Volatile organic compounds in beef and pork by gas chromatography‐mass spectrometry: A review

Volatile Compounds for Discrimination between Beef, Pork, and Their Admixture Using Solid-Phase-Microextraction-Gas Chromatography-Mass Spectrometry (SPME-GC-MS) and Chemometrics Analysis

This study addresses the prevalent issue of meat species authentication and adulteration through a chemometrics-based approach, crucial for upholding public health and ensuring a fair marketplace. Volatile compounds were extracted and analyzed using headspace-solid-phase-microextraction-gas chromatography-mass spectrometry. Adulterated meat samples were effectively identified through principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA). Through variable importance in projection scores and a Random Forest test, 11 key compounds, including nonanal, octanal, hexadecanal, benzaldehyde, 1-octanol, hexanoic acid, heptanoic acid, octanoic acid, and 2-acetylpyrrole for beef, and hexanal and 1-octen-3-ol for pork, were robustly identified as biomarkers. These compounds exhibited a discernible trend in adulterated samples based on adulteration ratios, evident in a heatmap. Notably, lipid degradation compounds strongly influenced meat discrimination. PCA and PLS-DA yielded significant sample separation, with the first two components capturing 80% and 72.1% of total variance, respectively. This technique could be a reliable method for detecting meat adulteration in cooked meat.

Characteristics of Purified Horse Oil by Supercritical Fluid Extraction with Different Deodorants Agents

This study investigated the impact of activated carbon, palm activated carbon, and zeolite on horse oil (HO) extracted from horse neck fat using supercritical fluid extraction with deodorant-untreated HO (CON) as a comparison. The yield and lipid oxidation of deodorant untreated HO (CON) were not significantly affected by the three deodorants. However, deodorant-treated HOs exhibited significantly elevated levels of α-linolenic acid (C18:3n3) and eicosenoic acid (C20:1n9) compared to CON (p<0.05), while other fatty acids remained consistent. Zeolite-purified HO demonstrated significantly lower levels of volatile organic compounds (VOCs) than other treatments (p<0.05). Remarkably, zeolite decreased the concentration of pentane, 2,3-dimethyl (gasoline odor), by over 90%, from 177.17 A.U. ×106 in CON to 15.91 A.U. ×106. Zeolite also effectively eliminates sec-butylamine (ammonia and fishy odor) as compared to other deodorant-treated HOs (p<0.05). Additionally, zeolite reduced VOCs associated with the fruity citrus flavor, such as nonanal, octanal, and D-limonene in HO (p<0.05). This study suggests that integrating zeolite in supercritical fluid extraction enhances HO purification by effectively eliminating undesirable VOCs, presenting a valuable approach for producing high-quality HO production in the cosmetic and functional food industries.

Volatile compounds produced in smoked bacon inoculated with potential spoilage bacteria

BACKGROUND

Volatile organic compounds (VOCs) produced during meat storage are mainly derived from the decomposition of meat components and the metabolism of spoilage bacteria. VOCs produced in sterile bacon model substrate inoculated or un-inoculated with spoilage bacteria, Staphylococcus xylosus (P2), Leuconostoc mesenteroides (P6), Carnobacterium maltaromaticum (P9), Leuconostoc gelidum (P16) and Serratia liquefaciens (P20), previously isolated, were identified by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Furthermore, combinations of the strains (Pm) were also obtained.

RESULTS

In total, 54 volatile compounds, including aldehydes, alcohols, phenols, ketones, alkanes, alkanes, organic acids, esters and so forth, were determined after 45 days of storage in bacon inoculated with potential spoilage bacteria using the HS-SPME/GC-MS method. VOC concentrations of alcohols and organic acids in groups inoculated with bacteria were remarkably higher (P < 0.05) compared to that in control samples. Specifically, some VOCs are closely related to the metabolic activity of the inoculated bacterial strains; for example, 2,3-butanediol was associated with P2, P16 and P20, and acetic acid was mainly related to P6 and P9.

CONCLUSION

The results of partial least squares regression indicated that there was a high correlation between the electronic nose sensors and VOCs of smoked inoculated potential spoilage bacteria. These compounds are potentially important for predicting deterioration of smoked bacon. © 2023 Society of Chemical Industry.

