liming of Sugar Beet Cassettes - Vol
liming of Sugar Beet Cassettes - Vol liming of Sugar Beet Cassettes - Vol
VOL. 13, :"0. /, OCTOllER 1960 SAPONIFICATION OF BEET PECTIN 100 Cossettes treated with dry lime at 25° 80 c: o 60 '';; (\l u ;;:: c: o g- 40 tf) 20 Methoxyl 10 20 30 40 Time, minutes 569 Figure 3.-Saponification of beet pectin. Rate of de-esterification and deacetylation. Cossettes treated at 25 ° C with dry Ca(OH)2' Ul% on beets. acetic acid as a byproduct. Since demethylation is more rapid than deacetylation, it may be possible to restrict deacetylation and still stabilize pectin by sufficient demethylation. Processing Tests Several different processing procedures were eval uated by examining diffusion juice and thin juice from treated beets. Diffusion was carried out in a Brriniche-Olsen laboratory diffuser with a feed rate of 9 kg of beets per hour. First carbonation was continuous, in a Dorr-type laboratory carbonator (8). Thin juice was made by batch second carbonation of fihered first-carbonation juice. Cossettes were limed in the following four ways: I) dry Ca(OH)2 preliming, 2) lime slurry preliming, 3) direct liming in the diffuser, and 4) countercurrent washing with limed diffusion juice. Cossette liming was either at room temperature (less than 25 ° C) or at 40 ° C, using 0.4 to 1.0% CaO on beets. Diffusion temperature was 70 ' or 25 " C with alkaline beels, and was 70° C with limed beets 'which had been neutralized with
570 ] OCR:\AL OF THE . \. S. S. B. T. COe. Liming at 40 ° C was unsatisfactory because o[ pulp deterioration. Lime slurry treatments were difficult to manage because of the rapid extraction of sugar, even at low temperature. For continuous operation, a system of adding treatment liquor to the diffusion juice at a constant rate would be needed. Dry liming vvas easier, and still gave satisfactory treatment to the beets. Treatment levels above 0.4% CaO on beets were unnecessary. Diffusion juice from alkaline beets was clear and light colored. Juice from neutralized beets was darker, vvith more colloids, but still much lighter and clearer than normal diffusion juice. /\.11 of the diffusion juices were subjected to first carbonation, with additional lime. Sedimentation and filtration rates were determined on the first carbonation juices, and the color, lime salts, and purity of the second carbonation juices were measured. Table I is a summary of the results from the best three treatments. The major differences are in the total lime consumption and in the lime salts and total anions. The final mud volumes are a reflection of the amount of lime used. Table I.-Processing comparisons for prelimed beelS Cosseltcs limed at room temperature with dry Ca (HO)" (0.4% CaO on beets) Control Alkaline Nentral Preliming time, min. none 30 30 10 Diffusion temp.• · C. FiTSt carbonation: 70 2:; 70 70 I.ime added (% CaO on beets ) 2.0 0. 5 0.5 1.0 Sedimentation resistance 25 32 31 34 Mud volume ( % ) Second carbonation: 9.0 5.0 5.0 7.0 J.ime salts (CaO/IOO Bx) .05 .52 .39 .18 Anions (meq./IOO Bx) 31 50 55 51 Purity (%) Color (00/ 100 Bx) 91.6 2.0 The total lime consumption for the alkaline-diffused beets was 0.9 % , for the neutralized beets 1.4%, and for the control beets 2.0% GaO on beets. Lime salts and anions are high in the second carbonation juice from the limed beets because of acetate liberated from the pectin. The increase in total acids was matched by the increase in volatile acids, which we assume to be acetic acid. These excess anions prevent the removal of lime by carbonation without the addition of corresponding cations. The sodium carbonate needed to reduce the lime salts to the level of the control is calculated to be 0.05 to 0.15% on beets. The increase in anions, calculated as acetate, plus the increase in lime salts, calculated as calcium ion, is 1.3 to 1.7 grams per 100 89.5 2 . .0 90.2 2.8 90.0 2.8
570 ] OCR:\AL OF THE . \. S. S. B. T.<br />
COe. Liming at 40 ° C was unsatisfactory because o[ pulp deterioration.<br />
Lime slurry treatments were difficult to manage<br />
because <strong>of</strong> the rapid extraction <strong>of</strong> sugar, even at low temperature.<br />
For continuous operation, a system <strong>of</strong> adding treatment<br />
liquor to the diffusion juice at a constant rate would be needed.<br />
Dry <strong>liming</strong> vvas easier, and still gave satisfactory treatment to<br />
the beets. Treatment levels above 0.4% CaO on beets were<br />
unnecessary. Diffusion juice from alkaline beets was clear and<br />
light colored. Juice from neutralized beets was darker, vvith<br />
more colloids, but still much lighter and clearer than normal<br />
diffusion juice. /\.11 <strong>of</strong> the diffusion juices were subjected to<br />
first carbonation, with additional lime. Sedimentation and filtration<br />
rates were determined on the first carbonation juices, and<br />
the color, lime salts, and purity <strong>of</strong> the second carbonation juices<br />
were measured. Table I is a summary <strong>of</strong> the results from the<br />
best three treatments. The major differences are in the total<br />
lime consumption and in the lime salts and total anions. The<br />
final mud volumes are a reflection <strong>of</strong> the amount <strong>of</strong> lime used.<br />
Table I.-Processing comparisons for prelimed beelS<br />
Cosseltcs limed at room temperature with<br />
dry Ca (HO)" (0.4% CaO on beets)<br />
Control Alkaline Nentral<br />
Pre<strong>liming</strong> time, min. none 30 30 10<br />
Diffusion temp.• · C.<br />
FiTSt carbonation:<br />
70 2:; 70 70<br />
I.ime added (% CaO on beets ) 2.0 0. 5 0.5 1.0<br />
Sedimentation resistance 25 32 31 34<br />
Mud volume ( % )<br />
Second carbonation:<br />
9.0 5.0 5.0 7.0<br />
J.ime salts (CaO/IOO Bx) .05 .52 .39 .18<br />
Anions (meq./IOO Bx) 31 50 55 51<br />
Purity (%)<br />
Color (00/ 100 Bx)<br />
91.6<br />
2.0<br />
The total lime consumption for the alkaline-diffused beets was<br />
0.9 % , for the neutralized beets 1.4%, and for the control beets<br />
2.0% GaO on beets. Lime salts and anions are high in the second<br />
carbonation juice from the limed beets because <strong>of</strong> acetate liberated<br />
from the pectin. The increase in total acids was matched<br />
by the increase in volatile acids, which we assume to be acetic<br />
acid. These excess anions prevent the removal <strong>of</strong> lime by carbonation<br />
without the addition <strong>of</strong> corresponding cations. The<br />
sodium carbonate needed to reduce the lime salts to the level<br />
<strong>of</strong> the control is calculated to be 0.05 to 0.15% on beets. The<br />
increase in anions, calculated as acetate, plus the increase in<br />
lime salts, calculated as calcium ion, is 1.3 to 1.7 grams per 100<br />
89.5<br />
2 . .0<br />
90.2<br />
2.8<br />
90.0<br />
2.8
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