The Preparedness Advice Blog linked to this online manual that deals in depth with the manufacture of pemmican. Pemmican, properly prepared, can keep for years without refrigeration and ounce for ounce beats most other stored foods for providing energy for hard work. Pemmican is either 50% rendered fat and 50% powdered, dried lean meat or in some recipes dried fruits are added. As long as it’s 50% rendered fat and at least 45% lean meat you’re good to go so adding in some fruit is fine.
Though the manual has detailed instructions on the process including rendering fat Dave Canterbury has a great instructional video of rendering deer fat in tallow in a primitive situation that is equally useful and includes some other uses for the rendered fat: