Master of Science (MS)
Dairy Science (Animal, Dairy, and Poultry Sciences)
Steam frothing of milk is required to produce an acceptable foam for many espresso coffee drinks. Specific aspects of composition and processing may affect the foaming properties of milk. The aim of this study was to determine the effect of fat content, heat treatment, free fatty acid addition and storage time on the frothing properties of milk. The four treatments included: fat content (0.08% and 3.25%), pasteurization temperatures (171°F for 15 seconds and 210°F for 45 seconds), pre and post-pasteurization addition of lauric acid solution (0.0% and 2.0% of 0.5 M concentration) and storage time (1 and 10 days). For this experiment, 3 replicates were performed. For each treatment, 250 ml of milk was frothed with a Feama Espresso machine (model c85/1) using a 7.5-cm diameter graduated beaker for 25 seconds. For each treatment, frothing was repeated 5 times. Froth characteristics were observed and the steam froth value (SFV), amount of dissipation and foam volume were determined after 5 minutes. The free fatty acid level (µ equiv./ml) for all treatments were also determined prior to frothing. There was no interaction found between day and treatments. There was no significant difference (P≥0.05) found between day 1 and day 10 for SFV, foam volume, or dissipation based on fat level, pasteurization temperature, or free fatty acid addition. When all treatments over time were observed, there was a significant difference (P<0.05) in SFV and FFA level (µ equiv./ml). There was a significant difference (P<0.05) in SFV, foam volume and percent dissipation between all free fatty acid levels when all other factors were applied.
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Levy, Michael, "The effects of composition and processing of milk on foam characteristics as measured by steam frothing" (2003). LSU Master's Theses. 1017.
John U. McGregor