The transfer of natural Rhodamine B contamination from raw paprika fruit to capsicum oleoresin during the extraction process.

Occurrence of Rhodamine B (RhB) contamination in paprika caused by agricultural materials during the vegetation process has been reported. It may transfer during the process of active compounds extraction, and eventually exist in final products. Herein, the re-distribution of RhB during the extraction process was assessed in terms of RhB contents, as well as mass, color value and capsaicinoids yield of each process. Results revealed that natural RhB contamination at 0.55-1.11µg/kg originated from raw paprika fruit then transferred with the extraction proceeded. About 95.5% of RhB was found in red oleoresin. After separation of red oleoresin, 91.6% of RhB was remained in capsicum oleoresin, only 3.7% in paprika red. These results were consistent with total capsaicinoids recovery of each product. The RhB levels in edible capsicum oleoresin in our present study at 0.01-0.34µg/kg did not exceed the legal limits established by the European Union.

Simultaneous determination of four water-soluble vitamins in fortified infant foods by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry.

A novel ultra-performance liquid chromatography electrospray ionization tandem triple quadrupole mass spectrometry method for the simultaneous determination of four water-soluble vitamins, including vitamin B5 (VB5), vitamin B8 (VB8), vitamin B9 (VB9), and vitamin B12 (VB12) in fortified infant foods is developed and validated. A reverse phase UPLC separation system consisting of a Waters ACQUITY UPLC BEH C-18 column (2.1 mm x 100 mm i.d., 1.7 microm) and a binary gradient acetonitrile-water mobile phase is applied for the separation of the four water-soluble vitamins. Formic acid is spiked into the mobile phase to enhance the ionization efficiency. Tandem MS-MS analysis is performed in multi-reaction monitoring mode (MRM). Product-ion traces at m/z 220.1 --> 89.9 for VB5, 245.1 --> 227.1 for VB8, 442.3 --> 295.2 for VB9, and 678.9 --> 147.0 for VB12 are used for quantitation of the corresponding vitamins, and traces at m/z 455.5 --> 308.0 are used for methotrexate (internal standard). Limits of quantitation (LOQs) are 0.016, 0.090, 0.020, and 0.019 microg/L for VB5, VB8, VB9, and VB12, respectively. Intra- and inter-day precisions for the determination of the four vitamins are better than 6.84% and 12.26% in relative standard deviations, and recoveries for the four vitamins are in the range of 86.0~101.5%. The developed approach is applied for the determination of the trace amounts of the vitamins in fortified milk powers and fortified rice powers.

Determination of flavone C-glucosides in antioxidant of bamboo leaves (AOB) fortified foods by reversed-phase high-performance liquid chromatography with ultraviolet diode array detection.

Reversed-phase high-performance liquid chromatography (RP-HPLC) with ultraviolet diode array detection (UV-DAD) was used for the simultaneous determination of four flavone C-glucosides, i.e. orientin, homoorientin, vitexin and isovitexin in several food systems fortified by the antioxidant of bamboo leaves (AOB), such as high temperature sterilized milk, sunflower seed oil and extruded rice cake for the first time. The method included extraction of flavone C-glucosides from AOB-fortified foods by methanol aqueous solution, deproteinating with saturated lead acetate solution and potassium oxalate, defatting with n-hexane and clean-up by solid-phase extraction (SPE) with Phenomenex C18 cartridges. Analytes were separated with Luna C18 5 microm 250mm x 4.6mm column using acetonitrile and 1% (v/v) acetic acid (pH 3.0) as mobile phase. Good results were obtained with respect to repeatability (relative standard deviation (RSD)< 2.2%) and recovery (81.4-91.8%) which fulfilled the requirements defined by European Union (EU) legislation. The total amounts of four flavone C-glucosides were 12.56 microg/100 mL, 881.08 microg/100 mL and 1420.83 microg/100 g dry weight in AOB-fortified sterilized milk, sunflower seed oil and extruded rice cake, respectively. The method was successfully applied to the analysis of flavone C-glucosides in AOB-fortified samples. The optimized procedure could also be referenced for the separation of flavone C-glucosides in other fortified foodstuffs.