Application of gas chromatography in food analysis

Integrated Smart Gas Tracking Device with Artificially Tailored Selectivity for Real-Time Monitoring Food Freshness

The real-time monitoring of food freshness in refrigerators is of significant importance in detecting potential food spoiling and preventing serious health issues. One method that is commonly reported and has received substantial attention is the discrimination of food freshness via the tracking of volatile molecules. Nevertheless, the ambient environment of low temperature (normally below 4 °C) and high humidity (90% R.H.), as well as poor selectivity in sensing gas species remain the challenge. In this research, an integrated smart gas-tracking device is designed and fabricated. By applying pump voltage on the yttria-stabilized zirconia (YSZ) membrane, the oxygen concentration in the testing chamber can be manually tailored. Due to the working principle of the sensor following the mixed potential behavior, distinct differences in sensitivity and selectivity are observed for the sensor that operated at different oxygen concentrations. Typically, the sensor gives satisfactory selectivity to H2S, NH3, and C2H5OH at the oxygen concentrations of 10%, 30%, and 40%, respectively. In addition, an acceptable response/recovery rate (within 24 s) is also confirmed. Finally, a refrigerator prototype that includes the smart gas sensor is built, and satisfactory performance in discriminating food freshness status of fresh or semi-fresh is verified for the proposed refrigerator prototype. In conclusion, these aforementioned promising results suggest that the proposed integrated smart gas sensor could be a potential candidate for alarming food spoilage.

Effect of Seawater Curing Agent on the Flavor Profile of Dry-Cured Bacon Determined by Sensory Evaluation, Electronic Nose, and Fatty Composition Analysis

The purpose of this study was to check the applicability of seawater as a natural curing agent by analyzing the difference it causes in the flavor of dry-aged bacon. Pork belly was cured for seven days, and dried and aged for twenty-one days. The curing methods included the following: wet curing with salt in water, dry curing with sea salt, brine curing with brine solution, and bittern curing with bittern solution. The seawater-treated groups showed a lower volatile basic nitrogen value than the sea-salt-treated groups (p < 0.05); dry curing showed a higher thiobarbituric acid reactive substance value than other treatments (p < 0.05). Methyl- and butane- volatile compounds and polyunsaturated fatty acids such as g-linolenic and eicosapentaenoic were the highest in the bittern-cured group, lending it superior results compared to those of the control and other treatments in sensory flavor analyses (cheesy and milky). Therefore, bittern is considered to have significant potential as a food-curing agent.

A polypyrrole-cotton pad sorbent as micro-solid phase extractor enclosed in tea bag envelope for determination of synthetic antioxidants in non-alcoholic beverage products

A polypyrrole (PPy)-cotton pad sorbent enclosed in tea bag envelope was developed and used in micro-solid phase extraction (µ-SPE) for the determination of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). After extraction, the extract was qualified and quantified by a gas chromatograph equipped with a flame ionization detector (GC-FID). Parameters influencing this developed method and the efficiency of µ-SPE were studied and optimized. Under the optimal conditions, the developed method provided good linearity in a concentration range of 0.100-100 µg L^-1 for BHA and 0.050-50 µg L^-1 for BHT, respectively. The limits of detection were 39.27 ± 0.52 ng L^-1 for BHA and 16.96 ± 0.17 ng L^-1 for BHT. Satisfactory relative recoveries of BHA and BHT were achieved in the range from 86.8 ± 1.9 to 117.1 ± 2.3% with acceptable relative standard deviation (RSD) below 8.1%. Good reproducibility was obtained with RSDs < 3.1%, for n = 6. The developed adsorbent is easy to operate, low cost, eco-friendly, reusable, with high extraction efficiency, and was successfully applied in the simultaneous synthetic antioxidant determination of non-alcoholic beverage samples.

