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Öğe Determination of powder flow properties of skim milk powder produced from high-pressure homogenization treated milk concentrates during storage(ELSEVIER SCIENCE BV, 2018) Mercan, Emin; Sert, Durmus; Akin, NihatThe aim of this study was to determine effects of high-pressure homogenization (HPH) treatment to milk concentrates on powder flow properties of skim milk powders (SMP). For this purpose, SMP samples were produced from skim milk concentrates which were HPH treated at 0 (control), 50, 100 and 150 MPa. SMP samples were stored 180 days at 20 and 40 degrees C and caking, cohesion and powder flow speed dependency test (PFSD) were performed using a Powder Flow Analyzer. HPH treatment decreased cohesion and caking properties of SMPs. At the 0. day, cake strength of SMPs from HPH treated concentrates varied from 0.43-2.70 mN.m, whereas cake strength of SMP-0(control) was 8.20 mN.m. Cohesion index (CI) of samples ranged from 6.80-15.74 nun during storage. Based on CI, SMPs from HPH treated concentrates showed free and easy flowing flow behavior during storage at 20 and 40 degrees C. In addition, cohesion index at four speeds indicated that SMP from HPH treated concentrates were more flowable at even lower flow speeds then SMP-0. PFSD test verified that all SMP samples showed more free-flowing characteristics with increasing flow speeds. Flow stability of samples ranged from 0.95-1.15 and also flow stability of SMP-0 increased during storage at both 20 and 40 degrees C. The results revealed that HPH treatment to milk concentrates could improve powder flow properties of skim milk powders.Öğe Effect of high-pressure homogenisation on viscosity, particle size and microbiological characteristics of skim and whole milk concentrates(ELSEVIER SCI LTD, 2018) Mercan, Emin; Sert, Durmus; Akin, NihatEffect of high-pressure (HPH) homogenisation on milk concentrates were studied. Skim and whole milk concentrates were homogenised at 0-150 and 0-40 MPa, respectively, and viscosity, particle size measurement, microbiological and colour characteristics determined. Up to a pressure of 120 MPa, viscosity of HPH-treated skim milk concentrates (SMC) was proportional to HPH pressure and was lower than that of the control (0 MPa). With whole milk concentrates (WMC), HPH decreased viscosity up to a pressure of 20 MPa; above 30 MPa viscosity increased. According to a power law model, both skim and whole milk concentrates showed shear-thinning flow behaviour. HPH at pressures above 120 MPa completely inactivated the microbial load of SMC. Up to a pressure of 50 MPa, HPH decreased the mean particle size (D [3,2]) of SMC; an increasing trend of D [3,2] was observed above 70 MPa. Except at 40 MPa, HPH decreased D [3,2] values of WMC samples. (C) 2018 Elsevier Ltd. All rights reserved.Öğe The effect of milk type and heat treatment on physicochemical and microbiological properties of Tulum cheese whey(M H SCHAPER GMBH CO KG, 2013) Sert, Durmus; Akin, NihatIn this study, Tulum cheese produced by using cow, sheep, goat milk and mixtures of them and physicochemical and microbiological properties of these cheeses whey were analyzed. Two different methods were used in the cheese production. In the first method, traditional production type was used; for this reason, raw milk wasn't heated. In the second method, heat treated milk (60 +/- 2 degrees C 10 min.) was used. Dry matter was determined to be less in whey of cheeses produced from heat treated milk. It was determined that there were increases in fat losses with whey in cheeses that were produced from sheep and goat milk. Lowest protein content in dry matter was determined to be in whey of heat treated cow-sheep milks (50:50). Color values of whey significantly varied according to heat treatments among milk groups. The highest yeast-mold number was determined in whey of cheeses produced from raw sheep's milk. Lactococci count in whey varied between 2.38-6.35 log cfu/g in mesophilic flora, between 4.26-5.70 log cfu/g in termophilic flora. The lowest enterococci count was found in whey of cheeses made of cow milk.Öğe Effect of salep as a hydrocolloid on storage stability of 'Incir Uyutmasi' dessert(ELSEVIER SCI LTD, 2009) Ayar, Ahmet; Sert, Durmus; Akbulut, MehmetSalep is a natural stabilizing agent used widely in Turkish-type Maras ice cream and some milk desserts. The effect of salep addition on the storage stability of a representative Incir Uyutmas1 dessert, prepared from whole cows' milk, fig and sugar was Studied. Dry matter. pH, viscosity, water-holding capacity (WHC), color properties (L*, a* b* values), mineral matters (Al, Ca, Cu, Fe. K, Mg, Na, P and Zn), sensorial properties and microbial quality of desserts were affected by salep addition, sugar and fig concentrations. Salep addition caused an important increase in the viscosity and the WHC of dessert. Salep. sugar and fig improved the storage stability of the dessert. (C) 2007 Elsevier Ltd. All rights reserved.