Starch Slurry Research Articles

Comparative optimization study for chemical synthesis of hydroxypropyl starch from native corn and taro starch through evolutionary operation (EVOP) factorial design technique

Modification of native starch is aimed at tailor‐making functional properties of starch to overcome its inherent shortcomings which will enhance its versatility for different food‐uses. Optimization of chemical synthesis of hydroxypropyl starch from two native starch sources, corn and taro, was explored through application of evolutionary operation (EVOP) factorial design technique. Concentrations of starch slurry, propylene oxide, and sodium sulfate were considered as process variables and these were optimized in order to maximize swelling power of hydroxypropyl starch. EVOP factorial designing technique was applied consecutively and the results were analyzed statistically. Maximization of swelling power was achieved by corn starch after two sets of experiments of EVOP and the maximum value obtained was 36.17 at 20% sodium sulfate, 50% starch slurry, and 3.2% propylene oxide concentrations. The highest value of swelling power for hydroxypropyl taro starch was measured to be 62.33 after two sets of experiments and there was still scope for increasing its value in further set of experiments. Final conditions for taro starch were found to be optimum at 30% sodium sulfate, 40% starch slurry, and 5.6% propylene oxide concentrations, evaluated through EVOP method.

Physico-chemical properties of acetylated starches from Indian black gram (Phaseolus mungo L.) cultivars.

Starches separated from three black gram cultivars were modified by acetylation and compared to their native starches. Acetylation was carried out by treating starches with 0.04 and 0.08g of acetic anhydride/g of starch dry weight basis (db) at 25°C. The extent of acetylation increased proportionally with the concentration of acetic anhydride used. Retrogradation of acetylated starch pastes decreased significantly (p ≤ 0.05) as revealed by significant decrease in syneresis, increased freeze thaw stability and increased light transmittance. The pasting curves of 10.7% starch slurries showed that acetylation decreased the setback viscosity values by 51.2-82.8% and pasting temperature by 3.1-5.6°C than respective native starches. Differential scanning calorimetry observations also revealed significant decrease in gelatinisation temperature of acetylated starches than native starches. Hardness and adhesiveness of starch gels varied between 10.3 and 32.6g and 4.6-82.3gs, respectively which were significantly lower than corresponding native starch gels.

Saccharification and liquefaction of cassava starch: an alternative source for the production of bioethanol using amylolytic enzymes by double fermentation process.

BackgroundCassava starch is considered as a potential source for the commercial production of bioethanol because of its availability and low market price. It can be used as a basic source to support large-scale biological production of bioethanol using microbial amylases. With the progression and advancement in enzymology, starch liquefying and saccharifying enzymes are preferred for the conversion of complex starch polymer into various valuable metabolites. These hydrolytic enzymes can selectively cleave the internal linkages of starch molecule to produce free glucose which can be utilized to produce bioethanol by microbial fermentation.ResultsIn the present study, several filamentous fungi were screened for production of amylases and among them Aspergillus fumigatus KIBGE-IB33 was selected based on maximum enzyme yield. Maximum α-amylase, amyloglucosidase and glucose formation was achieved after 03 days of fermentation using cassava starch. After salt precipitation, fold purification of α-amylase and amyloglucosidase increased up to 4.1 and 4.2 times with specific activity of 9.2 kUmg-1 and 393 kUmg-1, respectively. Concentrated amylolytic enzyme mixture was incorporated in cassava starch slurry to give maximum glucose formation (40.0 gL-1), which was further fermented using Saccharomyces cerevisiae into bioethanol with 84.0% yield. The distillate originated after recovery of bioethanol gave 53.0% yield.ConclusionAn improved and effective dual enzymatic starch degradation method is designed for the production of bioethanol using cassava starch. The technique developed is more profitable due to its fast liquefaction and saccharification approach that was employed for the formation of glucose and ultimately resulted in higher yields of alcohol production.

