Food Science and Technology Programme, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
Food Science and Technology Programme, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Jiangsu 215123, China.
Food Chem. 2018 Aug 30;258:111-117. doi: 10.1016/j.foodchem.2018.03.001. Epub 2018 Mar 5.
The acorns of Quercus fabri Hance tree, or the mandarin duck fruits have been consumed by locals in the form of noodle, yet there is little scientific study. We found that they have much lower digestibility compared with that of rice flour. Solvent extraction using hexane, dichloromethane, and acetone-ethanol-water (AEW) mixture yielded three fractions but the starch hydrolase inhibitors were only found in the AEW fraction. Using assay-guided fractionation of the extracts, we were able to further separate the active compounds by using Sephadex LH-20 column and characterize the inhibitor chemical identities by LC-MS. The main active compounds are ellagitannins including pedunculagin, punicalagin, castalagin, and eucalbanin. Our results indicate that the acorns from Quercus fabri Hance have potential for preparation of low glycemic index foods due to the endogenous starch hydrolase inhibitors.
麻栎橡子，又称鸳鸯果，当地居民常将其制成面条食用，但目前针对其的科学研究较少。我们发现，与米粉相比，麻栎橡子的消化率要低得多。使用正己烷、二氯甲烷和丙酮-乙醇-水（AEW）混合物进行溶剂萃取可得到三个馏分，但只有 AEW 馏分中含有淀粉水解酶抑制剂。通过采用提取物的基于测定的分级分离，我们可以使用 Sephadex LH-20 柱进一步分离活性化合物，并通过 LC-MS 鉴定抑制剂的化学性质。主要的活性化合物为鞣花单宁，包括栗木鞣素、安石榴甙、苛性李鞣酸和诃子鞣酸。我们的结果表明，由于含有内源性淀粉水解酶抑制剂，麻栎橡子具有开发低血糖指数食品的潜力。
