Question

Questions: a) To prevent the eggs from coagulating what is the highest temperature to cook the sauce? Use what we learned about eggs earlier to make an estimate. b) What kind of an emulsion is it: oil-in-water or water-in-oil? c) Calculate the volume fraction of butter from the ingredients list (1 oz butter = 30 ml, 1 egg yolk = 20 mL) 1 Tbsp = 15 mL. d) Assuming that one egg yolk has 2 g of lecithin of molecular weight 825 g/mole and each lecithin molecule has polar head group of area 1 nm2, calculate the total surface area of the lecithin from 3 eggs in this recipe. Assume that the lecithin spreads as a molecular film. How many droplets of radius 0.03 mm can this much lecithin coat? e) Is the emulsion elastic? If yes, then calculate elasticity using surface tension of σ = 20 x10-3 N/m and droplet radius 0.2 mm.

Answer 1

a) White eggs coagulate at 60°C (140°F). Heating an egg above 140°F could cook the egg.

b) Emulsion sources are made by mixing two substances that are not mixed normally. It is kind of oil in water emulsion.

d) 1 egg yolk = 2g of lecithin of molecular weight 825 g/mole. Area 1nm². Total surface area of lecithin from 3 eggs in this recipe.

Number of molecule in single yolk = (2/825) * 6 * 10²³ = 1.5 * 10²¹ molecules

Total droplet surface area protected is number of molecules * 1nm = 1850 yard²

Therefore, Area of droplet =