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Öğe A comparative study of amino acid, mineral and vitamin profiles of milk from Turkish Saanen, Hair and Maltese goat breeds throughout lactation(Wiley, 2021) Günay, Emine; Güneşer, Onur; Karagül Yüceer, YoncaThis study aimed to evaluate the changes in nutritional compounds such as amino acids, minerals, and vitamins in the milk of Turkish Saanen, Hair and Maltese goat breeds. The Turkish Saanen goat breed had lower dry matter, fat, nitrogen, and vitamins A, E and B-2 than Maltese and Hair goat breeds throughout lactation period. High levels of proline, leucine, glutamic acid, and glutamine were found in all breeds. Except for tyrosine, all other amino acids were higher in Hair goat milk than those in other breed milk. The calcium content of the samples ranged from 1164.79 to 1214.16 mg/L.Öğe Aromatic and Sensorial Properties of Çökelek Cheese Produced by Different Methods(2019) Gün, İlhan; Güneşer, Onur; Karagül Yüceer, Yonca; Güzel Seydim, Zeynep Banu; Torun, Fatma; Çakıcı, SevdaN this study, it was aimed to reveal aroma-active compounds andensory properties of Çökelek cheese made from milk, yogurt and Tuluk yogurt. For this purpose, aroma active compounds in Çökelek samples were determinedby Gas Chromatography-Olfactometry. Furthermore, sensory properties of cheesesamples were determined by Spectrum® analysis. As result, 17 identified and 2unknown aroma active compounds were determined in Çökelek samples. Butyricacid, Furaneol® and sotolon were identified at high intensities in all cheeses. Itwas determined that the intensity of butyric acid was higher in Çökelek made fromyogurt while the intensities of Furaneol® and sotolon were found to be higher inÇökelek made from milk. “Cooked”, “Whey”, “Creamy”, “Rancid” “Fermented”,“Yeast”, “Sour”, “Salty”, “Sweet” and “Umami” were defined as characteristicsensory terms for Çökelek cheeses. It was determined that cooked, creamy andsweet were perceived in Çökelek made from yogurt while yeast aroma was foundto be a higher in Çökelek made from Tuluk yogurt.Öğe Assessment of Quality and Aroma Characteristics of Kefir Produced by Using Grain and Lyophilized Culture(2021) Şen, İrem; Güneşer, Buket Aydeniz; Güneşer, OnurKefir is traditionally produced using kefir grains, while lyophilized culture is widely used in industry. Microbial fermentation of kefir has critical importance on its aromatic profile and sensory attributes as well as its physicochemical parameters. The main objective of this study was to compare the differences between some physical, chemical, microbiological, sensory attributes and volatile components in kefir fermented with kefir grains and lyophilized cultures during storage. The compositional characteristic of kefir cultured by both kefir grains and lyophilized starter were monitored during 21-day storage in this study. In contrast to dramatic decreases in titratable acidity, serum separation and Streptococcus spp. count, an increase in the amount of various aroma compounds including 2- heptanone, butyric acid, hexanoic acid and octanoic acid was observed during storage of kefir samples. Incubation with lyophilized starter culture promoted kefir’ sensory and rheological attributes besides of improving its diacetyl and acetic acid aroma intensities compared with that incubation with kefir grain. “Sour”, “sweet”, “salty” and “bite (CO2)” were developed as taste terms, while “cooked” “creamy”, “fermented”, “dairy” and “yeast” were some aromatic terms for kefir samples developed by sensory evaluation. Consumer acceptance scores of the kefirs produced by using lyophilized cultures were higher than samples with grain.Öğe Besin Piramidleri(Sidas Medya A.