Browsing by Author "Tokusoglu, Ö"
Now showing 1 - 20 of 46
Results Per Page
Sort Options
Item Phytochemical Quality, Microbial Stability, and Bioactive Profiles of Berry-Type Fruits, Grape, and Grape By-Products with High-Pressure ProcessingTokusoglu, Ö; Swanson, BG; Canovas, GVBItem Retinol and α-tocopherol concentrations in breast milk of Turkish lactating mothers under different socio-economic statusTokusoglu, Ö; Tansug, N; Aksit, S; Dinc, G; Kasirga, E; Özcan, CRetinol and alpha-tocopherol levels in breast milk of Turkish mothers under different socio-economic status were investigated. Mature milk samples were collected from 92 lactating mothers living in Izmir and in Manisa, cities of Turkey, who were at 60-90 days of the lactating period. Socio-economic, anthropometric, and dietary data were collected by means of a questionnaire. The body mass index was used to determine the nutritional status. The retinol and alpha-tocopherol contents of breast milk were determined by high-performance liquid chromatography; the concentration of alpha-tocopherol was 9.84 mu g/ml whereas retinol levels were 81.5 mu g/100 ml. The questionnaire survey was used to determine the level of these vitamins in the daily ration of the women. No significant differences were found in terms of milk retinol and alpha-tocopherol levels for the variables income, educational level and mothers' body mass index.Item High-Pressure Processing for Improved Dairy Food QualityTokusoglu, Ö; Swanson, BG; Barbosa-Cánovas, GVItem CITRININ RISK IN BLACK AND GREEN TABLE OLIVES: SIMULTANEOUS DETERMINATION WITH OCHRATOXIN-A BY OPTIMIZED EXTRACTION AND IAC-HPLC-FDTokusoglu, Ö; Bozoglu, FMycotoxin citrinin (CIT) and ochratoxin A (OTA) were simultaneously identified using immunoaffinity column-high performance liquid chromatography with fluorescence detection (IAC-HPLC-FD) (Ex.333 nm; Em:495 nm) after an optimized extraction procedure. Both mycotoxins were eluted on a C(18) RP support (250 x 4.6 mm I.D., ODS2, 5 mu m particles) using an isocratic eluent consisting of acetonitrile/water/formic acid (60/38/2, v/v/v), acidified to pH 2.5 and pumped at a flow rate of 1.0 mL min(-1). The four categories of citrinin levels [0-0.55; 1.56-2.0; 0.66-2.64; 5.76-14.55 mu g kg(-1) of CIT] and three categories of ochratoxin levels [0 - < 0.1; 0.1-0.25; 0.30- 0.46 mu g kg(-1) of OTA] were found in 88 groups of olive samples. Recovery studies [y= 21416x - 7919.4 (R(2)=0.9998) for citrinin and y= 0.0001x + 0.0074 (R(2)=0.9999) for ochratoxin A] were performed and the mean analytical recoveries detected in CIT and OTA in table olives ranged from 92.65 - 96.83% and 88.92 - 95.58%, respectively. Limit of detection (LOD) was equivalent to 0.05 mu g/kg for both CIT and OTA. With the proposed method, CIT and OTA were both quickly determined in table olives and could be used to detect of mycotoxinic risks in a HACCP quality system of olive and olive-based food products.Item Improving Liquid Egg Quality by Pulsed Electrical Field ProcessingTokusoglu, Ö; Barbosa-Cánovas, GV; Zhang, HQItem The effect of high hydrostatic pressure processing on the extraction, retention and stability of anthocyanins and flavonols contents of berry fruits and berry juicesAltuner, EM; Tokusoglu, ÖAnthocyanins and flavonols are types of phenolic compounds. Previous researches showed that phenolic compounds are relevant to the quality of plant-derived foods and beverages. Any food-processing technologies, which can preserve phenolic compounds after processing, should be taken into account for increasing the food quality. High hydrostatic pressure processing (HHPP) is a novel nonthermal process. There are some researches about the effect of HHPP on total phenolic content, total monomeric anthocyanins, kaempferol, myricetin and quercetin contents of berry fruits and berry juices in the literature. These studies showed that HHPP could possibly have a success potential in increasing the extraction, retention and stability of anthocyanins