Gıda Mühendisliği Bölümü Koleksiyonu

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https://hdl.handle.net/20.500.12428/2651

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Zeytinyağı Aroma Kimyası ve Duyusal Değerlendirilmesi
(Sidas Medya A.Ş., 2004) Yılmaz, Emin; Öğütçü, Mustafa
Flavor and aroma are essential quality factors for the food materials. Over 100 volatiles have been determined in olive oils, and of them 30 has found to contribute the perceived aroma of the oil. Determination of the sensorials terms of the measured volatiles, comparison of the samples, conversion of the consumer preference language to understantable chemical terms are also imperative.
Trends in Sustainability and Innovative Food Packaging Materials: An Overview
(Sidas Medya A.S., 2024) Caner, Cengiz; Yüceer, Muhammed; Harte, Bruce
Globally, 1.3 billion tons of food are wasted or lost every year. This loss is valued at US $2.6 trillion and accounts for 8-10% of greenhouse gas emissions (GHG). Food waste is a significant source of greenhouse gas emissions and results in a waste of natural resources. Therefore, reducing food waste can help diminish GHG emissions, improve food security, and promote healthy food systems. Packaging plays an important role in protecting food, enhancing quality and safety, and reducing food losses. Innovative and sustainable packaging strategies are necessary to decrease waste accumulation, particularly of plastics, safeguard food quality and safety, and reduce food losses and waste. Sustainable packaging aims to enhance the effectiveness of design and the use of environmentally friendly materials. This review provides an overview of the sustainable status of common packaging materials such as plastic, glass, metal, and paper/cardboard based on the circular economy, which includes recycling, reuse, composting, and bio-based packaging. The study examines new developments in food packaging materials in response to the growing demand for environmentally sustainable alternatives. Several applications from food companies and sustainable studies are discussed regarding continuous availability without impacting the environment. Ongoing research and technological advancements, such as material reduction, the development of innovative new materials like bioplastics, and improvements in recycling, will contribute to increasing the acceptance of sustainable packaging. Definitions, requirements, limitations, legislation, and applications of sustainable packaging are explored. Sustainable packaging can stimulate economic growth and offer new opportunities for companies, notably by helping the environment and reducing the carbon footprint. However, the cost of sustainable packaging can still be challenging for small businesses. Determining whether consumers are willing to pay more for sustainable packaging is also crucial in this transition. © 2024 Sidas Medya A.S.. All rights reserved.
Optimization of bioethanol production from sugar beet processing by-product molasses using response surface methodology
(Springer Science and Business Media Deutschland GmbH, 2025) Altınışık, Sinem; Nigiz, Filiz Uğur; Gürdal, Savaş; Yılmaz, Kadir; Tuncel, Necati Barış; Koyuncu, Sermet
Bioethanol production from renewable biomass sources has garnered significant interest due to its potential as a sustainable alternative to fossil fuels. In this study, we investigated the optimization of bioethanol production from molasses, a by-product of the sugar production process using Saccharomyces cerevisiae through Response Surface Methodology (RSM). Initially, the fermentation process was optimized using RSM, considering four independent variables: substrate concentration, pH, temperature, and fermentation time. Subsequently, the effects of these variables on bioethanol yield were evaluated, and a quadratic model was developed to predict the optimum conditions. Analysis of variance (ANOVA) indicated a high coefficient of determination (R2) for the model, suggesting its adequacy for prediction. The optimized conditions for bioethanol production were determined as follows: substrate concentration of 200 g L−1, pH of 5.0, temperature of 30 °C and fermentation time of 72 h. Under these conditions, the predicted bioethanol yield was 84%. Overall, this study demonstrates the successful application of RSM for optimizing bioethanol production from molasses using S. cerevisiae, highlighting its potential as a promising feedstock for biofuel production. © The Author(s) 2024.