Ş., 2005) Caner, Cengiz; Kaynak, Kayhan; Güneşer, OnurThe Food Guide Pyramid FGP was designed as an easy way to show the groups of foods that make up a healthy diet. It also tells you that you should eat a variety of foods from all five groups and how much of the foods from the different groups you should eat to stay healthy. The Pyramid emphesis for eating a variety of foods to get the energy, protein, vitamins, minerals, and fiber you need for good health.In this review, food pyramid which has been created by USDA was explained and also the various of a 'New Design Food Pyramind' was eplained and compared with the old pyramidÖğe 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, MuratBioflavours 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.Öğe 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, YoncaThe 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.Öğe Characterisation of aroma-active compounds, chemical and sensory properties of acid-coagulated cheese: Circassian cheese(Wiley, 2011) Güneşer, Onur; Karagül Yüceer, YoncaThe 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.Öğe 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, MehmetEzine 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.Öğe Consumer Expectation and Preference of Ezine Cheese(Univ Namik Kemal, 2013) Delice, N. Y.; Güneşer, Onur; Karagül Yüceer, YoncaThe objective of this study was to determine the preferences and purchasing behaviors of consumers of Ezine cheese. Consumer acceptance tests on two representative Ezine cheeses and face to face interviews were conducted in Canakkale-Turkey. Data provided from both tests were evaluated by Analysis of Variance and K-Means Cluster Analysis. Our data showed that Ezine cheese is mainly preferred for breakfast. Most consumers purchased Ezine cheese at least once a week. Our data detected a positive relationship between consumer age and acceptance of Ezine cheese. The age group 60-69 years old most preferred both cheeses. Statistical analysis clustered the Ezine cheese consumers into four groups, and significant differences were observed among the clusters with regards to consumption and purchasing behaviors. Cheese flavor and overall liking appear to be the most important factors for consumption. Asa result, habits of cheese consumption, benefits of dairy products, and enhancement of breakfast choices influenced consumer decisions for purchasing Ezine cheese.Öğe Different Bioengineering Approaches on Production of Bioflavor Compounds(Elsevier, 2018) İşleten Hoşoğlu, Müge; Güneşer, Onur; Karagül Yüceer, YoncaFlavor compounds are generally used as food additives and mostly produced through artificial means-that is, chemical synthesis or by extraction from plant and animal sources. The increasing consumer preference for natural products has promoted significant efforts toward the biotechnological production of these compounds (bioflavor). There are two kinds of aroma and flavor production via biotechnological process, de novo microbial processes and bioconversions of natural precursors using microbial cells or enzymes. The production of bioflavors with microorganisms and enzymes is illustrated by the discussion of the current state of the art developments in this field. Efforts at production of flavor compounds often lack economic profitability, mainly due to low productivities or low concentrations of target compounds in fermentation broth. This chapter reviews also the current state of the art of bioprocess used for the production of flavor and fragrance compounds, with emphasis on different ways used to improve process productivity. Bioengineering provides promising technical options for increasing the productivity with bioflavor production, such as different fermentation strategies (batch, fed-batch, and continuous fermentation), gas-phase or two-phase reactions, specific reactor constructions such as membrane, solid-state or closed loop reactors, optimization and modeling approaches of bioprocess and in situ recovery of product. © 2018 Elsevier Inc. All rights reserved.Öğe Effect of ultraviolet light on water- and fat-soluble vitamins in cow and goat milk(Elsevier Science Inc, 2012) Güneşer, Onur; Karagül Yüceer, YoncaThe objective of this study was to investigate and compare the effects of UV light and heat treatment on vitamins A, B-2, C, and E in cow and goat milk. Vitamins were analyzed by reverse-phase high-pressure liquid chromatography. Ultraviolet and pasteurization treatments caused loss in vitamin C in milk. Pasteurization did not have any significant effect on vitamin B-2. However, UV light treatment decreased the amount of vitamin B2 after several passes of milk through the UV system. In addition, UV light treatment decreased the amount of vitamins A and E. Vitamins C and E are more sensitive to UV light. UV light sensitivities of vitamins were C > E > A > B-2. These results show that UV light treatment decreases the vitamin content in milk. Also, the number of passes through the UV system and the initial amount of vitamins in milk are important factors affecting vitamin levels.Öğe ENGINEERING OF MILK-BASED BEVERAGES: CURRENT STATUS, DEVELOPMENTS, AND CONSUMER TRENDS(Woodhead Publ Ltd, 2019) Güneşer, Onur; İşleten Hoşoğlu, Müge; Aydeniz Güneşer, Buket; Karagül Yüceer, Yonca[Anstract Not Available]Öğe Evaluation of physicochemical, microbiological, sensory properties and aroma profiles of goat cheeses provided from Canakkale(Wiley, 2017) Özmen Togay, Sine; Güneşer, Onur; Karagül Yüceer, YoncaThe purpose of this study was to determine physicochemical and sensory properties, aroma-active compounds and number of lactic acid bacteria in goat cheeses. High variation was observed among the cheeses in terms of fat %(w/w) and salt %(w/w) contents and titratable acidities %(w/w). Average counts of lactococci lactobacilli and enterococci were 6.90, 6.43 and 5.26log cfu (colony-forming unit)/g, respectively. The following compounds had high aroma intensity in the cheeses: acetic acid, butanoic acid, hexanoic acid, p-cresol and phenyl acetic acid. Cooked, whey, creamy, animal-like, waxy, salty and sour were the characteristic sensory descriptors.Öğe Evaluation of some physical, chemical and sensory properties of kasar cheese and its processed and analogue types(Ankara University, 2017) Yalman, Musa; Güneşer, Onur; Karagül Yüceer, YoncaThe objective of this study was to evaluate the changes in physical, chemical and sensory properties of the kasar cheese and its processed and analogue types during 90-day storage. Aroma-active compounds in the cheeses were identified by gas chromatography-olfactometry. Sensory properties of the cheeses were determined by descriptive sensory analysis. Differences in basic composition of the cheeses were found. There were also significant differences among the cheeses in terms of meltability, oil separation index, L* and a* values. Whey, cooked, creamy and fermented were the most intense sensory descriptors in the cheeses analyzed on days 1 and 30. However, waxy and animal intensities were much higher in analogue cheese than others. 18 aroma-active compounds were determined in the cheeses during 90 day storage. Diacetyl, acetic acid, butyric acid, 2-/3-methyl butyric acid, 2-acetyl-2-thiazoline, ?-ionene, 2-phenylethyl alcohol, maltol, p-cresol, sotolon, ?-decalactone and ?-dodecalactone were some of the characteristic aroma-active compounds. Kasar cheese was the most liked cheese while analogue cheese was the least liked cheese by consumers. © Ankara Üniversitesi Ziraat Fakültesi.Öğe Evaluation of Some Physical, Chemical and Sensory Properties of Kasar Cheese and Its Processed and Analogue Types(Galenos Publ House, 2017) Yalman, Musa; Güneşer, Onur; Karagül Yüceer, YoncaThe objective of this study was to evaluate the changes in physical, chemical and sensory properties of the kasar cheese and its processed and analogue types during 90-day storage. Aroma-active compounds in the cheeses were identified by gas chromatography-olfactometry. Sensory properties of the cheeses were determined by descriptive sensory analysis. Differences in basic composition of the cheeses were found. There were also significant differences among the cheeses in terms of meltability, oil separation index, L* and a* values. Whey, cooked, creamy and fermented were the most intense sensory descriptors in the cheeses analyzed on days 1 and 30. However, waxy and animal intensities were much higher in analogue cheese than others. 18 aroma-active compounds were determined in the cheeses during 90 day storage. Diacetyl, acetic acid, butyric acid, 2-/3-methyl butyric acid, 2-acetyl-2-thiazoline, beta-ionene, 2-phenylethyl alcohol, maltol, p-cresol, sotolon, delta-decalactone and gamma-dodecalactone were some of the characteristic aroma-active compounds. Kasar cheese was the most liked cheese while analogue cheese was the least liked cheese by consumers.Öğe Ezine peyniri II. olgunlaşma süresince proteoliz düzeyi(2010) Tunçel, N. Barış; Güneşer, Onur; Engin, Burcu; Yaşar, Kurban; Zorba, N. Nükhet; Karagül Yüceer, YoncaBu çalışmada, Ezine peynirinin olgunlaşma süresi boyunca proteoliz düzeyindeki değişim incelenmiştir. Bir yıllık olgunlaşma periyodu boyunca suda çözünür azot, %12’lik trikloroasetik asitte çözünen azot ve %5’lik fosfotungustik asitte çözünen azot oranları belirlenmiş ve peynirin elektroforetik analizi gerçekleştirilmiştir. Olgunlaşma süresince, Ezine peynirinin toplam azot içeriği değişmezken, azot fraksiyonlarının oranı önemli düzeyde artmıştır. Elektroforetik analiz sonuçları depolama süresince b-kazein fraksiyonundaki parçalanmanın ?s-kazeininkinden daha yavaş olduğunu göstermiştir.Öğe Farklı katkı maddeleri kullanımının tahin helvası emulsiyon stabilitesi ve kalitesine olan etkilerinin belirlenmesi üzerine bir çalışma(Çanakkale Onsekiz Mart Üniversitesi, 2009) Güneşer, Onur; Zorba, MuratBu çalışmada Türk Gıda Kodeksi tahin helvası tebliğinde emulgatör olarak kullanımına izin verilen katkı maddelerinin tahin helvasına eklenerek, helvada görülen yağ salma probleminin çözülmesi amaçlanmıştır. Bu amaçla; sorbitan tristearat (STS, 3,5 g/kg), sorbitan monopalmitat (SMP, 3,5 g/kg) ve sorbitan tristearat: sorbitan monopalmitat (1:1) karışımı (K2, 2 g/kg) eklenerek üretilmiş helvalar, üç farklı sıcaklıkta (20, 30 ve 40 ? C) depolanmış ve katkı maddesi çeşidi, depolama sıcaklığı ve depolama süresinin helvaların fiziksel, kimyasal ve duyusal kalitesi üzerine olan etkileri incelenmiştir. Söz konusu faktörlerin helvaların fiziksel, kimyasal ve duyusal özelliklere etkisi Tekrarlanan Ölçümlü Deneme Düzeninde Varyans Analizi Tekniği ve Friedman testi kullanılarak araştırılmıştır.Katkı maddelerinin kullanımının, helvaların yağ miktarı hariç diğer fiziksel, kimyasal ve duyusal özelliklerine etkisi görülmezken, depolama süresi ve sıcaklığının ise söz konusu özellikler üzerine etkilerinin olduğu saptanmıştır. Helvaların dokusal delme kuvvetinin, depolama süresi ve sıcaklığın artmasıyla arttığı gözlenmiştir. Tüm depolama sıcaklıklarında depolama boyunca helvaların L* renk değerinde önemli bir değişim gözlenmezken, -a renk değerlerinde 20 ? C ve 30 ? C' sıcaklıkta bir azalma, 40 ? C'de sıcaklıkta ise bir artma olmuştur. Üretilen tüm helva örneklerinin nem miktarındaki değişimin depolama boyunca 20 ? C'de daha fazla olduğu saptanmıştır. Tüm depolama