PREPARING A BLEND OF POLYSACCHARIDE AND INGREDIENT

Abstract

The invention is directed to a method of preparing a blend comprising a polysaccharide and a water soluble or dispersible ingredient. More in particular, the invention relates to the preparation of such blend using a filter centrifuge. The method of the invention comprises a. feeding a polysaccharide slurry to a filter centrifuge via a first inlet; b. rotating the filter centrifuge at a first centrifuge speed to provide a polysaccharide cake; c. feeding a sprayable ingredient to the filter centrifuge via a second inlet; and d. spraying the sprayable ingredient onto the polysaccharide cake while rotating the filter centrifuge at a second centrifuge speed to produce a blend of the polysaccharide and the ingredient.

Claims

1. A method of preparing a blend comprising a polysaccharide and an ingredient, the method comprising: a) feeding a polysaccharide slurry to a filter centrifuge via a first inlet; b) rotating the filter centrifuge at a first centrifuge speed to provide a polysaccharide cake; c) feeding a sprayable ingredient to the filter centrifuge via a second inlet; and d) spraying the sprayable ingredient onto the polysaccharide cake while rotating the filter centrifuge at a second centrifuge speed to produce a blend of the polysaccharide and the ingredient.

2. The method according to claim 1, wherein the polysaccharide is one or more selected from the group consisting of hydrocolloids, cellulose, cellulose derivatives, starch, starch derivatives, maltodextrin, dextrin manno-oligosaccharides, xylo-oligosaccharides, polydextrose, glycogen, citrus fibres, cocoa fibres, and glucans.

3. The method according to claim 1, wherein the ingredient is one or more selected from the group consisting of salts, such as sodium carbonate, potassium carbonate, ammonium carbonate, calcium carbonate, sodium persulphate, potassium persulphate, ammonium persulphate, sodium sulphate, potassium sulphate, ammonium sulphate, sodium citrate, potassium citrate, ammonium citrate, lime; and additives, such as biocides, pH buffers; pH adjusting chemicals, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, hydrogen chloride, sulphuric acid; processing aids, antifoaming agents, flowing agents, and bleaching agents.

4. The method according to claim 1, wherein the polysaccharide slurry that is fed to the filter centrifuge has a slurry-solvent content of 40-90% by total weight of the slurry, such as 50-80%, or 55-75%, wherein said slurry-solvent preferably comprises water.

5. The method according to claim 1, wherein the first centrifuge speed is 300-1500 rpm, preferably 400-1200 rpm, such as 500-1000 rpm; and/or wherein the second centrifuge speed is 50-1000 rpm, 200-500 rpm, or 250-400 rpm.

6. The method according to claim 1, wherein sprayable ingredient is a sprayable mixture of the ingredient in an ingredient-solvent, wherein said ingredient-solvent preferably comprises water.

7. The method according to claim 6, wherein the concentration of the ingredient in the sprayable mixture is 0.1-400 g/l, such as 0.5-250 g/l, 1-100 g/l, 2-75 g/l, 5-50 g/l, or 10-40 g/l.

8. The method according to claim 1, wherein the sprayable ingredient is sprayed over the polysaccharide cake using a spray bar.

9. The method according to claim 1, wherein the polysaccharide cake at the start of spraying the sprayable ingredient has a solvent content of 20-60% by total weight of the polysaccharide cake, such as 25-50%, or 30-45%.

10. The method according to claim 1, wherein the amount of sprayable ingredient sprayed is 0.1-0.61 per kg of polysaccharide cake, such as 0.1-0.5 l, or 0.15-0.4 l.

11. The method according to claim 1, wherein the sprayable ingredient is sprayed at a rate of 10-1000 ml/min/kg polysaccharide, such as 100-500 ml/min/kg polysaccharide.

12. The method according to claim 1, wherein the sprayable ingredient is sprayed for over a period of 1-60 min, such as 2-50 min, 3-35 min, or 4-20 min, or 5-15 min.

13. The method according to claim 1, wherein the polysaccharide cake has a thickness of 0.5-10 cm, such as 1-7 cm, or 2-5 cm.

