Cristiane Bonaldi Cano

Determinação da diferença entre o valor real e o teórico do triglicerídeo ECN 42 para a detecção de adulteração em azeites de oliva comercializados no Brasil

CALCULATION OF THE DIFFERENCE BETWEEN THE ACTUAL AND THEORETICAL ECN 42 TRIACYLGLYCERIDE CONTENT TO DETECT ADULTERATION IN OLIVE OIL SAMPLES COMMERCIALIZED IN BRAZIL. The difference between the actual ECN 42 triacylglyceride content in vegetable oils, obtained by HPLC analysis, and the theoretical value calculated from the fatty acid composition was applied to detect the addition of seed oils with high contents of linoleic acid to olive oils commercialized in Brazil. The results indicate that samples analyzed were probably adulterated with low commercial value seed oils, rich in linoleic acid, like soybean, sunflower or corn.

Optimization of mobile phase for separation of carbohydrates in honey by high performance liquid chromatography using a mixture design

Um planejamento de misturas foi usado para otimizar a composicao da fase movel para a separacao dos carboidratos em mel por Cromatografia Liquida de Alta Eficiencia. Nove fases moveis ternarias de acetonitrila, agua e acetato de etila, correspondendo a um planejamento centroide simplex com pontos axiais foram testadas para separar os carboidratos mais frequentemente encontrados em amostras de mel. Os resultados sugerem que um modelo cubico especial descreve precisamente as mudancas nas proporcoes destes solventes na fase movel proxima a regiao otima da separacao dos picos. A adicao de um terceiro solvente, acetato de etila, a fase movel binaria de agua e acetonitrila permitiu uma melhora significativa na separacao dos carboidratos que pode ser aplicada a analise quantitativa destes compostos em mel.

Precisão dos métodos refratométricos para análise de umidade em mel

For the determination of the moisture contents of honey, the Brazilian legislation adopts the refractometric method proposed by AOAC. However, in other work, the authors observed that the crystallization interferes in the refractive index measurement when the honey sample if encountered crystallized and, therefore, moisture contents overestimated were obtained. The European Honey Commission (EHC), adopt other refractometric method that use a pre-treatment of sample when this one was crystallized. So, the objective of this work was to compare the precision of these refractometric methods by different statistical techniques and it establish thus the more adequate procedure for moisture analysis in honey. The results of t-tests analysis in the 95% confidence level for the average moisture contents of the honey samples suggested that there were significant differences between the two-refractometric methods (AOAC e EHC) only for the crystallized samples. The analysis of standard deviations by application of F-test and building of confidence intervals shown that the EHC method was more precise than the AOAC methodology for the crystallized honey samples. In this way, it may be suggested the adoption by Brazilian legislation of refractometric method of EHC, as official method, by this one not present systematic errors.