Headspace Solid-phase Microextraction-gas Chromatography-mass Spectrometry Research Articles

Discrimination and characterization of the volatile organic compounds in eight kinds of huajiao with geographical indication of China using electronic nose, HS-GC-IMS and HS-SPME-GC–MS

Huajiao (Zanthoxylum bungeanum maxim. and Zanthoxylum armatum DC.) is a highly prized spice in China due to its distinctive aroma and taste. The volatile organic compounds (VOCs) of eight kinds of red and green huajiao which varied according to geographical indication of P.R. China were evaluated by electronic nose (E-nose), headspace solid-phase microextraction–gas chromatography-mass spectrometry (HS-SPME-GC–MS) and headspace-gas chromatography–ion mobility spectrometry (HS-GC-IMS). Results showed that red huajiao emitted more terpenes, esters, and fewer alcohols than green huajiao. Partial least squares-discriminant analysis based on GC–MS and GC-IMS data was revealed a good classifying tool for huajiao from different original habitats. Four and eight aroma substances were selected as the potential markers by the variable importance in projection (VIP) variable selection method, respectively. The results of the current study provide a useful basis in the huajiao aroma difference study. Additionally, a rapid huajiao aroma analysis method using GC-IMS was developed.

Effects of ultra-long fermentation time on the microbial community and flavor components of light-flavor Xiaoqu Baijiu based on fermentation tanks.

Microbial structure and succession of fermented grains play a significant role in Baijiu’s flavor and quality. In this study, high-throughput sequencing (HTS) coupled with headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) were used to analyze the microbial community structures and flavor components in the fermented grains at the end of fermentation from different fermentation time of light-flavor Xiaoqu Baijiu. HTS results showed that Lactobacillus acetotolerans, Lactobacillus helveticus, Lactobacillus buchneri, Wickerhamomyces, Saccharomyces, and Condenascus were identified as the dominant microbes, but Lactobacillus (96.28%) exhibited obvious advantages at the end of ultra-long fermentation time (day 98). HS-SPME-GC-MS analysis revealed that esters and alcohols had the most abundance in fermented grains of day 98, containing high concentrations of ethyl acetate, diethyl succinate, phenylethyl alcohol, isoamyl alcohol, and n-propanol, which were related to the succession of Lactobacillus and yeast communities. Interestingly, the content of n-propanol in the ultra-long fermentation time samples (day 98) was 6 times of that in normal fermented grains (day 14), which may be caused by higher abundance of Lactobacillus in day 98 samples. Monte Carlo permutation test showed residual starch, acidity, and amino nitrogen (p < 0.05) were important factors affecting the microbial community. Together, these results shed light on the physicochemical changes, microbial dynamics, and key flavor components of fermented grains at the end of fermentation from different fermentation time and provide a strategy for further improvement of Baijiu quality.

Extraction and Identification of a Wide Range of Microplastic Polymers in Soil and Compost.

Microplastic pollution is globally widespread; however, the presence of microplastics in soil systems is poorly understood, due to the complexity of soils and a lack of standardised extraction methods. Two commonly used extraction methods were optimised and compared for the extraction of low-density (polyethylene (PE)) and high-density microplastics (polyethylene (PET)), olive-oil-based extraction, and density separation with zinc chloride (ZnCl2). Comparable recoveries in a low-organic-matter matrix (soil; most >98%) were observed, but in a high-organic-matter matrix (compost), density separation yielded higher recoveries (98 ± 4% vs. 80 ± 11%). Density separation was further tested for the extraction of five microplastic polymers spiked at different concentrations. Recoveries were >93% for both soil and compost, with no differences between matrices and individual polymers. Reduction in levels of organic matter in compost was tested before and after extraction, as well as combined. Double oxidation (Fenton’s reagent and 1 M NaOH) exhibited the highest reduction in organic matter. Extracted microplastic polymers were further identified via headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS). This method has shown the potential for descriptive quantification of microplastic polymers. A linear relationship between the number of particles and the signal response was demonstrated for PET, polystyrene (PS), polyvinyl chloride (PVC), and PE (R2 > 0.98 in alluvial soil, and R2 > 0.80 in compost). The extraction and identification methods were demonstrated on an environmental sample of municipal biowaste compost, with the recovery of 36 ± 9 microplastic particles per 10 g of compost, and the detection of PS and PP.

