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    Chemical and microbiological status and volatile profiles of mouldy Civil cheese, a Turkish mould-ripened variety
    (Wiley, 2012) Cakmakci, Songul; Gundogdu, Engin; Hayaloglu, Ali A.; Dagdemir, Elif; Gurses, Mustafa; Cetin, Bulent; Tahmas-Kahyaoglu, Deren
    The objective of this study is to characterise the gross chemical and microbiological status and identify the volatile compounds of mouldy Civil cheeses. A total of forty-one samples were surveyed, and gross compositional status of the cheeses was (as mean values): 6.5 for pH, 6.2% for fat-in-dry matter, 51.8% for moisture and 15.3% for water-soluble nitrogen (as% of total nitrogen). Chemical composition of the cheese samples varied widely. Mouldy Civil cheese has similar pH values and moisture contents when compared with blue-type cheeses, but it has distinct feature for fat contents. The microbiological counts of the samples were found to be high and some samples contained coliform bacteria. A total of 95 volatiles, including esters (28), acids (6), ketones (12), aldehydes (3), alcohols (15), terpenes (10), sulphur compounds (3) and miscellaneous (18), were identified in the volatile fractions of the cheeses, and principal volatile groups were esters, alcohols and ketones.
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    Comparison of ?-aminobutyric acid and free amino acid contents of some common varieties of Turkish cheeses
    (Elsevier Sci Ltd, 2022) Ayag, Neslihan; Dagdemir, Elif; Hayaloglu, Ali Adnan
    A total of thirty cheese samples belonging to three varieties (Beyaz, Kasar and Tulum) with different technological traits were analysed for gamma-aminobutyric acid (GABA) and free amino acid (FAA) content. Microbiological and physicochemical status and soluble nitrogen fractions of cheese samples were examined to determine their effects on formation of GABA during ripening. The major FAA were His, Ile, Lys for Beyaz cheeses, Glu, His, Tyr, Ile, Phe, Trp for Kasar cheeses and His, Arg, Tyr, Ile, Leu, Trp for Tulum cheeses. Also, total free amino acid content was higher in Tulum cheeses. The GABA concentration ranged from 0.00 to 83.05 mg 100 g(-1), 1.65-45.79 mg 100 g(-1) and 0.20-21.06 mg 100 g(-1) for Beyaz, Kasar and Tulum cheeses, respectively. Cheese microflora, soluble nitrogen fractions, amino acid concentrations such as Glu and Gln and ripening time/conditions had a significant effect on formation of GABA. (C) 2021 Elsevier Ltd. All rights reserved.
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    Effect of Penicillium roqueforti and incorporation of whey cheese on volatile profiles and sensory characteristics of mould-ripened Civil cheese
    (Wiley, 2013) Cakmakci, Songul; Dagdemir, Elif; Hayaloglu, Ali A.; Gurses, Mustafa; Cetin, Bulent; Tahmas-Kahyaoglu, Deren
    In this study, four different types of mould-ripened Civil cheese were manufactured. A defined (nontoxigenic) strain of a Penicillium roqueforti (SC 509) was used as secondary starter for the manufacture of mould-ripened Civil cheese with and without addition of the whey cheese Lor; in parallel, secondary starter-free counterparts were manufactured. A total of 83 compounds were identified. Ketones, alcohols and esters were the principal classes of volatile components. Principal component analysis of the headspace volatiles grouped cheeses by age and type. P.roqueforti inoculated cheese was clearly separated from the other cheeses at 180days of ripening, and these cheeses were characterised with high levels of ketones (e.g., 2-butanone, 2-heptanone). Differences in the panel scores between the cheese samples were not significant during the first stage of ripening (up to 60days); as ripening proceeded, these differences were become evident and P.roqueforti inoculated cheeses received higher scores than others. Addition of Lor in the manufacture of mould-ripened Civil cheese caused lower points by the sensory panel, and the cheese inoculated with P.roqueforti and Lor-free was the best type of mould-ripened Civil cheese. The results showed that the use of P.roqueforti in the manufacture of mould-ripened Civil cheese has significant impact on the volatile profiles and sensory attributes.
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    The effect of pumpkin fibre on quality and storage stability of reduced-fat set-type yogurt
    (Wiley, 2017) Bakirci, Sumeyra; Dagdemir, Elif; Boran, Osman Seracettin; Hayaloglu, Ali Adnan
    In this study, the effect of pumpkin fibre (PF) on physicochemical, microbiological, rheological and microstructural characteristics of reduced-fat yogurt samples was investigated during storage. PF was added at three different concentrations (0.5%, 1.0% and 1.5%) to standardised (1.55% fat ratio) cow's milk. Plain yogurt (PF-free) was used for comparison. The addition of PF significantly affected total solid content, synaeresis, water-holding capacity, apparent viscosity and colour parameters (L*, a*, b*) of yogurt samples for all sampling time. The addition of PF caused a reduction in L* values (from 94.89 to 88.67), but caused an increase in a* (from -2.10 to + 4.22) and b* (from 10.79 to 25.88) values. Yogurts with PF exhibited lower synaeresis and more viscous structure than PF-free sample during storage. SEM images showed that distinctive microstructure profile was present between samples with or without PF. More filamentous structures and denser network were observed in the SEM images and these increased with increasing level of PF. Yogurt containing 1.0% PF showed a higher storage (G') (3687.87 at 21 day) and loss (G '') (543.10 at 21 day) moduli in comparison with other samples. In conclusion, the results revealed that PF improved the physical quality and contributed textural properties of half-fat yogurt.
