The Effect of Organic and Conventional Cultivation Systems on the Profile of Volatile Organic Compounds in Winter Wheat Grain, Including Susceptibility to Fusarium Head Blight.

The grain of 30 winter wheat cultivars differing in terms of their resistance to FHB (Fusarium head blight) was tested. The cultivars were grown in four variants of field trials established in a split-plot design: control without fungicides, chemical control of FHB with fungicides after Fusarium inoculation, Fusarium head inoculation, and organic cultivation. The profile of volatile compounds in grain samples was determined by mean headspace-solid phase microextraction and analyzed by gas chromatography time-of-flight mass spectroscopy. The identified volatile profile comprised 146 compounds belonging to 14 chemical groups. The lowest abundance of volatile organic compounds (VOCs) was found for the organic cultivation variant. The performed discriminant analysis facilitated the complete separation of grain for individual experimental variants based on the number of VOCs decreasing from 116 through 62, 37 down to 14. The grain from organic farming was characterized by a significantly different VOCs profile than the grain from the other variants of the experiment. The compounds 1-methylcycloheptanol, 2-heptanone, 2(3H)-furanone, and 5-hexyldihydro-2(3H)-furanone showed statistically significant differences between all four experimental variants.

Key Odorants of Lazur, a Polish Mold-Ripened Cheese.

Application of gas chromatography-olfactometry (GC-O) carried out on the volatile fraction isolated by solvent-assisted flavor evaporation (SAFE) and solid phase microextraction (SPME) from Lazur mold-ripened cheese revealed 17 odor-active compounds. The highest flavor dilution factor (FD) has been obtained for methanethiol (2048) with a burnt odor note and for 2(3)-methylbutanoic acid (2048) with a cheesy, pungent odor. Further quantitation of the 15 most aroma-active compounds allowed for calculation of their odor activity values (OAV). The highest OAVs were obtained for methanethiol (500), 3(2)-methylbutanoic acid (321), 3-(methylthio)propanal (210), 2,3-butanedione (65), dimethyl trisulfide (22), butanoic acid (20), 1-octen-3-ol (18), ( Z)-4-heptenal (14), dimethyl disulfide (14), dimethyl sulfide (13), phenylacetaldehyde (6), 2-ethyl-3,5-dimethylpyrazine (5), and acetic acid (4). An aroma recombination experiment showed slight differences in the perception of cheesy/sweaty and moldy/musty notes. To verify the influence of methyl ketones on the aroma profile of mold-ripened cheese, recombinant has been additionally supplemented with 2-pentanone, 2-heptanone, and 2-nonanone in concentrations determined in Lazur cheese. The aroma profile remained unchanged, which would suggest that methyl ketones, in this particular cheese, do not play a significant role in the formation of aroma.

Flavoromics approach in monitoring changes in volatile compounds of virgin rapeseed oil caused by seed roasting.

Two varieties of rapeseed (one high oleic - containing 76% of oleic acid, and the other - containing 62% of oleic acid) were used to produce virgin (pressed) oil. The rapeseeds were roasted at different temperature/time combinations (at 140-180°C, and for 5-15min); subsequently, oil was pressed from the roasted seeds. The roasting improved the flavour and contributed to a substantial increase in the amount of a potent antioxidant-canolol. The changes in volatile compounds related to roasting conditions were monitored using comprehensive gas chromatography-mass spectrometry (GC×GC-ToFMS), and the key odorants for the non-roasted and roasted seeds oils were determined by gas chromatography-olfactometry (GC-O). The most important compounds determining the flavour of oils obtained from the roasted seeds were dimethyl sulphide, dimethyltrisulfide, 2,3-diethyl-5-methylpyrazine, 2,3-butenedione, octanal, 3-isopropyl-2-methoxypyrazine and phenylacetaldehyde. For the oils obtained from the non-roasted seeds, the dominant compounds were dimethylsulfide, hexanal and octanal. Based on GC×GC-ToFMS and principal component analysis (PCA) of the data, several compounds were identified that were associated with roasting at the highest temperatures regardless of the rapeseed variety: these were, among others, methyl ketones (2-hexanone, 2-heptanone and 2-octanone).

Analysis of black pepper volatiles by solid phase microextraction-gas chromatography: A comparison of terpenes profiles with hydrodistillation.

Solid phase microextraction (SPME) is widely used in food flavor compounds analysis in majority for profiling volatile compounds. Based on such profiles conclusions are often drawn concerning the percentage composition of volatile compounds in particular food, spices or raw materials. This paper focuses on the usefulness of SPME for the profiling of volatile compounds from spices using black pepper as an example. SPME profiles obtained in different analytical conditions were compared to the profile of pepper volatiles obtained using hydrodistillation in Clevenger apparatus. The profiles of both monoterpenes and sesquiterpenes of black pepper were highly dependent on sample weight (0.1 and 1g samples were tested), and extraction time (durations from 2 to 120min were tested), regardless of the SPME fiber used (PDMS and CAR/PDMS coatings were used). The characteristic phenomenon for extraction from dry ground pepper was the decrease of monoterpenes % share in volatiles with increasing extraction times, whereas at the same time the % contents of sesquiterpenes increased. Addition of water to ground pepper substantially changed extraction kinetics and mutual proportions of mono to sesquiterpenes compared to dry samples by minimizing changes in mono- to sesquiterpenes ratio in different extraction times. Obtained results indicate that SPME can be a fast extraction method for volatiles of black pepper. Short extraction times (2-10min) in conjunction with the fast GC analysis (2.1min) proposed here may offer fast alternative to hydrodistillation allowing black pepper terpenes characterization.