Stoica Florina, Aprodu Iuliana, Enachi Elena, Stănciuc Nicoleta, Condurache Nina Nicoleta, Duță Denisa Eglantina, Bahrim Gabriela Elena, Râpeanu Gabriela
Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, 111 Domneasca Street, 800201 Galati, Romania.
National Institute of Research & Development for Food Bioresources-IBA Bucharest, 6 Dinu Vintila Street, 021102 Bucharest, Romania.
Plants (Basel). 2021 Oct 28;10(11):2330. doi: 10.3390/plants10112330.
This study aimed to investigate the thermal stability and biological activities of the phytochemicals from the red onion skins extract, which are a rich source of anthocyanins. Eight anthocyanins were identified in the extract by high-performance liquid chromatography, the most abundant ones being cyanidin 3--laminaribioside and cyanidin 3--(6″-malonoyl-laminaribioside). The study also involved the assessment of the thermal degradation kinetics of anthocyanins and antioxidant activity in the 75-155 °C temperature range. The thermal degradation kinetics was described using the first-order kinetics model. In terms of thermal stability, increasing the temperature resulted in lower half-life values (t) and higher degradation rate constant values (k) for both anthocyanins and antioxidant activity. The thermodynamic parameters revealed that the phytochemicals' degradation is a non-spontaneous and endothermic reaction. Furthermore, the inhibitory effect of the extract was investigated against the enzymes affiliated with metabolic syndrome, oxidative stress, and inflammatory process diseases. Thus, we also demonstrated that the red onion skins extract exerted inhibitory activity on α-glucosidase, α-amylase, lipase, and lipoxygenase. Considering the high content of bioactives and various biological properties, the red onion skins extract is suitable for multiple applications.
本研究旨在调查红洋葱皮提取物中植物化学物质的热稳定性和生物活性，红洋葱皮提取物是花青素的丰富来源。通过高效液相色谱法在提取物中鉴定出8种花青素，其中含量最高的是矢车菊素3 - 层链糖苷和矢车菊素3 - （6″-丙二酰-层链糖苷）。该研究还涉及评估花青素在75 - 155°C温度范围内的热降解动力学和抗氧化活性。使用一级动力学模型描述热降解动力学。就热稳定性而言，温度升高导致两种花青素和抗氧化活性的半衰期值（t）降低，降解速率常数（k）升高。热力学参数表明，植物化学物质的降解是一个非自发的吸热反应。此外，研究了该提取物对与代谢综合征、氧化应激和炎症性疾病相关酶的抑制作用。因此，我们还证明了红洋葱皮提取物对α-葡萄糖苷酶、α-淀粉酶、脂肪酶和脂氧合酶具有抑制活性。考虑到生物活性成分的高含量和多种生物学特性，红洋葱皮提取物适用于多种应用。
