A. Rodríguez-Bernaldo de Quirós

Protein, amino acid and fatty acid contents in raw and canned sea urchin (Paracentrotus lividus) harvested in Galicia (NW Spain)

Moisture, protein, amino acid and fatty acid contents of raw and canned sea urchin (Paracentrotus lividus) gonads were determined. Sea urchin showed a high moisture content (73%) and a high level of proteins (56% dry matter). The canning process, evaluated at 112 °C for 50 min, did not lead to significant changes in protein, amino acid and fatty acid contents relative to the raw sample. © 2000 Society of Chemical Industry

Rapid multi-analyte quantification of benzophenone, 4-methylbenzophenone and related derivatives from paperboard food packaging

Photo-initiators are used in printing inks hardened with UV light and one of the most commonly used photo-initiators is benzophenone (BP). Recent notifications under the Rapid Alert System for Food and Feed have shown migration of 4-methylbenzophenone (4-MBP) from packaging into cereals. A specific migration limit exists for BP of 0.6 mg kg−1 for its use as an additive in plastics. There is no specific European legislation covering cardboard boxes and/or printing inks for food contact use. However, due to the high levels detected, the European Food Safety Authority (EFSA) published recommendations and the Standing Committee for the Food Chain and Animal Health endorsed a limit of 0.6 mg kg−1 for the sum of BP and 4-MBP. While studies have been published on photo-initiators in the past, there is a fundamental lack of data on 4-MBP especially for its combined analysis with others. We present an HPLC method with diode array detector to simultaneously determine the levels of BP, 4-MBP as well as 7 other possible derivatives from secondary packaging for food applications. The method was tested and applied to 46 samples of paperboard for secondary packaging collected both from supermarkets and directly from a paperboard supplier. In addition, a survey was conducted on recycled paperboard (n = 19) collected from a supplier, to evaluate the background quantity of BP and other derivatives in recycled board. The most abundant photo-initiator found in the survey was BP, in 61% of samples, and 4-MBP was found in 30% of the samples. It seems that these compounds are used to replace one another. Other derivatives were found in minor quantities. Traces of BP were also found in 42% of the samples of recycled, unprinted board.

Separation of phospholipid classes in sea urchin, paracentrotus lividus by high-performance liquid chromatography.

A simple high-performance liquid chromatography (HPLC) method for determination of major phospholipid classes in sea urchin Paracentrotus lividus is described. The separation was performed on a Tracer Extrasil SI 5 microm 25 x 0.4 cm column and an isocratic mobile phase of acetonitrile-methanol 85%-phosphoric acid (50:50:1.8, v/v). The HPLC method utilizes UV detection at 205 nm. Five phospholipids were identified and quantified: phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylcholine (PC) and sphingomyelin (SM). Fresh and canned samples were analyzed. Students t-test showed no significant difference (P < or = 0.05) between the mean phospholipid contents of raw and canned sea urchin.

HPLC analysis of organic acids using a novel stationary phase.

In the present work, a high performance liquid chromatographic method with UV detection for the separation of six organic acids including, tartaric, malic, acetic, lactic, citric and succinic is described. The separation was performed on a novel stationary phase TEKNOKROMA, Tr-010065 Mediterranea sea(18) (15 cm x 0.4 cm, i.d. 3 microm) and using water with a 0.1% (v/v) of formic acid as mobile phase. The advantages of this packing over a conventional octadecylsilane (ODS2) column are reported. The method was validated with respect to linearity, limits of detection and repeatabilities within day and between days and satisfactory results were obtained. The proposed method was applied for the determination of these compounds in commercially available white wines. The samples were injected directly without previous treatment. LC-MS was used as a confirmatory technique.

Determination of vitamin C in sea urchin: Comparison of two HPLC methods

SummaryA UV-detection and a fluorimetric-detection HPLC method were compared for the determination of ascorbic acid levels in sea urchin gonad. The UV detection method (direct determination of ascorbic acid at 245 nm) gave a detection limit of 0.19 μg mL−1 and reproducibility (6 assays of a sea urchin gonad sample) of 6.35%. The fluorimetric detection method (oxidation of ascorbic acid to dehydroascorbic acid, treatment with 1,2-phenylenediamine to convert the dehydroascorbic acid to a fluorescent product, and fluorimetric detection of the product) gave a detection limit of 0.082 μg mL−1 and reproducibility of 0.61%. The fluorimetric method is thus preferable for determination of vitamin C in sea urchin gonad.

Analytical method for the simultaneous determination of polyfunctional amines used as monomers in the manufacture of food packaging materials.

