Jiang-Ning Hu

Evaluating and Predicting the Oxidative Stability of Vegetable Oils with Different Fatty Acid Compositions

The aim of this research was to evaluate the oxidative stabilities and qualities of different vegetable oils (almond, blend 1-8, camellia, corn, palm, peanut, rapeseed, sesame, soybean, sunflower, and zanthoxylum oil) based on peroxide value (PV), vitamin E content, free fatty acid, and fatty acid composition. The vegetable oils with different initial fatty acid compositions were studied under accelerated oxidation condition. It showed that PV and n-3 polyunsaturated fatty acid (PUFA) changed significantly during 21 d accelerated oxidation storage. Based on the changes of PV and fatty acid composition during the oxidation process, mathematical models were hypothesized and the models were simulated by Matlab to generate the proposed equations. These equations were established on the basis of the different PUFA contents as 10% to 28%, 28% to 46%, and 46% to 64%, respectively. The simulated models were proven to be validated and valuable for assessing the degree of oxidation and predicting the shelf life of vegetable oils.

Stereospecific Analysis of Triacylglycerol and Phospholipid Fractions of Five Wild Freshwater Fish from Poyang Lake

The fatty acids (FA) compositions and positional distributions in triacylglycerols (TAG) and phospholipids (PL) of five wild freshwater fish (Squaliobarbus curriculus, Erythroculter ilishaeformis, Pseudobagrus fulvidraco, Bostrichthys sinensis, and Siniperca kneri Garman) from Poyang Lake (the largest freshwater lake of China) were studied. For TAG, S. kneri German had the highest content (13.59%) of n - 3 polyunsaturated fatty acids (PUFA) and E. ilishaeformis had the lowest ratio of (n - 6)/(n - 3) (0.65). PL had a high content of PUFA, which declined in the order of phosphatidylethanolamine (PE) > phosphatidylcholine (PC) > TAG. 9c11t-18:2 accounted for 6.38-50.77% of total conjugated linoleic acids (CLA). The highest level of odd-branched chain fatty acids (OBCFA) was 26.7% in B. sinensis. The study revealed that the distribution of FA among the sn positions was not random: monounsaturated fatty acids (MUFA) and PUFA preferred positions 1 and 3 and saturated fatty acids (SFA) position 2 of TAG, while SFA and MUFA predominated over sn-1-PL and PUFA over sn-2-PL.

Erythrocyte membrane trans-fatty acid index is positively associated with a 10-year CHD risk probability.

Industry-generated trans-fatty acids (TFA) are detrimental to risk of CHD, but ruminant-originated TFA have been reported as neutral or equivocal. Therefore, the total TFA amount should not be the only factor considered when measuring the effects of TFA. In the present study, we addressed whether a version of the TFA index that unifies the effects of different TFA isomers into one equation could be used to reflect CHD risk probability (RP). The present cross-sectional study involved 2713 individuals divided into four groups that represented different pathological severities and potential risks of CHD: acute coronary syndrome (ACS, n 581); chronic coronary artery disease (CCAD, n 631); high-risk population (HRP, n 659); healthy volunteers (HV, n 842). A 10-year CHD RP was calculated. Meanwhile, the equation of the TFA index was derived using five TFA isomers (trans-16 : 1n-7, trans-16 : 1n-9, trans-18 : 1n-7, trans-18 : 1n-9 and trans-18 : 2n-6n-9), which were detected in the whole blood, serum and erythrocyte membranes of each subject. The TFA index and the 10-year CHD RP were compared by linear models. It was shown that only in the erythrocyte membrane, the TFA isomers were significantly different between the groups. In the ACS group, industry-generated TFA (trans-16 : 1n-9, trans-18 : 1n-9 and trans-18 : 2n-6n-9) were the highest, whereas ruminant-originated TFA (trans-16 : 1n-7 and trans-18 : 1n-7), which manifested an inverse relationship with CHD, were the lowest, and vice versa in the HV group. The TFA index decreased progressively from 7·12 to 5·06, 3·11 and 1·92 in the ACS, CCAD, HRP and HV groups, respectively. The erythrocyte membrane TFA index was positively associated with the 10-year CHD RP (R 2 0·9981) and manifested a strong linear correlation, which might reflect the true pathological severity of CHD.