Green preparation and characterisation of waxy maize starch nanoparticles through enzymolysis and recrystallisation

Waxy maize starch was treated by a facile and green enzymolysis procedure to fabricate starch nanoparticles (StNPs). The yield of StNPs was raised to 85% by pullulanase treatment, and the preparation duration was two days. Morphology (SEM, TEM), crystalline structure (XRD), thermal gravimetry analysis (TGA), and the group changing (FTIR) of StNPs prepared with different starch concentrations (10%, 15%, 20% and 25%,w/v) were investigated. Compared with native starch, the topography of all StNPs exhibited irregularly-shaped fragments, the particle diameters decreased from several μm to about 60–120nm, and the crystal pattern changed from A-type to B+V-type. The StNPs prepared with 15% starch slurry had the highest degree of crystallinity at 55.41%. The eco-friendly prepared nanoparticles could be widely used in biomedical applications and development of new materials.

Ultrasonic machining of biomass using biodegradable slurry

Thrombi, e.g. blood clots, in circulatory system pose acute health risk, globally. This research investigated roles of biodegradable starch slurry in advancing biomass machining efficiency. Hard clots (fibrin-rich) prepared from rabbit blood were exposed in vitro concomitantly to ultrasound (1MHz) and starch slurry. Starch slurry particles (diameter ∼250nm) yielded a 200% increase in material removal (sonothrombolysis) efficiency. Mechanistic participation of starch, a non-Newtonian material, at the interface of biomass-ultrasonic radiation is discussed. Overall in subtractive biomanufacturing, the role of biodegradable slurry is critical for enhancing material removal efficiency.

Modification of tapioca starch by non-chemical route using jet atmospheric argon plasma

Non-chemical modification of tapioca starch was investigated using jet atmospheric argon plasma treatment. Two forms of starch slurry, i.e. granular starch (G) and cooked starch (C), were jet-treated by argon plasma generated by supplying input power of 50W (denoted as G50 and C50 samples) and 100W (denoted as G100 and C100 samples) for 5min. Physical, rheological, and structural characteristics of the modified starch were investigated. The G50 and C100 samples had lower paste clarity but higher thermal stability and performed stronger gels (G50 only) compared to their control counterparts. On the other hand, the analyzed properties of the G100 and C50 samples showed the opposite trend. FTIR and 1H NMR results revealed that the relative areas of COC and OH peaks were changed after the treatment. Cross-linking reaction seemed to predominantly take place for the G50 and C100 samples, whereas depolymerization predominated for the G100 and C50 samples.

Intensification of Starch Processing Using Apparatus with Couette–Taylor Flow

AbstractCouette–Taylor flow (CTF), which is characterized by the presence of Taylor vortices, ensures effective mixing, fast heat transfer and improved rheological properties of starch slurry. Therefore, this type of flow can be expected to provide favorable conditions for starch processing. In order to check how to intensify the process, starch gelatinization has been studied experimentally and using computer simulation in two CTF apparatuses of different volumes. The results show that, when the volume of apparatus was small, high value of degree of starch gelatinization could be achieved at relatively low temperature or at relatively low rotor rotation frequency. The increase in the apparatus volume ensures higher rate of gelatinized starch production and the reduction in dissipation of mechanical energy connected with rotor rotation, however, it also amplifies the detrimental inlet and gravitation effects. To overcome both of these negative effects, the increase in the rotor frequency is required.Practical ApplicationStarch gelatinization is a process frequently encountered in food industry, e.g., food sterilization or starch hydrolysis. Therefore, a new way of starch processing could be interesting in the context of growing consumer interest in natural food. It is expected that CTF apparatus could enable to process much more concentrated starch slurry than a jet cooker or coil heater typically used in industrial setting. Starch granules should also be less damaged during treatment in CTF apparatus than in an extruder. The results presented in this paper are relevant for process intensification and scale‐up of starch gelatinization in CTF apparatus and will be extended to simultaneous starch gelatinization with enzymatic hydrolysis in the future work.

Starch consolidation of red clay-based ceramic slurry inside a pressure-cooking system

The consolidation of red clay-based slurry by gelatinization of starch in a domestic pressure cooker was presented. Aqueous ceramic slurries were prepared consisting of a ternary powder mixture of red clay, quartz, feldspar, and different starch types. The starch slurries with and without the presence of ceramic particles demonstrated the same gelling mechanism and heating time inside the pressure cooker. The gel strengths of pressure-cooked samples were higher than samples heated conventionally. Subsequently, the shaping of large ceramic prototypes is possible using a calculated heating time based on best pressure cooking conditions. The physical characterizations disclosed that the pressure-cooked ceramic samples in dried and fired states exhibited better physical properties depending upon the type of starch added in the ceramic slurry. Specifically, the compressive strengths of fired ceramic bodies shaped in the pressure cooker ranged from 82 ± 2 to 255 ± 9 MPa with bulk porosities of 29.0 ± 0.8-18.7 ± 0.2%, whereas the conventionally shaped bodies possessed compressive strengths ranging from 138 ± 8 to 164 ± 11 MPa with bulk porosities of 25.6 ± 0.1-28.5 ± 0.2%.