14. The method according to claim 1, further comprising removing solvent from the polysaccharide cake before spraying the sprayable ingredient.

15. The method according to claim 1, further comprising drying the blend, such as by centrifuging and/or blowing of hot air.

Description

EXAMPLES

Comparative Example 1—Addition of Salt in Last Fraction of Slurry

[0096] A starch slurry (38% dry solids) was prepared by mixing 11.5 kg of starch with 15.5 kg of water. Sodium chloride salt was mixed into the slurry in a conventional mixer in an amount of 10% based on total slurry weight (2 kg). The slurry was fed to a filter centrifuge, which was rotated at a centrifuge speed of 700 rpm, at a rate of 350 l/h. After all slurry was fed to the centrifuge, the centrifuge speed was increased to 1400 rpm and the filter cake was centrifuged for 10 min. The resulting blend had a moisture content of 35-42% based on total weight.

Comparative Example 2—Addition of Salt in Last Fraction of Slurry

[0097] A starch slurry (38% dry solids) was prepared by mixing 11.5 kg of starch with 15.5 kg of water. Sodium chloride salt was mixed into the slurry in a conventional mixer in an amount of 10% based on total slurry weight (1 kg). The slurry was fed to a filter centrifuge, which was rotated at a centrifuge speed of 700 rpm, at a rate of 350 l/h. After all slurry was fed to the centrifuge, the centrifuge speed was increased to 1400 rpm and the filter cake was centrifuged for 10 min. The resulting blend had a moisture content of 35-42% based on total weight.

Comparative Example 3—Addition of Salt in Last Fraction of Slurry

[0098] A starch slurry (38% dry solids) was prepared by mixing 11.5 kg of starch with 15.5 kg of water. Sodium chloride salt was mixed into the slurry in a conventional mixer in an amount of 10% based on total slurry weight (1 kg). The slurry was fed to a filter centrifuge, which was rotated at a centrifuge speed of 700 rpm, at a rate of 750 l/h. After all slurry was fed to the centrifuge, the centrifuge speed was increased to 1400 rpm and the filter cake was centrifuged for 10 min. The resulting blend had a moisture content of 35-42% based on total weight.

Inventive Example 1—Spray Salt Solution on Partially Dewatered Cake

[0099] A starch slurry (38% dry solids) was prepared by mixing 11.5 kg of starch with 15.5 kg of water. The starch slurry was fed to a filter centrifuge, which was rotated at a centrifuge speed of 700 rpm, at a rate of 350 l/h. After all slurry was fed to the centrifuge, the centrifuge speed was increased to 1400 rpm. Then, a salt solution (5 l of 5% sodium chloride) was sprayed over the filter cake over a period of about 30 min. Subsequently, the filter cake was centrifuged at 1400 rpm for another 5 min. The resulting blend had a moisture content of 35-42% based on total weight.

Inventive Example 2—Spray Salt Solution on Dewatered Cake

[0100] A starch slurry (38% dry solids) was prepared by mixing 11.5 kg of starch with 15.5 kg of water. The starch slurry was fed to a filter centrifuge, which was rotated at a centrifuge speed of 700 rpm, at a rate of 750 l/h. After all slurry was fed to the centrifuge, the centrifuge speed was increased to 1400 rpm. The filter cake was then dewatered by centrifuging at 1400 rpm for a period of 10 min. Then, a salt solution (5 l of 5% sodium chloride) was sprayed over the filter cake over a period of about 30 min. Subsequently, the filter cake was centrifuged at 1400 rpm for another 5 min. The resulting blend had a moisture content of 35-42% based on total weight.

Results

[0101] An overview of the Examples and the mass balance for each example is shown in Tables 1 and 2 below.

