"Eat food, not too much, mostly plants." In a presentation to the Centers for Disease Control in 2009, the influential food writer Michael Pollan followed those seven words of advice with “7 Rules for Eating.” Rule No. 2, “Don’t eat anything with more than five ingredients or ingredients you can't pronounce,” is a key guideline in the popular clean label movement.
As often happens with rules, unintended consequences occur. Efforts to limit the number of ingredients in a formulated product along with a move to plant-based food can impact protein quality. This can also make it more difficult to promote a food’s protein content on labels. However, with thoughtful effort, nutritious products using plant proteins that also meet label regulations can be achieved.
Consumers are interested in plant-based foods, and it influences their diets. According to International Food Information Council (IFIC) Foundation’s 2019 Food and Health Survey, 24% of the 1,012 U.S. consumers surveyed say they "eat much/somewhat more plant-based protein now versus 12 months ago." Some 12% report the same for animal protein. Additionally, over 70% perceive "protein from plant sources" as healthful. Only fiber and whole grains were rated healthful by a greater percent of respondents.
Unmet regulatory requirements
With consumers’ positive attitudes toward plant proteins—and proteins in general—food and beverage companies have been quick to promote their presence on labels. In a July 2018 press release, Innova Market Insights reported that plant-based product claims increased by 62% globally (2013-2017) and that the growth occurred on various platforms including plant proteins.
In the U.S., a protein content claim on a product’s label triggers additional and sometimes ignored regulations.
“It is clear that for nutrient content claims, such as ‘Excellent Source of Protein,’ the Percent Daily Value (%DV) for protein must be declared in the Nutrition Facts box (based on Protein Digestibility-Corrected Amino Acid Score [PDCAAS] tests),” says Leslie Krasny, a former senior counsel with law firm Keller and Heckman LLP. “However, a number of FDA Warning Letters have stated that claims regarding just the grams of protein in a product constitute a labeling violation unless the %DV for protein is declared (again, based on PDCAAS tests).
Calculating PDCAAS for New Products
How to calculate a PDCAAS value for a new product made from ingredients with known PDCAAS values?
“The essential amino acids of each ingredient are summed together in proportion to the amount at which each ingredient is used in the product formulation,” explains David Plank, managing principal at WRSS Food & Nutrition Insights.
A limiting amino acid score is calculated for the finished product based on the proportionate sum of the ingredient essential amino acids and the calculated crude protein total of the combined ingredients.
The digestibility score is then calculated as the proportional average of the known ingredient digestibility. Finally, “the calculated limiting amino acid, crude protein and digestibility are multiplied together to give the total quality protein of the finished product for calculation of %DV.”
“There have also been class action lawsuits under state consumer protection laws for claims about the grams of protein if there is no %DV, or if the %DV is not based on the results of the PDCAAS test,” Krasny continues. “One recent settlement is valued at $2.3 million.”
Some interpret current protein content claim regulations even more stringently. “There is a view that stating crude protein content outside of the Nutrition Facts panel constitutes an implied claim that the product is a good source of protein,” says David Plank, managing principal at WRSS Food & Nutrition Insights.
A test of this interpretation is said to be whether a manufacturer stating the protein content on its label would be willing to have, in equal font size, the statement “not a good source of protein” next to the protein value. If that is unacceptable, even though it is truthful, then it could be indicative that the purpose of such protein labeling is to create the perception that the product is a “good source” of protein, Plank says.
This greatly raises the class action risk profile for this type of labeling. For that reason, Plank explains, some food manufacturers adhere to a standard of only flagging protein content outside of the Nutrition Facts panel when the product contains a threshold level of 10% DV of quality protein which is the minimum requirement for any food product making a protein claim.
How then can a product’s %DV be determined?
“If the finished product fits an established standard of identity, established literature values for the PDCAAS may already exist and can be used as a baseline estimation for determining the %DV,” says Plank.
“Alternatively, if the PDCAAS values of all the input ingredients are known and assuming that the manufacturing process does not impact either the digestibility or limiting amino acids of any components, then the estimated final PDCAAS value for the product can be calculated.”
“Currently, peer-reviewed scientific literature is perhaps the best place to find PDCAAS values of specific plant proteins,” offers Plank. Governmental publications can also be of assistance.
However, Plank advises that for all final labeling of a food product, the finished product should be tested by a qualified lab for its PDCAAS value so that any impacts of processing and formulation on the limiting amino acids and digestibility are considered in accordance with labeling regulations.
So, what does this mean for plant-based protein ingredients?
Protein blending: When 1+1=3
Reasons to include plant sources of protein are as varied as the types of ingredients themselves. Plant-based meat alternatives (e.g., Archer Daniel Midland’s soy-based textured vegetable proteins) have been used for half a century in blended meat products.
Protein concentrates and isolates such as from brown rice, soy and a growing number from other plant sources are used both for their physiochemical (functional) properties and as fortifiers. Whole foods from seeds and grains such as quinoa to legumes (e.g., beans, chickpeas) to nuts provide consumer-desired taste and texture as well as protein.
For example, “Almonds can be useful in keto-friendly foods due to their composition—about 51% fat, 21% protein and 20% carbs of which 13% is dietary fiber," suggests Plank.
Advances in isolation and extraction technologies have resulted in plant protein isolates with high techno-functional and nutritional properties. Soy, brown rice and more recently potato protein isolates are examples.
However, many plant protein-based foods and beverages struggle to provide consumer-expected protein levels, especially when diluted versions are used. A 2018 study by IPSOS for DMI and the National Dairy Council found that 77% of consumers believe almond milk has the same or more protein than dairy milk; 75% and 62% say the same for soymilk and coconut milk respectively. The high PDCAAS for soy means soy-based alternatives to dairy often compare well with dairy-based ones, however others fall short due to lower PDCAAS values.
This challenge most often arises when only one protein source is used. Protein blending can come to the rescue.
Most plant foods are incomplete protein sources; that is, they do not have enough of one or more essential amino acids to be considered optimally balanced for human nutrition. When two or more incomplete proteins can help compensate for each other’s lack of amino acids, they are considered complimentary. When used together a higher PDCAAS results.
For example, “the protein content of hemp seed meal is about 41%,” said Kelley Fitzpatrick of NutriScience Solutions Inc. Although it has more methionine than is often found in plant proteins, its somewhat low PDCAAS value is due in part to a low lysine level. PDCAAS values can be increased when it is combined with pea protein (low in methionine but relatively high in lysine) or pulses such as common beans.
The Pulse Canada publication "Protein Quality of Cooked Pulses" notes “pulse protein is higher in lysine and lower in sulphur amino acids than cereals grains such as wheat and rice, which are lower in lysine and higher in sulphur amino acids.” It advises that the “addition of pulses to either wheat or rice increases the overall PDCAAS values from 0.43 and 0.67 in the individual pulse or cereal [respectively] to 0.71 and 0.75 in the blends.” Suggested blend ratios are given for wheat or rice flour combined with lentils, black beans, protein concentrates (from pea or soy) or pea protein isolates.
While Pollan's advice to eat mostly plants may be on solid ground, "don't eat anything with more than five ingredients" is less so. Product formulators would do well to head labeling laws and understand the benefits of complimentary protein blends.