Headspace solid-phase microextraction and on-fiber derivatization for the determination of 3-/2-MCPDE and GE in breast milk and infant formula by gas chromatography tandem mass spectrometry

Determination of chloropropanol esters and glycidyl esters in instant noodles based on solid-phase microextraction with chitosan-β-cyclodextrin coated fiber

We developed a method for the determination of chloropropanol esters and glycidyl esters (GE) in instant noodles using solid-phase microextraction with chitosan-β-cyclodextrin (CS-β-CD) coated fiber coupled with gas chromatography-tandem mass spectrometry. The developed low-cost fiber coating can improve the sensitivity of the method. Immobilized enzymes can improve operational stability and reusability compared to free enzymes, thereby reducing costs. The adsorption isotherm was modeled using the Langmuir model, while the adsorption kinetics followed the pseudo second-order model. The limit of detection was 0.3 ng/L. The method exhibited satisfactory recoveries for the analytes, ranging from 80.2 % to 105.3 %, with relative standard deviations < 9.9 %. Furthermore, the results of the exposure assessment showed that chloropropanol esters do not pose unacceptable risks to different age groups. However, the margin of exposure for GE suggested a potential health risk for populations between the ages of 3 and 12 years old.

A comprehensive evaluation of milk protein molecular weight distribution based on exclusion chromatography dataset

Molecular weight is one of the main characteristic parameters of proteins, which is the basis for the functional properties of milk protein. This research aims at establishing molecular weight distribution pattern of milk protein based on exclusion chromatography. The method selected Na3PO4-Na2SO4 (0.1 M, pH 6.7) buffer as the mobile phase and detected at 220 nm by HPLC-UV. The protein molecular weight distributions were determined and compared for human milk, bovine milk, and infant formula. The proportion of macromolecular proteins is much higher in infant formula compared to human or bovine milk. The protein molecular weights of human and bovine milk are significantly different around 90, 20, 14, and 2 kDa. The results provide holistic compare of bovine milk, human milk, and infant formula through protein molecular distribution. The new evaluation indicators for protein will drive technological simulation of infant formula.

Changes of the volatile compounds and odors in one-stage and three-stage infant formulas during their secondary shelf-life

The odor of infant formula changes due to alterations in its volatile composition during the shelf life. However, there is currently a lack of research on whether the odor changes in infant formula during the secondary shelf life, which refers to the period of repeated opening and usage in daily life. This study used headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-electrostatic orbitrap high-resolution mass spectrometry (GC-Orbitrap-MS) to investigate the volatile composition changes in one-stage and three-stage infant formulas during different stages (0 day, 3 days, and 7 days during the secondary shelf-life, i.e. simulated daily use). A total of 32 volatiles were identified, including nine aldehydes, seven ketones, four alcohols, three furans, two sulfur compounds, two esters, and five terpenoids. Of these, 16 compounds changed significantly in one-stage samples and 23 compounds in three-stage samples within 7 days of the secondary shelf-life. Further the odor of the three-stage infant formula samples was found changed substantially after 3 days of simulated use by using the triangle test. This study highlighted the considerable alterations in volatile compound composition and sensory changes during the simulated daily use and provided valuable insights for consumers in selecting and using infant formula products, as well as a new perspective for enterprises to improve the sensory quality of their products.

Lipidomics Analysis Explores the Mechanism of Renal Injury in Rat Induced by 3-MCPD

3-monochloropropane-1,2-diol (3-MCPD) is a food-process toxic substance, and its main target organ is the kidney. The present study examined and characterized the nephrotoxicity and the lipidomic mechanisms in a model of kidney injury in Sprague Dawley (SD) rats treated with high (45 mg/kg) and low (30 mg/kg) doses of 3-MCPD. The results showed that the ingestion of 3-MCPD led to a dose-dependent increase in serum creatinine and urea nitrogen levels and histological renal impairment. The oxidative stress indicators (MDA, GSH, T-AOC) in the rat kidney altered in a dose-dependent manner in 3-MCPD groups. The lipidomics analysis revealed that 3-MCPD caused kidney injury by interfering with glycerophospholipid metabolism and sphingolipid metabolism. In addition, 38 lipids were screened as potential biomarkers. This study not only revealed the mechanism of 3-MCPD renal toxicity from the perspective of lipidomics but also provided a new approach to the study of 3-MCPD nephrotoxicity.

