TOMATO PRODUCTS: PULP, KETCHUP, AND CHILI SAUCE TEXT

9.47 | 8.72 | 1.0395 | 8.45 | 7.51 | 49.2 | 1.0368 | 9.53 | 8.77 | 1.0397 | 8.50 | 7.55 | 49.4 | 1.0370 | | | | | | | | 9.58 | 8.83 | 1.0400 | 8.55 | 7.60 | 49.6 | 1.0372 | 9.64 | 8.88 | 1.0402 | 8.60 | 7.64 | 49.8 | 1.0374 | 9.70 | 8.93 | 1.0404 | 8.65 | 7.68 | 50.0 | 1.0376 | 9.75 | 8.98 | 1.0406 | 8.70 | 7.73 | 50.2 | 1.0379 | 9.80 | 9.03 | 1.0408 | 8.75 | 7.78 | 50.4 | 1.0381 | | | | | | | | 9.86 | 9.09 | 1.0410 | 8.80 | 7.82 | 50.7 | 1.0383 | 9.92 | 9.14 | 1.0413 | 8.85 | 7.86 | 50.9 | 1.0385 | 9.97 | 9.19 | 1.0415 | 8.90 | 7.91 | 51.1 | 1.0387 | 10.02 | 9.24 | 1.0417 | 8.95 | 7.95 | 51.3 | 1.0389 | 10.08 | 9.29 | 1.0419 | 9.00 | 8.00 | 51.5 | 1.0392 | ----------+----------+--------+----------+----------+---------+--------+ TABLE 5.—_Tomato Pulp and Filtered Liquor_—Continued ======================================================================== Whole pulp | Filtrate from pulp | ------------------------------+---------------------+---------+--------+ Solids by drying | | Solids by drying |Immersion| | ---------------------+ +---------------------+refract- | | _In vacuo_| At |Specific|_In vacuo_| At | ometer |Specific| at 70° C.| atmo- |gravity | at 70° C.| atmo- |reading | gravity| | spheric | at | | spheric | at | at | | pressure | 20° C. | | pressure |17.5° C. | 20° C.| | 100° C.| | | 100° C | | | ----------+----------+--------+----------+----------+---------+--------+ _Per cent_|_Per cent_| |_Per cent_|_Per cent_| | | 10.14 | 9.35 | 1.0421 | 9.05 | 8.05 | 51.7 | 1.0394 | 10.19 | 9.40 | 1.0424 | 9.10 | 8.09 | 51.9 | 1.0396 | 10.25 | 9.45 | 1.0426 | 9.15 | 8.13 | 52.1 | 1.0398 | 10.30 | 9.50 | 1.0428 | 9.20 | 8.18 | 52.3 | 1.0400 | 10.35 | 9.55 | 1.0430 | 9.25 | 8.22 | 52.5 | 1.0402 | | | | | | | | 10.41 | 9.60 | 1.0433 | 9.30 | 8.27 | 52.7 | 1.0404 | 10.47 | 9.65 | 1.0435 | 9.35 | 8.31 | 52.9 | 1.0406 | 10.52 | 9.70 | 1.0437 | 9.40 | 8.35 | 53.1 | 1.0409 | 10.58 | 9.75 | 1.0440 | 9.45 | 8.40 | 53.3 | 1.0411 | 10.64 | 9.80 | 1.0442 | 9.50 | 8.45 | 53.5 | 1.0413 | | | | | | | | 10.70 | 9.86 | 1.0444 | 9.55 | 8.49 | 53.7 | 1.0415 | 10.75 | 9.91 | 1.0447 | 9.60 | 8.53 | 53.9 | 1.0417 | 10.80 | 9.96 | 1.0449 | 9.65 | 8.58 | 54.1 | 1.0419 | 10.86 | 10.01 | 1.0451 | 9.70 | 8.62 | 54.3 | 1.0422 | 10.91 | 10.06 | 1.0453 | 9.75 | 8.67 | 54.5 | 1.0424 | | | | | | | | 10.97 | 10.11 | 1.0456 | 9.80 | 8.71 | 54.7 | 1.0426 | 11.02 | 10.16 | 1.0458 | 9.85 | 8.75 | 55.0 | 1.0428 | 11.08 | 10.21 | 1.0461 | 9.90 | 8.80 | 55.2 | 1.0430 | 11.14 | 10.26 | 1.0463 | 9.95 | 8.85 | 55.4 | 1.0433 | 11.20 | 10.31 | 1.0465 | 10.00 | 8.89 | 55.6 | 1.0435 | | | | | | | | 11.25 | 10.37 | 1.0467 | 10.05 | 8.93 | 55.8 | 1.0437 | 11.30 | 10.42 | 1.0469 | 10.10 | 8.98 | 56.0 | 1.0439 | 11.36 | 10.47 | 1.0472 | 10.15 | 9.02 | 56.2 | 1.0441 | 11.41 | 10.52 | 1.0474 | 10.20 | 9.07 | 56.4 | 1.0444 | 11.47 | 10.57 | 1.0476 | 10.25 | 9.11 | 56.6 | 1.0446 | | | | | | | | 11.53 | 10.63 | 1.0478 | 10.30 | 9.15 | 56.8 | 1.0448 | 11.59 | 10.68 | 1.0481 | 10.35 | 9.20 | 57.0 | 1.0450 | 11.64 | 10.73 | 1.0483 | 10.40 | 9.25 | 57.2 | 1.0452 | 11.70 | 10.78 | 1.0485 | 10.45 | 9.29 | 57.4 | 1.0454 | 11.75 | 10.83 | 1.0487 | 10.50 | 9.33 | 57.6 | 1.0457 | ----------+----------+--------+----------+----------+---------+--------+ TABLE 5.