Öğe Effect of ultrasonic treatment on reduction of Esherichia coli ATCC 25922 and egg quality parameters in experimentally contaminated hens' shell eggs(WILEY-BLACKWELL, 2013) Sert, Durmus; Aygun, Ali; Torlak, Emrah; Mercan, EminBackround In this study, hen eggs which were experimentally contaminated with Esherichia coli ATCC 25922 were used. Contaminated eggs were washed statically (S5 to S30; 0 kHz) and by ultrasonic waves (U5 to U30; 35 kHz) for given applications of time (5, 15 and 30 min), then the eggs were stored at 22 degrees C for 14 days. Results Depending on the time of ultrasonic application, a significant increase in egg shell strength (P < 0.01) was recorded. The highest value of the Haugh unit (67.93, 1 day) was observed on the eggs which were washed by ultrasonic waves. Yolk width values of ultrasonic washed eggs diminished. E. coli was completely removed by 30 min of ultrasonic application. During storage E. coli growth was not detected on the eggs which were washed by ultrasonic waves except the eggs in U5 group (2.04 log CFU eggshell(-1)) on the first day of storage. Conclusion Depending on the time of ultrasonic application a significant increase in egg quality parameters (shell strength, albumen height, Haugh units, and yolk height) were observed. The application of ultrasound led to a significant reduction in E. coli numbers on egg shells. (c) 2013 Society of Chemical IndustryÖğe Effect of Whey Concentrate Addition on the Chemical, Nutritional and Sensory Properties of Tarhana (a Turkish Fermented Cereal-based Food)(KARGER, 2009) Ertas, Nilglin; Sert, Durmus; Demir, M. Kuersat; Elguen, AdemIn this study, Tarhana, which is a traditional and nutritious Turkish cereal food, was supplemented with whey concantrate (WC) in stead of yoghurt. The effects of WC addition on the chemical, nutritional and sensory properties of tarhana samples were determined and compared with the control sample made with yoghurt. The moisture, crude ash, protein and fat contents of the samples changed between 10.53 and 11.28%; 1.507 and 1.758%; 9.75 and 12.52%, and 0.87 and 6.33%, respectively. As major minerals, Mg, Ca, P, Na and K contents of WC added tarhana samples versus the control, increased, while protein amounts were decreasing, significantly (P<0.01). The addition of WC resulted the samples lighter in color and lower in acidity. The phytic acid contents of WC added tarhana samples are decreased significantly (P<0.01) by the fermentation. Tarhana sample with 12.5% WC which is equivalent to the yoghurt in solid amount, were judged with high overall acceptability values by the taste panelists. It may be acceptible up to 25% whey addition level with higher nutritional value.Öğe The effects of carbon dioxide addition to cheese milk on the microbiological properties of Turkish White brined cheese(WILEY-BLACKWELL, 2012) Dertli, Enes; Sert, Durmus; Akin, NihatThis study invest0igated the effect of CO2 added to achieve three pH levels: pH 6.1, pH 6.2 and pH 6.3 for treatments X, Y, Z, respectively, on some microbiological properties of Turkish White (TW) brined cheese. For each pH, four batches of cheese were produced from: raw milk with no added carbon dioxide (UR), raw milk with carbon dioxide (TR), pasteurised milk with no carbon dioxide addition (UP) and pasteurised milk with carbon dioxide addition (TP). The microbiological analysis of TW brined cheeses was carried out for 90 days of maturation period. Total aerobic mesophilic bacteria, mesophilic lactic acid bacteria, yeasts and moulds and coliform group were determined in control and CO2 treatment groups. Mesophilic bacteria count was determined as 5.14, 5.29, 5.67 log cfu/g for pH 6.1, 6.2 and 6.3, respectively, in CO2-treated raw milk cheeses. Yeasts and moulds reduction increased significantly by applying CO2 (P < 0.01). For TW cheese samples, the most significant microbial inactivation was detected at sample groups of pH 6.1.