Potential of North American Acorns as an Underutilized Food Source: Morphology, Nutritional Composition and Content of Bioactive Compounds in Quercus virginiana Acorns of Different Natural Populations

Quercus acorns have been part of animal or human diets; however, their nutritional potential depends on morphological and chemical characteristics highly influenced by genetic and geographical factors. Research on the Quercus genus has focused on Asian and European species overlooking the American taxa. Therefore, this study aimed to evaluate the morphological and nutritional characteristics, and the content and profile of bioactive compounds of acorns from four populations of the American species Quercus virginiana from the state of Chihuahua, Mexico. Discriminant function analysis showed a well-established group formed by the two southern populations (CH), while the two northern populations were separated into different groups (CJA and CJB). CH populations showed smaller seeds (1.4 g, 2.0 cm length) and higher starch (57–58%), oleic acid (65–70%), phenolic compounds (78–176 mg GAE/g), flavonoids (29–37 mg CE/g), and antioxidant activity (278–282 μmol TE/g). Acorns from the CJA population were the largest (2.3 g, 2.4 cm length) and displayed the highest protein content (7.0%). Acorns from the CJB population showed the highest values for ash (2.2%), sugars (13.8%), palmitic and linoleic acids (19.1%), and condensed tannins (0.26 CE/g). Fourteen polyphenolic compounds were identified: twelve hydrolysable tannins; one hydroxycinnamic acid, and one flavonol. These variations reflected the impact of local climatic and geographic conditions and may influence the potential use of Quercus acorns in sustainable agriculture and food development.