilized polylactide blend films with gelatinized corn and tapioca starches

AbstractBlend films containing two types of starch, various amounts of methylenediphenyl diisocyanate (MDI), and polylactide were prepared. The effects of MDI level and starch type on the tensile, thermal, and morphological properties of these films were investigated. The MDI amount was varied from 0 to 10 wt % on the basis of gelatinized starch (GS) content, whereas two types of starch (corn and tapioca) were added as fillers. In this study, the blend films were hot‐mixed at 180°C by an internal batch mixer and then compression‐molded to form test specimens. The results show that the addition of MDI as a compatibilizer led to an increase in the tensile properties compared with the uncompatibilized films. Furthermore, the thermal properties indicated some improving interfacial adhesion between the two phases, as evidenced by the morphological results. These behaviors were observed in the blends with both gelatinized tapioca starch and gelatinized corn starch. The different types of starch had no effect on the glass‐transition and melting‐temperature shifts, including water absorption of the blend films. On the other hand, the mechanical properties of the blends with gelatinized corn starch were higher than those of the others. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Preparation and properties of polyhydroxybutyrate blended with different types of starch

AbstractThis study examines the properties of polyhydroxybutyrate (PHB) when blended with two types of maize starch, Starch 1 (containing 70% amylose) and Starch 2 (containing 72% amylopectin). The PHB/starch blends were prepared by melt compounding at a ratio of 70/30 by weight and characterized in terms of their morphology, structure, thermal, rheological, and mechanical properties. The results show that starch granules act as a filler in PHB/starch blends and also act as a nucleating agent causing a very significant reduction in the size of the PHB spherulites. There were found to be significant improvements in thermal, rheological, and mechanical properties, and these were greater for blends containing Starch 1 than those containing Starch 2. These improvements are attributed to enhanced hydrogen bonding between PHB and Starch 1 with high‐amylose content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Physicochemical and Functional Properties of Ozone-Oxidized Starch

The effects of oxidation by ozone gas on some physicochemical and functional properties of starch (corn, sago, and tapioca) were investigated. Starch in dry powder form was exposed to ozone for 10 min at different ozone generation times (OGTs). Carboxyl and carbonyl contents increased markedly in all starches with increasing OGTs. Oxidation significantly decreased the swelling power of oxidized sago and tapioca starches but increased that of oxidized corn starch. The solubility of tapioca starch decreased and sago starch increased after oxidation. However, there was an insignificant changed in the solubility of oxidized corn starch. Intrinsic viscosity [eta] of all oxidized starches decreased significantly, except for tapioca starch oxidized at 5 min OGT. Pasting properties of the oxidized starches followed different trends as OGTs increased. These results show that under similar conditions of ozone treatment, the extent of starch oxidation varies among different types of starch.

Characterization and optimization of extracellular alkaline lipase production by Alcaligenes sp. Using stearic acid as carbon source

The aim of this study was to improve the production of an extracellular alkaline lipase from Alcaligenes sp. (ATCC 31371) by optimization of the culture medium, for economic production of biodiesel from waste vegetable oil. A number of carbon sources including different types of starch, sugar, sugar alcohol, organic acids, and surfactants were investigated. Polyoxyethylene (20) sorbitan tristearate, whose side chain is stearic acid, was the most effective carbon source for lipase production. Box-Behnken experimental design was used for three factors (soy protein, sodium nitrate, and stearic acid) and the optimal composition for maximum lipase production (1.7-fold enhancement) was established as soy protein 4.07%, sodium nitrate 0.17%, and stearic acid 0.28% at 28°C with an agitation rate of 220 rpm for 24 h. The enzyme was purified to homogeneity and the recovery of the lipase activity was 7.8% with a 30-fold purification. The estimated molecular size of the protein determined by SDS-PAGE was 33 kDa. The optimum pH and temperature of the purified lipase was 8.5 and 40°C, respectively. The purified enzyme was stable in the pH range of 6.0 and 9.5 and in the temperature range of 20 and 50°C.

Thermal conductivity of porous alumina ceramics prepared using starch as a pore-forming agent

The thermal conductivity of porous alumina ceramics prepared using different types of starch (potato, wheat, corn, and rice starch) as pore-forming agents is investigated from room temperature up to 500 °C. The temperature dependence measured for alumina ceramics of different porosity (in the range 6–47%) is fitted with second-order polynomials and 1/ T-type relations, and compared to available literature data for dense alumina. It is found that the porosity dependence of the relative thermal conductivity k r = k/ k 0 is well described by a modified exponential relation of the form k r = exp(−1.5 ϕ/(1 − ϕ)), where ϕ is the porosity. This finding is in agreement with other literature data and seems to indicate a common feature of all porous materials with microstructures resulting from fugitive pore-forming agents.

