Fractionation of Anhydrous Milk Fat by Superficial Carbon Dioxide

Abstract

Milk fat was fractionated with supercritical CO* (SC-CO*) into 8 fractions at temperatures of 50" and 7O"C, over a pressure range of lo&350 bar. Two fractions (Ll and 2) were liquid, 3 fractions (1 I-3) were semi-solid and 3 fractions (Sl-3) were solid at 20°C. The peak melting temperature progressively increased (9.7" to 38.3"C) from fraction Ll to S3. The concentration of short chain (C24-C34) triglycerides decreased from fraction Ll to S3 while that of long chain (C42-C54) triglycerides increased gradually. The medium chain triglycerides were more concentrated in fractions L2 and 11-3. The proportion of short (C4-C8) and medium (ClO-C12) chain fatty acids decreased and that of long (C14-C18) chain fatty acids increased gradually from fraction Ll-S3. The weight average molecular weights and geometric mean-carbon number of milk fat fractions were in the range from 625.6 to 805.0 and 34.2 to 47.6, respectively, in comparison to 729.3 and 41 .O, respectively, for native milk fat, suggesting SC-CO* effected a fair degree of molecular weight separation. INTRODUCTIONMILK FAT has been used traditionally for the most part as butter, being the most important product in the dairy industry. Milk fat is a mixture of triglycerides of a range of molecular weights and degree of unsaturation, exhibiting a broad and variable melting range (Mulder and Walstra, 1974). The pleasing flavor of milk fat is among its most important advantages. However, its unique physical characteristics, especially its melting properties and plastic range do not suit it to a number of food-fat applications. Furthermore, the nature of feed and plan of nutrition of the cow affect the fatty acid composition and hence, milk fat characteristics (Jenness and Patton, 1959). Economic fractionation of milk fat into oil and plastic fat fractions which differ markedly from one another in chemical composition and physical characteristics will facilitate an increased utilization of milk fat in many food applications, such as confectionary and bakery products, and in creating convenient (e.g., frigo-spreadable) and dietetic (e.g., cholesterol-reduced or short and medium chain-triglyceride enriched) butter types. Differences in molecular weight, melting temperature (molecular weight and entropy of fusion), volatility and intermolecular interaction energy of constituent triglycerides, provide the physical property basis for separation of milk fat triglycerides.There has been a growing interest in supercritical gas extraction, over the past few years. Liquid-like densities of dense gases result in liquid like solvent powers. This property and faster mass transport characteristics relative to liquids due to low dense gas viscosity make dense fluids attractive extraction agents. Substances can be selectively dissolved by changing the density of the gas. Dense gas extraction involves the phenomena of distillation and extraction simultaneously (Zosel, 1978); enhancement of vapor pressure, ideal solubility and phase separation play a role. A mixture of compounds differin...

Effects of polar cosolvents on cocoa butter extraction using supercritical carbon dioxide

“…In this case, the amount of short-chain TGs decreased, whereas that of the long-chain TGs increased. This observation was also reported in a previous study (Arul, Boudreau, Makhlouf, Tardif, & Sahasrabudhe, 1987). The results indicate that the variation of POP composition was significantly (p b 0.05) higher when the extraction process was performed using 5% ethanol (Fig.…”

Fractionation of buffalo butter oil by supercritical carbon dioxide

“…As the pressure and temperature increased, higher densities (0.7-0.9 g/cm 3 ) of SC-CO 2 are achieved, thus the solvating power of SC-CO 2 is increased. Consequently, intermediate and higher molecular weight FAs commence migration into the supercritical phase (Arul et al, 1987). FAs composition trend found in this study was similar to that found in other researches (Hammam et al, 1991;Chen et al, 1992;Lim & Rizvi, 1995;Bhaskar et al, 1998).…”

“…In a homologous series of similar nature of intermolecular forces, the cohesive energy is a function of the molecular size. Volatility of TAG, therefore, decreases with increasing their molecular weight (Arul et al, 1987). Fractionation of TAG by SC-CO 2 involves the principles of solute-solvent interaction or affinity leading to miscibility of TAG with the SC-CO 2 phase.…”

“…Fractionation of BO with supercritical carbon dioxide (SC-CO 2 ) was carried out using a batchwise unit (Suprex 44, Suprex SFE Systems, Pittsburgh, PA), following the method of Arul, Boudreau, Makhlouf, Tardif, and Sahasrabudhe (1987). The extraction vessel (1.5 cm ID Â 10 cm long standard high pressure tubing) was packed with glass wool as a support, and then liquefied BO (3.0 g) was pipetted onto the glass wool.…”

Application of supercritical CO2 in lipid extraction – A review

“…Other important applications of SFE are decaffeination of tea, flavour extraction from herbs (Saldaña et al, 1999), extraction and fractionation of fats and oils (Arul et al, 1987;Froning et al, 1998;King, 2000;Hassan et al, 2001;Norulaini et al, 2004aNorulaini et al, ,b, 2009Zaidul, 2003;Zaidul et al, 2006Zaidul et al, , 2007a, cholesterol extraction (Chao et al, 1991;Froning et al, 1998), and dealcoholisation of alcoholic beverages (Señoráns et al, 2001). On a smaller scale, the extraction of aromas in juices (Spanos et al, 1993;Vega et al, 1996;Favati et al, 1998;Ollanketo et al, 2001), extraction of colourants, refinement of fats and oils, extraction of antioxidants (Tsuda et al, 1995;Fadel et al, 1999), deacidification of oil (Robin et al, 1996;Dunford and King, 2001), and inactivation of orange juice pectin esterase also have some importance (Palmer and Ting, 1995).…”