Determination of potential volatiles markers from citrus, eucalyptus, cotton, and wild flower Palestinian honeys using SPME followed by GCMS analysis

The volatiles of Palestinian honeys from citrus of the orange blossom (citrus spp.), eucalyptus (eucalyptus camaldulensis), cotton (Gossypium hirsutum L.) and wildflower (poyfloral) were investigated. They were separated, identified and quantitatively analyzed by using Headspace Solid-Phase Microextraction and Gas Chromatography Mass Spectrometry (HS-SPME-GCMS) technology to estimate the amount of volatiles evolved. Although the investigated honeys have some volatiles in common but still each of them possess specific characteristic volatiles. For example, citrus honey was characterized by the presence of three volatile compounds namely, 2-methoxy-4 (1-propanol) phenol, 1-hydroxylinalool, and 2-amino benzoic acid methylester. These compounds are absent from all other honeys. Eucalyptus honey was found to have 2-propyl-1-pentanol and pentadecane as potential markers. Cotton honey was characterized by the presence of three markers, 2-furanomethanol, eicosane and 2-methyl decanol. The wildflower honey is distinguished from other floral honey by the presence of three volatile marker compounds the hexadecane, heptadecane and 3,4-dimethyl benzaldehyde

Determination of unifloral honey volatiles from Centaurea iberica and Zizyphus spina-christi by Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry

The volatiles of two different unifloral Palestinian honeys from botanical species Centaurea iberica and Zizyphus spina-christi have been investigated for the first time. They were isolated, identified, and quantitatively analyzed using Headspace Solid-Phase Microextraction and Gas Chromatography Mass Spectrometry (HS-SPME-GCMS) methodology. The resulted total ion current (TIC) chromatographic profiles reflected the uniqueness of each type of honey and therefore the proposed procedure can be used to characterize each kind of honey by revealing the absence or presence of certain volatile constituents. A total of 18 compounds were seen in Centaurea iberica honey with phenylacetaldehyde, phenylethylalcohol, 2-ethyl hexanoic acid, 2,4,6-trimethylphenol and nonanoic acid as the principal components, whereas 25 compounds were seen in Zizyphus spinachristi honey with benzaldehyde, phenylacetaldehyde, phenylethylalcohol, benzeneacetonitrile, 2-ethyl hexanoic acid, octanoic acid, 2-methoxy-4-(1-propanol)-6-acetate phenol, nonanoic acid, decanoic acid, 1-hydroxy 2,4,6-trimethylbenzene, and 5-hydroxymethyl- 2-furaldehyde as the principal constituents. Ziziphus spina-christi honey was found to have two unequivocal potential markers: phenylacetonitrile and 5-hydroxymethyl-2-furancarboxaldehyde, while Centaurea Italica honey has only one representative floral origin marker compound: the 2,4,6-trimethylphenol

Primary investigation into the occurrence of Hydroxymethylfurfural (HMF) in a range of smoked products

5-hydroxymethylfurfural (HMF) is produced in foods through many different pathways. Recently, studies have revealed its potential mutagenic and carcinogenic properties. Determination of HMF was originally used as an indicator of both the extent of thermal processing a food had undergone and food quality. It has been identified in a variety of food products such as bread, breakfast cereals, fruit juices, milk and honey. In addition to the thermal processes that lead to the formation of HMF during thermal treatment, food smoking also creates conditions that result in the formation of HMF. This can take place within the food due to the elevated temperatures associated with hot smoking, or by the proximity of the products of the pyrolysis of the wood matrix that is used for smoking (cold smoking). This may lead to further contamination of the product by HMF over and above that associated with the rest of the preparation process. Until now, there have been no studies examining the relation between the smoking procedure and HMF contamination in smoked food. This study is a primary investigation measuring HMF levels in three categories of smoked food products; cheese, processed meat, and fish using HPLC-UV. The amount of HMF found in all three product categories supports our hypothesis that HMF levels are due to both internal pathways during processing and external contamination from smoke generation matrix (wood) employed. The results ranged from 1 ppb (Metsovone traditional Greek smoked cheese) to 4ppm (Hot-smoked ready to eat mackerel). Subsequently for smoked cheese products, a correlation was found between HMF and phenolic compounds generated by the smoking procedures and identified by SPME-GCMS. It was observed that cheese samples that had higher concentrations of HMF were also found to have higher concentrations of syringol and cresols. It is important therefore to understand the smoking procedure’s effect on HMF formation. This will aid in the development of mitigation strategies to reduce HMF formation while retaining the flavour of the smoked products

