Sorghum starch and protein digestibility: mechanisms, modifications, and health implications

Authors: Olson, Douglas; MUNIANDY, ANBUHKANI - University Of Idaho; ZHU, LIJIA - University Of Idaho; ZAREI, MOHAMMAD - Virginia Tech; SCHWARZ, MICHAEL - Virginia Tech; Bean, Scott; Smith, Brennan

Submitted to: Comprehensive Reviews in Food Science and Food Safety
Publication Type: Review Article
Publication Acceptance Date: 5/4/2026
Publication Date: 5/12/2026
Citation: Olson, D.W., Muniandy, A., Zhu, L., Zarei, M., Schwarz, M., Bean, S.R., Smith, B. 2026. Sorghum starch and protein digestibility: mechanisms, modifications, and health implications. Comprehensive Reviews in Food Science and Food Safety. 15(10):1681. https://doi.org/10.3390/foods15101681.
DOI: https://doi.org/10.3390/foods15101681

Interpretive Summary: Sorghum is a drought-resistant, gluten-free grain that supports food security in semi-arid regions and benefits celiac patients. However, cooking sorghum reduces its digestibility compared to other grains due to protein complexes (kafirins) and enzyme inhibitors that limit starch breakdown. This is a challenge for malnourished individuals and those with celiac disease who rely on sorghum as a staple. However, certain processing methods can improve digestibility by breaking down these barriers. On the other hand, sorghum’s lower digestibility can be beneficial for diabetics by helping regulate blood sugar levels. Additionally, consuming sorghum, particularly waxy varieties, may influence gut microbiome composition. Optimizing processing methods can make sorghum more suitable for different dietary needs.

Technical Abstract: This review examines sorghum digestibility from molecular structure to clinical implications, focusing on compositional factors, processing methods, and health outcomes. We evaluate how sorghum’s unique protein–starch interactions influence digestibility and explore emerging technologies that can modulate these properties for targeted nutritional benefits. Cooked sorghum generally has lower digestibility than raw sorghum and other cereals due to heat-induced protein–starch cross-linking and the formation of disulfide bonds by sorghum proteins (kafirins), which restrict enzymatic access. Enzyme inhibitors in sorghum further reduce starch hydrolysis. This reduced digestibility may negatively impact malnourished individuals and those relying on sorghum as a dietary staple. However, it can be advantageous to individuals with diabetes by lowering postprandial blood glucose levels. Sorghum consumption may also beneficially influence the gut microbiome. Certain processing methods have been shown to significantly enhance digestibility while preserving beneficial bioactive compounds. Improving digestibility through these strategies may enhance sorghum’s value for vulnerable populations while maintaining its metabolic advantages. Balancing increased nutrient bioavailability with preservation of beneficial functional properties is critical for optimizing sorghum as a health-promoting grain across diverse populations.