By most measures, consumer interest in plant-based diets, and by extension in plant proteins, is booming. The benefits of long-established protein ingredients are fine-tuned and generally well understood. Emerging plant proteins are now finding their own spot in the marketplace.
Evidence of plant protein popularity is found in consumer research to industry trends. For example, one of Kroger's top seven 2021 food predictions was Ketotarian Foods. “Enter the 'ketotarian' diet: a plant-based spin on traditional keto guidelines."
A second Kroger prediction was Mushroom Mania. “Consumers should expect to see mushrooms play a starring role in a variety of new products in 2021, including blended plant-based proteins…” Similarly, Whole Foods’ list of "The Next Big Things: Top 10 Food Trends for 2021" included “The Mighty Chickpea" and "Fruit and Veggie Jerky."
U.S.-based food processors creatively employ plant-based protein ingredients and whole food components in their products. Laird Superfood’s Renew Plant Based Protein, positioned as a supplement, adds the somewhat exotic sacha inchi and cranberry proteins to hemp and pumpkin proteins.
Sweet Earths’ Bean and Mango Cuban bowl combines black beans and quinoa, a whole food legume and “pseudocereal” respectively. And, the Kind Protein Bar contains customer-pleasing whole food sources of protein ― peanuts and almonds ― then gives the product a protein bump with soy protein isolate.
Many predict a bright future for plant-based protein ingredients. It is a safe prophecy. In a recent webinar by Geneva, Switzerland-based Giract, the ingredient market research and strategy firm noted that with about a 70% share, plant proteins have long dominated the protein ingredient marketplace with their predominant use in the food and feed industry.
Soy and wheat protein ingredients compose nearly two-thirds and nearly one-third respectively of this global ingredient category. Pea proteins, although currently a small fraction in comparison, have been growing in importance. Behind these three is a large field of emerging plant proteins looking to carve out a niche for themselves in the hearts of consumers and a place in product formulations.
Plant Protein Content and Regulations
Regulations are a tremendous driving force for changes in the food industry. Novel ingredients that will be formulated into U.S. products must progress past certain hurdles such as achieving GRAS status (e.g., self-affirmed, FDA notified), says Lauren Swann, president/CEO of Concept Nutrition. However, common industry practice and existing government standards also guide expectations and how ingredients are marketed.
For example, soy flour, concentrates and isolates are clearly defined by Codex with ranges of “More than or equal to 50% to less than 65%,” “More than or equal to 65% to less than 90%,” and “More than or equal to 90%” respectively.
Codex also has a “General Standard for Vegetable Protein Products (CXS 174-1989 Amended in 2019),” says Scott Grare, senior manager of regulatory affairs for Ingredion Inc.
When it comes to the expected protein content of commercially available ingredients, a product developer should start with specifications offered by the vendor.
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A “short list” of just some of the commercially available ingredients containing 30% or more protein include those from the nut family such as almond, cashew and walnut proteins. Seed and grain sources include sunflower, chia seed, oats, golden flax, barley and hemp. Some of these ingredients as well as pumpkin, pea and brown rice can be found with 80+% protein. Chickpea, a pulse, has joined canola/rapeseed, soy, potato and wheat among others as being commercially available at some 90% protein purity.
Plant flours also can increase a product’s protein content as well as contribute other functional and nutritional components.
An Ingredient Focus: Enhancing Protein Properties
If plant proteins are to achieve their full potential in human food applications, product formulators require more from them than satisfactory taste and the ability to be mixed into powdered drinks and health bars.
A plethora of dairy, soy and wheat protein ingredients with fine-tuned attributes have been developed for a wide range of applications. The race is now on to similarly improve and better understand the flavor, nutrition and functionality of emerging plant proteins. See the October 2020 article Alternative Proteins: The Problems and the Promise.
Flavor challenges are not uncommon with newer plant protein sources. Both suppliers and formulators have a role in meeting this challenge. “An issue for some formulators is that certain pulse protein products can carry either a pulse flavor or are bitter,” says Clifford Hall, a professor at South Dakota State University.
He notes that some suppliers now offer a line of “deflavored” pulse ingredients. Additionally, formulators can help mitigate the issue through their flavor choice. One approach is the use of savory flavors, which tend to mask/completement pulse flavors, Hall adds.
Protein ingredients also possess a variety of valuable physiochemical properties and activities. Hydration, which is important to a protein’s solubility- and viscosity-enhancing abilities, is crucial in many applications. Solubility depends on the properties of the protein and the solvent (i.e., food phase) into which it is put. Examples of solvent properties include charge of other ions, temperature and concentrations.
Emulsification and foaming are other key protein abilities. As a protein molecule denatures (unfolds), interior hydrophilic groups are exposed. This allows the molecule to have an affinity for both polar (e.g., water) and non-polar phases of food (e.g., oil). The proteins tend to locate at oil-water interfaces, reducing interfacial tension between the two phases, which helps stabilize an emulsion.
Numerous factors impact how well a protein functions as an emulsifier. A protein’s solubility and isoelectric point as well as the surface viscosity at the phase interfaces are just a few.
Gelation and precipitation are also crucial activities in many products. They are the result of interactions between protein molecules. Examples of food gel structures enabled by animal proteins include marshmallows (gelatin), yogurt (casein and whey proteins) and quiche (eggs).
Plant proteins now strive to mimic these gel textures. However, this is a particular challenge in that native plant protein gels are significantly weaker than those formed from equal amounts of animal proteins, advises Laurice Pouvreau, research scientist and expertise leader-plant protein technology at Wageningen Food & Biobased Protein Research Group.
