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Journal ArticleDOI

New simple spectrophotometric assay of total carotenes in margarines

28 Jul 2006-Analytica Chimica Acta (Elsevier)-Vol. 573, pp 466-473

TL;DR: For the first time saponification step used in determination of carotenes in margarines was omitted leading to a substantial cost saving and reduction of time needed to complete the analysis.

AbstractDirect and reliable spectrophotometric method for assaying total carotenes (TC) in margarines with the minimum of sample manipulation is proposed. For the first time saponification step used in determination of carotenes in margarines was omitted leading to a substantial cost saving and reduction of time needed to complete the analysis. The resulting analytical procedure is characterized in details in terms of the figures of merit. The method is sensitive, precise and accurate; for both, standard additions and calibration in soybean oil, recovery ranges between 98 and 102%. For the most accurate analyses the approach of standard additions is preferred but for quick routine analyses this latter can be replaced by the calibration in soybean oil. Limit of detection value (LOD = 3S.D.B/a, where S.D.B is the standard deviation of the blank, “a” is the slope of calibration line) as low as 12 μg TC/100 g was achieved in soybean oil enabling the sensitive detection. Concentration of TC in margarines declared as being coloured with β-carotene (carotene) ranges between 0.3 and 0.9 mg/100 g while in carrot extract-coloured margarine TC is 0.2 mg/100 g.

Topics: Standard addition (52%), Detection limit (50%)

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Citations
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Journal ArticleDOI
Abstract: Cold-pressed linseed and camelina oils have been available on the global market for many years. They are known for their high contents of polyunsaturated fatty acids (PUFAs), mainly α-linolenic (ALA). This study aimed to evaluate the quality and oxidative stability of linseed and camelina cold-pressed oils purchased in retail outlets in Poland. The fatty acid composition, peroxide value, acid value, anisidine value, chlorophyll pigments, carotenoid pigments, and oxidative stability of these oils were analyzed. It was found that all analyzed oils meet the standards of requirements of the Codex Alimentarius (2009) for cold-pressed oils. The content of chlorophyll and carotenoid pigments of linseed and camelina oils was significantly different. The percentage composition of PUFAs was high in both types of oils, but it was significantly higher in linseed than in camelina oils. The results of Rancimat and PDSC tests show low oxidative stability of all tested oils, although camelina oils were more stable than linseed oils. 1 Practical applications Based on the study, it can be concluded that linseed and camelina oils should be included in the human diet to provide an optimal ratio of omega-6 to omega-3 fatty acids. The differences between tested oils of the same seed species were significant. This study shows that quick methods of testing an oils oxidative stability (Rancimat and PDSC) may be successfully applied in oil studies. The study evaluates the quality of cold-pressed linseed and camelina oils purchased in retail outlets in Poland. The research shows a correlation (r = −0.673) between content of polyunsaturated fatty acids and oxidative stability of tested oils. Oxidative stability was determined by Rancimat test and fatty acid composition by GC-FID.

25 citations


Journal ArticleDOI
TL;DR: The authors' data points to the inertness of t-test to detect significance of differences, particularly at low R values, and the higher correlation coefficient, the higher is sensitivity of statistical testing, especially of the paired t- test.
Abstract: This report is aimed at intra-laboratory and inter-laboratory comparison of the results obtained during spectrophotometric and HPLC analyses of lycopene, β-carotene and total carotenoids in tomato products and yellow maize flours/grits. Extensive statistical analyses are performed in order to identify the main sources of uncertainties which may occur when using: (i) different techniques/methods/approaches in the same/different laboratories, in various food samples, and (ii) to indicate the facts/conditions under which the biases between results may remain unidentified after applying statistical testing. Our data points to the inertness of t-test to detect significance of differences, particularly at low R values: in general, the higher correlation coefficient, the higher is sensitivity of statistical testing, especially of the paired t-test. Therefore, simple deviation of relationship line slope from unity could be used as additional evaluation parameter. This adds to reliable and objective quality assurance of foods in regard to carotenoids.

20 citations


Journal ArticleDOI
TL;DR: An optimized detection geometry for absorption measurements in opaque liquids is described, using two orthogonal detectors based on piezoelectric poly(vinylidene fluoride) (PVDF) forulsed laser photoacoustic spectroscopy.
Abstract: In many relevant industrial applications, UV−vis online process monitoring is hampered by light scattering and opacity of the samples, whereas diluted and filtered samples are rarely available. Pulsed laser photoacoustic (PA) spectroscopy allows the measurement of both high and low absorptions without any need for sample preparation. An optimized detection geometry for absorption measurements in opaque liquids is described. The proposed PA sensor was realized by using two orthogonal detectors based on piezoelectric poly(vinylidene fluoride) (PVDF). Laser-induced pressure waves were sensed perpendicularly to (side-on mode) and along the axis of the laser beam (forward mode). Pressure waves generated by a single laser pulse, optical transmission and absorption, as well as the speed of sound in liquid samples were determined simultaneously using time-resolved detection. Evaluation of the PA signal permits the determination of absorption coefficients ranging from 0.1 to 1000 cm−1. The influence of absorbing o...

20 citations


Journal ArticleDOI
Abstract: Photoacoustic spectroscopy (PAS) and optothermal window (OW) with a cw Ar ion laser used as a radiation source at 476.5, 488 and 496 nm were applied to quantify total carotenes (TC) in margarines. Both techniques, being rapid and extremely simple, allow for direct measurement without any pretreatment of the sample. The PAS has proven precise and sensitive enough to allow quantitation of TC in margarines containing 1–9 mg TC/kg, in applications such as the quality control of intermediate and final products. The sensitivity of OW is lower than that of PAS but the approach can still be used for quantitation of TC in margarine matrices at much higher concentrations.