TABLE-US-00001 TABLE 1 Speed Salt Salt Salt slurry addition addition addition Salt feeding by by in slurry introduced (l/h) spraying spraying phase (g) CE1 350 10% of 2 kg 200 slurry CE2 350 10% of 1 kg 100 slurry CE3 750 10% of 1 kg 100 slurry IE1 350 51 of 5% 250 salt solution IE2 750 51 of 5% 250 salt solution

TABLE-US-00002 TABLE 2 Mass balance Starch Water Salt Water for for solution Cake Cake left in Filtrate slurry slurry sprayed weight moisture cake weight (kg) (kg) (l) (kg) (%) (kg) (kg) CE1 11.5 15.5 15.85 6.3 10.7 CE2 11.5 15.5 15.8 5.2 11.8 CE3 11.5 15.5 15.6 42 6.7 10.3 IE1 11.5 15.5 5 16 37 6.2 15.8 IE2 11.5 15.5 5 15.3 40 6.7 15.3

[0102] FIG. 2 shows the percentage of salt that is contained in the cake compared to what was introduced. In this figure Trial 15 option 1 corresponds to IE2, Trial 4 option 2 corresponds to IE1, Trial 16 option 3 corresponds to CE3, Trial 3 option 3 corresponds to CE2, and Trial 2 option 3 corresponds to CE1.

[0103] Homogeneity of the salt dispersion throughout the starch filter cake was measured by conductivity of the cake. Conductivity was measured at three different positions along the y-axis of the centrifuge as well as at the inner and outer surface of the cake. The results are shown in Tables 3, 4 and 5.

TABLE-US-00003 TABLE 3 Cake conductivity for CE3 Position in Cake Conductivity Conductivity Moisture centrifuge thickness of cake x = 0 of cake x = 4 cm cake (y-axis) (cm) (x-axis) (μS/cm) (μS/cm) (%) Top 4 1686 73 42 Middle 4  988 70 42 Bottom 4 2120 75 42

TABLE-US-00004 TABLE 4 Cake conductivity for IE1 Position in Cake Conductivity Moisture centrifuge thickness of cake x = 0 cake (y-axis) (cm) (x-axis) (μS/cm) (%) Top 4.5 3620 34 Bottom 3.5 6530 40

TABLE-US-00005 TABLE 5 Cake conductivity for IE2 Position in Cake Conductivity Conductivity Moisture centrifuge thickness of cake x = 0 of cake x = 4 cm cake (y-axis) (cm) (x-axis) (μS/cm) (μS/cm) (%) Top 4  511 103 40 Middle 4 1302 1279  40 Bottom 4 1109 704 40

[0104] These results show that the feeding flow of the slurry has an impact on the thickness and on the moisture of the filter cake. With a higher feeding flow (750 l/h) the cake has a better homogeneity in moisture and thickness.

[0105] Additionally, the starch filter cake has a better salt distribution with the salt addition by spraying according to the invention. Salt is present throughout the filter cake.

Inventive Example 3—Performing a Cationic Modification of a Native Wheat Starch

[0106] A starch slurry at 38% of dry solids was prepared by mixing 1100 g of native wheat starch with 1400 g of water, 55 g of sodium chloride (5% wNaCl/wstarch) was added to it. The pH of the slurry was adjusted to 11.6 with a 4% sodium hydroxide solution, the mixing occurred at 21° C. and under high level of stirring to ensure quick dispersion and avoid gelatinization of the starch.

The slurry was then fed to a filter centrifuge (model CEPA LS L3386), it was operating at 2100 rpm and dewatering took less than one minute. Immediately after the dewatering, 320 g of the spraying solution was prepared by mixing 68 g of a 60% 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPT) solution with 85 g of a 10% sodium hydroxide solution and 167 g of water. CHPT is transformed in the presence of NaOH into GMAC (glycidyl trimethylammonium chloride). The resulting solution is sprayed in the filter centrifuge on the filter cake with a spray bar using a pump (480-500 mL/min) within 1 minute, the centrifuge is then turned off. Finally, a piece of the wet cake (37-43% moisture) was sliced vertically, crumbled, mixed and dried (14% moisture), it was then stored in a closed vessel and placed in an oven set at 45° C. for 18 hours.

[0107] To determine the degree of substitution of cationic modified starch, the standard Kjeldahl method to study nitrogen content was performed, details of the technique and underlying methods are thoroughly explained in Sáez-Plaza, Purificación, et al. “An overview of the Kjeldahl method of nitrogen determination. Part I. Early history, chemistry of the procedure, and titrimetric finish.” Critical Reviews in Analytical Chemistry 43.4 (2013): 178-223 and in Sáez-Plaza, Purificación, et al. “An overview of the Kjeldahl method of nitrogen determination. Part II. Sample preparation, working scale, instrumental finish, and quality control.” Critical Reviews in Analytical Chemistry 43.4 (2013): 224-272.