—_Tomato Pulp and Filtered Liquor_—Continued ======================================================================== Whole pulp | Filtrate from pulp | ------------------------------+---------------------+---------+--------+ Solids by drying | | Solids by drying |Immersion| | ---------------------+ +---------------------+refract- | | _In vacuo_| At |Specific|_In vacuo_| At | ometer |Specific| at 70° C.| atmo- |gravity | at 70° C.| atmo- |reading | gravity| | spheric | at | | spheric | at | at | | pressure | 20° C. | | pressure |17.5° C. | 20° C.| | 100° C.| | | 100° C | | | ----------+----------+--------+----------+----------+---------+--------+ _Per cent_|_Per cent_| |_Per cent_|_Per cent_| | | 11.81 | 10.89 | 1.0490 | 10.55 | 9.38 | 57.8 | 1.0459 | 11.87 | 10.94 | 1.0492 | 10.60 | 9.42 | 58.0 | 1.0461 | 11.93 | 10.99 | 1.0494 | 10.65 | 9.47 | 58.2 | 1.0463 | 11.99 | 11.04 | 1.0496 | 10.70 | 9.51 | 58.4 | 1.0465 | 12.05 | 11.09 | 1.0499 | 10.75 | 9.55 | 58.6 | 1.0467 | | | | | | | | 12.10 | 11.15 | 1.0501 | 10.80 | 9.60 | 58.8 | 1.0469 | 12.15 | 11.20 | 1.0503 | 10.85 | 9.65 | 59.0 | 1.0471 | 12.21 | 11.25 | 1.0505 | 10.90 | 9.70 | 59.2 | 1.047| | 12.26 | 11.30 | 1.0508 | 10.95 | 9.74 | 59.4 | 1.0476 | 12.32 | 11.35 | 1.0510 | 11.00 | 9.78 | 59.6 | 1.0478 | | | | | | | | 12.37 | 11.40 | 1.0512 | 11.05 | 9.82 | 59.9 | 1.0480 | 12.43 | 11.45 | 1.0515 | 11.10 | 9.87 | 60.1 | 1.0482 | 12.49 | 11.50 | 1.0517 | 11.15 | 9.92 | 60.3 | 1.0484 | 12.55 | 11.55 | 1.0519 | 11.20 | 9.96 | 60.5 | 1.0487 | 12.60 | 11.60 | 1.0522 | 11.25 | 10.00 | 60.7 | 1.0489 | | | | | | | | 12.65 | 11.66 | 1.0524 | 11.30 | 10.04 | 60.9 | 1.0491 | 12.71 | 11.71 | 1.0526 | 11.35 | 10.09 | 61.1 | 1.0493 | 12.77 | 11.76 | 1.0528 | 11.40 | 10.13 | 61.3 | 1.0495 | 12.83 | 11.81 | 1.0531 | 11.45 | 10.18 | 61.5 | 1.0498 | 12.88 | 11.86 | 1.0533 | 11.50 | 10.22 | 61.7 | 1.0500 | | | | | | | | 12.94 | 11.92 | 1.0535 | 11.55 | 10.27 | 61.9 | 1.0502 | 12.99 | 11.97 | 1.0538 | 11.60 | 10.31 | 62.1 | 1.0504 | 13.05 | 12.02 | 1.0540 | 11.65 | 10.35 | 62.3 | 1.0506 | 13.10 | 12.07 | 1.0542 | 11.70 | 10.40 | 62.5 | 1.0508 | 13.16 | 12.12 | 1.0544 | 11.75 | 10.45 | 62.7 | 1.0511 | | | | | | | | 13.22 | 12.18 | 1.0547 | 11.80 | 10.49 | 62.9 | 1.0513 | 13.27 | 12.23 | 1.0549 | 11.85 | 10.53 | 63.1 | 1.0515 | 13.32 | 12.28 | 1.0551 | 11.90 | 10.58 | 63.3 | 1.0517 | 13.38 | 12.33 | 1.0554 | 11.95 | 10.63 | 63.5 | 1.0519 | 13.44 | 12.38 | 1.0556 | 12.00 | 10.67 | 63.7 | 1.0521 | ----------+----------+--------+----------+----------+---------+--------+ TABLE 5.—_Tomato Pulp and Filtered Liquor_—Continued ======================================================================== Whole pulp | Filtrate from pulp | ------------------------------+---------------------+---------+--------+ Solids by drying | | Solids by drying |Immersion| | ---------------------+ +---------------------+refract- | | _In vacuo_| At |Specific|_In vacuo_| At | ometer |Specific| at 70° C.| atmo- |gravity | at 70° C.| atmo- |reading | gravity| | spheric | at | | spheric | at | at | | pressure | 20° C. | | pressure |17.5° C. | 20° C.| | 100° C.