Improving the oxidative stability and lengthening the shelf life of DHA algae oil with composite antioxidants.

Based on various antioxidant mechanisms, four kinds of antioxidants including ascorbyl palmitate (AP), vitamin E (VE), phytic acid (PA) and one of the polyphenols (antioxidant of bamboo leaves, tea polyphenol palmitate or tea polyphenols (TP)) were used in combination to improve oxidative stability of docosahexaenoic acid (DHA) algae oil. To achieve the best effect, the formulations and mixture ratios of the antioxidant combinations were optimized. The effects were monitored by peroxide value, thiobarbituric acid-reactive substances, acid value, free radicals, Rancimat induction time and fatty acid composition of DHA algae oil undergoing accelerated storage. Finally, the DHA algae oil containing 80 mg/kg AP, 80 mg/kg VE, 40 mg/kg PA and 80 mg/kg TP had the highest oxidative stability. Furthermore, the shelf life of DHA algae oil containing the optimum composite antioxidant was predicted by using accelerated shelf life testing coupled with Arrhenius model, which was 3.80-fold longer than the control sample.

Mechanism of antioxidant action of natural phenolics on scallop (Argopecten irradians) adductor muscle during drying process.

Lipid hydrolysis and oxidation occurred in Argopecten irradians adductor muscle during hot air drying. Using an in vivo imaging system, we found that antioxidants of bamboo leaves (AOB) could diffuse into the adductor muscle upon marinating. Both tea polyphenols (TP) and AOB efficiently retarded lipid oxidation but had a slight effect on lipid hydrolysis during drying process. The in situ antioxidant mechanisms of AOB as well as TP were revealed, including quenching of free radicals detected by electron spin resonance, chelating metal ions determined by confocal laser scanning microscopy and inhibiting lipoxygenase. Less than 8% of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in AOB and TP marinated adductor muscle were decreased compared to more than 28% decrease in control adductor muscle during the drying process. Overall, these natural antioxidants, TP and AOB, efficiently maintained high nutritive value of adductor muscle, especially, their lipid quality.

Extraction and detailed characterization of phospholipid-enriched oils from six species of edible clams.

Phospholipid (PL)-enriched oils were recovered from six species of edible clams, namely Cyclina sinensis, Mactra chinensis Philippi, Mactra veneriformis Reeve, Meretrix meretrix, Ruditapes phliippinarum and Saxidomus purpurata, using a mixture of ethanol and hexane (1:1, v/v). The oils contained a high proportion of polyunsaturated fatty acids (PUFA) (26.78-45.36% of total FAs), especially eicosapentaenoic acid (EPA) (8.17-10.48% of total FAs) and docosahexaenoic acid (DHA) (7.83-21.34% of total FAs). The oils also contained a high percentage of PL (39.86-74.05% of total lipids). Among PL, phosphatidylcholine (37.40-52.19mol%) and phosphatidylethanolamine (34.74-43.10mol%) were dominant. At least 435, 442, 513, 438, 433 and 437 glycerophospholipid (GP) molecular species were characterized, respectively, in lipids from Cyclina sinensis, Mactra chinensis Philippi, Mactra veneriformis Reeve, Meretrix meretrix, Ruditapes phliippinarum and Saxidomus purpurata. Most of the predominant GP molecular species contained PUFA, mainly EPA and DHA, indicating that clam is a potential resource of PUFA enriched GP.

Effects of long-term intake of Antarctic krill oils on artery blood pressure in spontaneously hypertensive rats.

BACKGROUND: In recent years, there has been a noticeable increase in research on krill oil (KO) for its health benefits. However, the action of KO in lowering blood pressure (BP) has not been studied yet. Therefore the aim of this study was to assess the ability of long-term KO supplementation to lower systolic BP (SBP) in spontaneously hypertensive rats (SHRs) and Sprague Dawley (SD) rats. RESULTS: Compared with the blank control (BC) SHRs administered edible soybean oil, the high-dose (500 mg kg-1 body weight (BW)) KO-supplemented SHRs in the 2nd, 3rd, 4th and 5th weeks following oral administration, the mid-dose (100 mg kg-1 BW) KO-supplemented SHRs in the 4th and 5th weeks following oral administration and the low-dose (20 mg kg-1 BW) KO-supplemented SHRs in the 5th week following oral administration showed significantly lower SBP (P < 0.05). However, supplementation of KO had no significant effect on the SBP of healthy SD rats. Meanwhile, 5 weeks of KO administration significantly increased the serum levels of nitric oxide (NO) and total NO synthase of SHRs (P < 0.05). CONCLUSION: KO has an antihypertensive effect in SHRs that is associated with an NO-related mechanism. © 2016 Society of Chemical Industry.