Luksiene Jurgita, Zevzikoviene Augusta, Kazlauskaite Jurga Andreja, Marksa Mindaugas, Majiene Daiva, Zevzikovas Andrejus
Department of Analytical and Toxicological Chemistry, Lithuanian University of Health Sciences, Sukileliu pr. 13, LT-50161 Kaunas, Lithuania.
Department of Drug Technology and Social Pharmacy, Lithuanian University of Health Sciences, Sukileliu pr. 13, LT-50161 Kaunas, Lithuania.
Plants (Basel). 2025 Aug 13;14(16):2524. doi: 10.3390/plants14162524.
Walnut septa, traditionally discarded as waste in walnut processing because they primarily serve a structural function in the walnut fruit, have recently gained attention for their potential abundance of phenolic compounds, suggesting their overlooked value. This study aimed to optimise extraction parameters to maximise the extraction yield of bioactive compounds and explore regional variations in antioxidant activity and chemical composition of L. septa. The experimental variables included extraction methods (maceration, dynamic maceration, ultrasound processing, and reflux extraction), temperature, solvent type (methanol, acetone, and ethanol), and the percentage of water in the solvent. The optimal conditions were determined based on the total phenolic content-reflux extraction using 60% ethanol as a solvent for a duration of 60 min. Samples from 12 different regions in Lithuania, Armenia, and Ukraine were analysed for their phenolic and proanthocyanidin content and antioxidant activity using the CUPRAC method. The total phenolic content ranged from 131.55 to 530.92 mg of gallic acid equivalents per g of dry weight of plant material (mg GAE/g dw), while the proanthocyanidin content varied from 1.14 to 7.65 mg of (-)-epicatechin equivalents per g dry weight of plant material (mg EE/g dw). Among all the regions studied, the Šiauliai sample demonstrated the highest concentrations of phenolic compounds, proanthocyanidins, and antioxidant activity, with statistically significant differences compared to the other samples ( < 0.05). These findings demonstrate that walnut septa are a valuable source of phenolic compounds and antioxidants, with significant potential for developing natural nutraceuticals and antioxidant products.
核桃隔膜在核桃加工过程中传统上被当作废料丢弃，因为它们在核桃果实中主要起结构支撑作用，但最近因其可能富含酚类化合物而受到关注，这表明其价值被忽视了。本研究旨在优化提取参数以最大化生物活性化合物的提取产量，并探究核桃隔膜抗氧化活性和化学成分的区域差异。实验变量包括提取方法（浸渍、动态浸渍、超声处理和回流提取）、温度、溶剂类型（甲醇、丙酮和乙醇）以及溶剂中的水含量百分比。基于总酚含量确定了最佳条件——以60%乙醇为溶剂进行60分钟的回流提取。使用CUPRAC方法分析了来自立陶宛、亚美尼亚和乌克兰12个不同地区的样品的酚类、原花青素含量和抗氧化活性。总酚含量范围为每克植物材料干重131.55至530.92毫克没食子酸当量（mg GAE/g dw），而原花青素含量从每克植物材料干重1.14至7.65毫克（-）-表儿茶素当量（mg EE/g dw）不等。在所研究的所有地区中，希奥利艾的样品显示出酚类化合物、原花青素和抗氧化活性的浓度最高，与其他样品相比具有统计学显著差异（<0.05）。这些发现表明核桃隔膜是酚类化合物和抗氧化剂的宝贵来源，在开发天然营养保健品和抗氧化产品方面具有巨大潜力。