| | | 100° C | | | ----------+----------+--------+----------+----------+---------+--------+ _Per cent_|_Per cent_| |_Per cent_|_Per cent_| | | 13.50 | 12.44 | 1.0558 | 12.05 | 10.71 | 64.0 | 1.0523 | 13.55 | 12.49 | 1.0560 | 12.10 | 10.75 | 64.2 | 1.0525 | 13.60 | 12.54 | 1.0562 | 12.15 | 10.80 | 64.4 | 1.0527 | 13.66 | 12.59 | 1.0565 | 12.20 | 10.84 | 64.6 | 1.0529 | 13.72 | 12.64 | 1.0567 | 12.25 | 10.89 | 64.8 | 1.0531 | | | | | | | | 13.78 | 12.70 | 1.0569 | 12.30 | 10.94 | 65.0 | 1.0533 | 13.83 | 12.75 | 1.0572 | 12.35 | 10.98 | 65.2 | 1.0535 | 13.89 | 12.80 | 1.0574 | 12.40 | 11.02 | 65.4 | 1.0537 | 13.95 | 12.85 | 1.0576 | 12.45 | 11.07 | 65.6 | 1.0539 | 14.01 | 12.90 | 1.0579 | 12.50 | 11.11 | 65.8 | 1.0541 | -----------------------------------------------------------------------+ The per cent of solids in the filtered liquor obtained by drying _in_ _vacuo_, multiplied by 1.12, gives the per cent of solids in the original pulp obtained by drying _in vacuo_. This relationship is shown in Table 2, in the column headed “Ratio of pulp solids to filtrate solids,” and also in Table 5. Of the 33 samples shown in Table 2, the result obtained by multiplying the per cent of solids in the filtrate (obtained by drying _in vacuo_) by the factor 1.12 is very nearly identical with the per cent of solids in the pulp (obtained by drying _in vacuo_). In 22 of the 33 samples the difference between these two figures is less than 0.1 per cent. In 17 samples it is less than 0.06 per cent, and in 13 samples it is less than 0.05 per cent. In only two samples does it exceed 0.17 per cent. (_b_) _By calculation from the specific gravity of the filtrate._—The specific gravity of the filtered liquor may be determined by means of an ordinary pycnometer. From the specific gravity at 20° C., the per cent of solids in the filtrate as determined by drying _in vacuo_ at 70° C. may be obtained from Table 5. It may also be calculated by the following formula, which was derived from the same table: Per cent Solids in Filtrate = 230 (sp. gr. of filtrate - 1.000). The per cent of solids in the pulp may also be ascertained from the specific gravity of the filtrate at 20° C., from Table 5. The same results may be obtained from the following formula, which was derived from Table 4: Per cent Solids in Pulp = 257.5 (sp. gr. of filtrate at 20° C. - 1.000). It is of interest to note that the table suggested by Windisch for the determination of extract in wine (Bureau of Chemistry, U. S. Dept. Agri., Bull. 107, revised, Table V) may be employed to determine solids in tomato pulp from the specific gravity of the filtered liquor from the same. If the specific gravity of the liquor be determined at 20° C., the figures in the adjoining column, under “Extract,” correspond very closely to the per cent of total solids in the original pulp. A still closer agreement is obtained if the figure 0.05 be deducted from the percentage of extract given in the table. (_c_) _By calculation from the index of refraction of the filtrate._—The index of refraction of the liquor obtained by filtering tomato pulp may be determined by means of either the Zeiss-Abbé refractometer, or the immersion refractometer at the temperature of 17.5° C. The latter is preferable as it permits of much greater accuracy. The corresponding percentage of solids in the filtrate and the percentage of solids in the pulp from which it is prepared may be ascertained from the index of refraction by Table 5. The per cent of solids in the filtrate may also be calculated from the scale reading of the immersion refractometer at 17.5° C. by the following formula, which is derived from Table 5: Per cent Solids in Filtrate = 0.258 (scale reading - 15) - 0.0165(scale reading - 26.4). If the index of refraction has been determined by means of an Abbé