Influência do tempo de armazenamento sobre a concentração de alfa-tocoferol e gama-tocoferol em óleos vegetais / Influence of the storage time on the concentration of alpha-tocopherol and gamma-tocopherol in vegetable oils

O alfa- e o gama-tocoferol estão entre os homólogos da vitamina E, que possui importante papel como antioxidante. As fontes dietéticas mais ricas em vitamina E são os óleos vegetais. Este trabalho avaliou os níveis de alfa- e gama-tocoferol nos óleos de canola, girassol, milho e soja, e averiguou sua variação com o tempo de armazenamento. Os óleos vegetais foram adquiridos nos supermercados da cidade de Natal/RN, e mantidos sob temperatura ambiente e ao abrigo da luz. As análises foram realizadas em diferentes momentos durante o armazenamento (tempo 0 e após 30, 60 e 90 dias). Cromatografia líquida de alta eficiência (CLAE) foi usada para determinar as concentrações dos analitos. A análise estatística foi realizada utilizando-se o teste de variância (ANOVA) e as diferenças foram consideradas estatisticamente significativas quando p < 0,05. Ao final do tempo de armazenamento (90 dias) foi verificada diminuição significativa nos níveis de alfa- e gama-tocoferolde 38,7 % e 36,0 %, no óleo de canola; 42,2 % e 22,2 %, no óleo de soja; 28,3 % e 29,2 %, no óleo de girassol;39,0 % e 17,9 %, no óleo de milho, respectivamente. As concentrações de alfa- e gama-tocoferol nos óleos vegetais reduziram significativamente após armazenamento, sob as condições empregadas no estudo.

The alpha- and gamma-tocopherol are among the homologues of vitamin E which plays a key role as anantioxidant. The richest dietary sources of vitamin E are vegetable oils. This study aimed at evaluating thealpha- and gamma-tocopherol contents in oils from canola, sunflower, corn and soybeans, and to verify their variations after storage time. The vegetable oils were purchased at supermarkets in Natal / RN, and they were keptat room temperature and protected from light. The tests was made at different times during storage (time 0 and after 30, 60 and 90 days). The high performance liquid chromatography (HPLC) was used to determinetheir concentrations. The statistical analysis was performed using analysis of variance (ANOVA) test and thedifferences were considered statistically significant when p < 0.05. By the end of the storage time (90 days), thealpha- and gamma-tocopherol contents showed a significant decrease of 38.7 % and 36.0 % for canola oil; 42.2 %and 22.2 % in soybean oil; 28.3 % and 29.2 % in sunflower oil; 39.0 % and 17.9 % in corn oil, respectively.The concentrations of alpha- and gamma-tocopherol in vegetable oils significantly decreased after the storageperiod under the conditions used in this study.

[Comparison between the serum concentration of alpha-tocopherol in puerperal women assisted in public and private maternities in Northeastern Brazil]. / Comparação entre a concentração sérica de alfa-tocoferol de puérperas assistidas em maternidades públicas e privadas no Nordeste do Brasil.

PURPOSE: To compare the concentration of serum alpha-tocopherol during the postpartum period in women admitted to public and private hospitals in Natal (RN), Brazil. METHODS: The study included 209 women in the postpartum period, 96 of them from private hospitals and 113 from public hospitals, studied between 24 and 48 hours postpartum. Inclusion criteria were: mothers aged 12 years or more, without diseases associated with pregnancy, who had given birth to a singleton with no malformations. Clinically decompensated women with multiple fetuses were excluded. A 5 mL blood sample was obtained from each participant under fasting conditions, before the first meal of the day. The concentration of alpha-tocopherol in serum (µg/dL) was determined by high performance liquid chromatography (HPLC). The statistical difference between means was tested by the Student's t-test. RESULTS: The mean concentration of alpha-tocopherol was 1.115.7 µg/dL in puerperae from the public network and 1.355.7 ± 397.6 µg/dL in puerperae from the private network , with a significant difference between groups (p=0.000687). Vitamin E concentration was determined individually and an alpha-tocopherol level <11.6 µmol/L or <499.6 µg/dL was considered to indicate deficiency. Vitamin E deficiency was detected in 5.3% of puerperae from the public network (n=6), whereas no deficiency was detected among women from the private network. However, low concentrations of alpha-tocopherol (11.6 to 16.2 µmol/L or 499.6 to 697.7 µg/dL) was detected in both groups, i.e., in 9.7% of the women from the public network (n=11) and in 4.2% for the women from the private network (n=4). CONCLUSION: These results highlight that women assisted in the public sector were more vulnerable to developing low concentrations of alpha-tocopherol than women assisted in the private sector.

