This article was published in the June 2019 issue of Pet Food Processing. Read it and other articles from this issue in our June digital edition.

Pet food processors are responsible for formulating product that provides complete and balanced nutrition. They must approach formulation with a thorough knowledge of nutrient requirements, nutrient concentrations in dietary ingredients, and an understanding of the bioavailability of those nutrients. Chelation and encapsulation are two separate techniques for delivering nutrients in pet food formulations that help processors meet nutritional requirements.



A mineral is a naturally occurring inorganic compound. Minerals are critical building blocks that make up muscles, tissues and bone and benefit hormones, oxygen transport and enzyme systems. Plants and animals do not produce minerals, but minerals can be absorbed by plants. Chelated minerals can be used to provide the mineral nutritional needs or requirements in a complete pet food.

Chelated minerals are a chemical reaction between a mineral and an organic molecule called a ligand. In this reaction, the mineral bonds to the ligand in two sites that results in a chemical ring structure of various atoms called a heterocyclic ring. The bonds are typically coordinate covalent on one of the attachment points. In pet food formulations, the ligands are typically amino acids derived from the chemical synthesis or hydrolysis of proteins.

Chelated minerals are more effectively absorbed by animals, which can result in physical health benefits such as mobility and clear eyes.
“Imagine chelation as a basketball held with both hands,” says Dana Tomlinson, Ph.D., global species leader-specialty, Zinpro Performance Minerals, Eden Prairie, Minnesota. “The mineral is ‘held’ in place by an amino acid with the carboxyl and amino groups on its end serving as the hands to hold a metal. This creates a tight, chemically stable bond.”

Most of the nutritionally relevant minerals are offered as chelates. This includes zinc, copper, iron and manganese. Magnesium, selenium and calcium can also be chelated, but sodium and potassium cannot. If a chelate is properly formed, the mineral is bonded to the ligand and limits interaction with other nutrients which allows the mineral to remain bioavailable. Inorganic mineral sources can be ineffective because they don’t have those limits, according to Stephen Ashmead, research fellow, minerals, Balchem Corp., New Hampton, New York.

Minerals made organically are more closely aligned with the needs of the body. Tomlinson explains that in this instance organic has a different meaning than organic in the food industry. Organic minerals are complexed, or bound, with amino acids and minerals. Inorganic minerals are rocks mined or taken out of the soil and used in feeds and chemistry. Generally, chelated or organic minerals pose lower risks of toxicity or illness due to poisoning compared to inorganic metal supplements, which are more likely to create imbalances and predispose an animal to toxicosis because it is absorbed by a completely different mechanism, he adds.

One of the most common reasons to use chelation is to make the mineral more bioavailable to the animal. Bioavailability enhances absorption in the gastrointestinal (GI) track and in other organs in the body. A fraction of the dose is absorbed, escaping first-pass elimination. Trace minerals, or micronutrients, play an essential role in many metabolic functions. Micronutrients benefit an animal’s growth and development, skin and coat quality, reproductive performance, energy, metabolism, paw pad integrity and overall health.

“Besides delivering highly bioavailable mineral nutrition, the chelation provides some protection,” Ashmead says. “This means that there can be less interaction with naturally occurring substances in the food that would diminish the bioavailability. Since the mineral is bonded to the ligand in the chelate, unwanted interactions with other ingredients are diminished and provide for a more nutrient-dense food.”

"Since the mineral is bonded to the ligand in the chelate, unwanted interactions with other ingredients are diminished and provide for a more nutrient-dense food,” says Stephen Ashmead, Balchem Corp.

The choice of an inorganic form of a mineral over a more bioavailable chelated form results in less availability for the animal to use the mineral. To compensate, a processor must use a larger amount of the inorganic material, creating the possibility of imbalance. The excess mineral can accumulate in the organs, which affects the ability of the animal’s body to produce energy.

While some consumers, particularly those who make their own pet foods, have concerns about the use of chelated minerals, Tomlinson offers assurance that companies such as Zinpro, a global manufacturer of organic trace minerals in a 1:1 ratio (1 amino acid: 1 metal), have done the research and have the peer-reviewed information to support their recommendations. Zinpro metal amino acid complexes are stable through extrusion and can be an excellent source of trace minerals for pet foods.

Tomlinson points out that depending on the source, extrusion can damage vitamins by up to 50% and an additional 10% to 20% can be lost in the drying process. Once the food sits on the shelf at the warehouse or store, it can lose another 20% to 45%.

Successful formulation of pet food and treats demands understanding the functionality of the minerals supported by the necessary background and research. Marcie Campion, Ph.D., nutritionist and pet technical lead, Cargill, Wayzata, Minnesota, says important discoveries for pets can sometimes originate from the human side of technology, as in the case of omega-3 supplementation. Findings can also move from pets to humans, as in the case of DHA supplementation. Scientists knew that DHA made puppies smarter. Years later, DHA became relevant for humans because of the benefits it offers in the brain development of children.

Proper absorption of chelated minerals can stimulate mechanisms to perform better in the animal. Campion cited a study using a zinc complex to prevent cloudiness in the eyes of chickens. Attributes such as clearer eyes and improved mobility are outward indicators to a pet owner that an animal is healthy. Seeing the benefit of supplementation in this instance, Campion questioned if such a study could also benefit dogs.

“At Cargill, we have the benefit of having cross-pollinating research conversations about what’s happening with livestock and with pets,” Campion says. “These conversations help trigger ideas on how we can make the lives of pets better.”

Similar conversations are also a starting point when creating a new formulation to improve the life and longevity of pets. Often the process differs for each processor. Campion says some processors come in with existing information and know what they can and want to put into a formulation. Others arrive looking for what’s new and unique, and interested in the possibility of making a new claim.

