Sequential thin film-solid phase microextraction as a new strategy for addressing displacement and saturation effects in food analysis

Automated sequential SPME addressing the displacement effect in food samples

The displacement effect can be an issue for the quantitation of analytes with low affinity towards the extraction phase in solid-phase microextraction (SPME) for food samples that have low level of binding matrix or high level of hydrophobic compounds. In this communication, automated sequential SPME-GC-MS strategy was developed for addressing the displacement issue. The SPME thin film with PDMS coating was firstly used for the extraction of hydrophobic components in the sample which cause displacement and then SPME fiber with DVB/CAR/PDMS coating was applied in the second step for the extraction of the remain compounds. This new strategy was investigated by using 10 key food odorants as target analytes and tested in commercial beer samples. The results suggested that sequential SPME can decrease the displacement effect and improve the extraction efficiency for polar analytes.

Solid-phase microextraction coupled to comprehensive multidimensional gas chromatography for food analysis

Solid-phase microextraction and comprehensive multidimensional gas chromatography represent two milestone innovations that occurred in the field of separation science in the 1990s. They have a common root in their introduction and have found a perfect coupling in their evolution and applications. This review will focus on food analysis, where the paradigm has changed significantly over time, moving from a targeted analysis, focusing on a limited number of analytes at the time, to a more holistic approach for assessing quality in a larger sense. Indeed, not only some major markers or contaminants are considered, but a large variety of compounds and their possible interaction, giving rise to the field of foodomics. In order to obtain such detailed information and to answer more sophisticated questions related to food quality and authenticity, the use of SPME-GC × GC-MS has become essential for the comprehensive analysis of volatile and semi-volatile analytes. This article provides a critical review of the various applications of SPME-GC × GC in food analysis, emphasizing the crucial role this coupling plays in this field. Additionally, this review dwells on the importance of appropriate data treatment to fully harness the results obtained to draw accurate and meaningful conclusions.

Application of Sorbent-Based Extraction Techniques in Food Analysis

This review presents an outline of the application of the most popular sorbent-based methods in food analysis. Solid-phase extraction (SPE) is discussed based on the analyses of lipids, mycotoxins, pesticide residues, processing contaminants and flavor compounds, whereas solid-phase microextraction (SPME) is discussed having volatile and flavor compounds but also processing contaminants in mind. Apart from these two most popular methods, other techniques, such as stir bar sorptive extraction (SBSE), molecularly imprinted polymers (MIPs), high-capacity sorbent extraction (HCSE), and needle-trap devices (NTD), are outlined. Additionally, novel forms of sorbent-based extraction methods such as thin-film solid-phase microextraction (TF-SPME) are presented. The utility and challenges related to these techniques are discussed in this review. Finally, the directions and need for future studies are addressed.

High throughput and automated solid-phase microextraction and determination by liquid chromatography-mass spectrometry for the analysis of mycotoxins in beer

There is high demand for rapid screening of toxics in food analysis. In this study, a new high-throughput and automated solid-phase microextraction (SPME) system was employed for the sample preparation of mycotoxins in beers. Matrix compatible SPME blades with thin coating layer were used, which significantly decreased the matrix effects in beer samples (≤ 12%). This SPME system allows 96 samples to be processed automatically and simultaneously with average preparation time of 57 s per sample. After sample preparation, the 96-well plate with desorption solution was sealed with a thin film and put into the LC-MS sampler for analysis via positive/negative ESI switching mode. The results also showed good sensitivity (limits of detection between 0.02 and 3 ng/mL) with R²≥ 0.9971, reproducibility (intra- and inter-day ≤ 8% and ≤ 13%, respectively), and accuracy (recoveries between 79% and 121%).

