Mitigating anti-nutritional factors in oats: Strategic processing approaches to enhance nutrient bioavailability

With the growing demand for plant-based products, oats (Avena sativa L.) have become a key cereal of interest due to their valuable nutritional profile and diverse functional components. They contain notable amounts of protein (12-20 %), unsaturated fatty acids (78-81.5 % of total lipids), carbohydrates (60-75.7 %), β-glucan (4-8.5 %), essential vitamins, minerals, and various bioactive compounds. However, oats also contain antinutritional factors (ANFs), including phytates, saponins, tannins, oxalates, enzyme inhibitors, and lectins, which can chelate minerals and inhibit digestive enzymes, thereby reducing nutrient digestibility and bioavailability. Despite extensive research on ANFs in other crops, comprehensive evaluations focused on oats remain scarce. This review seeks to better understand the processes that mitigate ANFs and enhance nutrient bioavailability in oats. It will critically examine processing strategies with the potential to reduce ANFs in oats and oat-derived products, focusing on dehulling, milling, soaking, germination, malting, fermentation, enzymatic treatment, toasting, autoclaving, steaming, kilning, microwave heating, and extrusion. These methods employ mechanisms such as physical removal, enzymatic hydrolysis, and thermal degradation, achieving significant reductions in ANF content (e.g., phytate reduction up to 99 % through germination and malting, and substantial declines in tannins, saponins, and enzyme inhibitors via fermentation, steaming, and microwave heating). While these approaches enhance nutrient bioavailability, challenges remain concerning nutrient losses, industrial scalability, and retention of bioactive compounds. This review emphasizes the need for precise ANF quantification, novel and combined processing technologies, and improved nutritional quality in oat-based products.