Browsing by Author "Tavanez, Patricia"
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- Cobalamin Levels in Fish and Fortified Milk SubstitutesPublication . Motta, Carla; Moreira, Tiago; Tavanez, Patricia; Castanheira, IsabelObjectives: Natural forms of vitamin B12, methylcobalamin (MeCbl),andhydroxocobalamin(OHCbl)arebioidenticaltotheforms occurringinhumanphysiologyandanimalfoods.However,infortified foods, different vitamers can be present including cyanocobalamin (CNCbl), a synthetic form that can be problematic due to cyanide content.Themaingoalofthisworkistoidentifythedifferentvitamin B12 vitamers (CNCbl, MeCbl, and OHCbl) in fish and in fortified soy milktocharacterizethedifferenttypesofcobalaminspresentinnatural andfortifiedfoods. Methods: Samples of a fish from the Portuguese water coastline (mackerel) and samples of commercial fortified soy milk beverages available on the Portuguese market were collected. Mackerel samples were analyzed raw, after boiling on steam and canned in water. The clean-up was performed by immunoaffinity columns. The different vitamerswereanalyzedinaUHPLCcoupledtoatriplequadrupolemass spectrometerwithelectrosprayionization. Results: In mackerel, the identified vitamers were MeCbl (prevalent form) and OHCbl. The sum of vitamers is in raw fish was 9.2±1.2 µg/100 g, in steamed fish, 8.3±0.6 µg/100 g and in canned fish6,1±0,8µg/100g.Insoymilk,theidentifiedvitamerwasCNCbl, with values between 0.23±0.2 µg/100 mL and 0.75±.3 µg/100 mL. Taking into account the adequate intake for adults (4µ/day), the consumption of 100 g of mackerel represents from 61% (in canned fish) to 97% (in raw fish) of the recommendations. Regarding the soy milk, we observe that values found analytically, are different from the ones reported in the label (0.38 µg/100 mL). Fortified soy milky presents in Portugal a medium consumption of 224 mL/day, in consumers (IAN-AF, 2016). For this population, the consumption of soymilkrepresentsamaximumof44%oftherecommendedadequate intake. Conclusions: Mackerel represents an important source of natural cobalamins,withrecognizedbioavailabilitiesandphysiologicaleffects. Individuals or ethnic groups whose diets exclude or restrict animalbased diets (such as vegans) may be at risk for inadequate nutrient intake.
- Cobalamin Levels in Fish and Fortified Milk SubstitutesPublication . Motta, Carla; Moreira, Tiago; Tavanez, Patricia; Castanheira, IsabelObjectives: Natural forms of vitamin B12, methylcobalamin (MeCbl), and hydroxocobalamin (OHCbl) are bioidentical to the forms occurring in human physiology and animal foods. However, in fortified foods, different vitamers can be present including cyanocobalamin (CNCbl), a synthetic form that can be problematic due to cyanide content. The main goal of this work is to identify the different vitamin B12 vitamers (CNCbl, MeCbl, and OHCbl) in fish and in fortified soy milk to characterize the different types of cobalamins present in natural and fortified foods.
- Desenvolvimento de um método para determinação de Vitamina B12 em alimentos, por cromatografia líquida acoplada a espectrometria de massas (LC-MS/MS)Publication . Tavanez, Patricia; Leitão, Ana Lúcia Monteiro Durão; Motta, Carla Alexandra Fino Alberto daThe aim of the present work was focused on the otimization of the extraction and chromatographic method used with the purpose of determining the B12 vitamin content in fortified samples (soy based vegetable drinks) and natural (raw mackerel). The immunoaffinity columns use as the clean-up method contributed to the optimization of the method and, consequently, to the determination of the diferente vitamers in the different matrices. In the fortified soy based vegetable drinks, simpler matrices, it was possible to identify the present cyanocobalamin, with levels estimated between 0,25 and 0,66 μg/100 mL, values very similar to those obtained by ultracentrifugation. In the mackerel samples, more complex matrices, it was tested two extraction methods: with and without sodium cyanide, in order to determine the different natural forms of vitamin B12 as well as their total content. The obtained results show that hydroxocobalamin is the major present form in this natural sample and it represents 35 to 58% of the total vitamin B12 content, unlike cyanocobalamin which is found in residual levels. The total content of vitamin B12, express by content of cyanocobalamin, the average value is estimated to be 13,9 μg/100 mL. Some parameters were also evaluated for the validation of the method. Linearity was verified for the concentration range of the calibration curves under study and, although the homogeneity of variances was not verified, the analysis of reference materials allowed to evaluate the accuracy, having obtained a z-score < 2. The development of this work thus represents a contribution to the optimization and development of the method, and the results obtained can be considered, although it is necessary to carry out more tests, promising.