Statement of Acheivement

The Indian in me needs to put this out.. ;D

Science of Gastronomy: Desserts

The word dessert comes from a French word 'dessevir', which means 'to clear the table'.

Cakes:
The elasticity of the cake dough is due to formation of gluten fibers. The stronger the fibers the more elastic the dough. Water makes gluten  fibers strong while oil, acid, sugar decrease the strength of gluten thus making the dough less elastic. Salt can make the fibers strong (this is probably why we add a little salt while making the dough in a cake).
Cakes become soft by introducing air bubbles inside the cake. This can be done using leavening agents such as baking powder, baking soda or yeast. Baking powder and baking soda are chemical leavening agents. The differences between the two can be found here. However chemical leavening agent can change the taste and color of the cakes. In this case biological leavening agent like yeasts are used. Yeast requires the right temperature and the correct nutrient like sugar for it to rise. However yeast releases carbon very slowly while the chemical leavening agents produce the air bubbles faster. The dough produced by yeast is more elastic while that produced by chemical agents is less strong. Thus yeast is used for food like bread while chemical agents are used for items like cakes. Yeasts also leave behind a distinct flavor. Butter and eggs add on to the color and the texture of the cakes.

Why do cakes 'sink' in the center?
This is because of variations in temperature.

• temperature too low, or cooking time too short.
• frequent opening of the oven door.
• too much liquid or too little flour. Steam condenses and causes the cake to collapse in the center.
• cooling time too long.

Souffles:

Factors affecting the texture of souffles include

• the type of eggs: old eggs give larger volumes but fresh eggs give more stable foam. eggs from the fridge give firm and good quality foam.
• egg yolk: they are low in water content, so cause the foam to dry out. Also the proteins are too stable to form foam.
• beaters: Multiple tines = better foam. Also if the beater keeps moving around the vessel then the foam will be better.
• ingredients like salt, water, vinegar and sugar. Salt decreases the stability of the foam and will also cause the foam to lose moisture dry out. But may be used for taste. Sugar increases the stability of the egg white foam. However we have to add it at the right time. Too early and a longer time is needed for the foam to form, too late and the foam will be dry. Vinegar makes the foam more stable. 
• incorporation of ions.

Custard:

Protein denaturation is a process that happens when you heat proteins. Denaturation is followed by protein coagulation which leads the food to thicken. This phenomenon is used in making custards etc.

Science of Gastronomy: Baking Soda vs Baking Powder

Baking powder and baking soda are leavening agents. Leavening agents form air bubbles inside cakes and breads thus making them spongy and soft.

Both of them contain sodium bicarbonate. Both of these rely on chemical reactions between acidic and alkaline compounds to produce carbon dioxide to  inflate dough or batter.

Baking soda:

• Contains only alkaline compound.
• When baking powder is added to water it dissolves completely. No bubbles are seen because of absence of acid in plain water.
• Can be added to dough only if the dough or batter contains acid for it to react to. 

Baking powder:

• Has both alkaline and acid compounds. Baking powder = Baking soda + Acid solids.
• When baking powder is added to water it dissolves immediately and tiny bubbles may be seen because of the acid reacting with water.
• Self raising. Does not need an acidic medium for it to work.

The Science of Gastronomy: Steak

For the past 4 weeks I have been on Coursera taking a class on Gastronomy. It has been interesting so far. The class which is taken by Professors from University of Hong Kong talks about the science behind cooking. Its like a professional version of the Alton Brown show.

Anyway for the past 2 weeks they have been talking about cooking the perfect steak. They started off with the anatomy of muscles. Felt like I was in my physiology class. Actin, myosin and the lot.

This week they spoke of choosing the perfect piece of steak. The three different types of steak meat- Prime, Choice and Select differ by the percentage of fat in them. Prime has the highest amount (10-13%) while Select has the lowest (2-4%). Choice has about 4-10%. Distribution of fat (marbling) in Prime is also more even compared to the other 2. More marbling the steak has the better it is.

The part of the animal body where the steak comes from is also important. If a muscle is used continuously like in legs etc, the muscle will have lots of fiber and sheath, so the meat will be tough. That is why the regions called tenderloin, sirloin etc are more preferred. [Note that same applies to other animals as well. Chicken breasts are more tender than thighs or legs]. 

For tough meat Physical or Chemical methods can be used to tenderize it.  Physical methods involve pounding or slicing and carving. Chemical methods involve use of Sodium bicarbonate (baking soda), marinating (with some acid, oil and herbs) or using meat tenderizer. These methods either increase the water content of the meat or cause disruption of muscle fibers. Baking soda has been known to be the best tenderizer. However note that baking soda can make food bitter. Thus one has to add a little sugar to neutralize the bitterness.

One more thing. Cutting along the meat fibers will make the meat tougher than cutting across the fibers. This is because cutting across the fibers breaks the fibers and makes the meat softer to chew.