This article was published in the September 2019 issue of Pet Food Processing. Read it and other articles from this issue in our September digital edition.
Chickpeas, lentils, dried beans and peas – these ingredients are collectively known as pulses. They are invading the human food and beverage space, so it should be no surprise that their presence in pet food is growing. Many of today’s pet owners are applying human food philosophies to the products they select for their furry companions. This includes the consumption of more plant-based foods such as pulses.
“Pet food trends closely follow human food trends, so with the increased focus on sustainable eating, gluten-free diets and plant-based protein, pulses have become a popular ingredient for pet food,” says Jennifer Adolphe, nutrition manager, Petcurean, Chilliwack, British Columbia, Canada. “There are a variety of pulses that can be used in pet foods. As a nutrient-dense food source that is locally grown in Canada and the US, dried yellow and green field peas in particular are appealing to health- and environmentally-conscious consumers.”
A mixed bag
The use of pulses in pet food is driven by their multi-functionality, accessibility and cost efficiency, according to Christopher Marinangeli, director of research, scientific and regulatory affairs, Pulse Canada, Winnipeg, Manitoba, Canada. Dried peas are the most utilized pulse in pet food, followed by chickpeas, lentils and all other pet food-approved dried beans.
Peas are low cost and widely available, he says. Chickpeas can carry a higher cost and have a higher oil content compared to peas. Lentils can also cost more than peas. But in general, all pulses are rich in protein and fiber.
“Today’s widespread use of pulses in pet foods can be traced back to the 1990s, when some manufacturers were seeking ways to differentiate their brands and products by launching grain-free products containing alternative sources of carbohydrates and proteins,” says Dr. Gary Davenport, companion animal technical manager, Archer Daniels Midland Company (ADM), Chicago, Illinois. “Pulses were a natural fit for these new foods due to their carbohydrate and protein composition. The current proliferation of grain-free products reflects the continued consumer demand for these products.”
At one point in time, pulses were considered fillers. They were economic replacements for meat and poultry, as they maintained a desirable nutrition profile while reducing costs associated with animal protein. Today, pulses are recognized as sustainable crops that provide a desirable balance of macro- and micro-nutrients.
Pet food formulators need to be aware that not all pulses are created equal. Some contribute compounds that may or may not agree with dogs and cats at different life stages. Other considerations include issues with limiting amino acids and anti-nutrients. And, with the recent rise in grain-free diets, the potential connection to canine heart disease.
While most dogs are able to exist on properly balanced meatless diets, cats are obligate carnivores. They require meat products in their diet due to their taurine requirement and inability to convert carotene to retinol. This means a vegetarian diet does not supply enough vitamin A to cats. Pulses may be part of their diet, but not their sole source of amino acids. That makes pulses much more common in dog foods than cat foods.
“Pulses, like all ingredients, have a unique nutrient composition. These unique nutritional differences should be taken into account when formulating nutritionally complete pet foods to ensure the selection of complementary ingredients to meet all the nutrient requirements of the dog or cat,” says Dr. Gary Davenport, Archer Daniels Midland Company.
“Cats also have a simpler, shorter digestive tract with limited fermentative capacity for plant-based ingredients,” says Gary Davenport, companion animal technical manager, ADM Animal Nutrition, a division of Archer Daniels Midland Company (ADM), Chicago. “While cats do have some ability to use plant-based ingredients, the long-term feeding of a strict vegan food is not biologically appropriate for cats due to their specific nutritional needs. Vegan cat owners should not mimic their personal dietary choices when selecting a cat food if they are concerned with the long-term health and wellness of their feline companion.”
Patrick Luchsinger, manager, marketing and business development, pet food, Ingredion Inc., Westchester, Illinois, says, “Plant material is more difficult [than animal protein] to break down, so conversely herbivores have much longer intestines. Dogs, on the other hand, have an intestinal length just slightly longer than the cat.”
Davenport agrees, saying, “Pulses, like all ingredients, have a unique nutrient composition. These unique nutritional differences should be taken into account when formulating nutritionally complete pet foods to ensure the selection of complementary ingredients to meet all the nutrient requirements of the dog or cat.”
That does not mean more plant-based ingredients cannot be included in a cat’s diet, especially if the food is properly fortified. Plant-based proteins may be used in combination with animal proteins to achieve a highly palatable, high-protein food or treat for both cats and dogs.
“Pulses have a 50-plus year history in the pet food world, helping to provide many pets with a healthy and well-balanced diet when included in properly formulated food,” says Tim McGreevy, chief executive officer, American Pulse Association, Moscow, Idaho. “The addition of pulses to pet foods has added a plant-based source of nutrition that is packed with protein, fiber, vitamins and minerals. To top it off, they are a sustainable crop, which makes them better for the planet.”
“In general, pulses are versatile and serve as a flavor sponge, so they comfortably fit into formulations across the spectrum,” he adds. “They serve as a perfect solution for a plant-based protein source in vegetarian or vegan diets, but also create a perfect pairing with animal-based proteins in formulations and are successfully integrated into both. No matter the diet or flavor profile, pulses boost nutrition, fiber and sustainability of the final product.”
