Bravo de Esmolfe (BE) is a traditional Portuguese apple highly appreciated by consumers due to its peculiar flavor and aroma. This apple contains higher concentration of phenolic compounds than other cultivars and is thus considered a rich source of antioxidants. Its sensorial and functional properties have attracted farmers’ associations to increase BE production. However, a large quantity of apples is wasted due to storage/transportation procedures that impact BE’s quality attributes. In this work, we applied high-pressure extraction methodologies to generate antioxidant-rich fractions from BE residues aiming at adding high value to these agro-food by-products. We performed a first extraction step using supercritical CO₂, followed by a second extraction step where different CO₂ + ethanol mixtures (10–100% v/v) were tested. All experiments were carried out at 25 MPa and 50 °C. Extracts were characterized in terms of global yield, phenolic content and antioxidant activity using chemical (ORAC, HOSC, HORAC) and cell-based assays (CAA). We demonstrated that, although the pressurized 100% ethanol condition promoted the highest recovery of phenolic compounds (509 ± 8 mg GAE/100 g BE residues), the extract obtained with 40% ethanol presented the highest CAA (1.50 ± 0.24 µmol QE/g dw) and ORAC (285 ± 16 µmol TEAC/g dw), as well as HOSC and HORAC values, which correlated with its content of epicatechin and procyanidin B2. Noteworthy, this fraction inhibited free radical production in human neurospheroids derived from NT2 cells, a robust 3D cell model for neuroprotective testing.

中文翻译：

---

使用高压技术从 Bravo de Esmolfe 苹果渣中提取富含抗氧化剂的提取物

Bravo de Esmolfe (BE) 是一种传统的葡萄牙苹果，因其独特的风味和香气而备受消费者青睐。这种苹果含有比其他品种更高浓度的酚类化合物，因此被认为是抗氧化剂的丰富来源。其感官和功能特性已吸引农民协会增加 BE 产量。然而，由于影响 BE 质量属性的储存/运输程序，大量苹果被浪费了。在这项工作中，我们应用高压提取方法从 BE 残留物中生成富含抗氧化剂的部分，旨在为这些农业食品副产品增加高价值。我们使用超临界 CO ₂进行了第一个提取步骤，然后使用不同的 CO ₂进行了第二个提取步骤+ 乙醇混合物（10–100% v / v) 进行了测试。所有实验均在 25 MPa 和 50 °C 下进行。使用化学（ORAC、HOSC、HORAC）和基于细胞的测定（CAA）对提取物的总产量、酚类含量和抗氧化活性进行表征。我们证明，虽然加压的 100% 乙醇条件促进了酚类化合物的最高回收率（509 ± 8 mg GAE/100 g BE 残留物），但用 40% 乙醇获得的提取物表现出最高的 CAA（1.50 ± 0.24 µmol QE/g dw) 和 ORAC (285 ± 16 µmol TEAC/g dw)，以及与表儿茶素和原花青素 B2 含量相关的 HOSC 和 HORAC 值。值得注意的是，该部分抑制了源自 NT2 细胞的人类神经球体中自由基的产生，NT2 细胞是一种用于神经保护测试的强大 3D 细胞模型。