Sago starch as binder and pore-forming agent for the fabrication of porcelain foam

The aim of this study is to verify the potential of sago starch (Metroxylon sagu) as a binder and pore-forming agent for the fabrication of porcelain foam. The porcelain foam was fabricated via the polymeric foam replication technique. Initially, the porcelain raw material was mixed in water with several binders (respectively) to form a slurry. Replication starts by fully submerging a compressed sponge in the slurry. Excess slurry was then removed by hand squeezed and pressed between two parallel plates. Subsequently, the impregnated sponge was sintered at 500°C and up to 1250°C for 2h for sponge and binder removal and porcelain to mature, respectively. The results from this work showed that sago starch slurry produced porcelain with density, total porosity and compressive strength of 0.37–0.51gcm−3, 79–81%, and 0.33–0.93MPa, respectively. The increased of porosity and compressive strength are perhaps due to the addition of sago starch which changed the rheological property of the slurry from Newtonian to pseudoplastic behavior. This results in higher value of viscosity, consequently allowing the construction of smoother and uniform cell skeleton although with existence of micro-pores on the structure, which contributed to higher compressive strength. The results from this study showed that sago starch has huge potential as a binder and a pore-forming agent, whilst providing a simpler and cheaper route for the fabrication of cellular ceramics.

RS4 형태의 옥수수 저항전분이 첨가된 쿠키의 품질 특성

Effects of RS4 type resistant corn starch on the quality characteristics of cookies were investigated by physicochemical, instrumental and sensory evaluation. The resistant starch was made by cross-linking of corn starch as following; corn starch slurry was annealed at pH 2.0 and for 2 h followed by the cross-linking reaction. The cross-linking reaction was performed at for 12 h in the presence of 1.2%/st.ds NaOH, 10%/st.ds sodium sulfate and 10%/st.ds of sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) mixture. Dietary fiber content of the resistant starch was estimated to be 73.8% by the AOAC method. For quality characteristics, dough pH decreased with the increase of the resistant starch content and spread factor decreased a little at 20% of the resistant starch. The moisture content and L value of cookies increased with the increase of the resistant starch content. However, the hardness and fracturability decreased with the increase of the resistant starch content. In the sensory evaluation, no significant differences were observed between the two cookies with or without the resistant starch. The results of this study suggest that the RS4 type resistant corn starch can be a good ingredient to increase dietary fiber content in cookies without changes of their qualities.

Effect of thermostable α -amylase injection on mechanical and physiochemical properties for saccharification of extruded corn starch

In industry, a jet cooker is used to gelatinize starch by mixing the starch slurry with steam under pressure at 100-175 °C. A higher degree of starch hydrolysis in an extruder is possible with glucoamylase. Unfortunately, it is difficult to carry out liquefaction and saccharification in parallel, because the temperature of gelatinization will be too high and will inactivate glucoamylase. Since the temperature for liquefaction and saccharification is different, it is hard to change the temperature from high (required for liquefaction) to low (required for saccharification). The industrial gelatinization process is usually carried out with 30-35% (w/w) dry solids starch slurry. Conventional jet cookers cannot be used any more at high substrate concentrations owing to higher viscosity. In this study, therefore, corn starch was extruded at different melt temperatures to overcome these limitations and to produce the highest enzyme-accessible starch extrudates. Significant effects on physical properties (water solubility index, water absorption index and color) and chemical properties (reducing sugar and % increase in reducing sugar after saccharification) were achieved by addition of thermostable α-amylase at melt temperatures of 115 and 135 °C. However, there was no significant effect on % increase in reducing sugar of extruded corn starch at 95 °C. The results show the great potential of extrusion with thermostable α-amylase injection at 115 and 135 °C as an effective pretreatment for breaking down starch granules, because of the significant increase (P < 0.05) in % reducing sugar and enzyme-accessible extrudates for saccharification yield.

