An Appetite for Modernizing the Regulatory Framework for Protein Content Claims in Canada

In vitro protein digestibility to replace in vivo digestibility for purposes of nutrient content claim substantiation in North America's context

The reliance by North American regulatory authorities on in vivo rodent bioassays-Protein Correct-Amino Acid Score (PDCAAS) in the U.S. and Protein Efficiency Ratio (PER) in Canada-to measure the protein quality for protein content claim substantiation represents a major barrier for innovation in the development and marketing of protein foods. Although FAO in 2013 proposed a new method (Digestible Indispensable Amino Acid Score, DIAAS), it is still not used for protein content claim substantiation in any jurisdiction. Together with public health efforts to increase the consumption of plant-based foods, removing hurdles is key to incentivizing the food industry to measure protein digestibility in making food formulation decisions as well as in claiming protein content on product labels. To address this issue, a pathway has been proposed to position alternative methods for in vitro protein digestibility in collaborative studies to generate the data necessary for method approval by a certifying body. The latter is critical to the potential recognition of these methods by both Health Canada and the US FDA. The purpose of this article is to briefly summarize the state-of-the-art in the field, to inform the research community of next steps, and to describe the path engaging collaborative laboratories in a proficiency test as the first step in moving forward toward acceptance of in vitro digestibility methods. Throughout, a consultative and iterative process will be utilized to ensure the program goals are met. Success will be achieved when the proposed path results in the acceptance of an in vitro methods for protein digestibility used for PDCAAS determinations, which will enable increased protein analyses and improved nutrition labeling of protein foods.

Options for substantiating protein content claims for conventional foods

In Canada and the United States, front-of-package protein content claims require data to support the quality of the protein. In general, protein quality reflects the product of the amino acid composition of the food protein relative to human amino acid requirements and a measure of digestibility. The currently accepted method in both jurisdictions is the protein digestibility-corrected amino acid score (PDCAAS) that requires the measurement of true fecal protein (nitrogen) digestibility. The latter must be measured in vivo using a rat model. This requirement for animal testing is inconsistent with international efforts to reduce the usage of animals in testing for regulatory purposes. The current commentary positions four options to remove the need to use animal testing for determining protein quality, when considering protein content claim substantiation. These options include (i) a focus on protein quantity alone; (ii) the use of the amino acid score alone, with no correction for digestibility; (iii) the use of a fixed digestibility coefficient to estimate protein quality; and (iv) the use of in vitro methods to measure protein and/or amino acid digestibility. The relative merits and deficiencies of the options are positioned with the goal of encouraging dialogue within the regulatory agencies to move towards alternative approaches for substantiating protein content claims on foods, including those derived from plant-based sources.

Validation of a Triplex Quantitative Polymerase Chain Reaction Assay for Detection and Quantification of Traditional Protein Sources, Pisum sativum L. and Glycine max (L.) Merr., in Protein Powder Mixtures

Several botanicals have been traditionally used as protein sources, including the leguminous Pisum sativum L. and Glycine max (L.) Merr. While a rich history exists of cultivating these plants for their whole, protein-rich grain, modern use as powdered supplements present a new challenge in material authentication. The absence of clear morphological identifiers of an intact plant and the existence of long, complex supply chains behoove industry to create quick, reliable analytical tools to identify the botanical source of a protein product (many of which contain multiple sources). The utility of molecular tools for plant-based protein powder authentication is gaining traction, but few validated tools exist. Multiplex quantitative polymerase chain reaction (qPCR) can provide an economical means by which sources can be identified and relative proportions quantified. We followed established guidelines for the design, optimization, and validation of qPCR assay, and developed a triplex qPCR assay that can amplify and quantify pea and soy DNA targets, normalized by a calibrator. The assay was evaluated for analytical specificity, analytical sensitivity, efficiency, precision, dynamic range, repeatability, and reproducibility. We tested the quantitative ability of the assay using pea and soy DNA mixtures, finding exceptional quantitative linearity for both targets - 0.9983 (p < 0.0001) for soy and 0.9915 (p < 0.0001) for pea. Ratios based on mass of protein powder were also tested, resulting in non-linear patterns in data that suggested the requirement of further sample preparation optimization or algorithmic correction. Variation in fragment size within different lots of commercial protein powder samples was also analyzed, revealing low SD among lots. Ultimately, this study demonstrated the utility of qPCR in the context of protein powder mixtures and highlighted key considerations to take into account for commercial implementation.