and flavonols contents of berry fruits and berry juices by preserving phenolic compounds after food processing. The aim of this review is to put forward how high hydrostatic pressure processing affects extraction, retention and stability of anthocyanins and flavonols of berry fruits and juices.Item DETERMINATION OF SWEETPOTATO [Ipomoea batatas (L.) Lam.] GENOTYPES SUITABLE TO THE AEGEAN REGION OF TURKEYYildirim, Z; Tokusoglu, Ö; Öztürk, GA total of ten sweetpotato genotypes were grown in a field trial in 2003 and 2004 and certain agronomical and quality characteristics were determined. Local variety Hatay Kirmizi (Hatay Red) was selected as suitable to the Aegean Region for storage root number (7.7) and storage root yield (8.1 tons /ha) as well as acceptable quality characteristics: dry matter content: 41.8 %; sugar content: 2229.3 mg /kg; beta eta carotene 7.03 mg/100 g; vitamin A: 11716.3 IU; vitamin C: 38.6 Mg /100 g. Another introduced variety Regal was also selected for yield (6.6 ton /ha) and starch content (31.1 g/100 g), Beta carotene (7.04 mg /100 g) and vitamin A (11745 IU) for the Aegean Region.Item Quality, Safety, and Shelf-Life Improvement in Fruit Juices by Pulsed Electric FieldsTokusoglu, Ö; Odriozola-Serrano, I; Martín-Belloso, OItem A rapid high performance liquid chromatographic detection of furosine (ε-N-2-furoylmethyl-L-lysine) in pasteurized and UHT milksTokusoglu, Ö; Akalin, AS; Unal, MKFurosine, generated from the acid hydrolysis of the amadori compound during the early Maillard reaction, is a suitable indicator of the effect of heating treatments on milk quality. Furosine content in pasteurized and UHT milks marketed in Turkey was detected using ion-pair reversed-phase liquid chromatography (RP-HPLC). Calibration study (R-2=0.9999), analytical method validation and recovery studies (y = 5.315 x + 0.043 (R-2 = 0.9998)) gave satisfactory results A wide range of furosine content was found in UHT milks (49.68 +/- 0.10 to 213.38 +/- 0.07 mg 100 g(-1) protein) depending on the heat-treatment intensity. Pasteurized milks had lower content of furosine (3.79 +/- 0.01 and 5.88 +/- 0.02 mg 100 g(-1) protein). The method provides rapid, reproducible and accurate determination of this amadori compound in milk and dairy products and can be utilized as one of the most commonly used quality marker in dairy industry.Item HPLC-UV and GC-MS characterization of the flavonol aglycons quercetin, kaempferol, and myricetin in tomato pastes and other tomato-based productsTokusoglu, Ö; Ünal, MK; Yildirim, ZThe amounts of three flavonoids, quercetin, kaempferol, and myricetin, in tomatoes (Solanum lycopersicum L.) and tomato-based products produced in Turkey has been determined by reversed phase high-performance liquid chromatography (RPHPLC) with UV detection. The HPLC profiles of five types of tomato, one commercial composite tomato juice, and three types of tomato paste, were obtained after acid hydrolysis and extraction. The presence of the flavonol aglycons was confirmed by gas chromatography with mass spectrometric detection (GC-MS). Tomatoes and tomato-based products contained primarily quercetin, kaempferol, and the minor flavonol myricetin. The total flavonol aglycon content of different varieties of tomato varied from 3.1 to 10.0 mg kg(-1) of fresh weight. Tomato juice and tomato salsa were rich in total flavonols, containing 19.8 mg L-1 and 10.5-13.2 mg kg(-1), respectively. The method enabled accurate and reproducible quantitative analysis of these flavonols in tomatoes and tomato-based products.Item Determination of the phytoalexin resveratrol (3,5,4′-trihydroxystilbene) in peanuts and pistachios by high-performance liquid chromatographic diode array (HPLC-DAD) and gas chromatography-mass Spectrometry (GC-MS)Tokusoglu, Ö; Ünal, MK; Yemis, FThe phytoalexin resveratrol (3,5,4'-trihydroxystilbene) in edible peanut (Arachis hypogaea L.) and pistachio (Pistacia vera L.) varieties grown in Turkey was analyzed by high-performance liquid