Gastrointestinal digestibility of pulse proteins: amino acid bioavailability, peptide release, and bioactivity

Increasing interest in plant-based proteins has spotlighted pulses, such as Dry Pea (Pisum sativum L.) and Beans (Phaseolus vulgaris), as promising ingredients for food product development. Pulses are rich in soluble proteins; however, the considerable diversity among their varieties results in differences in storage protein composition. These differences significantly influence protein digestibility as well as the bio-accessibility and bioavailability of essential amino acids. Furthermore, pulses naturally contain phytochemicals and anti-nutritional factors, including phytic acid and protease inhibitors (e.g., trypsin and chymotrypsin inhibitors), which can impair digestion and absorption, particularly when consumed in their unprocessed forms.

Our recent investigations focused on assessing the protein digestibility, bio-accessibility, and in-vitro bioavailability of essential amino acids across the four pea cultivars (Carver, Profit, Earlystar, and Spider) and three bean market classes (Black, Great Northern, and Pinto) and, grown in Nebraska. We evaluated how these pulses influence protein breakdown during GI-digestion and the subsequent bio-accessibility and absorption of amino acids. In addition, we examined the bioactivity of gastrointestinal digesta from these pulses, focusing on their in-vitro anti-inflammatory and antioxidant properties. Our findings revealed synergistic effects among various compounds in the digesta that could contribute to their observed bioactivity and can differ among different cultivars or market classes.

This comprehensive analysis highlights the critical role of pulse cultivars and varieties, emphasizing that generalizing gastrointestinal digestibility, bioavailability, and bioactivity across pulses is inappropriate. A deeper understanding of the complexity of storage proteins for each cultivar or market class of pulses is essential to elucidate their potential as a source of plant-based proteins.