132 



of grams of potassium hydrate to neutralize the volalile acids in 100 grams 

 of butter fat, we have the following proportion: 



.005612 X 34.48 X 20 = 3.8G grams of K()H 



In order to calculate the molecular weight of the volatile acids, we first 

 calculate the weight of the soluble acids. To do this we make use of the 

 amount of insolu})le acid or Hohner Value. The per cent, of ins<)lul)!(' acid 

 was found to be 87.54, mean molecular weight 254.8. The molecular weight 

 of the glycerides of t^he insoluble acids would be (254.8)3 + 38 = 802.4 mean 

 molecular weight of the insoluble acids as triglycerides.'' 



Then from the following proportion we obtain the per cent., or parts per 

 hundred of the triglycerides of the insoluble acids. 764.4 : 802.3 :: 87.54: x, 

 X = 91.87 gram.s per hundred of glycerides of the insoluble acids. 



Now 100 — 91.87 = 8.13 glycerides of the soluble acids. Since 3KOH 

 = 92 parts of glycerol or 38 parts of CsH,, then from the quantity of KOH 

 reciuired to neutralize the soluble acids in 100 grams of fat. which was found 

 to be equal to 3.86 grams, we can calculate the per cent, of C^H^ combined 

 with the soluble acids by means of the following proportion; 186. 36:3. 86::38:y, 

 X = .87 per cent, of CsH.. If we subtract this fi'om the glycerides of the sol- 

 uble acid we have then the amount of soluble acids in 100 grams of butter fat. 



8.13— .87 = 7.26 

 and therefore the molecilar weight is determined from t lie following pro- 

 portion: 



x:56.12::7.26:3.86, x = 104.5 mean molecular of the \-olatile acids in this 

 sample of but ter fat. 



The mean molecular weight of the volatile acids of butter varies from 

 do to 130 as recorded by Richmond and Lewkowitsch. This is cjuite natural 

 and from the molecular weight of th(> differiMit volatile acids entei-ing into 

 the glycerids we can exjiect a \aiiation in the mean molecular wcigiit. .\ 

 slight variation of the diffei-enl acids would cause a marked iiuTcasc or de- 

 crease in the inean inolccular weight, 'i'iie niolecuiai' weights of the dilfei'cr.t 

 \()latile acids cnleritig into tlie glycei'ids we can e\|)ect a variation in the 

 mean nioh'cnlai- weight. This fact adds weight to (lie assumption tliat the 

 propoi-lion of xolalile acids are not eonst;uit. A slight \arialion of tlie dif- 

 ferent acids would cause a niai'ked increase or decrease in the mean molecular 

 weiglit. 'i'lie molecular weights of the different \oiatile acids enttM'ing into 

 the triglycerides of l)ntter fat .are ;is follows: 



'For (111' snprmilirali in ol' :i I . i ilvci-riili- In K ( >ll i< i-xpiosscl 1)\- llic fullouiii!: iMiiuil ion. 

 r,II.:u, I :i K oil ^ (':, H:.(()II), . K (H.H; !{,) 



IK, 

 M. \V, iif (Ml, = 41 .-. .(I - :! = :!Ssin c llic :! livilniicn mIdiiis an- lakcn liy llu' aciil.-. 



