Lab Studies Validate Non-Animal Methods for Protein Quality Assessment

Nine labs have coordinated a set of studies that support new alternatives to animal-based digestibility testing when protein quality measures are required for labeling food.

Current North American food labeling regulations rely on published animal test-based protein digestibility values for specific food ingredients. For companies developing new foods and ingredients without existing data, animal digestibilty tests pose cost and ethical hurdles.

But in a recent paper, researchers compared results from nine labs for two new simple, cost-effective and ethical methods for evaluating protein digestibility. This research followed Uniform Methods Committee standards of analysis and comes at a time when alternative protein innovation is growing.

Using these new methods, food formulators can make decisions on ingredient and processing choices when taking protein digestibility into consideration. This research was supported by the Protein Committee of the Institute for the Advancement of Food and Nutrition Sciences.

All of the nine Canadian and U.S. laboratories in the study analyzed the same 12 protein ingredients from plants and animals to test how reliably two in vitro (non-animal studies) tests measured protein digestibility. The two methods are called pH-drop and pH-stat. The cross-lab review focused on repeatability and reproducibility, and the results support broader usage of pH-drop and pH-stat. According to the paper, the findings reflect "low interlaboratory variability across samples and confirming stable reproducibility."

Diverse Proteins

The exploration of unconventional and even novel protein sources is expanding to meet growing interest in plant-based diet patterns. Dietary protein quality assessment is increasingly relevant when formulating and processing foods with novel and alternative protein sources.

North American food labeling rules currently require protein digestibility correction factors from animal-based testing as part of evaluating overall protein quality.

But this has created a "paradox" for plant-based and alternative protein companies seeking to meet consumer desires to avoid animal testing for ethical reasons, the authors say. Currently, their products would need to rely on existing data, or for new ingredients, protein digestibility tests would have to be done in animals if the firms plan to make protein claims on food labels in the U.S.

These and other factors collectively limit the widespread assessment of protein quality across the growing diversity of innovative protein sources.

According to the authors, if the in vitro methods were allowed in future by North American regulators, they could be used to communicate protein quality on food products without compromising those who have ethical concerns about test animals.

The paper found: "Overall, the statistical analysis confirmed that both the standardized method of analysis for pH-drop and pH-stat tests exhibit acceptable repeatability and reproducibility, supporting their suitability as standardized screening tools for evaluating ingredient selection and processing effects on protein quality."

While there is more to learn about protein digestibility using these in vitro methods, including the applicability of these tests to hydrolyzed proteins, the researchers conclude "these methods have the potential to reduce reliance on animal testing for early-stage screening and to support innovation in protein food development across diverse food sources."

In response to the paper, Chris Marinangeli from Protein Industries Canada stated: "This work is critical for the ability for industry and consumers to adapt to changing food systems and dietary patterns by, hopefully, expediting protein quality assessments. Also, there are always opportunities for regulatory agencies to adopt new and validated methods that reduce regulatory burden."