Search

In order to obtain peptide fractions, duck liver proteins were recovered by isoelectric precipitation, and then hydrolyzed simultaneously by alcalase and flavorzyme. The molecular mass distribution of the hydrolysate was determined by using a gel permeation chromatography (GPC) system followed by fractionation using a combination of gel filtration chromatography (GFC) and reversed phase-high performance liquid chromatography (RP-HPLC). Ten novel peptides with molecular mass less than 1 300 Da were identified from the subfraction with high inhibitory effect on cytokine release from macrophages using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The anti-inflammatory activity of the synthetic peptides was tested in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. Peptides LVYPFPGPI and VIESPPEI inhibited the release of NO from inflammatory cells in a dose-dependent manner, with inhibition percentages of 48.24% and 56.32% at the concentration of 100 μg/mL, respectively. VIESPPEI at the concentration of 100 μg/mL inhibited TNF-α release by 42.48%. Notably, IDVSPDSPDHY showed the strongest ability to inhibit the release of IL-6, with an inhibition percentage of 27.04% at the concentration of 25 μg/mL. This study may provide new ideas for the high-valued comprehensive utilization of duck by-products and their application in safe treatment of inflammation.

To evaluate the residual level of fungicides and dietary exposure risk of Chinese chives in production bases and segments like markets in Zhejiang Province. The collection period was mainly from December 2020 to January 2021, and from August 2021 to November 2021. Thirty-nine fungicides in 213 Chinese chives samples collected in Zhejiang Province over the two consecutive years were detected and analyzed, and the risk of acute and chronic dietary exposure to the detected fungicides was assessed. There were 19 fungicides were detected, and the total detection rate was 48.83% (104 out of 213), among which the detection rates of procymidone (15.02%), carbendazim (13.15%), boscalid (13.15%), dimethomorph (11.74%), pyraclostrobin (11.27%) and chlorothalonil (10.80%) were relatively high. The samples with two or more pesticide residues accounted for 25.82% of the total samples (55 out of 213). The residue of pyrimethanil in one sample exceeded the maximum residue limit for bulb vegetables (3 mg/kg) set by the Ministry of Agriculture and Rural Affairs, with the over-limit rate being 0.47%, and the sample qualified rate reaching 99.53%. According to the current standard for procymidone GB 2763.1-2022 (5 mg/kg), none of the samples had the residue exceeding the standard. According to the original standard GB 2763-2021 (0.20 mg/kg), and the over-limit rate was 7.04% (15 out of 213). The acute and chronic risk ranges were 0.004%~5.546% and 0.000%~9.654%,respectively, both of which were lower than 1, thus the intake risk was at an acceptable level. The situation of pesticide residues in Chinese chivesis from Zhejiang Province was relatively serious, thus the management of the use of pesticides should be strengthened to ensure the safety of Chinese chives consumption. [ABSTRACT FROM AUTHOR]

The effects of Lactobacillus acidophilus CICC6074 (LA), Limosilactobacillus reuteri WQ-Y1 (LR) and Lactiplantibacillus plantarum A3 (LP) on calcium release and metabolite composition during the fermentation of chicken bone paste were studied using chicken bone as raw materials. The growth characteristics of lactic acid bacteria (LAB) strains, pH changes, total acidity variations, calcium distribution and calcium-to-phosphorus ratio, composition and content of metabolites were investigated to reveal the effect of the growth of LAB on calcium release during the fermentation of chicken bone paste. Principal component analysis (PCA), correlation analysis, and KEGG metabolic pathway analysis were further employed to identify the key metabolic pathways during the fermentation of chicken bone paste. The results showed that, LA, LR and LP strains were able to effectively utilize chicken bone paste for growth and proliferation, and the maximum viable cell count was observed at 30 h during the fermentation processing. The total acidity contents of LA, LP and LR groups were 5.60, 3.76, and 3.75 g/L respectively, significantly higher total acidity content was shown in LA group compared to other treatment groups (P<0.05). Calcium release analysis revealed that the total calcium content increased from 181.33 mg/kg of control group to 1176.67 mg/kg of LR, 1310.00 mg/kg of LP, and 1916.67 mg/kg of LA, respectively. The free calcium content of LA, LP and LR groups was 40.60, 50.19, and 74.62 fold-time higher than that of control group, and the free calcium content of LA group was significantly higher compared to LP and LR groups (P<0.05). X-ray diffraction and infrared spectroscopy results indicated that hydroxyapatite of bone paste mainly existed in an amorphous form. The intensity of characteristic peaks of hydroxyapatite at 2926 and 1050 cm-1 significantly decreased among LR, LP and LA groups compared to control group. LC-MS/MS analysis demonstrated that 37 metabolites were identified in the fermented bone paste. Principal Component Analysis (PCA) and correlation analysis revealed that lactic acid, pyruvate, sucrose, L-serine, and 5'-CMP were the key metabolites of fermented bone paste. KEGG metabolic pathway analysis indicated that pyrimidine metabolism, arginine and proline metabolism, glycolysis, pyruvate metabolism, taurine and hypotaurine metabolism, and tricarboxylic acid (TCA) cycle were the main metabolic pathways associated with lactic acid bacteria growth and calcium release during the fermentation of bone paste. [ABSTRACT FROM AUTHOR]