Chemical Diversity between Three Graminoid Plants Found in Western Kenya Analyzed by Headspace Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS)

In recent work, it was shown that the graminoid plants Cynodon dactylon (Poaceae), Cyperus exaltatus (Cyperaceae), and Panicum repens (Poaceae) have an ovipositional effect on the malaria vector Anopheles gambiae in olfactometric bioassays. In order to get a view of the diversity of semiochemicals present in the environment of the vector during olfactometric trials, in the present work, the volatile profiles of these graminoid plants were analyzed using headspace solid-phase microextraction (HS-SPME) together with gas chromatography–mass spectrometry (GC-MS). In addition, one-way ANOVA comparison of compounds detected in two or more headspace samples are presented in order to provide a basis for comparison of compounds that could constitute a starting point for novel blends of volatile organic compounds to be tested as oviposition attractants.

Exploitation of virgin olive oil by-products (Olea europaea L.): phenolic and volatile compounds transformations phenomena in fresh two-phase olive pomace ('alperujo') under different storage conditions.

BACKGROUNDMuch effort has recently been spent for re‐using virgin olive oil by‐products as nutraceutical ingredients for human diet thanks to their richness in bioactive phenols, but their management is not easy for producers. We aimed to provide useful information for a better management of fresh olive pomace before drying, by studying the phenolic and volatile compounds transformations phenomena of fresh olive pomace stored under different conditions planned to simulate controlled and uncontrolled temperature conditions in olive oil mills.RESULTSThe evolution of the phenolic and volatile compounds was studied by high‐performance liquid chromatography‐diode array detector mass spectrometry (HPLC‐DAD‐MS) and headspace solid‐phase microextraction gas chromatography‐mass spectrometry (HS‐SPME‐GC‐MS). The phenolic profile varied rapidly during storage: the verbascoside content decreased about 70% after 17 days even at 4 °C, while the content of simple phenols such as hydroxytyrosol and caffeic acid increased over time. The low temperature was able to slow down these phenomena. A total of 94 volatile organic compounds (VOCs) were detected in the fresh olive pomace, with a prevalence of lipoxygenase (LOX) VOCs (78%), mainly aldehydes (19 490.9 μg kg−1) despite the higher number of alcohols. A decrease in LOX volatiles and a quick development of the ones linked to off‐flavors (carboxylic acids, alcohols, acetates) were observed, in particular after 4 days of storage at room temperature. Only storage at 4 °C allowed these phenomena to be slowed down.CONCLUSIONTo preserve the natural phenolic phytocomplex of fresh olive pomace before drying and to avoid off‐flavors development, storage in open containers must be avoided and a short storage in cold rooms (7–10 days) is to be preferred. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Comparison of the Fruit Volatile Profiles of Five Muscadine Grape Cultivars (Vitis rotundifolia Michx.) Using HS-SPME-GC/MS Combined With Multivariate Statistical Analysis.

Fruit aromas are composed of a complex mixture of volatile organic compounds, which are essential attributes associated with the overall flavor and consumer preference. Muscadine grape (MG; Vitis rotundifolia Michx.) is an aroma-dense fruit crop. However, there is very scarce information on its volatile profiles. In this study, the volatile constituents of five newly introduced MG cultivars, including Alachua, Carlos, Fry, Granny Val, and Noble, were profiled using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS) combined with multivariate statistical analysis. A total of 44 compounds, including esters, aldehydes, alcohols, fatty acids, terpenes, ketones, and furan, were identified and relatively quantified. Principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) evidently discriminated against the five MG cultivars based on their volatile profiles. The specific volatiles that contributed the most to this discrimination were highlighted. Geraniol and cinnamyl alcohol were demonstrated to be essential for characterizing the Alachua MG cultivar, whereas ethyl trans-2-butenoate and propyl acetate were shown to be important compounds to characterize the Noble MG cultivar. The results further showed that 2-Ethyl-1-hexanol, (Z)-3-hexenal, and (E)-2-hexenol were closely related to Carlos, Fry, and Granny Val cultivars, respectively. This investigation is the first in-depth exploration of the volatile profiles of the aroma-dense muscadine grape, which is essential for future genetic or biotechnological improvements to attain a cultivar with the desired flavor.

