Table 1. Protein quality rankings. Protein Type Protein Efficiency Ratio Biological Value Net Protein Utilization Protein Digestibility Corrected Amino Acid Score Beef 2.9 80 73 0.92 Black Beans 0 0 0.75 Casein 2.5 77 76 1.00 Egg 3.9 100 94 1.00 Milk 2.5 91 82 1.00 Peanuts 1.8 0.52 Soy protein 2.2 74 61 1.00 Wheat gluten 0.8 64 67 0.25 Whey protein 3.2 104 92 1.00 Adapted from: U.S Dairy Export Council, Reference Manual for U.S. Whey Products 2nd Edition, 1999 and Sarwar, .