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    Effects of Penicillium roqueforti and whey cheese on gross composition, microbiology and proteolysis of mould-ripened Civil cheese during ripening
    (Wiley-Blackwell, 2014) Cakmakci, Songul; Hayaloglu, Ali A.; Dagdemir, Elif; Cetin, Bulent; Gurses, Mustafa; Tahmas-Kahyaoglu, Deren
    Four different types of mould-ripened Civil cheese were manufactured. A defined (nontoxigenic) strain of a Penicillium roqueforti (SC 509) was used as the secondary starter with and without addition of the whey cheese (Lor); in parallel, secondary starter-free counterparts were manufactured. Chemical composition, microbiology and proteolysis were studied during the ripening. The incorporation of whey cheese in the manufacture of mould-ripened Civil cheese altered the gross composition and adversely affected proteolysis in the cheeses. The inoculated P.roqueforti moulds appeared to grow slowly on those cheeses, and little proteolysis was evident in all cheese treatments during the first 90days of ripening. However, sharp increases in the soluble nitrogen fractions were observed in all cheeses after 90days. Microbiological analysis showed that the microbial counts in the cheeses were at high levels at the beginning of ripening, while their counts decreased approximately 1-2logcfu/g towards the end of ripening.
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    Metabolite profiling of fermented milks as affected by adjunct cultures during long-term storage
    (Elsevier, 2023) Isik, Sumeyra; Dagdemir, Elif; Tekin, Ali; Hayaloglu, Ali Adnan
    The effects of starter strains (Lactiplantibacillus plantarum 156, Lactobacillus casei ATCC 334, Lactobacillus helve-ticus DPC 4571, and Streptococcus thermophilus 20S4) on the physicochemical and microbiological properties, volatiles, bioactive peptides, and gamma-aminobutyric acid (GABA) contents of fermented milks were evaluated during storage. The use of different adjunct culture combinations had no significant effect on the gross chemical composition. The bacterial strains remained highly viable in the fermented milk during storage. The peptide extracts exhibited a high ACE-inhibitory activity, which was particularly increased in the samples where L. casei ATCC 334 and L. helveticus DPC 4571 strains co-existed. Almost the same levels of antioxidant activity was observed in the peptides extracted from fermented milk. Peptide extracts showed a certain level of antimicrobial activitiy against Staphylococcus aureus ATCC 29213, Listeria monocytogenes ATCC 7644, Salmonella Typhimurium RSHMB 95091, and Escherichia coli O157:H7; however, no inhibitory activity was observed against Bacillus cereus BC 6230. Among the free amino acids, His, Arg, Ala, and Pro were predominant in the samples. Significant differences were observed between samples regarding GABA content, which increased with increasing levels of proteolytic activity. A total of 33 volatile compounds were identified in fermented milks, with acetone, 2,3-buta-nedione, acetoin, 2-heptanone, acetic and hexanoic acids being the predominant volatiles. These results demonstrate the multifunctional role of peptides and GABA extracted from fermented milk through the action of specific Lactobacillus strains. Therefore, such a functional fermented milk product can be used to reduce the risk of disease or improve specific physiological functions.
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    Morphological, Molecular, and Mycotoxigenic Identification of Dominant Filamentous Fungi from Moldy Civil Cheese
    (Int Assoc Food Protection, 2012) Cakmakci, Songul; Cetin, Bulent; Gurses, Mustafa; Dagdemir, Elif; Hayaloglu, Ali Adnan
    Moldy Civil is a mold-ripened variety of cheese produced mainly in eastern Turkey. This cheese is produced with Civil cheese and whey curd cheese (Lor). Civil cheese has had a geographical presence since 2009 and is manufactured with skim milk. In the production of Moldy Civil cheese, Civil cheese or a mixture of Civil and Lor cheese is pressed into goat skins or plastic bags and ripened for 3 months or longer. During the ripening period, natural contaminating molds grow on the surface of and inside the cheese. In this study, 186 mold strains were isolated from 41 samples of Moldy Civil cheese, and 165 of these strains were identified as Penicillium roqueforti. Identification and mycotoxicologic analyses were conducted using morphotypic and molecular methods. PCR amplicons of the ITS1-5.8S-ITS4 region were subjected to sequence analysis. This research is the first using molecular methods on Moldy Civil cheese. Mycotoxicologic analyses were conducted using thin-layer chromatography, and random amplified polymorphic DNA genotypes were determined using the ari1 primer. Of 165 isolates, only 28 produced no penicillic acid, P. roqueforti toxin, or roquefortine.
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    Mycotoxin production capability of Penicillium roqueforti in strains isolated from mould-ripened traditional Turkish civil cheese
    (Taylor & Francis Ltd, 2015) Cakmakci, Songul; Gurses, Mustafa; Hayaloglu, A. Adnan; Cetin, Bulent; Sekerci, Pinar; Dagdemir, Elif
    Mould-ripened civil is a traditional cheese produced mainly in eastern Turkey. The cheese is produced with a mixture of civil and whey curd cheeses (lor). This mixture is pressed into goat skins or plastic bags and is ripened for more than three months. Naturally occurring moulds grow on the surface and inside of the cheese during ripening. In this research, 140 Penicillium roqueforti strains were isolated from 41 samples of mould-ripened civil cheese collected from Erzurum and around towns in eastern Turkey. All strains were capable of mycotoxin production and were analysed using an HPLC method. It was established that all the strains (albeit at very low levels) produced roquefortine C, penicillic acid, mycophenolic acid and patulin. The amounts of toxins were in the ranges 0.4-47.0, 0.2-43.6, 0.1-23.1 and 0.1-2.3mgkg(-1), respectively. Patulin levels of the samples were lower than the others. The lowest level and highest total mycotoxin levels were determined as 1.2 and 70.1mgkg(-1) respectively. The results of this preliminary study may help in the choice of secondary cultures for mould-ripened civil cheese and other mould-ripened cheeses.