Headspace solid-phase microextraction for direct determination of volatile phenols in cider.

Department of Chemistry, University of La Rioja, Logroño, La Rioja, Spain.
Journal of Separation Science (Impact Factor: 2.59). 11/2009; 32(21):3746-54. DOI: 10.1002/jssc.200900347
Source: PubMed

ABSTRACT A headspace solid-phase microextraction coupled to gas chromatography-tandem mass spectrometry (GC-MS/MS) method was optimised and validated for the determination of 4-ethylguaiacol, 4-ethylphenol, 4-vinylguaiacol and 4-vinylphenol, involved in the presence of Brett character, in ciders. The influence of different parameters on extraction efficiency (fibre coating, salt addition, exposure time, extraction temperature and sample volume/total volume ratio) was evaluated. Divinylbenzene/carboxen/PDMS was selected as extraction fibre and the other optimised parameters were as follows: 10 mL of cider, temperature 70 degrees C, extraction time 60 min and addition of 0.4 g/mL of NaCl. The proposed method showed satisfactory linearity. The detection limits obtained were 0.01 microg/L for 4-ethylguaiacol, 0.02 microg/L for 4-ethylphenol, 0.08 microg/L for 4-vinylguaiacol and 0.03 microg/L for 4-vinylphenol. These detection limits were lower than those obtained in previous studies on the determination of volatile phenols in other alcoholic beverages. Good recoveries of over 95% were observed for all compounds, and the repeatability obtained was considered acceptable, ranging between 4 and 10%. To demonstrate the feasibility of the procedure, the method was applied to the analysis of commercial ciders. To our knowledge, this is the first time that the headspace solid-phase microextraction procedure has been optimised to determine specifically the Brett character responsible compounds in cider.

1 Bookmark
  • [Show abstract] [Hide abstract]
    ABSTRACT: Odour-active compounds in strawberry vinegars were determined by gas chromatography equipped with an olfactometer using the modified frequency (MF) technique. The initial strawberry substrate was also analysed showing that ethyl 2-methylbutyrate, mesifurane, b-damascenone, furaneol and g-decalactone were preserved during the double fermentation process, presenting high MF values. The final aromatic profile of strawberry vinegars is formed both by compounds from the substrate and by those formed during alcoholic and acetous fermentation. Due to their high MF, a total of 12 odour zones, identified as acetic, butyric and isovaleric acids, methional, 3-nonen-2-one, 2-phenylethanol, pantolactone + furaneol, p-vinylguaiacol, sotolon, phenylacetic acid and vanillin, were considered as possible impact odorants of strawberry vinegars. Finally, all potential impact odorants with similar sensory descriptors were grouped into eight categories, these being: fruity, sweet, grassy, spicy, butter–lactic–cheesy, chemical, empyreumatic and miscellaneous. According to the MF percentage of these categories, grassy, fruity, sweet and spicy aroma seem to have the highest influence on the overall impression of strawberry vinegars.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Microextraction by packed sorbent (MEPS) was used for the determination of volatile composition of 29 French ciders samples from two regions: Normandy and Brittany. Extractions using a C18 sorbent were followed by GC-MS analyses for the identification of major volatile organic compounds (VOCs), and GC-FID analyses for the quantification of 19 selected major compounds. The method was found to be rapid and linear up to 300 mg/L for quite all compounds with an average relative standard deviation of 8.5% for tests of repeatability at low concentrations. The limit of detection (LOD) is below 0.1 mg/L except for three VOCs which exhibited much higher concentrations in samples. No significant difference in concentrations of higher alcohols were observed in the cider samples from two regions, however their concentrations were higher in hard ciders than sweet ciders. Acetates were found to be more present in sweet ciders from Normandy than those from Brittany reflecting important differences in the yeasts acting during the fermentation.
    Analytical methods 01/2014; DOI:10.1039/C3AY41385C · 1.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study evaluated the effect of the operations of selection, cleaning and sanitizing with sodium hypochlorite, on the populations of yeasts and lactic acid bacteria present in apple cider must, elaborated from commercial and industrial fruit. The microbial load differed between the cultivars and classes of fruit. The total populations of yeasts and lactic acid bacteria were higher in the industrial fruit. The operation of selection avoided cross-contamination and the presence of organic compounds that might react with the chlorine. Washing the apples decreased the populations of these microorganisms by one logarithmic cycle. Hierarchical cluster analysis indicated that sanitization was effective at a concentration of 100 mg/L for 5 min. The sanitizer was not effective in totally eliminating the microorganisms in populations greater than 104 CFU/mL. Selection and washing help reduce natural microbiota, making sanitization more effective, and positively affecting food safety and the quality of unpasteurized cider. Practical ApplicationsThis article presents the results, and a thorough discussion, of the use of pre-fermentation operations that can be used to reduce the microbial load of apple must, which is to be turned into cider. Among all the various techniques and controls, the three that were most noteworthy were analyzed (selection of fruits, washing and sanitizing with chlorine, followed by rinsing). These operations are critical control points, and if they are planned and monitored then can reduce or eliminate microorganisms (pathogens or not), eliminate or reduce the need for sulfite, facilitate the cleaning and disinfection of the environment and equipment, increase food safety, and ensure the production of high-quality unpasteurized cider.
    04/2014; 34(2). DOI:10.1111/jfs.12107

Full-text (2 Sources)

Available from
Oct 2, 2014