refractometer, the per cent of solids in the filtrate may be calculated by the following formula: Per cent Solids in Filtrate = 666(n_{D} - 1.3332) - 20.7(n_{D} - 1.3376). The per cent of total solids in tomato pulp may also be ascertained from the index of refraction of the liquor prepared by filtering the pulp as shown in Table 5; or it may be calculated from the immersion refractometer reading by the following formula, which is derived from Table 5: Per cent Solids in Pulp = 0.289(scale reading of filtrate - 15) - 0.0185(scale reading - 26.4). If the index of refraction of the filtrate has been determined by means of an Abbé refractometer, the per cent of solids in the pulp may be calculated by the following formula: Per cent Solids in Pulp = 748(n_{D} - 1.3332) - 25.5(n_{D} - 1.3376). It is of interest to note that the relation between the index of refraction of the liquor obtained by filtering tomato pulp and the per cent of solids in that liquid is very similar to the relation between the index of refraction and dissolved solids in beer and wine extract, as shown in the table prepared by Wagner.[12] [12] “Ueber quantitative Bestimmungen wässeriger Lösungen mit dem Zeiss-schen Eintauch-refraktometer,” Table XVII. In the formula given above, as well as in Table 5, it is assumed that salt is absent. If it be desired to calculate the percentage of solids in a sample containing salt from the index of refraction of the filtrate, it is necessary first to determine the amount of salt present and make correction therefor (see p. 34). For this purpose the table of Wagner[13] may be employed. The correction of the immersion refractometer reading amounts to 0.45 for each tenth per cent of salt present. [13] _Ibid._, Table I. This correction is necessary if the percentage of solids be determined by drying, or calculated from specific gravity. Determination of Insoluble Solids Transfer 20 grams of the pulp to an eight-ounce nursing bottle, nearly filled with hot water, mix by shaking, and centrifuge until the insoluble matter is collected in a cake in the bottom of the bottle. Transfer the supernatant liquor onto a double, tared filter paper covering the bottom of a Büchner funnel, using suction to facilitate filtration. Again fill the nursing bottle with hot water, stir the cake of insoluble solids so that it is thoroughly mixed with the water, centrifuge, and decant the supernatant liquor on the filter. Repeat the centrifuging and the filtration of the supernatant liquor once more, and then finally transfer the insoluble solids to the filter paper and thoroughly wash with hot water. Dry the paper and insoluble solids, and weigh. The insoluble solids are quite hydroscopic and the weight must be taken quickly. Determination of Sugar The sugar of tomatoes is probably always present as invert sugar. If cane sugar is ever present in the raw product it is doubtless inverted during the concentration of pulp. The per cent of sugar given in Tables 2 and 3 was determined by the method of Munson and Walker.