Effect of lauric acid on the V-amylose complex distribution and properties of swelled normal cornstarch granules

Starch–fatty acid complexes were prepared using swelled normal cornstarch (NC) and lauric acid (LA). Two different modes of adding LA to the starch slurry were employed; i.e. either adding the LA to the heated starch suspension (method I) or adding the LA to the starch suspension and then heating (method II). Effects of the modes of adding LA on the V-amylose complex distribution and digestibility were studied. Lipid content determination indicated that method I is favorable to the formation of V-amylose complex. Light and confocal laser scanning microscopic examination indicated that NC–LA complex prepared by method I seemed to be more swollen, and the V-amylose complex distributed throughout the granules, while NC–LA complex prepared by method II was mainly distributed on the surface of starch granules. The results of X-ray diffraction and thermal property demonstrated that method I was more beneficial to the formation of more crystalline structure than that of method II. The in vitro digestibility investigation showed that the addition of LA through method I had the ability of slowing the hydrolysis of starch.

Improving rate performance of LiFePO4 cathode materials by hybrid coating of nano-Li3PO4 and carbon

Li3PO4 coating on the surface of LiFePO4 particles was prepared by direct dispersing LiFePO4 precursor in starch slurry with nano-Li3PO4. The existence of nano-Li3PO4 was confirmed with X-ray powder diffraction (XRD). And the particle size and morphology were observed by scanning electron microscope (SEM) and transmission electron microscope analysis (TEM). The effects of the mixture coating on rate performance of LiFePO4 cathode vs Li anode at 25°C was investigated. Li3PO4 and carbon mixing coated LiFePO4 cathode materials exhibited markedly improved rate capability relative to bare carbon-coated LiFePO4. Analyses on cell impedance showed that the Li3PO4 coating decreased the interfacial impedance. Transmission electron microscope analysis, electrochemical impedance spectroscopy (EIS) and cyclic voltammograms (CV) were carried out to explain the reason of better rate performance by Li3PO4 coating.

Shear thickening of corn starch suspensions: Does concentration matter?

Suspensions of corn starch and water are the most common example of a shear thickening system. Investigations into the non-Newtonian flow behavior of corn starch slurries have ranged from simplistic elementary school demonstrations to in-depth rheological examinations that use corn starch to further elucidate the mechanisms that drive shear thickening. Here, we determine how much corn starch is required for the average person to “walk on water” (or in this case, run across a pool filled with corn starch and water). Steady shear rate rheological measurements were employed to monitor the thickening of corn starch slurries at concentrations ranging from 0 to 55wt.% (0–44vol.%). The steady state shear rate ramp experiments revealed a transition from continuous to discontinuous thickening behavior that exists at 52.5wt.%. The rheological data was then compared to macro-scopic (∼5gallon) pool experiments, in which thickening behavior was tested by dropping a 2.1kg rock onto the suspension surface. Impact-induced thickening in the “rock drop” study was not observed until the corn starch concentration reached at least 50wt.%. At 52.5wt.%, the corn starch slurry displayed true solid-like behavior and the falling rock “bounced” as it impacted the surface. The corn starch pool studies were fortified by steady state stress ramps which were extrapolated out to a critical stress value of 67,000Pa (i.e., the force generated by an 80kg adult while running). Only the suspensions containing at least 52.5wt.% (42vol.%) thickened to high enough viscosities (50–250Pas) that could reasonably be believed to support the impact of a man’s foot while running. Therefore, we conclude that at least 52.5wt.% corn starch is required to induce strong enough thickening behavior to safely allow the average person to “walk on water”.

Contamination issues in a continuous ethanol production corn wet milling facility

Low ethanol yields and poor yeast viability were investigated at a continuous ethanol production corn wet milling facility. Using starch slurries and recycle streams from a commercial ethanol facility, laboratory hydrolysates were prepared by reproducing starch liquefaction and saccharification steps in the laboratory. Fermentations with hydrolysates prepared in the laboratory were compared with plant hydrolysates for final ethanol concentrations and total yeast counts. Fermentation controls were prepared using hydrolysates (plant and laboratory) that were not inoculated with yeast. Hydrolysates prepared in the laboratory resulted in higher final ethanol concentrations (15.8 % v/v) than plant hydrolysate (13.4 % v/v). Uninoculated controls resulted in ethanol production from both laboratory (12.2 % v/v) and plant hydrolysates (13.7 % v/v), indicating the presence of a contaminating microorganism. Yeast colony counts on cycloheximide and virginiamycin plates confirmed the presence of a contaminant. DNA sequencing and fingerprinting studies also indicated a number of dissimilar communities in samples obtained from fermentors, coolers, saccharification tanks, and thin stillage.

