TOMATO PRODUCTS: PULP, KETCHUP, AND CHILI SAUCE TEXT

1.0383 | 8.90 | 1.0356 | 600.0 | 540 | 48.0 | 119.0 | 90.0 ---------+-------+----------+---------+------+---------+-------+------ The use of Table 11 gives a ketchup of medium concentration. Using this as a basis the manufacturer can decide the extent to which he should evaporate to secure a ketchup of the consistency desired and modify the table accordingly. Final concentration of the ketchup is controlled in the same manner as for pulp, either by a gauged tank or by specific gravity determination. If we start, therefore, with a given volume of partially concentrated cyclone juice and determine the solids present, we can in every case quickly ascertain from the appropriate table the number of gallons of finished product we should obtain, and the gauge stick or attached gauge glass will indicate when to stop evaporation in the tank. One advantage of measuring the original volume at the boiling temperature is that no temperature corrections are necessary, as both the initial and final temperature measurements are approximately the same. The final concentration may be controlled, as stated above, by determining the specific gravity of the finished product by one of the methods given under pulp (see page 33 and following). The determination of specific gravity at this point will probably give more accurate results than the use of a gauge stick, and is to be recommended for use with the finished product, provided the added constituents have been standardized. The method described on page 42 for determining the specific gravity of hot tomato pulp, may be used for obtaining the per cent of solids in the boiling cyclone juice in place of the Brix spindle reading on the filtrate. Table 11 for controlling the concentration of finished ketchup is based on the idea that there shall be a definite volume of partly concentrated pulp in the tank when the inflow of cyclone juice is stopped and the sample is taken for analysis. In this respect, this method of controlling the concentration of ketchup varies from the method described on page 54 for the control of the concentration of tomato pulp. It is sometimes convenient to secure this definite volume by filling the tank to a greater height than is desired and evaporating until the desired volume is secured. When this point is reached the sample of pulp is taken for specific gravity and steam is again turned on the tank. The Abbé refractometer may also be used for controlling the final concentration of the ketchup. This provides a very simple and quick method for determining the percentage of solids. It requires but a few drops of the filtered liquor from the ketchup to make the determination. The reading may be taken and the calculation made in one or two minutes’ time by use of Tables 13 and 14. The table for calculating the solids from the refractometer reading is Geerlig’s table for dry substance in sugar-house products, and is taken from the Methods of the Association of Official Agricultural Chemists, 1919. The entire table is not given but only the range over which it might possibly be desired to use it in the control of the manufacture of ketchup. The results by this method are only approximate, but are sufficiently accurate for manufacturing control. Table 12 gives a comparison of the solids obtained by drying in vacuum at 70° C. with results obtained by the refractometer. TABLE 12.—_Solids in Ketchup Obtained by Drying in Vacuum at 70° C. and by Abbé Refractometer from Geerlig’s Table_ +------------------------------+ | Solids in tomato ketchup | +----------------+-------------+ | By drying in | By Abbé | |vacuum at 70° C.|refractometer| +----------------+-------------+ | _Per cent_ | _Per cent_ | | 29.5 | 29.0 | | 30.0 | 29.4 | | 32.8 | 32.4 | | 28.0 | 27.9 | | 22.0 | 21.8 | | 27.7 | 28.0 | +----------------+-------------+ There are several errors in this determination which partially compensate for each other and give results fairly comparable with those obtained by drying. The refractometer of course determines only soluble constituents. Since salt gives a higher refractive reading than the same per cent of sugar, and since tomato solids give a higher refractive reading than the same percentage of sugar, and since any acetic acid of the vinegar is also read as solids on the refractometer, the total increase in reading due to these different factors nearly compensates for the insoluble solids of the ketchup. The variation of the per cent of solids as obtained by the refractometer from that obtained by drying will depend somewhat on the composition of the ketchup and in using the refractometer it is advisable to also determine the solids by drying on a few samples to obtain the relation between the two figures for that particular ketchup. TABLE 13.