sıcaklıklarında helvaların protein, kül ve toplam şeker miktarlarında depolama süresince istatistiksel açıdan önemli bir değişim gözlenmemiştir. K2 karışımının helvalarda yağ salmanın engellenmesinde, söz konusu katkı maddelerinin tek tek kullanılmalarına göre daha olumlu etki gösterdiği görülmüştür. Helvaların görünüş, doku ve lezzet özelliklerine ait puan ortalamaları depolama süresince düşüş göstermiştir. Doku özelliğine ait puan ortalamalarındaki düşüşler 20°C ve 40oC'de depolanan örneklerde 12. günden sonra, 30oC'de depolanan örneklerde ise 36. günden sonra önemli olmuştur. Helvaların lezzet özelliğine ait puan ortalamaları ait düşüşlerin ise depolamanın 12. günden itibaren önemli olduğu görülmüştür.Anahtar Kelimler: Tahin Helvası, Emülsiyon Stabilitesi, Emülgatör, Sorbitol EsterleriÖğe Growth and by-product profiles of Kluyveromyces marxianus cells immobilized in foamed alginate(Wiley, 2015) Wilkowska, Agnieszka; Kregiel, Dorota; Güneşer, Onur; Karagül Yüceer, YoncaThe aim of this research was to study how the yeast cell immobilization technique influences the growth and fermentation profiles of Kluyveromyces marxianus cultivated on apple/chokeberry and apple/cranberry pomaces. Encapsulation of the cells was performed by droplet formation from a foamed alginate solution. The growth and metabolic profiles were evaluated for both free and immobilized cells. Culture media with fruit waste produced good growth of free as well as immobilized yeast cells. The fermentation profiles of K. marxianus were different with each waste material. The most varied aroma profiles were noted for immobilized yeast cultivated on apple/chokeberry pomace. Copyright (c) 2014 John Wiley & Sons, Ltd.Öğe Gıdalarda aroma maddelerinin belirlenmesinde Gaz kromatografisi-olfaktometri (GCO) tekniklerinin kullanılması(2010) Güneşer, Onur; Karagül Yüceer, YoncaEnstrümantal ve duyusal analiz tekniklerinin bir kombinasyonu olan Gaz kromatografisi-olfaktometri (GCO) tekniği Fuller ve arkadaşları tarafından 1964 yılında geliştirilmiştir. Bu teknik süt, peynir, et, meyve, sebze, meyve suyu ve şarap gibi birçok gıda ürününde bulunan aroma aktif bileşenlerin tanımlanması ve bu bileşenlerin gıdanın tüm aroması üzerine etkilerinin ortaya konması amacıyla yaygın olarak kullanılmaktadır. GCO'da verilerin toplanması, işlenmesi ve gıdalarda bulunan her bir aroma aktif bileşenin duyusal katkısını saptamak için birçok GCÖ metodu geliştirilmiştir. Bu çalışmada; gıdalardaki aroma maddelerinin belirlenmesinde kullanılan GCO metotları hakkında genel bilgiler verilmiş ve bazı gıdalarda bu metotlarla ilgili çalışmalar değerlendirilmiştir.Öğe İNEK VE KEÇİ SÜTÜ KULLANILARAK ÜRETİLEN PROBİYOTİK FERMENTE SÜT ÜRÜNLERİNİN KARAKTERİSTİK ÖZELLİKLERİ(2020) Nalbant, Duygu; Güneşer, OnurÇalışmada, inek ve keçi sütünün L. acidophilus, Bifidobacterium animalis subsp. lactis ve S.thermophilus karışıkkültürü (ABT), Bifidobacterium animalis subsp. lactis (BB) ve L.acidophilus (LA) kültürleriyle fermente edilmesiyleelde edilen probiyotik süt ürünlerinin 4°C’de 30 gün depolanması süresince fizikokimyasal ve duyusalözelliklerinin belirlenmesi amaçlanmıştır. Laktoferrin değerinin süt örneklerinde probiyotik fermenteürünlere göre daha yüksek olduğu görülmüştür. ACE inhibitör aktivitesi ölçümü sonuçlarının, keçi sütü ileüretilen probiyotik fermente ürünlerde inek sütü ile üretilenlere göre daha düşük olduğu tespit edilmiştir.Pişmiş, kremamsı, fermente, sütümsü, yavan, ekşi, tatlı, tuzlu ve buruk tüm ürünlerde tespit edilen duyusaltanımlayıcılardır. Ancak hayvansı koku yalnızca keçi sütü ile üretilen ürünlerde tespit edilmiştir. Tümprobiyotik fermente ürünlerde bütirik asit, asetik asit, asetoin, diasetil, d-limonen, hekzanoik asit ve 2-nonanon uçucu bileşenleri tespit edilmiştir.
