Analysis of cod-liver oil adulteration using Fourier Transform Infrared (FTIR) spectroscopy.

Analysis of the adulteration of cod-liver oil with much cheaper oil-like animal fats has become attractive in recent years. This study highlights an application of Fourier transform infrared (FTIR) spectroscopy as a nondestructive and fast technique for the determination of adulterants in cod-liver oil. Attenuated total reflectance measurements were made on pure cod-liver oil and cod-liver oil adulterated with different concentrations of lard (0.5–50% v/v in cod-liver oil). A chemometrics partial least squares (PLS) calibration model was developed for quantitative measurement of the adulterant. Discriminant analysis method was used to classify cod-liver oil samples from common animal fats (beef, chicken, mutton, and lard) based on their infrared spectra. Discriminant analysis carried out using seven principal components was able to classify the samples as pure or adulterated cod-liver oil based on their FTIR spectra at the selected fingerprint regions (1,500–1,030 cm−1)

Saccharin derivative synthesis via [1,3] thermal sigmatropic rearrangement: a multistep organic chemistry experiment for undergraduate students

Saccharin (1,2-benzisothiazole-3-one 1,1-dioxide) is an artificial sweetener used in the food industry. It is a cheap and easily available organic compound that may be used in organic chemistry laboratory classes for the synthesis of related heterocyclic compounds and as a derivatizing agent. In this work, saccharin is used as a starting material in a sequential synthesis designed for completion in three laboratory periods of 4 h each. This synthesis includes two nucleophilic substitutions, namely, the transformation of saccharin into saccharyl chloride and the addition of cinnamyl alcohol to saccharyl chloride (3-chloro-1,2-benzisothiazole 1,1-dioxide) to yield O-cinnamylsaccharin [(E)-3-(3-phenylprop-2-enoxy)-1,2-benzisothiazole 1,1-dioxide]. The third reaction is the isomerization of O-cinnamylsaccharin into N-cinnamylsacchain [2-(3-pheny1-2(E)-propen-1-yl)]-1,2-benzisothiazole-3(2H)-one 1,1-dioxide], a [1,3] sigmatropic rearrangement. The products are characterized using melting point, IR, and H-1 NMR spectroscopy. These experiments allow students to acquire experience in a multistep synthesis, practice the most typical laboratory scale synthesis, isolation, purification, and analytical methods, and think through and discuss the mechanisms of the intervening reactions

Synthesis-driven mapping of the dictyodendrin alkaloids

The dictyodendrin alkaloids have been described as the first telomerase inhibitors of marine origin. As such they represent interesting lead compounds in the quest for small molecule inhibitors of this tumor-marker enzyme. Described herein is the preparation of a collection of dictyodendrin-like compounds that hinges on the formation of their indole subunit by reductive cyclization of appropriate keto-amide precursors mediated by low valent titanium. It is shown that the underlying concept can be extended from the synthesis of heterocycles to the preparation of phenol and aniline derivatives using oxo-acid, oxo-nitrile or oxo-lactam derivatives as the substrates; such arene formations can even be carried out in cascade. Exploratory studies into the closure of the B-ring of the dictyodendrins with the aid of electrophilic reagents such as Ph3PAuCl/AgSbF6 or I+ revealed the bias of these polycyclic heteroarenes to undergo unusual skeletal rearrangements. It is demonstrated that the individual dictyodendrins and analogues are capable of cleaving double stranded DNA under oxidative conditions, provided that they exhibit at least one unprotected phenol group in their periphery

Report on the First Intercomparison

Ulberth, F. et al.The aim of the first intercomparison was twofold. Firstly, to select, stabilise and bottle suitable materials containing ca. 1 %, 5 % and 30 % total trans fatty acids (TFA) and demonstrate that packaging and storage does not affect oil composition, and secondly, to demonstrate that participating laboratories are able to achieve sufficient conformity of test results. Stabilising oil samples with tert. butylhydroquinone (250 mg/kg) and packaging in inert atmosphere in amber glass ampoules resulted in homogeneous and stable lots of preliminary test materials. Analytical precision of chromatographic methods to determine trans fatty acids (TFA) was acceptable (RSD(R) 1 g/100 g, but for levels 40 %). Misidentification of peaks and inconsistent peak integration practices are considered to be the major reasons for deviating results reported by the participants. Results obtained by chromatographic methods were in close agreement with those produced by spectroscopy (IR and NMR), thus proving that the applied chromatographic methods were not systematically biased. The intercomparison has to be repeated with new sets of samples. Special emphasis will be placed on the correct identification of trans polyenes in order to improve precision for low levels of TFA. To facilitate correct identification, the Co-ordinator will distribute equivalent chain length data for TFA.Contract no. SMT4-CT97-2144Peer Reviewe

Phytosterols in Plant Foods: Exploring Contents, Data Distribution and Aggregated Values Using an Online Bioactives Database

Information on the levels of plant-based bioactive compounds and their biological activity is broadly dispersed in the literature, and currently there is no central source of such data which can be used for scientific purposes such as biodiversity assessments, intake studies or for supporting health claims. A unique online database (EuroFIR-BASIS) has been developed to facilitate easy sourcing and analysis of extensive compositional and biological activity data for bioactive compounds. We extracted and interrogated the compositional information for one class of bioactives, the phytosterols (PS). Two types of data were extracted: (i) descriptive information for foods containing PS (e.g. levels and patterns of individual PS, distribution in food plants, variation within the plant/plant organs); and (ii) extended data sets which allowed statistical analysis of the data. The data closely followed a normal distribution for many plant/plant part/individual PS combinations, and facilitated the identification of outliers in the data sets which may have distorted any derived ‘typical’ values. Both of these approaches demonstrate the power of the EuroFIR BASIS database in bringing together compositional data for this class of bioactive compounds, which can equally be applied to any of the 16 compound classes currently covered in the database.JRC.D.6-Food Safety and Qualit

Phytosterols in Plant Foods: Exploring Contents, Data Distribution and Aggregated Values Using an Online Bioactives Database

Information on the levels of plant-based bioactive compounds and their biological activity is broadly dispersed in the literature, and currently there is no central source of such data which can be used for scientific purposes such as biodiversity assessments, intake studies or for supporting health claims. A unique online database (EuroFIR-BASIS) has been developed to facilitate easy sourcing and analysis of extensive compositional and biological activity data for bioactive compounds. We extracted and interrogated the compositional information for one class of bioactives, the phytosterols (PS). Two types of data were extracted: (i) descriptive information for foods containing PS (e.g. levels and patterns of individual PS, distribution in food plants, variation within the plant/plant organs); and (ii) extended data sets which allowed statistical analysis of the data. The data closely followed a normal distribution for many plant/plant part/individual PS combinations, and facilitated the identification of outliers in the data sets which may have distorted any derived ‘typical’ values. Both of these approaches demonstrate the power of the EuroFIR BASIS database in bringing together compositional data for this class of bioactive compounds, which can equally be applied to any of the 16 compound classes currently covered in the database.JRC.D.5-Food Safety and Qualit