Varietal Aromas of Fortified Wines from Different Moscato Var. (Vitis vinifera L.) under the Same Pedoclimatic Conditions.

Vitis vinifera L. cv. Moscato includes different varieties mainly used to produce sweet wines, such as fortified wines. Moscato grapes are characterized by a large number of free and glycosylated monoterpenoids giving very aromatic wines. However, the literature data on the aroma profile of fortified Moscato wines are very limited. In light of this, the present research aimed to investigate the aroma compounds, mainly the varietal ones, of fortified wines from different Moscato varieties, namely Giallo (Yellow), Bianco (White), Bianco at Petit Grain (Blanc à Petits Grains), Ottonel and Rosa (Pink of Trentino), cultivated under the same pedoclimatic conditions. Using the HS-SPME-GC-MS (head space-solid phase micro extraction-gas chromatography-mass spectrometry) technique, numerous varietal and fermentative aroma compounds have been identified and quantified and significant differences were observed among varieties in the levels of mostly volatiles and in their ratios. Based on their composition, the studied wines can be divided in two groups depending on whether linalool or geraniol prevails among varietal aromas. These results are evidence that each Moscato variety has a typical varietal aroma composition, even if some similarities were found between the two white varieties, and between Moscato Giallo and Moscato Ottonel varieties. Moscato Rosa showed a peculiar aroma composition and the lowest ester/terpene ratio.

Identification of characteristic volatiles and metabolomic pathway during pork storage using HS-SPME-GC/MS coupled with multivariate analysis

Previous researches have been conducted evaluating the volatile compounds of pork. However, data regarding the changes in volatiles and metabolic pathways during pork storage were inadequately investigated. Herein, a headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS) coupled multivariate analysis was proposed for characterizing the profiles of volatile compounds and metabolic pathways during pork storage. A total of 37 metabolites, including aldehydes, ketones, alcohols etc. were successfully identified. Multivariate statistical analysis revealed a substantial variation in metabolite phenotype among samples over the pork storage period, with 12 characteristic metabolites and 5 potential characteristic metabolites screened as biomarkers. Moreover, three metabolomic pathways analysis and transformation between each other (thermal reactions, lipid metabolism and amino acid metabolism) reveals the underlying mechanisms of metabolites change of pork. Therefore, the present study may provide insight into future understanding of the variation in the pork metabolite profiles.

Analysis of aroma and polyphenolic compounds in Saperavi red wine vinified in Qvevri.

The purpose of this study is to analyze and characterize a Georgian red wine from Saperavi grape, obtained in Qvevri (Georgian traditional winemaking method), by using innovative techniques for the determination of the polyphenolic content, aroma, and its correlation to the sensory characteristics. This peculiar red wine, after high‐performance liquid chromatography with diode‐array detection and mass spectrometry (HPLC‐DAD‐MS), headspace solid‐phase microextraction–gas chromatography–mass spectrometry (HS‐SPME‐GC‐MS), and HS‐SPME‐GCxGC‐MS/TOF (two‐dimensional gas chromatography) chemical characterization showed a high polyphenol content (19.6 × 102 mg/L, 38.4% anthocyanins) and a wide range of volatile compounds, among which terpenes were associated with the aroma of flowers, lemongrass, and wood. Analyses were also conducted to determine the total polyphenol content correlated to antioxidant activity with the Folin–Ciocalteu spectrophotometric in vitro method (4.650 g GAE/L). In conclusion, for the first time on Saperavi wine, innovative techniques such as HPLC‐DAD‐MS, GC‐MS, and GCxGC‐MS/TOF were simultaneously applied in association with the traditional analytic techniques to perform a complete chemical characterization. These activities are part of a project about circular viticulture in the Georgian territory that will lead the production of traced quality wines and the valorization of the Georgian wine sector.

