Evaluation of plant-based recipes meeting nutritional requirements for dog food: The effect of fractionation and ingredient constraints

Nowadays, plant-based human food products are considered to be more sustainable than animal-derived products. This could also be true for pet food, explaining a potential demand for plant-based pet food. Here, the concept of the degree of crop protein utilization was introduced for complete plant-based foods for dogs to understand the balance between nutrition and sustainability. The first step was to investigate which level of refinement, i.e. fractionation, of plant protein sources was necessary to fulfil the FEDIAF recommended nutrient levels for adult dogs. Moreover, the consequences of excluding certain ingredients were investigated. Thus, a database of plant-based ingredients, including the fractions of flours, protein concentrates and protein isolates, was created. Linear programming was used to formulate nutritionally complete recipes, minimizing either the number or the amount of nutrients that need to be added. Constraints of certain ingredients were translated to exclusion of soy, gluten, and/or tomato and potato. The recipe with the highest degree of crop protein utilization was the recipe in which isolates, concentrates, soy, gluten, tomato, and potato were excluded. The outcome of the optimization calculations showed that the level of refinement of ingredients, i.e. fractionation, has a direct influence on the sustainability of a recipe. Further, it was possible to obtain efficient recipes without the use of heavily processed ingredients and excluding certain undesired ingredients, while fulfilling the nutrient requirements of foods for adult dogs. Fortification to account for missing nutrients remained in line with the fortification used in conventional animal-based pet food. Thus, the design of plant-based dog food that is complete, in the most sustainable way, is achieved with recipes formulated with minimally refined ingredients. The results further show that the concept of calculating the degree of crop protein utilization when formulating recipes provides valuable information on which combination of raw materials to use.