Rice and pea fermentation boosts protein efficiency in plant-based probiotic products

30 Jul 2021 --- Fermenting pea and rice dairy alternatives with probiotic strains can yield higher quality protein that is more digestible. This was the conclusion of a study by the Institut National de la Recherche Scientifique (INRS), Canada, in collaboration with Bio-K+, a probiotics company.

The findings shed new light on probiotics’ capabilities as a functional ingredient beyond their digestive health benefits. Notably, the rice and pea beverages fermented with Bio-K+’s Lactobacillus acidophilus CL1285, L. casei LBC80R and L. rhamnosus CLR2 yielded the same quality of protein as casein, an animal protein found in milk.

These insights may help formulators approximate dairy’s protein content in cultured plant-based alternatives, in addition to providing boosts to gut health with probiotic strains. 

Breaking it down with fermentation 
One of the primary dilemmas with plant-based proteins is their digestibility, notes Professor Monique Lacroix of the INRS, who led the team of researchers.

“They often are insoluble in water and under globular form. That means our digestive enzymes have more difficulty breaking them down.”

“Animal proteins, on the other hand, usually take the form of elongated fibers that are easily processed by digestive enzymes.”

Matching protein content in plant-based formulations to traditional dairy is a long-standing industry challenge.Researchers discovered that lactic acid bacteria could predigest pea and rice proteins. For this, the plant proteins need to be added before the fermentation stage of beverage production.

Fermentation allowed for the production of peptides (protein fragments) resulting from the breakdown of proteins during fermentation, facilitating their absorption during digestion. 

The findings were published in the Journal of Food Science. 

Measuring protein’s impact
The protein quality was determined as the protein efficiency ratio (PER), net protein ratio (NPR), and the apparent (AD) and the true digestibility (TD) evaluated in vivo. 

The probiotic beverage was incorporated into a rat diet at a final concentration of 10 percent protein for the evaluation of the PER, the NPR, the AD and the TD. 

The protein digestibility amino acid score was also calculated. Results showed that the beverages enriched with fermentation had no effect on the TD but significantly increased the PER and the NPR from 1.88 to 2.32 and from 1.66 to 2.30, respectively. 

Thus, the fermentation increased the protein quality of the PRF probiotic beverage.

Completing the amino acid profile
Getting enough protein content in plant-based formulations has proved to be challenging. 

With the exception of soy, plant proteins are deficient in certain essential amino acids, which the body needs to get through diet.

Complementary plant proteins can be combined to form a complete amino acid profile.To make up for the amino acid gaps in some plant proteins, some food and nutrition formulators blend two plant sources with different amino acid profiles, resulting in a complete set.

For this study, researchers combined pea and rice proteins to counterbalance essential amino acids. Fava and rice may also be paired to create meat alternatives that contain complete protein. 

Future forward
Vegan probiotic beverages represent the convergence of two highly impactful industry trends influencing NPD: plant-based and gut health. 

Chr. Hansen has dubbed the market for fermented plant bases a “lighthouse” for the company, referring to a business area with long-term revenue potential in excess of €100 (US$118 million) million. 

Recently the company Ayo harnessed Chr. Hansen's Bifidobacterium animalis subsp. lactis, or BB-12, in an almond yogurt, positioned for immunity and digestive health.

Meanwhile, a Special Report on probiotics found the ingredient’s presence in supplements is subsiding, with increased interest in food and beverage applications. 

By Missy Green