I'm trying to formulate a whole wheat lemon-blueberry pancake mix.  I am using hard white wheat flour, lemon juice powder and lemon peel granules for flavor.  I'm wondering if the lemon effects the cooking of the pancakes by reacting with the baking powder.  It seems like the first couple of pancakes are better then subsequent ones, which also turn out darker in color. Any suggestions?

--Mike

You are right.  Acid in the lemon juice powder is reacting with bicarbonate of soda (baking soda) in the baking powder.  A number of things are likely happening.  The bicarbonate is reacting to make carbon dioxide bubbles upon mixing with the other ingredients.  Baking powder is made to react partially when first mixed, and then again when it is heated (see Baking Soda vs. Baking Powder).  If the bicarbonate is consumed in the initial reaction with the lemon juice powder, then little if any is left to react during the heating phase.

Because pancakes are a thin batter that is used over a period of time, the carbon dioxide bubbles from the initial reaction can bubble off the surface.  Chances are that your first batch or two of pancakes are lighter than subsequent ones.

The way around this is to use a combination of both baking powder and baking soda.  Try replacing about one third of the baking powder in your recipe with about half that amount of baking soda.  Because baking soda contains something around four times the amount of bicarbonate of soda as the same volume of baking powder, there should still be some left over to react later, when the pancakes are cooked.

The exact amount that you need to replace, however, is not easy to calculate.  In checking the chemical composition of lemon juice powder, there doesn't seem to be any specific formulation.  Some are made with natural lemon fruit which is dehydrated, others are made with corn syrup, lemon juice and lemon oil, while others may contain  citric acid and lemon flavor.  What that means is the amount of acid in the lemon juice powder will likely vary by brand.  You will need to play around with the formulation until you get something that works well, produces consistent results and tastes right.  One hint is that too much unused bicarbonate of soda will give your pancakes a distinctly soapy flavor.

The reason for the color change is that blueberries contain a pigment from a group of chemicals called anthocyanins which changes color depending on the acidity of the liquid it is in.  They are red in acids, blue in neutral solutions and greeny-yellow in basic solutions.  Again, replacing some of the baking powder with baking soda should help.

One final suggestion is that you may be able to get some of your lemon flavor by using grated lemon zest instead of, or as well as, lemon juice powder.