The Effect of Germination on Antinutritional Components, In Vitro Starch and Protein Digestibility, Content, and Bioaccessibility of Phenolics and Antioxidants of Some Pulses
(John Wiley and Sons Inc, 2025) Yılmaz Tunçel, Neşe; Polat Kaya, Havva; Sakarya, Fatma Betül; Andaç, Ali Emre; Korkmaz, Fatma; Özkan, Gülay; Tuncel, Necati Barış
The objective of this study was to investigate the impact of 24- and 48-h germination on antinutrient levels (phytic acid, trypsin inhibitors, saponins, and tannins), in vitro starch and protein digestibility, and the content and bioaccessibility of phenolic compounds and antioxidants in chickpeas, peas, mung beans, and lentils. Germination resulted in reductions of phytic acid by up to 75.65% and trypsin inhibitor activity by up to 39.20% in the pulses studied. In contrast, saponin levels showed a significant increase, rising nearly threefold with germination, while mung beans exhibited an exceptional 27-fold increase. Tannins decreased in lentils (2.6-fold) and mung beans (5.8-fold), increased in peas (1.6-fold), and remained unchanged in chickpeas following germination. In vitro protein digestibility generally increased with germination, reaching up to 4.40%, except in peas, where a decline was observed. Germination significantly enhanced total digestible starch content while reducing resistant starch in all pulses except chickpeas. Mung beans exhibited the highest total phenolic content and antioxidant capacity, followed by lentils. Although germination significantly elevated total phenolic content in all pulses, this increase did not always align with antioxidant capacity outcomes. Additionally, germination led to a decline in the bioaccessibility of phenolics. However, the amount of phenolic compounds progressively increased during gastric and intestinal digestion, with intestinal digestion further enhancing the total antioxidant capacity of the pulses. © 2025 The Author(s). Food Science & Nutrition published by Wiley Periodicals LLC.
The effect of simulated vibration frequency on the physico-mechanical and physicochemical properties of peach during transportation
(Elsevier Ltd., 2021) Dağdelen, Çiğdem; Aday, Mehmet Seçkin
Loss in fresh fruit and vegetables during transportation occurs mainly due to their susceptibility to mechanical damage. The quality loss caused by this damage depends on the shock and vibration frequencies. In this study, the effect of different vibration frequencies (5 Hz, 10 Hz, and 15 Hz) on the physico-mechanical and physico-chemical properties of peach was investigated. The parameters such as energy absorption, mechanical hysteresis, and deformation volume were increased whereas mean geometric diameter, surface area, volume, degree of elasticity, deformation energy, and modulus of elasticity were decreased. Regarding physicochemical properties, pH and total soluble solid parameters increased whereas lightness (L*) value of peach decreased. The highest level of damage and mold growth were observed on the peach treated with 15 Hz frequency followed by 10 Hz and 5 Hz, respectively. The effect of all the frequencies on the physico-mechanical and physico-chemical properties of peach was statistically different. The results indicated that the increase in the vibration frequency causes higher mechanical damage in peach.
Optimization of pretreatment and enzymatic hydrolysis conditions of tomato pomace for production of alcohols and esters by Kluyveromyces marxianus
(Elsevier Ltd., 2021) Kılmanoğlu, Hilal; İşleten Hoşoğlu, Müge; Güneşer, Onur; Karagül-Yüceer, Yonca
Tomato pomace (TP) is generated as a natural by product in a significant amount in the tomato processing industry, and it is a good source of lignocelluloses to produce some high-value products from fermentable sugars (FS). The present study was performed to produce FS by using either ultrasound-assisted dilute acid (UADA) or heat-treated dilute acid (HTDA) pretreatments of TP followed by enzymatic hydrolysis (EH). When HTDA and UADA were compared in terms of FS (g/L) concentration, HTDA pretreatment generally produced more FS content than UADA. The optimum conditions for HTDA pretreatment were the application of 2.5% H2SO4, 10% (w/v) solution of TP, and heating at 121 °C for 6 min, which yielded 31 g/L FS concentration. Beside the optimized conditions for EH of HTDA, pretreated TP required 1.5% of enzyme concentration and 6 h of hydrolysis time. In conclusion, the most abundant volatile organic compounds (VOCs) produced by K. marxianus in final tomato pomace hydrolysate (TPH) were isoamyl alcohol, phenyl ethyl alcohol, ethyl acetate and phenyl ethyl acetate in a 5-L bioreactor. Nine descriptive sensory terms were developed to characterize fermented TPH. The rose and sweet floral aromas were defined as aroma characteristics for TPH fermented by K. marxianus.