Oxidation and antioxidative effects of rosemary extract and catechin on enzymatically modified lipids containing different total and positional fatty acid compositions

The oxidative stabilities of enzymatic modified lipids (EMLs) were studied using pine nut oil (PN) and palm stearin (PS) as substrates (w/w, 40:60; 30:70) vs. a physical blend (PB). The amount of pinolenic acid (PLA) at the sn-2 position in EML was increased to 5.5% compared to 0.8% in PB. The acid, peroxide, p-anisidine, and TBARS values were used to measure the oxidative stability of EML and PB. After 30 days of oxidation, only 1.5 and 0.7% of total PLA at sn-2 position PLA were detected in EML of PN:PS 40:60 and PN:PS 40:60, respectively. EMLs were more vulnerable to oxidization than PB. Different concentrations of rosemary (1,000 and 2,000 mg/kg) and catetchin (400 and 800 mg/kg) were added to EMLs to reduce the oxidation level. Results indicated that these two antioxidants deterred the extent of oxidation in EMLs.

Separation of Phospholipids from Hen Egg Yolk by Short Packed Silica Gel Column Chromatography

Short packed silica gel column chromatography has been performed to optimize the production of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) from hen egg yolk with very low or no toxic solvents. The effects of silica type, sample loading amount, dimension of the glass chromatotube, and mobile phase compositions were investigated and high separation efficiency was achieved: gradient elution as 200 mL ethanol followed by 300 mL 95% ethanol to fractionate PE and PC after neutral lipids (NL) removed by 120 mL ethyl acetate, 40 mm silica gel (54 to 74 μm) bed height of the chromatotube with 22 mm inner dia (ID), and 0.25 g sample loading amount. By this procedure, 3.69 g PE and 2.88 g PC per 100 g egg yolk lipids were obtained, respectively. The refined PE and PC were identified by high-performance liquid chromatography/ultraviolet detector (HPLC-UV) with purity over 96%. The fatty acids in egg yolk revealed that PE and PC characterized higher ratios of n- 6/n- 3 (PE, 7.41; PC, 8.99). 18:2 n- 6 of PC (15.21%) predominated over PE (10.29%), whereas the level of 20:4 n- 6 of PC (8.78%) was lower than PE (15.67%).

Investigation of Lipid Metabolism by a New Structured Lipid with Medium- and Long-Chain Triacylglycerols from Cinnamomum camphora Seed Oil in Healthy C57BL/6J Mice

In the present study, a new structured lipid with medium- and long-chain triacylglycerols (MLCTs) was synthesized from camellia oil (CO) and Cinnamomum camphora seed oil (CCSO) by enzymatic interesterification. Meanwhile, the antiobesity effects of structured lipid were investigated through observing the changes of enzymes related to lipid mobilization in healthy C57BL/6J mice. Results showed that after synthesis, the major triacylgeride (TAG) species of intesterificated product changed to LaCC/CLaC (12.6 ± 0.46%), LaCO/LCL (21.7 ± 0.76%), CCO/LaCL (14.2 ± 0.55%), COO/OCO (10.8 ± 0.43%), and OOO (18.6 ± 0.64%). Through second-stage molecular distillation, the purity of interesterified product (MLCT) achieved 95.6%. Later, male C57BL/6J mice were applied to study whether the new structured lipid with MLCT has the efficacy of preventing the formation of obesity or not. After feeding with different diets for 6 weeks, MLCTs could reduce body weight and fat deposition in adipose tissue, lower plasma triacylglycerols (TG) (0.89 ± 0.16 mmol/L), plasma total cholesterol (TC) (4.03 ± 0.08 mmol/L), and hepatic lipids (382 ± 34.2 mg/mice) by 28.8%, 16.0%, and 30.5%, respectively, when compared to the control 2 group. This was also accompanied by increasing fecal lipids (113%) and the level of enzymes including cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), hormone-sensitive lipase (HSL), and adipose triglyceride lipase (ATGL) related to lipid mobilization in MLCT group. From the results, it can be concluded that MLCT reduced body fat deposition probably by modulating enzymes related to lipid mobilization in C57BL/6J mice.