106 THE ANALYST. NEW METHOD FOR THE EXABIINATION O F BUTTER FOR FOREIGN FATS, BY DR. J. KOETTSTORFER. [We are indebted to Dr. Duprb, F.R.S., for the following important Translation from the Zeitschrift fiir dnalytische Chemie, von Dr. C. R. Fresenius, 1879, p. 199.1 THE analysis of butter, according to Angell and Hehner’s method, teaches us that this substance contains a far greater proportion of fatty acids with from ten atoms down- wards of carbon than had previously been assumed.Since most other fats contain only the higher fatty acids, and the lower ahids of the series have a smaller molecular weight than these, butter must contain more molecules of acid than an equal weight of mother fat, and from the above it mould appear that the difference in the number of molecules may be not inconsiderable.Therefore it seems feasible to estimate volumetrically the number of equivalents of acids contained in butter and other fats, from the amount of K H 0 necessary for complete saponification, and to distinguish butter from other fats by calculating the differences in potash used. In reality, this difference, as the experiments recorded below show, is such that it may be used for the detection of adulterated butter as readily as the difference between the insoluble fatty acids found in butter and in other fats. This new method for testing butter has the advantage over Angell and Hehner’s that it is much simpler and far more rapid of execution, since an analysis may be finished in half-an-hour, provided all necessary standard solutions are ready.The use of volumetric analysis in the examination of butter is not new. W. Heintz and Dupr6 * have already proposed, as modifications of Angell and Hehner’s method, estimating the soluble acids by titration. By my method, however, which is based on a dzerent principle, the whole of the acids contained in a fat are estimated by titration. The carrying out of the new metilod requires a standard hydrochloric acid and a standard alcoholic potash solution.I am in the habit of using half normal hydrochloric acid and a solution of K IT 0 in highly rectified spirit of about the same strength. As * DuprB’s method was published nearly two years before H&CZ’S.--EDITOBS AXALYBT.THE ANALYST. 107 indicator I use a dilute alcoholic solution of phenol-phtalein, as recommended by Dr.E. Luck, and always add the same quantity in each experiment. The examination of the fats is made as follows :-From 1 to 2 grammes of the fat, purified by melting and filtration, are weighed in a high beaker of about 70 C.C. capacity, 25 C.C. standard alcoholic potash are added, and the whole heated in a water-bath. When the dcohol is nearly boiling the mixture is stirred with a glass rod till all the fat is dissolved, which does not take more than a, minute.The glass rod is washed with a little alcohol and put into a safe place ; the beaker is covered with a, watch-glass and heated further for 15 minutes, in such a manner that the alcohol does not boil too violently. At the end of the quarter of an hour the watch-glass is washed with spirit and the alcoholic solution is stirred for one minute longer with the glass rod before used, so as to saponify any fat that might still adhere to it.The solution is now taken from the water-bath, 1 C.C. of alcoholic solution of phenol-phtalein is added, and it is titrated back with half normal hydrochloric acid. The point of neutrality is very sharply indicated, the liquid becoming pure