There are lots of color sample tools online, such as:
Perhaps take a photo of a color you like, save it to your computer, and then use a tool like Photoshop to crab the color value(s) in that image as your starting point.
What you could do is to find a good sized picture of a golden brown loaf and use the colours and texture from that in your illustration.
I dont think you will easily represent a good looking loaf in a solid colour of brown tbh.