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Nataricha Phisarnchananan - One of the best experts on this subject based on the ideXlab platform.
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whey protein microgel particles as stabilizers of Waxy Corn starch locust bean gum water in water emulsions
Food Hydrocolloids, 2016Co-Authors: Brent S Murray, Nataricha PhisarnchanananAbstract:Abstract Food-grade whey protein isolate (WPI) microgel particles were investigated as a particle stabilizer of water-in-water (W/W) emulsions. The microgel particles were produced via the novel method of forcing coarse particles of a pre-formed thermally processed WPI protein gel through a jet homogenizer. The Z-average particle size was 149 ± 89 nm but the particles showed a strong tendency for aggregation when the pH was lowered from pH 7 to 4, when the zeta potential also switched from −17 to +12 mV. The viscoelasticity of suspensions of the particles, measured between 1 and 15 vol.% (0.02 and 3 wt.%) increased with concentration and was also higher at pH 4 than pH 7. However, all the suspensions were only weakly shear thinning, suggesting that they did not form very strong networks. The particles were added (at 1–15 vol.%) to a model W/W system consisting of Waxy Corn starch (S) + locust bean gum (LBG) that normally shows phase separation when the components are mixed at 90 °C then cooled to room temperature (22–25 °C). At 10 to 15 vol.% particles and pH 4, visual observation showed striking inhibition of phase separation, for a period of up to 1 year. Confocal laser scanning microscopy suggested that under these conditions extensive aggregation of the microparticles occurred within the starch phase but also possibly at the W/W interface between the starch-rich and gum-rich regions, supporting a Pickering-type mechanism as responsible for the enhanced stabilization of the W/W emulsion by the microgel particles.
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the effect of nanoparticles on the phase separation of Waxy Corn starch locust bean gum or guar gum
Food Hydrocolloids, 2014Co-Authors: Brent S Murray, Nataricha PhisarnchanananAbstract:Phase separation of mixtures of a gelatinized Waxy Corn starch (S) and locust bean gum (LBG) has been studied in detail at pH 7 and room temperature in the presence and absence of up to 1 wt.% silica nanoparticles (primary particle size 20 nm diameter). A range of silica particles of varying surface hydrophobicities was used, surface modified so as to have 100% (i.e., unmodified) to 65% of their surface SiOH groups remaining. In the absence of particles the S + LBG system separated via spinodal decomposition. In the presence of particles the phase separation was significantly curtailed. Confocal microscopy showed that the particles had a strong preference for the starch microdomains that formed, rather than the gum phase, whilst there was an increasing tendency for particle aggregation to occur within the starch microdomains and possibly at the W/W interface between the two phases as the particle hydrophobicity and particle concentration was increased. Measurements on starch + guar gum system showed that this behaved similarly to the S + LBG system. Measurements of the bulk rheology of the gum and starch phases in the presence and absence of the particles suggested that the inhibition of the phase separation was not due to changes in the viscoelasticity of the starch or gum microdomains themselves, but flocculation of the particles in the gum phase, possibly via the depletion mechanism. It is suggested that the formation of large aggregates of particles aids their accumulation at the W/W interface and subsequently slows down phase separation.
Brent S Murray - One of the best experts on this subject based on the ideXlab platform.
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whey protein microgel particles as stabilizers of Waxy Corn starch locust bean gum water in water emulsions
Food Hydrocolloids, 2016Co-Authors: Brent S Murray, Nataricha PhisarnchanananAbstract:Abstract Food-grade whey protein isolate (WPI) microgel particles were investigated as a particle stabilizer of water-in-water (W/W) emulsions. The microgel particles were produced via the novel method of forcing coarse particles of a pre-formed thermally processed WPI protein gel through a jet homogenizer. The Z-average particle size was 149 ± 89 nm but the particles showed a strong tendency for aggregation when the pH was lowered from pH 7 to 4, when the zeta potential also switched from −17 to +12 mV. The viscoelasticity of suspensions of the particles, measured between 1 and 15 vol.% (0.02 and 3 wt.%) increased with concentration and was also higher at pH 4 than pH 7. However, all the suspensions were only weakly shear thinning, suggesting that they did not form very strong networks. The particles were added (at 1–15 vol.%) to a model W/W system consisting of Waxy Corn starch (S) + locust bean gum (LBG) that normally shows phase separation when the components are mixed at 90 °C then cooled to room temperature (22–25 °C). At 10 to 15 vol.% particles and pH 4, visual observation showed striking inhibition of phase separation, for a period of up to 1 year. Confocal laser scanning microscopy suggested that under these conditions extensive aggregation of the microparticles occurred within the starch phase but also possibly at the W/W interface between the starch-rich and gum-rich regions, supporting a Pickering-type mechanism as responsible for the enhanced stabilization of the W/W emulsion by the microgel particles.
