Anti-nutritional factors in plant-derived milk: a review on effects and effective reduction methods

Abstract

Growing consumer demand for healthy and sustainable food options has increased the consumption of plant-based milk alternatives (PBMAs) to unprecedented levels. While PBMAs offer nutritional and functional variety to consumers, their formulations differ in nutritional quality and nutrient bioavailability due to varying concentrations of antinutritional factors (ANFs). Classes of ANFs include phytic acid, tannins, oxalates, saponins, lectins, and protease inhibitors. Herein, we review the presence, mechanisms of action, nutritional importance, and processing-induced fate of major ANFs in plant-based milk matrices. Special consideration is given to differentiating between results reported for raw plant materials and those reported for laboratory-prepared and commercially available PBMAs, as extraction, soaking, germination, filtration, thermal processing, fermentation, enzymatic hydrolysis, and other processing treatments can significantly alter residual ANF concentrations and bioavailability. Where possible, reported evidence of ANF reduction is quantitatively consolidated by major processing approach. Comparison of methods also considers efficacy, nutritional and sensory implications, time requirements, scalability, cost, environmental impact, and concomitant loss of desirable nutrients and bioactive compounds. The determinants of the nutritional outcomes of residual ANFs are also discussed, including mineral fortification and supplementation, phytase activity, ANF–ANF interactions, protein–phenolic and mineral–phytate complexation, gastrointestinal digestion, and microbiota. Commercial PBMAs are reviewed separately from laboratory-prepared samples, as processing techniques and fortification practices can lead to marked compositional differences from their raw-material and laboratory counterparts. Lastly, emerging technologies aimed at minimizing ANFs, including selective enzymatic treatment, low-ANF crops, genome editing, omics-assisted breeding, precision fermentation, and sustainable food processing technologies, are highlighted. Overall, this review attempts to bridge ANF occurrence, processing alterations, residual bioavailability, nutritional implications, technological functionality, and environmental impact to aid in the design of nutritionally enhanced and environmentally sustainable PBMAs.