—_Refractive Index and Per Cent Solids in Tomato Ketchup_[21] ==========+======+=================== Refractive| Per | Decimals to be index | cent | added for |solids|fractional readings ----------+------+------------------- 1.3484 | 11 | 0.0001 = 0.05 1.3500 | 12 | 0.0002 = 0.1 1.3516 | 13 | 0.0003 = 0.2 1.3530 | 14 | 0.0004 = 0.25 1.3546 | 15 | 0.0005 = 0.3 | | 1.3562 | 16 | 0.0006 = 0.4 1.3578 | 17 | 0.0007 = 0.45 1.3594 | 18 | 0.0008 = 0.5 1.3611 | 19 | 0.0009 = 0.6 1.3627 | 20 | 0.0010 = 0.65 | | 1.3644 | 21 | 0.0011 = 0.7 1.3661 | 22 | 0.0012 = 0.75 1.3678 | 23 | 0.0013 = 0.8 1.3695 | 24 | 0.0014 = 0.85 1.3712 | 25 | 0.0015 = 0.9 1.3729 | 26 | 0.0016 = 0.95 | | 1.3746 | 27 | 0.0001 = 0.05 1.3764 | 28 | 0.0002 = 0.1 1.3782 | 29 | 0.0003 = 0.15 1.3800 | 30 | 0.0004 = 0.2 1.3818 | 31 | 0.0005 = 0.25 | | 1.3836 | 32 | 0.0006 = 0.3 1.3854 | 33 | 0.0007 = 0.35 1.3872 | 34 | 0.0008 = 0.4 1.3890 | 35 | 0.0009 = 0.45 1.3909 | 36 | 0.0010 = 0.5 | | 1.3928 | 37 | 0.0011 = 0.55 1.3947 | 38 | 0.0012 = 0.6 1.3966 | 39 | 0.0013 = 0.65 1.3984 | 40 | 0.0014 = 0.7 1.4003 | 41 | 0.0015 = 0.75 | | 0.0016 = 0.8 | | 0.0017 = 0.85 | | 0.0018 = 0.9 | | 0.0019 = 0.95 | | 0.0020 = 1.0 | | 0.0021 = 1.0 ----------+------+------------------- [21] Geerlig’s table for dry substance in sugar house products by Abbé refractometer at 28°C. In using Table 13, find the refractive index which is next lower than the reading actually obtained and note the corresponding whole number for the per cent of dry substance. Subtract the refractive index obtained from the table from the observed reading; the decimal percentages corresponding to this difference, as given in the column so marked, is added to the whole per cent of solids as first obtained. Correction must also be made for the temperature if above or below 28° C. The temperature correction is obtained from Table 14. For instance, suppose the refractive index was 1.3750 and that the temperature was 25° C. The per cent of solids as obtained from the table would be 27.2. The correction for temperature would amount to .14, which would be added to this reading, giving 27.34 as the per cent of solids. TABLE 14.—_Corrections for Temperature to be Used with Table 13_ ============+============================= | Per cent of solids. Temperature,+----+----+----+----+----+---- ° C. | 10 | 15 | 20 | 25 | 30 | 40 ------------+----+----+----+----+----+---- | To be subtracted +----+----+----+----+----+---- 20 |0.55|0.56|0.57|0.58|0.60|0.62 21 | .48| .49| .50| .51| .52| .54 22 | .42| .42| .42| .44| .45| .47 23 | .34| .35| .36| .37| .38| .39 24 | .27| .28| .28| .29| .30| .31 25 | .21| .21| .22| .22| .23| .23 26 | .13| .14| .14| .15| .15| .16 27 | .07| .07| .07| .07| .08| .08 +----+----+----+----+----+---- | To be added +----+----+----+----+----+---- 29 |0.07|0.07|0.07|0.07|0.08|0.08 30 | .13| .14| .14| .14| .15| .15 31 | .21| .21| .22| .22| .23| .23 32 | .27| .28| .28| .29| .30| .31 33 | .34| .35| .36| .37| .38| .39 34 | .42| .42| .43| .44| .45| .47 35 | .48| .49| .50| .51| .52| .54 ------------+----+----+----+----+----+---- Whether or not ketchup should be processed after filling into bottles depends on the conditions under which it is bottled. If the bottled product can be sealed at 180° F. or better a process is not necessary and is an unnecessary expense and waste of time, besides it may injure the color of the product. With the modern type of equipment it is possible to fill the bottles at a temperature which obviates sterilization. Care must be taken that the temperature of the ketchup in the receiving tank feeding the filler does not fall too low. Care must also be avoided in order not to fill the ketchup at too high a temperature as it results in excessive shrinkage of the contents. For ketchup filled at relatively low temperature a process should be used. The process necessary will depend upon the temperature at which the ketchup is filled and on the time that may elapse between filling and processing. Sanitary conditions of the factory and equipment are exceedingly important not only in relation to ease of sterilization but also in securing a product of good quality. In stacking ketchup it is best to stack the bottles upside down. This tends to prevent darkening of the ketchup in the neck of bottle, a condition known as “black neck.” It has been our experience that wherever this condition has occurred it is due to leakage of air into the bottles. Stacking bottles in this way undoubtedly keeps the cork of the cap moist and makes the seal more effective. CHILI SAUCE Chili sauce is of the same general character as ketchup but is made from peeled and cored tomatoes without removing the seeds, contains more sugar and onions and sometimes is made hotter than ketchup by the use of more cayenne pepper. There is a great variation among different manufacturers with respect to the methods of treating the tomatoes. Usually large to medium sized tomatoes are employed, separated from the small tomatoes which are used for making pulp and ketchup. Some manufacturers of chili sauce place the peeled and cored tomatoes