Soğuk Baskı Yöntemiyle Üretilmiş Greyfurt Çekirdek Yağındaki Acılığın Yıkama/Ekstraksiyon Teknikleriyle Giderilmesi
(Sidas Medya A.S., 2021) Deviren, Ayten; Ok, Selçuk; Yılmaz, Emin
In this study, different extraction and washing techniques used to remove the bitterness of grapefruit seed oil produced by cold pressing technique were compared. Some physico-chemical properties, oil components and sensory properties of the treated samples were determined. While the free fatty acidities of oils decreased with the treatments, there was a slight increase in the peroxide values of oils. As a result of the treatments, the ratio of total unsaturated fatty acids, tocopherol, and phytosterol concentrations decreased significantly (p<0.05). It is thought that these minor components, which have high nutritional value, leaked into the solvent phase. Naringin, which has a very bitter taste, was measured as 102.6 mg/kg in the control sample and reduced to 74.8 mg/kg by caustic washing and 32.3 mg/kg by extraction with ethanol. Similarly, neohesperidin, which has also a bitter taste, was completely removed from oils by these two treatments. Sensory score of bitterness was determined as 9.8 in the control sample, and it was reduced to 5.4 with caustic washing, and 2.6 with ethanol extraction. Similarly, raw vegetables, astringency, menthol and throat burning scores were also reduced with treatments. As a result, it was observed that the ethanol extraction technique was successful in removing the bitterness of oils.
MİKRODALGA DESTEKLİ HİDRODİSTİLASYON YÖNTEMİYLE ELDE EDİLEN PELARGONIUM GRAVEOLENS (ITIR) ESANSİYEL YAĞININ KARAKTERİSTİK BAZI ÖZELLİKLERİ
(Gıda Teknolojisi Derneği, 2021) Aydınlık, Pelin; Karagül Yüceer, Yonca
Bu çalışmada Pelargonium graveolens’den (ıtır) elde edilen esansiyel yağın karakteristik özellikleri incelenerek doğal katkı maddesi olarak elma suyunda kullanılabilirliği araştırılmıştır. Esansiyel yağ üretiminde mikrodalga destekli hidrodistilasyon yöntemi kullanılmış ve %1.75 verimle esansiyel yağ üretimi gerçekleştirilmiştir. Uçucu bileşenlerin tanımlanması amacıyla gaz kromatografisi kütle spektrometresi kullanılmıştır. Itır esansiyel yağının temel uçucu bileşenleri sitronelil format, izomenton, linalol, sitronelol ve geraniol olarak belirlenmiştir. Esansiyel yağın antioksidan aktivitesi 0.54 mM troloks/mL yağ bulunmuştur. Esansiyel yağın antibakteriyel etkisinin Escherichia coli’ye kıyasla Staphylococcus aureus üzerine daha fazla olduğu saptanmıştır. Itır esansiyel yağı ilave edilmiş elma suyunun mikrobiyel yükünde depolama boyunca düşüş olduğu belirlenmiştir. Ayrıca esansiyel yağ ilave edilen elma suyunun duyusal özellikler bakımından da kabul edilebilir olduğu tüketici testiyle ortaya koyulmuştur.
TİRE ÇAMUR PEYNİRİNİN BAZI FİZİKOKİMYASAL VE DUYUSAL ÖZELLİKLERİ
(2021) Karaalioğlu, Onur; Günay, Ezgi; Karagül Yüceer, Yonca
Bu çalışmanın amacı, İzmir’in Tire ilçesinde geleneksel olarak üretimi gerçekleştirilen Tire Çamur peyniri’nin bazı fizikokimyasal ve duyusal özelliklerinin belirlenmesidir. Bu çalışma kapsamında analizleri gerçekleştirilen Tire Çamur peyniri örnekleri arasında bileşim bakımından önemli farklılıklar olduğu saptanmıştır. Gaz kromatografisi-kütle spektrometrisi (GC-MS) vasıtasıyla gerçekleştirilen kromatografik analizlerde toplam 29 adet uçucu bileşen tespit edilmiştir. Duyusal değerlendirmeler sonucunda ise pişmiş, peynir altı suyu, kremamsı, fermente ve sütümsü yoğun olarak algılanan aromatikler olarak belirlenmiştir. Elde edilen veriler kapsamında, ürünün endüstriyel boyutlarda üretim standardizasyonunun sağlanmasıyla birlikte tüketiciler için ürünün kaynağını gösteren coğrafi işaret alınmasının; üreticiye, üretildiği bölgeye ve ülkemize önemli ekonomik katkı ve katma değer sağlama potansiyeline sahip olacağı düşünülmüştür.
