Results of the BfR MEAL Study: Highest levels of retinol found in animal livers and of β–carotene in yellow-orange and green leafy vegetables

Vitamin A concentration in bovine liver and milk does not only depend on characteristics of the farming system

The study examined the vitamin A status in commercially managed suckler cows and lactating dairy cows and identified primary influencing factors. Liver retinyl ester concentrations were higher in multiparous than primiparous cows (p < 0.01). Pasture availability was associated with higher β-carotene concentrations (p < 0.001). In dairy cows, pasture access during the dry period did not affect any of the parameters assayed. β-Carotene and retinol in milk increased with parity. No vitamin A deficiency or hypervitaminosis A was detected. Liver and milk retinol and retinyl ester concentrations that were analysed in the present study and data from a recent German total diet study were used to estimate the exposure to preformed vitamin A in vulnerable groups (children, 0.5-5 years). 95th percentiles of preformed vitamin A intake do not exceed tolerable upper intake levels in individuals between 1 year and 5 years, but in infants 6 to 12 months of age.

Levels of naturally occurring radionuclides in foods from the first German total diet study

Although natural radionuclides are always present in foods, information about the levels is scarce. The diet-related exposure to radiation is, however, dependent on the radionuclide content of respective food items. In this study, the levels of the naturally occurring radionuclides lead-210 (Pb-210), uranium-234 (U-234), uranium-238 (U-238), radium-226 (Ra-226) and radium-228 (Ra-228) were investigated in over 200 foods as part of the first German total diet study. Radioanalytical techniques and measurements were applied for determination. The natural radionuclide activity concentrations obtained were generally low compared to international data compilations. Together, Ra-228 and Ra-226 mostly dominated the levels of activity concentrations. Of all Ra-226, Ra-228 and Pb-210 results, between 1 % and 19 % exceeded the International Atomic Energy Agency (IAEA) guidance level for food products of 0.1 Bq/kg or 1 Bq/kg. The received activity levels for both U-234 and U-238 were found to be below the suggested IAEA guidance level of 10 Bq/kg. The radionuclide activity ratios of Ra-226/Ra-228, U-234/U-238 and Pb-210/Ra-226 of the foods were examined as well. In particular, it was found that the average Ra-226/Ra-228 ratio in all main food groups was substantially lower than the average Ra-226/Ra-228 ratio in soils. An isotope dependent transfer of Ra-226 and Ra-228 from soil to plants and foods is suggested to explain the difference. The obtained data set will be a valuable contribution to international data collections and thus help to a better understanding of the public exposure to natural radionuclides from the food consumption in the future.

Germany's first Total Diet Study - Occurrence of non-dioxin-like polychlorinated biphenyls and polybrominated diphenyl ethers in foods

The occurrence of persistent organic pollutants like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in food represents a public health concern. The BfR MEAL Study was initiated to generate a comprehensive data base of occurrence data for chemicals in the most consumed foods in Germany. Non-dioxin-like PCBs (NDL-PCBs) and PBDEs were analysed in 300 foods, purchased and prepared representatively for the eating behaviour of the population in Germany. Highest levels of NDL-PCBs and PBDEs were detected in spiny dogfish, cod liver, herring, and eel. High NDL-PCB and PBDE levels were observed in other oily fish, wild boar meat, sheep liver, and high-fat dairy products. The comparison of food from conventional and organic production revealed higher NDL-PCB values in the food group 'meat and meat products' if produced organically. Occurrence data of this study will improve future dietary exposure and risk assessments in Germany.

How long can you store vitamins? Stability of tocopherols and tocotrienol during different storage conditions in broccoli and blueberries

Differences between the stability of α-, β-, γ-, and δ-tocopherol as well α-tocotrienol stored at -20 °C and -80 °C were studied in broccoli and blueberry samples. Before storage up to 28 days, they underwent different initializing processes such as freezing quickly with liquid nitrogen and freeze-drying, followed by homogenization. While α-tocopherol levels in blueberries did not significantly differ, levels in broccoli were substantially higher after homogenization of freeze-dried samples compared to fresh broccoli samples. This might be caused by higher extractability of α-tocopherol from the changed cell structure. Storage of fresh broccoli samples at -20 °C led to decreasing α-tocopherol levels. Nevertheless, the deviation between freeze-dried samples to the initial fresh samples and fresh samples frozen with liquid nitrogen stored at -20 °C for 7 days were in the same order of magnitude. In conclusion, storage up to 7 days for vitamin relevant samples before analysis seemed to be justifiable.

A comprehensive analysis of the chemical composition of Fraxinus mandshurica roots based on HPLC-DAD-MS, GC-MS and UPLC-ESI-Q-TOF-MS

Fraxinus mandshurica is widely distributed around the world, which has significant economic value and pharmacological effects. However, its roots are often overlooked during processing and use. In this study, the preliminary identification of chemical components in F. mandshurica roots was carried out using ultra-performance liquid chromatography coupled with electrospray quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOF-MS), and a total of 37 characteristic components were identified, including 13 secoiridoids, 7 lignans, 6 coumarins, 4 flavonoids, 4 phenylethanols, 1 terpenoid and 2 other compounds. Meanwhile, to evaluate the 6 lignans content of F. mandshurica roots, the identification, quantitation analysis and methodological validation were performed by high-performance liquid chromatography with diode array detection mass spectrometry (HPLC-DAD-MS), which showed that the concentration range of standard compounds was 0.5-1000 μg/mL. The standard curve correlation coefficients (R²) were all greater than 0.9991, indicating that the linearity of the fitted curves was good. The highest lignan content in F. mandshurica roots was olivil (461.11 μg/g) and the lowest in buddlenol E (11.14 μg/g), and the total lignan content was 764.63 μg/g. The relative standard deviations (RSD, %) of both intra-day and inter-day precision were less than 1.95%. The RSD (%) of the reproducibility and stability experiments was less than 2.91%. The spiked recoveries of the samples were in the range of 98.29-102.62%, and the RSD (%) was in the range of 0.43-1.73, indicating that the method has high accuracy. In addition, a total of 20 volatile components in F. mandshurica roots were identified and quantified by gas chromatography-mass spectrometer (GC-MS) in this study, which laid a solid foundation for the comprehensive development and utilization of F. mandshurica resources.

Whey Protein Isolate-Mesona chinensis Polysaccharide Conjugate: Characterization and Its Applications in O/W Emulsions

Mesona chinensis polysaccharide (MCP), a common thickener, stabilizer and gelling agent in food and pharmaceuticals, also has antioxidant, immunomodulatory and hypoglycemic properties. Whey protein isolate (WPI)-MCP conjugate was prepared and used as a stabilizer for O/W emulsion in this study. FT-IR and surface hydrophobicity results showed there could exist interactions between -COO- in MCP and -NH³⁺ in WPI, and hydrogen bonding may be involved in the covalent binding process. The red-shifted peaks in the FT-IR spectra suggested the formation of WPI-MCP conjugate, and MCP may be bound to the hydrophobic area of WPI with decreasing surface hydrophobicity. According to chemical bond measurement, hydrophobic interaction, hydrogen bond and disulfide bond played the main role in the formation process of WPI-MCP conjugate. According to morphological analysis, the O/W emulsion formed by WPI-MCP had a larger size than the emulsion formed by WPI. The conjugation of MCP with WPI improved the apparent viscosity and gel structure of emulsions, which was concentration-dependent. The oxidative stability of the WPI-MCP emulsion was higher than that of the WPI emulsion. However, the protection effect of WPI-MCP emulsion on β-carotene still needs to be further improved.