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A Method for Determining Lime in Dairy Products
A METHOD FOR DETERMINING LIME IN DAIRY PRODUCTS T. M O J O N N I E R
Research Laboratory, Mojonnier Brothers Company, Chicago, Illinois
In the course of studies upon the lime content of milk, it was found very desirable to have a simple and accurate method for making this determination. The following method was devised to fill this want. DESCRIPTION OF METHOD
Two variations of the method are possible: (1) Measure or preferably weigh the samples into clean Babcock test bottles. In all cases except when testing whole milk, add to the bottle sufficient distilled water to bring the total weight up to 18 grams. Mix samples with the water in the bottle very thoroughly. Now add slowly with constant shaking about 15 grams C. P. sulphuric acid; centrifuge for about ten minutes. Add sufficient distilled water to float off the fat. Centrifuge until the last visible traces of fat are gone, adding additional water if this might be required. Pour the solution into a beaker, and wash out the bottle with three successive small portions of distilled water. Add two volumes of 95 per cent grain alcohol, and allow to stand over night. Filter, using preferably, a Gooeh crucible with asbestos. Wash the precipitate by decantation, using grain alcohol. Dry thoroughly. Ignite at a moderate temperature, to a constant weight. If a filter paper is used, dry the precipitate in the filter and ignite together: (2) Transfer to a beaker the residue remaining in a Mojonnier fat extraction flask at the end of a fat extraction. Neutralize the ammonia carefully withC. P.sulphuric acid. Add 10 cc. in 453
454
T. MOJONNIER
addition to that required for neutralizing. Add two volumes of 95 per cent grain alcohol, and allow to stand over night. Proceed as under (1). SIZE OF SAMPLES RECOMMENDED
The size of sample to use can be varied with the method employed. Table 1 gives the amount recommended under the two methods. Slight variations will not effect the accuracy of the results. TABLE 1
Weight of santple recommended PRODUC~
Whole milk, skim milk, butter milk, and whey . . . . . . Evaporated milk, plain condensed whole and skim milk, ice cream mix, and cream . . . . . . . . . . . . . . . . . . . . Milk chocolate, cheese, malted milk, whole and skim milk powder, and butter . . . . . . . . . . . . . . . . . . . . . . . . . .
BABCO~ M]~THOD
MOJONNI~R M~THOD
~'6m8
0~¢vm~
18
10 5 1
EXPERIMENTAL EVIDENCE UPON THE ACCURACY OF THE METHOD
Ten grams of gypsum were heated to red heat. Weighed samples of this were ignited with filter paper, and found upon re-weighing to have undergone no change in weight. In another experiment a sample of gypsum was treated with sulphuric acid diluted 1-5, decanted, filtered, washed, dried in electric vacuum oven, and ignited t o constant weight. To about 0.1000 gram portions of this ignited product was now added 17 cc. of distilled water; 17 cc. of C. P. sulphuric acid, and after cooling, 100 ec. of 95 per cent alcohol. After standing over night, the precipitate was filtered, dried, ignited and weighed. The samples showed no loss in weight. m~S~L~S OBTAINE9BY THE ABOVE METHOD The results obtained by means of the above method in the ~ase of different dairy products are given in table 2.
DETERMINING LIME, IN DAIRY PRODUCTS
455
The method does not apply in the case of sweetened condensed milk or other products containing large amounts of sugar, on account of the solubility, of calcium sulphate in sucrose solutions. TABLE 2
Lime content of dairy products as found by abore method P E R C E N T CALCIUM O:XIDE NUMBER
1 2 3 4 5 6
7 8 9
10 11 12 13
OPERAI~OR
PRODUCT
Original Wh61e milk Evaporated milk Evaporated milk Evaporated milk Evaporated milk Evaporated milk Evaporated milk Evaporated milk Whole milk Powdered skim milk Butter milk Ice cream mix Cheese
0.122 0.284 0.306 0,344 O. 364 O. 288 O. 357 O. 371 O. 141 1.410 O. 159 O. 195
Duplicate 0.136 0.276 0.3O2 0.340 O. 361 O. 289 O. 354 O. 364 O, 141 1.420 O. 156 O. 188 0.969
Author Author Author Author Author Author Prof. H. C. Troy Prof. H. C. Troy Prof. H. C. Troy Prof. H. C. Troy H. Jo Liedel H. J. Liedel H. J. Liedel
CONCLUSIONS
The method described can be used to determine the lime content of all dairy products excepting those containing large amounts of sucrose. It is simple and accurate.