Öğe Effects of preincubation application of low and high frequency ultrasound on eggshell microbial activity, hatchability, supply organ weights at hatch, and chick performance in Japanese quail (Coturnix coturnix japonica) hatching eggs(OXFORD UNIV PRESS, 2015) Yildirim, Iskender; Aygun, Ali; Sert, DurmusThe aim of the current study was to establish the effects of preincubation application of low and high frequency ultrasound on egg weight loss, hatchability, supply organ weights, chick performance, and eggshell microbial activity in Japanese quail (Coturnix coturnix japonica). A total of 630 fresh eggs were randomly divided into 3 groups. Treatments were no ultrasound but eggs were sprayed with benzalkonium chloride solution (B), 35 kHz ultrasound applied for 30 min (U35), and 130 kHz ultrasound applied for 30 min (U130). At the beginning of the incubation, the eggs in the U130 treatment had lower coliform, Salmonella, and Staphylococcus counts than those in the B group. However, no significant differences were found in coliform, Salmonella, and Staphylococcus counts among treatments at d 14 of incubation. Among treatments, there were no significant differences in egg weight loss, hatchability, embryonic mortality, supply organ weights, spread of hatch, or relative growth.Öğe Effects of prestorage application of propolis and storage time on eggshell microbial activity, hatchability, and chick performance in Japanese quail (Coturnix coturnix japonica) eggs(POULTRY SCIENCE ASSOC INC, 2013) Aygun, Ali; Sert, DurmusPropolis, a resinous mixture produced by honeybees from substances collected from plants, has strong antibacterial and antifungal properties. The purpose of the current study was to establish the effects of prestorage application of propolis and storage time on eggshell microbial activity, egg weight loss, hatchability, and chick performance in quail hatching eggs. Treatments were compared in a 2 x 5 factorial design with 2 different storage times (7 and 14 d) and 5 prestorage applications (control, ethyl alcohol 70%, 5% propolis, 10% propolis, and 15% propolis solution). After application, the eggs were stored for 7 or 14 d at 13 C and 75 to 80% RH before incubation. Eggs sprayed with propolis had lower levels of total aerobic mesophilic bacteria, coliform, Salmonella spp., Staphylococcus spp., and mold yeasts than control eggs over the storage period and incubation period. Microbial activity in eggs stored for 7 d was significantly higher than in eggs stored for 14 d at the end of the storage. The lowest egg weight loss during storage was obtained in P15 treatment eggs stored for 7 d, whereas the highest egg weight loss was found in the treatment A after storage for 14 d. Although propolis treatment at 3 different doses was not effective on relative growth, only P15 decreased the BW at d 10, compared with the control. Hatchability in eggs stored for 14 d was significantly lower than in eggs stored for 7 d. No significant differences were observed for hatchability and embryonic mortality among propolis treatment groups. Propolis did not have a detrimental effect on hatchability, embryonic mortality, or BW gain. Our results indicate that propolis may be used to effectively reduce microbial activity on the surface of quail hatching eggs during storage and incubation without any detrimental effects on hatchability.Öğe The effects of starter culture on chemical composition, microbiological and sensory characteristics of Turkish kasar cheese during ripening(BLACKWELL PUBLISHING, 2007) Sert, Durmus; Ayar, Ahmet; Akin, NihatKasar cheese samples were produced from raw milk and starter culture- added pasteurized milk. Chemical, microbiological and organoleptic properties of kasar cheeses were analysed at certain times during the ripening periods ( on the 1st, 7th, 15th, 30th, 60th, 90th days). Generally, chemical parameters were not affected by starter culture. The pH, ripening index, water- soluble nitrogen and non- protein nitrogen did not show significant differences between the cheese samples. The addition of starter affected the microbiological quality of the cheeses. Starter culture- added kasar cheeses contained low levels of total aerobic mesophilic bacteria, moulds and yeasts, and coliforms, and achieved higher organoleptic scores than those of cheeses made from raw milk. The starter cultures contributed to acidity and microbial quality of the cheese. Kasar cheese samples were produced from raw milk and starter culture-added pasteurized milk. Chemical, microbiological and organoleptic properties of kasar cheeses were analysed at certain times during the ripening periods (on the 1st, 7th, 15th, 30th, 60th, 90th days). Generally, chemical parameters were not affected by starter culture. The pH, ripening index, water-soluble nitrogen and non-protein nitrogen did not show significant differences between the cheese samples. The addition of starter affected the microbiological quality of the cheeses. Starter culture-added kasar cheeses contained low levels of total aerobic mesophilic bacteria, moulds and yeasts, and coliforms, and achieved higher organoleptic scores than those of cheeses made from raw milk. The starter cultures contributed to acidity and microbial quality of the cheese.