It’s not a scientific study, but since I’ve been preparing orange peel for eating (about 2 years), I haven’t had any sore throats or colds. The peel is more nutritious than the fruit, but I enjoy the orange, too. I haven’t been able to find any information on how cooking the peel degrades the nutritional value. On the other hand, I assume any testing was done on cooked peel. Using the peel of one orange (in sections) I heat it in a cup in the microwave, change the water, and repeat about 3 times. I cut each section into small strips. Then I soak it over night in sugar water, drain, and sprinkle with sugar and refrigerate. It’s not like orange peel candy, much softer and still slightly bitter. However, I don’t eat much at one time. Maybe one small strip a day.