The Component of Milk: A Lab Report on Physics of Food (Essay Sample)

The Component of Milk: A Lab Report on Physics of Food
From the slope of the time vs L2 graph calculate the diffusion coefficient D.
t= L2/ (πD)
t= R2/4D
t= 60 sec
R= 4.6
R2= (4.6)2= 21.16
Therefore, D is equal to;
4D*60= (21.16/4D) *4D
240D=21.16
D= 21.16/240 = 0.088167
How does the value of D that you obtained from the time vs L2 graph compare with the expected value of heat diffusion coefficient for cake batter?
t= L2/ (πD)
t= R2/4D
t= 60 sec
R= 0.377cm
R2= (0.377)2= 0.142129
Therefore, D is equal to;
4D*60= (0.142129/4D) *4D
240D=0.142129
D= 0.142129/240 = 0.0005922042
Therefore, the value of heat diffusion coefficient for cake batter which is 0.0005922042, is less that the calculated value of D= 0.088167
Use the value of D you measured and the actual distance to the center of the cake to redo part (c) of the pre lab and get the characteristic diffusion time
D= 0.088167
R= 4.6
t= R2/4D
t= (4.6)2/4*0.088167
t= 21.16/0.352668
t=59.999773158
t=60 sec
Compare your temperature measurements with those of the TF. How much do they agree or disagree?
At zero (0) minutes, my temperature measurement was 18.4oC while the TF temperature was 18.7oC, at this time, the difference between the two temperatures was only 0.3oC. After ten minutes, my temperature measurement was at 70oC while the TF temperature was 74oC. the difference between the two, after ten minutes was 4oC. The gap continued to widen with time. After fourteen minutes, T0 was 72oC while TF was already at 86oC (Pedersen & Myers, 2011). The difference between the two was 14oC. in just within a range of four minutes, the gap between T0 and TF had increased by 10oC. after fifteen minutes, T0 had risen to 78oC (Jorjadze, Pontani & Brujic, 2013). After one minute, the temperature had risen by 6oC. This is partly because the oven was getting hot with time and also because the cake was transitioning from uncooked to cooked. On the other hand, after fifteen minutes, the TF was at 99oC, having risen by 13oC within a period of one minute.
At what temperature does the cake transition from uncooked to cook—i.e. what temperature does the batter of the cake cook? Until what temperature does the chocolate remain molten, i.e. liquid?
The cake transitions from uncooked to cooked at 375 F.
Pre Lab
Which component of milk acts as the surfactant to stabilize the emulsion?
Milk contains lecithin, which is a phospholipid with both affinities for water (hydrophilic), and affinity for lipids (hydrophobic properties) which act as a surfactant (Jaber, Naterer & Dincer, 2010). Besides, milk contains Casein which is a flexible surfactant that also contains both hydrophilic and hydrophobic properties. It is present in milk both as calcium caseinate and calcium salt. (Pedersen & Myers, 2011) It is a mixture of kappa, beta, and alpha caseins which clumps together to form a precipitate called micelle. In most mammalian milk, casein makes up approximately 82% of the milk composition. It is responsible for stabilizing emulsions.
At what volume fraction does an emulsion behave like a solid?
An emulsion is a mixture of two immiscible liquids in which, one fluid is dispersed in another where, the former is stabilized in the latter by an amphiphilic substance. Although emulsions are liquid in nature, they have elastic responses which are similar in features to viscoelastic solids. At a pressure of (π), the fraction volume (Φ) of the droplets in an emulsion increases (Morse & Witten, 1993). When the pressure is sufficiently high, enough to compel the droplets to collide, the volume fraction (Φ) approaches one (Jaber, Naterer & Dincer, 2010). The subsequent increase in pressure leads to liquefaction or deformation of the droplets. Therefore, the volume fraction must be less than one for an emulsion to behave like a solid.
What is the difference between an emulsion and a foam?
Emulsions are mixtures of two fluids that in some cases, behave like solids. They are composed of discontinuous bubbles of gas that are partly suspended in a liquid (Jorjadze, Pontani & Brujic, 2013). On the other hand, a foam is made of a gas that is entrapped in a liquid or solid matrix.
Is ice cream an emulsion or a foam or both?
Ice cream is colloidal matrix that combines both a foam and an emulsion with air (gas, solid, and liquid), ice crystals, and milk fat that are evenly or unevenly dispersed throughout another liquid usually water from milk (Morse & Witten, 1993). Therefore, ice cream is both a foam and an emulsion.
Molten Chocolate cake questions:
Assume that the initial temperature of the cake batter is 20 °C and the oven is at 375 °F.
* Convert the oven temperature to °C.
32o F = 0oC
Therefore, 375 o F will be equal to 190.556°C.
* How do you expect the temperature to vary along a hori