Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal.
LAQV-REQUIMTE - Laboratório Associado, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
Food Funct. 2022 Jun 20;13(12):6636-6647. doi: 10.1039/d1fo04043j.
Acorns are an abundant but despised fruit in Portugal. To explore this resource, the effect of different dehusking methods (thermal dehusking and dehusking by drying) on the phenolic contents and antioxidant activity of different acorn species from Peneda-Gerês National Park was studied. Regarding the free phenolics, the phenolic contents and antioxidant activity values of decreased after thermal dehusking and dehusking by drying. Similar results were observed for the thermally dehusked acorns, despite the increase in gallic acid. However, the phenolic contents and antioxidant activity values increased when acorns were dehusked by drying, despite the decrease in ellagic acid and ORAC antioxidant values. The phenolic content of acorns increased after both dehusking methods due to the increase of ellagic acid, which led to the increase of the ABTS, DPPH, and FRAP antioxidant activity, but the ORAC antioxidant activity decreased. In the bound fraction, the phenolic, flavonoid, and gallic acid contents increased for all species when dehusked by both methods, thus increasing the antioxidant activity values. The thermal dehusking had a very dependent effect on ellagic acid content between species, while the dehusking by drying increased the ellagic acid contents for acorn species.
橡果在葡萄牙是一种丰富但被轻视的水果。为了探索这一资源，研究了不同脱壳方法（热脱壳和干燥脱壳）对佩内达-热尔国家公园不同橡果种酚类含量和抗氧化活性的影响。对于游离酚类，热脱壳和干燥脱壳后，酚类含量和抗氧化活性值降低。热脱壳的 橡果也观察到了类似的结果，尽管没食子酸增加了。然而，当 橡果干燥脱壳时，酚类含量和抗氧化活性值增加，尽管鞣花酸和 ORAC 抗氧化值下降。由于鞣花酸的增加，两种脱壳方法都增加了 橡果的酚类含量，从而增加了 ABTS、DPPH 和 FRAP 抗氧化活性，但 ORAC 抗氧化活性下降。在结合部分，所有种的酚类、类黄酮和没食子酸含量均因两种方法的脱壳而增加，从而提高了抗氧化活性值。热脱壳对种间的鞣花酸含量有很强的依赖性影响，而干燥脱壳增加了橡果种的鞣花酸含量。
