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A rapid high-performance liquid chromatography (HPLC) protocol for the determination of amino acids with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization was successfully developed for assessing amino acid levels in six species of representative commercial bee pollen. Based on a poroshell column, a favorable chromatographic separation of seventeen amino acids was achieved in approximately 10 min with satisfactory resolution. The LOD and LOQ of this method were less than 0.034 µg/mL and 0.232 µg/mL, and the intra- and inter-day RSDs ranged between 0.86-5.28 % and 3.21-6.50 %, respectively. The matrix effect (ME) ranged from -8 to 3, implying that the matrix effect was not significant. Under the optimum conditions, the established method was adopted to determine amino acids in six types of bee pollens. The results showed that the total amino acid content ranged from 151.94 mg/g (Rosa rugosa) to 214.52 mg/g (Leonurus artemisia) in the six bee pollen species. Notably, proline (Pro), valine (Val), leucine (Leu), and phenylalanine (Phe) were abundant in the majority of samples. To identify the suspicious samples, principal component analysis (PCA) was performed, and each type of bee pollen was differentiated. Results showed that, in the market, the qualification rate of RR was 100 %, but that of NN was merely 62.5 %, revealing that a few of them were counterfeit. This method offers advantages such as high speed, low cost, and outstanding performance.

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DPPH• scavenging peptides (<3kDa) from underutilized Dunaliella salina protein were obtained by the following successive treatment, i.e., ultrasound extraction, simulated in vitro gastrointestinal digestion hydrolyzation, and membrane ultrafiltration classification. The optimal condition for ultrasound-assisted extraction was an ultrasound wave with 800 W of power treating a mixture of 60 mL of 1.0 mol L-1 NaOH and 2 g algae powder for 15 min. A high correlation (r=0.8146) between DPPH• scavenging activity and yield of the intact peptides showed their antioxidant capacity. Simulated in vitro digestion assay resulted in excellent DPPH• scavenging activity of the total peptide, amounting to (86.5 ± 10.1)%, comparing with the nondigestion samples at (46.8 ± 6.5)%. After fractionation, the 500-1000 Da fraction exhibited the highest DPPH• scavenging activity (81.2 ± 4.0)%, increasing 1.5 times due to digestion. Then, the 500-1000 Da fraction was analyzed by RPLC-Q Exactive HF mass spectrometer, and 4 novel peptides, i.e., Ile-Leu-Thr-Lys-Ala-Ala-Ile-Glu-Gly-Lys, Ile-Ile-Tyr-Phe-Gln-Gly-Lys, Asn-Asp-Pro-Ser-Thr-Val-Lys, and Thr-Val-Arg-Pro-Pro-Gln-Arg, were identified. From these amino acid sequences, hydrophobic residues accounted for 56%, which indicated their high antioxidant property. The results indicated that underutilized protein of Dunaliella salina could be a potential source of antioxidative peptides through simulated in vitro gastrointestinal digestion.

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High plasma level of HDL-cholesterol (HDL-C) has been consistently associated with a decreased risk of atherosclerosis (AS); thus, HDL-C is considered to be an antiatherogenic lipoprotein. The development of novel therapies to enhance the atheroprotective properties of HDL may have the possibility of further reducing the residual AS risk. Reverse cholesterol transport (RCT) is believed to be a primary atheroprotective activity of HDL, which has been shown to promote the efflux of excess cholesterol from macrophage-derived foam cells via ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), and scavenger receptor class B type I (SR-BI) and then transport it back to the liver for excretion into bile and eventually into the feces. In the current study, we investigated the effects of astaxanthin on RCT and AS progression in mice. The results showed that short- and long-term supplementation of astaxanthin promote RCT in C57BL/6J and ApoE-/- mice, respectively. Moreover, astaxanthin can relieve the plaque area of the aortic sinus and aortic cholesterol in mice. These findings suggest that astaxanthin is beneficial for boosting RCT and preventing the development of AS.

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Slimming supplements were popularly sold online driven by the increasement of obesity and the development of social networking platform. However, events of drug abuse in slimming supplements were also frequently reported. In this study, a graphene tip solid-phase extraction (Gtip SPE) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established for determining fenfluramine, phenolphthalein, bumetanide, and sibutramine in slimming supplements. It was validated in terms of linearity (0.9985-0.9995), LOD (1.8ngmL-1), LOQ (5.6ngmL-1), intra-day precision (<5.1%), inter-day precision (<7.3%), and recovery (82.9-95.2%). Sibutramine is the most commonly used drug, which was detected in Bihais, Galong, and Aolist, with content 12.4, 3.6, 20.3mgg-1, respectively. Phenolphthalein was also found with content lower than 5.2mgg-1. The successful application of Gtip SPE and UPLC-MS/MS method indicated its advantage in analyzing low level of contaminates resulted from violation of regulation.

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BACKGROUND: γ-Glutamyltranspeptidase (GGT; EC 2.3.2.2) is a widely distributed enzyme that is of interest in the food industry. In this study the effects of pH and dissolved oxygen (DO) on GGT synthesis from Bacillus subtilis SK 11.004 were investigated. RESULTS: GGT production increased to 0.5 U mL⁻¹ when the pH value was controlled at 6.5. The control of a single DO level revealed that the highest specific growth rate (3.42 h⁻¹) and GGT production rate (0.40 U g⁻¹ mL⁻¹) were obtained at DO levels of 40 and 10% respectively. To satisfy the different oxygen demands at different stages of cell growth and GGT synthesis, a stage DO level control strategy was designed as follows: 40% from 0 to 4 h, 30% from 4 to 6 h and 10% from 6 to 18 h. Furthermore, the maximum biomass (2.27 g L⁻¹) and GGT production (3.05 U mL⁻¹) could be obtained using a fermentation strategy combining a constant pH value with stage DO level control. CONCLUSION: The proposed fermentation strategy resulted in a 13.7-fold increase in GGT production. This finding should be of great importance for the industrial production of GGT.

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