Food and Beverage Analysis

The durian fruit is notorious for its unpalatable aroma, and yet the fruit is incredibly popular throughout Southeast Asia and amongst travellers. Holding the title of “the world’s smelliest fruit” attracts attention including that of Martin Steinhaus from the Aroma Research Group at the Deutsche Forschungsanstalt für Lebensmittelchemie (German Research Center for Food Chemistry). He spoke to The Column about his group’s research into the compounds responsible for the fruit’s uniquely unpleasant aroma.

Polyphenols are a well-known group of antioxidants widely diffused as secondary metabolites in plants, vegetables, and fruit. The Column spoke to Nicola Marchetti from the Department of Chemistry and Pharmaceutical Sciences at the University of Ferrara in Ferrara, Italy, about his research into the characterization of polyphenols in red chicory using high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS).

Monitoring lipid oxidation during the shelf life of lipid-containing food emulsions, such as mayonnaise, is challenging. It is, however, essential for the development of improved, consumer-preferred products. Determining the nonvolatile lipid oxidation products (NONVOLLOPS), the precursor compounds for rancidity, is required to determine the effectiveness of product stabilization technologies. A method based on normal-phase liquid chromatography with atmospheric pressure photo ionization-mass spectrometry (LC–APPI-MS) was developed for this purpose. The inclusion of a size-exclusion chromatography (SEC) step was needed to remove interfering diacylglycerides and free fatty acids from the samples. The combined SEC and normal-phase LC–APPI-MS method allowed the identification of a wide range of oxidized species including hydroperoxides, oxo-2½ glycerides, epoxides, and other oxidized species. The method was found to be more suitable for the analysis of large sample sets.

There is a growing interest in polyphenols because of their noticeable antioxidant properties and their potential contribution to the defence against oxidative stress and protection against cardiovascular diseases and cancers. Oscar Núñez from the Department of Chemical Engineering and Analytical Chemistry at the University of Barcelona in Barcelona, Spain, has been working since 2010 in the analysis of polyphenols by capillary electrophoresis (CE), liquid chromatography (LC), mass spectrometry (MS), and chemometric techniques to achieve the characterization, classification, and authentication of natural products in the prevention of frauds. He recently spoke to The Column about this research.

Adulteration is a significant problem for the olive oil industry because of the product’s high value. With the demand for olive oil expected to rise significantly, this problem is set to increase. Reliable and accurate determinations of olive oil adulteration are therefore required to maintain product integrity. This article introduces a principle component analysis‑based approach that uses data obtained by high performance liquid chromatography (HPLC)-charged aerosol detection (CAD) to determine extra virgin olive oil adulteration by common vegetable oil adulterants. Using only sample dilution and analysis, the method could be used to assess olive oil quality relative to pomace oil.

Liquid Chromatography and High-Resolution Mass Spectrometry In food analysis, HPLC and triple-quadrupole mass spectrometry are established techniques. Jon Wong of the Center for Food Safety and Applied Nutrition at the U.S. Food and Drug Administration discusses why his agency and others have been developing food analysis methods using UHPLC and HRMS.

In this study, an empirical assessment of summation integration (using the lowest baseline point in user-defined tR windows) was conducted involving 490 low-pressure GC–MS/MS analyses of 70 pesticides in 10 common fruits and vegetables over the course of 10 days.

An automated method for determination of water in liquid sweeteners was developed using headspace gas chromatography (GC) and ionic liquid-based capillary GC columns. This method allowed for the rapid determination of water with minimal sample pretreatment. In addition to providing fast analysis time for the samples, the headspace GC method was found to be accurate and precise for the measurement of water in 16 liquid sweeteners. This method was shown to be widely applicable for sugar and sugar-free sweeteners and more accurate than Karl Fischer titration.

Speciation analysis of elemental contaminants in food and beverages has received a lot of attention in recent years. Recent regulations limit inorganic arsenic, taking into account that arsenic toxicity is dependent on the species present. Thus, the analysis procedure needs to be able to differentiate inorganic from organic arsenic forms. Liquid chromatography–inductively coupled plasma–mass spectrometry (LC–ICP-MS) is commonly used for the separation and detection of arsenic species, with the most widely used implementation based on ion exchange and characterized by relatively long run times. Testing of increasing sample numbers means that analysis speed becomes a focal point for potential improvements. We developed a method based on ion interaction chromatography, allowing a reduction in run times to

As a result of the rapid growth of the cannabis industry, many testing laboratories are looking for efficient, reliable, and cost-effective analytical methods to analyze chemical residues, such as pesticides, mycotoxins, solvent residues, terpenes, and heavy metals, as well as cannabinoid concentration in cannabis-infused edibles and beverages. In this article, QuEChERS (quick, easy, cheap, effective, rugged, and safe), a sample preparation technique widely adopted in the food testing industry, is introduced to the discipline of forensic testing as a viable method for the extraction of pesticides and cannabinoids in various complex sample matrices. The claimed amounts of cannabinoids versus the actual amounts are compared, as well as the pesticide residue levels in edible and beverage samples.

A method based on salting-out assisted liquid–liquid extraction for the analysis of α-dicarbonyls in wines was developed. The sample preparation procedure consists of a single step, involving the simultaneous extraction and derivatization of the analytes using an o-phenylenediamine–acetonitrile solution with sodium chloride as the salting-out agent. The obtained organic phase is collected and directly analyzed by liquid chromatography with spectrophotometric detection. The studied α-dicarbonyls were determined in eight wines. The developed methodology substantially reduces the complexity of the sample matrix, which is a very important aspect in routine analysis, especially to ensure long-lasting and reliable functioning of the chromatographic systems, while being a new and attractive methodology for the analysis of α-dicarbonyls.

