In AMERICAN GARDENING MAGAZINE, it tells you to use the rind of an orange, lemon or grapefruit for your garden. First, dry the rind out. Then cut it up small, put it through a coffee grinder till it is powder. This is the best phosphorus and potassium nutrient your garden will ever need. Then add gelatin for your nitrogen. Have you ever heard of this before? It seems they have done experiments on this. Thought I should ask.
Citrus Peels are used in organic fertilizers. I did not find any research in the addition of gelatin to your mixture.
Your Citrus can be composted also.
Here are a few articles for you.