Nitrogen footprint of protein-free products

The N footprint is an indicator of N loads from individual consumption of food as well as energy.

A bottom-up approach, N-calculator method, calculates the food N footprint using the N content in consumed foods, such that the N footprint of protein-free foods is treated as zero. In this study, we propose a substitution factor, the virtual nitrogen factor for protein-free foods (VNFree), defined as the potential N load per unit weight of consumed food, to explicitly calculate the production N footprint of protein-free foods. Oil palm and its products were chosen for this case study.