Chemical and physical properties of the high melting glyceride fractions of commercial margarines

Abstract

The fat obtained from nine commercial mar-garines purchased from Canada and the U.S.A. were crystallized from acetone at 15, 10, 5 and 0°C. The high melting triglyceride (HMG) fractions at 15°C contained high levels of palmitic and stearic acids. The 18:1 levels increased as fractionation temperature decreased. Triglyceride analysis re-vealed that the 11MG fractions contained high 1ev-els of carbon 54 and 52. The levels of trans iso-mers increased, whereas the trans levels in the 18:1 decreased with fractionation temperature. Mar-games made from canola oil exhibited β charac-teristics whereas canola-paim, soybean and corn margarines showed β¹ crystals. The fractions as crystallized from acetone, showed numerous X-ray short spacings, characteristic of β¹, β and in-termediate forms. Upon heating and cooling, the 15°C fraction showed β¹ or a and β¹ characteris-tics regardless of the polymorphic form present in the original margarines. The differential scan-ning calorimetry (DSC) melting points of these fractions varied from 53 to 50° C. The difference between the β and β¹ margarines could be related to the 16:0 and carbon 54 content of the 15°C frac-tion. In the β tending margarines the 16:0 content was below 11%, in the β¹ tending margarines above 17%. The carbon 54 content in the 15°C fraction of the β tending margarines was close to 70% and that of the β¹ tending margarines around 50%. The triglyceride C54 in the 15°C fraction is β tending and therefore should be kept as low as possible. In canola margarines this can be achieved by in-corporation of palm oil, preferably in a slightly hydrogenated form.