Abstract
In this study, a novel method for obtaining high-quality krill oil from wet Antarctic krill by using subcritical dimethyl ether (SDE) was proposed. A response surface design was used to obtain the best SDE extraction parameters. The optimum extraction efficiency of 93.77 ± 0.92% was obtained at a stirring speed of 1030 rpm, temperature of 47 °C and dynamic extraction time of 90 min. Compared with n-hexane, ethanol, supercritical CO2 and subcritical n-butane extraction, the krill oil extracted by SDE exhibited low peroxide values (1.46 ± 0.26 mmol kg−1), high astaxanthin (218.06 ± 4.74 mg kg−1), phosphatidylcholine (PC) (33.95 ± 0.65%), and phosphatidylethanolamine (PE) (11.67 ± 0.23%) content. Moreover, krill oil extracted by SDE has high levels of EPA (16.38 ± 0.05%) and DHA (7.91 ± 0.07%). SDE extraction proved to be an efficient and safe method for extraction of quality krill oil from wet Antarctic krill, and it could be a promising method for oil extraction in wet food in future.
Highlights
Antarctic krill, one of the largest of eighty-six krill species, mainly inhabit the Southern Ocean.[1]
The extraction efficiency ranged from 84.82% to 94.11%, which indicated that the considerable variation in extraction efficiency depending on different extraction conditions
This work displayed the feasibility of extraction of krill oil from wet Antarctic krill by subcritical dimethyl ether (SDE)
Summary
One of the largest of eighty-six krill species, mainly inhabit the Southern Ocean.[1]. The common methods for extracting krill oil from krill meal mainly include organic solvent extraction, supercritical uid extraction and subcritical uid extraction. The supercritical CO2 extraction has been applied to heatsensitive bioactive compounds extraction. It has some drawbacks as follows: (1) CO2 has lower solubility of polar lipids because of its non-polar nature;[16,17] (2) higher operation cost. To the best of our knowledge, the extraction of Antarctic krill lipid by subcritical nbutane has been reported.[12,18] But subcritical n-butane was not a suitable method for extracting polar lipid from Antarctic krill due to the weaker polarity of butane. Like the abovementioned conventional methods, subcritical n-butane was suitable for extracting krill oil from dried krill meal. The krill meal produced by traditional heat drying methods would destroy the bioactive compounds and deteriorate the quality of 34274 | RSC Adv., 2019, 9, 34274–34282
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