Translating "protein foods" from the new Canada's Food Guide to consumers: knowledge gaps and recommendations

The revised version of Canada's Food Guide, released in January 2019, issued new guidance by combining meat and alternatives with milk and alternatives into a single group called "protein foods" and emphasized selecting plant-based foods from this category more often. Though the changes represent a simple depiction of a healthy plate, the new Food Guide has opened knowledge gaps about protein foods and exposed new concerns about the interpretation and implementation of the Food Guide among vulnerable groups, particularly children and the elderly. To address key knowledge and research gaps, nutrition leaders need to reach a consensus on key messages to best inform the development of tools and resources to support practitioners in translating messages to consumers, including foodservice standards. Among consumers, families with young children are a primary target for these resources as they develop their life-long habits to ensure they have the knowledge and skills to select, prepare, and consume nutrient-rich protein foods. The new Food Guide provides an opportunity to address the existing knowledge gaps, develop tools and resources to support health professionals, and design interventions that will help Canadian families choose, prepare, and eat nutrient-rich protein foods. Novelty An updated Canadian regulatory framework is needed for protein labelling and content/health claims. There are knowledge gaps about protein foods consumption and food literacy needed to optimize nutritional health. Mandatory nutrition policies are needed to safeguard the provision of high-quality protein foods across institutions that serve children and older adults.

Investigating appropriate molecular and chemical methods for ingredient identity testing of plant-based protein powder dietary supplements

Plant-based protein powders are rapidly growing in popularity, and outdated quality assurance tools expose vulnerabilities to adulteration via different methods of "protein spiking". Adequate diagnostic tools are urgently needed to be able to authenticate protein source ingredients and screen for potential adulterants. We explored the application of three diagnostic tools for ingredient identification: targeted PCR with Sanger sequencing, NGS, and LC-MS/MS. We collected 33 samples of common commercial products from the plant-based protein powder market and sought to identify botanical components using the three technologies. We found success in detection with all approaches, with at least one main protein source being identified by at least one approach in all samples. The investigation uncovered challenges to data collection or result interpretation with each technology including but not limited to amplification biases with PCR technologies, potential influence of DNA degradation, and issues with protein solubility during isolation. Ultimately, each platform demonstrated utility along with certain caveats, which epitomized the importance of orthogonality of testing.

Effect of tempering moisture and infrared heating temperature on the nutritional properties of desi chickpea and hull-less barley flours, and their blends

The impact of infrared heating surface temperature and tempering moisture on the nutritional properties of desi chickpea, hull-less barley, and their blends were examined. Specifically, this included changes to the level of anti-nutritive factors (i.e., trypsin/chymotrypsin inhibitors, total phenolics and condensed tannins), amino acid composition and in vitro protein digestibility. Results indicated that both temperature and the tempering/temperature treatment caused a reduction in levels of all anti-nutritional factors for both flours, and the effect was more prominent in the tempering-temperature combination. The amino acid composition of both flours was not substantially changed with tempering or infrared heating. The amino acid scores (AAS) of chickpea and barley flours, as determined by the first limiting amino acid using the FAO/WHO reference pattern found in the case of barley to be limiting in lysine with an AAS of ~0.9, whereas for chickpea flour, threonine was limiting and had an AAS of ~0.6. The in vitro protein digestibility of chickpea samples was found to increase from 76% to 79% with the tempering-heat (135 °C) combination, whereas barley flour increased from 72% to 79% when directly heated to 135 °C (without tempering). In vitro protein digestibility corrected amino acid score (IV-PDCAAS) was found to increase from 65% to 71% for chickpea flour and 44% to 52% for barley flour, respectively with tempering-temperature (135 °C) combination indicating that tempering with infrared heating can improve the nutritional value of both flours. The addition of chickpea flour to the barley flour acted to improve the nutritional properties (IV-PDCAAS), to an extent depending on the concentration of chickpea flour present.