Today, a question
Recently, I have been doing more baking, cakes and pastries, macarons. This frequently involves whipping egg whites, beating or mixing in icing sugar, and making meringue. Icing sugar (powdered sugar in the US) contains about 2-3% corn starch as an anti-caking agent. I was aware of this but had never thought much about it. However, reading about the optimal beating of egg whites in various of my cookbooks (I have a collection of over 300), I wondered if the corn starch in the icing sugar had a detrimental effect, a positive effect, or was of no consequence to the properties of the beaten egg whites. If detrimental, for recipes calling for Icing sugar, I could always take fine castor sugar and make my own icing sugar by putting it into a very high-speed mixer/blender. I couldn't find an answer to this. I am sure that you will know.
Additionally, when making meringue, are there any additives, emulsifiers, etc. that would improve the end result? The firm Sosa has many specialty products, mainly used in professional kitchens.