Shirzad Habib, Niknam Vahid, Taheri Mehdi, Ebrahimzadeh Hassan
Department of Plant Biology, and Center of Excellence in Phylogeny of Living Organisms in Iran, School of Biology, College of Science, University of Tehran, Tehran, 14155-6455 Iran.
Soil and Water Research Department, Zanjan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Zanjan, Iran.
J Food Sci Technol. 2017 Jul;54(8):2361-2371. doi: 10.1007/s13197-017-2676-7. Epub 2017 Jun 19.
In recent years, there has been an ever growing interest in finding new natural ources of food antioxidants. As a main fruit crop, olive is also valued due to its phenolic-containing leaves. Mathematically based optimization methods are used as powerful tools to extract different antioxidant compounds. The present study is aimed to provide an efficient extraction method for total phenol content (TPC), total flavonoid content (TFC) and antioxidant ability (DPPH scavenging assay and FRAP). The effects of ultrasonic temperature (35-65 °C), ultrasonic time (5-15 min), and ethanol to water ratio (Et: W) (25-75%) were evaluated. Second-order polynomial models were used through a rotatable Box-Behnken design (BBD) consisting of 15 experimental runs with three replicates at the center point. Interactional effects of the studied factors were significant in most cases for all responses. The highest extraction efficiency was found to be fifty-one percent of ethanol (65 °C, 15 min) to water ratio. Under optimal conditions, values for TPC, TFC, DPPHsc and FRAP assay were 183.4 (mg GAE. g DW), 696.77 (mg Quercetin. g DW), 78.98 (DPPHsc %) and 1942 µmol Fe/g DW, respectively. values ( > 0.92) showed that RSM models could efficiently predict the yield of all responses. In the LC-ESI-MS-DAD profiling of the optimized extract, 27 compounds were identified with oleuropein as the main compound. In the present study, olive leaf is introduced as a promising source of natural antioxidant and can be used in food industries following further studies.
近年来，人们对寻找新的天然食品抗氧化剂来源的兴趣与日俱增。作为一种主要的水果作物，橄榄因其含酚类的叶子也受到重视。基于数学的优化方法被用作提取不同抗氧化化合物的有力工具。本研究旨在提供一种高效的提取方法，用于测定总酚含量（TPC）、总黄酮含量（TFC）和抗氧化能力（DPPH清除试验和铁还原抗氧化能力测定法）。评估了超声温度（35 - 65°C）、超声时间（5 - 15分钟）和乙醇与水的比例（Et:W）（25 - 75%）的影响。通过由15次实验运行组成的旋转式Box-Behnken设计（BBD）使用二阶多项式模型，在中心点进行三次重复。在大多数情况下，所研究因素的交互作用对所有响应均具有显著影响。发现最高提取效率是乙醇与水比例为51%（65°C，15分钟）时。在最佳条件下，TPC、TFC、DPPH清除率和铁还原抗氧化能力测定法的值分别为183.4（mg没食子酸当量·g干重）、696.77（mg槲皮素·g干重）、78.98（DPPH清除率%）和1942 μmol铁/g干重。相关系数值（> 0.92）表明响应曲面法模型能够有效地预测所有响应的产量。在优化提取物的液相色谱 - 电喷雾电离 - 质谱 - 二极管阵列检测分析中，鉴定出27种化合物，其中橄榄苦苷为主要化合物。在本研究中，橄榄叶被认为是一种有前景的天然抗氧化剂来源，经过进一步研究后可用于食品工业。