Dynamic changes of 3-MCPD esters and glycidyl esters contents as well as oil quality during repeated deep-frying

In this study, the dynamic changes of 3-monochloropropane-1,2-diol esters (3-MCPDEs) and glycidyl esters (GEs) in both oils and French fries were assessed using headspace–solid phase microextraction–gas chromatography–mass spectrometry over the course of 5 days repeated deep-frying. The color parameter, as well as the concentrations of tocopherols and total polar components (TPC) in frying oils, were also evaluated. The content of 3-MCPDEs in frying oil reduced by 71.2% in the first two days of frying while GEs increased steadily. The concentration of 3-MCPDEs in French fries increased over the repeated frying while GEs and oil uptake maintained constant. The concentration of tocopherols decreased while TPC increased significantly during repeated deep-frying. Microstructure analysis of French fries by X-ray micro-computed tomography (micro-CT) indicated the reduction of micropores and the appearance of bigger oil-filled macropores, which might be responsible for the enrichment effect of French fries on 3-MCPDEs and GEs. This research broadens the understanding of the fate of 3-MCPDEs and GEs in repeated deep-frying.

Comparison of different edible parts of bighead carp (Aristichthys nobilis) flavor.

The study aims to obtain the information on taste and odor among different edible parts (white dorsal meat, white abdomen meat, white tail meat, and dark meat) of bighead carp. The results showed that the white dorsal meat and white abdomen meat had the higher content of total amino acids among all edible parts of bighead carp samples. The highest inosine monophosphate and adenosine monophosphate content presented in white abdomen meat, and the highest equivalent umami concentration value presented in dark meat. The principal component analysis result of electronic tongue and electronic nose showed significant differences in the overall taste and odor characteristics among four group samples. Additionally, 41, 30, 42, and 29 volatile compounds were identified by headspace solid-phase microextraction/gas chromatography-mass spectrometry among white dorsal meat, white abdomen meat, white tail meat, and dark meat of bighead carp, respectively. Based on the data of relative olfactory activity value (ROAV ≥ 1), 12 relative olfactory activity compounds may mainly contribute to the overall odor of bighead carp, including 2-methylbutanal, hexanal, heptanal, (E)-2-octenal, nonanal, dodecanal, undecanal, decanal, 3-methyl-1-pentanol, 1-octen-3-ol, (Z)-2-octen-1-ol, and eucalyptol. Furthermore, according to the Partial Least Squares Discriminant Analysis profile derived from the ROAV of 12 characteristic volatile compounds, significant variations in the odor of different edible parts of bighead carp. Overall, there was a significant difference in taste and odor among different edible parts of bighead carp, and this study may provide useful information for unraveling the flavor characteristics of each edible part of raw bighead carp. PRACTICAL APPLICATIONS: The comprehensive information on taste and odor among different edible parts (white dorsal meat, white abdomen meat, white tail meat, and dark meat) of bighead carp were obtained using liquid chromatography-mass spectrometry, automatic amino acid analyzer, electronic tongue (E-tongue), headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS), and electronic nose (E-tongue), respectively. This study may provide useful information for unraveling the flavor characteristics of each edible part of raw bighead carp and improving the flavor of bighead carp products.

An investigation using a validated method based on HS-SPME-GC-MS detection for the determination of 2-dodecylcyclobutanone and 2-tetradecylcyclobutanone in X-ray irradiated dairy products

The headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) technique was used to investigate 2-dodecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB) as X-ray induced markers in irradiated dairy products. For the first time, an intensive study on several types of milk and cheeses, was carried out to evaluate both the suitability of this analytical technique for dairy products and how different factors related to these types of food, such as matrix composition, ripening time and technological processes, can affect 2-DCB and 2-TCB extraction. The results demonstrated that these analytes were identified in all types of irradiated samples, even if 2-TCB showed a lower sensibility than 2-DCB. Moreover, for both analytes, increasing irradiation dose over the experimental range of 0.5–5.0 kGy, a linear response was observed in all the matrices studied. The minimum dose level (MDL) and limit of detection (LOD), in irradiated and spiked samples, were 0.5 kGy and 5.0 μg L−1, respectively. Furthermore, linear correlation between 2-DCB and 2-TCB contents was demonstrated. Finally, chemometric analysis highlighted the influence of ripening time and dairy technological processes on extraction capability of the two investigated analytes.

