Ultra-fast Gas Chromatography Research Articles

Discrimination and screening of volatile metabolites in atractylodis rhizoma from different varieties using headspace solid-phase microextraction-gas chromatography-mass spectrometry and headspace gas chromatography-ion mobility spectrometry, and ultra-fast gas chromatography electronic nose

Atractylodis rhizoma is a common bulk medicinal material with multiple species. Although different varieties of atractylodis rhizoma exhibit variations in their chemical constituents and pharmacological activities, they have not been adequately distinguished due to their similar morphological features. Hence, the purpose of this research is to analyze and characterize the volatile organic compounds (VOCs) in samples of atractylodis rhizoma using multiple techniques and to identify the key differential VOCs among different varieties of atractylodis rhizoma for effective discrimination. The identification of VOCs was carried out using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC–MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), resulting in the identification of 60 and 53 VOCs, respectively. The orthogonal partial least squares discriminant analysis (OPLS-DA) model was employed to screen potential biomarkers and based on the variable importance in projection (VIP ≥ 1.2), 24 VOCs were identified as critical differential compounds. Random forest (RF), K-nearest neighbor (KNN) and back propagation neural network based on genetic algorithm (GA-BPNN) models based on potential volatile markers realized the greater than 90 % discriminant accuracies, which indicates that the obtained key differential VOCs are reliable. At the same time, the aroma characteristics of atractylodis rhizoma were also analyzed by ultra-fast gas chromatography electronic nose (Ultra-fast GC E-nose). This study indicated that the integration of HS-SPME-GC–MS, HS-GC-IMS and ultra-fast GC E-nose with chemometrics can comprehensively reflect the differences of VOCs in atractylodis rhizoma samples from different varieties, which will be a prospective tool for variety discrimination of atractylodis rhizoma.

PSXI-11 Oxidation Analysis on Chicken Meat Meals Composition, Aromatics, and Palatability: A Novel Aromatic Palatability Trial Utilizing Labrador Retrievers, Hercules Enose Ufgc, Spme, and Broad Spectrum Gcms

Abstract Even the highest quality ingredients undergo oxidative stresses during manufacturing processes, increasing the nutrition delivery challenges facing large-scale feed manufacturing. In this study we investigate the impact of increasing peroxide values (PV) in the chemical composition in rendered chicken meal (CM) and chicken by-product meal (CB). To determine canine acceptance, working Labrador Retrievers (20 male; 20 female) were used in a preliminary novel aromatic palatability test as well as a traditional two-pan palatability test. PV sample levels ranged from < 10-200 (CB or CM Sample identification: 1.~ < 10, 2.~20-50, 3.~50-100, 4.~100-200). Results indicate that dogs preferred reduced peroxide values in both aromatic (p= < 0.05) and traditional 2-pan palatability trials (p= < 0.05). Preference testing results correlated with extensive physical and chemical data obtained using a Heracles Electronic Nose ultra-fast gas chromatography (UFGC), solid-phase micro-extraction (SPME), and gas chromatography-mass spectrometry (GC-MS). The broad-spectrum analysis utilized solid-phase micro-extraction (SPME) and gas chromatography-mass spectrometry (GC-MS) to identify 177 nonpolar compounds, 340 polar compounds, and 457 volatile compounds. The overall composition did not vary; however, individual compounds had strong linear correlations with peroxide value. In chicken by-product meal samples, 38 compounds were linearly correlated; in chicken meals, 27 compounds were identified (r2>0.90). These data: 1) introduces novel quality control markers for further research and showcases the potential for greater accuracy by developing product specific markers; 2) confirms that the chemical differentiation between peroxide values went beyond lipid oxidation and highlighted multiple compounds of interest for further study; and 3) emphasizes greater levels of peroxide in pet foods have unfavorable palatability. This research was funded by the Fats and Protein Research Foundation.

