Exploring the Potential of Acorns: An Opportunity for Sustainable Food

Despite being an abundant resource in Portugal, the acorn remains largely undervalued, with most of it either wasted or used for animal feed. However, its nutritional profile reveals tremendous potential for innovative food applications. Rich in carbohydrates, fibre, antioxidant compounds, and unsaturated fatty acids, the acorn stands out as a promising raw material — particularly in the form of flour. The nutritional composition of acorn flours from four native oak species has been scientifically validated by the Portuguese Catholic University: Quercus rotundifolia, Q. pyrenaica, Q. suber, and Q. robur.

These flours contain approximately 6–13% lipids, 68–76% carbohydrates — including 26–54% starch (of which 40–50% is resistant starch) — and 15–31% fibre. The inclusion of resistant starch in the diet may offer health benefits, particularly in improving glucose tolerance. Their energy value is around 400 kcal per 100 g, and they also contain essential minerals such as potassium, phosphorus, magnesium, and calcium. Moreover, these flours are rich in beneficial fatty acids, including oleic, linoleic, and palmitic acids. Additionally, they are considered good sources of vitamin E and phenolic compounds such as gallic and ellagic acids, which provide notable antioxidant properties — further enhancing their nutritional value. This rich nutritional composition paves the way for the development of more sustainable and naturally gluten-free food products, promoting not only healthier diets but also the valorisation of an underutilised local resource with significant potential.