This paper describes the development of a multi-analyte method for the determination of polyfunctional amines commonly used as monomers in the manufacture of food contact materials. Amines were analyzed by high-performance-liquid chromatography with diode-array detection (HPLC-DAD) after derivatization with dansyl chloride. The chromatographic analysis and the derivatization conditions were optimized. The proposed method was validated in terms of linearity, limits of detection and repeatabilities. The method showed an excellent sensitivity (LOD≤0.05 μg/mL) and appropriate repeatabilites (RSD (n=7)≤5%)). LC-MS/MS was used as a confirmatory technique. The stability of the amines in five food simulants (distilled water, 3% acetic acid, 10% ethanol, 50% ethanol and olive oil) under the most common testing conditions (10 days at 40 °C) was also studied. Results showed that amines had an acceptable stability in aqueous simulants but in the olive oil a loss of 100% was observed for all analytes.

Liquid Chromatographic Determination of Malvidin-3-O-Glucoside and Malvidin 3, 5-O-Diglucoside in Wine Samples by Direct Injection~!2008-04-11~!2008-05-06~!2008-06-12~!

A method for the determination of malvidin 3-O-glucoside (Oenin), and malvidin 3, 5-O-diglucoside (Malvin) in wines by on line HPLC coupled with UV, and fluorescence detectors is described. With the proposed method the samples were analysed by direct injection without a previous treatment. For method validation, satisfactory recoveries (> 95%) and suitable repeatabilities (within day: R.S.D. (n=6=) < 3%, and between days; R.S.D. (n=6=) < 3%) were achieved. The method was applied to the analysis of commercially available red wines.

Chapter 29 – Antimicrobial Food Packaging Based on Biodegradable Materials

This chapter provides an overview of studies about antimicrobial (AM) food packaging based on biodegradable materials. Due to the environmental problems related to non-biodegradability of petrochemical-based plastics, biopolymers are now being considered as an alternative to synthetic polymers for several applications, including AM packaging for food. Food products naturally contain some microorganisms that, depending on the preservation method, can proliferate and adulterate the product. To control and minimize the microbiological hazards of foodborne pathogens, as well as to predict and enhance the shelf life of food products, AM biodegradable films have been developed. A wide range of natural and chemical AM agents can be incorporated into packaging system to control or suppress the activities of targeted microorganisms. AM biodegradable films are promising food packaging materials because of their biodegradability; however, more research is needed to develop AM packaging systems for more effective bacterial inhibition.

Comparison of two stationary phases for the separation of five selected polyphenols.

In this study, a conventional TEKNOKROMA, Tr-015605 TRACER EXTRASIL ODS2 (25 cm x 0.4 cm, i.d. 5 microm) column and a new stationary phase TEKNOKROMA, Tr-010065 Mediterranea sea(18) (15 cm x 0.4 cm, i.d. 3 microm) were compared for the separation of five phenolic compounds. Sensitivity, performance characteristics, analysis time and method validation were reported for both columns. A better sensitivity and performance were achieved with the novel chromatographic support. In addition the total analysis time was significantly reduced. The method was applied to the determination of the selected polyphenols in commercial available white wines. LC-MS was used as a confirmatory technique.

Instability of an aromatic amine in fatty food and fatty food simulant: characterisation of reaction products and prediction of their toxicity

It is a well-known fact that amines are not stable in food of a fatty nature. In this study the synthesis and characterisation of the products obtained as a result of the reaction of amines in a fatty medium are reported. Based on the well-known reactions among amines and acid and esters groups, two novel compounds were synthesised using m-xylylenediamine (mXDA), a primary diamine widely used as monomer in the manufacture of food contact materials and two fatty acids, oleic acid and palmitic acid, which occur in most fats. The resulting compounds were two molecules belonging to the family of fatty acid amides, dioleamide and dipalmitamide. A complete characterisation of both products was carried out employing several techniques such as infrared spectroscopy, 1H- and 13C-NMR spectroscopy, electron ionisation mass spectrometry, LC-MS/MS and UV spectrometry. The results obtained by the different techniques were well correlated. In the second part of the work, the formation of these compounds in real samples was evaluated. For this purpose a certain volume of olive oil was spiked with a known amount of mXDA. Olive oil was selected as a fatty medium since it is a widely consumed food and additionally is used as a fatty food simulant in migration studies of food contact materials. A method was developed to extract the fatty acid amides from the fatty matrix, which were then identified by LC-MS/MS. The toxicity of the synthesised compounds was predicted using a toxicity estimation software tool. Graphical Abstract