Çanakkale bölgesinden alınan midye ve deniz suyu örneklerinin mikrobiyolojik kalitelerinin belirlenmesi
(2021) Tosun, Melike Nur; Taylan Yalçın, Gizem; Zorba, Nükhet Nilüfer
Bu çalışmada Çanakkale bölgesinde belirlenen 9 farklı istasyondan toplanan 536 midye örneğinin ve her istasyondan alınan deniz suyunun mikrobiyolojik kalitesi belirlenmiştir. Midye örneklerinin toplam mezofilik aerobik bakteri yükünün en yüksek Merkez İskele istasyonunda (3.56 log kob/g) olduğu belirlenmiştir. En yüksek E. coli varlığı ise Gelibolu istasyonunda (1.99 log kob/g) saptanmıştır. Midyelerin mikrobiyel yüklerinin toplandıkları istasyonlar arasında istatistiksel anlamda farklı olmadığı (P>0.05) görülmüştür. Midyelerin toplam mezofilik aerobik bakteri sayısı ile toplandıkları deniz suyunun toplam mezofilik aerobik bakteri sayısı arasında pozitif yönde korelasyon tespit edilmiştir (P<0.05). Gelibolu ve Lapseki istasyonlarındaki mikrobiyel yükün diğer istasyonlara göre daha yüksek olduğu saptanmıştır. Genel olarak değerlendirildiğinde Gelibolu ve Lapseki bölgesi haricinde Çanakkale boğazının farklı noktalarından alınan midyelerin mikrobiyel kalitesinin yasal sınırlar içerisinde olduğu belirlenmiştir.
Yayıkaltı içeceğinin fizikokimyasal ve duyusal özellikleri ile uçucu bileşenlerinin belirlenmesi
(2021) Öğe, Çisem; Karagül Yüceer, Yonca
Bu çalışmada yayıkaltı suyunun farklı mikroorganizmalarla fermantasyonu ile üretilen içeceklerin karakteristik bazı özelliklerinin belirlenmesi amaçlanmıştır. Toz halindeki yayıkaltının %10’luk çözeltisi ile belirli oranlarda (% 0, 25, 50, 75, 100) çiğ süt karışımına ısıl işlem uygulandıktan sonra örneklere L. acidophilus (LA) kültürü ve L. acidophilus, Bifidobacteria ile S. thermophilus karışık kültürü (ABT) ilave edilerek 37°C’de, yaklaşık 4.8 pH’ya kadar inkübe edilmiştir. Ürünlerin fizikokimyasal ve duyusal özellikleri ve uçucu bileşenleri depolama süresince belirlenmiştir. İçeceklerde yayıkaltı suyu oranı azaldıkça yağ, kurumadde ve protein oranları artmıştır. Örneklerde uçucu bileşenler gaz kromatografisi kütle spektrometrisi kullanılarak belirlenmiştir. Tüm örneklerde belirlenen uçucu bileşikler aseton, 2,3-butandion, asetoin, toluen, 2-heptanon, limonen, ökaliptol, asetik asit ve butanoik asit olmuştur. Yayıkaltı içeceklerinde pişmiş, kremamsı, süthane/sütümsü, fermente, karton, yosun, sabunsu, depo, tatlı, tuzlu, buruk ve acı terimleri duyusal değerlendirmeler sonucunda belirlenmiştir.
