PDCAAS quandary

When a protein claim is made on yogurt, the FDA requires that the % daily value (DV) for protein be declared and modified to reflect the protein digestibility-corrected amino acid score (PDCAAS). Dairy proteins are complete proteins, so no adjustments to DV are needed.

Soy has a PDCAAS of 1.0, but many of the other plant proteins being used in the dairy space have lower scores.

“Chickpea and fava bean proteins score a 0.6; oat protein is slightly higher at 0.67,” says Christine Addington, senior dairy technical service specialist, Cargill. “Plant proteins can be blended with complementary proteins to create a complete protein source. [Cargill’s] Puris pea protein has a PDCAAS of 0.8 and can be blended with a rice protein to create a complete amino acid profile and achieve the target protein claim.”

Plant protein fractions suitable for use in yogurt will have unique amino acid profiles and digestibility values. Finding accurate values can be a challenge. When combining plant proteins, a weighted digestibility value must be used.

Texture challenges

Dairy proteins are unique and provide functionality that can be controlled and tailored by process and formulation. Specialty dairy ingredients designed for high-protein yogurt result in products with a smoother texture, creamy mouthfeel, improved gelation and reduced whey separation.

“In high-protein yogurt, the added protein type (milk or whey), protein concentration, heat stability of the protein, calcium content of the protein, salt, gum system and other ingredients are very important to get the desired consistency,” says Khilendra Bhanduriya, senior product development scientist, Milk Specialties Global. “Critical processing parameters that affect consistency include hydration of the protein, heating step (temp/time), homogenization, starter and inoculation temperature, [and] shear rate in the post-fermentation smoothing process. … Storage time and temperature are also important factors.”

Plant based yogurts rely on starches and hydrocolloids for most of their textural properties.

“At high usage levels, plant proteins often have solubility issues, resulting in negative textural attributes like grittiness or sandiness,” notes Addington. “One option is to use higher amounts of fat. This will deliver a creamier mouthfeel, but can be a turnoff for some health-conscious shoppers.”

Syneresis is another area of concern in yogurt alternatives. Specialty tapioca starches help reduce syneresis, optimize texture and increase cold-storage stability. Pectin is another ingredient that helps control syneresis and improve mouthfeel.

“Plant-based protein requires extensive filtration and extraction to concentrate because the proteins found in a plant’s native state are in a much lower concentration than dairy proteins. This can compromise the functionality and taste of plant proteins,” says Bhanduriya.

Plant proteins behave similarly to whey proteins, notes K.J. Burrington, American Dairy Product Institute’s director – training, education and technical development.

“Their heat stability won’t be as good as casein, and they will not form an acid gel,” she says. “The flavors aren’t even remotely the same, and the ones that are at least mild in flavor would be almond and oat.”

Fermentation can also alter plant protein flavor. Using stronger flavor profiles such as spices is one solution. This will be an interesting category to watch.