Laboratory of Food Chemistry and Biochemistry, School of Agriculture, Aristotle University of Thessaloniki (AUTH), 54124 Thessaloniki, Greece.
Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Molecules. 2024 May 21;29(11):2424. doi: 10.3390/molecules29112424.
The pomegranate processing industry generates worldwide enormous amounts of by-products, such as pomegranate peels (PPs), which constitute a rich source of phenolic compounds. In this view, PPs could be exploited as a sustainable source of ellagic acid, which is a compound that possesses various biological actions. The present study aimed at the liberation of ellagic acid from its bound forms via ultrasound-assisted alkaline hydrolysis, which was optimized using response surface methodology. The effects of duration of sonication, solvent:solid ratio, and NaOH concentration on total phenol content (TPC), antioxidant activity, and punicalagin and ellagic acid content were investigated. Using the optimum hydrolysis conditions (i.e., 32 min, 1:48 /, 1.5 mol/L NaOH), the experimental responses were found to be TCP: 4230 ± 190 mg GAE/100 g dry PPs; A: 32,398 ± 1817 µmol Trolox/100 g dry PPs; A: 29,816 ± 1955 µmol Trolox/100 g dry PPs; 59 ± 3 mg punicalagin/100 g dry PPs; and 1457 ± 71 mg ellagic acid/100 g dry PPs. LC-QTOF-MS and GC-MS analysis of the obtained PP extract revealed the presence of various phenolic compounds (e.g., ellagic acid), organic acids (e.g., citric acid), sugars (e.g., fructose) and amino acids (e.g., glycine). The proposed methodology could be of use for food, pharmaceutical, and cosmetics applications, thus reinforcing local economies.
石榴加工业在全球范围内产生了大量的副产物，如石榴皮（PPs），它是酚类化合物的丰富来源。在这种情况下，PPs 可以被开发为一种可持续的鞣花酸来源，鞣花酸是一种具有多种生物活性的化合物。本研究旨在通过超声辅助碱水解从其结合形式中释放鞣花酸，并用响应面法对其进行优化。研究了超声时间、溶剂/固比和 NaOH 浓度对总酚含量（TPC）、抗氧化活性、以及安石榴甙和鞣花酸含量的影响。使用最佳水解条件（即 32 分钟、1:48 /、1.5 mol/L NaOH），实验结果表明 TPC 为 4230±190mg GAE/100g 干 PPs；A 为 32398±1817µmol Trolox/100g 干 PPs；A 为 29816±1955µmol Trolox/100g 干 PPs；59±3mg 安石榴甙/100g 干 PPs；1457±71mg 鞣花酸/100g 干 PPs。对所得 PP 提取物进行 LC-QTOF-MS 和 GC-MS 分析，结果表明存在各种酚类化合物（如鞣花酸）、有机酸（如柠檬酸）、糖（如果糖）和氨基酸（如甘氨酸）。所提出的方法可用于食品、制药和化妆品应用，从而加强地方经济。