Montmorillonite-based polymethacrylate composite monoliths as stationary phase materials for food and pharmaceutical analysis in capillary liquid and gas chromatography

This work relates to the preparation of novel and promising stationary phases containing inorganic-organic composites for capillary liquid and gas chromatography. A naturally occurring montmorillonite was introduced to polymethacrylate monoliths, then used under different conditions of GC and HPLC at the same time. The performance of the columns was evaluated for the separation of alkane and alkylbenzene series in GC and capillary HPLC, respectively. While the bare monoliths failed to separate the model analytes, montmorillonite-based polymethacrylate allowed a full separation of the mixtures with R_s≥1.42. The columns were applied for the determination of myrcene and limonene isomers in the peel extracts of some fruits using GC, and for the analysis of active ingredients including aspirin, vitamin-C, caffeine, and ibuprofen extracted from common drugs using capillary HPLC. In GC, fast separation was achieved in 1.0 min with R_s of 6.53. The columns exhibited the best efficiency for myrcene with 20,900 plates/m. Using the capillary HPLC columns, the active ingredients were resolved in 10 min with R_s≥5.72. The efficiency values located between 12,800-21,700 plates/m in all cases. The developed methods were found to be linear in the range of 0.10-10.0 and 0.20-180 μg/mL for GC and HPLC, respectively. In comparison with commercial columns, the results in GC methods reveal that, despite their much shorter length, the prepared columns proved a faster separation with higher efficiency and comparable detection limits and chromatographic resolution. The prepared HPLC capillaries exposed lower run times and detection limits with comparable efficiency and resolution, and consume fewer samples and mobile phase solvents. The results demonstrate that the montmorillonite-based polymethacrylate composites are applicable as stationary phases for routine analysis and quality control of important fields such as food and pharmaceutical samples.

A review of conventional and rapid analytical techniques coupled with multivariate analysis for origin traceability of soybean

Soybean has developed a reputation as a superfood due to its nutrient profile, health benefits, and versatility. Since 1960, its demand has increased dramatically, going from a mere 17 MMT to almost 358 MMT in the production year 2021/22. These extremely high production rates have led to lower-than-expected product quality, adulteration, illegal trade, deforestation, and other concerns. This necessitates the development of an effective technology to confirm soybean's provenance. This is the first review that investigates current analytical techniques coupled with multivariate analysis for origin traceability of soybeans. The fundamentals of several analytical techniques are presented, assessed, compared, and discussed in terms of their operating specifics, advantages, and shortcomings. Additionally, significance of multivariate analysis in analyzing complex data has also been discussed.

An overview of nutritional profiling in foods: Bioanalytical techniques and useful protocols

Maintaining a nutritious diet is essential for humans if they want to live a healthier life. Several food businesses and food safety organizations play a significant role and offer useful ways for improving nutritional quality that assists consumers in making informed selections. Making poor food choices and consuming unhealthy meals are the main causes of non-communicable diseases (NCDs). Nutritional profiling (NP) models are developed to evaluate the nutritional value, calorie content, and the amount of micronutrients and macronutrients contained in a given food accompanied by additional details on the nutritional anomaly provided by published standard nutrients and nutritional databases. To construct an ideal nutritional model that can facilitate food consumption, bioanalytical methods such as chromatography, microscopic techniques, molecular assays, and metabolomics can be applied. With the use of these technologies, one can learn more about the health advantages of nutrition and how to prevent disease. A wider element of NP is also provided by the developing technologies in the area of nutrition research, such as nanotechnology, proteomics, and microarray technology. In this review, we are focusing on the different bioanalytical techniques and the various protocols of NP and their application and refinement of the models. We have evaluated various NP techniques currently used in the food industry for the detection of different components present in food items.