Efficacy of Trichoderma against Sclerotium rolfsii causing collar rot disease of lentil under in vitro conditions

Three biocontrol agents viz., Trichoderma viride, T. virens and T. harzianum were evaluated to test the antagonism against Sclerotium rolfsii under in vitro conditions. All the three antagonists’ viz., T. viride, T. virens and T. harzianum have shown the potential of parasitizing the growth of Sclerotium rolfsii in vitro. The rate of inhibition was fastest in T. harzianum (63.60%) followed by T virens (51.5 %). Least inhibition was recorded in T. viride (50.85% ) after 72 hours of incubation. However, T. viride showed the highest (91.31%) reduction in sclerotia formation followed by T. harzianum (84.92%) and T. virens (84.29%) after 15 days of incubation. The volatile compounds from Trichoderma viride were found most effective in suppressing the mycelial growth (51.11%) and sclerotia production (95.90%) of the target pathogen. The culture filtrate from both T. harzianum and T. viride (15% concentration) was found very effective in inhibiting the radial growth (57.46 and 49.62%) and sclerotia formation (98.20 and 99.83%) of Sclerotium rolfsii. The antagonists such as T. harzianum and T. viride can be used as a bio-control agent against S. rolfsii under field condition

The physiochemical responses of stored grain insect pests to synthetic amorphous silica (SAS) powders