yellow when changing to the acid re-ao tion.From the difference between the amounts of hydrochloric acid required by 25 C.C. standard alkali and the amount used in the above titration, the amount of E( H 0 combined with the acids of the fat is calculated. As regards the time of heating, I have convinced myself, by repeated experimenttr, that five minutes, as recommended by Aagell and Hehner, is not always sufficient- more particularly in the case of butter, but that a quarter of an hour is always enough to saponify fats completely and give uniform results. Since the titre of an alcoholic potash solution is always lowered slightly when if is heated with access of air in consequence of oxidation of the alcohol, it is advisable to standardise it by heating 25 C.C.for 15 minutes in a water-bath, as in the eaponi- fication of the fat, before testing with the standard acid. The difference between the heated and unheated potash solution amounts to from h t h to + C.C. normal hydrochloric acid. The titre of the potash solution diminishes by the same amount, in the course of five to six days, at ordinw temperature, owing to the oxidation of the alcohol, and it is therefore advisable to control the potash solution from time to time.Standard sulphuric acid cannot well be substituted for the hydrochloric acid, since this yields a precipitate of K,SO,, which masks the final re-action. The saturation capacity of the acids contained in a fat might be expressed in per cents. of KH 0 necessary for saponification.Since, however, 8s shown by the experiments given below, the errors of analyses of several samples of the same fat do not alter the figures in the first decimal, it may be better to convert them into full numbers, and calculate the amount of KHO used by 1000 parts of fat. In the following experiments, I therefore give the number of milligrammes of KH 0 which saponifv 1 gramme fat.SAMPLES OF BUTTER FROM TEIE NEIGHBOURHOOD OF FIUME. Substance 1.-1.224 grms. saponified K H 0 0.27868 p a . = on 1 grm. fat 227.7 rnillipu. H H 0. 9 , ,, 0'34584 ,, - 9 9 7, 227.5 97 9 , ,, ,, 0.32119 ,, - 9 , 9 , 227-1 f , ? ? 1.520 ,, 9 , ,, 0.28101 ,, - 7, 7, 227.4 1 , # I 1.317 ,, I , 9 , 0.29827 9, - 1 , , l 226.9 t 9 I t - - - 1.4145 ,, 1.236 ,, - Mean for 1 grm.fat 227.3 millignns, R H 0.108 THE ANALYST. Substance 2.-1,171 grms. saponified K H 0 0.26645 grms. = on 1 grm. fat 227.5 milligrms. K H 0. Mean for 1 grm. fat 227.2 milligrms. K H 0. Substance 3.-1,436 grms. saponified K H 0 0,32411 grms. = on 1 grm. fat 225.9 milligrms. K H 0. Mean fol' 1 grm. fat 225.7 milligrms. K H 0. Subrjtam 4.-1.403 grms. saponified K H 0 0.32556 gyms. = on 1 grm.fat 232.0 milligrms. K H 0. 99 9 , 9 , 226.8 9 , 1.395 ,, ,, 0,31712 ,, - - 1, - 1.481 ,, ? 9 ,, 0.33401 ,, =; :, 9 , 225.5 9, 9, 1.257 ,, 91 ,, 0.29266 ,, - $ 9 9 9 232.8 9 ) 9 , 1.237 ,, ,? ,, 0.28741 ,, L ! I I , 232.4 1, ,, - - Mean for 1 grm. fat 232.4 milligrms. K H 0. Substance 5.-1.451 grms. saponified K H 0 0-32847 grins. = on 1 grin.fat 226.4 milligrms, R H 0. 9 9 ,, 0.35293 ,, - 1, 9, 226.0 $ 9 9 9 1.470 ,, , l !, 0.33080 ,, - ,? ,, 225.8 1 , - - 1.562 ,, - Mean for 1 grm. fat 226.1 milligrms, K H 0. Substance 6 ~ 1 . 6 4 4 gmns. saponified K H 0 0.36546 grms. = on 1 grm. fat 222.3 milligrms. K H 0. Mean for 1 grm. fat 228.2 milligrms. K H 0. Substance 7.