Naturally Occurring Montmorillonite-Based Polymer Monolith Composites as Stationary Phases for Capillary Liquid and Gas Chromatography

This work is associated with the preparation of capillary chromatographic columns containing inorganic-organic composites comprised of naturally occurring montmorillonite (MMT) clay mineral and polymethacrylate monolithic material. The prepared composites combine the best qualities of both constituents, offering desirable properties for use under the disparate conditions of both GC and HPLC at the same time. The stationary phases were investigated by scanning electron microscopy (SEM), the specific surface area, and thermogravimetric analysis (TGA) and examined in terms of various conditions utilized for GC and HPLC methods. The prepared columns demonstrated an excellent permeability and stability against common chromatographic conditions, such as the eluent type, flow rate, pressure, and temperature. The results confirmed that the addition of small amounts of MMT into the monolith induced significant improvement in the specific surface area, which contributed to the formation of more active sites and enhanced the retention of analytes. The registered column backpressures did not exceed 980 kPa and 16,500 kPa for the prepared GC and HPLC columns, respectively. The prepared columns were subjected to the separation of various interesting compounds possessing different chemistries and polarities, including alkanes, alkylbenzenes, polycyclic aromatic hydrocarbons (PAHs), alcohols, ketones, phenols, some common organic solvents, and isomeric mixtures. Under the optimal conditions, the efficiency of the columns fell between 4900–38,500 plates m−1 for GC and 3400–58,800 plates m−1 for capillary HPLC applications. In all cases, the measured chromatographic resolution was more than 1.38, with excellent an peak symmetry and low tailing factors. In comparison with the most commonly used commercial columns, the polysiloxane open tubular column for GC and silica-based C18 packed column for HPLC, the prepared GC columns demonstrated a faster separation with a higher efficiency, comparable resolution and tailing factors, and lower consumption of carrier gas. Regarding the capillary columns prepared for HPLC, the chromatographic experiments exposed a much lower run time with a comparable efficiency and resolution and drastically lower consumption of mobile phase solvents and samples. The results demonstrate that the MMT-based polymethacrylate monolith composites are applicable as novel and promising separation media for analyzing various mixtures of interest in different fields, such as petrochemical and environmental samples.

The application of rapid test paper technology for pesticide detection in horticulture crops: a comprehensive review

Background

The ever increasing pests and diseases occurring during vegetable crop production is a challenge for agronomists and farmers. One of the practices to avoid or control the attack of the causal agents is the use of pesticides, including herbicides, insecticides nematicides, and molluscicides. However, the use of these products can result in the presence of harmful residues in horticultural crops, which cause several human diseases such as weakened immunity, splenomegaly, renal failure, hepatitis, respiratory diseases, and cancer. Therefore, it was necessary to find safe and effective techniques to detect these residues in horticultural crops and to monitor food security.

Main body

The review discusses the use of conventional methods to detect pesticide residues on horticultural crops, explain the sensitivity of nanoparticle markers to detect a variety of pesticides, discuss the different methods of rapid test paper technology and highlight recent research on rapid test paper detection of pesticides.

Conclusions

The methodologies discussed in the current review can be used in a certain situation, and the variety of methods enable detection of different types of pesticides in the environment. Notably, the highly sensitive immunoassay, which offers the advantages of being low cost, highly specific and sensitive, allows it to be integrated into many detection fields to accurately detect pesticides.

Recent advances in halal food authentication: Challenges and strategies

Increasing public awareness of food quality and safety has prompted a rapid increase in food authentication of halal food, which covers the production method, technical processing, identification of undeclared components, and species substitution in halal food products. This urges for extensive research into analytical methods to obtain accurate and reliable results for monitoring and controlling the authenticity of halal food. Nonetheless, authentication of halal food is often challenging because of the complex nature of food and the increasing number of food adulterants that cause detection difficulties. This review provides a comprehensive and impartial overview of recent studies on the analytical techniques used in the analysis of halal food authenticity (from 1980 to the present, but there has been no significant trend in the choice of techniques for authentication of halal food during this period). Additionally, this review highlights the classification of different methodologies based on validity measures that provide valuable information for future developments in advanced technology. In addition, methodological developments, and novel emerging techniques as well as their implementations have been explored in the evaluation of halal food authentication. This includes food categories that require halal authentication, illustrating the advantages and disadvantages as well as shortcomings during the use of all approaches in the halal food industry.