Kitosan bazlı etil pirüvat filmlerin fizikokimyasal, antioksidan, antimikrobiyal ve anti-quorum sensing özelliklerinin belirlenmesi
(2021) Kaya, Burcu; Zorba, Nükhet Nilüfer; Caner, Cengiz
Bu çalışmada kitosan film formülasyonuna iki farklı (%1 ve %3) konsantrasyonda etil pirüvat ilave edilerek, çevre dostu bir ambalaj materyali geliştirilmesi amaçlanmıştır. Bu kapsamda hazırlanan film örneklerinin nem, suda çözünürlük, görünür yoğunluk, renk, biyobozunurluk, kimyasallara karşı direnç özellikleri belirlenerek, filmlerin yüzey morfolojisi SEM, fonksiyonel grupları ise FTIR ile karakterize edilmiştir. Ayrıca film örneklerinin antimikrobiyal ve anti-quorum sensing aktivitesi disk difüzyon yöntemi ile belirlenmiştir. Sonuç olarak formülasyona etil pirüvat eklenmesiyle kitosan filmin nem içeriği, görünür yoğunluğu, biyobozunurluğu ve antioksidan aktivitesi artmıştır. SEM görüntüleri incelendiğinde ise etil pirüvatın, kitosan filmlerde gözenekli yapı oluşumuna neden olduğu gözlemlenmiştir. Film örnekleri Escherichia coli O157:H7, Bacillus cereus, Staphyloccocus aureus, Alternaria arborescens, Aspergillus flavus, Penicillium digitatum, Penicillium citrinum ve Penicillum expansum suşlarına karşı antimikrobiyal etki göstermiştir. Buna ek olarak tüm film örneklerinin anti-quorum sensing aktivite gösterdiği tespit edilmiştir. Elde edilen verilere göre özellikle CS-EP1 filminin, doğa dostu alternatif gıda ambalajı olarak kullanılabileceği belirlenmiştir.
Characterization of aroma-active compounds, sensory properties, and proteolysis in Ezine cheese
(Elsevier Science Inc, 2009) Karagül Yüceer, Yonca; Tuncel, Barış; Güneşer, Onur; Engin, Burcu; İşleten, Müge; Yaşar, Kurban; Mendeş, Mehmet
Ezine cheese is a white pickled cheese ripened in tin-plate containers for at least 8 mo. A mixture of milk from goat, sheep, and cow is used to make Ezine cheese. Ezine cheese has geographical indication status. The purposes of this study were to determine and compare the changes in basic composition, aroma, and sensory characteristics, and proteolytic activity of Ezine cheese stored in tinplate containers and plastic vacuum packages during storage. Aroma-active compounds were determined by thermal desorption gas chromatography olfactometry. To evaluate the proteolytic activity, casein and nitrogen fractions were determined. The results indicated that compounds identified at high intensities were dimethyl sulfide, ethyl butyrate, hexanal, ethyl pentanoate, (Z)-4-heptenal, 1-octen-3-one, acetic acid, butyric acid, and p-cresol. Characteristic descriptive terms were cooked, whey, creamy, animal-like, sour, and salty. The level of proteolysis increased in Ezine cheese during storage. Ezine cheese can be ripened in small-size packaging after 3 mo of storage. Approximately 6 mo is sufficient to produce the characteristic properties of Ezine cheese.
Sensory characteristics of Ezine cheese
(Wiley, 2007) Karagül Yüceer, Yonca; İşleten, Müge; Uysal Pala, Çiğdem
Ezine cheese is a full-fat, white pickled cheese ripened in tinplate containers. A mixture of milks from goat, sheep and cow is used to make Ezine cheese. It has its own characteristic taste and aroma that differ from other white cheeses. In this study, the chemical composition and sensory attributes of Ezine cheese were characterized. A descriptive sensory evaluation technique was used to determine flavor and texture characteristics. Representative Ezine cheeses (22) were provided by local producers. A highly trained (n = 9) panel generated the descriptive terms and identified the references. Fourteen flavors and 10 texture terms were developed to describe Ezine cheese flavor and texture. Some characteristic flavor and taste descriptors for Ezine cheese were free fatty acids, cooked, creamy, whey-like, goaty, salty and sour. Cheese texture was evaluated using hand, mouth and residual techniques. Texture analysis indicated that Ezine cheese had soft and semi-hard texture properties. In general, most of the Ezine cheeses showed similarities in terms of hand firmness, mouth firmness, fracturability and number of particles attributes.
