1. Both egg white and whipping cream foams are air in liquid however, whipped cream foam is milk and sugar whipped together to incorporate air and an egg foam is an egg white whipped to incorporate air. The protein within the egg white surrounds the air bubbles in the liquid helping to stabilize the foam. The milk contains casein that also stabilizes the air bubbles within foam. The sugar in the milk helps to create stable foam by being part liquid phase and interacting at the interface layer.
The whipping cream contains fat and fat can interfere with the stabilizing and emulsifying properties, therefore egg white foam is more stable. Egg white foams can be stabilized at colder temperature because the proteins remain rigid, where room temperature and heating would cause the foam to collapse because the change in proteins’ shape (Christensen, 2009). Cooler temperatures also helps to create a better whipped cream foam because the fat globules clump together, allowing for more protein to stabilize air pockets (Brown, 2015). Room and Increasing temperature of whipped cream foams disperse the fat globules more, reducing the stability of the foam by reducing the amount of protein that can surround air pockets (Brown, 2015)
2. The different techniques used to create foams were interesting to say the least. The aquarium bubbler was the least stable because the air pockets were very large and were not stabilized. The whole foam collapsed after the two-minute mark. The most stable foams were created by traditional methods of electric whisk and hand held mixers. These foams retained their volume over a much longer time, showing their stability over time. The whipping siphon foam I think lost its charge after some time and deflated quickly once it began to lose its volume. The manual whisk can make a stable foam but no one would ever want to stand and whisk by hand when they could reduce there time and effort with an electric hand mixer.
3. A vaquelin is beaten egg white to form foam, with added water to increase the volume of the foam and sugar to increase the volume and stabilize it, which is microwaved to set tl o set the proteins. A single egg white will produce 300 mL of foam (Sanchez, 2015). When you add liquid to the foam, the volume increases and when the solids and liquid ratio is adjusted to 10% and microwaved, the proteins chemically jellify and stabilizes the physical structure so that it will hold its shape when cut into (Sanchez, 2015).
4. Traditional foams are fat, starch, egg, or protein foams made with stabilizers such as milk fat, gelatin, flour, egg yolk gel or egg white gel (Mauer, 2015). Tradition foams are made with usually gas, steam, or nitrous oxide by methods of whisking, siphoning, frying, fermentation, or seaming (Mauer, 2015). Modernist foams can be similar in being fat, starch or egg based or very different like methylcellulose or xanthan gum based because of the use of hydrocolloids. Methods to make modernist forms are usually by similar whisking or siphoning methods, however the gas is typically nitrous oxide (Mauer, 2015). There are a wide range of stabilizers used in modernist foams, from traditional to gums and gels. Modernist foam textures that cannot be created with traditional ingredients are the gum-based foams because of their stability and effect on viscosity that milk proteins and egg proteins will never be able to achieve on their own.
5. The hardest gel would be agar because it is very brittle and the strongest gel would be gellan because it is very elastic (Sanchez, 2015). The most slippery gel I would assume would be a soft, smooth gel like sodium alginate. a. Agar- firm, brittle, smooth* b. lota Carrageenan- soft, elastic C. Kappa carrageenan – firm, brittle d. Gellan (LA) – solid, firm, brittle (HA)- soft, elastic e. Guar Gum- stable, but not self gelling f. Lecithin – not self gelling, used as emulsifier to create elasticity g. Locust Bean Gum- elastic, soft, smooth mouthfeel h. Methylcellulose- stable, soft, elastic gel i. Pectin – jiggle, solid, soft, LM/HM determines thermoreversiblity j. Sodium alginate – solid, smooth, elastic, soft in presence of calcium k. Xanthan gum- viscous, soft, elastic gel with other agents *Descriptions of hydrocolloids from Lersch, 2010
6. Nitrous oxide aerates products by dissolving into fats, where carbon dioxide aerates by dissolving into water (Mauer, 2015). Nitrous oxide does not leave a taste and carbon dioxide causes the sensation of carbonation. The textures differ for these two gases because of the opposing phases they interact with, either oil or water. Two methods of modernist nitrous oxide uses are using a charging siphon to incorporate into potato starch for a baked potato like foam or with a charging siphon and low acyl gellan to make cauliflower foam. Two modernist ways of using carbon dioxide would be through making carbonated yogurt foams with a variety of gums or making carbonated cocktail foams.
7. Marshmallows made with gelatin hold their own shape and were much more stable than the ones made with methylcellulose. Since methylcellulose creates a softer gel do its thermoreversible nature, it is understandable that at warmer temperatures (such as our lab with all the burners heating up the room) it would be less stable than the gelatin marshmallows. After some time on the plate the methylcellulose marshmallows began to spread as thought.
8. Spherification is the process of a mixture with sodium alginate dropped into a liquid bath containing calcium ions. The calcium ions migrate into the sodium alginate mixture, creating a solid gel texture as the calcium ions form junction zones with the sodium alginate. Reverse spherification is when calcium is added to the mixture and the mixture is dropped into a bath containing sodium alginate. Reverse spherification produces a gel outer coating with a liquid middle because the alginate does not migrate into the sphere because of its size, therefore it only reacts with the outside exposed calcium ions.
I don’t remember the grape juice spheres working in class, but the pea ravioli was a forward spherification method that worked well. The texture was uniform throughout the entire ravioli (only the flavor was not yummy! ). I did experiment making orange juice spheres with reverse spherification and those worked as well. They had a popping boa-like texture when you broke the outer layer of gel in your mouth and the flavor of the orange juice was released. I was successful in creating a molecular gastronomy egg. The yolk was difficult to shape correctly and had a tail and the white was an interesting texture as well, being foam instead of a solid. I didn’t work of the courage to taste the makeshift egg because it was not the most appetizing looking egg in the world.
9. The liquid popcorn was an interesting twist of the night and really did look like the picture in Juan’s slides. There were buttery/creamy flavor to it with a slight sweet side as well. I would have never thought that someone could liquefy the flavors of popcorn but I was proven wrong.
10. The most interesting part of lab this week was just getting to play around with all the different reactions and understand how they worked. Alice and I played with different combination of fruit purees to try to get them to sphericate in the extra calcium bath we had made. The greatest failures of the night were our foams not setting up as well as we would have liked them too, however we did try using a faulty ISI charger. At the end of the night our failures were education for our final projects!