Fumigation is widely used for the disinfestation of stored grain products. Every loss of grain during storage is a loss of all the inputs that produced the grain in the first place. In many situations, fumigation is the only feasible process for pest control. Currently, phosphine is the only fumigant accepted by international trade for the disinfestation of grain and oilseeds. However, phosphine resistance now occurs worldwide and has challenged the continued use of phosphine in the grain industry. Food-grade synthetic amorphous silica (SAS) can act as a phosphine resistance breaker in storage systems. This thesis explored the mechanisms of SAS powder for controlling two phosphine-resistant stored grain insects, red flour beetle (Tenebrionidae: Tribolium castaneum (Herbst, 1797)) and lesser grain borer (Bostrichidae: Rhyzopertha dominica (Fabricius, 1792)). Grain protection during storage is essential. Both contact grain protectants and fumigants leave toxic residue issues to humans and the environment. The world wants residue-free grain, especially countries where grain is a substantial proportion of the diet. A high sensitivity headspace-solid phase micro-extraction gas chromatograph-mass spectrometer (HS-SPME-GCMS) method was optimised and validated to determine the residues of eight fumigants simultaneously, including phosphine, methyl bromide, cyanogen, sulfuryl fluoride, ethylene oxide, propylene oxide, ethyl bromide and ethyl formate. A 2 cm long 50/30μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) coated SPME fiber was chosen based on its absorption performance. The food matrices included grain, oilseed, dried fruit, and nuts. The limits of detection (LODs) of the fumigants ranged between 0.03 to 1.99 ng/g. Responses to a range of diluted authentic standards gave significant (r2 > 0.9983) linear regressions and the relative standard deviations (RSDs) were ≤ 8.7% at the 3 ng/g level of aged spiking standard, except for sulfuryl fluoride with a LOD of 1.99 ng/g and an RSD value of 39.7% (6.64 ng/g). The performance of the HS-SPME-GCMS method was more sensitive than the gas syringe method for all fumigants, except sulfuryl fluoride. Due to residue issues, the world is increasingly demanding residue-free treatments. The main components of insects' cuticular lipids are hydrocarbon compounds. SAS powders may change the hydrocarbons on the cuticle, impacting an insect’s self-protection mechanism(s) against toxic gas chemicals, possibly by acting as a barrier between the insect and the surrounding phosphine environment. X-ray micro-computed tomography (Micro-CT) scanning of SAS treated and untreated T. castaneum indicated that the SAS powder penetrates the tracheal system of T. castaneum and potentially blocks it, leading to asphyxiation. Micro-CT 3D reconstruction model of R. dominica showed the internal body fluid was completely depleted and the internal organs shrank. Based on metabolomics, several energy metabolites and derivatives were found to alter after applying food-grade SAS powders to adult T. castaneum and R. dominica. Phosphine-resistant adults are known to downregulate or slow the consumption of energy substances to survive phosphine fumigation. Fortunately, the food-grade SAS powders accelerated the carbohydrate metabolism leading to the depletion of monosaccharides, and the blocking of the β-oxidation pathway causing the accumulation of free fatty acids (FFAs). The excess FFAs, including saturated and unsaturated FFAs, possibly induce the lethal toxicity of the fatty acids. The associated bioassay results show that hydrophilic (HL) SAS and hydrophobic (HB) SAS controlled the larvae and adults of T. castaneum and R. dominica; however, HB-SAS was more efficient than HL-SAS when the moisture content and relative humidity were high. HB-SAS stimulated T. castaneum to increase respiration and produce benzoquinones and derivatives, leading to its death within two hours of treatment. The respiration rate of the insects was monitored by Mass Spectrometry (MS), and varied with HL-SAS and hydrophobic HB-SAS treatments. Volatile organic chemicals were identified and quantitated from adult T. castaneum by headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GCMS). Three benzoquinone derivatives, ethyl p-Benzoquinone, methyl p-Benzoquinone, and ethyl 1, 3-Benzenediol, were increased significantly by 133.1, 43.1 and 41.9 folds, respectively. Importantly, these benzoquinone derivatives can be used as biomarkers to identify phosphine-resistant strains of T. castaneum two hours after SAS treatment by HS-SPME-GCMS. The smaller particle size allowed the two SAS dusts to pass through open spiracles during air exchange. Due to their light weight, SAS particles are carried along with airflow into the tracheole tubes, which lie within the haemolymph and internal tissues. Small amounts of biofluid in the tracheole tubes evaporated due to the SAS treatments leading to the overwhelming loss of oxygen and water near the muscle cells. Therefore, the irritation of the SAS powder particles provides high insecticidal efficacy, even against phosphine-resistant individuals. In conclusion, food-grade SAS powders kill phosphine-resistant insect adults, T. castaneum and R. dominica, by depleting sugar energy and inhibiting the β-oxidation of FFAs to energy substances. Consequently, SAS powders offer a viable, pesticide residue free alternative to phosphine for managing and eradicating stored product insects

A chromatographic approach to distinguish Gram-positive from Gram-negative bacteria using exogenous volatile organic compound metabolites

This paper utilized L-alanine aminopeptidase activity as a useful approach to distinguish between Gram-negative and Gram-positive bacteria. This was done using two enzyme substrates, specifically 2-amino-N-phenylpropanamide and 2-amino-N-(4-methylphenyl)propanamide which liberated the volatile compounds aniline and p-toluidine, respectively. Two complementary analytical techniques have been used to identify and quantify the VOCs, specifically static headspace multicapillary column gas chromatography ion mobility spectrometry (SHS-MCC-GC-IMS) and headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS). Superior limits of detection were obtained using HS-SPME-GC-MS, typically by a factor of x6 such that the LOD for aniline was 0.02 μg/mL and 0.01 μg/mL for p-toluidine. In addition, it was also possible to determine indole interference-free by HS-SPME-GC-MS at an LOD of 0.01 μg/mL. The approach was applied to a range of selected bacteria: 15 Gram-negative and 7 Gram-positive bacteria. Use of pattern recognition, in the form of Principal Component Analysis, confirmed that it is possible to differentiate between Gram-positive and Gram-negative bacteria using the enzyme generated VOCs, aniline and p-toluidine. The exception was Stenotrophomonas maltophilia which showed negligible VOC concentrations for both aniline and p-toluidine, irrespective of the analytical techniques used and hence was not characteristic of the other Gram-negative bacteria investigated. The developed methodology has the potential to be applied for clinical and food applications