[0108] In order to calculate the cationic degree of substitution in starch and therefore the yield, it was necessary to slightly adapt the procedure: remove all the unreacted chemicals by washing 30 g of the dry starch for 30 minutes with 1.5 L of a 70:30 ethanol and water solution. The washed sample was prepared for analysis following the Kjeldahl procedure for starch, known in prior art and in the referenced article. The analysis showed, after correcting for nitrogen content for the base material, a cationic degree of substitution of 0.012 mol cationic unit/mol anhydroglucose unit (reaction efficiency: 62%).

[0109] Moreover, literature reports comparable results in terms of efficiency for the same levels of substitution. BeMiller, J. N., & Whistler, R. L. (Eds.). (2009). “Starch: chemistry and technology”. Academic Press. Third Edition. Pages 632-635 mentions that wet processes, aiming at 0.02-0.05 degree of substitution, can achieve up to 70-85% reaction efficiencies for the same CHPT modification.

Inventive Example 5—Performing an Acid-thinning of a Native Corn Starch

[0110] A starch slurry at 41% of dry solids was prepared by mixing 1165 g of native corn starch with 1335 g of water. The 2.5 kg of slurry was kept under constant mixing to ensure an effective dispersion of the solids. Additionally, a 320 g of a diluted acid solution was prepared by mixing 91 g of a 3M solution of hydrochloric acid with 229 g of water.

[0111] The starch slurry was fed to a filter centrifuge (model CEPA LS L3386) operating at 2100 rpm and dewatering took less than one minute. Immediately after the dewatering the diluted acid solution was sprayed in the filter centrifuge on the filter cake with a spray bar using a pump (480-500 mL/min) within 1 minute. Finally, pieces of the wet cake (37-43% moisture) were sliced vertically, crumbled, mixed, stored in a closed vessel, placed in an oven at different temperatures (50° C. and 65° C.) and left to react for 6 and 18 hours. Final product moisture was between 11%-14%.

[0112] To assess the extent of thinning of the samples, the common approach is to measure the viscosity of the starch slurry, the viscometer Brabender Viscograph-E has been used for such analysis. Each sample was neutralized with sodium hydroxide until a pH of 6-7 and left to dry once again. Final product moisture was between 11%-14%. The dry products were slurrified (40 g of dry starch and 440 g of water), placed in the viscometer and viscosity profiles at different temperatures have been obtained. Table 6 and FIG. 3 display these results.

TABLE-US-00006 TABLE 6 Reaction conditions for different thinned starch samples. HCl REACTION REACTION CONTENT TEMPERATURE TIME SAMPLE (g.sub.HCl/kg.sub.starch) (° C.) (hours) Unmodified native — — — corn starch (CONTROL) Example 5A 4.5 50  6 Example 5B 4.5 65  6 Example 5C 4.5 50 18

Inventive Example 6—Performing Cross-linking on a Native Corn Starch

[0113] A starch slurry at 38% of dry solids was prepared by mixing 1100 g of native corn starch with 1400 g of water. 55 g of sodium chloride (5% wNaCl/wstarch) was also added to into the slurry. The pH of the slurry was adjusted to 11.5 with a 4% sodium hydroxide solution, the mixing occurred at 21° C. and under high level of stirring to ensure quick dispersion and avoid gelatinization of the starch. Additionally, 320 g of dilute spraying solutions were prepared by mixing different amounts (0.18 g-0.34 g) of sodium trimetaphosphate (STMP-cross linker) and topping up the rest of the weight with demineralized water.

[0114] The starch slurry was fed to a filter centrifuge (model CEPA LS L3386) operating at 2100 rpm and dewatering took less than one minute. Immediately after the dewatering the dilute STMP solution was sprayed in the filter centrifuge on the filter cake with a spray bar using a pump (480-500 mL/min) within 1 minute. Finally, pieces of the wet cake (37-43% moisture) were sliced vertically, crumbled, mixed, stored in a closed vessel, placed in an oven at 45° C. and left to react for 4 hours. Post to modification, the semi dry cake was slurrified, neutralized with hydrochloric acid until pH 6-7 and left to dry overnight. Final product moisture was between 11%-14%.

