Dan Xie

Bayberry ( Myrica rubra Sieb. et Zucc.) kernel is a by‐products of bayberry processing and are rich in oil. This study investigates the effects of different processing methods on bayberry kernel oil (BKO) yield, including cold pressing (CP), direct solvent ( n ‐hexane) extraction, ultrasound‐assisted n ‐hexane extraction (UAE), steam explosion pretreatment to assist n ‐hexane extraction, aqueous enzyme extraction, and supercritical fluid extraction (SFE). The acid value, peroxide value, fatty acid composition, bioactive components content, and the antioxidant activity of the extracted BKO with six methods were compared. The results showed that the oil yield of bayberry kernel extracted by different methods was between 30.95% and 49.49%, and the oil yield of UAE was the highest. BKO samples extracted by different methods had lower acid value (0.39–0.59 mg KOH/g) and peroxide value (3.97–5.84 meq O ₂ /kg), and were rich in unsaturated fatty acids (>85%), mainly including oleic (46.9%–47.9%) and linoleics (37.0%–39.5%). Meanwhile, BKO contained phytosterols (384.67–597.14 mg/100 g) and tocopherols (632.09–1227.62 µg/100 g), which was positively correlated with antioxidant activity. The volatile organic compounds (VOCs) of BKO varied on extraction methods. BKO extracted by CP and SFE showed more VOCs (25 in CP‐BKO, 26 in SFE‐BKO). The representative VOCs in BKO are alcohols and esters. The results provide references for further processing of BKO.

Antarctic krill oil is an emerging marine lipid and expected to be a potential functional food due to its diverse nutrients, such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), phospholipids, astaxanthin and tocopherols. Although krill oil has been previously proved to have anti-inflammatory activity, there is little information about the relationship between its chemical compositions and anti-inflammatory activity. In this study, the RAW264.7 macrophages model was used to elucidate and compare the anti-inflammatory potential of different krill lipid fractions: KLF-A, KLF-H and KLF-E, which have increasing phospholipids, EPA and DHA contents but decreasing astaxanthin and tocopherols levels. Results showed that all the krill lipid fractions alleviated the inflammatory reaction by inhibition of production of nitric oxide (NO), release of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 and gene expression of proinflammatory mediators including TNF-α, IL-1β, IL-6, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). In addition, KLF-E with the highest phospholipids, EPA and DHA contents showed the strongest inhibition effect on the LPS-induced proinflammatory mediator release and their gene expressions. The results would be helpful to provide powerful insights into the underlying anti-inflammatory mechanism of krill lipid and guiding the production of krill oil products with tailor-made anti-inflammatory activity.

Antarctic krill ( Euphausia superba ) oil has been receiving increasing attention due to its nutritional and functional potentials. However, its application as a novel food ingredient has not yet been fully explored. This review summarizes the chemical composition, extraction technologies, potential health benefits, and current applications of krill oil, with the aim of providing suggestions for its exploitation. Krill oil is a unique lipid consisting of diverse lipid classes and is characterized by a high concentration (39.29% to 80.69%) of phospholipids (PLs) associated with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). It also contains considerable amounts of bioactive minor components such as astaxanthin, sterols, tocopherols, vitamin A, flavonoids, and minerals. The current technologies used in krill oil production are solvent extraction, nonsolvent extraction, super/subcritical fluid extraction, and enzyme‐assisted pretreatment extraction, which all greatly influence the yield and quality of the end‐product. In addition, krill oil has been documented to have various health benefits, including anti‐inflammatory effects, cardiovascular disease (CVD) prevention, women's health, neuroprotection, and anticancer activities. Although krill oil products used for dietary supplements have been commercially available, few studies have attempted to explore the underlying molecular mechanisms to elucidate how exactly the krill oil exerts different biological activities. Further studies should focus on this to improve the development of krill oil products for human consumption.