Porous rice powder from the precipitation of gelatinized flour or starch paste with ethanol

AbstractHot paste obtained by autoclaving (130°C, 25 psi, 20–30 min) a 5–7% w/w rice flour or starch slurry was precipitated with ethanol (three extractions) to produce a dry, porous, pregelatinized powder with an average particle size of 75.0 µm (flour‐derived powder) and 41.6 µm (starch‐derived powder). The microstructure of the individual particles was characterized by an interconnecting lattice of irregularly shaped vesicles, and with cavities of varying size and shape. The vesicular network was relatively thinner and finer for the starch‐derived products compared with the flour‐derived ones. In comparison with native flour and starch, the bulk density of pregelatinized powders decreased; solvent uptake (water, oil, and alcohol), swelling power, and in vitro starch digestibility increased; whereas, gel consistency, freeze–thaw stability, and AAM content sparingly changed. Changes in morphological and physicochemical properties were generally more evident on the starch‐derived products compared with the flour‐derived counterparts. To some extent, changes in properties were also affected by severity of the gelatinization treatment (varying slurry concentration and autoclaving duration). The pregelatinized rice products as developed may be useful in food and non‐food applications.

Evaluation of Complexed Starch-Urea-Citrate as A Novel Super Disintegrant

The present investigation deals with the synthesis of starch-urea-citrate complex polymer by gelatinizing starch slurry with urea and citric acid. The formed starch-urea-citrate (SUC) polymer was found to be colorless and free flowing powder. Fast disintegrating tablets of ofloxacin were prepared using different concentrations of starch-urea-citrate (7.5-30% w/w of tablet) and evaluated for both pre and post compression studies. The results of granular micromeritic properties like bulk density, angle of repose, Carr’s index and hausner’s ratio showed that all the formulations possessed good flow properties, uniformity and compressibility. The complexation of SUC synthesis and also the compatibility between ofloxacin and the polymer were confirmed by IR spectroscopy. The compressed tablets showed good hardness (3.5-4kg/cm2) and friability values < 0.5% with uniformity in drug content within the range of 99.2 to 100.2 %. The disintegration time of all the formulations was less than one minute. From the results, it was observed that with increments in starch-urea-citrate concentration in the formulations, there was a decrease in the values of wetting time and the disintegration time. The optimized formulation showed a complete in-vitro drug release within 40 min. as compared to the commercial product. Thus it was made evident that the starch-urea-citrate could be used as an excellent super disintegrant.

Recovery of sporamin from naturally fermented sweet potato starch slurry by foam fractionation

SummaryTo recover sporamin, the major storage protein in sweet potato (Ipomoea batatas L. Lam.), from the wastewater generated by starch extracting industry by foam fractionation, the pH of the wastewater must be decreased to near three. This work explores a novel strategy where natural fermentation of the starch slurry was used to lower the pH without adding any acids. This work shows that after fermenting for 7 days the pH in the slurry significantly decreased from 6.57 ± 0.15 to 3.40 ± 0.00 (P &lt; 0.05). Subsequently, sporamin was successfully recovered from the slurry with a peak recovery and enrichment of 87.9 ± 6.07% and 1.55 ± 0.11, respectively, at day 7. However, the concentration of protein in the slurry decreased correlatively with the decrease in pH value (r = 0.828, P = 0.042). Taken together, we concluded that the new strategy is feasible for recovering sporamin from the wastewater and fermentation for 4−7 days was recommended.

Functional characterization of native starches through thermal and rheological analysis

Native starch samples (corn, rice, and tapioca starches) were prepared in an aqueous slurry and dough system, and their functional properties were evaluated in terms of thermal and rheological characteristics. The pasting property results of starch slurries showed that rice starch exhibited the lowest peak temperature, whereas the highest peak viscosity was observed in tapioca starch. When starch suspensions were subjected to dynamic oscillatory temperature sweep testing, the increased storage moduli and reduced tan δ derived from starch gelatinization were clearly observed in all starch samples, showing that the gelatinized starch granules became more elastic. Steady shear measurements revealed the shear-thinning behaviors of starch pastes, which were dominant in tapioca starch, compared to the other starches. In addition, the distinct endothermic peaks of starch gelatinization were observed at 73.15, 62.25, and 70.55°C for corn, rice, and tapioca starches, respectively and these trends were in good agreement with the pasting and viscoelastic results. However, upon incorporation of the native starches to a wheat dough system, the highest dough consistency during heating and cooling was observed in corn starch probably due to the rigidity of its particle. Thus, the physicochemical response of native starches to temperature appeared to be different in different concentration regimes.

옥수수 전분유의 Annealing 조건이 인산가교 저항 전분의 형성에 미치는 영향

옥수수 전분의 인산화 가교반응에 의한 RS4 제조 시 최적 annealing 조건을 검토하였다. 전분유에 NaOH를 0.9%, 1.2%, 1.5%/st.ds의 농도가 되게 첨가하고 복합인산염(STMP/STPP 혼합)을 이용하여 인산화 가교반응 할 경우 NaOH 농도가 높을수록 반응 초기에 RS 함량이 빠르게 증가되었으나 NaOH 농도에 상관없이 반응 12시간 후에는 비슷한 RS 함량을 나타내었다. 전분유의 Annealing 처리는 인산화 가교반응 전에 실시하였다. 전분유를 pH 2-10, 온도 <TEX>$40-60^{\circ}C$</TEX>, 0-14시간으로 처리한 후 인산화 가교반응을 하였다. Annealing 처리시 pH가 낮을수록 RS 함량이 높아지는 결과를 보였으며 pH 2에서 annealing 온도 <TEX>$50^{\circ}C$</TEX>, 2시간 annealing에서 최고의 RS 함량을 나타내었다. 따라서 최적 인산화 가교반응 조건은 먼저 pH 2.0, <TEX>$50^{\circ}C$</TEX>에서 2시간 annealing 처리를 한 후 황산나트륨 농도 10%/st.ds, NaOH 농도 1.2%/st.ds 조건에서 12시간 인산화 가교반응을 행하는 것으로 생각된다. RS 함량은 인산염 투입량이 증가함에 따라 직선적으로 증가하였다. 본 연구결과에 의한 최적조건을 활용하여 복합인산염 10%/st.ds의 농도로 RS4를 제조한 결과 RS 함량은 72.3% 였으며 인의 함량은 0.36%/st.ds로 한국 식품첨가물 공전에 적합하여 식품용 소재로 활용이 가능할 것으로 사료된다. The optimum annealing conditions of corn starch slurry were studied for RS4 type resistant starch production by phosphorylated cross-linking. When a corn starch slurry was cross-linked by using phosphate salts (STMP/STPP mixture) in the presence of 0.9%, 1.2% and 1.5% NaOH/st.ds, a high concentration of NaOH resulted in a rapid increase of the RS contents at the early reaction stage. However, similar RS contents were obtained after 12 h of cross-linking regardless of NaOH concentrations. The annealing treatment was conducted under various conditions such as pH between 2-10, temperature <TEX>$40-60^{\circ}C$</TEX>, time 0-14 h followed by phosphorylated cross-linking. The lower slurry pH was for the annealing treatment, the higher RS contents were obtained after cross-linking. When the slurry annealed for various period of time and temperature, a maximal amount of RS was formed after 2 h of annealing at <TEX>$50^{\circ}C$</TEX> of annealing temperature of the starch slurry (pH 2.0). Therefore, an optimal annealing conditions at pH 2.0 and <TEX>$50^{\circ}C$</TEX> for 2 h were proposed under the cross-linking conditions of sodium sulfate 10%/st.ds, NaOH 1.2%/st.ds and 12 h of the reaction time. The RS contents were linearly increased with the increase of phosphate salt addition. The RS4 prepared under the optimal conditions contained RS 72.3% and its phosphorus content was 0.36%/st.ds, which was below the limit (0.4%/st.ds) of modified starch by Korea Food Additives Code.