Production of aromatic three-line hybrid rice using novel alleles of BADH2.

Aroma is a key grain quality trait that directly influences the market price of rice globally. Loss of function of betaine aldehyde dehydrogenase 2 (OsBADH2) affects the biosynthesis of 2‐acetyl‐1‐pyrroline (2‐AP), which is responsible for aroma in fragrant rice. The current study was aimed at creating new alleles of BADH2 using CRISPR/Cas9 gene editing technology under the genetic background of the japonica Ningjing 1 (NJ1) and indica Huang Huazhan (HHZ) varieties. Sensory evaluation and analysis using headspace solid‐phase microextraction gas chromatography–mass spectrometry (HS‐SPME‐GC‐MS) showed that the grains of the four homozygous T1 lines with new alleles of BADH2 (nj1‐cr BADH2‐1, nj1‐cr BADH2‐2, hhz‐cr BADH2‐1 and hhz‐cr BADH2‐2) produced moderate fragrance and had significantly increased 2‐AP content compared with wild‐types. Moreover, there were no significant differences in the amylose content and gelatinization temperature among the four lines with new alleles of BADH2 to the wild‐types. Thereafter, we crossed the HHZ background new alleles of BADH2 with CMS line Taonong 1A (TN1A) to produce a three‐line hybrid variety B‐Tao‐You‐Xiangzhan (BTYXZ) with increased grain aroma. The 2‐AP content in grains of the improved BTYXZ‐1 and BTYXZ‐2 reached at 26.16 and 18.74 μg/kg, and the gel consistency of BTYXZ‐1 and BTYXZ‐2 increased significantly by 9.1% and 6.5%, respectively, compared with the wild‐type Tao‐You‐Xiangzhan (TYXZ). However, the γ‐aminobutyric acid (GABA) content in the improved three‐line hybrid rice BTYXZ‐1 (5.6 mg/100 g) and BTYXZ‐2 (10.7 mg/100 g) was significantly lower than that of the TYXZ. These results demonstrated that CRISPR/Cas9 gene editing technology could be successfully utilized in improving aroma in non‐fragrant japonica and indica varieties. In addition, the newly developed BADH2 alleles provided important genetic resources for grain aroma improvement in three‐line hybrid rice.

Chemical and Antimicrobial Analyses of Juniperus chinensis and Juniperus seravschanica Essential Oils and Comparison with Their Methanolic Crude Extracts

Juniperus chinensis and Juniperus seravschanica are commonly used in the traditional folk medicine to treat microbial infection. In this study, the essential oils obtained from the leaves of J. chinensis growing in Malaysia and J. seravschanica growing in Oman were analysed by head space-solid phase microextraction-gas chromatography mass spectrometry (HS-SPME-GC-MS) and screened for antimicrobial activities against Escherichia coli (NCTC 10418), Pseudomonas aeruginosa (NCTC 10662), Bacillus subtilis ATCC6059, Micrococcus luteus (ATCC 9341), Staphylococcus aureus (NCTC 6571), and methicillin-resistant S. aureus (MRSA; ATCC 33591). To compare the antimicrobial activities of extracts using different extraction methods, methanol extraction was performed to obtain crude extracts from the leaves of J. chinensis and J. seravschanica for antimicrobial analysis. The HS-SPME-GS-MS analysis of the essential oils from the leaves of J. chinensis and J. seravschanica identified 37 and 36 components, respectively. Essential oils from these two species had distinctive chemical component profiles, with α-pinene (27.2%) as the major component of J. chinensis essential oil, while dl-limonene (45.2%) constitutes the major component of J. seravschanica essential oil. Essential oils of these two species shared only six similar terpenoids compounds: α-pinene, β-pinene, γ-elemene, sabinene, elemol, and 3-cyclohexen-1-ol. Overall, the essential oils showed antimicrobial activities against all the six bacterial strains tested, with the highest antagonistic activity against M. luteus and B. cereus; while, methanolic crude extracts showed the highest activities against S. aureus and MRSA strains. The methanolic crude extracts demonstrated significantly higher antibacterial activity against the Gram-positive bacteria (p < 0.005); while, the essential oils of Juniperus did not show significant differences between Gram-positive and Gram-negative bacteria. Future studies are needed to investigate the active compounds present in the essential oils and methanolic crude extracts that confer the selectivity in the antimicrobial activity.

