This recipe came from Extending the Table, and I didn’t have to substitute anything. Well, ok, I did use GF flour, but anymore that doesn’t count. The filling is a nicely spiced, thickened pineapple sauce, which was light and tropical the perfect foil for these cold, damp spring days we’ve been having.
I learned a little something about rice flour as I made this pie. I used the Gluten Free Pantry’s pie crust, and I was not impressed. It was crumbly and didn’t hold together, which is why the top looks the way it does. It tastes great though.
I’m starting to wonder if my consistent problem with items made with rice flour is because we are egg-free? Perhaps the flax and xanthum gum aren’t enough with rice flour to make it come together and stay together. Which reminds me, there was no xanthum gum in this pie dough mix and I didn’t add any. Hmm…. Well let’s see how they compare:
Rice flour is very low in protein, and flax seeds, while higher in protein, have less than an egg. When I make something based in rice flour, it will only have the 3.5 to 5 grams of protein depending on how much flax I use. Rice flour mixes that use eggs, have 8 grams of protein. That’s only 1 gram shy of the protein content of wheat flour and an egg.
When using regular wheat flour, the amount of protein is related to how much gluten will be produced. The higher the protein content, the more gluten will be produced. But, what about gluten-free proteins? Are they as important to baking? Colorado State’s Extension office has some useful information on the subject. They point out that gluten is important in baking because it lends structure and creates spaces where gas can form, but not escape, which makes baked goods light, fluffy, and chewy. Without gluten, air bubbles can escape, which is why we use eggs, xanthum gum, and other binders. They make up for some of that lost elasticity.
Given that explanation, I think my hunch is right- those of us who are egg-free are going to have a harder time with rice flours. Now to ponder the next question, will all proteins create those ideal situations to keep air and moisture in the baked good, or will only some proteins? If all proteins, then let’s just experiment until we get the protein ratios right and call it a day on all this flour experimentation. If all proteins are not created equal, then which ones are more suited to baking? I mean, if all we needed to do is add in another high protein flour and all our gluten-free worries are over, then why did anyone even bother experimenting with rice flour? And, finally, where does xanthum gum fit in here? It doesn’t have any protein at all! Is there a food scientist in the audience?
Look for the thrilling answers to these and other wheat-free questions in future episodes!