Prof. Dr. A. Kadir HALKMAN Yönetim Kurulu Baflkan / President of the Association. Danışma Kurulu / Advisory Board

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1 GIDA (G da Teknolojisi Derne i Yay n ) THE JOURNAL OF FOOD (Published by the Association of Food Technology; Turkey) Cilt / Volume: 39 Say / Number: ki ayda bir yay mlan r / Published bimonthly ISSN ; ISSN (GIDA on-line) Sahibi / Owner G da Teknolojisi Derne i Ad na / On behalf of the Association of Food Technology; Turkey Prof. Dr. A. Kadir HALKMAN Yönetim Kurulu Baflkan / President of the Association Editörler Kurulu / Editorial Board Baş Editör/ Editor-in Chief Halkman, A. Kadir Ankara University, Turkey Editörler / Co-Editors Çak r, brahim Abant zzet Baysal University, Turkey Taban, Birce Ankara University, Turkey Tekin, Aziz Ankara University, Turkey Velio lu, Y. Sedat Ankara University, Turkey Yönetim Yeri Adres / Address Büyükelçi Sokak No: 18/1 Kavakl dere/ Ankara Turkey Tel: (+90) Faks: (+90) E-posta / dergi@gidadernegi.org URL: Yayın Türü: Yayg n süreli ve hakemli Basım Yeri / Printing House Sim Matbaac l k Ltd. fiti G.M.K. Bulvar 108/1 Maltepe / Ankara Turkey Tel : (+90) Faks: (+90) simmatbaasi@gmail.com Yayın Tarihi / Publication Date Danışma Kurulu / Advisory Board Alichanidis, Efstathios Aristotle University of Thessaloniki, Greece Aran, Necla Istanbul Technical University, Turkey Art k, Nevzat Ankara University, Turkey Baysal, Taner Ege University, Turkey Boyac, smail Hakk Hacettepe University, Turkey Certel, Muharrem Akdeniz University, Turkey Draughon, Ann Tennessee University, USA Ekfli, Aziz Ankara University, Turkey El Soda, Morsi University of Alexandria, Egypt Fogliano,Vincenzo University of Napoli Federico II, Italy Ghosh, Bikash C. National Dairy Research Institute, India Gollop, Natan The Volcani Center, ARO, Israel Gökmen, Vural Hacettepe University, Turkey Griffiths, Mansel University of Guelph, Canada Gö üfl, Fahrettin Gaziantep University, Turkey Gümüflkesen, Aytaç Sayg n Ege University, Turkey Güven, Mehmet Cukurova University, Turkey Heperkan, Dilek Istanbul Technical University, Turkey Ho, Chi-Tang The State University of New Jersey, USA Kaya, Mükerrem Atatürk University, Turkey Kaymak-Ertekin, Figen Ege University, Turkey Koçak, Celalettin Ankara University, Turkey Köksel, Hamit Hacettepe University, Turkey Morales, Francisco J. CSIC Instituto del Frío, Spain Mujtaba, Mustafa G. Florida Gulf Coast University, USA Ögel, Zümrüt Middle East Technical University, Turkey Özilgen, Mustafa Yeditepe University, Turkey Paalme, Toomas Tallinn University of Technology, Estonia Parlar, Harun Technical University of Munich, Germany Raspor, Peter University of Ljubljana, Slovenia Rezessy-Szabo, Judit M. Corvinus Universty of Budapest, Hungary fiahin, Serpil Middle East Technical University, Turkey Üstünol, Zeynep Michigan State University, USA Yetiflemiyen, Atila Ankara University, Turkey Bu dergi, uluslararas CAB Abstracts, Citefactor, Index Copernicus, EBSCO ve ULAKBİM (Tar m, Veteriner ve Biyoloji Bilimleri) ve DOAJ veri tabanlar kapsam ndad r. This journal is covered by CAB Abstracts, Citefactor, Index Copernicus, EBSCO and ULAKBİM (National Agriculture, Veterinary and Biology) and DOAJ database systems. i

2 İçindekiler / Content Temiz H, Tarakç Z, Islam A; Effect of Cherry Laurel Marmalade on Physicochemical and Sensorial Characteristics of the Stirred Yogurt During Storage Time / Depolama Süresince P ht s K r lm fl Yo urtlar n Fizikokimyasal ve Duyusal Özellikleri Üzerine Karayemifl Marmelad n n Etkisi Turhan, Öner Z; Determination of Starter Culture Properties of Lactic Acid Bacteria Isolated From Cheese / Peynirden zole Edilen Laktik Asit Bakterilerinin Starter Kültür Özelliklerinin Belirlenmesi Altunkaya A, Y ld r m B, Ekici K, Terzio lu Ö; Determining Essential Oil Composition, Antibacterial and Antioxidant Activity of Water Wormwood Extracts / Pelin Otu Ekstraktlar n n Temel Uçucu Ya Kompozisyonunun, Antibakteriyel ve Antioksidan Aktivitesinin Belirlenmesi Uçan F, A çam E, Aky ld z A; Do al Bulan k Limon Suyu Üretimi Üzerine Bir Araflt rma / A Research on Production of the Natural Cloudy Lemon Juice Köten M, Ünsal S, Atl A; Türkiye de Üretilen Makarnalar n Baz Kimyasal Bileflimlerinin ve Piflme Kalitelerinin Belirlenmesi / Determination of Cooking Quality and some of the Chemical Compositions of Pasta Which Produced in Turkey Kanmaz EÖ, Ova G; Kritik Alt Su Ekstraksiyonu flleminin G da Endüstrisinde Kullan m na Yönelik Uygulamalar / The Applications of Subcritical Water Extraction for the Food Industry Kanmaz EÖ, Ova G; Filizlenme flleminin Fitokimyasal Bileflikler Üzerine Etkisi / The Effect of Sprouting Process on Phytochemical Compounds Day soylu KS, Gezginç Y, Cingöz A; Fonksiyonel G da m, Fonksiyonel Bileflen mi? G dalarda Fonksiyonellik / Functional Food or Functional Component? Functionality in Foods ii