Electronic Nose Differentiation between Quercus robur Acorns Infected by Pathogenic Oomycetes Phytophthora plurivora and Pythium intermedium.

Identification of the presence of pathogenic oomycetes in infected plant material proved possible using an electronic nose, giving hope for a tool to assist nurseries and quarantine services. Previously, species of Phytophthora plurivora and Pythium intermedium have been successfully distinguished in germinated acorns of English oak Quercus robur L. Chemical compound analyses performed by HS-SPME/GC-MS (Headspace Solid-Phase Microextraction/Gas Chromatography–Mass Spectrometry) revealed the presence of volatile antifungal molecules produced by oak seedlings belonging to terpenes and alkanes. Compounds characteristic only of Phytophthora plurivora or Pythium intermedium were also found. Methylcarveol occurred when germinated acorns were infected with Pythium, while neophytadiene (isomer 2 and 3) occurred only when infected with Phytophthora. Moreover, isopentanol was found in acorns infected with Phytophthora, while in control, isopentyl vinyl ether was not observed anywhere else. Among the numerous volatile compounds, isopentanol only occurred in acorns infected with Phytophthora and methylcarveol in acorns infected with Pythium.

Influence of Selenium Biofortification on the Growth and Bioactive Metabolites of Ganoderma lucidum.

Selenium biofortification of edible and medicinal mushrooms is an effective way to produce selenium-enriched food supplements. Ganoderma lucidum is the typical one with excellent biological activity. This study investigated G. lucidum growth and bioactive metabolites alterations during liquid culture with different concentrations of selenite. Low selenium levels did not affect growth and mycelia morphology, whereas high selenium levels negatively influenced growth, dramatically decreased biomass, caused nucleic acid and protein leakage, damaged cell walls and membranes, and resulted in indicators such as degraded cells, a red color, and an unpleasant odor. Through headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis, ten volatile Se compounds were identified in G. lucidum with 200 ppm selenite, which led to an odor change, whereas only three with 50 ppm selenite. SeMet was the major selenoamino acid in the 50 ppm selenite group by high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS), but more MeSeCys was produced with 200 ppm selenite. Polysaccharide yields were promoted and inhibited with 50 and 200 ppm selenite, respectively. These results provide comprehensive insights into the effects of selenite on G. lucidum in liquid culture and are beneficial for functional selenium-enriched mushroom production and improving nutritive values.

Biosynthetic Mechanism of Key Volatile Biomarkers of Harvested Lentinula edodes Triggered by Spore Release.

In this study, headspace solid-phase microextraction-gas chromatography-mass spectrometry, multivariate analyses, and transcriptomics were used to explore the biosynthesis of key volatiles and the formation of spores in Lentinula (L.) edodes. Among the 50 volatiles identified, 1-octen-3-ol, phenethyl alcohol, and several esters were considered key aromas because of their higher odor activity values. Eleven volatiles were screened as biomarkers by orthogonal partial least squares discriminant analysis, and hierarchical cluster analysis showed that these biomarkers could represent all volatiles to distinguish the spore release stage. The activities of lipoxygenase (LOX), hydroperoxide lyase, alcohol dehydrogenase, and alcohol acyltransferase were higher in L. edodes with spore release. Moreover, linolenic acid and phenylalanine metabolism were involved in aroma biosynthesis. One LOX-related gene and five aryl alcohol dehydrogenase-related genes could regulate the biosynthesis of 1-octen-3-ol, phenethyl alcohol, and phenylacetaldehyde. In addition, several key genes were involved in meiosis to regulate sporulation.