The Effect of Berry Pomace on Quality Changes of Beef Patties during Refrigerated Storage

This study aims to evaluate the ability of raspberry and blackberry pomace to inhibit lipid oxidation and prolong the refrigerated storage of beef patties. Berry pomace was incorporated into beef patties at the concentration of 1, 3, and 5%. Packed patties were stored for 9 days at 4 °C temperature and the quality of the meat was evaluated on the 0, 3rd, 6th, and 9th day. The natural mass loss during storage, the pH as well as the lipid oxidation were evaluated by thiobarbituric acid-reactive substance (TBARS) method. GC was used to determine the amount of fatty acids and e-nose, based on ultrafast gas chromatography, was used for the determination of volatile organic compounds in beef patties before and after the storage. The highest mass loss during refrigerated storage was observed in the control beef patties, while the berry pomace absorbed water and reduced the loss. The pomace additive influenced the decrease in the patties pH during the storage. Berry pomace can be very effective in relation to lipid oxidation, and as little as 1% of berry pomace influenced the decrease in the TBAR’s values in the patties stored for nine days by 3.06 and 2.42 times, depending on the pomace compared to the control patties. The use of berry pomace in meat products can reduce lipid oxidation, increase their fiber content and act as a thickener, as well as contribute to the usage of agri-food by-products.

Analysis of biodiesel-diesel blends: Does ultrafast gas chromatography provide for similar separation in a fraction of the time?

Ultrafast gas chromatography (UFGC) using a moderately polar column was compared to traditional gas chromatography (GC) for evaluation of biodiesel-diesel blended fuels. Several biodiesel feedstocks (soybean, tallow, canola, palm, camelina) and concentrations (1–20%) were evaluated, with specific attention to the separation of fatty acid methyl esters (FAMEs) from the biodiesel component. UFGC is compared to traditional GC using a similar column chemistry. Principal component analysis (PCA) is performed to identify clustering based on feedstock and concentration. UFGC proves an effective and fast technique, comparable to traditional GC, for the analysis of biodiesel-diesel blended fuels.

Chromatographic fingerprint application possibilities in food authentication

The aim of the study was to compare the effectiveness of the use of low-peak chromatographic fingerprints for the differentiation of various food products. Three groups of unprocessed products (mushrooms, hazelnuts and tomatoes), food preparations (bread, dried herbs and tomato juice) and alcoholic beverages (vodka and two types of blended whiskey) were examined. A commercial electronic nose based on ultrafast gas chromatography (acquisition time 90 s) with a flame ionization detector was used for the research. Static headspace was used as a green procedure to extract volatile compounds without modifying the food matrix. Individual extraction conditions were used for each product group. Similarities and differences between profiles were analyzed by simple Principal Components Analysis. The similarity rating was determined using the Euclidean distances. Global model was built for recognition chromatographic fingerprints of food samples. The best recognition results were 100% and 89% for tomato juices, spices, separate champignon elements and hazelnuts. On the other hand, the worst recognition results were 56% and 77% for breads and strong alcoholic beverages.

Application of gas chromatography-ion mobility spectrometry (GC-IMS) and ultrafast gas chromatography electronic-nose (uf-GC E-nose) to distinguish four Chinese freshwater fishes atboth raw and cooked status.

The volatile organic compounds (VOCs) in four Chinese freshwater fishes (i.e., Hypophthalmichthys molitrix (H), Aristichthys nobilis (A), Lateolabrax japonicus (L), Parabramis pekinensis (P)) were separated using gas chromatography-ion mobility spectrometry (GC-IMS) and ultrafast gas chromatography electronic-nose (uf-GC E-nose). Principal component analysis (PCA) was applied to distinguish the VOCs identified from the four freshwater fishes in both raw and cooked states. Twenty compounds were identified from the spectral database of GC-IMS, including five aldehydes, eight alcohols, six ketones, and three esters. In addition, using GC E-nose, 32 compounds were isolated by the first column MTX-5, and 24 compounds were isolated by the second column MXT-1701. PCA results showed that the four fishes could be well discriminated against. The odor profiles of raw and cooked fishes were clearly different. This study demonstrated that specific signals provided from GC-IMS could differentiate freshwater fishes. GC-IMS and uf-GC E-nose could be developed further to distinguish aquatic products based on VOCs. PRACTICAL APPLICATIONS: Two new methods, gas chromatography-ion mobility spectrometry (GC-IMS) and ultrafast gas chromatography electronic-nose (uf-GC E-nose), were used to analyze the volatile organic compounds (VOCs) in four Chinese freshwater fishes at raw and cooked status. GC-IMS has the characteristics of fast detection speed and high sensitivity. The accuracy of the qualitative analysis of the compounds is better with GC-IMS (larger data volume, leading to a better in-depth statistical analysis). Uf-GC E-nose could provide a nondestructive, fast, relatively low cost, and trustworthy way for flavor analysis. According to the techniques, the established fingerprints of VOCs provided an additional tool for food analysis.

