Browsing by Author "Tokuşoǧlu O."

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    Rapid high performance liquid chromatographic detection of furosine (ε-n-2-furoylmethyl-l-lysine) in yogurt and cheese marketed in Turkey
    (2006) Tokuşoǧlu O.; Akalin A.S.; Unal K.
    Furosine (-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 (R2 = 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 mg100 g protein). All cheeses except pickled white showed furosine values between 182.16 ± 0.12 (canned tulum) and 261.32 ± 0.10 mg100 g protein (ripened kasar). The highest content of furosine was observed in whole yogurt (316.47 ± 0.17 mg100 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 (-deoxy-fructosyl-lysine) in yogurt and cheese samples. © 2006, Blackwell Publishing.
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    Occurrence of conjugated linoleic acid in probiotic yoghurts supplemented with fructooligosaccharide
    (2007) Akalin A.S.; Tokuşoǧlu O.; Gönç S.; Aycan S.
    A gas chromatographic procedure was used for the analysis of conjugated linoleic acid (CLA) isomers, c9t11-CLA and t10c12-CLA, in yoghurts containing Lactobacillus acidophilus or Bifidobacterium animalis and/or 2% fructooligosaccharide (FOS). Two groups of set yoghurts containing no supplement or 2% FOS were manufactured using three different starter cultures to determine the effect of processing, starter culture type, FOS supplementation and storage on CLA content. Processing of milk into yoghurt, the addition of FOS alone and storage for 28 d did not significantly affect CLA isomer formation in yoghurts (P > 0.05). However, significant increases in both isomer formation were obtained by using L. acidophilus or B. animalis in yoghurt manufacture (P < 0.05). The highest increases in c9t11-CLA isomer and total CLA content were found in yoghurts manufactured with L. acidophilus and FOS (2.71-fold increase in total CLA), and B. animalis and FOS (2.90-fold increase in total CLA) (P < 0.05). © 2007 Elsevier Ltd. All rights reserved.
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    Determination of sweetpotato [Ipomoea batatas (L.) Lam.] genotypes suitable to the Aegean region of Turkey
    (2011) Yildirim Z.; Tokuşoǧlu O.; Öztürk G.
    A 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; ßeta 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), ßeta carotene (7.04 mg /100 g) and vitamin A (11745 IU) for the Aegean Region.
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    The physicochemical, microbiological, organoleptic properties and antioxidant activities of functional cream cheeses fortified with lutein
    (2013) Tokuşoǧlu O.
    Functional cream cheeses were manufactured with 0, 0.5, 0.75, 1.5 and 3.0 mg lutein/100 g serving. Cheeses were monitored at 0, 1, 3, 5 and 7 weeks of storage. The pH value of an average of 5.5 provides softness and strong taste for the product. Descriptive sensory properties of lutein-fortified cream cheeses contained milky, buttery, salty and whey flavours. Cheese flavour was not affected by the differences in lutein levels. HPLC detection showed that lutein remained as stabile throughout about 6 weeks of storage. Physicochemical, microbiological and organoleptic data showed that 1.5 mg of fortification has preferred overall quality, and the best shelf life was recorded at week 3 of storage (P < 0.05). © 2013 Society of Dairy Technology.
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    The effect of high hydrostatic pressure processing on the extraction, retention and stability of anthocyanins and flavonols contents of berry fruits and berry juices
    (2013) Altuner E.M.; Tokuşoǧlu O.
    Anthocyanins 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. International Journal of Food Science and Technology © 2013 Institute of Food Science and Technology.
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    Effect of high hydrostatic pressure processing strategies on retention of antioxidant phenolic bioactives in foods and beverages - A review
    (Polish Academy Sciences, 2016) Tokuşoǧlu O.
    Phenolic compounds, especially flavonoids have health-promoting benefits that play some important roles in foods as visual appearance, taste, aroma and represent an abundant antioxidant component of the human and animal diet. High hydrostatic pressure processing (HHPP) conditions (300-700 MPa) at moderate initial temperatures (around ambient) are generally sufficient to inactivate vegetative pathogens for pasteurization processes, some enzymes, or spoilage organisms to extend the shelf-life. The aim of the review is to reveal the effect of high hydrostatic pressure processing strategies on the retention of antioxidant phenolic bioactives in foods and beverages. HHPP can increase extraction capacity of phenolic constituents, and ensure higher levels of preserved bioactive constituents. High pressure extraction (HPE) can shorten processing times, provide higher extraction yields while having less negative effects on the structure and antioxidant activity of bioactive constituents. HPE enhances mass transfer rates, increases cell permeability, increases diffusion of phenolics and retains higher levels of bioactive compounds. Total phenolics in HHPP-treated foods were either unaffected or actually increased in concentration and/or extractability following treatment with high pressure. © 2016 Özlem Tokuşoǧlu, published by De Gruyter Open 2016.