3 Editörden, Merhaba, 2014 y l 39. cilt ilk say s nda 3 ngilizce ve 2 Türkçe araflt rma ile birlikte 3 derleme makalesi var. Bu say n n bask tarihi 15 fiubat 2014 olmas na karfl n, bu makaleler elektronik ortamda Ocak ay sonuna kalmadan yay mland. Ayn tarihte tüm ifllemleri bitmifl ve dolay s yla bask ya haz r halde bekleyen 10 makale daha vard. Bu makalelere dergi cilt numaras verdik ancak say ve sayfa numaras veremiyoruz. Bunun nedeni yay n politikam zd r. Yay nlarda bas m önceli imiz ngilizce araflt rma, Türkçe araflt rma ve derleme fleklindedir. Dergimizde her makalenin gelifl tarihi, yazar taraf ndan düzeltilerek gelifl tarihi ve kabul tarihi görülmektedir. Baz makaleler gönderildi i flekli ile hakemlerimiz taraf ndan kabul ediliyor. Ya da makalelerde önemsiz flekil hatalar oldu unda, düzeltilerek gelifl tarihini göstermiyoruz. Çok genel olarak söylemek gerekirse, makale ifllemleri ortalama olarak 3-4 ay içinde tamamlan yor. Baz makalelerde, biz de rahats zl k duydu umuz halde, bu süre çok uzayabiliyor. Ancak 2014 Ocak ay içinde gelen bir makale aç k söylemek gerekirse bizi çok flafl rtt. 13 Ocak 2014 tarihinde gelen makaleyi 14 Ocak 2014 tarihinde hakemlere gönderdik ve her 2 hakem de 3 gün içinde de erlendirme raporlar n gönderdiler. Her 2 rapor da makalenin gönderildi i flekli ile kabul edildi i yönünde idi. 17 Ocak 2014 tarihinde yazara makalesinin gönderildi i flekli ile kabul edildi ini bildirdik. Makalenin matbaada dizilmesi, yazara kontrol için gönderilmesi, yazar n kontrolü ve varsa düzeltmelerden sonra elektronik ortamda yay mlanmas ocak sonunu geçmez. Bu örnekte, makalenin bilimsel içeri i yan nda GIDA Dergisi yaz m kurallar na tam uyum ile gönderilmifl olmas da etkili oldu. Kabul edilen makaleleri dizgi öncesinde yazarlara word dosyas olarak gönderirken, makalelerini çok dikkatli bir flekilde okumalar n, varsa düzeltmelerini bu dosyada yapmalar n ve bize bu word dosyalar n n gönderilmesini istiyoruz. Dizgi sonras makaleleri bu kez pdf dosyas olarak gönderip, bask öncesi son kontrollerinin yap lmas n istiyoruz. Bu aflamada küçük düzeltmeler sorun olmuyor ancak bazen makalenin tümüyle yeniden dizilmesi de gerekiyor. Bu koflulda, kabul edilmifl bir makalenin elektronik ortamda yay mlanmas çok zaman alabiliyor. Önümüzde Kas m 2013 tarihlerinde Kufladas Pine Bay Otelde yapaca m z 2. Uluslararas G da Teknolojisi Kongresi oldu unu ve adresinde kay tlar n bafllad n tekrar hat rlatmak isterim. Sevgi ve sayg lar mla, Prof. Dr. A. Kadir Halkman iii

4 A Message from the Editor-in-Chief Hello, In addition to 3 research articles in English and 2 research articles in Turkish, there are 3 review articles in the first issue of volume 39 of the year Although the publishing date of this issue is February 15, 2014, these articles were printed in electronic form before the end of January. There are 10 articles of which all processing had been completed and so had been waiting for publishing at the same time. We gave journal volume numbers to these articles but we cannot give issue and page numbers. The reason of this is our publishing policy. Our priority in publishing is research articles in English, research articles in Turkish and review articles. The received date, received in revised form date and the accepted date of each article is seen in our journal. Some articles have been accepted as in their first received form by our reviewers. Or, we do not show the received in revised form date when there are minor errors in the articles. Very generally speaking, the processing of an article is completed within 3-4 months on average. This period, although we also feel uncomfortable, can take longer for some articles. However, an article send in January 2014 was frankly surprised us. We sent the article which was received on January 13, 2014 to the reviewers on January 14, 2014 and both of the reviewers sent their evaluation reports in 3 days. Both of these reports were in the way that "the article is accepted as in received form". We informed the author that his/her article had been accepted as in received form on January 17, The printing of it in electronic form after its type-setting, sending it to the author for final control, the final control of the author and the corrections (if any) does not exceed the end of January. In this example, the submission of the article with full compliance with the rules of the Food Journal became effective in addition to the scientific content of the article. While sending the accepted articles to the authors as word files before type-setting, we want them to read their articles very carefully, to make corrections (if any) on these files and to send them back to us. After the type-setting, we send the articles to the authors this time as pdf files and want their final controls before publishing. At this stage, little corrections are not a problem, but sometimes the article needs to be retyped completely. In this condition, the printing of the accepted article in electronic form takes up more time. I would like to remind you once again that there will be the 2 nd International Congress on Food Technology at Pine Bay Hotel in Kufladas on November, 2013 and the registration has been started at Best Regards, Prof. A. Kadir Halkman iv

5 GIDA (2014) 39 (1): 1-8 doi: /gida GD Research / Araflt rma EFFECT of CHERRY LAUREL MARMALADE on PHYSICOCHEMICAL and SENSORIAL CHARACTERISTICS of THE STIRRED YOGURT DURING STORAGE TIME Hasan Temiz 1 *, Zekai Tarakçı 2, Ali Islam 3 1 Department of Food Engineering, Faculty of Engineering, Ondokuz Mayis University, Samsun, Turkey 2 Department of Food Engineering, Faculty of Agriculture, Ordu University, Ordu, Turkey 3 Department of Horticulture, Faculty of Agriculture, Ordu University, Ordu, Turkey Received / Gelifl tarihi: Received in revised form / Düzeltilerek Gelifl Tarihi: Accepted / Kabul tarihi: Abstract The objective of this study was to investigate the effect of Cherry laurel marmalade (0%, 5%, 10%, 15%, and 20%) on the physico-chemical and sensorial characteristics of yogurts during the storage time. Increasing marmalade concentrations into the yogurts affected titratable acidity, a* values and overall acceptability positively, and viscosity, syneresis and L* values negatively. During storage time ph, viscosity, syneresis, b* values, flavour and overall acceptability scores (P<0.05) decreased significantly compared to control, while titratable acidity and a* values (P<0.05) increased significantly. When compared to L* values at the end of storage time with the first day L* values, at the marmalade added samples were observed an increasing but, at the control samples a decreasing were observed. 15% cherry laurel marmalade would be recommended in the production of fruit yogurts. Keywords: Yogurt, cherry laurel, syneresis, viscosity, color, sensorial properties. DEPOLAMA SÜRESİNCE PIHTISI KIRILMIŞ YOĞURTLARIN FİZİKOKİMYASAL VE DUYUSAL ÖZELLİKLERİ ÜZERİNE KARAYEMİŞ MARMELADININ ETKİSİ Özet Bu çal flman n amac, depolama süresince yo urtlar n fizikokimyasal ve duyusal özellikleri üzerine karayemifl marmelad n n (%0, %5, %10, %15 ve %20) etkisini incelemektir. Yo urtlara ilave edilen marmelat konsantrasyonunun art r lmas titrasyon asitli ini, a* de erini ve genel kabul edilebilirlili i pozitif olarak, viskozite, su salma, L* de erlerini ise negatif olarak etkilemifltir. Depolama süresince ph, viskozite, su salma, L* ve b* de erleri tat ve genel kabul edilebilirlilik puanlar kontrolle karfl laflt r ld nda önemli düzeyde azal rken (P<0.05) titrasyon asitli i ve a* de eri önemli düzeyde artm flt r (P<0.05). Depolaman n 1. günündeki L* de erleri depolama sonundaki L* de erleriyle karfl laflt r ld nda, marmelat ilaveli örneklerde bir azalma gözlemlenmifl fakat konrol örneklerinde bir art fl belirlenmifltir. Meyveli yo urtlar n üretiminde %15 karayemifl marmelad tavsiye edilebilmektedir. Anahtar sözcükler: Yo urt, karayemifl, Su salma, Viskozite, Renk, Duyusal özellikler. *Yazışmalardan sorumlu yazar / Corresponding author; hasant@omu.edu.tr, (+90) /1508, (+90)

6 H. Temiz, Z. Tarakçı, A. Islam INTRODUCTION Cherry laurel (Laurocerasus officinalis) belongs to the Rosaceae family and is a popular fruit, mainly distributed in the coasts of the Black Sea region of Turkey and is locally called Karayemis (1). It is mostly consumed as fresh fruit in local markets although it may also be dried, pickled, and processed into pekmez, jam, marmalade, and fruit juice products (2). Besides its use for food, both fruit and seeds of cherry laurel are well known as traditional medicines in Turkey and have been used for many years for the treatment of stomach ulcers, digestive system complaints, bronchitis, eczemas, hemorrhoids, and as a diuretic agent, among others (3, 4). For years, food analysts and plant physiologists have been interested in the effects of maturation on the chemical components in the edible parts of fruits because of their impact in the market quality of the food product (5, 6). The plant-derived edible and non-edible products contain a wide range of phenolic compounds such as phenolic acids, flavonoids, anthocyanins, tannins, lignans, and catechin that possess antioxidant activities. These phenolics provide protection against harmful free-radicals, and have been known to reduce the risk of certain types of cancer, coronary heart disease, cardiovascular disease, stroke, atherosclerosis, and other degenerative diseases associated with oxidative stress (5, 7). Yogurt is a fermented dairy product obtained by lactic acid fermentation of milk, and is a popular product throughout the world (8-11). The origin of yogurt is not known definitely; but, historical records say that yogurt was firstly made by Turks in the Middle East (12). Fruit-flavored yogurts are produced by adding fruit concentrates or flavored syrups to the cultured milk after or before the incubation process. Fruit added yogurts are now widely consumed both by infant and adult populations (13). At the same time, fruit leads to an increase in the nutritional value and causes product variability in the markets (14, 15). The objective of this study was to develop a new type of stirred fruit-flavored yogurt by adding Cherry laurel marmalade and to determine the effect of the marmalade on the physicochemical and sensorial properties of the yogurts during storage time. MATERIALS and METHODS The Cherry laurel fruit was colleted from the coasts of the Black Sea Region of Turkey. Raw cow s milk used in the manufacture of yogurt obtained from the dairy farm in Ordu, Turkey. Commercial freeze-dried starter culture (Y-080 F, a blend of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) was provided by Sacco, Cadorago, Italy and was used in the production of yogurt. Production of Cherry Laurel Fruit Pulp Decayed and unripe fruits were separated then the rest of the fruits were washed. Seeds were removed manually and the pulp was homogenized with an Ultra Turrax homogenizer (Cat X120, Germany). 30% sugar was added to the pulp. The pulp was then pasteurized at 90 ± 1 C for 5 min and transferred to sterile glass jars. After cooling they were kept at ambient temperature until their use in the experimental yogurts. Manufacture of Experimental Yogurts The total solid of milk was adjusted 14% with nonfat milk powder (Pinar AS, Dairy Product Company, Pinarbasi, Izmir, Turkey) at 40 C. Then milk was pasteurized at 95 C for 10 min, cooled to 45 C, and divided into five equal parts (250 g sterile glass cups). Commercial freeze-dried yogurt starter culture was reactivated by inoculation in sterilized reconstituted milk and incubated at 44±1 C before being used in the yogurt production. Then, milk was inoculated with 2% (v/v) reactivated yogurt cultures, and incubated at 43±1 C until the ph reached 4.6 (approximately 3.5 h), and were stored for 24 h at 4 C. One batch of yogurt was then taken as control, and the remaining batches were prepared with one of the mixtures of 5%, 10%, 15% and 20% Cherry laurel marmalade, and samples were coded as CY, K1, K2, K3 and K4, respectively. All experimental yogurts were stored at 4 C for 21 days. Samples were analyzed for physicochemical and sensorial properties after 1, 7, 14 and 21 days of storage. Experiments were replicated twice. Analytical Methods The color of yogurt samples was measured using the CIELAB system with a colorimeter (Minolta CR 400, Japan), calibrated with a white tile (Minolta calibration plate, No , Y=92.6, x=0.3136, y=0.3196) at 2 observation angle with a C illuminant source (16). 2

7 Effect of Cherry Laurel Madmalade... Ash, fat, and titratable acidity were determined using the method given by Case et al. (17), and titratable acidity results were expressed as lactic acid. Nonfat dry matter (NFDM) contents of yogurt samples were calculated. The ph of each sample was measured with a digital ph meter (digital ph meter, Hanna, Italy) equipped with a glass electrode that was inserted directly into the yogurt sample for the measurement. The syneresis was determined at 5 ml of yogurt centrifuged at 5000 rpm for 20 minutes at 4 C, The syneresis rate (%) was expressed as volume of separated whey per 100 ml of yogurt (18). Viscosity measurements were taken at 15 C with a Brookfield viscometer (Model DV-1±; Brookfield Engineering Laboratories, Inc., MA) Sensorial Characteristics The panelists were asked to evaluate each sample in turn covering a list of judged parameter attributes using a hedonic scale with 1 being the worst (5 = like very much; 3 = neither like nor dislike; 1 = dislike extremely). The qualities judged were: exterior appearance (by looking to yogurt sample in daylight directly), consistency by spoon (by gentle mixing yogurt with a spoon) and by mouth, smell and taste intensity, perceived fruit. For consistency by mouth, odor and taste intensity, and perceived fruit and sweetness, a spoon of yogurt is taken and spread out by tongue. The overall acceptability was calculated as sum of the scores of the parameters judged. The yogurts were evaluated on 1, 7, 14, and 21 days of storing by eight panelists familiar with yogurt. Water was provided for mouth washing between samples. Statistical Analysis Statistical analyses of data for effects of fruit marmalade on physicochemical and sensory properties of yogurt were analyzed by ANOVA procedures using SPSS statistical software (19). The differences between means were evaluated by the Duncan s multiple range tests. RESULTS and DISCUSSION Table 1 shows the total solid, ash, fat and nonfat dry matter (NFDM) contents of the yogurt samples. As shown at Table 1, marmalade rates significantly (P<0.05) affected total dry matter and the highest score were observed in the samples with 20% marmalade (20.28 g/100 g) while the lowest score (13.77g/100 g) observed in samples (control yogurt) without marmalade. The average fat contents of the yogurts ranged from 2.90% to 2.55%. Expectedly, the adding of marmalade decreased the fat contents of the samples significantly when compared to control samples (P<0.05). The mean fat content of the stirred yogurts was similar to that found by Tarakç and Küçüköner (20), Rahman et al. (21) and Cinbafl and Yaz c (22) for yogurts addition blueberries, but lower than that reported by Yaz c and Akgün (23). Nonfat dry matter (NFDM) contents of yogurts increased significantly with added marmalade, but decreased ash contents especially after added 15% marmalade (P<0.05). This decreasing in ash contents of yogurts might be due to decreasing ash content of Cherry laurel marmalade. Figure 1 shows titratable acidity of yogurts during storage time. Titratable acidity of yogurts detected between 0.87 and 1.56, and increased significantly up to 14 th day of the storage (P<0.05), and did not show any statistical difference on 14 th and 21 st day for all treatments. Çelik et al. (14) found that through three weeks of storage in refrigeration, yogurt flavored with berries significantly increased its acidity. Singh and Muthukumarappan (24) reported a similar increase in acidity of control and calcium enriched fruit yogurt during storage. Marmalade concentrations were not affected titratable acidity of yogurts (P>0.05). The ph values decreased significantly (P<0.05) in each yogurt sample during the storage time. The ph of all yogurts decreased gradually up to 14 days, and after a slightly increase was observed Table 1. The mean values of some properties of yogurts Yogurt Total solid (%) Ash (%) Fat (%) NFDM (%) CY 13.77±0.13 e 0.97±0.03 a 2.90±0.00 a 10.87±0.13 e K ±0.19 d 0.94±0.01 a 2.75±0.07 ab 12.17±0.14 d K ±0.21 c 0.95±0.03 a 2.75±0.07 ab 14.15±0.27 c K ±0.39 b 0.87±0.02 b 2.60±0.14 b 16.54±0.53 b K ±0.23 a 0.81±0.02 c 2.55±0.07 b 17.73±0.16 a CY (Control), K1 (5% marmalade), K2 (10% marmalade), K3 (15% marmalade) and K4 (20% marmalade) abcde Letters indicate significant differences among yogurts with added marmalade, P<

8 H. Temiz, Z. Tarakçı, A. Islam Figure 1. Effect of marmalade concentration on titratable acidity of yogurts. CY: control, K1: 5%, K2: 10%, u K3: 15% and K4: 20% marmalade. for control and K1 samples (Figure 2). The increase at 14 and 21 days of storage was not significant (P>0.05). The lowest ph was reached after 14 days of storage. Especially, K4 sample had greater ph value (4.25), when compared to other samples. In a similar experiment, Öztürk and Öner (25) observed that the ph decreased during storage at 4 C for 21 days. Similar results were reported by Cueva and Aryana (16), Küçükçetin (26), Sahan et al. (27), Kailasapathy et al. (28), and Ramirez-Sucre and Velez-Ruiz (29). In other study on yogurt added with banana (30), the acidity increased (0.93, 0.96, 0.98 g/100 ml) while ph decreased (4.38, 4.37, 4.36) with storage time (0, 7, 14 days, respectively). In consequence of fermentation of lactose by bacteria, lactic acid and galactose increases. Decreasing of ph may be due to use sugar and organic acids of yeasts. As sugar sources finish, microorganisms begin to consume proteins, and which results in some by products that increase ph (31). Syneresis is defined as spontaneous water release from the gel caused by contraction. The most important causes for syneresis in fermented products include the use of high temperatures of incubation, low solid content or inadequate storage temperatures (32). There were significant (P<0.05) differences in syneresis over 1, 7, 14, 21 days. Values decreased on 14 th days and increased on 21 st day (Figure 3). Similar results were reported by Boeneke and Aryana (32) for lemon yogurt. The addition of marmalade caused a decrease of syneresis values in all samples of the yogurt, and differences between the control and the other samples were significant (P<0.05). Yogurt formulated with K1 showed the highest syneresis (45.75mL/100 g), while the sample formulated with K4 showed the lowest syneresis (39.00 ml/100 g), even lower than the control sample (48.25 ml/100 g). This could be attributed to the availability of fiber from cherry laurel fruit, which has higher water-holding capacity (33). These results indicated that the fruit concentration used in marmalade had an important effect on the syneresis of yoghurt. Similar results were reported by Cueva and Aryana (16). Storage times also affected syneresis significantly (P<0.05). In general, syneresis value of all yogurt samples decreased until 14 days of storage, and then increased except for K3. Similar results were reported for yogurt prepared with jack fruit juice (21) and for yogurt prepared with banana pure and sugar combinations (34). Those results were similar to that reported by Küçükçetin (26) which reported that the levels of syneresis decreased as the final fermentation ph decreased. Figure 2. Effect of marmalade concentration on ph of yogurts. CY: control, X K1: 5%, K2: 10%, _ K3: 15% and K4: 20% marmalade Figure 3. Effect of marmalade concentration on syneresis of yogurts. CY: control, X K1: 5%, K2: 10%, _ K3: 15% and K4: 20% marmalade 4

9 Effect of Cherry Laurel Madmalade... The viscosity is one of the typical major parameters for semiliquid food products. Viscosity measurement was applied successfully in the evaluation of yogurt texture (32). The viscosity of yogurt was affected significantly (P<0.05) by both marmalade concentration and storage time (Figure 4). The viscosity of the control and fruit-flavored yogurt decreased rapidly up to the day 14, and then remained constant during the other period of storage. Figure 4. Effect of marmalade concentration on viscosity of yogurts. CY: control, X K1: 5%, K2: 10%, _ K3: 15% and K4: 20% marmalade Yogurt formulated with fruit marmalade K4 showed the highest viscosity while the sample formulated with K2 showed the lowest viscosity, and even lower than the control sample at 1 and 14 days of storage time. But viscosity values were detected at the lower levels for K3 and K4 yogurts when compared to other treatments at 14 and 21 days of storage time (Figure 4). Similar results were reported by Çelik et al. (14). On the other hand, the viscosity of the fruit-flavored yogurts was influenced by the rates of the fruit addition. The addition of the fruit marmalade reduced the mean viscosity values when compared to control samples. The addition of large amounts of concentrated fruit juices decreases the water-holding capacity of protein (i.e. diluting the protein content in the milk base); thus the viscosity of the yogurt decreases (35). The color characteristics of the yogurts are shown in Table 2. Although the L* (whitenessdarkness) and b* (yellowness/blueness) color values of yogurts decreased by marmalade addition, a* (greenness-redness) values increased significantly (P<0.05). The L* value for the control was significantly higher than the L* values of the other treatments. Increasing marmalade ratios in yogurts had a darker yellow color with a higher degree of luminosity than that of the control yogurt. These results are agreement to the findings of Calvo et al. (35) on the perception of color in various fruit-flavored yogurts. This situation was also acceptability in the industrial production of fruit added yogurt, for which color intensity does meet the consumers acceptance. In the present study, L*, a* and b* values were fluctuated during the storage time. But b* values of the all samples increased at the end of storage time which might be due to conversion of the coloured flavylium cation of anthocyanin into colourless or yellowish forms. Similar results were reported by Needs et al. (36), Scibisz et al. (7) and Cinbafl and Yaz c (22) for yogurts addition blueberries. Table 2. Effect of marmalade concentration on color values of yogurts Storage periods (day) Properties Yogurt L* value CY 93.93±0.19 a, A 93.05±0.29 a, A 93.22±0.29 a, A 89.82±1.99 a, B K ±1.33 b, B 76.08±0.51 b, B 80.25±0.91 b, A 83.04±1.64 b, A K ±1.61 c, B 72.07±3.76 b, A 73.53±0.74 c, A 71.10±0.45 c, A K ±0.57 d, B 66.98±1.73 c, A 67.03±0.04 d, A 65.30±0.67 d, A K ±0.34 e, B 60.81±0.16 d, A 61.18±0.65 e, A 60.36±1.02 e, A a* value CY -2.84±0.08 e, A -2.81±0.09 e, A -2.88±0.23 e, A -3.48±0.21 e, B K1 4.81±0.54 d 4.17±1.04 d 3.85±0.06 d 3.25±0.08 d K2 6.85±0.01 c 6.61±0.20 c 6.62±0.03 c 6.88±0.39 c K3 8.29±0.11 b, B 9.02±0.28 b, A 8.51±0.13 b, AB 9.01±0.14 b, A K4 9.10±0.31 a, B 10.54±0.19 a, A 9.85±0.56 a, AB a, AB 9.91±0.17 b* value CY 11.11±0.23 a, B 10.50±0.56 a, B 10.01±0.12 a, B 13.59±0.82 a, A K1 7.06±0.38 b, AB 6.51±1.20 c, B 7.81±0.12 d, AB 8.39±0.35 b, A K2 6.31±0.16 c, B 8.13±0.60 bc, A 8.51±0.03 c, A 8.57±0.38 b, A K3 6.32±0.23 c, C 9.12±0.04 ab, A 8.75±0.06 bc, B 9.15±0.08 b, A K4 6.25±0.24 c, B 9.69±0.02 ab, A 9.40±0.53 ab, A 9.59±0.48 b, A CY (Control), K1 (5% marmalade), K2 (10% marmalade), K3 (15% marmalade) and K4 (20% marmalade) abcde Letters indicate significant differences among yogurts with added fruit marmalade (in columns), P<0.05. ABC Letters indicate significant differences among storage times (in lines), P<

10 H. Temiz, Z. Tarakçı, A. Islam Yogurt texture characterization is important for product and process development, and quality control to ensure consumer acceptability (37). Sensory evaluations have indicated a marked preference for the fruity and sweet characteristics of yoghurt (38). This characterization can be done using either instrumental or sensory measurements (39). The sensorial evaluation results of the fruitflavored yogurts are illustrated in Table 3. Results of sensorial evaluation showed that significant differences were observed among yogurt samples (P<0.05). The addition of marmalade at different rates to yogurt affected the scores for appearance and color significantly (P<0.05), and overall acceptability, whereas no significant effect (P>0.05) was observed for body and texture, and flavour. The lowest overall acceptability scores from marmalade-added yogurts were detected for K1 samples, while the higher overall acceptability scores were detected for K3. Storage times affected flavour and overall acceptability scores significantly (P<0.05). Flavour scores were similar to 1 st and 7 th day and then decreased significantly (P<0.05). In general, the flavour scores at the day 21 were lower than the other days. Similar results were reported by Cueva and Aryana (16). The overall acceptability scores decreased significantly (P<0.05) during storage time. At the 21 st day the yogurts had become the lower overall acceptability scores. Because, the acidity values at the 21 st day reached to the higher values. Diacetyl, lactic acid and acetaldehyde contribute most to the final flavour, and their concentrations and relative levels determine the general quality of the product and its acceptance by consumers (40). With respect to sensorial scores, in the production of fruit marmalade yogurt, it can be concluded that the addition of 15% and 20% fruit marmalade would be recommended. CONCLUSION Effects of cherry laurel marmalade on physicochemical and sensorial properties of yogurts were investigated. The addition of cherry laurel marmalade to the yogurts led to a remarkable decrease of the viscosity, syneresis, L*, and b* values of the yogurts. During storage, yogurt ph and syneresis decreased, but the titratable acidity, L* and b* increased. Sensory evaluations showed that appearance and color, body and Table 3. Effect of marmalade concentration on sensorial scores of yogurt Storage periods (day) Properties Yogurt YTX CY 4.63± ± ± ± a K1 4.12± ± ± ± b Appearance K2 4.25± ± ± ± b and color K3 4.25± ± ± ± ab K4 4.12± ± ± ± b RTX CY 4.50± ± ± ± a K1 3.37± ± ± ± b Body and K2 3.87± ± ± ± b texture K3 3.75± ± ± ± b K4 3.50± ± ± ± b RTX CY 4.25± ± ± ± a K1 3.75± ± ± ± b Flavour K2 3.62± ± ± ± b K3 4.37± ± ± ± b K4 4.00± ± ± ± b RTX 4.00 A 3.90 A 3.62 B 3.57 B CY 13.39± ± ± ± a K ± ± ± ± e Overall K ± ± ± ± d acceptability K ± ± ± ± b K ± ± ± ± c RTX A B C D CY (Control, with no marmalade), K1 (5% marmalade), K2 (10% marmalade), K3 (15% marmalade) and K4 (20% marmalade) abcde Letters indicate significant differences among yogurts with added fruit marmalade (YTX), P<0.05. ABCD Letters indicate significant differences among storage times (RTX), P<

11 Effect of Cherry Laurel Madmalade... texture were not affected significantly by storage time, while flavour and overall acceptability values affected significantly. In the sensorial evaluations, K3, containing 15% cherry laurel marmalade was preferred over other marmalade-added samples. The results revealed that Cherry laurel fruit can be used in manufacture of yogurt for increasing consumption, but further investigations are needed to achieve the best physico-chemical and sensory characteristics of the final product, and in particular, the effect of different stabilizing agents should be investigated for fruit-flavored yogurts. REFERENCES 1. Alasalvar C, Al-Farsi M, Shahidi F Compositional characteristics and antioxidant components of cherry laurel varieties and pekmez. J Food Sci, 70: Islam A 'Kiraz' Cherry Laurel. N Z J Crop Hortic Sci, 30: Baytop T. (1984. Türkiye de Bitkilerle Tedavi; Istanbul Üniversitesi Eczacilik Fakültesi Yay nlar, No. 40, Istanbul Liyana-Pathirana CM, Shahidi F, Alasalvar C Antioxidant activity of cherry laurel fruit (Laurocerasus officinalis roem.) and its concentrated juice. Food Chem, 99: Ayaz FA, Kadioglu A Changes in fatty acid composition of cherry laurel (Laurocerasus officinalis Globigemmis ) fruit during maturation. N Z J Crop Hortic Sci, 28: Amellal-chibane H, Benamara S Total contents of major minerals in the nature yoghurt and in the yoghurts with the date powder of three dry varieties. Am J Food Nutr, 1: Scibisz I, Ziarno M, Mitek M, Zareba D Effect of probiotic cultures on the stability of anthocyanins in blueberry yoghurts. LWT - J Food Sci Technol, 49: Aportela-Palacios A, Sosa-morales ME, Velez- Ru z JF Rheological and physicochemical behavior of fortified yoghurt, with fiber and calcium. J Tex Stud, 36: Chouchouli V, Kalogeropoulos N, Konteles SJ, Karvela E, Makris DP, Karathanos VT Fortification of yoghurts with grape (Vitis vinifera) seed extracts. LWT - J Food Sci Technol, 53: Tarakç Z Influence of Kiwi marmalade on the rheology characteristics, color values and sensorial acceptability of fruit yogurt. Kafkas Universitesi Veteriner Fakültesi Dergisi, 16: Mataragas M, Dimitriou Skandamis VPN, Drosinos EH Quantifying the spoilage and shelf-life of yoghurt with fruits. Food Microbiol, 28: Tamime AY, Robinson RK Yogurt Science and Technology, 3 rd Edition Woodhead Publishing, Cambridge, England, 619 p. 13. Sanchez-Segarra PJ, Garcia-Martinez M, Gordillo-Otero MJ, Diaz-Valverde A, Amaro-Lopez MA, Moreno-Rojas R Influence of the addition of fruit on the mineral content of yoghurts: nutritional assessment. Food Chem, 70: Çelik S, Bak rc I, Sat IG Physicochemical and organoleptic properties of yogurt with Cornelian Cherry paste. Int J Food Prop, 9: Guggisberg D, Cuthbert-Steven J, Piccinali P, Bütikofer U, Eberhard P. Rheological, microstructural and sensory characterization of low-fat and whole milk set yoghurt as influenced by inulin addition. Int Dairy J, 19: Cueva O, Aryana KJ Quality attributes of a heart healthy yogurt. LWT-Food Sci Technol, 41: Case RA, Bradley RL, Williams RR. 1985, Chemical and physical methods. In: Standard Methods for the Examination of Dairy Products, Ed. Richardson, G.H., 15 th Ed., American Public Health Association, Baltimore, USA, Larmond E Laboratory methods for sensory evaluation of food, Canadian Goverment Publishing Center, Ottawa, Canada, 70 p. 19. SPSS Statistical Software, SPSS 10.0 for Windows, SPSS Inc., Chicago IL, USA 20. Tarakç Z, Küçüköner E Physical, chemical, microbiological and sensory characteristics of some fruit-flavored yogurt. J Food Sci Technol, 41: Rahman, SMR, Rashid MH, Islam MN, Hassan MN, Hasan S Utilization of jack fruit juice in the manufacture of yogurt. J Biol Sci, 1: Cinbafl A, Yaz c F Effect of the addition of blueberries on selected physicochemical and sensory properties of yogurts. Food Technol Biotechnol, 46:

12 H. Temiz, Z. Tarakçı, A. Islam 23. Yaz c F, Akgün A Effect of some protein based fat replacers on physical, chemical, textural, and sensory properties of strained yogurt. J Food Eng, 62: Singh G, Muthukumarappan K Influence of calcium fortification on sensory, physical and rheological characteristics of fruit yogurt. Food Sci Technol, 41: Öztürk BA, Öner MD Production and evaluation of yogurt with concentrated grape juice. J Food Sci, 64: Küçükçetin A Effect of heat treatment of skim milk and final fermentation ph on graininess and roughness of stirred yogurt. Int J Dairy Technol, 60: Sahan N, Yasar K, Hayaloglu AA Physical, chemical and flavour quality of non-fat yogurt as affected by a b-glucan hydrocolloidal composite during storage. Food Hydrocoll, 22: Kailasapathy K, Harmstorf I, Phillips M Survival of Lactobacillus acidophilus and Bifidobacterium animalis ssp. lactis in stirred fruit yogurts. Food Sci Technol, 41: Ramírez-Sucre MO, Vélez-Ruiz JF Physicochemical, rheological and stability characterization of a caramel flavored yogurt. LWT - Food Sci Technol, 51: Bakirci I, Kavaz A An investigation of some properties of banana yogurts made with commercial ABT-2 starter culture during storage. Int J Dairy Technol, 61: Amaya-Llano SL, Martinez-Alegria AL, Zazueta- Morales JJ, Martinez-Bustoe F Acid thinned jicama and maize starches as fat substitute in stirred yogurt. Food Sci Technol, 41: Boeneke CA, Aryana KJ Effect of folic acid fortification on the characteristics of lemon yogurt. Food Sci Technol, 41: García-Pérez FJ, Lario Y, Fernández-López J, Sayas E, Pérez-Alvarez JA, Sendra E Effect of orange fiber addition on yogurt color during fermentation and cold storage. Color Res Applicat, 30: Akyüz N, Coflkun H Production of fruit yogurt in yogurt. National Productivity Center, Mert Pres No; 548. Ankara, Calvo C, Salvador A, Fiszman SM Influence of colour intensity on the perception of colour and sweetness in various fruit-flavoured yogurts. Euro Food Res Technol, 213: Needs E, Capellas M, Bland P, Manoj P, Mcdougal D, Paul G Comparison of heat and pressure treatments of skim milk, fortified with whey protein concentrate, for set yogurt preparation: effects on milk proteins and gel structure. J Dairy Res, 67: Ares G, Goncalvez D. Pérez C, Reolón G, Segura N, Lema P, Gámbaro A Influence of gelatin and starch on the instrumental and sensory texture of stirred yogurt. Int J Dairy Technol, 60: Nongonierma AB, Cayot P, Springett M, Quere JLL, Cachon R, Voilley A Transfers of small analytes in a multiphasic stirred fruit yoghurt model. Food Hydrocoll, 21: Çelik S, Bak rc I Some properties of yogurt produced by adding mulberry pekmez (concentrated juice). Int J Dairy Technol, 56: Hussein MM, Hassan FAM, Abdel Daym HH, Salama A, Enab AK, Abd El-Galil AA Utilization of some plant polysaccharides for improving yoghurt consistency. Ann Agric Sci, 56:

13 GIDA (2014) 39 (1): 9-15 doi: /gida GD13058 Research / Araflt rma DETERMINATION OF STARTER CULTURE PROPERTIES OF LACTIC ACID BACTERIA ISOLATED FROM CHEESE İlkay Turhan 1 *, Zübeyde Öner 2 1 T.C. stanbul Arel University, School of Health Sciences, Nutrition and Dietetic Department, stanbul 2 Süleyman Demirel University, Faculty of Engineering, Food Engineering Department, Isparta Received / Gelifl tarihi: Accepted / Kabul tarihi: Abstract In this study, starter properties of 83 lactic acid bacteria (LAB) strains which were isolated from 13 cheese samples that were produced from raw milk and were characterized by using phenotypic, API and FTIR spectroscopy methods were determined. Proteolytic activity, acidification and decarboxylase activity were analyzed as starter culture properties for 22 Lactococcus sp., 36 Enterococcus sp. and 25 Lactobacillus sp. of 83 LAB. 18 isolates could decrease ph to less than six in 6 hours, 38 isolates indicated lower than 20 µg tyrosin/ml proteolytic activity and also 42 isolates indicated no decarboxylase activity. These isolates are thought to be the appropriate starter culture for cheese industry. Keywords: Starter culture, proteolytic activity, acidification and decarboxylase activity PEYNİRDEN İZOLE EDİLEN LAKTİK ASİT BAKTERİLERİNİN STARTER KÜLTÜR ÖZELLİKLERİNİN BELİRLENMESİ Özet Bu çal flmada çeflitli iflletmelerden al nan çi sütten üretilmifl 13 adet peynir örne inden izole edilen ve biyokimyasal, API test kitleri, FTIR spektroskopisi yöntemleri ile tan lar gerçeklefltirilen 83 adet laktik asit bakterisi (LAB) suflunun bafllang ç kültür olma özellikleri belirlenmifltir. 22 si Lactococcus sp., 36 s Enterococcus sp. ve 25 tanesi Lactobacillus sp. olarak belirlenmifl izolatlar n bafllang ç kültür olma özelliklerinden olan asit oluflturma yetene i, proteolitik aktivite ve dekarboksilaz aktiviteleri incelenmifltir. 18 izolat, 6 saatte ph y 6 n n alt na düflürmesi; 38 izolat, 20 µg tirosin/ml miktar n n alt nda bir proteolitik aktivite göstermesi ve 42 izolat, hiçbir dekarboksilaz aktivitesi göstermemesi aç s ndan peynir endüstrisine uygun bafllang ç kültür olabilece i düflünülmüfltür. Anahtar kelimeler: Starter kültür, asit oluflturma, proteolitik aktivite, dekarboksilaz aktivitesi *Corresponding author/ Yazışmalardan sorumlu yazar ilkayturhan@arel.edu.tr, (+90) / 1175, (+90)