Risk assessment of 3-MCPD esters and glycidyl esters from the formulas for infants and young children up to 36 months of age

Esters of 2-monochloropropane-1,2-diol (2-MCPD), 3- monochloropropane-1,2-diol (3-MCPD), and glycidol are present in infant formulas, follow-on foods and similar compositions. They arise mainly from the vegetable oil content and may cause harmful effects in consumers. The contents of these substances in formulas were determined indirectly by converting the esters to the free form, followed by derivatization and analysis by gas chromatography-tandem mass spectrometry (GC-MS/MS). The validation results demonstrate that the method had sufficient specificity and adequate accuracy. The limits of detection (LOD) and limits of quantification (LOQ) for each of 2-MCPDE, 3-MCPDE, and GE were 1.5 and 5 µg/kg, respectively. Formula intake by children up to 36 months of age was surveyed, and the data was used to assess the risks due to 3-MCPD esters (3-MCPDE) and glycidyl esters (GE). The mean exposure dose of 3-MCPDE for different age groups ranged from 0.51 to 1.13 µg/kg bw per day. The corresponding mean GE exposure ranged from 0.031 to 0.069 µg/kg bw per day. Neither mean values nor the percentile 95% values of 3-MCPDE exposure doses exceed the recommended provisional maximum tolerable daily intake (PMTDI).

Rapid discrimination of the identity of infant formula by triple-channel models

Infant formula is related to children's life and health. However, the existing identification methods for infant formula are time-consuming, costly and prone to environmental pollution. Therefore, a simple, efficient and less polluting identification method for infant formula is urgently needed. The aim of this study was to distinguish between goat and cow infant formula using HS-SPME-GC-MS and E-nose combined with triple-channel models. The results indicated that the main difference of them attributed to thirteen volatile compounds and three sensor variables. Based on this, the linear discriminant and partial least squares discriminant analyses were conducted, and a multilayer perceptron neural network model was constructed to identify the commercial samples. There was a high percentage of correct classifications (>90%) in samples. Together, our work demonstrated that the volatile compounds of infant formula combined with chemometric analysis were effective and rapid for detecting two infant formulas.

Automated method using direct-immersion solid-phase microextraction and on-fiber derivatization coupled with comprehensive two-dimensional gas chromatography high-resolution mass spectrometry for profiling naphthenic acids in produced water

Naphthenic acids (NAs) are naturally occurring organic acids in petroleum and are found in waste waters generated during oil production (produced water, PW). Profiling this class of compounds is important due to flow assurance during oil exploration. Compositional analysis of PW is also relevant for waste treatment to reduce negative impacts on the environment. Here, comprehensive two-dimensional gas chromatography coupled with high-resolution mass spectrometry (GC×GC-HRMS) was applied as an ideal platform for qualitative analysis of NAs by combining the high peak capacity of the composite system with automated scripts for group-type identification based on accurate mass measurements and fragmentation patterns. To achieve high-throughput profiling of NAs in PW samples, direct-immersion solid phase microextraction (DI-SPME) was selected for extraction, derivatization and preconcentration. A fully automated DI-SPME method was developed to combine extraction, fiber rinsing and drying, and on-fiber derivatization with N-methyl-N‑tert-butyldimethylsilyltrifluoroacetamide (MTBSTFA). Data processing was based on filtering scripts using the Computer Language for Identifying Chemicals (CLIC). The method successfully identified up to 94 NAs comprising carbon numbers between 6 and 18 and hydrogen deficiency values ranging from 0 to -4. The proposed method demonstrated wider extraction coverage compared to traditional liquid-liquid extraction (LLE) - a critical factor for petroleomic investigations. The method developed also enabled quantitative analysis, exhibiting detection limits of 0.5 ng L^-1 and relative standard deviation (RSD) at a concentration of NAs of 30 µg L^-1 ranging from 4.5 to 25.0%.