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the effect of nanoparticles on the phase separation of Waxy Corn starch locust bean gum or guar gum
Food Hydrocolloids, 2014Co-Authors: Brent S Murray, Nataricha PhisarnchanananAbstract:Phase separation of mixtures of a gelatinized Waxy Corn starch (S) and locust bean gum (LBG) has been studied in detail at pH 7 and room temperature in the presence and absence of up to 1 wt.% silica nanoparticles (primary particle size 20 nm diameter). A range of silica particles of varying surface hydrophobicities was used, surface modified so as to have 100% (i.e., unmodified) to 65% of their surface SiOH groups remaining. In the absence of particles the S + LBG system separated via spinodal decomposition. In the presence of particles the phase separation was significantly curtailed. Confocal microscopy showed that the particles had a strong preference for the starch microdomains that formed, rather than the gum phase, whilst there was an increasing tendency for particle aggregation to occur within the starch microdomains and possibly at the W/W interface between the two phases as the particle hydrophobicity and particle concentration was increased. Measurements on starch + guar gum system showed that this behaved similarly to the S + LBG system. Measurements of the bulk rheology of the gum and starch phases in the presence and absence of the particles suggested that the inhibition of the phase separation was not due to changes in the viscoelasticity of the starch or gum microdomains themselves, but flocculation of the particles in the gum phase, possibly via the depletion mechanism. It is suggested that the formation of large aggregates of particles aids their accumulation at the W/W interface and subsequently slows down phase separation.
Paul A Seib - One of the best experts on this subject based on the ideXlab platform.
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low and medium de maltodextrins from Waxy wheat starch preparation and properties
Starch-starke, 2001Co-Authors: Namfone Lumdubwong, Paul A SeibAbstract:The goal of the research was to prepare maltodextrins (MD) from Waxy wheat starch and Waxy Corn starch (control). Waxy wheat starches with 0.2% protein, 0.2% lipid and ∼1% amylose were isolated from two flours by mixing a dough, dispersing the dough in excess water, and separating the starch and gluten from the resultant dispersion. The mean recoveries were 72% for the starches and 76% for the gluten fraction with 80% protein. Maltodextrins having low-dextrose equivalence (DE) 1—2 and mid-DE 9—10 were prepared by treatment of 15% slurries of Waxy wheat starch and Waxy Corn starch at 95 °C for 5—10 min and 20—50 min, respectively, with a heat-stable α-amylase. Denaturing the enzyme and spray-drying produced MD's with bulk densities of 0.3 g/cm 3. The powdery MD's were subjected to an accelerated-rancidity development test at 60 °C, and an off-odor was detected after 2 days storage for the low-DE MD's from the two Waxy wheat starches (WxWS1-MD 1.2 and WxWS2-MD 1.5), but not for the low-DE Waxy Corn maltodextrin (WxCS-MD 2.2) or a commercial Waxy Corn MD with DE 1. None of the mid-DE 9—10 MD's developed off-odor after 30 days storage at 60 °C. The experimental products WxWS1-MD 9.2, WxWS2-MD 9.9 and WxCS-MD 9.1 showed high water-solubility and gave 1—10% aqueous solutions of high clarity with no clouding upon cooling.
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modified Waxy wheat starch compared to modified Waxy Corn starch
Journal of Cereal Science, 2000Co-Authors: I Reddy, Paul A SeibAbstract:Abstract Waxy wheat starch (WWS) and Waxy Corn starch (WCS) were cross-linked in an aqueous slurry at c. 37% starch solids with 0·013 to 0·050% phosphoryl chloride (starch basis) at pH 11·5 for 60 min in the presence of c. 2·1% sodium sulphate (starch basis). Increasing levels of phosphoryl chloride caused a steady decline in the final paste consistency of cross-linked WWS, but that of WCS proceeded through an optimum. Starch paste consistency was the resistance to stirring measured in a pasting instrument. WWS cross-linked at a low level gave a higher final paste consistency compared with cross-linked WCS. WWS and WCS were hydroxypropylated (HP) to low (c. 2·0%) and medium (c. 4·0%) levels by reaction with propylene oxide at pH 11·5 and 45 °C, and the HP starches were then cross-linked with 0·008 to 0·018% phosphoryl chloride. Again, cross-linked HP-WWS gave pasting curves with higher consistency at 6·25% starch solids compared with HP-WCS. WWS and its modified forms yielded pastes of lower clarity than those from WCS, but the pastes from HP/cross-linked WWS had better freeze-thaw stability. Cross-linking with phosphoryl chloride (0·025%) followed by acetylation with acetic anhydride (8·0%) yielded modified Waxy wheat and Waxy Corn starches with similar paste consistencies, but a force-distance instrument indicated that the modified WCS was significantly stringier than the modified WWS.