14 İ. Turhan, Z. Öner INTRODUCTION The most important desired properties for cheese are its texture, flavor, taste, aroma, smell and appearance. The raw milk quality, total dry matter, protein content of raw matter, acidity, properties of starter cultures and additives used are factors that affect these properties during production of cheese. Kashar cheese is one of the most important cheeses in Turkey (1, 2). Lactic acid bacteria, especially in milk and milk products, are widely available in nature. LAB are widely used as starter cultures for fermentation in the dairy, meat and other food industries. Their properties have been used to manufacture products like cheese, yoghurts, etc. The most important feature of these microorganisms increases acidity of milk by producing lactic acid from lactose. The increasing of acidity affects the stability of casein as well as and promotes the activity of rennin. After acidification, milk proteins begin coagulation. In addition, due to the lipolytic and proteolytic activities during cheese ripening, lactic acid bacteria have a significant impact on the formation of characteristic taste, aroma and texture (3-5). Acid production, proteinase and peptidase activity of LAB and many other features like these are important for their using as a starter culture. Proteolytic systems of LAB include their cell membrane proteins, amino acid and peptide transport systems and many of the intracellular peptides and proteases (6). Proteolysis is important for the formation of the specific taste of cheese (6, 7) and different LAB species have different proteolytic activity (6, 8, 9). In this study, ability of producing acid, proteolytic activity and decarboxylase activities of lactic acid bacteria, which were isolated from Kashar cheese and diagnosed by biochemical tests and FTIR spectroscopy method, were determined. MATERIALS AND METHODS Material A total of 12 Kashar cheese and 1 White cheese samples which were produced in laboratory conditions and were supplied from various factories were used as isolation materials. For the characterization of LAB, biochemical tests and FTIR Spectroscopy (Perkin Elmer, Spectrum 100) method was applied. In order to identify isolates according to using of carbohydrates, BD BBL Crystal Gram-Positive ID Kits were used for isolates that was determined as coccus and biomerieux API 50 CHL (Ref to 10 x 10 ml) test kits were used for isolates that was determined as bacillus (10). Total 157 isolates were obtained from all samples as a result of isolation procedures. The physiological and biochemical analyzes were continued with 83 isolates in consequence of morphological characteristics, catalase activities, and gram reactions. Biochemical tests were carried out according to the Sherman classification. Cocci that could grow under such conditions 10 C, 15 C, 45 C, 6.5 % NaCl and ph 9.6 were identified as enterococci and the rest of the cocci strains were evaluated as lactococci. Taking into account these criteria, 36 of 83 isolates was approved as Enterococcus sp. and 22 of them was approved as Lactococcus sp. according to their phenotypic characteristics. All of the 25 isolates which were morphologically identified as bacilli was evaluated as Lactobacillus sp. because of being able to grow at 15 C (10). After these cultures were isolated and identified, acidification, proteolytic and decarboxylase activity of bacteria were determined in order to determine starter culture properties of isolated bacteria (10). METHODS Determination of acidification activity 1% of the active cultures were inoculated to the tubes which contain 5 ml Skim Milk medium. After Lactococcus sp. at 28 C, Lactobacillus sp. at 30 C and Enterococcus sp. at 37 C were incubated for 18 hour, 1% of the cultures were inoculated into other tubes which contain 5 ml Skim Milk medium. The cultures were incubated for 6 and 24 hours at the appropriate temperatures and their ph was measured. ph values were determined taking into account the initial and final ph values (11, 12). 10

15 Determination of Starter Culture Properties of... Determination of Proteolytic Activity Isolated strains were grown in Skim Milk medium and proteolytic activity was measured by a spectrophotometer. Sterilized Skim Milk medium was used as a control in order to eliminate the proteolysis products which would come from the medium. Proteolytic activity was expressed as tyrosine equivalent (12, 13). Determination of Decarboxylase Activity Isolated cultures were inoculated into the base medium which was enriched with a variety of 2 % amino acids (histidine, tyrosine, lysine, ornithine, phenylalanine, and tryptophan) and incubated for 7 days at anaerobic conditions (14). After Lactococcus and Enterococcus strains were activated in M17 medium and Lactobacillus strains were activated in MRS medium, these strains were inoculated on M17 and MRS slope agar medium and Lactococcus sp. and Lactobacillus sp. were incubated at 30 C for 24 hours, Enterococcus sp. was incubated in the 37 C for 24 hours. At the end of this period, bacteria whose Mac Farland adjustment was done were inoculated in media which contain amino acids and amino acid-free media which used as a control and then were incubated in the anaerobic conditions at 30 C for 7 days (14). RESULTS and DISCUSSION Acid Production Activities of Isolates ph changes at 6 h and 24 h is given in Table 1. for isolates were evaluated as Lactococcus sp., Enterococcus sp. and Lactobacillus sp.. When it was considered Karakus (15) s evaluation in the study with white cheese, it was determined all isolates that was evaluated as Lactococcus sp. were produced low acid level ( ph <1.00) in our study. It was pointed out that Lactococcus strains which have good acid production should reduce ph under 5.3 at the end of 6 hours and at 30 C (16). In our study, only two strains of Lactococcus sp. isolates could reduce ph to 5.85 and Similarly, none of isolated L. lactis strains from Durlu-Özkaya et al. (17) s study with white cheese produced by using goat's milk could not reduce ph to 5.0 ± 0.2 at 6 hours. 17 of 27 L. lactis which were isolated from Orinotyri cheese produced by using goat milk strains showed slow acid production ( ph 0.00 to 0.18), while the rest of 10 isolates showed the middle level acid production ( ph 0.20 to 0.54) in the first 6 hours in Prodromou et al. (18)'s study. In the same study, only one of isolates each Enterococcus sp. and Lactobacillus sp. could reduce ph under 6 within 6 hours. In Elçio lu (19) s study, it has been pointed out that only 2 of Lb. plantarum, 2 of E. durans and one of E. faecium's, from 96 of isolates from Karg Tulum cheese, can be used for preparation of starter culture because of their rapid acidification. In Da demir (20)'s study with white cheese, ph changes for both Enterococcus sp. and Lactobacillus sp. varied low levels in 6 hour. It is observed that both enterococci and lactobacilli were capable of producing acid more slowly than lactococci in Tunail et al. (12)'s study. In our study, two isolates evaluated as Enterococcus sp. reduced the ph level to 4.08 in 24 hours, may be preferred as an alternative acid producing culture in the cheese production as their acidity is close to the level of acidity of Lactococcus sp. isolates which show highest possible levels of acidity. However, as the isolates evaluated as Lactobacillus sp. could reduce the ph level to maximum 4.48 within 24 hours and therefore, lactobacilli were not considered to be at the level sufficient to be selected as an acid producing culture. Proteolytic Activity of Isolates Proteolytic activity values (PAV) which were expressed as tyrosine equivalent of Lactococcus sp., Enterococcus sp. and Lactobacillus sp. cultures were given as µg tyrosine / ml in Table 1. Tyrosine curve value (R 2 ) was It is known that proteolytic activity is an important property for selection of starter culture. Proteolytic activity of cultures which will be selected is required to be low or high according to the type of cheese. While cultures which produced low proteolytic activity are preferred for fresh cheeses, cultures with high proteolytic activity are required for matured hard cheeses (12, 21). Proteolytic activity values (PAV) were assessed as weak level (PAV < 10.00), mid-level (10.00 <PAV < 20.00) and strong level (PAV> 20.00) at Karakus (15) s study with white cheese. 11