Something that must be considered when formulating pulses into pet foods is the presence of anti-nutrients, which are natural compounds produced by plants to protect their seeds from animal consumption. They earned the name anti-nutrient because they can interfere with absorption of nutrients needed for an animal — including humans — to maintain optimal health.
Most anti-nutrients are present in the hull, skin or coat of plant seeds. There are different types of anti-nutrients that can disrupt the digestion and absorption of different nutrients. Phytates, for example, are compounds that bind minerals, preventing their absorption by the body. Carnivores cannot break down phytates because they lack the enzyme phytase. Other anti-nutrients present in pulses include tannins, as well as protease, lipase and amylase inhibitors, the latter being compounds that prevent enzymes from respectively breaking down proteins, fats and carbohydrates for proper digestion and nutrient absorption.
The good news is that “anti-nutritional factors in pulses are largely addressed with cooking and processing, such as extrusion,” Marinangeli says.
Focusing on protein
The rise in grain-free diets places the focus on protein. Therefore, protein quality must be considered. This includes protein content, amino acid composition and protein digestibility.
“In each of the pulse crops there are varying levels of the different amino acids,” McGreevy says. “The level of these compounds, as well as other nutrients, in each pet food or treat will really depend on the formulation of the product.”
Luchsinger adds, “Pulses may not be completely utilized for swapping out animal proteins due to pet owner preference to have animal protein sources as the first ingredient listed in the formulation. However, pulses provide an alternative protein source to soy or grain-based proteins, such as wheat.”
Protein requirements, including amino acid profiles, vary by life stage and breed. That’s why many pet foods have historically called out these particulars on their recipes. Pet food is not a one-size fits all business.
“While pea protein contains all the essential amino acids, it is not considered a complete protein because two of the amino acids, methionine and cysteine, are limiting,” explains Melissa Machen, Cargill Texturizing Solutions.
“The only life stage in which pulses should be limited is puppy and kitten foods due to the immature nature of their developing digestive tract,” Davenport says. “Puppies and kittens do not have the ability to utilize fibrous material and should be fed foods with more easily digested ingredients like rice and animal protein.”
Davenport points out that when formulating with pulses, it’s important to see those ingredients in terms of their respective nutrient contents — such as amino acid levels — in order to achieve total nutritional efficacy for a dog or cat food.
“As with humans, pets need protein sources that are complete proteins, meaning they contain the required levels of all essential amino acids,” says Melissa Machen, senior technical services specialist, Cargill Texturizing Solutions, Minneapolis. “Amino acids are important for organ and muscle health of the animal, along with many other growth functions.”
“Pea protein is gaining popularity in pet foods and treats,” Machen says. “While pea protein contains all the essential amino acids, it is not considered a complete protein because two of the amino acids, methionine and cysteine, are limiting. However, formulators can blend pea protein with a complementary protein source, such as rice, chickpea, soy or pumpkin. Rice is a common option as it has higher levels of methionine and cysteine to complement the pea protein.”
Like many grains, pulses are a source of carbohydrates, which are necessary in product formulating. The added bonus is they are a much more concentrated source of protein and, in many instances, fiber as well. “Pulses contribute fiber and resistant starch, which provide benefits for the digestive system,” Adolphe says. “Peas also contain compounds known for their antioxidant properties, which may protect against various diseases, such as cancer.”
This makes them powerhouse ingredients in the eyes of a formulator. Varied formats are available, such as whole, ground and starch. This assists with developing targeted textures, such as crunchy, chewy or even stew-like for wet applications. “When producing pet food through extrusion, carbohydrates are one of the most important functional ingredients needed to give kibble its shape, texture and density,” Adolphe says. “They have excellent binding and expanding capacity to hold kibble together and create its desired texture. Without the use of carbohydrates, it is very difficult to produce a well-formed kibble.”
Pulses also provide simple, understandable ingredient declarations and may function similarly to more highly processed ingredients, including animal by-products and modified binders. “Beyond nutrients, amino acids and protein, pulses also deliver certain functionalities that benefit the shape, reduce breakage, and improve the chewiness or firmness of the end product,” Luchsinger explains. “It is notable to mention that ingredients aren’t as effective if they’re not blended with other ingredients that make the meal as nutritious and digestible as possible.
“The future of pulses in the pet food industry is bright as pulses bring many nutritional benefits such as protein enrichment and amino acid content,” Luchsinger says. “Many pet food and treat manufacturers are looking to fortify their products with protein and replace corn, soy and wheat with novel flours to differentiate their products with label claims like non-GMO, gluten-free, made in the USA and sustainably sourced.”
“They provide functional benefits such as thickening, gelling, fat binding and helping to keep a consistent and uniform structure and shape in the application,” he concludes. “Pet food formulators realize that a larger variety of ingredients in the pet food formulation will provide more for the animal than a very limited formulation and pulse ingredients can help provide ingredient options for them.”
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