Simultaneous determination of acrylamide, asparagine and glucose in food using short chain methyl imidazolium ionic liquid based ultrasonic assisted extraction coupled with analyte focusing by ionic liquid micelle collapse capillary electrophoresis

Review of Research into the Determination of Acrylamide in Foods

Acrylamide (AA) is produced by high-temperature processing of high carbohydrate foods, such as frying and baking, and has been proved to be carcinogenic. Because of its potential carcinogenicity, it is very important to detect the content of AA in foods. In this paper, the conventional instrumental analysis methods of AA in food and the new rapid immunoassay and sensor detection are reviewed, and the advantages and disadvantages of various analysis technologies are compared, in order to provide new ideas for the development of more efficient and practical analysis methods and detection equipment.

Thiol-ene Click Derivatization for the Determination of Acrylamide in Potato Products by Capillary Electrophoresis with Capacitively Coupled Contactless Conductivity Detection

The development of analytical methods for acrylamide formed during food processing is of great significance for food safety, but limited by its inherent characteristics, the analysis of acrylamide is a continuing challenge. In this study, an efficient derivatization strategy for acrylamide based on thiol-ene click reaction with cysteine as derivatization reagent was proposed, and the resulting derivative was then analyzed by capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C⁴D). After systematic investigation including catalyst dosage (0-20 mM), reaction temperature (30-90 °C) and time (1-60 min), and cysteine concentration (0.2-3.6 mM), acrylamide could be efficiently labeled by 2.0 mM cysteine at 70 °C for 10 min using 4 mM n-butylamine as catalyst. Application of 10 mM triethylamine as separation buffer, the labeled acrylamide was analyzed within 2.0 min, and the relative standard deviations of migration time and peak area were less than 0.84% and 5.6%, indicating good precision. The C⁴D signal of acrylamide derivative showed a good linear relationship with acrylamide concentration in the range of 7-200 μM with the correlation coefficient of 0.9991. The limit of detection and limit of quantification were calculated to be 0.16 μM and 0.52 μM, respectively. Assisted further by the QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample pretreatment, the developed derivatization strategy and subsequent CE-C⁴D method were successfully applied for the determination of acrylamide in potato products.

Controlled release of methylene blue from glutaraldehyde-modified gelatin

Gelatin has been identified as a valuable material for controlled release of food ingredients because of its highly ramified three-dimensional network. In the present work, gelatin was further modified with glutaraldehyde (GA) and prepared as microspheres to further improve its control to release of food ingredients. Features (i.e., chemical structures, thermal properties, network structures, and methylene blue (MB) release kinetics) of both the unmodified and GA-modified gelatin microspheres were investigated. Results showed that the application of GA enhanced the formation of intramolecular and/or intermolecular crosslinking of gelatin and improved its thermal stability. Besides, the release efficiency of MB from the GA-modified gelatin was less affected by temperature and pH value compared to the unmodified gelatin. Kinetics analysis proved that the release of MB from gelatin followed the first-order kinetics. Both the release constant (k) of MB and the diffusion coefficient (D_a ) of GA-modified gelatin were significantly lower than those of the unmodified gelatin. PRACTICAL APPLICATIONS: Gelatin is a valuable material for the release control of food ingredients (e.g., oils, vitamins, antioxidants, and flavor compounds) attributes to its highly ramified three-dimensional network. However, the low mechanical strength of gelatin makes it susceptible to many environmental factors and has restricted its application. In the present work, gelatin was modified by glutaraldehyde (GA). The chemical structure, thermal properties, network structure, and methylene blue release kinetics of the GA-modified gelatin microspheres were properly investigated. This research proved that GA-modified gelatin could be a potential carrier for the release control of given food contents in food industry.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

This review work presents and discusses the main applications of capillary electromigration methods in food analysis and Foodomics. Papers that were published during the period February 2015-February 2017 are included following the previous review by Acunha et al. (Electrophoresis 2016, 37, 111-141). The paper shows the large variety of food related molecules that have been analyzed by CE including amino acids, biogenic amines, carbohydrates, chiral compounds, contaminants, DNAs, food additives, heterocyclic amines, lipids, peptides, pesticides, phenols, pigments, polyphenols, proteins, residues, toxins, vitamins, small organic and inorganic compounds, as well as other minor compounds. This work describes the last results on food quality and safety, nutritional value, storage, bioactivity, as well as uses of CE for monitoring food interactions and food processing including recent microchips developments and new applications of CE in Foodomics.

Color and alcohol removal for the simultaneous detection of amino acids and sugars in wine by two-dimensional ion chromatography

An effective pretreatment method for wine color removal by a PS-DVB SPE cartridge and online alcohol elimination by valve switching was presented. The optimum parameters for color removal were investigated: 40-μm and 100Å poly (styrene)-divinylbenzene (PS-DVB) (0.4g) was selected as the color removal material and 5mL of ethanol (10%) as the elution solvent for sample pretreatment under given condition. Moreover, an accurate and automated two-dimensional ion chromatography method for the simultaneous detection of amino acids and sugars was achieved with two valves after injection without alcohol interference. The method had a mean correlation coefficient of >0.99 and a repeatability of 0.92%-4.30% for eight replicates. The mean recovery of six red wine samples were 97.6%, 96.6%, 96.1%, 95.9%, 97.3% and 96.4% respectively. And this method successfully analyzed the amino acid and sugar contents of six wine samples of different origins.

Recent progress of sample stacking in capillary electrophoresis (2014-2016)

The term "sample stacking" comprises a relatively broad spectrum of techniques that already form an almost inherent part of the methodology of CZE. Their principles are different but the effect is the same: concentration of a diluted analyte into a narrow zone and considerable increase of the method sensitivity. This review brings a survey of papers on electrophoretic sample stacking published approximately since the second quarter of 2014 till the first quarter of 2016. It is organized according to the principles of the stacking methods and includes chapters aimed at the concentration adjustment principle (Kohlrausch stacking), techniques based on pH changes, micellar methods, and other stacking techniques. Not reviewed are papers on transient ITP that are covered by another review in this issue.