Campion recommends processors always work with a qualified team that includes a nutritionist when creating a new formulation. Knowing too much of a mineral can be toxic to an animal, a nutritionist can articulate the thresholds for toxicity in the premix or the total mineral use. Lastly, she encourages processors to have multiple people review each formula.

"It is important to pet owners that the pet food delivers on the claims it makes, so you can mix and match the mineral sources to get the desired benefits and different pet food makers may take different paths. There are lots of ways to get there,” says Marcie Campion, Ph.D., Cargill.

When it comes to choosing chelated or nonchelated minerals in a formulation, cost is a consideration. In many instances, however, chelated ingredietns can be  much more cost-effective than expected.

“Adding Zinpro zinc, manganese, copper and iron to a dog food product is $8-$10 per ton,” Tomlinson shares. “For a 20-lb. bag, that’s only 8 to 10 cents of potential cost for the added benefits of skin, coat, foot pads, gut health, immunity and overall better wellbeing.”

For pet owners without a scientific or nutritional background, these additions from processors coupled with outward-facing signs are the best way to determine if they’re providing their pet with food designed to support a healthy life.

“People who make pet food have the best interests of the pet in mind, because most of us have at least one pet,” Campion says. “We help educate our customers how to formulate complete and balanced pet foods to help provide the best quality of life for their pets. It is important to pet owners that the pet food delivers on the claims it makes, so you can mix and match the mineral sources to get the desired benefits and different pet food makers may take different paths. There are lots of ways to get there.”



Bitter or off-flavors can make consuming healthy foods and ingredients challenging for animals and humans alike. Thankfully, encapsulation technology developed 30 years ago continues to allow processors to sidestep these issues with an element of protection. Encapsulation safeguards a core material against harmful influences such as light, oxygen and humidity during shelf life, and in part, during processing.

Encapsulated mineral diagramTo revisit Tomlinson’s earlier analogy, encapsulation features a ‘ball’ or element that’s covered in mud or paint. The process improves handling and can protect from moisture, heat or other extreme conditions, enhancing stability and maintaining viability.

Encapsulation is predominately limited by the starting material’s state (solid preferred), particle size and particle size distribution, and reactivity. Sugars, proteins, gums, natural and modified polysaccharides, synthetic polymers and fats can be used to protect the core material.

“Using encapsulation, processors can mask taste and off-flavors, overcome pre-reactions and interactions, stabilize nutrients, improve texture and deliver beneficial nutrients up and down the gastrointestinal tract of humans and animals,” says Winston Samuels, Ph.D., founder, president and chief executive officer, Maxx Performance, Roanoke, Virginia.

Balchem’s PetShure portfolio has encapsulated sodium bicarbonate to provide better control of the leavening reaction in a variety of products to modify density, increase porosity, and otherwise manipulate piece size and structure. Encapsulated acids help control pH and the stability of finished products without impacting raw material freshness and handling. Its structure and forming materials can delay and reinforce various protein mixtures’ textures and add formula or processing options. Balchem Corp. has experience in a variety of raw materials from sugar, salt and various organic acids to vitamins and minerals.

Encapsulation technology can also stabilize probiotics for use in pet food processing and help manufacturers deliver on guaranteed colony forming units (CFUs) per gram to improve gut health. CFUs help estimate the number of viable bacteria or fungal cells in a sample. As the food or treat moves down the GI tract toward the small intestine, the encapsulated coating breaks down to make the active ingredient available to the animal.

“In today’s environment where consumers want the best clean label ingredients for their pets, encapsulation technology represents a more viable alternative instead of using expensive preservatives and flavors,” Samuels says. “Encapsulation as a delivery system allows formulators to increase the bioavailability of nutrients through use of its food-grade vegan coatings. Aside from the active, only the vegan coating is added. Also, the technology protects labile (susceptible to alteration or destruction) compounds such as enzymes, probiotics, prebiotics and others, which typically would be destroyed during processing.”

Pet food can deliver probiotics through encapsulation, which protects the nutrient until it enters the gastrointestinal tract where it dissolves and becomes active.
Cost is also a consideration when choosing between encapsulated and non-encapsulated ingredients. Instead of cost, Samuels recommends processors think in the context of increasing bioavailability of nutrients, masking taste and off-odors, and increasing stability and shelf life without using flavors, additives and preservatives. The use of additives is often more expensive and can limit mass incorporation. With the help of encapsulation, processors can add a high volume of active ingredients to pet treats with far fewer additives and flavors to achieve acceptance.

In support, Samuels gives the example of soy isoflavones, which are shown to be beneficial to spayed and neutered dogs. Because dogs don’t like the taste of soy isoflavones, expensive flavors and additives are used to mask the taste, quadrupling the cost. The solution? Microencapsulation, the complete coating of individual particles of a product, commonly in the range of 10 to 100 micron. Microencapsulation incorporates ingredients, enzymes, cells or other materials into small capsules for delivery at the appropriate time by preventing the reactive materials from interacting with other ingredients.

“With all encapsulates, the benefit of usage is either the protection of a raw material from processing conditions or optimal performance or the ability to use a reactive raw material to improve a product’s characteristics without impacting the established process or make-up,” concludes Robert Mason, senior applications scientist, applications research and development division, Balchem Corp.

Depending on each processor’s unique needs, chelation or encapsulation can be viable methods to protect a processor’s investment, prevent unnecessary over-formulation and work toward a greater goal of improving and extending the lives of pets.

Read more about product development, ingredients and formulation.