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Headspace-solid Phase Microextraction (headspace-solid + phase_microextraction)
Selected AbstractsAnalysis of key aroma components in cider from Shaanxi (China) Fuji appleINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2009Bangzhu Peng Summary Aroma components play an important role in the quality of cider. To understand the contribution of every component to cider aroma quality, major aroma components present in ten ciders processed with different technological methods with different yeasts and apple orchards were determined by Headspace-solid phase microextraction,gas chromatography,mass spectrometry and internal standard method. Experimental results by principal component analysis indicated that ethyl acetate, acetic acid isobutylester, isopentylacohol acetate, ethyl caprylate, ethyl 4-hydroxybutanoate, isopentylalcohol, 3,4,5-trimethyl-4-heptanol, nonyl alcohol, 3-methylthio-1-propanol serve as the key aroma components in cider from Shaanxi (China) fuji apple. A model was established and verified for evaluating aroma quality based on factor analysis by comparing with the sensory evaluation method. [source] Volatile compounds characterising Tunisian virgin olive oils: the influence of cultivarINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2010Dhouha Krichene Summary In this work, the volatile profiles of four Tunisian virgin olive oils were established by headspace-solid phase microextraction and gas chromatography, using flame ionisation and mass spectrometer detectors. More than eighty compounds were isolated and characterised, representing 97,99% of the total GC area. The main volatile compounds present in the oil samples were determined quantitatively, the major constituents were often aldehydes, particularly (E)-2-hexenal (48,90%). Significant differences in the content of volatile constituents were observed. These quantitative differences were used to distinguish between virgin olive oils from different varieties. [source] Changes of Headspace Volatiles in Milk with Riboflavin PhotosensitizationJOURNAL OF FOOD SCIENCE, Issue 7 2009J.H. Lee ABSTRACT:, Effects of fluorescent light, riboflavin, ascorbic acid, sodium azide, and butylated hydroxyanisole (BHA) on the volatiles in milk at 4 °C were determined using a combination of headspace-solid phase microextraction (HS-SPME), gas chromatography (GC), and mass spectrometry (MS). Pentanal, hexanal, heptanal, and dimethyl disulfide were formed only in the milk stored under light and increased significantly as the duration of light exposure increased from 0 to 8 h and the concentration of added riboflavin increased from 5 to 50 ppm (P,< 0.05). As fat content in milk increased, peak areas of pentanal, hexanal, and heptanal increased significantly (P,< 0.05) while those of dimethyl disulfide did not change significantly (P,> 0.05). Sodium azide prevented the formation of dimethyl disulfide in milk, implying that dimethyl disulfide can be formed through singlet oxygen oxidation (type II pathway). Addition of ascorbic acid and BHA reduced the formation of hexanal, heptanal, and dimethyl disulfide significantly (P,< 0.05). Generation mechanisms of pentanal seem to be different from those of hexanal and heptanal in milk. Both singlet oxygen oxidation (type II pathway) and free radicals (type I pathway) play important roles in the formation of light-induced volatiles in milk. [source] Sensory Characterization of Dry Gins with Different Volatile ProfilesJOURNAL OF FOOD SCIENCE, Issue 6 2008M. Riu-Aumatell ABSTRACT:, The aim of this study was the sensory characterization of dry gins in relation to their chemical volatile composition. The development of a specific vocabulary was necessary as a basis for quality control and to ensure the brand flavor integrity. The lexicon was obtained according to ISO 11035 (1994), on the basis of discussions between the panelists and the panel leader, reference materials, and an aroma wheel. Ten notes of the preliminary vocabulary were reduced by calculating the geometric mean (M) and applying ANOVA and principal component analysis. Finally, juniper, citric, aniseed, spice, and licorice were applied to describe 4 London Dry Gins (G1 to G4) and 2 gins with geographic indications (G5 and G6) by generic descriptive analysis (GDA). The latter were characterized by citric and juniper notes, respectively, while G1 was characterized by spice and aniseed attributes. Licorice was uniform in all of the samples. Chemical volatile composition of samples obtained by headspace-solid phase microextraction (HS-SPME) coupled with gas chromatography/mass spectrometry (GC/MS) was in agreement with the sensory results. [source] Optimisation of the headspace-solid phase microextraction for organomercury and organotin compound determination in sediment and biotaJOURNAL OF SEPARATION SCIENCE, JSS, Issue 4 2008Alejandra Delgado Abstract Headspace solid-phase microextraction was optimised for the simultaneous preconcentration of methylmercury (MeHg+), monobutyltin, dibutyltin, tributyltin, monophenyltin (MPhT), diphenyltin (DPhT), and triphenyltin (TPhT) from sediments and biota. Extraction time (3,24 min), extraction temperature (20,90°C), desorption time (1,10.4 min), desorption temperature (152,260°C), and sample volume (5,22 mL) were simultaneously optimised, while variables such as fibre type (30 ,m polydimethylsiloxane, PDMS), pH (acetic acid/sodium acetate, HOAc/NaOAc, 2 mol/L, pH , 4.8), the concentration of the derivatisation agent (sodium tetraethylborate, NaBEt4, 0.1% m/v), and the ionic strength (fixed by the buffer solution) were kept constant. The variables were optimised according to the experiments proposed by the MultiSimplex program and the responses were considered in order to establish the optimum conditions. The repeatability (relative standard deviation, RSD, 5,20.6%) and limits of detection (LODs, 0.05,0.97 ng/g) of the overall method were also estimated. The lowest precisions were obtained for DPhT and TPhT. The optimised preconcentration method was applied to the determination of MeHg+, butyl- and phenyltins in certified reference materials (IAEA-405 MeHg+ in estuarine sediment, BCR-646 butyl- and phenyltins in marine sediment, BCR-463 MeHg+ in tuna fish, DOLT-2 MeHg+ in dogfish liver, and BCR-477 butyltins in mussel tissue) by GC with microwave-induced plasma/atomic-emission detection. [source] | ||||||||||