Melting Point Of Fat Research Articles

The Determination of Melting Points in Human Fats

Summary.The “melting point” of fats generally means the upper limit of the temperature range through which the melting of the fat takes place, or, when determined according to empirical methods, a point very near this.When the melting point of human fats were determined according to the common methods the results were not reproducible.Therefore the melting process was investigated by following the changes during the melting process in some samples of human fat. It was found that the difficulties in the determinations on human fats were due to the characteristic that even several degrees below the real clear point only a very small fraction of solids is present. A fat as e. g. coconut oil has 3 per cent solids at 0.3° C beiow the upper limit of the melting range. In a human fat the solid fraction of 3 per cent was present at 6° C below the upper limit of the melting range. This means that the viscosity of this fat is low, even at a considerable distance below the “clear point”. Therefore the empirical “constants” which are characterized by a certain low viscosity of the sample, viz. the softening point, the slipping point etc. are found far from the clear point and varying much with small variations in the external conditions.When a sample of human fat to be used for melting point determination solidifies at 0° C heterogeneous crystals separate, which can produce large errors in the observed melting point. To avoid this the sample must be rapidly cooled down to an extremely low temperature (–70° C). In this way the fat solidifies as a microcrystalline mass which makes possible a relatively exact observation of the clear point. It was, by comparing with the dilatometric method, demonstrated that the clear point determined according to the author's procedure is really identical with the thermodynamically fixed upper limit of the melting range.The tendency of the fats to form unstable modifications with low melting points is discussed. Further it is demonstrated that srom a thermodynamical point of view the melting point and the folidifying point are identical.

The Rôle of Surface-Active Constituents Involved in the Foaming of Milk and Certain Milk Products. II. Whey, Skimmed Milk, and Their Counterparts

Summary Synthetic solutions of milk proteins and fat have been prepared which duplicate the essential foaming characteristics of whey and skim milk. Lactalbumin and milk fat were found to be the constituents that influence the foaming of whey. The constituents in milk or skim milk that determine its foaming properties are shown to be calcium caseinate, milk fat and lactalbumin. It is considered that calcium caseinate is preferentially adsorbed at the air/liquid interface at temperatures below the melting point of milk fat, lactalbumin being adsorbed at higher temperatures. The presence of milk fat globules is shown to be responsible for the minimum foaming of separated milk at certain temperatures. The addition of milk fat emulsion to blood serum brings about a minimum foaming at room temperatures. Previous work which is not in agreement with the present conclusion is analyzed in the light of the present studies.

Soft Curd Character Induced in Milk by Intense Sonic Vibration

Summary Reduction in the curd tension of milk was accomplished by flowing the fluid in a thin layer over electromagnetically driven diaphragm sources of intense sonic vibration. A study was made of the curd reducing effectiveness of oscillators operating at 1100, 1200, 2160, 3000, 610, and 360 cycles as related to original curd tension of the milk, temperature, time of exposure (velocity of flow), acoustic energy output, and variations in the mechanical features of the apparatus. The percentage reduction in curd tension was greatest in hard curd (60 grams and more) milks. Final curd values approached a constant level in the soft curd range no matter what the original curd texture. No reduction in curd tension was obtained in milk treated below 18° C. and very little at temperatures below the melting point of butter fat. It was found that one of the oscillators (360 cycle) was most efficient when the milk flow was maintained at 250 gallons per hour. With a sound output of about 900 watts more than 50 per cent reduction was attained. With the 360 cycle oscillator the degree of reduction in curd tension was found to bear a direct linear relationship to the power input up to 2000 watts when the velocity was 250 gallons per hour. This represents an output of about 18 watts per one per cent decrease in tension. Other oscillators at different frequencies showed much the same effectiveness with equivalent outputs per unit volume of milk. Hence differences in frequency were found to be negligible within the range explored. A direct relationship was found to exist between degree of fat dispersion and degree of curd tension reduction. The increased number of fat particles was shown to influence curd texture by weakening the curd matrix and by providing increased adsorptive area on which protein was fixed. Since but a small proportion of the total fat in milk need be finely subdivided to reduce the curd tension, a method was devised for producing soft curd milk by vibration without impairing the final cream volume.

SOME PROPERTIES OF ALKALOIDS IN RELATION TO CLIMATE OF HABITAT

Since the melting points of oils and fats have been found to vary in accordance with the climate of the habitats of the plants producing them, it is of interest to determine whether a similar condition exists in the case of alkaloids. If alkaloids have differences in melting points in accordance with their habitats, then concomitant variations would be expected in their molecular weights; percentage composition of carbon, hydrogen, nitrogen, and oxygen; structural formulae; solubility, and perhaps degree of toxicity.

An apparatus for approximate or comparative melting points of fats, waxes and petroleums

Journal of Oil and Fat IndustriesVolume 2, Issue 1 p. 28-30 Original Contributions An apparatus for approximate or comparative melting points of fats, waxes and petroleums Hoyt Stevens, Hoyt Stevens United Drug Co., St. Louis, Mo.Search for more papers by this author Hoyt Stevens, Hoyt Stevens United Drug Co., St. Louis, Mo.Search for more papers by this author First published: 01 January 1925 https://doi.org/10.1007/BF02635121AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume2, Issue1January 1925Pages 28-30 RelatedInformation

Apparatus for the routine determination of melting-points of fats and fatty acids

Apparatus for the routine determination of melting-points of fats and fatty acids