Effect of Homogenization Temperature and Pressure on Lipoprotein Lipase Activity and Free Fatty Acids Accumulation in Milk

Abstract

This study demonstrated that homogenization did not increase the activity of lipoprotein lipase (LPL) in spite of a fast accumulation of free fatty acids (FFA). Two homogenization pressures (100 and 170 bar) and two temperatures (40<span style="font-family:宋体;font-size:9pt;"><span><span>℃</span></span></span>and 50<span style="font-family:宋体;font-size:9pt;"><span><span>℃</span></span></span>) were examined. The activity of LPL was analyzed and the formation of FFA was measured with two different methods, the B.D.I.-method and a nonesterified fatty acids (NEFA) method. A homogenization temperature of 50<span style="font-family:宋体;font-size:9pt;"><span><span>℃</span></span></span> resulted in a decreased LPL activity compared to 40<span style="font-family:宋体;font-size:9pt;"><span><span>℃</span></span></span>. No effect of homogenization pressure was found. Analyzing FFA concentration with the B.D.I.-method resulted in significant effect of homogenization temperature and no effect of pressure. The largest formation of FFA was found in milk homogenized at 40<span style="font-family:宋体;font-size:9pt;"><span><span>℃</span></span></span>. Using the NEFA method, another result was obtained, indicating no effect of homogenization temperature and a larger FFA accumulation at 100 bar than at 170 bar. Both analytic methods demonstrated significant production of FFA during 60 min incubation at homogenization temperature after treatment. The level of FFA in the milk samples immediately after homogenization was very high, demonstrating that LPL cleaves the triglycerides very rapidly when the native membrane was damaged. The regression between the B.D.I.-method and the NEFA was fair in the interval between 4 and 14 mmol/100 g fat, whereas at higher concentrations, the correlation was poor

Effects of changes in homogenization sequence and temperature for milk on physicochemical properties of stirred yoghurt

“…In the present study, increasing homogenization temperature led to a decrease in the D [4,3] and D [3,2] values and an increase in the specific surface area values of the milk. Similar to our results, Wiking and Dickow (2013) found that D [4,3] value of fat globules decreased by approximately 14%, when homogenization temperature of milk increased from 40 °C to 50 °C at 10 MPa, and the authors explained that decrease in viscosity of milk with increasing the homogenization temperature might cause the milk fat globules to become smaller due to the potentiating effect of homogenization at high temperature.…”

Effects of pressure, shear, temperature, and their interactions on selected milk quality attributes

“…This finding indicated the dominant role of thermal effects of UST treatment on lipase activity. In earlier studies where homogenization was performed at lesser pressures of 200 MPa (Datta et al, 2005) and 17 MPa (Wiking and Dickow, 2013), the lipase activity was observed to be reduced by increasing temperature. In the present study conducted at 400 MPa, the lipase activity of samples UST treated at 35°C were lesser than 65°C UST-treated samples.…”