How Coffee Capsules Affect the Volatilome in Espresso Coffee

Coffee capsules have become one of the most used methods to have a coffee in the last few years. In this work, coffee was prepared using a professional espresso coffee machine. We investigated the volatilome of four different polypropylene coffee capsule typologies (Biologico, Dolce, Deciso, Guatemala) with and without capsules in order to reveal the possible differences in the VOCs spectra. The volatilome of each one was singularly studied through an analysis by gas chromatography and mass spectrometry (GC–MS), checking the abundance of different VOCs in coffee extracted with and without a capsule protection and compared to its related sample. Furthermore, ANOVA and Tukey tests were applied to statistically identify and individuate the possible differences. As a result, it was found that coffee capsules, offer advantages of protecting coffee from oxidation or rancidity and, consequently extended shelf life as well as did not cause a reduction of volatile compounds intensity. Therefore, it is possible to conclude that the aroma of polypropylene coffee capsule extraction is not damaged compared to a traditional espresso.

Full Workflows for the Analysis of Gas Chromatography-Ion Mobility Spectrometry in Foodomics: Application to the Analysis of Iberian Ham Aroma

Gas chromatography—ion mobility spectrometry (GC-IMS) allows the fast, reliable, and inexpensive chemical composition analysis of volatile mixtures. This sensing technology has been successfully employed in food science to determine food origin, freshness and preventing alimentary fraud. However, GC-IMS data is highly dimensional, complex, and suffers from strong non-linearities, baseline problems, misalignments, peak overlaps, long peak tails, etc., all of which must be corrected to properly extract the relevant features from samples. In this work, a pipeline for signal pre-processing, followed by four different approaches for feature extraction in GC-IMS data, is presented. More precisely, these approaches consist of extracting data features from: (1) the total area of the reactant ion peak chromatogram (RIC); (2) the full RIC response; (3) the unfolded sample matrix; and (4) the ion peak volumes. The resulting pipelines for data processing were applied to a dataset consisting of two different quality class Iberian ham samples, based on their feeding regime. The ability to infer chemical information from samples was tested by comparing the classification results obtained from partial least-squares discriminant analysis (PLS-DA) and the samples’ variable importance for projection (VIP) scores. The choice of a feature extraction strategy is a trade-off between the amount of chemical information that is preserved, and the computational effort required to generate the data models.

Data Science in the Food Industry

Food safety is one of the main challenges of the agri-food industry that is expected to be addressed in the current environment of tremendous technological progress, where consumers' lifestyles and preferences are in a constant state of flux. Food chain transparency and trust are drivers for food integrity control and for improvements in efficiency and economic growth. Similarly, the circular economy has great potential to reduce wastage and improve the efficiency of operations in multi-stakeholder ecosystems. Throughout the food chain cycle, all food commodities are exposed to multiple hazards, resulting in a high likelihood of contamination. Such biological or chemical hazards may be naturally present at any stage of food production, whether accidentally introduced or fraudulently imposed, risking consumers' health and their faith in the food industry. Nowadays, a massive amount of data is generated, not only from the next generation of food safety monitoring systems and along the entire food chain (primary production included) but also from the Internet of things, media, and other devices. These data should be used for the benefit of society, and the scientific field of data science should be a vital player in helping to make this possible.

US FDA-validated green GC-MS method for analysis of gabapentin, tramadol and/or amitriptyline mixtures in biological fluids

Background: Mixtures of gabapentin, tramadol and/or amitriptyline are usually recommended for treatment of neuropathic pain. Materials & methods/results: A novel GC-MS/MS method was developed to assess the studied mixture whether in pure forms or human biological fluids (plasma/urine). The chromatographic detection was performed using MS detector applying the selected ion-monitoring mode. An (Agilent, CA, USA) GC-MS with triple axis single quadrupole detector unit was used for the analysis equipped with HP-5MS (5% phenyl methyl siloxane) column. Helium was the carrier gas and positive electron impact ionization mode was applied. Conclusion: The developed method was able to assess the mixture components simultaneously within six minutes. Validation of the method was assured according to US FDA guidelines and Eco-Scale assessment.