Identification of metabolic markers in patients with type 2 Diabetes by Ultrafast gas chromatography coupled to electronic nose. A pilot study.

Metabolomics is a potential tool for the discovery of new biomarkers in the early diagnosis of diseases. An ultra-fast gas chromatography system equipped to an electronic nose detector (FGC eNose) was used to identify the metabolomic profile of Volatile Organic Compounds (VOCs) in type 2 diabetes (T2D) urine from Mexican population. A cross-sectional, comparative, and clinical study with translational approach was performed. We recruited twenty T2D patients and twenty-one healthy subjects. Urine samples were taken and analyzed by FGC eNose. Eighty-eight compounds were identified through Kovats's indexes. A natural variation of 30% between the metabolites, expressed by study groups, was observed in Principal Component 1 and 2 with a significant difference (p < 0.001). The model, performed through a Canonical Analysis of Principal coordinated (CAP), allowed a correct classification of 84.6% between healthy and T2D patients, with a 15.4% error. The metabolites 2-propenal, 2-propanol, butane- 2,3-dione and 2-methylpropanal, were increased in patients with T2D, and they were strongly correlated with discrimination between clinically healthy people and T2D patients. This study identified metabolites in urine through FGC eNose that can be used as biomarkers in the identification of T2D patients. However, more studies are needed for its implementation in clinical practice.

Supplemental linseed oil and antioxidants affect fatty acid composition, oxidation and colour stability of frozen pork

The aim of this study was to evaluate the influence of dietary linseed oil and antioxidants on the quality of fresh and frozen pork neck stored at -20 °C for six and 12 months. Polish Landrace x Duroc pigs were fed a standard diet (C), a diet supplemented with 3% linseed oil (L1), or a diet with 3% of linseed oil, 1 mg organic selenium (SE)/kg, and 100 mg vitamin E/kg (L2). Chemical components, fatty acid profile and vitamin E content were determined in the fresh meat. Colour, pH and change in the profiles of certain volatile compounds (alcohols, aldehydes, ketones, and esters) were monitored during frozen storage. An electronic nose technique, which was based on ultra-fast gas chromatography, was used to evaluate changes in the profiles of the volatile compounds. After six months of frozen storage, oxidative processes were slower and similar in groups L1 and L2, but less so in meat from C. In pork that was stored for six months, lipid oxidation was not affected by supplementation only with linseed oil (L1). After 12 months of frozen storage, a reduced rate of increase in alcohols, aldehydes and ketones was observed in pork from L2 relative to L1 and C. Lipid oxidation processes in long-stored frozen pork neck were inhibited by the addition of antioxidants to L2. However, a total colour change (ΔE*) of the pork from L1 and L2 was found during storage, which might influence consumers’ decisions to purchase the product.Keywords: colour, fatty acids, freezing, meat quality, volatile components

Antioxidant compound screening and chemical composition of sweet ginger (Alpinia coriandriodora D. Fang) essential oil and the mechanism of scavenging radicals.