Comparação entre a concentração sérica de alfa-tocoferol de puérperas assistidas em maternidades públicas e privadas no Nordeste do Brasil / Comparison between the serum concentration of alpha-tocopherol in puerperal women assisted in public and private maternities in Northeastern Brazil

OBJETIVO: Comparar a concentração de alfa-tocoferol no soro entre puérperas atendidas em maternidades das redes pública e privada da cidade de Natal (RN), Brasil. MÉTODOS: Participaram do estudo 209 puérperas, sendo 96 mulheres provenientes da rede privada e 113, da rede pública, entre 24 e 48 horas pós-parto. Foram incluídas no estudo parturientes com idade a partir de 12 anos, sem patologias associadas à gestação, que tiveram concepto único sem má-formação. Mulheres descompensadas clinicamente e com gestação múltipla foram excluídas. Amostras de 5 mL de sangue de cada participante foram coletadas no período de jejum, antes da primeira refeição do dia. A concentração de alfa-tocoferol no soro (µg/dL) foi determinada por cromatografia líquida de alta eficiência (CLAE). A diferença estatística entre as médias foi testada utilizando o teste t de Student. RESULTADOS: As médias da concentração de alfa-tocoferol nas puérperas da rede pública e da rede privada, respectivamente, foram 1.115,7±341,4 μg/dL e 1.355,7±397,6 μg/dL, tendo sido observada diferença estatisticamente significante (p=0,000687). Para avaliação individual da concentração de vitamina E, a deficiência foi identificada quando alfa-tocoferol <11,6 μmol/L ou <499,6 µg/dL. As puérperas da rede pública tiveram um percentual de 5,3% (n=6) de deficiência, enquanto nas participantes da rede privada tal carência não foi encontrada. Todavia, baixas concentrações (alfa-tocoferol entre 11,6-16,2 μmol/L ou 499,6-697,7 µg/dL) ocorreram tanto na rede pública como na privada: 9,7% (n=11) e 4,2% (n=4), respectivamente. CONCLUSÃO: Esses resultados destacam que as mulheres assistidas ...

PURPOSE: To compare the concentration of serum alpha-tocopherol during the postpartum period in women admitted to public and private hospitals in Natal (RN), Brazil. METHODS: The study included 209 women in the postpartum period, 96 of them from private hospitals and 113 from public hospitals, studied between 24 and 48 hours postpartum. Inclusion criteria were: mothers aged 12 years or more, without diseases associated with pregnancy, who had given birth to a singleton with no malformations. Clinically decompensated women with multiple fetuses were excluded. A 5 mL blood sample was obtained from each participant under fasting conditions, before the first meal of the day. The concentration of alpha-tocopherol in serum (µg/dL) was determined by high performance liquid chromatography (HPLC). The statistical difference between means was tested by the Student's t-test. RESULTS: The mean concentration of alpha-tocopherol was 1.115.7 µg/dL in puerperae from the public network and 1.355.7±397.6 µg/dL in puerperae from the privte network , with a significant difference between groups (p=0.000687). Vitamin E concentration was determined individually and an alpha-tocopherol level <11.6 µmol/L or <499.6 µg/dL was considered to indicate deficiency. Vitamin E deficiency was detected in 5.3% of puerperae from the public network (n=6), whereas no deficiency was detected among women from the private network. However, low concentrations of alpha-tocopherol (11.6 to 16.2 µmol/L or 499.6 to 697.7 µg/dL) was detected in both groups, i.e., in 9.7% of the women from the public network (n=11) and in 4.2% for the women from the private network (n=4). CONCLUSION: These results highlight that women assisted in the public sector were more vulnerable to developing low concentrations of alpha-tocopherol than women assisted in the private sector. .

Determinação de vitamina E na castanha de caju e sua relação com a recomendação nutricional em humanos / Determination of vitamin E in cashew and its relation to the nutritional recommendations in humans

O alfa-tocoferol é a forma biologicamente mais ativa da vitamina E. Sua principal função está associadaà capacidade antioxidante, que protege as membranas celulares dos danos ocasionados pelos radicaislivres. Pela importância da ingestão adequada desta vitamina e pela escassez de dados brasileirossobre seu teor nos alimentos, no presente estudo foi determinada a concentração de alfa-tocoferol emcastanhas de caju e o valor obtido foi comparado ao requerimento nutricional em vitamina E. Foramanalisadas quatro marcas de castanhas de caju torradas, obtidas em supermercados de Natal/RN. Oalfa-tocoferol das amostras foi obtido pela extração lipídica e sua determinação foi realizada por meiode CLAE. Os valores da concentração de alfa-tocoferol nas castanhas analisadas foram expressosem média e desvio padrão. A concentração média de alfa-tocoferol em 100 g de castanha de cajutorrada foi de 0,96 ± 0,12 mg. A quantidade desta vitamina contida na porção média de castanha decaju consumida pela população entrevistada foi correspondente a 3,6 % do requerimento nutricionaldiário em vitamina E. Conclui-se que as castanhas torradas analisadas não podem ser consideradascomo boas fontes de alfa-tocoferol, em virtude de não terem atingido a porcentagem de 10 a20 % do requerimento nutricional diário.