15 citations


Book ChapterDOI
01 Jan 2012
TL;DR: This chapter discusses the various types of food adulteration and similar fraudulent practices, with details of methods of detection.
Abstract: The relative potential of various technologies for the confirmation of food authenticity and quality will be discussed. The potential and ease of application of the techniques in industrial and laboratory settings that have found new applications in the field of quality assurance will be covered. The use of specific techniques coupled with chemometric tools for the classification of unknown food samples and/or the prediction of some physicochemical properties will also be included in this chapter. The techniques that will be discussed are spectroscopy [Ultraviolet–visible (UV-Vis), near infrared (NIR), middle infrared (MIR), and Raman)], isotopic analysis, chromatography, mass spectrometry (MS), and its combinations with chromatography, electronic nose, polymerase chain reaction (PCR), enzyme-linked immunosorbent assay, and thermal analysis. Some examples will illustrate that there has always been a risk of fraud, since food became a trade object. This chapter will discuss the various types of food adulteration and similar fraudulent practices, with details of methods of detection. Most of the research studies from 2011 till date will be included in this chapter. For the studies conducted before 2011, we recommend the reader to refer to the first edition of this book.

12 citations


References
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Journal ArticleDOI
19 Mar 1981-Nature
TL;DR: If dietary β-carotene is truly protective—which could be tested by controlled trials—there are a number of theoretical mechanisms whereby it might act, some of which do not directly involve its ‘provitamin A’ activity.
Abstract: Human cancer risks are inversely correlated with (a) blood retinol and (b) dietary beta-carotene. Although retinol in the blood might well be truly protective, this would be of little immediate value without discovery of the important external determinants of blood retinol which (in developed countries) do not include dietary retinol or beta-carotene. If dietary beta-carotene is truly protective--which could be tested by controlled trials--there are a number of theoretical mechanisms whereby it might act, some of which do not directly involve its 'provitamin A' activity.

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Journal ArticleDOI
TL;DR: Thirty-four carotenoids, including 13 geometrical isomers and eight metabolites, in breast milk and serum of three lactating mothers have been separated, identified, quantified, and compared by high-performance liquid chromatography (HPLC)-photodiode array (PDA) detection-mass spectrometry (MS).
Abstract: Thirty-four carotenoids, including 13 geometrical isomers and eight metabolites, in breast milk and serum of three lactating mothers have been separated, identified, quantified, and compared by high-performance liquid chromatography (HPLC)−photodiode array (PDA) detection−mass spectrometry (MS). Among the metabolites were two oxidation products of lycopene and four of lutein/zeaxanthin. In addition, two metabolites of lutein, formed as a result of dehydration of this dihydroxycarotenoid under acidic conditions similar to those of the stomach, have also been identified in plasma and breast milk. The oxidative metabolites of lycopene with a novel five-membered-ring end group have been identified as epimeric 2,6-cyclolycopene-1,5-diols by comparison of their HPLC−UV/visible−MS profiles with those of fully characterized (1H- and 13C-NMR spectroscopy) synthetic compounds. The HPLC procedures employed also detected vitamin A, two forms of vitamin E (γ- and α-tocopherol), and two non-carotenoid food components, ...

520 citations


Journal ArticleDOI
Abstract: Identification, structure moleculaire et dosage, avant et apres cuisson, des principaux constituants des pigments de broccoli, choux, epinards, choux de Bruxelles, choux frises et quelques especes de Brassica

372 citations


Book
01 Jan 1981
TL;DR: Carotenoids as Food Color, H. Klaui and J.C. Bauernfeind, and Carotenoid Analytical Methods, E.E. Purcell.
Abstract: List of Contributors Foreword Preface Natural Food Colors, JC Bauernfeind Carotenoids as Food Color, H Klaui and JC Bauernfeind Oxycarotenoids in Poultry Feed, WL Marusich and JC Bauernfeind Carotenoids in Fish Feeds, KL Simpson, T Katayama, and CO Chichester Carotenoids in Wild and Captive Birds, AH Brush Carotenes and Other Vitamin A Precursors in Animal Feed, JC Bauernfeind, CR Adams, and WL Marusich Carotenoids in Pharmaceutical and Cosmetic Products, K Munzel Carotenoids in Medical Applications, MM Mathews-Roth Carotenoids as Photoconductors, JO Williams Carotenoid Analytical Methods, E De Ritter and AE Purcell Index

154 citations


Journal ArticleDOI
Abstract: A sensitive HPLC multimethod was developed for the determination of the carotenoid food additives (CFA) norbixin, bixin, capsanthin, lutein, canthaxanthin, β-apo-8′-carotenal, β-apo-8′-carotenoic acid ethyl ester, β-carotene, and lycopene in processed food using an RP C30 column. For unequivocal identification, the mass spectra of all analytes were recorded using LC–(APcI)MS. For extraction, a manual process as well as accelerated solvent extraction (ASE) was applied. Important ASE parameters were optimized. ASE was used for the first time to extract CFA from various food matrices. Average recoveries for all analytes ranged from 88.7–103.3% (manual extraction) and 91.0–99.6% (ASE), with exception of norbixin using ASE (67.4%). Limits of quantitation (LOQ) ranged from 0.53–0.79 mg/L. The presented ASE method can be used to monitor both, forbidden application of CFA or the compliance of food with legal limits.

113 citations