The chemical components of an edible spice, sweet ginger (Alpinia coriandriodora D. Fang) essential oil (AEO) were identified by an ultra-fast gas chromatography electronic nose (E-nose) and the main components were β-pinene (27.9%), 1,8-cineole (17.3%), p-cymene (13.5%), camphene (7.3%), myrcene (5.4%), and pseudolimonene (4.3%). The antioxidant activity of each component was evaluated and the mechanisms of scavenging free radical were studied by E-nose combined with chemical methodology. Decanal and α-copaene in AEO showed strong scavenging activities against DPPH radical, and the scavenging rates were over 85%. Decanal had a strong scavenging activity for ABTS radical and the scavenging rate was more than 60%. Similarly, terpinen-4-ol and eugenol had strong scavenging abilities to OH radical and the scavenging rates were more than 50%. Gas chromatography-mass spectrography results showed that it was feasible to identify the chemical components of essential oil by E-nose, and the similarity reached 88.9%. PRACTICAL APPLICATIONS: Many essential oils have antioxidant activities and can be used in functional foods. In the present work, the antioxidant active components in AEO were identified and screened by ultra-fast GC E-nose. We aimed to target the components with strong antioxidant activity quickly and efficiently through the analysis of the reaction process of DPPH, ABTS and OH radicals with a high scavenging rate in a short time. These results indicate that ultra-fast GC E-nose can be used to screen the antioxidant active components in the essential oil.

Evaluation of antioxidant active ingredients of spikenard essential oil by ultra-fast gas chromatography electronic nose and radical scavenging mechanism

As a new rapid detection technology, ultra-fast gas chromatography electronic nose (E-nose) can accurately distinguish and identify different odor ingredients based on the retention index and data processing system in a short time. The chemical components of spikenard (Nardostachys chinensis) essential oil (SEO) were detected by E-nose and verified by GC–MS with 94 % accuracy. Combining E-nose with traditional chemical methodology including E-nose-DPPH, E-nose-ABTS and E-nose−OH were used to quickly evaluate the antioxidant activity of each component of SEO. The results showed that the main components of SEO were calarene, β-maaliene, valerena-4,7(11)-diene, aristolene, γ-terpinene, and seychellene. Furthermore, SEO showed the best scavenging ability in ABTS than DPPH or OH radicals, and the highest scavenging rates are 95.0 % for ABTS, 72.4 % for DPPH and 73.0 % for OH radical, respectively. Among all ingredients of SEO, β-maaliene (70.6 %, 52.3 %, 26.4 %), calarene (69.5 %, 41.6 %, 22.5 %), valerena-4,7(11)-diene (78.1 %, 46.2 %, 6.4 %) and β-cadinene (78.8 %, 51.4 %, 7.1 %) have scavenging effects for ABTS, DPPH and OH radicals.

Antioxidant activity screening and chemical constituents of the essential oil from rosemary by ultra-fast GC electronic nose coupled with chemical methodology.

Traditional chemical methods were mainly used to evaluate the total antioxidant activity of essential oils. How to determine the bioactivity of each compound in mixtures is an interesting research topic. Nowadays, an ultra-fast gas chromatography electronic nose (E-nose) has been gradually used in the detection of volatile compounds, but the screening of the active components of essential oils has not been reported. E-nose coupled with chemical methodology was established using the essential oil from rosemary (EOR) as a specific application example. The proposed method can both identify the chemical constituents of EOR and quickly screen the antioxidant by comparing the change of chromatographic peak area of every component in EOR before and after reaction with free radicals. Among all chemical constituents in EOR, verbenone, eucalyptol and o-cymene showed the strongest scavenging abilities in 1,1'-diphenyl-2-picrylhydrazine (DPPH·), 2,2'-azino-bis(3-ethyl-benzothiazoline-6-sulphonate) (ABTS·+ ) and hydroxyl (·OH) radicals, respectively, with scavenging rates of 67.9%, 39.5%, and 69.9%. The reliability and feasibility of using E-nose to identify chemical constituents of EOR were verified by gas chromatography-tandem mass spectrometry (GC-MS/MS). The GC-MS/MS results showed that the main components of EOR were α-pinene (422.2 μg g-1 ), p-cymene (208.4 μg g-1 ), camphor (203.5 μg g-1 ), verbenone (160.2 μg g-1 ), and eucalyptol (129.1 μg g-1 ). The E-nose methods can be used as a complementary method to traditional spectrophotometric techniques. Furthermore, this study will be of great significance for the rapid screening of antioxidant active components in essential oils from natural products. © 2020 Society of Chemical Industry.