[0115] To assess the extent of crosslinking of the samples, the common approach is to measure the viscosity of the starch slurry, the viscometer Brabender Viscograph-E has been used for such analysis. The dry products were slurrified (40 g of dry starch and 440 g of water), placed in the viscometer and viscosity profiles at different temperatures have been obtained. Table 7 and FIG. 4 display these results.

TABLE-US-00007 STMP REACTION REACTION CONTENT TEMPERATURE TIME SAMPLE (ppm) (° C.) (hours) Unmodified native — — — corn starch (CONTROL) Example 6A 135 45 4 Example 6B 250 45 4

[0116] As can be observed in FIG. 4, the processes of Examples 6A and 6B successfully managed to create a link between molecular chains, as demonstrated by the shift in the hold viscosity and overall shape of the curve.

Inventive Example 7—Performing Oxidation on a Native Corn Starch

[0117] A starch slurry at 41% of dry solids was prepared by mixing 1165 g of native corn starch with 1335 g of water. The 2.5 kg of slurry was kept under constant mixing to ensure an effective dispersion of the solids. Additionally, 320 g of spray solutions were prepared by mixing different amounts (30.8 g-61.6 g) of a sodium hypochlorite solution (163 g of active chlorine per kilogram of NaOCl solution) and topping up the leftover volume with demineralized water.

[0118] The starch slurry was fed to a filter centrifuge (model CEPA LS L3386) operating at 2100 rpm and dewatering took less than one minute. Immediately after the dewatering the NaOCl solution was sprayed in the filter centrifuge on the filter cake with a spray bar using a pump (480-500 mL/min) within 1 minute. Finally, pieces of the wet cake (37-43% moisture) were sliced vertically, crumbled, mixed and left to react and dry overnight at room temperature. Final product moisture was between 11% -14%.

[0119] To assess the extent of oxidation in the samples, the common approach is to measure the viscosity of the starch slurry, the viscometer Brabender Viscograph-E has been used for such analysis. The dry products were slurrified (40 g of dry starch and 440 g of water), placed in the viscometer and viscosity profiles at different temperatures have been obtained. FIG. 3 displays these results.

[0120] Furthermore, the content of carboxyl groups has been measured using the procedure described by Kuakpetoon et al. [4]: 2 g of starch was mixed with 25 mL of 0.1N HCl solution and stirred for 30 minutes, the slurry was filtered through a paper filter and washed with 500 mL of demineralized water. The filtered wet cake was transferred to a beaker, 300 mL of demineralized water was added to it and the slurry was heated until complete gelatinization of the starch (95° C.). Afterwards, 150 mL of demineralized water was added to the slurry and the solution was titrated with 0.01N NaOH until pH 8.3, the whole procedure was repeated for a blank test with unmodified corn starch. The following equations were used to calculate the percentage of carboxyl groups:

m.sub.eq/100 g.sub.starch=([(V.sub.Sample−V.sub.Blank)×N.sub.NaOH×100])/(Sample.Weight)

%COOH=m.sub.eq/100g.sub.starch×0.045

[0121] With V.sub.Sample and V.sub.Blank expressed in milliliters and sample weight in grams.

[0122] By analyzing the data in FIG. 5, it is possible to see the shift of the pasting on-set from roughly 21 minutes for the native starch to roundabout 18 minutes in the most oxidized sample, also noticeable is the decrease in the slurry viscosity with increasing chlorine concentration. The carboxyl group content was measured for a separate sample containing 2% (20 g/kg) active chlorine, the analysis yielded 0.13% of COOH groups in the molecular starch matrix, a value very similar to the one reported by Kuakpetoon, Daris, and Ya-Jane Wang. “Characterization of different starches oxidized by hypochlorite.” Starch-Stärke 53.5 (2001): 211-218. (0.14% for 2% active chlorine via wet modification).