Investigation of Lactone Chiral Enantiomers and Their Contribution to the Aroma of Longjing Tea by Odor Activity Value and S-Curve

Odor activity value (OAV) and S-curve were used to study the content, proportion, and contribution of lactone chiral enantiomers in Longjing tea. A total of 10 enantiomers were identified in this study, among which (S)-(-)-δ-decalactone (45.4-84.4 μg/L), (S)-(-)-γ-decalactone (31.5-109 μg/L), (S)-(-)-γ-nonanolactone (23.4-72.8 μg/L), and (S)-(-)-γ-undecalactone (21.1-56.2 μg/L) presented the highest concentrations. Furthermore, (R)-(+)-γ-nonanolactone (OAV: 2-7), (S)-(-)-γ-nonanolactone (OAV: 1-5), (S)-(-)-δ-decalactone (OAV: 2-4), (R)-(+)-δ-decalactone (OAV: 1-3), and (R)-(+)-γ-undecalactone (OAV: 1-5) were determined as enantiomeric compounds that play an important role in the perceived aroma of Longjing tea. Compared with the aromatic reconstitution (AR), the threshold increased to different degrees after adding γ-nonanolactone, γ-decalactone, δ-decalactone, γ-undecalactone, and their chiral enantiomers. This finding indicated that these compounds exert significant effects on the overall aroma of the AR. The contribution of racemates and chiral enantiomers to the AR threshold and aroma is completely different. In view of the difference between racemic and enantiomers' aroma characteristics in Longjing tea, the analysis and identification of chiral enantiomers are necessary to enrich and improve the accurate analysis of the flavor profile of Longjing tea.

Exploring different high-capacity tools and extraction modes to characterize the aroma of brewed coffee

In the present work, the potential benefit of using multi-cumulative trapping headspace extraction was explored by comparing the results using solid-phase microextraction (SPME) coated with divinylbenzene/carboxen/polydimethylsiloxane and a probe-like tool coated with polydimethylsiloxane. The efficiency of a single 30-min extraction, already explored in previous work, was compared with that of multiple shorter extractions. We evaluated three different conditions, i.e., three repeated extractions for 10 min each from different sample vials (for both the probe-like tool and SPME) or from the same vial (for SPME) containing brewed coffee. The entire study was performed using comprehensive two-dimensional gas chromatography coupled with mass spectrometry. The two-dimensional plots were aligned and integrated using a tile-sum approach before any statistical analysis. A detailed comparison of all the tested conditions was performed on a set of 25 targeted compounds. Although a single 30-min extraction using the probe-like tool provided a significantly higher compound intensity than SPME single extraction, the use of multiple shorter extractions with SPME showed similar results. However, multiple extractions with the probe-like tool showed a greater increase in the number of extracted compounds. Furthermore, an untargeted cross-sample comparison was performed to evaluate the ability of the two tested tools and the different extraction procedures in differentiating between espresso-brewed coffee samples obtained from capsules made of different packaging materials (i.e., compostable capsules, aluminum capsules, aluminum multilayer pack). The highest explained variance was obtained using the probe-like tool and multiple extractions (91.6% compared to 83.9% of the single extraction); nevertheless, SPME multiple extractions showed similar results with 88.3% of variance explained.

Valorisation of Broccoli By-Products: Technological, Sensory and Flavour Properties of Durum Pasta Fortified with Broccoli Leaf Powder

The aim of this study was to evaluate the effect of broccoli leaf powder (BLP) incorporation on the technological properties, sensory quality and volatile organic compounds (VOCs) of durum wheat pasta. Incorporation of BLP increased cooking loss; however, all pasta samples were found to be in the acceptable range of 8 g/100 g. The addition of BLP decreased optimal cooking time and water absorption but increased the swelling index. Firmness and total shearing force decreased with increased BLP content. The obtained pasta was greener than the control, with a higher content of minerals, and an increasing tendency with respect to protein was observed. The VOC profile of enriched pasta was richer and contained compounds typical of broccoli (e.g., dimethyl sulphide), affecting its aroma. The sensory evaluation results indicate that the addition of BLP did not affect the overall acceptance of pasta. Up to 5% BLP content afforded an interesting, more nutritious pasta without compromising its technological and sensory quality.