Ultrafast gas chromatography coupled to electronic nose to identify volatile biomarkers in exhaled breath from chronic obstructive pulmonary disease patients: A pilot study.

An analytical method to identify volatile organic compounds (VOCs) in the exhaled breath from patients with a diagnosis of chronic obstructive pulmonary disease (COPD) using a ultrafast gas chromatography system equipped with an electronic nose detector (FGC eNose) has been developed. A prospective study was performed in 23 COPD patients and 33 healthy volunteers; exhalation breathing tests were performed with Tedlar bags. Each sample was analyzed by FCG eNose and the identification of VOCs was based on the Kovats index. Raw data were reduced by principal component analysis (PCA) and canonical discriminant analysis [canonical analysis of principal coordinates (CAP)]. The FCG eNose technology was able to identify 17 VOCs that distinguish COPD patients from healthy volunteers. At all stages of PCA and CAP the discrimination between groups was obvious. Chemical prints were correctly classified up to 82.2%, and were matched with 78.9% of the VOCs detected in the exhaled breath samples. Receiver operating characteristic curve analysis indicated the sensitivity and specificity to be 96% and 91%, respectively. This pilot study demonstrates that FGC eNose is a useful tool to identify VOCs as biomarkers in exhaled breath from COPD patients. Further studies should be performed to enhance the clinical relevance of this quick and ease methodology for COPD diagnosis.

Discrimination of Cocoa Liquors Based on Their Odor Fingerprint: a Fast GC Electronic Nose Suitability Study

With the rising interest by consumers for high-quality cocoa products from a clear geographical origin, a rapid analytical method for quality control, authenticity and traceability assessment is of paramount importance. However, the complex mixture of volatiles present in cocoa liquor, the main ingredient for the chocolate production, complicates reaching this purpose. Hence, an analytical fingerprint approach using advanced electronic nose (E-nose) technology may offer a suitable technique. This study aimed to verify the suitability of an E-nose based on ultra-fast gas chromatography (GC) for the rapid discrimination between cocoa liquors from different origins. Fourteen cocoa liquors, produced of cocoa beans from ten different geographical origins, were analyzed. The obtained odor fingerprints were investigated using principal component analysis (PCA) which successfully discriminated most cocoa liquors, within one continent, according to their geographical origin. Besides, discriminant factor analysis (DFA) showed the possibility to differentiate between bulk and fine cocoa. Further tentative identification of predominant volatile compounds allowed the detection of compounds within a wide range of chemical classes occurring in cocoa products, such as acids, alcohols, aldehydes, ketones, esters, pyrazines, pyrones, and pyrroles. Most odorant compounds were previously described in literature as key volatiles in cocoa flavor, notable examples are acetic acid, 2-heptanol, 2/3-methylbutanal, acetophenone, isoamyl acetate, tetramethylpyrazine, maltol, and 2-acetyl-1-pyrroline. This study proves for the first time the usefulness of the GC E-nose for effective and rapid aroma profiling and discrimination between single origin cocoa liquors, which can be easily applied in the cocoa industry.