16 İ. Turhan, Z. Öner Table 1. Acidification values of Lactococcus sp. Lactobacillus sp. and Enterococcus sp. strains at 6 h and 24 h and proteolytic activities Acidification Proteolytic activities Species ph (6h) ph (24 h) µg tyrosin / ml E. faecalis (n=27) Minimum Maximum Mean 0.58± ± ±89.46 Enterococcus sp. (n=9) Minimum ,26 1,6 Maximum 0.7 2,44 210,5 Mean 0.45±0.19 1,67± ,27±65.55 L. lactis (n=17) Minimum Maximum Mean 0.49± ± ±10.38 L. cremoris (n=3) Minimum Maximum Mean 0.12± ± ±4.11 L. diacetylactis (n=2) Minimum Maximum Mean 0.34± ± ±2.26 Lactobacillus sp. (n=13) Minimum Maximum Mean 0.37± ± ±6.03 L. plantarum (n=12) Minimum Maximum Mean 0.28± ± ±22.52 According to the evaluation of the study, it was determined that % of the isolates had mid level proteolytic activity and % of them had strong level proteolytic activity in our study. PAV average (25.95 mg tyrosine / ml) of Lactobacillus sp. isolates and PAV average (21.8 mg tyrosine / ml) of Lactococcus sp. isolates was found very close. It is also found that PAV average (60.3 mg tyrosine / ml) of Enterococcus sp. isolates were quite high and PAV average of 25 % (9 isolates) of them is higher than PAV average (60.3 mg tyrosine / ml) of all the enterococci strains. While PAV values of lactococci and lactobacilli isolates were close to each other, values of enterococci isolates changed between wide limits (from 29.3 to µg of tyrosine / ml) and 36 % of them was found to have higher proteolytic activity than 60 µg tyrosine / ml at Durlu-Özkaya et al. (17)'s study with cheese produced by using raw goat milk. Similar results were found at Tunail et al. (12)'s study and Da demir (20) s study, in general Enterococcus sp. especially E. faecium strains had high proteolytic activity. Prodromou et al. (18) isolated 27 L. lactis strains from Orinotyri cheese produced by using raw goat milk and determined that 9 of them had low proteolytic activity (<50 µg glycine / ml), 7 of them had medium proteolytic activity (50 to 150 µg glycine / ml), and 3 of them had high proteolytic activity (> 150 µg glycine / ml). Determination Decarboxylase Activity of Isolates Microorganisms which have decarboxylase activity can form biogenic amine by enzymatic decarboxylation of amino acids in foods. Histamine poisoning results from consumption of foods typically certain types of fish and cheeses that contain unusually high levels of histamine. Therefore, decarboxylase activity is an important problem at the selection of culture. In this study Joosten and Northolt (14) s method was used to determine decarboxylase activity. Biogenic amine forming capabilities of the cultures by using histidine, tyrosine, lysine, ornithine, phenylalanine, tryptophan, amino acids were determined as shown in the Table 2. 12

17 Determination of Starter Culture Properties of... Table 2. Decarboxylase activities Species Orn His Tyr Trp Phe Lys E. faecalis (n=27) Enterococcus sp. (n=9) L. cremoris (n=3) L. diacetylactis (n=2) L. lactis (n=17) Lactobacillus sp. (n= 13) Lb. plantarum (n=12) 0 0 3* 2* 0 0 Orn: Ornithine, His: Histidine, Tyr: Tyrosine, Trp: Tyrptophane, Phe: Phenilalanine, Lys: Lysine *: Weak reaction. Table 3. Acidification and proteolytic activities of selected isolates Acidification Proteolytic activities Species ph (6h) ph (24 h) µg tyrosin / ml Lc12 (L. lactis) Lc13 (L. lactis) Lb74 (Lb. fermentum) E33 (Enterococcus sp.) It was determined that white cheeses include a high proportion of Tyramine (22, 23). Enterococci, lactobacilli and lactococci isolated from cheeses produce the most of tyramine (24). Durlu-Özkaya et al. (17) reported that lactococci and lactobacilli strains isolated from white cheese didn t reduce none of histidine, tyrosine, lysine, ornithine, phenylalanine and threonine amino acids, on the contrary all of the enterococci except two of them decarboxylated tyrosine. Similar results were also obtained from Tunail et al. (12) s study. It was reported that tyramine is the only biogenic amine produced by Enterococcus sp. in milk (25-27). Tuncer (28) determined that all 36 of 39 enterococci isolates except 3 of them isolated from Tulum cheese, formed tyramine from the tyrosine amino acid. It was determined that determination of decarboxylase activity of strains by using medium does not show very healthy results (12, 24, 29, 30). Kucerová et al. (31) assigned that 20 of 33 Enterococcus strains isolated from fresh cheese and semi-hard cheese produced by using raw cow's milk, had tyrosine decarboxylase activity. Joosten and Northolt (14) assigned that only 5 Lb. buchneri of lactobacilli strains isolated from cheese produced by using raw milk, had histidine decarboxylase activity and one Lb. brevis of them had tyrosine decarboxylase activity. CONCLUSION As a result, when acid producing capabilities, proteolytic activities and decarboxylase activities of isolates were evaluated, it was determined that Lc12 (L.lactis) ve Lc13 (L. cremoris) isolates among lactococci, Lb74 (Lb. fermentum) isolate among lactobacilli and E33 (Enterococcus sp.) isolate among enterococci showed the best starter characteristics (Table 3.). All of these isolates could reduce < 6 ph in 6 hours, have had moderate proteolytic activity (<20 mg tyrosine / ml) and were decarboxylase negative isolates. To research possibilities of these isolates to be used as a starter culture, in terms of antibiotic resistance, phage susceptibility and aroma substances formation should be assessed. REFERENCES 1. Çetinkaya F, Soyutemiz GE Microbiological and chemical changes throughout the manufacture and ripening of Kashar: a traditional Turkish cheese. Turk J Vet Anim Sci, 30: Ürkek B Homojenizasyon ve ambalajlama iflleminin kaflar peynirinin baz kimyasal, biyokimyasal, elektroforetik, duyusal ve mikrobiyolojik özelliklerine etkisi. Yüzüncü Y l Üniversitesi Fen Bilimleri Enstitüsü G da Mühendisli i Anabilim Dal Yüksek Lisans Tezi, Van, Türkiye, 95 s. 13

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19 Determination of Starter Culture Properties of Öner Z, Karahan AG, Alo lu H Changes in the microbiological and chemical characteristics of an artisanal Turkish White cheese during ripening. LWT 39 (5) Durlu-Özkaya F, Alichanidis E, Litopoulou- Tzanetaki E, Tunail N Determination of biogenic amine content of Beyaz cheese and biogenic amine production ability of some lactic acid bacteria. Milchwissen, 54 (12): Celano GV, Cafarchia C, Buja F, Tiecco G Ricerca di amine biogene in alcuni formaggi. Ind Aliment.31: Giraffa G, Pepe G, Locci F, Neviani E, Carminati D Hemolytic activity, production of thermonuclease and biogenic amines by dairy enterococci. Ital J Food Sci 7 (4): Schirone M, Tofalo R, Visciano P, Corsetti A, Suzzi G Biogenic Amines in Italian Pecorino Cheese. Frontiers in Microbiol, NCBI, 3, Tuncer Y Some technological properties of phenotypically identified enterococci strains isolated from Turkish Tulum cheese. African J of Biotech, 8 (24): Sumner SS, Taylor SL Detection method for histamine-producing, dairy-related bacteria using diamine oxidase leucocrystal violet. J of Food Protect, 52 (2): Ayhan K, Alsancak-Ökan G, Noveir MR Determination of histidine decarboxylase activity produced by Enterobacteriaceae isolated from ground meat. Ciencia, 8 (2): Kucerová K, Svobodová H, Tûma S, Ondrácková I, Plocková M Production of Biogenic Amines by Enterococci. Czech J Food Sci, 27 (2):

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