Apple pomace as potential source of oxidative stress protecting dihydrochalcones

Phloridzin, a natural dihydrochalcone, exhibits a wide range of beneficial effects and even broader applications, spanning from the pharmaceutical to the food industry. It is found in high concentrations in apple fruit. When apples are processed into juice, approximately 30% of their weight remains as a byproduct known as pomace, making pomace an intriguing candidate as a source of phloridzin. 

In this study, 13 apple cultivars were evaluated for their phloridzin content across different apple parts: flesh, peel, and seeds, as well as in apple juice and the byproduct pomace. The physical characteristics of the apples, including weight, size, starch content, and firmness, were measured to ensure their suitability for comparison. Methanol extracts were analyzed using the Folin–Ciocalteu assay for total phenolic content, HPLC for phloridzin quantification, and the FRAP assay for antioxidant activity.Among the solid parts, seeds exhibited the highest phloridzin content, with an average of 7.2 g/kg of apple dry weight, followed by the peel and flesh. Regarding total phenolic content, the flesh and seeds were comparable, with averages of 8.8 g and 7.8 g of gallic acid equivalent per kg of apple dry weight, respectively. For juices and pomace, phloridzin concentrations were similar across all samples, ranging from 0.32 to 0.57 g/kg of apple dry weight. In terms of total phenolic content, untreated juice contained an average of 42 g/kg of apple dry weight. 

Antioxidant activity was highest in the peel for the solid parts, with an average of 11.4 g of ascorbic acid equivalent per kg of apple dry weight, followed by the flesh and seeds. Among the juices, the treated juice exhibited the highest antioxidant activity, with an average of 29.7 g/kg of apple dry weight. Given the substantial amount of pomace produced during apple processing, it presents a promising and sustainable source for phloridzin extraction, particularly when using environmentally friendly extraction methods. The data sheet represents the concentrations of each sample resulting from the three primary tests (HPLC, Folin–Ciocalteu assay, and FRAP). Additionally, each apple cultivar's physical characteristics (weight, size, starch, firmness). This project IT-ETN-956257 is funded by Horizon 2020

根皮苷（Phloridzin）作为一种天然二氢查耳酮，具有广泛的有益功效及更广阔的应用场景，涵盖制药至食品工业领域。它在苹果果实中含量较高。苹果加工成果汁时，约30%的重量会残留为名为苹果渣（pomace）的副产物，这使苹果渣成为提取根皮苷的潜在理想来源。

本研究评估了13个苹果品种在不同部位（果肉、果皮、种子）及苹果汁和副产物苹果渣中的根皮苷含量。为确保可比性，测定了苹果的物理特性，包括重量、大小、淀粉含量和硬度。通过福林-肖卡法（Folin–Ciocalteu assay）分析甲醇提取物的总酚含量，采用高效液相色谱法（HPLC）定量根皮苷，利用铁离子还原抗氧化能力法（FRAP assay）评估抗氧化活性。在固体部位中，种子的根皮苷含量最高，平均为7.2 g/kg苹果干重，其次是果皮和果肉。总酚含量方面，果肉与种子相当，分别为每千克苹果干重8.8克和7.8克没食子酸当量。果汁和苹果渣中，所有样品的根皮苷浓度相近，范围在0.32至0.57 g/kg苹果干重之间。未处理果汁的总酚含量平均为42 g/kg苹果干重。

固体部位中，果皮的抗氧化活性最高，平均为每千克苹果干重11.4克抗坏血酸当量，其次是果肉和种子。果汁中，处理过的果汁抗氧化活性最高，平均为29.7 g/kg苹果干重。考虑到苹果加工过程中产生的大量苹果渣，它是提取根皮苷的潜在可持续来源，尤其是采用环保提取方法时。

数据表包含三个主要测试（HPLC、福林-肖卡法、FRAP）所得各样本的浓度数据。此外，还包含各苹果品种的物理特性（重量、大小、淀粉含量、硬度）。本项目IT-ETN-956257由Horizon 2020资助。