How plant-based burgers stack up against meat burgers in protein quality


by Lauren Quinn, University of Illinois at Urbana-Champaign

via MedicalXpress - November 15, 2021


Plant-based burgers often promise protein comparable to their animal-based counterparts, but the way protein is expressed on current nutrition labelsóa single generic value expressed in gramsócan be misleading. That's because the human body does not use "protein" per se. Instead, it needs essential amino acids, which are present in proteins, but the concentration and digestibility of amino acids are different among protein sources.


To account for these differences, a new standard for protein quality, the digestible indispensable amino acid score (DIAAS), was developed by the U.N.'s Food and Agriculture Organization (FAO) about a decade ago. It specifically focuses on the digestibility of essential amino acids, and aims to put more accurate tools in the hands of nutritionists and food assistance programs the world over.


A new study from the University of Illinois and Colorado State University leverages the DIAAS system to understand protein quality in beef and pork burgers and plant-based burgers from Impossible and Beyond Meat.


The researchers fed pork burgers, 80% and 93% lean beef burgers, the soy-based Impossible Burger, and pea-based Beyond Burger to pigs, the FAO's recommended research subject for DIAAS studies. They then measured digestibility of individual essential amino acids, and used those digestibility scores to compute DIAAS values.


Both beef and pork burgers, served without buns, scored as "excellent" sources of protein (DIAAS scores 100+, for people of all ages). The Impossible Burger, when served without a bun, also scored as an excellent protein source for ages 3 and up, but not for children less than 3 years old. With a value of 83, the bunless Beyond Burger was a "good" source of protein for ages 3 and up.


"We have previously observed that animal proteins have greater DIAAS values than plant-based proteins and that is also what we observed in this experiment," says Hans H. Stein, professor in the Department of Animal Sciences and the Division of Nutritional Sciences at Illinois and co-author on the European Journal of Nutrition study.


Burger patties are typically eaten with a bun, so the researchers also looked at the protein quality of patties and buns together. Because grain products, like hamburger buns, offer low protein quality, feeding the bun and the patties together reduced DIAAS values...