Structure and Water Absorption of Starch and Polyethylene-Octene Elastomer Composites

Four modified starches, including gelatinized starch (GS), crosslinked starch (CS), oxidized starch (OS) and esterified starch (ES), were blended with polyethylene-octene elastomer (POE) at 20 wt% starch content. The graft copolymer POE-g-MAH acted as a compatibilizer where 5 wt% was added to POE and various starch blends. The crosslinked starch was blended with POE in different proportions and conditioned at various relative humidities (RH), 11%, 32%, 43%, 75% and 100%, respectively until equilibrium to study the water absorption of POE/starch blends. Although different types of starch were used, the mechanical properties of each POE/starch blend were not significantly different. The compatibilizer had an obvious influence on the morphology and mechanical properties of each POE/starch blend. The starch dispersed in POE matrix better and the interfacial adhesion between starch and POE phase improved after adding the POE-g-MAH, also the tensile strength of POE/starch blends increased. With increasing starch content, both the tensile strength and elongation at break of POE/CS blends decreased. The water uptake of POE/CS blends increased with increasing time and starch content. The POE/CS blends without compatibilizer had higher water uptakes than those samples with compatibilizer. After equilibrium at different RH, the tensile strength of POE/CS blends decreased as RH increased, but the elongation at break increased with increasing RH.

Optimization of Cyclodextrin Glycosyltransferase Production by Response Surface Methodology Approach

The aim of the study was to optimized cyclodextrin glycosyltransferase (CGTase) production using local isolated strain MK6 which was identified as Bacillus sp. Optimum activity obtained at temperature of 70 °C and the enzyme shows a wide range of pH stability ranging from 4-10 when stored at 4 °C for 24 h and temperature stability ranging from 30-80 °C at 1 h incubation period. The CGTase activity was even maintained at 0.4 U mL-1 at 90 °C for 40 min incubation. Prior to optimization of CGTase production, selection for the best carbon source through detection using modified phenolphthalein method containing different types of starch were performed. Sago starch gave significant result and was used for further optimization using statistical analysis namely Response Surface Methodology (RSM) approach. The optimal calculated values were 3.34% sago starch, initial pH of 10.15 and agitation speed of 187 rpm; with predicted activity of 2.07 U mL-1 of CGTase. These predicted optimal parameters were confirmed in the laboratory and the final CGTase activity obtained was very close to the predicted value of 2.56 U mL-1.

Statistical optimisation of some parameters affecting flocculation of Egyptian iron ore

Many tonnages of iron ores are mined annually. Upgrading of such ores is a prerequisite and a mandatory step before their further usage in subsequent purposes as for example in the blast furnace. According to the kind and nature of the ore associated impurities, its fineness and degree of liberation, the suitable processing technique will be selected. In this paper, upgrading of an Egyptian iron ore applying the selective flocculation approach was studied. Different types of starch were used as flocculants. The potato starch among the studied starches showed the best separation results. However, the results showed a fluctuation in the obtained concentrates grade and recovery. Therefore, statistical design of experiments, Box Behenken design, was used as an optimisation tool. The results of the design, applied to potato starch, showed that the iron grade up to 55% could be obtained as a preconcentrate. Regrinding of the preconcentrate to 100% less than 25 μm followed by selective flocculation at the design optimum conditions; a final concentrate with 61% Fe could be obtained.

EFEITO DO AMIDO SOBRE AS CARACTERÍSTICAS TEXTURIAIS DE HAMBÚRGUER DE PEIXE: ANÁLISE SENSORIAL E INSTRUMENTAL

O objetivo deste estudo foi avaliar o efeito do amido de diferentes origens botânicas na textura de hambúrguer de peixe (a base de surimi), mediante análises sensorial e instrumental, e correlacionar a informação sensorial com a instrumental. Três amostras de hambúrguer de peixe elaboradas com diferentes tipos de amido foram avaliadas por análise sensorial descritiva e análise instrumental. Em relação aos resultados de textura (instrumental), a formulação 3 (amido de mandioca modificado) foi caracterizada pelos atributos dureza, gomosidade e mastigabilidade. A análise sensorial realizada por equipe de 8 julgadores caracterizou as formulações 2 e 3 pelos atributos dureza e elasticidade. Verificou-se correlação positiva entre dureza (instrumental) e atributos sensoriais de textura, como dureza, elasticidade, gomosidade, mastigabilidade e fraturabilidade, contribuindo para a percepção da dureza durante a mastigação do hambúrguer de peixe.