--1.885 grms. sapouitied 11 H 0 0,42632 grms. = 011 1 grm.fat 226.2 milligrms. K H 0. Mean for 1 grm. fat 226.5 milligrms. K H 0. Substance 8,--1.870 grms. saponified K H 0 0.41447 grms. = on 1 grm. fat 231.6 milligrms. K H 0. Mean for 1 grm. fat 221.8 milligrms. K H 0. Substance 9.--1.731 grms. sapollified K H 0 0.39691 grms. = on 1 grm. fat 229.3 milligrms. K H 0. Mean for 1 grm. fat 229.6 milligrms. K H 0. Subatance 10.-1-554 grms.saponified K H 0 0.36002 grms. = on 1 grm. fat 231.7 milligrms. K H 0. Mean for 1 grm. fat 231.3 milligrms. K H 0. 1.898 ,, ,? ,, 0.42137 ,, - 9 , 91 222.0 ,, 9 , - - 1,726 ,, ? 9 ,, 0.39137 ,? - 9, I , 226.8 9, 9, - - 10855 ,, $ 9 ,? 0.41176 ,, - 9, ,! 222.0 ,, 9, -... 1.759 ,, 9 1 ,, 0.40448 ,, - 9 , I > 229.9 ,, 9 , - 9, ,, 9 , 230.9 99 1.744 ,, ,, 0,40273 ,, - - 9 , Cladied butter from a reliable source from Upper Austria, by feeding with green clover, September- bbstance 11.--1.966 grms.saponified K H 0 0.43534 grms. = on 1 grm. fat 221.4 milligrms. K H 0. 1-524 ,, $ 9 ,, 0.33764 ,, - 9, 9 9 221.6 9, 9 , 0,662 ,, 9, ,, 0.14665 ,, - 7 , 9, 221.5 9 , 9, - - Mean for 1 grm. fat 221.5 milligrms. K H 0. Substance 12.--1.571 grms. saponified K H 0 0.35235 grms.= on 1 grm. fat 224.3 milligrms. K H 0. Mean for 1 grm. fat 224.4 milligrms. K H 0. Substance 13.-1*585 grms. saponified K H 0 0.35352 grms. = on 1 grm. fat 223.0 milligrms. K H 0. Mean for 1 grm. fat 223.3 milligrms. K H 0. If we take the clarified butter with the butters, the amount of K H 0 necessary for saponification varies in the thirteen estimations between 221.5 and 232.4 milligrammes for 1 gramme fat-a range of 10-9 milligrammes. Dr.U. Fleischmann has found 85-79 per cent. and 89.73 per cent. as the limits for the acids insoluble in water. If we compare these variations of butters with those found according to my method, they will be found nearly to agree ; since Clarified butter from same source, same feeding, October- 1.716 ,, 9 9 ,, 0,38526 ,, - 9, $ 9 224.5 3 , 9, - Clarified butter from same source, feeding with hay, November- 1.744 ,, I ! ,, 0.38992 ,, - 1, 1, 223.6 9 9 ? P - 221.5: 282.4 = 85-79 : 90.01.THE ANALYBT, 109 For comparison with butters, those fats used for the adulteration of melted butter, or for the manufacture of artificial butter, were examined. stearin, olein and palmitin. By calculation These generally contain 1 gramme steariu combines with 188.8 milligrammen K H 0.1 ,, olein ,, ,, 190.0 f 7 1 7 1 ,, palmitin ,, 9 , 208.0 9, $ 7 It was, therefore, to be expected that such fats would require less K H 0 for saponification than butter. This is found to be the case in the following analyses :- Beef dripping prepared in the laboratory :- Substance14.-lo269 grms.saponiiied K H 0 0.24985 grms. = on 1 grm. fat 196.9 milligrms. K H 0. ,, 0.28421 ,, - - 7 ) 9, 9, 196.1 7 9 9, ,, 0,29644 ,, - 9 , 7 , 196.7 I ? 1, 1.449 ,, 1.909 ,, 9, ,, 0.37448 ,, - 9 ) 9, 196.2 $ 9 1, 1.507 ,, 1 , - - Mean for 1 grm. fat 196.5 milligrms. K H 0. Substance 15.-1.820 grms. saponified K H 0 0.35788 grins. = on 1 grm. fat 196.6 milligrms. K H 0. Commercial tallow- 7 t ,, 0.27839 ,, - $9 ,, 196.9 7 , 9 ) 1.631 ,, 9 , ), 0.32119 ,, - $ 9 $ 9 196.9 3, 9, - I 1.414 ,, Mean for 1 grm.fat 196.8 rnilligrms. K H 0. Substance 16.--1.404 grms. saponified K H 0 0.27480 grms. = on I gym. fat 195.7 milligrms. K H 0. L a d , from kidneys, prepared in the laboratory- 9 , ), 0.26354 ,, - 9, ,, 196.1 9 , 9 7 1.658 ,, 3' ,, 0.32440 ,, - t , Y , 195.7 17 9, - - 1,344 Mean for 1 grm.fat 195.8 milligrms. K H 0. Substance 17.