Rapid headspace solid-phase microextraction sheets with direct analysis in real time mass spectrometry (SPMESH-DART-MS) of derivatized volatile phenols in grape juices and wines

Volatile phenols possess "smoky, spicy" aromas and are routinely measured in grapes, wines and other foodstuffs for quality control. Routine analyses of volatile phenols rely on gas chromatography - mass spectrometry (GC-MS), but slow throughput of GC-MS can cause challenges during times of surge demand, i.e. following 'smoke taint' events involving forest fires near vineyards. Parallel extraction of headspace volatiles onto sorbent sheets (HS-SPMESH) followed by direct analysis in real time mass spectrometry (DART-MS) is a rapid alternative to conventional GC-MS approaches. However, HS-SPMESH extraction is poorly suited for lower volatility odorants, including volatile phenols. This work reports development and validation of an HS-SPMESH-DART-MS approach for five volatile phenols (4-ethylphenol, 4-ethylguiacol, guaiacol, 4-methylguaiacol, and cresols). Prior to HS-SPMESH extraction, volatile phenols were acetylated to facilitate their extraction. A unique feature of this work was the use of d₆-Ac₂O as a derivatizing agent to overcome issues with isobaric interferences inherent to chromatography-free MS techniques. The use of alkaline conditions during derivatization resulted in cumulative measurement of both free and bound forms of volatile phenols. The validated HS-SPMESH-DART-MS method achieved a throughput of 24 samples in ∼60 min (including derivatization and extraction time) with low limits of detection (<1 μg L^-1) and good repeatability (3-6% RSD) in grape and wine matrices. Validation experiments with smoke-tainted grape samples indicated good correlation between total (free + bound) volatile phenols measured by HS-SPMESH-DART-MS and a gold standard GC-MS method.

Comparison of physiochemical attributes, microbial community, and flavor profile of beef aged at different temperatures

Beef aging for tenderness and flavor development may be accelerated by elevated temperature. However, little to no research has been undertaken that determines how this affects other important meat quality characteristics and microbial community. This study aims to decrease aging time by increasing temperature. Beef were aged and vacuum packaged at 10 and 15°C, and the effects of increased temperature on meat physiochemical attributes, microbial community, and flavor profile were monitored. The shear force decreased with aging in all temperature and showed the higher rate at elevated temperatures compare to 4°C. The beef aged at elevated temperatures (10 or 15°C) for 5 days showed equivalent shear force value to the beef aged at 4°C for 10 days (p  >  0.05), however, the final tenderness was not affected by the elevated temperature. The beef aged at elevated temperatures showed a significantly higher cooking loss and less color stability compared to 4°C (p  <  0.05). The total volatile basic nitrogen and aerobic plate count increased (p  <  0.05) faster at elevated temperatures compare to 4°C. Carnobacterium, Lactobacillus and Hafnia-Obesumbacterium were the dominant genus in the beef samples aged at 4, 10, and 15°C, respectively. In addition, the contents of isobutyraldehyde, 3-methylbutyraldehyde, 2-methylbutyraldehyde, and 3-methylbutanol were higher than aged at 4°C (p  <  0.05). Therefore, these results suggest that application of elevated aged temperatures could shorten required aging time prior while not adversely affecting meat quality. In turn, this will result in additional cost savings for meat processors.

Formation and Analysis of Volatile and Odor Compounds in Meat-A Review

The volatile composition and odor of meat and meat products is based on the precursors present in the raw meat. These are influenced by various pre-slaughter factors (species, breed, sex, age, feed, muscle type). Furthermore, post-mortem conditions (chiller aging, cooking conditions, curing, fermentation, etc.) determine the development of meat volatile organic compounds (VOCs). In this review, the main reactions leading to the development of meat VOCs such as the Maillard reaction; Strecker degradation; lipid oxidation; and thiamine, carbohydrate, and nucleotide degradation are described. The important pre-slaughter factors and post-mortem conditions influencing meat VOCs are discussed. Finally, the pros, cons, and future perspectives of the most commonly used sample preparation techniques (solid-phase microextraction, stir bar sorptive extraction, dynamic headspace extraction) and analytical methods (gas chromatography mass spectrometry and olfactometry, as well as electronic noses) for the analysis of meat VOCs are discussed, and the continued importance of sensorial analysis is pinpointed.