Bibliometric Analysis of Research Trends on 3-Monochloropropane-1,2-Diol Esters in Foods

3-Monochloropropane-1,2-diol esters (3-MCPDE) are common food contaminants mainly formed in the edible oil refining process. Due to their potential hazards, 3-MCPDE has become a widespread food safety concern. In this study, CiteSpace and VOSviewer were used to conduct a bibliometric analysis on the 3-MCPDE research papers collected in the Web of Science Core Collection from 1998 to 2022. The results showed that the number of research publications on 3-MCPDE has increased rapidly since 2010. Analysis of the hotspots in 3-MCPDE studies showed that more attention has been paid to the exposure assessment, formation mechanism, detection methods, mitigation methods and toxicity, and toxicology of 3-MCPDE. Finally, the future trends of research on 3-MCPDE were analyzed and proposed. The mitigation methods and toxicology studies of 3-MCPDE are still the research hotspots in the future. In addition, nutritional intervention for 3-MCPDE toxicity will be an emerging trend.

Occurrence, formation mechanism, detection methods, and removal approaches for chloropropanols and their esters in food: An updated systematic review

Chloropropanols, one of the major contaminants in food, and the corresponding esters or glycidyl esters (GEs) are of great concern in terms of product safety due to their potential carcinogenicity. During heat processing, glycerol, allyl alcohol, chloropropanol esters, sucralose, and carbohydrate in mixed foodstuffs are probable precursors of chloropropanol. The standard analytical techniques for chloropropanols or their esters are GC-MS or LC-MS following sample derivatization pretreatment. By comparing modern data against that five-year-old before, it appears that the levels of chloropropanols and their esters/GEs in food products have somewhat decreased. 3-MCPD esters or GEs may yet exceed the permitted intake set, however, especially in newborn formula which requires particularly stringent regulatory measures. Citespace (6.1. R2) software was employed in this study to examine the research focii of chloropropanols and their corresponding esters/GEs in the literature.

Migration study of phenolic endocrine disruptors from pacifiers to saliva simulant by solid phase microextraction with amino-functionalized microporous organic network coated fiber

Parabens, bisphenols, and triclosan are used in many baby products, including pacifiers. However, the migration through oral saliva will result in a potential health risk. The present study proposes a sensitive and simple method for the analysis of these chemicals in saliva simulants by solid phase microextraction (SPME) with amino-functionalized microporous organic network (MON-NH₂) coated fiber. The MON-NH₂ showed an excellent adsorption ability for phenolic compounds. The adsorption isotherm fitted the Langmuir isotherm model and the adsorption kinetics followed the pseudo second-order model. The developed SPME method exhibited wide linear ranges (0.005-500 µg/L), good linearity, low limits of quantitation (0.005 µg/L), great recoveries (87.0-112.5 %), and excellent precision (RSD < 8.3 % for intra-day and RSD < 13.7 % for inter-day). Mathematical models based on Fick's second law were applied to predict migration from pacifiers into saliva simulants and a good fit between theoretical and experimental migration results was found. The daily exposure assessment results indicated that these chemicals in pacifiers do not pose unacceptable health risks to infants. However, exposure risks still should be monitored and appropriate precautions are still needed to protect infants from exposure to these chemicals.

Methods, principles, challenges, and perspectives of determining chloropropanols and their esters

Chloropropanols and their esters are a group of food contaminants that have various toxicities to the human body. Research and control to chloropropanols and their esters is important to food safety. Therefore, the sensitive, accurate, precise, and effective determination of chloropropanols and their esters is highly essential to study their concentration, formation, and mitigation. The indirect method, commonly applied in the determination of chloropropanols and their esters, is based on the cleavage of ester bond, extraction, and derivatization. The conventional indirect method will still be the mostly used method in the near future due to its good sensitivity and feasibility, although its parameters need to be chosen and optimized according to sample stuffs and chloropropanol concentrations. Meanwhile, direct method and other quantitative methods should also be developed for special applications, such as studying the profile of chloropropanol esters and rapid screening protocol. The challenges and future perspectives of these methods are discussed in this review. This review can provide a reference on the selection, designation, and modification of methods for determining chloropropanols and their esters.