chromatographic diode array and gas chromatography-mass spectrometric detection. trans-resveratrol in six peanut varieties, five pistachio varieties, and four market samples ranged between 0.03 and 1.92 mu g/g. The qerezlik 5025 peanut (1.92 +/- 0.01 mu g/g) and Ohadi pistachio genotype (1.67 +/- 0.01 mu g/g) had significantly higher trans-resveratrol contents. Peanuts contained 0.03-1.92 mu g/g (av = 0.84 mu g/g) of trans-resveratrol, whereas pistachio contained 0.09-1.67 mu g/g (av = 1.15 mu g/g). With exposure to UV light for 1 min, trans-resveratrol concentrations of samples ranged from 0.02 to 1.47 mu g/g and those of cis-resveratrol from 0.008 to 0.32 mu g/g. The occurrence of resveratrol in peanut and pistachio was confirmed by total ion chromatograms (TIC) of bis[trimethylsilyl]trifluoroacetamide derivatives of resveratrol isomers and comparison of the mass spectral fragmentation data with those of a resveratrol standard. Formation of the cis-isomer in pistachios was higher than in peanuts.Item Rapid high performance liquid chromatographic detection of furosine (ε-N-2-furoylmethyl-L-lysine) in yogurt and cheese marketed in TurkeyTokusoglu, Ö; Akalin, AS; Unal, KFurosine (epsilon-N-2-furoylmethyl-L-lysine) content determination in the yogurt and different cheese types (pickled white, kasar, processed, canned tulum, blue-veined and mozzarella cheeses) marketed in Turkey was performed using ion-pair reversed-phase high performance liquid chromatography (RP-HPLC). Calibration study (R-2 = 0.9999), analytical method validation and recovery studies gave satisfactory results. The lowest furosine values were observed in pickled white cheeses (5.35 +/- 0.01 to 7.28 +/- 0.02 mg/100 g protein). All cheeses except pickled white showed furosine values between 182.16 +/- 0.12 (canned tulum) and 261.32 +/- 0.10 mg/100 g protein (ripened kasar). The highest content of furosine was observed in whole yogurt (316.47 +/- 0.17 mg/100 g protein) which could be because of severe heat treatment and the addition of milk powder during the manufacturing process. The method provides a rapid, reproducible and accurate determination of this Amadori compound (epsilon-deoxy-fructosyl-lysine) in yogurt and cheese samples.Item Simultaneous differential pulse polarographic determination of cadmium, lead, and copper in milk and dairy productsTokusoglu, Ö; Aycan, S; Akalin, S; Koçak, S; Ersoy, NThe contents of potentially toxic elements lead and cadmium and the essential element copper in various milk and dairy products consumed in Turkey were determined by differential pulse polarography (DPP), primarily to assess whether the intakes comply with recommended desired concentrations for essential and permissible levels for toxic elements. A simple and rapid DPP method has been developed for the simultaneous determination of cadmium, lead, and copper in samples. Using the differential pulse mode, half-wave peak potentials as E-1/2 were -0.58, -0.40, and -0.07 V for cadmium (Cd), lead (Pb), and copper (Cu), respectively. Marketed formulations of dairy products have been analyzed by calibration and standard addition methods. Recovery experiments were found to be quantitative. The linear domain ranges were 0.00-674.28 mug/L for Cd (R-2 = 0.9999), 0.19-2.94 mg/L (p < 0.01) for Pb (R-2 = 0.9997), and 0.41 -133.46 mug/L for Cu (p < 0.01) (R-2 = 0.9999). The studies have shown that the method is a rapid, reproducible, and accurate determination of these elements in milk and dairy products and can be used in the analysis of marketed formulations in the milk and dairy industry.Item Introduction to Improving Food Quality by Novel Food ProcessingTokusoglu, Ö; Swanson, BGItem Detection of biologically active isomers of conjugated linoleic acid in kaymakAkalin, AS; Tokusoglu, Ö; Gönç, S; Ökten, SNumerous physiological effects are attributed to conjugated linoleic acids (CLA). Biologically active isomers of CLA (cis-9, trans-11 (C 1 8 : 2) and trans-10, cis-1 2 (C 1 8 : 2)) have been reported