The impact of amino acid reference patterns on the in vitro protein quality of pre-treated pulse products

Protein quality assessment can be used to substantiate and communicate a protein content claim to consumers. Proposed over a decade ago, the digestible indispensable amino acid score (DIAAS) was positioned to replace the current method of protein quality evaluation, the protein digestibility correct amino acid score (PDCAAS). With national guidelines in both the US and Canada posed to increase the consumption of protein from plant-based sources, it is not known to what extent the adoption of DIAAS may impose on communicating protein content claims. In this study, p</span>rotein digestibility using an in vitro (IV) method as a surrogate for in vivo protein digestibility was used to investigate protein quality assessed by both the PDCAAS and DIAAS. Pulses, including yellow peas, green lentils, Kabuli chickpeas, and navy beans were pre-treated by roasting, micronization, germination or untreated. Three products were produced from these pulses, including a pan bread (20% pulse), spaghetti pasta (50% pulse) and a puffed extrudate (60-80% pulse). The protein digestibility of all products was high (≥90%) and significantly (P < 0.05) improved IV-PDCAAS and IV-DIAAS over their cereal-based control. Navy beans subject to micronization or untreated had the lowest protein quality for extrudate and pasta products respectively, but the highest in pre-roasted bread. Micronized yellow peas demonstrated the highest protein quality in pasta and extrudate products, with the exception of IV-DIAAS in roasted chickpea extrudates. The “Good source of protein” claim for any pulse-based bread or pasta could be obtained following either protein quality assessment, whereas only micronized yellow peas may obtain this claim in an extruded snack. Either methodology may therefore be appropriate for communicating content claims in high protein plant-based foods.