Celia Maria Landi Franco - One of the best experts on this subject based on the ideXlab platform.
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Contribuição ao estudo da estrutura do granulo de amido de milho, tratamento termico, hidrolise enzimatica e permeação em gel
2017Co-Authors: Celia Maria Landi FrancoAbstract:Resumo: No presente trabalho foi estudado o tratamento térmico sob baixa umidade e sua influência na suscetibilidade enzimática de amidos milhos normal e ceroso, visando obter maiores informações de a respeito da estrutura dos diferentes grânulos de amido. Amidos de milho normal e de milho ceroso foram extraídos e submetidos a tratamento térmico (100oC/16 horas) em diferentes teores de umidade e posteriormente submetidos à ação da α-amilase e amiloglucosidase. Índice de absorção de água e propriedades de pasta destes amidos foram determinadas e os residuos da hidrólise foram analisados cristalográfica, microscópica e cromatograficamente. Os resultados obtidos com os amidos de milho normal e ce¬roso tratados a 18% de umidade mostraram que o tratamento térmico provocou aumento da cristalinidade sugerindo rearranjo das moléculas de amido com fortalecimento das ligações internas dos grânulos e maior grau de associação das cadeias de amido. Este fato ocasional queda drástica na suscetibilidade enzimática destes amidos. Por outro lado, para os amidos tratados a 27% de umidade, o tratamento térmico pareceu ter provocado rompimento seguido de rearranjo das ligações internas dos grânulos induzindo a alguma degradação do amido e aumentando marcadamente a área acessível à amilólise. O tratamento térmico não provocou mudanças no tamanho ou forma dos grânulos de amido, mas tanto o tratamento térmico como o enzimático resultaram em alterações nas zonas amorfas dos grânulos de amido. Através de microscópia eletrônica de varredura, observou- se que os grânulos de amido natural possuem estrutura porosa e o ataque enzimático provocou extensa corrosão através de canais radiais. A hidrólise enzimática sobre ambos amidos, normal e ceroso, tratados termicamente a 27% de umidade, além da corrosão através de canais radiais, provocou maior quebra dos grânulos como se a estrutura restante se rompesse com maior facilidade. A conhecida estrutura disposta em camadas concêntricas alternadamente claras e escuras foi observada para ambos amidos tratados enzimaticamente. Cromatografia em gel Sephadex G-50 das α-glucanas dos amidos de milho normal e ceroso submetidos ou não ao tratamento térmico a 27% de umidade foi realizada diretamente e após sucessivas digestões enzimáticas com pululanase e β -amilase. Os resultados mostraram que existem diferenças nos residuos dos amidos de milho ceroso e normal tratados com α- amilase e amiloglucosidase. No resíduo do amido de milho ceroso os perfis de eluição mostraram duas frações a 290 e 350ml "(picos II e III) respectivamente, muito pequenas que não eram suscetíveis ao ataque da α- amilase e amiloglucosidase indicando que estas frações faziam parte das zonas cristalinas do amido. Estas frações também faziam parte das áreas cristalinas no amido normal. No entanto, a presença do pico V a 390ml na α-glucanas do amido de milho normal sugeriu que além das duas frações não suscetíveis à hidrólise, existia outra que também participava das zonas cristalinas deste amido. A presença deste pico a 390ml sugeriu o arranjo cristalino distinto entre o amido de milho ceroso e normal. Por outro lado, o tratamento térmico a 27% de umidade não foi capaz de romper totalmente suas ligações e esta fração continuou presente após tratamento térmico e enzimático como regiões não suscetíveis à hidrolise formando, conseqüentemente, rede cristalina fortemente associada.Abstract:In order to obtain more information on the structure of Corn starch, it was studied the heat-moisture treatment of normal and Waxy Corn starches and its influence on the enzymatic susceptibility of these starches. Normal and Waxy Corn starches were isolated and adjusted to different levels of moisture and heated at 100°C for 16 h. Afterwards, all starches were hydrolysed with α-amylase and amyloglucosidase. Water-binding capacities and pasting properties were determined and the starch granule residues of the hydrolysis were studied by X-ray diffraction, optical and scanning electron microscopy and gel-permeation chromatography. The results showed that the heat-moisture treatment produced an increase in the degree of cristallinity of normal and Waxy Corn starches adjusted to 18% moisture before being heated, indicating a rearrangement of the starch molecules with strengthening of the linkages within granules of starch and consequently, an increase in the degree of association of the starch chains. This fact resulted in significant decrease in the enzymatic susceptibility of the starches. On the other hand, the heat-moisture treatment provided a rupture, with further rearrangement, of the linkages within granules of starches and even a certain degree of starch degradation occurred, when starches were adjusted to 27% moisture before being heated. This fact increased significantly the accessible regions of the granule to amylolysis. The heat-moisture treatment did not alter the appearance of the starch granules. No obvious changes in size and shape nor any fissures or distortions were found. The heat-moisture