Application of nanotechnology based-biosensors in analysis of wine compounds and control of wine quality and safety: A critical review

Nanotechnology is one of the most promising future technologies for the food industry. Some of its applications have already been introduced in analytical techniques and food packaging technologies. This review summarizes existing knowledge about the implementation of nanotechnology in wine laboratory procedures. The focus is mainly on recent advancements in the design and development of nanomaterial-based sensors for wine compounds analysis and assessing wine safety. Nanotechnological approaches could be useful in the wine production process, to simplify wine analysis methods, and to improve the quality and safety of the final product.

A Colorimetric pH Sensor Based on Clitoria sp and Brassica sp for Monitoring of Food Spoilage Using Chromametry

A developed colorimetric pH sensor film based on edible materials for real-time monitoring of food freshness is described. The mixed natural dyes from edible plants Clitoria sp and Brassica sp were extracted and incorporated into ι-carrageenan film as a colorimetric pH sensor film for monitoring food spoilage and its freshness. The color changes of the developed colorimetric sensor film were measured with chromametry and UV-vis spectroscopy, respectively. Experimental results show that colorimetric pH sensor film demonstrated statistically significant differences (p < 0.05) between CIE-L*a*b* coordinates color system indicated that the developed colorimetric sensor film was able to give a gradual change in color over a wide pH range. The color of the colorimetric sensor film also changes discretely and linearly with factors that contribute to food spoilage using shrimp and durian samples. Moreover, the developed colorimetric pH sensor film has the potential to be used as a safe, non-destructive testing and also a flexibly visual method for direct assessment of food freshness indicator during storage.

Metal-Organic Frameworks for Food Safety

Food safety is a prevalent concern around the world. As such, detection, removal, and control of risks and hazardous substances present from harvest to consumption will always be necessary. Metal-organic frameworks (MOFs), a class of functional materials, possess unique physical and chemical properties, demonstrating promise in food safety applications. In this review, the synthesis and porosity of MOFs are first introduced by some representative examples that pertain to the field of food safety. Following that, the application of MOFs and MOF-based materials in food safety monitoring, food processing, covering preservation, sanitation, and packaging is overviewed. Future perspectives, as well as potential opportunities and challenges faced by MOFs in this field will also be discussed. This review aims to promote the development and progress of MOF chemistry and application research in the field of food safety, potentially leading to novel solutions.

Comparative Study of Fatty Acids Profile in Eleven Wild Mushrooms of Boletacea and Russulaceae Families

Eleven species of wild mushrooms which belong to Boletaceae and Russulaceae families were examined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) analysis for the presence of fatty acids. As far as we know, the fatty acid profiles of B. purpureus and B. rhodoxanthus were described for the first time. Twenty-six fatty acids were determined. Linoleic (19.5 - 72%), oleic (0.11 - 64%), palmitic (5.9 - 22%) and stearic acids (0.81 - 57%) were present in the highest contents. In all samples, unsaturated fatty acids dominate. Agglomerative hierarchical clustering was used to display the correlation between the fatty acids and their relationships with the mushroom species. Based on the fatty acids profile in the samples, the mushrooms can be divided into two families: Boletaceae and Russulaceae families, using cluster analysis.

Comparison of two derivatization methods for the analysis of fatty acids and trans fatty acids in bakery products using gas chromatography

Two different procedures for the methylation of fatty acids (FAs) and trans fatty acids (TFAs) in food fats were compared using gas chromatography (GC-FID). The base-catalyzed followed by an acid-catalyzed method (KOCH3/HCl) and the base-catalyzed followed by (trimethylsilyl)diazomethane (TMS-DM) method were used to prepare FA methyl esters (FAMEs) from lipids extracted from food products. In general, both methods were suitable for the determination of cis/trans FAs. The correlation coefficients (r) between the methods were relatively small (ranging from 0.86 to 0.99) and had a high level of agreement for the most abundant FAs. The significant differences (P = 0.05) can be observed for unsaturated FAs (UFAs), specifically for TFAs. The results from the KOCH3/HCl method showed the lowest recovery values (%R) and higher variation (from 84% to 112%), especially for UFAs. The TMS-DM method had higher R values, less variation (from 90% to 106%), and more balance between variation and %RSD values in intraday and interday measurements (less than 4% and 6%, resp.) than the KOCH3/HCl method, except for C12:0, C14:0, and C18:0. Nevertheless, the KOCH3/HCl method required shorter time and was less expensive than the TMS-DM method which is more convenient for an accurate and thorough analysis of rich cis/trans UFA samples.