Accurate quantification of sugars in saline solution is now possible using a new high performance liquid chromatography (HPLC) method. The Column spoke to Abdelrahman Saleh Zaky from the School of Biosciences at the University of Nottingham (Nottingham, UK) about this method.

Food carbohydrate content is routinely analyzed to ensure food quality and taste. Over the years many analytical techniques, including thin-layer chromatography (TLC), enzymatic analysis, and gas liquid chromatography (GLC), have been developed that allow qualitative and quantitative analysis of sugars, organic acids, and alcohol in food. Amongst these, ion‑moderated partitioning high performance liquid chromatography (HPLC) has emerged as a very valuable tool and has been used in thousands of published studies. This article describes the various considerations for selecting and optimizing the use of ion-moderated partitioning HPLC analytical columns for carbohydrate analysis in various types of food samples.

The growing popularity of extra virgin olive oil (EVOO), thanks in part to its presumed health benefits, has resulted in an increased incidence of product adulteration to achieve higher financial gains. This adulteration, through dilution with less expensive oils, has created demand for product authenticity testing. Olive oil testing based on traditional methods is slow, labour-intensive, and requires large amounts of organic solvents. This article reviews the challenges in the accurate analysis of olive oil and discusses new methods that can improve this testing.

Monitoring lipid oxidation during the shelf life of lipid-containing food emulsions, such as mayonnaise, is challenging. It is, however, essential for the development of improved, consumer-preferred products. Determining the nonvolatile lipid oxidation products (NONVOLLOPS), the precursor compounds for rancidity, is required to determine the effectiveness of product stabilization technologies. A method based on normal-phase liquid chromatography with atmospheric pressure photo ionization-mass spectrometry (LC–APPI-MS) was developed for this purpose. The inclusion of a size-exclusion chromatography (SEC) step was needed to remove interfering diacylglycerides and free fatty acids from the samples. The combined SEC and normal-phase LC–APPI-MS method allowed the identification of a wide range of oxidized species including hydroperoxides, oxo-2½ glycerides, epoxides, and other oxidized species. The method was found to be more suitable for the analysis of large sample sets. The relative levels of NONVOLLOPS from bo

Fresh fruit and vegetables have a limited shelf life and so there is a need to ensure that the products reach the shelf in a timely manner and with as little spoilage as possible. Volatile organic compounds (VOCs) are an easily accessible way of monitoring changes in fresh produce. Hilary J. Rogers and Carsten T. Müller from the School of Biosciences at Cardiff University, Cardiff, Wales, UK, investigate these VOCs in fruit and vegetables using gas chromatography–mass spectrometry (GC–MS). They recently spoke to The Column about this research.

A method to determine the quality of olive oil has been developed using a novel atmospheric pressure chemical ionization (APCI) source in combination with gas chromatography (GC) coupled to hybrid quadrupole time-of-flight mass spectrometry (QTOF-MS) and a metabolomics strategy.

Food testing laboratories worldwide are responsible for checking the presence of regulated pesticide residues on food products because these chemicals can be harmful to health and the environment. These laboratories have traditionally relied on gas chromatography coupled with mass spectrometry (GC–MS) for rapid and reliable pesticide detection in large sample numbers. However, changing regulations and increasingly diverse pesticides are driving the need for alternative liquid chromatography tandem mass spectrometry (LC–MS/MS)- based methods for comprehensive screening.

This article describes the application of liquid chromatography tandem mass spectrometry (LC–MS/MS) and enhanced multiple reaction monitoring (MRM) spectrum libraries for multi-pesticide residue analysis. Using these methods, a high number of fragment ion transitions of target compounds can be examined to increase specificity and reporting confidence, reducing the risk of false positive or false negative detection.

The 8th International Symposium on Recent Advances in Food Analysis (RAFA 2017) will take place in Prague, Czech Republic, on 7–10 November 2017.

In this study, general extract screening of food storage materials was done with nontargeted analytical methods to understand what analytes could potentially leach into food or beverages. GC and mass spectral deconvolution effectively separated analytes within the complex mixture and TOF-MS provided full mass range spectral data for identification. This workflow can be used for confident characterization of components present as extractables from food packaging materials.

LCGC spoke to Rudolf Krska from the University of Natural Resources and Life Sciences in Vienna, Austria, about the latest analytical techniques and challenges facing analysts involved in the evolving field of mycotoxin analysis.

Honey is a high-value commodity, whose quality is defined both by its botanical and geographical origin. This generates a strong consumer demand for certain, premium-priced products, which have become the target for adulterations. A useful tool to detect the addition of sugar to honey products is based on the well-documented difference in δ13C values between C3 (natural honey) and C4 (added sugar) plants. Coupling high performance liquid chromatography (HPLC) with isotope ratio mass spectrometry (LC–IRMS) has the unrivaled advantage of the simultaneous determination of δ13C values from glucose, fructose, di-, tri-, and oligo-saccharides, allowing the detection of more sophisticated honey adulteration with a simple user-friendly analytical system.

This study shows that the organic compounds giving rise to the flavour of a variety of beverages can be identified by high-capacity sorptive extraction using PDMS probes, with analysis by thermal desorption–GC–MS.

Traditional extraction methods for food samples, such as liquid-liquid extraction and Soxhlet extraction, are often time-consuming and require large amounts of organic solvents. Therefore, one of the objectives of analytical food safety studies currently has been the development of new extraction techniques that can improve the accuracy and precision of analytical results and simplify the analytical procedure.