[14] [14] Methods of Analysis of the Association of Official Agricultural Chemists (1919). Determination of Acidity Accurate results cannot be obtained by the titration of tomato products in the presence of the insoluble solids. If it be desired to determine the acidity in the entire sample of tomatoes or tomato pulp rather than in the expressed juice, the insoluble solids should first be removed by the method given in the determination of insoluble solids or by filtration through filter paper. The per cent of acid given in Tables 2 and 3 was obtained by titrating the liquor obtained by filtering the pulp. In products of this nature, the addition of an alkali causes a brownish color which has a tendency to obscure the end point shown by the indicator. To obviate this, the sample should be diluted to at least 200 cc. and a larger amount of indicator employed than is necessary with a clear solution. The following details are suggested. Dilute 20 grams of the filtrate under examination with over 200 cc. of water. Add at ½ cc. of phenolphthalein solution (prepared by dissolving 1 gram of phenolphthalein in 100 cc. of 95 per cent alcohol) and titrate with sodium hydroxide until the end point is obtained. Add 1 cc. of tenth-normal hydrochloric acid, heat the solution quickly to boiling and boil one minute to expel carbon dioxide. Cool the solution quickly to about room temperature, and then add tenth-normal sodium hydroxide until the end point is obtained. The volume of hydrochloric acid added must, of course, be taken into consideration in the final result. The filtrate may also be titrated direct with tenth-normal sodium hydroxide solution with satisfactory results. Determination of Salt This laboratory has been using the following rapid method which gives results agreeing closely with results obtained by the analysis of the ash: Weigh out 20 grams of pulp, dilute in a volumetric flask to 200 cc., filter and titrate an aliquot portion with standard silver nitrate solution, using potassium chromate as indicator. The acidity of tomato pulp is not sufficient to interfere with this determination. DETERMINATION OF SPECIFIC GRAVITY[15] [15] All specific gravities given in this bulletin are on a 20°C/20°C basis. The specific gravity of tomato pulp is used as one criterion for establishing the value of pulp that is offered for sale and is also used in connection with the manufacture of pulp to determine the point at which evaporation should be stopped. In the former case there is ample time for making the examination, and conditions may be established which permit a reasonable degree of accuracy in the work. In the determination of the specific gravity of hot pulp during the process of its evaporation speed is essential, and the conditions of a manufacturing plant do not always permit a high degree of accuracy. It becomes necessary, therefore, to consider what methods may give the highest degree of accuracy obtainable under the conditions of the work and at the same time afford quick results. Tomato pulp, owing to its high viscosity, retains a large quantity of air bubbles which increase the volume of the pulp and hence interfere with the accuracy of the determination of specific gravity. In working with cold pulp this air may be eliminated by whirling in a centrifuge. With hot pulp that operation is impossible, and the specific gravity must be determined in the presence of the air bubbles mentioned. Moreover, in working with cold pulp the temperature can be more accurately controlled, and the error caused by variation in temperature can be corrected. With hot pulp these conditions cannot be obtained nearly so well. The determination of specific gravity of hot pulp is therefore only roughly approximate at best. Where time permits it is