kitchen and chemistry

As you can imagine , I love sweets ( but don´t worry there will be also salty dishes ) .I have had some requests so we have 2 recipes this week .This is my own creation ; now we can start with the main pourpose of this blog : apply chemistry in the kitchen .If you have ever baked a cake ( and you are not a skilled chef ) certainly you know the result is not always predictable .The main question is : will it swell ?
The normal baking powder contain mainly 2 substances : an acid and a base which reacts to give carbon dioxide .The alkaline component is almost universally sodium acid carbonate or sodium bicarbonate , the acidi could be tartaric acid or sodium pyrofosfate , which are both fast acting acid salts .(There are other powder containing acidic subsatnces which reacts at high temperature such as sodium aluminum sulfate ) .The acid-base reactions are known as the faster chemical reactions , so when you wet the powder , it suddenly give rais CO2 .That is the thing : we want the gas to rais and expand only when the batter is set enough to prevent the escaping or coalescence of the bubbles , this process can take a long time because the heat transfering in the oven is very slow .So I have planed a way to have a somewhat hardened and elastic dough from the beginning , before putting our pan in the oven .To obtain that we don´t need to use some strange ingredient or worse some kind of chemical .We have to change just the order of the ingredient , and the way we work the mixture .We can curdle the casein contained in butter with the acidic orange juice .If the pH is lowered to about 5 , the casein micelles lose their negative charge and clump together .This is normally avoided because you pour the orange juice in the mixture after the flour and , principally , the eggs : they have a quite basic pH (the moment the egg leaves the hen it begin to change his pH : the yolk jumps from 6 to 6,6 and the white from 7,7 to 9 or sometimes above ) .But now I think is enough for the chemistry .

Ingredients :
1 1/2 cup sugar
200 g butter
juice of 1 big orange
grated peel of 1 orange
4 eggs
3 cups flour
50 g dark chocolate in chips
2 tea spoon baking powder
rosemary

Preparation : Put in a large bowl the butter keeped at ambient temperature and the sugar .Blend it very well since you obtain a foamy mix .Then pour the orange juice and work it well with a whisk .Now you have a curdled mixture .Than pour in this order , blending with a spoon : the eggs ( one per time ) , the flour , rosemary ( I think rosemary-orange is a perfect combination of flavour and taste) , chocolate and finally the baking powder .You may need trained muscles to bland this dough ( don´t use the hands , it is very sticky ) .Now we have to wet the mixture with a small amount of milk ( 1/2 glass or less ) to start the reaction of the baking powder ( if the dough is too dry , perhaps the acidic and the basic compound will have problem to encounter ) . Now pour the dough in a basted pan and cook it at 170 °C for about 1h 10 min .In the first 1/2 h you may put a small pan with hot water in the oven to avoid the premature formation of the crust .Than you have to take it off .
I can ensure you that this cake will shoot up pretty good .( and also has a very good taste )