Quantification of folate in fruits and vegetables: A fluorescence-based homogeneous assay

Secondary metabolite components of kiwifruit

Both green and gold kiwifruit contain high concentrations of vitamin C, and much of the "health story" of kiwifruit involves this vitamin. Kiwifruit also contain other compounds that are bioactive and beneficial to health. In this chapter, the secondary metabolite composition of kiwifruit is presented. Although there are limited compositional data for kiwifruit published in the scientific literature, the concentrations of 42 compounds have been documented. Included are compounds that are often associated with "healthfulness," such as the vitamins (A, C, E, and K), carotenoids (lutein and β-carotene), folate, and antioxidant phenolic compounds. Metabolite discovery is advancing rapidly with the introduction of "metabolomic" studies where the goal is to identify and measure the complete metabolite composition of a sample. In a metabolomic experiment using liquid chromatography and high-resolution mass spectrometry, it was possible to measure more than 500 metabolites in kiwifruit extracts. The large number of detectable metabolites present suggests that there is an abundance of kiwifruit metabolites still to be discovered. Such studies will provide a more complete understanding of the metabolite composition of kiwifruit that will lead to new and improved hypotheses as to the function and effects of kiwifruit metabolites, including their relevance to human health.

Investigation of protocols to extraction and quantification of folates in vegetables matrices split into liquor and fiber fraction using factorial design

The main protocols of extraction were investigated for the six folate forms in vegetable matrices, treated in two fractions, liquor and fiber. In a pilot study, it was used ammonium acetate added of 2-mercaptoetanol and ascorbic acid as extraction solution. The condition of use of protease and folate conjugase was evaluated, besides alternative treatments without enzyme use. Based on the results of this stage, it was built the factorial design 2(4), with three replications at the central point, using the following variables: temperature, time for reaction, molar concentration of the extraction solution and ratio sample/solution as independent variables and dependent variable, the amount of each folate form extracted as well as spectral and chromatographic parameters. In the pilot study it was verified that the enzyme use can cause an increase in the variability of the folate content, which enabled to build the factorial design without the enzyme use. The binomial time and temperature showed greatest impact on the extraction profile, besides high concentrations of ammonium acetate resulting in bifurcation of some peaks. 5-Methyltetrahydrofolate was extracted primordially in the liquor fraction, indicating that this treatment on the matrix provoked suitable extraction condition to this folate.