A look at commercially available ingredients from an established protein source, soy, to newer pulse ingredients shows how these functions can be utilized in finished products.
Following soy’s functional footsteps
Part of soy protein’s longtime dominance in formulator tool chests has been the development of a broad range of functional soy protein ingredients. Each can serve roles in specific applications.
For example, soy flour is typically used in baking to improve dough quality and add protein content. “It can also be texturized and sold as textured vegetable protein or TVP,” says Jean Heggie, United Soybean Board soy protein consultant.
Soy protein concentrate is available in either powder or textured formats. Its most common applications include processed meat and poultry products as well as meat alternatives. As a powdered ingredient in meat and poultry applications, it will bind fat and moisture and exhibit strong gelling characteristics.
Heggie went on to explain that textured soy protein concentrate (TSPC) also is a popular option for processed meat and meat alternatives. TSPC is made by extruding soy protein concentrate into various shapes and sizes, resembling meat or poultry fibers, granules or crumbles. These ingredients are available colored, such as for beef, or uncolored; and some are fortified.
In meat applications, TSPC is used to improve economics while maintaining excellent eating quality. “In meat alternatives, they deliver great-tasting meatless or vegan alternatives to beef, chicken, pork and seafood,” she adds.
Due to its high protein content and high protein quality, isolated soy protein (ISP) is a versatile ingredient that can be used to deliver protein nutrition, functionality and affordability in a wide range of applications. Unlike other soy protein ingredients, ISP is likely to be the protein of choice for high-protein, flavor-sensitive applications like nutritional beverages, protein supplements, nutrition bars and dairy-free alternatives, Heggie suggests.
“It can be used as the sole protein source to deliver high-protein, plant protein positioning or in combination with dairy or other protein ingredients to deliver high protein positioning,” offers Heggie. ISP can also be extruded. One of the most popular is a nugget or “crisp” format, which is a popular choice for adding protein nutrition and crispy, crunchy texture to nutrition bars, snacks, and cereals.
Looking at soy protein’s success, companies are finding opportunities in the development of other plant protein sources. There is interest in pulse proteins due to certain functionalities being similar to those of soy, says Hall. For example, pulse proteins can be texturized to make meat analogs.
Pulse flours, concentrates and isolates are also growing in use. Pulse concentrates and flours are minimally processed and deliver balanced nutrition, says Adrianne Speranza, project leader for plant-based proteins at Ingredion. These ingredients are more commonly used in low moisture applications, are label-friendly and have low allergenicity potential when compared to common alternatives. Pulse isolates deliver the highest quantity of protein to help enable "excellent source of protein" front-of-packaging claims, she adds.
Pulse flours (10-20% protein on a dry basis) are excellent alternatives for wheat flour in baked goods, pastas, coatings, and sauces, and can be used for extruded crisps and snacks to deliver differentiated texture, controlled expansion and protein, fiber and micronutrients, Speranza advises.
Pulse concentrates, 55-60% protein (dry basis), also can be used to enhance nutrition in baked goods as well as beverages and confectionary applications. Pulse concentrates can support water holding, emulsification and egg replacement in dairy and meat alternatives, pastas, soups, sauces and dressings.
Pulse isolates, at 80-85% protein (dry basis), primarily are utilized to deliver increased protein content in baked goods, bars, beverages, dairy alternatives and meat analogs. “Isolates have very high-water binding capacity to deliver viscosity and gelation,” she adds.
Heads up to product formulators
One protein ingredient cannot excel in all physiochemical properties, but there are applications for all of them, says Pouvreau.
For example, when developing a meat analogue using extrusion, a protein with low or intermediate solubility can be applied. However, in the formulation of a cheese or yogurt alternative, a plant protein with high solubility but that can also aggregate and form a gel should be chosen, she explains.
Ingredient variability provides another challenge. For some applications, solubility is key. However, solubility will be different for every commercially available protein — not only between types of plant proteins, but even with the same protein plant source, but from different vendors. "This is due in part to their processing,” says Pouvreau. To obtain an isolate, the protein may be precipitated, heated and spray dried. Each step has an impact on solubility and functionality.
As formulators strive to create plant-based alternatives that match the properties of traditional animal-based foods and beverages, the use of blends and adjunct ingredients often provides much help.
Blends of plant or of plant and animal protein ingredients with complementary amino acid profiles are the best bet when striving to efficiently formulate a finished product of high protein nutritional quality, says Henk Hoogenkamp, a world expert in proteins.
Some sports nutrition products use dairy proteins of fast and slow digestibility for the benefit of consumers. “Blending a plant protein with a whey protein isolate often will outperform an individual plant protein source,” says Hoogenkamp. "Such blends also may offer faster and/or prolonged amino acids delivery, digestion and assimilation.” Such combinations also can improve the end product’s flavor and texture.
Blending plant with animal proteins can be synergistic, as the blend becomes more functional, notes Pouvreau. This is one option to improve gel strength.
To help build back textures expected by consumers, hydrocolloids such as gums and starches are also often used, says Nesha Zalesny, technical consultant for IMR International. For example, processed meat alternatives such as sausages have used sodium alginate as casings. Cold cuts benefit from gel-forming kappa-carrageenan for a "good bite."
Xanthan and locust bean gum as well as wheat and corn starches all can increase viscosity and binding. In processed meat alternatives that are consumed hot, choose high viscosity methycellulose that forms strong gels at lower temperatures. Wheat, corn and potato starches will help increase viscosity and binding, Zalesny adds.
As plant protein options grow, innovative new consumer products will be developed. Additionally, they may offer more efficient and interesting use of animal-derived protein ingredients.