directly into the kettle and mix the other ingredients without any form of breaking. Other manufacturers have various methods of breaking and crushing the tomatoes. Several crushers for this purpose are on the market and other means of breaking, such as meat choppers, meat cutters and apple graters are employed. Some convey the tomatoes from the peeling room to the kettle through a pump which breaks them up more or less. Because of the nature of the product there is no method available for testing the concentration of chili sauce and determining the point at which the cooking should be stopped. The refractometer may be used as a rough method of controlling the concentration. The percentage of solids as determined from the refractometer reading and Geerlig’s table is too low on account of the relatively high percentage of insoluble solids. However, a relation between the soluble solids and total solids may be obtained in this way which may be useful in controlling the concentration. The consistency of the product is always regulated by its appearance. The amount of cooking varies among different manufacturers but in general there is a concentration of from 40 to 45 per cent of the volume of the raw tomatoes employed. That is, 100 gallons of peeled and cored tomatoes yield from 40 to 45 gallons of chili sauce. The amount of onions added to chili sauce is substantially larger than the amount used with ketchup. Some manufacturers use approximately twice as much as the former. Hier[22] suggests 100 pounds of onions when used in the preparation of 100 gallons of chili sauce. Large onions should be used since they are more easily peeled and give less waste than smaller onions. They should be carefully peeled and should be finally chopped in order to safeguard against stopping up the tubes of the filling machine. [22] “The Manufacture of Tomato Products, 1919.” The cooking is substantially the same as with ketchup and the same ingredients are used with the exception of garlic which is not employed. Some manufacturers make the product rather mild, while others use substantially twice as much cayenne pepper as with ketchup. The same amount of salt and vinegar are employed with ketchup but substantially more sugar, some manufacturers using one-half more sugar than with ketchup. Because of its lumpy condition chili sauce affords more difficulty in filling into the bottle than is the case with ketchup. The bottle is also harder to seal. Its wide neck makes it more difficult to make the sealing tight than the smaller neck ketchup bottles, and the black rings in the top of the bottle are more frequent and more conspicuous than is the case with ketchup. The discussion of the processing given under ketchup (p. 70) is also applicable to chili sauce. PUBLICATIONS RESEARCH LABORATORY NATIONAL CANNERS ASSOCIATION BULLETINS *1 Some Safety Measures in Canning Factories *2 Swells and Springers (Superseded by Circular 6-L) *3 Tomato Pulp (Superseded by Bulletin 21-L) *4 Preliminary Bulletin on Canning *5 The Examination of Evaporated Milk *6 A cause of Dark Color in Canned Corn *7 Specific Gravity and Solids in Tomato Pulp (Superseded by Bulletin 21-L) *8 Exhaust and Vacuum *9 Processing and Process Devices *10 Lye Peeling 11 Deterioration in Asparagus 12 Washing Fruits and Vegetables 13 Washing and Cleaning Cans *14 Bacteriological Examination of Canned Foods 15 Suggestions for Canning Pork and Beans 16-L Heat Penetration in Processing Canned Foods 17-L Relation of Processing to the Acidity of Canned Foods 18-L Black Discoloration in Canned Corn *19-L Vitamins in Canned Foods 20-L The Effect of Hard Water in Canning Vegetables CIRCULARS *1-L Springers and Perforations in Canned Fruits 2-L The Discoloration of Lye Hominy 3-L Some Research Problems of the Canning Industry 4-L The Effect on Canned Foods of Industrial Wastes in the Water Supply 5-L Processing of Peas 6-L Swells and Springers 7-L Processing of String Beans and Beets 8-L Processing of Corn and Pumpkin * Out of print. Transcriber’s notes: In the text version, italics are represented by _underscores_, and bold and black letter text by =equals= symbols. Page p16 iris diaphrams — corrected to diaphragms. p16 Abbe condenser usually has an accent on the e — left as printed. p17 Compound miscroscope — corrected to microscope p17 There are two anchors for footnote 6 p21 Table 2 has been split into 3 sections because of its width. p22 Table 3 has been split into 3 sections because of its width. p23 Table 4 has been split into 2 sections because of its width. p25 Table 5 refractometer readings column needed to be shifted down one row starting between 5.60 and 5.66. p25 Table 5 The entry for specific gravity of the filtrate for a whole pulp reading in vacuo of 6.05 percent is given as 0.0235 — this has been corrected to 1.0235 p32 raw product it its — changed to it is. p60 value of of the pulp. — extra of removed. p68 refractometor — changed to refractometer