Food preservatives sample preparation

Numerous CE separations have been published for synthetic colours, sweeteners and preservatives (Frazier et al., 2000a Sadecka and Polonsky, 2000 Frazier et al., 2000b). A rapid CZE separation with diode array detection for six common synthetic food dyes in beverages, jellies and symps was described by Perez-Urquiza and Beltran (2000). Kuo et al. (1998) separated eight colours within 10 minutes using a pH 9.5 borax-NaOH buffer containing 5 mM /3-cyclodextrin. This latter method was suitable for separation of synthetic food colours in ice-cream bars and fmit soda drinks with very limited sample preparation. However the procedure was not validated for quantitative analysis. A review of natural colours and pigments analysis was made by Watanabe and Terabe (2000). Da Costa et al. (2000) reviewed the analysis of anthocyanin colours by CE and HPLC but concluded that the latter technique is more robust and applicable to complex sample types. Caramel type IV in soft drinks was identified and quantified by CE (Royle et al., 1998). 

General Aspects Sample preparation for speciation analyses of solid foods is not as straightforward as previously shown for water and beverages. Extraction, clean-up, and preconcentration can be required and the preservation of the identity and original distribution of the species in the analyzed matrix is no simple matter. In order to obtain acceptable recoveries, extractions are usually repeated several times (each time the supernatant solution is separated from the... 

See also Air Analysis Sampling. Chromatography Overview Principles. Clinical Analysis Sample Handling. Drug Metabolism Metabolite Isolation and Identification. Extraction Solid-Phase Extraction. Food and Nutritional Analysis Sample Preparation. Forensic Sciences Volatile Substances. Headspace Analysis Purge and Trap. Perfumes. Sample Handling Sample Preservation Automated Sample Preparation. Sampling Theory. 

The general steps for sample preparation and sample processing are (1) sampling and size reduction, (2) comminution and homogenization, (3) pretreatments of the sample, such as predrying or defatting, (4) preservation of the prepared sample, and (5) cleanup of the analytical sample for instrumental analysis. This article covers the practical considerations of sample preparation necessary for food analysis. 

See also Carbohydrates Overview. Extraction Solid-Phase Extraction Supercritical Fluid Extraction. Food and Nutritional Analysis Sample Preparation Antioxidants and Preservatives Mycotoxins Oils and Fats. Lip-Ids Overview. Peptides. Proteins Overview. Toxins Mycotoxins Neurotoxins. Vitamins Overview Fat-Soluble Water-Soluble. 

The last decades have witnessed a growing interest in the search of new tools for food characterization. Any progress in analytical instrumentation is exploited to obtain more advanced description of foodstuff. Often the diffusion of a new methodology is hampered only by the complex sample preparation and the associated costs. Therefore methods that do not require any (or minimal) sample treatment are highly desired. Analysis of food products should require the use of non-invasive techniques because sensorial and safety properties are related to the structural and compositional complexity and heterogeneity of the matrix, which must be preserved as mueh as possible in its original state. 

Africa, where the sample in which the relevant strain had been discovered was taken. Pimaricin has been used as a vaginal suppository for the therapy of Candida infections and for other medical purposes like ophthalmic suspensions (Raab, 1972). Since the early 1960 s efforts have also been made to introduce it as a food preservative. Also in this case it has achieved a certain importance especially in the surface preservation of cheeses. Due to the currently increasing world-wide concern about the resistance of pathogenic bacteria against antibiotics it is discussed whether antibiotics used in food should be banned or its usage should be more restricted in the future. The addition of preparations containing pimaricin to cheese coatings based on polymer emulsions is still an important application in this industrial sector. 

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