Comparative analysis of essential oil oleogels containing beeswax and sunflower wax with petrolatum gels
(Wiley, 2024) Çokay, Hatice; Çelebi Uzkuç, N. Merve; Karagül Yüceer, Yonca; Öğütcü, Mustafa
In this study, three different oil (black seed, St. John's Wort, and grape seed oils [GSO]) oleogels, which are especially used in complementary medicine, were produced with natural waxes (sunflower and beeswax [BW]). The physicochemical, textural, thermal, and structural features and volatile composition of the oleogels were determined and compared with commercial petrolatum gels (control sample). The sunflower and BW gels had a higher melting point than the petrolatum gels. Particularly, the firmness values of the fresh sunflower and BW oleogels were close to the petrolatum gels, except for the BW-based St John's Wort and GSO gels. The firmness and stickiness values of the oleogels and the control samples increased in relation to the storage period. The increase in firmness value was less in the sunflower wax than in the BW and control samples. All sunflower, BW and petrolatum gels exhibited the beta ' form. Volatile component data showed that different waxes have different volatile adsorption capacities. As a result, natural wax oleogels produced with various essential oils could be an alternative to similar products used in the cosmetics, pharmacology, and food supplement industries, which are already commercially available.Practical applications: (Oleogels have become a popular technique for structuring oils in recent years. In this way, oleogels are considered an alternative to solid fat such as margarine, butter, and shortening and an oil-restricting agent against oil leakage in oil-based foods. Consumers establish a close relationship between their own health and the foods they consume and the cosmetics they use. This situation has led to an increasing interest in natural products. Essential oils (EOs) are used in many fields, ranging from cosmetics to complementary medicine. In this context, essential oleogels produced with natural waxes were compared with the commercial products, revealing their potential for use in both cosmetic and food supplements. EO-oleogels represent a new approach to the oleogel product range with high commercialization potential for related industries.) Graphical Abstract: The textural and structural properties of the essential oil oleogels prepared with beeswax and sunflower wax were almost similar to their commercial counterparts such as petrolatum. image
Characterisation of aroma-active compounds, chemical and sensory properties of acid-coagulated cheese: Circassian cheese
(Wiley, 2011) Güneşer, Onur; Karagül Yüceer, Yonca
The objectives of this study were to determine basic composition, aroma and sensory characteristics of Circassian cheese. Seven Circassian cheeses were provided by local producers. Aroma compounds were extracted by using solid-phase microextraction procedure and determined by gas chromatography-olfactometry system. Water-soluble, trichloroacetic acid-soluble and phosphotungstic acid-soluble nitrogen fractions ranged between 2.30-29.35%, 2.48-9.96% and 3.33-6.26%, respectively. Diacetyl, butyric acid, 2-acetyl-1-pyrroline, 1-octen-3-one and methional were identified at high intensities in cheeses. In addition, 'cooked', 'whey', 'creamy' and 'fermented' were defined as characteristic flavour terms for Circassian cheeses.
Biosynthesis of eight-carbon volatiles from tomato and pepper pomaces by fungi: Trichoderma atroviride and Aspergillus sojae
(Soc Bioscience Bioengineering Japan, 2017) Güneşer, Onur; Karagül Yüceer, Yonca
The aim of this study was to investigate the possibility of using tomato and red pepper pomaces for the production eight-carbon volatiles by Trichoderma atroviride and Aspergillus sojae. The fermentation of tomato and pepper pomace based media by both moulds was conducted in shake flasks and bioreactors. Microbial growth behaviours and fermentation abilities of T. atroviride and A. sojae under both fermentation conditions were followed by microbial counting. The production of flavours from tomato and pepper pomaces by fungal metabolism was determined by gas chromatography olfactometry, gas chromatography-mass spectrometry and sensory analysis. The results showed that T. atroviride grew faster than A. sojae, and the survival of T. atroviride in the tomato pomace was longer than that of A. sojae. However, T. atroviride grew slower than A. sojae in the pepper pomace. Eight-carbon flavour compounds, including (Z)-1,5-octadien-3-ol, 1-octen-3-ol, (E)-2-octenal and (E)-2-octenol, were produced by T. atroviride and A. sojae from the tomato and pepper pomaces. The highest production levels (265.55 +/- 2.79 and 187.47 +/- 0.92 mu g kg(-1)) were observed for 1-octen-3-ol in the tomato fermentation by T. atroviride and A. sojae, respectively. The relationships between volatile compounds and their flavour characteristics in tomato and pepper pomaces were analysed using principal component analysis. (C) 2017, The Society for Biotechnology, Japan. All rights reserved.