to have anticarcinogenic, antioxidative and antiatherosclerotic properties. Relatively rich sources of CLA include milk fat-containing foods such as kaymak. Kaymak is a kind of concentrated cream which is traditionally manufactured from buffalo or cow's milk mainly in Turkey,. The objective of this study was to determine CLA concentrations during kaymak production. Kaymak was manufactured from cow's milk which was enriched with unfermented cream. Biologically active isomers of CLA in raw milk, cream and kaymak were analyzed using gas chromatography. The method was quick, repeatable and sensitive for the CLA determination of samples. Significant differences were found among the concentrations of both isomer and total CLA during the production process (p < 0.01). The total GLA contents of raw milk, cream and kaymak were determined as 0.08 +/- 0.02, 0.234 +/- 0.04 and 0.091 +/- 0.08 g/ 100 g lipid, respectively.Item Proximate chemical composition, amino acid and fatty acid profiles of sesame seed floursTokusoglu, Ö; Ünal, MK; Alakir, IThe proximate composition, amino acid contents and fatty acid (FA) profiles of flours prepared from 14 sesame (Sesamum indicum L.) seed grown in Turkey were determined. Sesame seed flours (SSF) contained high value of crude protein in the range of 19.12 to 25.35% (p<0.01). Digestible protein concentration was also high (16.88-25.35%) (p<0.01). Ether extracts were 51.05-60.81% (p<0.01). The moisture contents were in the range of 3.10-4.60 (p<0.01) and the ash contents ranged from 2.88 to 5.28% (p<0.01) while crude fiber ranged between 3.86 and 5.16% (p<0.01). Total carbohydrate varied from 5.24 to 9.84% (p<0.01). Reducing sugars were 3.96-6.87% (p<0.01). Essential amino acid contents of SSF were of high levels. SSF are good sources of methionine (3.18-3.62 g/16 g N), lysine (2.23-4.62 g/16 g N), cysteine (2.93-3.88 g/16 g N) (p<0.01).Fatty acids, (C14:0, C16:0, C16:1n-7, C18:0, C18:1n-9, C18:2n-6, C18:3n-3 C20:0, C20:1) of these flours were obtained in percentage of total fat (0<0.01). Linoleic acid was the major unsaturated fatty acid (41.65-44.97%) and polyunsaturated fatty acid (PUFA) contents were high (p<0.01). The SSF are functional foods for nutrition and utilization.Item High hydrostatic pressure effects on mold flora, citrinin mycotoxin, hydroxytyrosol, oleuropein phenolics and antioxidant activity of black table olivesTokusoglu, Ö; Alpas, H; Bozoglu, FHigh hydrostatic pressure (HHP) as a non-thermal technology is an effective tool for microbiologically safe and shelf-stable fruits Mycotoxin citrinin (CIT) is a toxic secondary metabolite, especially produced from filamentous fungus Penicillium citrinum and is also produced by other species of Penicillium. Aspergillus, and Monascus that are able to develop on olive after harvest, during brine and storage of olives Nutritional benefits of olive fruit are mainly related to phenolics such as hydroxytyrosol, oleuropein and antioxidative effects. With HHP application of olives, total mold was reduced to 90% at 25 degrees C whereas it was 100% at 4 degrees C based on Rose-Bengal Chloramphenicol Agar (RBCA) Total Aerobic-Mesofilic Bacteria load was reduced to 35-76% at 35 +/- 2 degrees C based on the Plate Count Agar (PCA). Citrinin load was reduced to 64-100% at 35 +/- 2 degrees C 2.5, 10, 25, and 100 ppb of spiked citrinin in sample were degraded as %56; %37, %9, and %1 3, respectively. 2 5 ppb and less citrinin contamination in table olive were degraded more (56%). Total phenolics were increased to 2 1-2 5-fold after HHP (as mgGA/100 g) Hydroxytyrosol in olives increased on average 0 8-2.0-fold whereas oleuropein decreased on average 1-1.2-fold after HHP (as mg/kg dwt) Antioxidant activity values varied from 17 238 to 29.344 mmol Fe2+/100 g for control samples whereas 18.579-32 998 mmol Fe2+/100 g for HHP-treated samples HHP could be used in the olive industry as non-thermal preservation (C) 2009 Elsevier Ltd All rights reserved.
- «
- 1 (current)
- 2
- 3
- »