The influence of temperature and pressure factors in supercritical fluid extraction for optimizing nonpolar lipid extraction from buttermilk powder

Abstract 

The milk fat globule membrane, readily available in buttermilk, contains complex lipids claimed to be beneficial to humans. Phospholipids, including sphingolipids, exhibit antioxidative, anticarcinogenic, and antiatherogenic properties and have essential roles in numerous cell functions. Microfiltration coupled with supercritical fluid extraction (SFE) may provide a method for removing triacylglycerols while concentrating these nutritionally valuable lipids into a novel ingredient. Therefore, SFE as a method for phospholipid concentration needs to be optimized for triacylglycerol removal in buttermilk. The SFE conditions were assessed using a general full factorial design; the experimental factors were pressure (15, 25, and 35MPa) and temperature (40, 50, and 60°C). Particularly interesting is that only triacylglycerols were removed from buttermilk powder. Little to no protein loss or aggregation was observed compared with the untreated buttermilk powder. Calculated theoretical values showed a linear increase for lipid solubility as pressure, temperature, or both were increased; however, experimental values showed nonlinearity, as an effect of temperature. In addition, the particular SFE parameters of 35MPa and 50°C displayed enhanced extraction efficiency (70% total lipid reduction).

Key words: supercritical fluid extraction, milk fat globule membrane, milk phospholipid