Novel analytical method for detection of orange juice adulteration based on ultra-fast gas chromatography

The food authenticity assessment is an increasingly important issue in food quality and safety. The application of an electronic nose based on ultra-fast gas chromatography technique enables rapid analysis of the volatile compounds from food samples. Due to the fact that this technique provides chemical profiling of natural products, it can be a powerful tool for authentication in combination with chemometrics. In this article, a methodology for classification of Not From Concentrate (NFC) juices was presented. During research samples of 100% orange juice, 100% apple juice, as well as mixtures of these juices with known percentage of base juices were tested. Classification of juice samples was carried out using unsupervised and supervised statistical methods. As chemometric methods, Hierarchical Cluster Analysis, Classification Tree, Naïve Bayes, Neural Network, and Random Forest classifiers were used. The ultra-fast GC technique coupled with supervised statistical methods allowed to distinguish juice samples containing only 1.0% of impurities. The developed methodology is a promising analytical tool to ensure the authenticity and good quality of juices.Graphical abstract

Rapid assessment of the authenticity of limequat fruit using the electronic nose and gas chromatography coupled with mass spectrometry

Citrus fruits are very popular food products. There are many species and varieties of them. There are also documented cases of some citrus fruits causing a severe allergic reaction. Some species of the citrus fruits, especially hybrid ones show a reduced allergenic effect due to the lack of seeds. There is a need for rapid methods for evaluation of citrus’ botanical origin. During research, the headspace of three citrus fruits Citrus Aurantifolia, Citrus japonica, and Citrus × floridana was analysed using electronic nose based on ultrafast gas chromatography and gas chromatography with mass spectrometry. In the paper, two approaches were compared. The usefulness of an electronic nose to control the quality of hybrids was demonstrated. The results obtained during ultrafast gas chromatography analyses were subjected to statistical analysis. Four chemometric methods namely: principal component analysis (PCA), discriminant function analysis (DFA), soft independent modeling of class analogies (SIMCA), statistical quality control (SQC) were used to distinguish between limequat and its parent fruits. Electronic nose combined with chemometrics is a novel analytical tool for hybrid fruits’ classification due to their botanical origin. It can supplement established techniques by providing results in a short time and at a low cost.Graphical abstract

Analysis of biodiesel-diesel blends using ultrafast gas chromatography (UFGC) and chemometric methods: Extending ASTM D7798 to biodiesel

Ultrafast gas chromatography (UFGC) along with supervised and unsupervised chemometric methods were utilized for evaluation of biodiesel-diesel blended fuels. A variety of biodiesel feedstocks (soybean, tallow, canola, safflower, sunflower, camelina, flaxseed, etc.) and concentrations (1–20%) were evaluated. The method, which uses a short nonpolar column, falls within ASTM D7798 requirements for diesel and extends the method to include biodiesel-diesel blended fuels. Using Principal Components Analysis (PCA), samples clustered based on concentration and diesel type, and differences in plant and animal feedstocks were apparent. Biodiesel concentration was accurately assessed using Partial Least Squares (PLS) on a training set for B0–B20, while predictions were made with some success on a set of commercial and lab unknowns. k Nearest Neighbors (kNN) was used to describe and predict concentration, plant versus animal feedstock, and to identify biodiesel blends. The combination of chemometric methods alongside UFGC proves an effective and fast technique for the analysis of biodiesel source and composition in biodiesel-diesel blended fuels.

Classification of Polish wines by application of ultra-fast gas chromatography

The potential of ultra-fast gas chromatography (GC) combined with chemometric analysis for classification of wine originating from Poland according to the variety of grape used for production was investigated. A total of 44 Polish wine samples differing in the type of grape (and grape growth region) used for the production as well as parameters of the fermentation process, alcohol content, sweetness, and others which characterize wine samples were analysed. The selected features coming from ultra-fast GC analysis were subsequently used as inputs for both principal component analysis (PCA) and supervised machine learning. Using the proposed classification algorithm, it was possible to classify white and red wines according to the variety of grape used for production with a 98.7 and 98.2% accuracy, respectively. The model was characterized by good recall and area under receiver operating characteristic which was 1.000 for white wines and 0.992 for red wines. Cuvee wines (made from various types of grapes) were also successfully classified which leads to the conclusion that the proposed classification method can be used not only to differentiate between wines made from different grapes but also to detect possible adulterations, provided known; non-adulterated samples are available as a reference. The model was also used to classify wine samples based on other features, such as the geographic region in which the vineyard is situated, type of yeast used, the temperature of fermentation, sweetness, etc. In all cases, a high classification accuracy (in most cases > 90%) was achieved. The obtained results could be applied in the wine industry.

