Food matrix, effect

Keck, A.S., Qiao, Q., and Jeffery, E.H., Food matrix effects on the bioactivity of broccoli-derived sulforaphane in liver and colon of F344 rats, J. Agric. Food Chem., 51, 3320-3327, 2003. 

Organotypic models, available for all organs involved in ADME, are used to study food matrix effects, intestinal metabolism/stability, and regional differences in permeability. The latter is of particular importance since it has been shown that permeability to various marker molecules varies along the intestinal tract in general, permeability decreases in the order jejunum > ileum > colon [54]. The half-lives of organotypic models limits the duration of possible studies to 1-3 hours. 

When discussing the biological activity of flavonoids in general, and flavanols in particular, there are some major factors to be considered bioavailabDity from food, matrix effects, absorption and metabolism in the gastrointestinal tract, tissue and cellular distribution after absorption, possible interactions and/or accumulation, which are the chemical form(s) biologically available to the cell/tissue and their potential metabolism at cellular level [3, 42, 69, 70]. 

The concentration of Cu is usually low in food samples, therefore developing sensitive and selective methods for Cu quantification are required. Among the electrochemical techniques, stripping analysis following adsorption accumulation of Cu chelates has demonstrated high sensitivity however after some time of accumulation, metal and chelates may strongly adsorb on the electrode surface. Most of the authors used the standard addition method not only to minimize the food matrix effects, but also to improve the resolution of the voltammetric technique. An ASV procedure at a platinum rotatory disk electrode without the need of Cu-complex formation has been proposed to determine the Cu content of tequila samples [26]. 

The most sensitive assay for ricin was based on immunoPCR (He et al., 2010b). The method used the ricin sample bound to a 96-well plate, which then bound streptavidin-labeled antibody to ricin. A biotinylated strand of DNA 340-bp long was then captured by the streptavidin, the DNA enzymatically released, and then amplified and quantified by real-time PCR (RT-PCR) in a separate plate. This assay is 10-fold to 1000-fold more sensitive than ELISA assays in detecting ricin in food samples, depending on food matrix effects that influence the sensitivity of the assay. As a result of its sensitivity, it was possible for the first time to monitor levels of ricin in the bloodstream of mice treated with ricin (He et al, 2010b). 

Because of the possibility that the herbicide alachlor could adulterate food if either poultry or livestock consumed contaminated materials, Lehotay and Miller evaluated three commercial immunoassays in milk and urine samples from a cow dosed with alachlor. They found that milk samples needed to be diluted with appropriate solvents (1 2, v/v) to eliminate the matrix effect. One assay kit (selected based on cost) was also evaluated for use with eggs and liver samples from chickens. Egg and liver samples were blended with acetonitrile, filtered, and diluted with water. Linear calibration curves prepared from fortified egg and liver samples were identical... 

Although SPME was applied initially for the analysis of relatively volatile environmental pollutants in waters, rapid developments have enabled SPME to be successfully applied for the analysis of pesticides in water, wine and more complex food samples such as honey, fruit juice and pears, vegetables and strawberries. With food samples, most analysts recognize the need for some sample pretreatment in order to minimize matrix effects. The matrix can affect the SPME efficiency, resulting in a reduced recovery of pesticides. The most common method is simply to dilute the sample or sample extract with water. Simpltcio and Boas comminuted pears in water prior to the determination of pesticides. Volante et al. extracted over 100 pesticides... 

The development of new fiber coatings in the near future should further improve the specificity of SPME and overcome some of the observed matrix effects. Quantification by stable isotope dilution gas chromatography/mass spectrometry (GC/MS) may assist in improving analytical performance. Along with the possible application of micro LC and capillary LC columns to in-tube SPME, the development of novel derivatization methods and the potential for the analysis of fumigant pesticides, SPME appears to be a technique with a future in the analysis of pesticide residues in food. 

Limiting Factors for Absorption Effects of Food Matrix... 

Due to the complexity of the food samples, it is possible that the presence of some compounds in the matrix interferes with analyte determination even when working in LC-MS/MS, certain compounds present in the sample can affect the initial ionization of the analyte through what is often called ion suppression/ enhancement or matrix effects. 

The development of multiclass methods for the detection of antibacterials and coccidiostats in food samples has shown a growing interest during the last years since the regulations concerning the presence of such chemicals in animal-derived foodstuffs is becoming more and more stringent. The challenges that these types of analyses pose to the analysts mainly have to do with the complexity of the matrix and the different physicochemical properties of the antibacterial families. Therefore, very often, a purification and preconcentration step is required prior to analysis in order to minimize matrix effects and reach the desired sensitivities [192, 193]. 

APCI is widely used nowadays in different application fields for low molecular weight analytes. Many of them can either be analyzed with ESI or APCI, and the choice of the method should take into account several aspects, such as the physical-chemical properties of the molecule, the mobile phase composition and the required flow rate, and possible matrix effects. Typical APCI applications are in pharmaceutical, environmental, and food safety analysis. 

Similarly, using our standard method for column chromatography, quantitative separation was obtained, for Erythrosine, but also for the other food dyes in contemporary use It is also notable that there was no significant matrix effect observed for DI, tap or well water. 

Fig. 3.1 Three factors influence flavour perception. The first includes all aspects that are related solely to the food, such as the aroma-active compounds present and interactions between the food matrix and aroma compounds. The second comprises all aspects related to the in-mouth situation. This makes the person eating the food an integral part of the system being analysed, and takes account of interactions between food and consumer. Finally, psychosocial and cognitive effects modulate aroma perception...

The bioavailibility of quercetin-glycosides from onions, containing mainly quercetin-p-glucosides, was superior to that of various quercetin glycosides from apples (containing a mixture of quercetin-(3-galactosides and P-xylosides) and of pure quercetin-3-mtinoside (major species in tea). The possible matrix effect of the foods remains unclear. 

Bakker, J., Brown, W., Hills, B., Boudaud, N., Wilson, C., and Harrison, M. 1996. Effect of the food matrix on flavour release and perception. In Flavour Science Recent Developments (A.J. Taylor and D.S. Mottram, eds.) pp. 369-374. The Royal Society of Chemistry, Cambridge, U.K. 

Provides information on the effects of volatile compound character, food matrix, and temporal release profiles. 

It is essential for a successful assay that the vitamins be quantitatively extracted from the food matrix in a form that can be accurately measured by the particular HPLC technique to be used. An effective extraction procedure serves to homogenize and concentrate the sample, isolate the vitamin analyte from its association with protein, eliminate as far as possible known interfering substances, and destroy any indigenous enzyme activity. The vitamin-rich fraction thus obtained may require some form of cleanup before the vitamins can be measured, particularly when measuring the trace amounts of naturally occurring vitamins D and K. 

The fat-soluble vitamins can be extracted from the food matrix without chemical change using a solvent system that is capable of effectively penetrating the tissues and breaking lipoprotein bonds. A total lipid extraction is required for the simultaneous determination of vitamers or vitamins with a wide range of polarities, and, for this purpose, a mixture of chloroform and methanol (2 + 1) is highly efficient (82). The Rose-Gottlieb method is particularly suitable for ex-... 

---