Physicochemical, textural, volatile, and sensory profiles of traditional Sepet cheese
(Elsevier Science Inc, 2011) Ercan, D.; Korel, F.; Karagül Yüceer, Yonca; Kınık, O.
Characterization of traditional cheeses is important for the protection of diversity of tradition and contributing baseline data for further research and quality control. Sepet cheese is a traditional cheese and specific to the Aegean region of Turkey. In this study, 52 Sepet cheese samples were analyzed to characterize the physicochemical, textural, volatile compounds, and sensory profiles. The changes in the physicochemical and volatile compositions were investigated during production and ripening periods. The average dry matter (DM; 55.16%), fat-in-DM (45.80%), protein (29.18%), salt-in-DM (12.88%), water activity (0.83), pH (5.50), titratable acidity (1.69%), ripening and lipolysis indices (11.06 and 6.36), firmness (212.20 N), springiness (0.62), cohesiveness (0.57), adhesiveness (0.48 Nmm), and chewiness (66.87 N) values of Sepet cheese samples were determined. Hexanoic, octanoic, decanoic, and butyric acids, which were responsible for the cheesy, waxy, goaty odors, were the most abundant volatile compounds in these cheeses. Most of the volatile compounds increased significantly during production and ripening. Significant changes in most of the physicochemical characteristics were observed up to the third month of ripening. As a result of the descriptive sensory analysis, Sepet cheeses were described with descriptors such as free fatty acid, animal like, sulfurous, creamy, cooked, and whey, and aromatics with high salty basic taste.
Bioflavour production from tomato and pepper pomaces by Kluyveromyces marxianus and Debaryomyces hansenii
(Springer, 2015) Güneşer, Onur; Demirkol, Aslı; Karagül Yüceer, Yonca; Özmen Togay, Sine; İşleten Hoşoğlu, Müge; Elibol, Murat
Bioflavours are called natural flavour and/or fragrance compounds which are produced using metabolic pathway of the microorganism and/or plant cells or their enzyme systems with bioengineering approaches. The aim of this study was to investigate bioflavour production from tomato and red pepper pomaces by Kluyveromyces marxianus and Debaryomyces hansenii. Obtained specific growth rates of K. marxianus and D. hansenii in tomato pomace were 0.081/h and 0.177/h, respectively. The bioflavour profile differed between the yeasts. Both yeasts can produce esters and alcohols such as phenyl ethyl alcohol, isoamyl alcohol, isoamyl acetate, phenyl ethyl acetate and isovaleric acid. Tarhana and rose were descriptive flavour terms for tomato and pepper pomaces fermented by K. marxianus, respectively. Tomato pomace fermented by D. hansenii had the most intense green bean flavour while fermented vegetable and storage/yeast were defined as characteristic flavour terms for pepper pomaces fermented by D. hansenii.
Chemical composition, antimicrobial, antioxidant and anthocyanin activities of mosses (Cinclidotus fontinaloides (Hedw.) P.Beauv. and Palustriella commutata (Hedw.) Ochyra) gathered from Turkey
(Taylor & Francis Ltd, 2017) Tonguç Yayıntaş, Özlem; Alpaslan, Duygu; Karagül Yüceer, Yonca; Yılmaz, Selehattin; Şahiner, Nurettin
Cinclidotus fontinaloides (Hedw.) P. Beauv. and Palustriella commutata (Hedw.) Ochyra were used in this study. The chemical composition of mosses in the ethanol and water extract was determined using GC-MS and FT-IR. Antioxidant activities of moss extracts were tested by total phenol and ABTS methods. Trolox equivalent value (TEAC) of mosses was calculated as 26 +/- 0.32 and 10 +/- 0.22 mg/g. The amounts of the flavonoid compounds were calculated as mg gallic acid. Gallic acid equivalent value of mosses was calculated as 587 +/- 0.55 and 496 +/- 0.22 mg/g. The extracts antimicrobial activity was tested against Escherichia coli (ATCC 8739), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 10145) and Candida albicans (ATCC 10231). Significant antibacterial effect was observed for C. fontinaloides and P. commutata in ethanol extract. Total anthocyanin activities of C. fontinaloides and P. commutata were determined as 50 +/- 0.17 and 144 +/- 0.33 mg/L.

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