Oxidation processes of &lt;i&gt;Longissimus dorsi&lt;/i&gt; from pigs supplemented with linseed oil and antioxidants

The aim of this study was to determine the effects of pig fodder supplementation on lipid oxidation of Longissimus dorsi (L. dorsi ) after frozen storage at -20 °C ± 1 °C for nine months. Fodder additives included 3% linseed oil (L1) or 3% linseed oil and antioxidants containing 100 mg vitamin E/kg and 1 mg organic selenium/kg (L2). The oxidation processes were evaluated by measuring thiobarbituric acid reactive substances (TBARS) and analyses of a profile of volatile organic compounds (VOC). The VOC were determined using an electronic nose based on ultra-fast gas chromatography. The level of TBARS for diets was 1.88 ± 0.52 to 2.30 ± 1.10 mg malondialdehyde/kg of meat. The results indicated that the diet of pigs from L1 and L2 groups had no impact on the TBARS value of L. dorsi pork frozen for nine months. On the other hand, aldehydes, which are regarded as compounds characteristic of oxidation processes, were identified in all samples. Volatile aldehydes contributed approximately 10%, 12%, and 15% of total detected volatiles for L2, L1, and the control group, respectively. Moreover, the data showed that propanal and benzeneacetaldehyde were at the same level, regardless of the animal’s diet, which is in accordance with the TBARS level. These volatile aldehydes resulted from the oxidation of polyunsaturated fatty acids (PUFAs) and may be considered indicators of lipid oxidation for meat enriched with PUFAs. The results show that supplementation of the pigs’ diet with linseed oil (L1 group), which is a source of PUFAs, is recommended for meat intended for long-term freezing storage. However, supplementation with antioxidants is unnecessary, because it has no effect on lipid oxidation of L. dorsi pork after long-term freezing storage. Keywords : Animal’s diet, frozen storage, lipid oxidation, volatile organic compounds

Rapid and sensitive method for detecting adulterants in gasoline using ultra-fast gas chromatography and Partial Least Square Discriminant Analysis

In the last years, the Brazilian Fuel Quality Monitoring Program drastically reduced the number of analyzed fuel samples as consequence of the current economic crisis in the country. The impoverishment of the monitoring program may lead to an increase in cases of gasoline adulteration, nonetheless, it also strengthens the search for faster and less costly methodologies for the fuel quality monitoring. Thus, this study aimed the development of a rapid analytical method to detect the adulteration of gasoline with organic solvents through ultra-fast gas chromatography with flame ionization detector (UFGC-FID) associated with the supervised pattern recognition method, Partial Least Square Discriminant Analysis (PLS-DA). The sample set consisted of 171 Brazilian common gasoline (i.e., with ethanol in its composition) and 171 adulterated gasoline prepared in laboratory using 19 different solvents in the concentration range of 2–10% (v/v). The chromatographic method required only 2.85 min and the chromatograms presented 125 peaks on average. The PLS-DA model was developed with 3 latent variables and provided correlation coefficients close to 0.99 and correct discrimination of 100% of calibration and validation samples. Therefore, the developed UFGC-FID/PLS-DA method provided a sensitive, fast and automated alternative method for the detection of adulterants in the monitoring of gasoline quality.

Poultry meat freshness evaluation using electronic nose technology and ultra-fast gas chromatography

To ensure that chicken meat products are safe to consume, it is important to be able to reliably determine its shelf-life. To assess the applicability of ultra-fast gas chromatography and electronic nose technology in evaluation of poultry, an analysis of the headspace of ground chicken meat samples refrigerated over a period of 7 days was performed. Chemometric techniques were used to mine additional information from a multiparametric data set. As a reference, sensory evaluation was also conducted, and several volatile chemical compounds that can potentially be used as poultry meat decomposition indicators were identified. The obtained results suggest the possibility of using both techniques to supplement the established methods of chicken meat quality assessment.Graphical abstract