A comparative aroma and volatile profile investigation of 2016 and 2017 vintage Bull’s Blood wine samples

A kísérlet célja az egri Bikavérek aromaprofil felvétele, valamint érzékszervi összevetése volt, ehhez 2016-os és 2017-es Classicus Bikavér mintákat gyűjtöttünk. A vizsgálatok érzékszervi bírálatot, GC-MS készülékkel végzett aromaprofil vizsgálatot, valamint WineScan készülékkel az alapparaméterek vizsgálatát foglalta magában. Az érzékszervi vizsgálatoknál szempont volt a bor megjelenése (szín és tisztaság), az illat (intenzitás, fajta karakter, minőség), zamat (intenzitás, fajta karakter, minőség, hosszúság), valamint az összbenyomás a borról. Az aromaprofil vizsgálatokhoz HS-SPME-GCMS technikát használtunk. Az aromák minőségi kiértékelése után statisztikailag értékeltük az eredményeket, amely során négy aroma és egy alap paraméter, valamint az érzékszervi vizsgálatok szempontjai között összefüggést találtunk. Egy aromavegyület pozitív, a többi negatív irányba befolyásolta az érzékszervi bírálatokon adott pontszámokat, míg az alap paraméter pozitív irányba tolta el a borok megítélését. A kutatási eredményeket későbbiekben fel lehet használni egy adatbázis létrehozására, valamint vizsgálni a vásárlói attitűdöt. ----- In our research, our aim was to examine the volatile compounds of Bull’s Blood originated from Eger, and search correlation between them and organoleptic analysis. To reach these goals, we collected 2016 vintage and 2017 vintage Bull’s Blood samples from different wineries. The research includes organoleptic analysis, volatile compound profile examined with GC-MS, and studying basic parameters, using WineScan. . Organoleptic analysis’ points were givens for the look of the wine (colour and clarity), Fragrance (intensity, character and quality), Flavour (intensity, character and quality) and General impression. For examining volatile compounds, we used HS-SPME-GCMS technique, as it is suitable to study aromas. After qualitation of volatile compounds, we used a statistic programme, and there was correlation between four aroma, one basic parameter and some of organoleptic analysis’ part. One aroma had positive effect, three aromas has negative effects, and the basic parameter had positive effect on organoleptic analysis

Effects of Pretreatment and Drying on the Volatile Compounds of Sliced Solar-Dried Ginger (Zingiber officinale Roscoe) Rhizome

Ginger (Zingiber officinale Roscoe) rhizomes are mostly used as spice and medicine due to their high aroma intensity and medicinal bioactive compounds. However, the volatile compounds of ginger, partly responsible for its aroma and medicinal properties, can be affected by the pretreatment, drying method, and extraction processes employed. The objective of this study was to assess the effects of pretreatment and drying on the volatile compounds of yellow ginger variety at nine months of maturation. The effect of potassium metabisulfite (KMBS) and blanching pretreatment and drying on the volatile compounds of ginger using head space solid-phase microextraction with GCMS/MS identification (HS-SPME/GCMS/MS) was investigated. KMBS of concentrations 0.0 (control), 0.1, 0.15, 0.2, and 1.0% and blanching at 50°C and 100°C were used for pretreatment and dried in a tent-like concrete solar (CSD) dryer and open-sun drying (OSD). The different concentrations of KMBS-treated fresh ginger rhizomes did not result in any particular pattern for volatile compound composition identification. However, the top five compounds were mostly sesquiterpenes. The 0.15% KMBS-treated CSD emerged as the best pretreatment for retaining α-zingiberene, β-cubebene, α-farnesene, and geranial. The presence of β-cedrene, β-carene, and dihydro-α-curcumene makes this study unique. The 0.15% KMBS pretreatment and CSD drying can be adopted as an affordable alternative to preserve ginger