Effect of Adding Essential Oils of Caraway and Rosemary on Volatile Aroma Compounds Derived from Stored Vacuum Packaged Minced Turkey Meat

Abstract Changes in the odor of meat during its storage are one of the basic indicators affecting its assessment and possible disqualification. The aim of the study was to determine whether the addition of essential oils may affect the composition and concentration of volatile compounds included in the aroma of stored turkey meat. We investigated the effect of adding essential oil (EO) of caraway (0.02% v/w), rosemary (0.02% v/w) and a mixture of the two (0.01% each) on the composition of volatile compound fractions formed during 10-day storage of vacuum-packed minced turkey meat. The EOs used were also evaluated for their influence on microbial contamination (total viable count and lactic acid bacteria count), sensory quality (odor and taste) and the level of fat rancidity (acid value, peroxide value and p-anisidine value) and pH in chill-stored samples. In terms of sensory indicators, the greatest beneficial effect of adding EOs was noted in the odor of raw meat. Use of the HS-SPME/GC-MS (headspace-solid phase microextraction/gas chromatography-mass spectrometry) method showed that the addition of essential oils significantly reduced the amounts of benzeneacetaldehyde, 2-octenal and ethyl 2-methyloctanoate compared with the control sample. In addition, in the presence of essential oils of rosemary and caraway, decreases were noted in benzaldehyde and 9-octadecenal, respectively. These changes may potentially affect the reception of the odor. There was a beneficial effect of the EOs in reducing the levels of fat oxidation indicators, including peroxides. However, the oils at applied concentrations had no significant effect on the total viable count and LAB count.

Microwave pretreatment of camellia (Camellia oleifera Abel.) seeds: Effect on oil flavor

Microwave is a new pretreatment technology, and microwave processing time of camellia seeds is a factor affecting the flavor of camellia seed oil (CSO). Therefore, this study on the characteristic volatile compounds of CSO from microwaved seeds with different processing time was carried out by electronic nose (E-nose), headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). The results of E-nose show that W1W, W2W and W5S were the main sensors to distinguish the flavor profile of CSOs. Through HS-SPME-GC-MS and odor activity value analysis, 80 volatile compounds were detected and 22 key aroma compounds were screened in CSOs. Compared with HS-SPME-GC-MS, 44 volatile compounds were detected by HS-GC-IMS, including 9 identical compounds and 35 different compounds. In general, the volatile compounds of 0, 2 and 3 min CSOs were mainly alcohols and esters, while the 4, 5 and 6 min CSOs were mainly heterocycles and aldehydes.

Varietal authentication of virgin olive oil: Proving the efficiency of sesquiterpene fingerprinting for Mediterranean Arbequina oils

Virgin olive oil (VOO) is a highly appreciated product fundamental in the Mediterranean diet. Since its sensory attributes are greatly influenced by the olive cultivar, the varietal authentication of VOOs is needed to protect consumers from misleading information. The present study aims to evaluate the suitability of sesquiterpene hydrocarbon (SH) fingerprint as VOO cultivar marker beyond geographical, agronomical and processing conditions. The study was mainly focused on Mediterranean Arbequina oils. SH profile of more than 400 VOOs from 6 counties and 38 different cultivars and coupages was analysed by Headspace Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS). Partial Least Square-Discriminant Analysis (PLS-DA) classification models were built with the aligned chromatograms. A binary PLS-DA model was built to distinguish ‘Arbequina’ oils from those of other cultivars (non-‘Arbequina’ class) and it was externally validated. The results of the external validation showed a 95.1% of overall correct classification confirming the suitability of SH fingerprint as a screening method for the authentication of Arbequina VOO. Also, the discrimination capacity of SH fingerprinting to authenticate VOOs from other cultivars was preliminary explored and promising results were obtained.