Browsing by Author "Rouseff, Russell L."

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Analysis of sulfur volatiles in coffee, wine, and grapefruit juice using GC-PFPD and GC-O
(Amer Chemical, 2009-08-16) Rouseff, Russell L.; Jabalpurwala, Fatima; Mahattanatawee, Kanjana; Gürbüz, Ozan; Uludağ Üniversitesi/Ziraat Fakültesi/Gıda Mühendisliği Bölümü.
Comparison of aroma volatiles in commercial Merlot and Cabernet Sauvignon wines using gas chromatography - olfactometry and gas chromatography - mass spectrometry
(Amer Chemical Soc, 2006-05-31) Rouseff, June; Rouseff, Russell L.; Gürbüz, Ozan; Uludağ Üniversitesi/Gıda Mühendisliği.; 0000-0001-7871-1628; 8528582100
Seventy-four aroma active compounds were observed in Merlot and Cabernet Sauvignon wines produced in California and Australia. Volatiles were sampled using solid phase microextraction and analyzed using time-intensity gas chromatography-olfactometry and gas chromatography-mass spectrometry (GC-MS). The most intense odorants were 3-methyl-1-butanol, 3-hydroxy-2-butanone, octanal, ethyl hexanoate, ethyl 2-methylbutanoate, beta-damascenone, 2-methoxyphenol, 4-ethenyl-2-methoxy-phenol, ethyl 3-methylbutanoate, acetic acid, and 2-phenylethanol. Aroma compounds were classified according to their aroma descriptor similarity and summed into nine distinct categories consisting of fruity, sulfury, caramel/cooked, spicy/peppery, floral, earthy, pungent/chemical, woody, and green/vegetative/fatty. Both Merlot and Cabernet Sauvignon wines were characterized by high fruity, caramel, green, and earthy aroma totals. Although there were distinct quantitative differences between Merlot and Cabernet wines, the relative aroma category profiles of the four wines were similar. Of the 66 volatiles identified by GC-MS, 28 were esters and 19 were minor alcohols. Between 81 and 88% of the total MS total ion chromatogram peak areas from each wine type were produced from only eight compounds: ethanol, ethyl octanoate, ethyl decanoate, ethyl acetate, 3-methyl-1-butanol, ethyl hexanoate, diethyl succinate, and 2-phenylethanol. Merlot wines from both Australia and California contained 4-5 times more ethyl octanoate than Cabernet Sauvignon wines from the same sources.
Gas chromatographic-olfactometric characterization of aroma active compounds in sun-dried and vacuum-dried tarhana
(Springer, 2004-05) Rouseff, Russell L.; Smoot, John M.; Dağdelen, A. Fatih; Göçmen, Duygu; Gürbüz, Ozan; Uludağ Üniversitesi/Ziraat Fakültesi/Gıda Mühendisliği Bölümü.; 0000-0001-7871-1628; 55967047900; 8528582100; 18133776200
The influence of drying methods on the aroma active volatiles of sun-dried tarhana (SDT) and vacuum-dried tarhana (VDT) were compared using headspace SPME, GC-O and GC-MS. Although vacuum drying reduced the total amount of volatiles as compared to SDT (total FID peak area), more aroma active material was retained with VDT (total olfactory peak area). Vacuum drying retained a greater number of aroma active components (41) whereas the sun-dried method retained only 23. Aldehydes were the largest single class of aroma compounds in both types of tarhana: 17 in VDT and 10 in SDT. Other differentiating aroma compounds include alcohols, terpenes, and phenols such as geraniol, terpinolene, and 4-vinylguaiacol among others. A total of 22 aroma active components were present in greater amounts in the VDT versus only four aroma compounds present in greater amounts in the SDT.
Identification of medicinal off-flavours generated by Alicyclobacillus species in orange juice using GC-olfactometry and GC-MS
(Wiley, 2005) Elston, Alison F.; Williams, T; Parish, Mickey E.; Rouseff, Russell L.; Göçmen, D.; Uludağ Üniversitesi/Ziraat Fakültesi/Gıda Mühendisliği Bölümü.
Aims: The objective of this study was to identify compounds responsible for medicinal off-flavours produced by different species and strains of Alicyclobacillus in orange juice using a combination of chromatographic-coupled olfactometric techniques and gas chromatography-mass spectrometry (GC-MS). Methods and Results: Each of five Alicyclobacillus strains was inoculated into separate juice samples and incubated up to 28 days at 45degreesC. Aroma compounds in the juice were analysed by GC-olfactometry (GC-O) and confirmed using GC-MS. GC-O identified three components that were described as medicinal/antiseptic. Microbial populations were enumerated at timed intervals by spiral plating onto Alicyclobacillus agar. Within 28 days incubation, all five strains produced medicinal off-aromas from guaiacol and at least one halogenated phenol. Significance and Impact of the Study: This is the first study to evaluate individual juice aroma components produced by Alicyclobacillus species using olfactometry and to demonstrate that at least three medicinal off-flavour compounds are associated with the growth of alicyclobacilli in orange juice.