15C-27 |
Influence of fatty acids and glycerol on the foaming properties of milk used in the manufacture of cappuccinos |
J. N. NANUA, L. F. Osorio, and J. U. McGregor. Dept. of Food Science & Human Nutrition, Clemson Univ., South Carolina Agriculture & Forestry Research System, 224 P&A Bldg., Clemson, SC 29631 Foam produced from the steam frothing of milk is an important attribute in the quality of cappuccinos. Fat hydrolysis may affect the foaming properties of milk but the individual contribution of the products of hydrolysis has not been documented. This study aims to identify the contribution of FFA, glycerol and monoglycerides to milk foam. Lauric acid and glycerol were added to skim and whole milk at a molar concentration of 0.005, 0.010 and 0.015 and evaluated in a 4 X 4 factorial treatment with four replications. Monoglycerides were added to the milk at the rate of 0.1, 0.2 and 0.3 %. Other milk samples were also stored for 15 days at 3± 0.5 șC and steam frothing value (SFV) determined after 0, 5, 10 and 15 days. The milk was cooled on ice for 10 min and frothed to 65 șC. The milk and froth were poured into a 250 ml measuring cylinder and allowed to settle for 3 minutes. The volume of the milk (LV) and total volume (TV) were recorded. SFV=100(TV-LV)/LV. Addition of FFA significantly reduced the SFV of the milk (P < 0.05). Mean SFV for whole and skim milk was 21.7% and 29.5% respectively and was reduced to 4.0% and 6.3% on addition of 0.015 molar lauric acid. Adding 0.1% Monoglycerides reduced the SFV to 5.8% and 8.5% respectively. Glycerol had no effect on the SFV. Storing milk for 15 days at 3 șC caused a slight decrease in the SFV of whole milk but caused a slight increase on the SFV of skim milk. The changes in SFV of milk during storage are being investigated further. This work indicates that only monoglycerides and FFA affect milk frothing. Control of milk fat hydrolysis can be used to influence the foaming properties of milk products.
Session 15C, Dairy Foods
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