Evaluation of the types of starch for preparation of LDPE/starch blends

This study evaluated in relation the growth, and the amylolytic activity of mixed and isolated cultures of Phanerochaete chrysosporium and Talaromyces wortmanni on different types of starch. The thermal and mechanical properties in polyethylene/starch blends (proportion: 80/20 (w/w) before and after inoculation of the mixed cultures were evaluated. The regular starch Amidex 3 and the modified starch Fox5901 stood out in relation to the cellular growth and production of the amylase enzyme. In spite of the short time that the blends were exposed to the fungi, the microorganisms promoted physical and chemical changes in the structure of the blend, modifying its thermal and mechanical properties. The alteration of the degree of crystallinity and mechanical properties of the blends could be indications of the modification caused by the biodegradation process.

Freeze‐thaw Stability of Gels Prepared from Starches of Non‐conventional Sources

AbstractStarch is an ingredient used in the formulation of several processed and frozen products, thus, evaluating the stability of gels of different types of starches when submitted to freezing and thawing is of great interest in order to guarantee the quality of the product at the end of the production and distribution chain. Stability of starch gels from non‐conventional sources, i.e. Peruvian carrot (arracacha), sweet potato, white bean and chickpea exposed to five cycles of freezing and thawing was studied by evaluating texture and syneresis. The results were compared to those obtained using commercial starches (native corn, waxy corn and modified waxy corn). The waxy corn and Peruvian carrot starch gels were stable until the third freeze‐thaw cycle studied. The sweet potato starch gel was stable until the second cycle, but presented low syneresis until the fourth freeze‐thaw cycle (2.9%). During the experiment, the Peruvian carrot starch gel lost 5% water at maximum, and the waxy corn and modified waxy corn, 8% and 12%, respectively. The native corn, chickpea and white bean starch gels presented high water losses already in the first cycle. As to texture, the sweet potato and Peruvian carrot starch gels presented greater hardness values than the waxy corn and modified waxy corn starch gels during the entire storage period studied. Until the fourth freeze‐thaw cycle, the modified waxy corn and Peruvian carrot starch gels showed no statistically significant alteration (p≤0.05) in gel hardness. After the first freeze‐thaw cycle, the hardness of the sweet potato starch gel was constant. The same occurred with the gels obtained from chickpea and white bean.

Microwave processing of starch‐based porous structures for tissue engineering scaffolds

AbstractA novel microwave (MW) processing technique was used to produce biodegradable scaffolds for tissue engineering from different types of starch‐based polymers. Potato, sweet potato, corn starch, and nonisolated amaranth and quinoa starch were used to produce porous structures. Water and glycerol were used as plasticizers for the different types of starch. Characterization of the pore morphology of the scaffolds was carried out with scanning electron microscopy. Three‐dimensional structures with variable porosity and pore size distribution were obtained with the MW foaming technique. The amount of remaining water in the scaffolds and their corresponding densities showed important variations among the different types of starch. Compressive mechanical properties were assessed by indentation tests, and a strong dependence of the indentation stress on the average pore size was found. Studies in simulated body fluid were used to assess the in vitro bioactivity, degradability, and surface topology evolution in the scaffolds. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1332–1339, 2007

Enzyme catalysis of insoluble cornstarch granules: Impact on surface morphology, properties and biodegradability

Granular cornstarch was treated with microbial glucoamylase (50 mM sodium acetate buffer at pH 5.5 at 30 °C, 150 rpm) for up to 8 h. Treated starch was recovered and evaluated for changes in granular morphology, chemical properties, thermal properties, crystallinity and impact on its biodegradability. As the enzyme treatment progressed, reducing sugars began to accumulate in the liquid culture media (total of 6% in 8 h) and the granule suffered roughly 6% weight loss within 8 h of incubation. While the granules appeared intact morphologically, numerous small pits developed throughout the surface of the granules as a result of the enzyme treatment. Even after 8 h of enzyme treatment, the pitted granules were not disrupted and remained intact. X-ray diffraction indicated no loss of crystallinity in the enzyme treated granules but rather an increase in relative crystallinity, suggesting that the enzyme preferentially catalyzed the anhydroglucose units in amorphous regions of the granule. These findings were further supported by FTIR data suggesting that granules become more resistant to enzyme attack as amorphous amylose is hydrolyzed faster than the crystalline amylopectin domains. These results also suggest that variations in the crystallinity of different types of starches have the potential to affect their rates of biodegradation. Enzyme treated starch granules exhibited resistance to biodegradation, and the degree of resistance was related to the length of enzyme treatment. Granules treated with enzyme for a total of 7 h and subjected to biodegradation in soil produced 40–50% less CO 2 in a closed circuit respirometer compared to the untreated samples. Differential scanning calorimetry (DSC) thermograms showed an endothermic reaction with little change in the onset and peak temperatures indicating that glucoamylase started by degrading the starch granules from the surface.