treatment as well as the enzymatic one occurred in the amorphous regions of the starch granules. Observations of the granules with scanning electron microscope showed that natural starch granules have a porous surface and the enzymatic attack provided an extensive corrosion of granule surface by formation of radial channels. In addition,the enzymatic hydrolysis on the normal and Waxy Corn starches adjusted to 27% moisture before heating, produced major break of the granules as if parts of the structure ruptured more easily. The known structure formed by several concentric layers alternatively light and dark was observed for all starches treated with enzymes. Sephadex G-50 gel-permeation chromatography of the α-glucan of normal and Waxy Corn starches submitted or not to heat treatment with 27% moisture was performed directly and after successive enzymatic digests with pullulanase and β-amylase. The results showed differences in the residues of the Waxy and normal Corn starches treated with α-amylase and amyloglucosidase. The elution patterns of the Waxy Corn starch residue showed two small fractions at 290 and 350 ml (peak II and III) respectively, which were not susceptible to the α-amylase and amyloglucosidase' attack indicating that these fractions took part in the Waxy starch cristalline areas. These fractions also took part in normal starch cristalline area. However, in addition to two chains not susceptible to hydrolysis, the presence of the peak V at 390 ml on the α-glucan of the normal Corn starch suggested the existence of another fraction that also took part in normal Corn starch cristalline areas. The presence of this peak at 390 ml suggested the distinct cristalline arrangement between the Waxy and normal Corn starches. On the other hand, the heat-moisture treatment at 27% moisture was not capable of rupturing all linkages and this fraction was still present after thermic and enzymatic treatment as regions not susceptible to hydrolysis, consequently forming tightly associated cristalline network
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the structure of Waxy Corn starch effect of granule size
Starch-starke, 1998Co-Authors: Celia Maria Landi Franco, Cf Ciacco, Debora De Queiroz TavaresAbstract:The granules of Waxy Corn starch were isolated and various samples were separated by size and classified according to their average diameter in: non-separated granules (N), granules with diamcter < 15 μm (S) and granules with diameter ≥ 15 μm (L). The samples were hydrolyzed by bacterial α-amylase and fungal amyloglucosidase. The starch granules remaining after enzymatic hydrolysis were analysed by X-ray diffraction and optical and scanning electron microscopy. Sephadex G-50 gel permeation chromatography of the dissolved residues from the hydrolysis of the N and S samples was performed directly and after successive enzymatic digestion with pullulanase and β-amylase. The results showed that the percentage of hydrolysis increased with a decrease in diameter. No apparent differences in Waxy Corn starch when observed under light and scanning electronic microscope were observed, regardless of diameter and enzyme action, although both large and small granules showed extensive surface corrosion after enzymatic attack. X-ray analysis suggested a decrease in the quantity of crystalline areas in the smaller granules, which would explain the high percentage of hydrolysis evidenced by these granules. The elution patterns of the α-glucans of both starches (N and S) were similar and reveled the presence of two fractions which were not susceptible to α-amylase and amyloglucosidase attack suggesting that these fractions were involved in the Waxy Corn starch crystalline regions. Debranching with pullulanase followed by gel-permeation chromatography showed that the amylopectins from the starch granules studied contained three groups of unit chains instead of the two reported in the literature.
Dominique Dufour - One of the best experts on this subject based on the ideXlab platform.
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Thermomechanical characterization of an amylose-free starch extracted from cassava (Manihot esculenta, Crantz)
Carbohydrate Polymers, 2017Co-Authors: Adriana Pulido Diaz, Denis Lourdin, Guy Della Valle, Alejandro Fernandez Quintero, Hernan Ceballos, Thierry Tran, Dominique DufourAbstract:The aim of this study was to determine and compare the melting (T-m), glass transition (T-g) and mechanical relaxation (T-alpha) temperatures of a new Waxy cassava starch. Thermal transitions measurements were obtained by Differential Scanning Calorimetry (DSC) and Dynamical Mechanical Thermal Analysis (DMTA). The experimental data showed a high correlation between water volume fraction and melting temperature (T-m) indicating that the Flory-Huggins theory can be used to describe the thermal behavior of this starch. The T-m of Waxy cassava starch-water mixes were lower than a Waxy Corn starch-water reference system, but differences were not statistically significant. The mechanical relaxation temperatures taken at tan delta peaks were found 29-38 degrees C larger than T-g. The T-alpha and T-g measured for Waxy cassava starch exhibited similar properties to the ones of Waxy Corn starch, implying that Waxy cassava starch can be used in food and materials industry.
