Weighing up the advantages of utilizing lentil pasta byproduct in pet food

Food demand will rise greatly during the coming years, challenging the quality of life of both people and their pets.

Recent research has found that the presence of lentil byproducts in pet food may both promote intestinal health and act as prebiotics in dogs, while also being environmentally sound.

Planet, people and profit

It is undeniable nowadays that the world is changing from a climatic and demographic point of view.

Alternative raw materials in pet food, such as byproducts from the human food industry, can increase the provision and digestibility of different nutrients while at the same time offering enhanced economic and environmental sustainability.

A nutritional approach is considered sustainable if it is in accordance with the ‘3 P’ dimensions: planet, people and profit. These changes, alongside the increased food quality awareness of pet owners, are leading pet food manufacturers to introduce products with new sources of non-structural carbohydrates (NSC) and proteins.

Recently, legumes have been rediscovered by the pet food industry as new or alternative sources of both carbohydrates and proteins. The marketing focus on these ingredients has been promoted by manufacturers to create an option with greater appeal than more traditional components of pet food diets, such as cereals.

In fact, grain-free diets – based on legumes and tubers as main carbohydrate sources – are already largely present in the pet food market.

The production of lentil pasta in Italy has been increasing steadily due to the rise of celiac disease in humans; as a result, the byproduct of this human food (discarded due to discoloration or shape) has grown in quantity and has received the attention of the pet food industry as a possible alternative ingredient for dog food.

Lentil pasta byproducts as pet nutrition

In our recent study, published in Frontiers in 2024, lentil pasta byproduct (LP) was evaluated for both the implications involving the extrusion process as well as digestibility, palatability and physiological parameters in dogs.

The digestibility parameters of dry complete food based on LP showed that this ingredient retains high bioavailability of nutrients. In addition, lentils can positively influence the post-prandial glycemic and insulinemic response, lowering the curve peaks compared to rice, possibly affecting the metabolic pathways of the animal.

Nonetheless, the palatability of the ration seemed to be enhanced by the addition of LP, of which its organoleptic properties appeared to be appreciated by dogs more than in the case of rice.

However, extrusion processing parameters need to be carefully evaluated due to the reduced level of starch and increased level of fiber and protein of legume based diets compared with cereal-based ones.

In fact, the resistance to mass flow can affect kibble formation and hardness, altering the final product characteristics.

Effects of high fiber content

The research also examined how well dogs digest nutrients when their diet includes either rice or LP. The study found that when rice was only partially replaced with LP, the digestibility of dry matter, organic matter and crude protein improved.

However, when rice was completely replaced with LP, nutrient digestibility decreased. Similar results were observed in other studies using legumes such as peas, chickpeas and fava beans, showing better digestion with partial substitution compared with full replacement.

This decline in digestibility may be due to the higher fiber content in legumes, which can affect how well dogs absorb nutrients. Despite this, the inclusion of LP in dog food, especially in moderate amounts, was found to be appropriate and potentially beneficial as part of a balanced diet.

Bacteria in dog’s large intestine help break down dietary fiber through fermentation. This process produces substances including short-chain fatty acids (SCFAs), such as acetate, propionate and butyrate, which support gut health.

In this study, adding higher amounts of LP to dog food increased fiber intake, which led to greater fermentation and higher levels of these beneficial acids in the feces. Importantly, LP could offer a more affordable alternative to common prebiotic supplements like FOS (fructo-oligosaccharides) and inulin.

Facing future food challenges

The potentially increasing burden associated with feeding pets needs to be recognized as part of future food system challenges in the light of the magnitude of the food waste crisis.

For this reason, the revalorization of food byproduct should be prioritized. In particular, the concept of upcycling, i.e. using still nutritionally valuable but discarded byproducts, has stirred research interests in various fields, including marketing, even though the concept is already quite established in the pet food industry.

Opposing this idea is the so-called ‘premiumization’ trend in pet food, i.e. the use of higher cost ingredients which, in certain cases, are directly taken from what would be considered suitable for human consumption.

The current role of researchers, as well as pet food manufacturers, focuses on mitigation options to increase sustainability while enhancing economic growth with appropriate marketing.

A current trend to achieve an improved sustainable use of agriculture while increasing planetary health is to facilitate the adoption of human plant-based diets. From an environmental standpoint, plant-based diets require lower energy, land and water usage compared with meat-based diets.

When combined with meat based ingredients, plant proteins can overcome their deficiencies and form part of dogs’ diet – although for cats this can be a greater challenge due to their carnivorous nature.

The main opportunity to increase the sustainability of our pets’ diets is to increase knowledge about new ingredients and correctly target consumer choices through scientific evidence to ensure pet food safety.