Research Laboratory, Mojonnier Brothers Company, Chicago, Illinois
In the course of studies upon the lime content of milk, it was found very desirable to have a simple and accurate method for making this determination. The following method was devised to fill this want. DESCRIPTION OF METHOD
Two variations of the method are possible: (1) Measure or preferably weigh the samples into clean Babcock test bottles. In all cases except when testing whole milk, add to the bottle sufficient distilled water to bring the total weight up to 18 grams. Mix samples with the water in the bottle very thoroughly. Now add slowly with constant shaking about 15 grams C. P. sulphuric acid; centrifuge for about ten minutes. Add sufficient distilled water to float off the fat. Centrifuge until the last visible traces of fat are gone, adding additional water if this might be required. Pour the solution into a beaker, and wash out the bottle with three successive small portions of distilled water. Add two volumes of 95 per cent grain alcohol, and allow to stand over night. Filter, using preferably, a Gooeh crucible with asbestos. Wash the precipitate by decantation, using grain alcohol. Dry thoroughly. Ignite at a moderate temperature, to a constant weight. If a filter paper is used, dry the precipitate in the filter and ignite together: (2) Transfer to a beaker the residue remaining in a Mojonnier fat extraction flask at the end of a fat extraction. Neutralize the ammonia carefully withC. P.sulphuric acid. Add 10 cc. in 453
454
T. MOJONNIER
addition to that required for neutralizing. Add two volumes of 95 per cent grain alcohol, and allow to stand over night. Proceed as under (1). SIZE OF SAMPLES RECOMMENDED
The size of sample to use can be varied with the method employed. Table 1 gives the amount recommended under the two methods. Slight variations will not effect the accuracy of the results. TABLE 1
Weight of santple recommended PRODUC~
Whole milk, skim milk, butter milk, and whey . . . . . . Evaporated milk, plain condensed whole and skim milk, ice cream mix, and cream . . . . . . . . . . . . . . . . . . . . Milk chocolate, cheese, malted milk, whole and skim milk powder, and butter . . . . . . . . . . . . . . . . . . . . . . . . . .
BABCO~ M]~THOD
MOJONNI~R M~THOD
~'6m8
0~¢vm~
18
10 5 1
EXPERIMENTAL EVIDENCE UPON THE ACCURACY OF THE METHOD
Ten grams of gypsum were heated to red heat. Weighed samples of this were ignited with filter paper, and found upon re-weighing to have undergone no change in weight. In another experiment a sample of gypsum was treated with sulphuric acid diluted 1-5, decanted, filtered, washed, dried in electric vacuum oven, and ignited t o constant weight. To about 0.1000 gram portions of this ignited product was now added 17 cc. of distilled water; 17 cc. of C. P. sulphuric acid, and after cooling, 100 ec. of 95 per cent alcohol. After standing over night, the precipitate was filtered, dried, ignited and weighed. The samples showed no loss in weight. m~S~L~S OBTAINE9BY THE ABOVE METHOD The results obtained by means of the above method in the ~ase of different dairy products are given in table 2.
DETERMINING LIME, IN DAIRY PRODUCTS
455
The method does not apply in the case of sweetened condensed milk or other products containing large amounts of sugar, on account of the solubility, of calcium sulphate in sucrose solutions. TABLE 2
Lime content of dairy products as found by abore method P E R C E N T CALCIUM O:XIDE NUMBER
1 2 3 4 5 6
7 8 9
10 11 12 13
OPERAI~OR
PRODUCT
Original Wh61e milk Evaporated milk Evaporated milk Evaporated milk Evaporated milk Evaporated milk Evaporated milk Evaporated milk Whole milk Powdered skim milk Butter milk Ice cream mix Cheese
0.122 0.284 0.306 0,344 O. 364 O. 288 O. 357 O. 371 O. 141 1.410 O. 159 O. 195
Duplicate 0.136 0.276 0.3O2 0.340 O. 361 O. 289 O. 354 O. 364 O, 141 1.420 O. 156 O. 188 0.969
Author Author Author Author Author Author Prof. H. C. Troy Prof. H. C. Troy Prof. H. C. Troy Prof. H. C. Troy H. Jo Liedel H. J. Liedel H. J. Liedel
CONCLUSIONS
The method described can be used to determine the lime content of all dairy products excepting those containing large amounts of sucrose. It is simple and accurate.