-1*544 grms. saponified K H 0 0.30256 grms. = on 1 grm. fat 196.0 milligrms. E H 0. Lard, from unsmoked bacon, prepared in the laboratory- 9 3 ,, 0.36031 ,, - 9 , $ 9 195.6 ?, 9 ) 1.751 7, ,, 0.34245 ,, - $ 9 ,? 195% 9 9 9 9 - * 1.791 ,, Mean for 1 grm. fat 195.7 milligrms. K H 0. Substmce 18.4.896 grms, saponified K H 0 0.36982 grms. = on 1 grm.fat 195.1 milligrms, E H 0. Commercial lard, professedly American- 1.991 7 , I? ,, 0.38963 ,, - 9, 9 8 195.7 9 9 19 - Mean for 1 gnu. fat 195.4 milligrms. K H 0. Substance 19.-1-608 grms. saponified I(. H 0 0.31653 grms. = on 1 grm. fat 196.9 milligrms, Tc H 0. Mutton dripping, prepared in the laboratory- 1.706 $, $ 9 ,) 093604 ,, - $ 9 $ 9 1974 9 , I? - Mean for 1 grm.fat 197.0 milligrms. K H 0. Substanoe 20.-1°647 grms. saponified K H 0 0.31653 grms. = on 1 grm. oil 192.2 milligrms. K H 0. Olive oil- $1 ,, 0.32644 ,, - $ 7 $ 9 191.7 ,, 1 ) 1-309 ,, 9 9 ,, 0.25068 ,, - 9 , ? y 191.5 $ 7 9 , - 1.703 Mean for 1 grm. fat 191.8 milligrms. I( H 0. Substanoe 21.--2.024 grms. saponified K H 0 0.36080 grms. = on 1 grm. oil 178.3 milligrms.K H 0. Colza oil- 9 , 9 , I , 179.0 1, 1.593 ,, ,, 0,28508 ,, -- - 9 , Mean for 1 grm. oil 178.7 milligrrns. K H 0. The maximum amount of K H 0 necessary for saponification is, according to the preceding analyses, for 1 gramme fat 197 milligrammes, and the difference from butter is lmge enough to be used for the approximate calculation of the percentage of other fats with whioh any given sample of butter may be adulterated.For exauple, in this110 THE ANALYST. plrtoe clarified butter is frequently mixed with lard. Two samples of clttrified butter bought in Fiume yielded the following results- Substance 22.-1.668 grms. saponified K H 0 0.37565 grms, = on 1 grm. fat 226.6 milligrms. I( H 0. 1.622 ,, ?, ,, 0,36779 ,, - 91 , I 226.8 $ 9 9 , - Mean for 1 g m .fat 226.7 milligrms, K H 0. Substame 23.--1.410 grms. saponified K H 0 0.30197 grms. = on 1 grm. fat 214.1 milligrms. K H 0. 9 , 91 Y , 214.5 9 9 1,390 ,) ,, 0.29819 ,, - - 9 , 9 , 9 , 213.6 3 , 1.625 ,, ,, 0,34711 ,, - - 1, $ 9 Mean for 1 grm. fat 214.1 milligrms. K H 0. This shows that the first of the two samples is unadulterated, the second dulterated clarified butter : for according to the previously given analyses of various kinds of butter the minimum amount of K H 0 necessary to saponify 1 gramme butter equals 221.5 milligrammes.Up to now I have, to my regret, been unable toprocure any so-calledoleo-margarin, from which, at present, most of the artificial butter is made. I have, however, received from Saxg some best Vienna Sparbutter (economical butter), made, according to the description which accompanied it, out of 50 kilos.oleo-Daxgarin and 26 litres milk. Since the proportion of butter which this amount of milk could add to the mixture is scarcely 1 per cent., the result of the examination of the fat will differ but slightly from that obtained from oleo-margarin. Oleo-margarin is obtained from beef tallow through separation of stearin.If we take into consideration the above given figures for stearin, olein and palmitin, one 8hodd expect that oleo-margarin, after the separation of stearin which combines with the smallest proportion of K H 0, would require more K H 0 for saponification than tallow. The examination of the economical butter yielded, however, the opposite result. Subattsnoe 24,-1.797 grms.saponified K H 0 0.35206 grms. = on 1 grm, fat 196-9 milligrams. K H 0. Best Vienna economical butter, from Sarg- 1-762 ,, 9 9 l , 0,34274 ,, - 9 , 9 1 195.6 $ 9 11 - Mean for 1 grm. fat 196.8 milligrams. K H 0. The addition of about 1 per cent. butter increases the amount of K H 0 necessary, by 0.2 to 0-3 milligramme; 1 gramme oleo-margarin, from which the sample of eaonomical butter was made, would therefore have required 195.5 milligrammes KH 0 for complete saponification.Beef tallow requires, according to the analyses given under NOS. 14 and 15, 187 7 milligrclmmes KH 0. It seems, therefore, that in the manufacture of oleo- margarin, somewhat more palmitin than stearin is separated: for, if Eltearin were chiefly removed, the oleo-margarin would require more & H 0 for saponification than tallow.As lmd, according to experiments 16, 17 and 18, requires nearly the same amount of KHO for saponification as oleo-margarin, and butter is moatly adulterated with these two substances, we may take the number 195.6 as the basis for calculating the amount of adulteration of a given sample of butter. According to the experiments given under Nos.1-18, the amount of K H 0 necessq to saponify 1 gramme butter or clarified butter, varies between 221-5 and 232.4 milligmmmes. We may, therefore, pass butter 118 pure, 1 gramme of whichTHE ANALYST, 211 requires 221.5 milligrammes or more of K H 0 for saponification, but as impure if it combines with less K H 0. For calculating the amount of admixed foreign fat, the mean of the two extreme values found for butter, namely 227, will probably be best.If we call X the percentage of admixed fat, and N the number of milligrammes of K H 0, which the sample of butter under examination requires for saponification, we obtain (227 - 195.5) : (227 -n) = 100 : x ; and x = (227 -n) x 3-17. In the calculation of the percentages of admixed foreign fats similar differences are found, owing to variations between various samples of butter, as in the method of Angell and Hehner.If, for example, in Calculating experiment No. 23, we take for butter the lowest figure, viz., 221.5 then X = 29 per cent. But if we take the highest, viz., 232.4, the result is 50 per cent., and by using the mean 227, the admixed foreign fat would come to 40 per cent.We might, therefore, if we calculate with the mean number of 227, make a mistake of 10 per cent. Under the most unfavourable condition, 29 per cent, foreign fat might escape detection ; namely, if butter which required 282.4 milligrammes KH 0 has been employed, and the adulterated butter =quires 221.5 milligrammes K H 0 for saponificdion. By using Angell and Hehner’s method, 40 per cent. might, under these conditions, escape detection. Irrespective of the ease with which butter may be examined by this new method, it will in some cases also furnish an insight into the constitution of fats. Besides this, this method may give a means of distinguishing between fats for which the proportions of K H 0 necessary for saponification differ sensibly. Thus, in the above experiments on olive oil and colza oil, the numbers 191.8 and 178.7 were obtthed, differing by 18.1. If once the extreme values have been fixed by a sufficient number of experiments for these two oils, we rnny use the difference between the numbers so fixed, not only for the detection of an adulteration of olive oil by colza oil, but also for calculating approximately the rmmount of adulteration. I reserve for a future time the continustion of the experiments on fats in thia direction, a d the publication of the results in due oourae. FIUME, Novenzber, 1878.