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.
Cold‐pressed rapeseed oil is among the most popular virgin oils. Different processing methods yield oils varying in chemical composition and oxidative stability. The experiment aimed at identifying the differences (mostly in volatiles) between rapeseed oil obtained from peeled seeds (RO) and oils obtained by three pre‐treatment methods: pressing whole seeds (WSO), flakes (FO) and roasted flakes (RFO). Volatiles were analysed using GCxGC‐ToFMS and data were processed using statistical multivariate analysis. Fatty acid composition was determined using GC‐FID. The oils’ oxidative stability was measured using peroxide value. Free fatty acids’ value, absorbance at 236 and 238 nm and chlorophyll content were also determined. Also, a sensory panel evaluation was performed. PCA was found to be effective tool for differentiating the oils on the basis of their volatile compounds. RO was most similar to WSO from the second pressing. Fatty acid composition analysis yielded differences between the experimental oils and RO. RO had the highest PV, p‐AV and Totox values. WSO from the first pressing (WSO1) had the highest oxidative stability. Sensory analysis found that WSO1 was most similar to RO. Both oils had an intense cabbage‐like and fruity odour. The study showed that the results of volatile compounds’ analysis differs from those of sensory analysis in oils comparison.
Practical applications: The results demonstrate that the rapeseed oil obtained from whole seeds may have a volatile compounds composition that is similar to that of rapeseed oil obtained from peeled seeds. PCA makes it possible to differentiate between samples varying in pre‐treatment method as well as between samples subjected to the same pre‐treatment method, but obtained from a second pressing. Sensory panel performed by trained panellists may demonstrate which oils are most desirable when rated for selected attributes. The results of sensory panel may differ from those of volatile compound analysis performed with GCxGC‐ToFMS.
In the current study, the volatile compounds in cold‐pressed rapeseeds oil obtained from peeled seeds with those in rapeseed oils obtained from seeds prepared with various pre‐treatment methods are compared. The obtained results are compared with those of sensory evaluation. The study shows that the results obtained by means of statistical analysis based on volatile compounds do not always correlate with those of sensory panel evaluation in oils comparison.
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