Microfluidic opportunities in the field of nutrition

Nutrition has always been closely related to human health, which is a constant motivational force driving research in a variety of disciplines. Over the years, the rapidly emerging field of microfluidics has been pushing forward the healthcare industry with the development of microfluidic-based, point-of-care (POC) diagnostic devices. Though a great deal of work has been done in developing microfluidic platforms for disease diagnoses, potential microfluidic applications in the field of nutrition remain largely unexplored. In this Focus article, we would like to investigate the potential chances for microfluidics in the field of nutrition. We will first highlight some of the recent advances in microfluidic blood analysis systems that have the capacity to detect biomarkers of nutrition. Then we will examine existing examples of microfluidic devices for the detection of specific biomarkers of nutrition or nutrient content in food. Finally, we will discuss the challenges in this field and provide some insight into the future of applied microfluidics in nutrition.

Rapid determination of main constituents of packed juices by reverse phase-high performance liquid chromatography: an insight in to commercial fruit drinks

The present work reports the compositional analysis of thirteen different packed fruit juices using high performance liquid chromatography (HPLC). Vitamin C, organic acids (citric and malic) and sugars (fructose, glucose and sucrose) were separated, analyzed and quantified using different reverse phase methods. A new rapid reverse phase HPLC method was developed for routine analysis of vitamin C in fruit juices. The precision results of the methods showed that the relative standard deviations of the repeatability and reproducibility were <0.05 and <0.1 respectively. Correlation coefficient of the calibration models developed was found to be higher than 0.99 in each case. It has been found that the content of Vitamin C was less variable amongst different varieties involved in the study. It is also observed that in comparison to fresh juices, the packed juices contain lesser amounts of vitamin C. Citric acid was found as the major organic acids present in packed juices while maximum portion of sugars was of sucrose. Comparison of the amount of vitamin C, organic acids and sugars in same fruit juice of different commercial brands is also reported.

Sample preparation methods in the analysis of pesticide residues in baby food with subsequent chromatographic determination

Pesticides are widely utilized at various stages of cultivation and during postharvest storage to protect plants against a range of pests and/or to provide quality preservation. Reliable confirmatory methods are required to monitor pesticide residues in baby foods and to ensure the safety of baby food supply. This review covers methods in which pesticide residues have been determined in baby food by the use of a wide range of chromatographic techniques after various sample preparation steps. The main attention is paid to the evaluation and improvement of sample extraction and clean-up methods (liquid extraction, solid-phase extraction (SPE), dispersive SPE (DSPE), microextraction procedures, matrix solid-phase dispersion (MSPD) and supercritical fluid extraction (SFE)) considering low concentration levels of pesticide residues in baby food resulting from stringent European Union (EU) legislation. Instrumental aspects together with the matrix effects significantly contributing to the most important parameters considered in pesticide residues analysis of baby food--limits of detection (LODs) and limits of quantification (LOQs) were included within the scope of this overview. Paper involves also monitoring studies.

Analytical aspects of plant metabolite profiling platforms: current standings and future aims

Over the past years, metabolic profiling has been established as a comprehensive systems biology tool. Mass spectrometry or NMR spectroscopy-based technology platforms combined with unsupervised or supervised multivariate statistical methodologies allow a deep insight into the complex metabolite patterns of plant-derived samples. Within this review, we provide a thorough introduction to the analytical hard- and software requirements of metabolic profiling platforms. Methodological limitations are addressed, and the metabolic profiling workflow is exemplified by summarizing recent applications ranging from model systems to more applied topics.