Cong Xin-Yuan, Miao Jun-Kui, Zhang Hui-Zhen, Sun Wei-Hong, Xing Li-Hong, Sun Li-Rui, Zu Lu, Gao Yan, Leng Kai-Liang
School of Public Health Qingdao, Qingdao University, Qingdao 266071, China.
Yellow Sea Fishery Research Institute, Chinese Academy of Fishery Sciences, Key Laboratory of Sustainable Development of Polar Fishery, Ministry of Agriculture, 106 Nanjing Road, Qingdao 266071, Shandong, China.
ACS Omega. 2019 Oct 25;4(19):17972-17980. doi: 10.1021/acsomega.9b01294. eCollection 2019 Nov 5.
Antarctic krill () is one of the important bioresources in Antarctic waters, containing many bioactives (e.g., astaxanthin), which have a highly potential value for commercial exploitation. In this study, the effects of processing methods on the content, structural isomers, and composition of astaxanthins (free astaxanthin and astaxanthin esters) were studied. Three drying methods, comprising freeze-drying, microwave drying, and hot-air drying, were used. Free astaxanthin (Ast), astaxanthin monoesters (AM), and astaxanthin diesters (AD) in boiled krill (control) and dried krill were extracted and analyzed using high-resolution mass spectrometry with ultraviolet detection. After the three processes, total astaxanthin loss ranged from 8.6 to 64.9%, and the AM and AD contents ranged from 78.3 to 16.6 and 168.7 to 90.5 μg/g, respectively. Compared to other kinds of astaxanthin esters, astaxanthin esters, which linked to eicosapentaenoic acid and docosahexaenoic acid, as well as the Ast, were more easily degraded, and AM was more susceptible to degradation than AD. All--astaxanthin easily transformed to the 13astaxanthin than to the 9astaxanthin during the drying process, but the proportions of optical isomers changed due to drying by no more than 5%. The results suggested that freeze-drying, low-power microwave drying (≤1 kW), and low-temperature hot-air drying (≤60 °C) are optimal drying methods for ensuring the quality of krill products.
南极磷虾是南极海域重要的生物资源之一，含有许多生物活性物质（如虾青素），具有很高的商业开发价值。本研究考察了加工方法对虾青素（游离虾青素和虾青素酯）含量、结构异构体和组成的影响。采用了三种干燥方法，即冷冻干燥、微波干燥和热风干燥。对煮熟的磷虾（对照）和干燥后的磷虾中的游离虾青素（Ast）、虾青素单酯（AM）和虾青素二酯（AD）进行提取，并使用带紫外检测的高分辨率质谱进行分析。经过这三个过程后，虾青素的总损失率在8.6%至64.9%之间，AM和AD的含量分别在78.3至16.6 μg/g和168.7至90.5 μg/g之间。与其他种类的虾青素酯相比，与二十碳五烯酸和二十二碳六烯酸相连的虾青素酯以及Ast更容易降解，且AM比AD更易降解。在干燥过程中，全反式虾青素比9-顺式虾青素更容易转化为13-顺式虾青素，但光学异构体的比例因干燥而变化不超过5%。结果表明，冷冻干燥、低功率微波干燥（≤1 kW）和低温热风干燥（≤60℃）是确保磷虾产品质量的最佳干燥方法。
