Sustainability and circular economy of food production are among the main market trends that have led to the search for innovative solutions, such as using raw materials not typical of human food. In this sense, the exploitation of undervalued natural resources, particularly regarding low-cost and highly available vegetable matrices in Portugal, such as acorns, is possible. Furthermore, acorns are one of the most promising natural resources to be considered nationally and internationally due to their nutritional benefits. Hence, their valorization is an essential factor of sustainability nowadays. Therefore, this project aims to characterize acorns by analyzing their chemical composition and bioactivity toward inhibiting enzymes related to cardiovascular diseases.

After being collected in a forest, acorns were washed and dehydrated at 41°C for 72 h. After this process, the seed and pericarp of the fruit were separated. Finally, a proximate analysis was performed where moisture, ash, lipids and proteins were determined, and the values obtained in mass percentage, on a dry basis, were 9.95 ± 0.24, 1.92 ± 0.03, 3.83 ± 0.34 and 3.72 ± 0.07, respectively. Regarding acorn's bioactivities, α-glucosidase and α-amylase inhibition assays were performed. The concentration of acorn extract that inhibits 50% of the enzyme α-glucosidase is 29.8 µg/mL showing its great potential as an antidiabetic agent. However, no inhibition of the α-amylase was registered.

As future work, it is intended to perform further analyses of the chemical composition of the acorn, such as the content of carbohydrates, fibres, and minerals, among others, and study their biological characterization to assess its potential value as a functional food.

Acknowledgements

The authors are grateful for the financial support from REQUIMTE/LAQV—UIDB/50006/2020, UIDP/50006/2020 and LA/P/0008/2020, financed by FCT/MCTES and the project SYSTEMIC, "An integrated approach to the challenge of sustainable food systems: adaptive and mitigatory strategies to address climate change and malnutrition". The Knowledge hub on Nutrition and Food Security received funding from national research funding parties in Belgium (FWO), France (INRA), Germany (BLE), Italy (MIPAAF), Latvia (IZM), Norway (RCN), Portugal (FCT), and Spain (AEI) in a joint action of JPI HDHL, JPI-OCEANS, and FACCE-JPI launched in 2019 under the ERA-NET ERA-HDHL (n° 696295).