Anna Sadowska-Rociek

Comparison of different modifications on QuEChERS sample preparation method for PAHs determination in black, green, red and white tea

The aim of this work was the evaluation of QuEChERS extraction method for polycyclic aromatic hydrocarbon (PAH) determination in various types of tea. In the experiment, different kinds of extraction solvents, sorbents and a final method of sample preparation were compared. The final extracts were analysed by gas chromatography-selected ion monitoring-mass spectrometry. The results suggest that acetonitrile extraction, clean up with SAX and final liquid–liquid extraction was the best combination giving the most purified extracts and acceptable compound recoveries for different types of teas. In the study of real samples, compounds belonging to light PAHs were mostly detected, and heavy polycyclic aromatic hydrocarbons, including benzo[a]pyrene, were not identified in any of samples.

Development of a sample preparation method for acrylamide determination in cocoa via silylation

This paper reports the development of a rapid and simple sample preparation method for acrylamide (AA) determination in cocoa powder through conversion to N,O-bis(trimethylsilyl)acrylamide. The AA level was quantified in relation to an acrylamide-d3 internal standard using gas chromatography coupled with ion-trap mass spectrometry in the single ion monitoring mode (GC-SIM-MS). The analytical procedure consisted of extraction with an organic solvent (acetonitrile with/without hexane addition), extract purification by dispersive solid-phase extraction (d-SPE) using various sorbents (SAX, C18, ENV, Florisil) apart from the PSA sorbent, followed by derivatisation with N,O-bis (trimethylsilyl) trifluoroacetamide (BSTFA) and finally chromatographic analysis (GC-SIM-MS) using a deuterated internal standard. Nine variants of the method were tested. The usefulness of the method has been verified based on the recovery ratio of acrylamide. The obtained results showed that the best recovery of 98.2% with RSD lower than 10% was obtained using a combination of sorbents PSA and C18 with the addition of hexane in the initial stage of the extraction. The developed method has been successfully applied to the determination of acrylamide in 9 cocoa powder and 30 chocolate (dark, milk and white) samples purchased at a Polish supermarket. The results of AA content ranged from 54.2 to 168.0 μg kg−1 and from 25.5 to 256.1 μg kg−1 in cocoa powder and chocolate, respectively. The obtained results were in good agreement with literature reports.

The effects of adding “flavour enhancers” on levels of chloropropanediol esters and glycidyl esters in savoury shortbread

The effect of the addition of selected flavour enhancers (dried garlic, dried onion, caraway seeds, poppy seeds, kelp, sesame, Herbs de Provence) on levels of chloropropanediol esters (2-MCPDE, 3-MCPDE) and glycidyl esters (GE) was investigated in classic savoury shortbread with standard and reduced salt level. The changes in the amount of esters after a 2-month storage period were also analysed. Finally, selected products with reduced salt level were evaluated by consumers. The obtained results suggested that the MCPDE and GE present in bakery fat were transferred to the dough and partially decomposed during baking. Ester degradation depended on the presence of flavour additives and the amount of salt. The addition of poppy seeds or sesame accelerated the degradation, whereas onion and garlic inhibited the decomposition and, in some cases, promoted the endogenous formation of 3-MCPDE. The added salt also partially inhibited the decomposition of 3-MCPD esters but had no impact on 2-MCPDE changes. After a 2-month storage period, the level of 3-MCPDE increased in all samples that did not contain salt, while in salty products as well as for 2-MCPDE no such trends were observed. GE levels decreased after 2 months in almost all investigated samples. The consumer acceptability tests showed that the addition of poppy seeds or sesame seeds to the shortbread with reduced salt was highly evaluated by consumers. Hence, the addition of these flavour enhancers can mask the reduced salt amount, thereby lowering not only the level of sodium in the diet, but also the levels of toxic contaminants such as MCPDE or GE.