Öğe Effects of sunflower honey on the physicochemical, microbiological and sensory characteristics in set type yoghurt during refrigerated storage(WILEY-BLACKWELL PUBLISHING, INC, 2011) Sert, Durmus; Akin, Nihat; Dertli, EnesThe primary purpose of this research was to monitor the influence of sunflower honey addition (2%, 4% and 6% w/v) to yoghurt milk on survival of the microbial flora of yoghurt and the physicochemical and sensory characteristics during refrigerated storage for 4 weeks. The water activity decreased according to the addition of honey with higher concentrations in the storage period (4 degrees C). At the end of fermentation, pH values of yoghurt samples ranged between 4.33 (without honey) and 4.52 (addition of honey with 6%). The highest water holding capacity, consistency and the lowest brightness values were determined in the groups produced with 6% honey addition. The water holding capacity and a* (redness) values of the honey incorporated yoghurt samples increased during storage. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus values of the yoghurt with honey increased compared with the control group samples (P < 0.01). Addition of honey to yoghurt milk has affected the vitality of the characteristics starters in the incubation and storage time of the yoghurt samples (P < 0.01). Optimum sweetness was obtained with the samples containing 4% honey level.Öğe Effects of vacuum packing on eggshell microbial activity and egg quality in table eggs under different storage temperatures(WILEY, 2013) Aygun, Ali; Sert, DurmusBackround The aim of this study was to establish the effects of vacuum packing on eggshell microbial activity and egg quality traits in table eggs during 42 days of storage at 5 and 22 degrees C. Treatments were no vacuum packing (control) and vacuum packing (VP). Egg quality traits measured included egg weight loss, specific gravity, shell strength, albumen height, Haugh unit, yolk index, albumen pH, yolk pH, albumen colour and yolk colour. Results VP eggs maintained higher specific gravity, albumen height, Haugh unit and yolk index and lower egg weight loss, albumen pH and yolk pH compared with control eggs after 42 days at 22 degrees C. VP eggs had lower levels of total aerobic mesophilic bacteria, Salmonella spp., Staphylococcus spp. and moulds/yeasts than control eggs over the storage period at both 5 and 22 degrees C. However, VP eggs had a higher level of coliforms than control eggs after 42 days at 5 degrees C. Conclusion The results indicated that vacuum packing extended the egg shelf life to at least 42 days compared with control eggs at 5 and 22 degrees C.Öğe Fortification of set-type yoghurts with Elaeagnus angustifolia L. flours: Effects on physicochemical, textural, and microstructural characteristics(ELSEVIER SCIENCE BV, 2018) Ozturk, Hale Inci; Aydin, Sumeyye; Sozeri, Didem; Demirci, Talha; Sert, Durmus; Akin, NihatThe effect of peeled oleaster (Elaeagnus angustifolia L.) flour (PO) and unpeeled oleaster flour (UPO) in different levels (1% and 2%) on the quality parameters of set type yoghurt was investigated throughout 28 days of storage. Acidification kinetics, water holding capacity, syneresis level, textural characteristics and microstructure were firstly measured. Additionally, influence of oleaster flours on DPPH and ABTS(+) radical scavenging activity and total phenolic content of yoghurt samples was also assessed. Besides, all the products were subjected to sensorial preference test. Enrichment with 2% PO and UPO reduced fermentation time by 31 and 37 min, respectively. Addition of PO and UPO increased cohesiveness and the viscosity index, furthermore, syneresis decreased. Oleaster supplementation to yoghurt significantly increased scavenging activities of DPPH and ABTS radicals and the highest activities were determined in yoghurts fortified with 2% UPO. The results demonstrated that yoghurt with reduced syneresis, improved functional properties, and enhanced some textural characteristics can be achieved by a 2% UPO addition. Also, surprisingly yoghurts containing 2% UPO had similar consumer overall preference scores comparing to plain yoghurt.Öğe PEKMEZ-DAIRY DESSERTS FORTIFIED WITH SPRAY-DRIED DAIRY POWDERS: EFFECTS OF THE INTERACTION BETWEEN SKIM MILK POWDER, YOGHURT POWDER AND BUTTERMILK POWDER BY A MIXTURE DESIGN APPROACH(WILEY, 2009) Sert, Durmus; Yilmaz, Mustafa T.; Karakaya, Mustafa; Bayrak, EbruA mixture design approach was used to evaluate the interactions between skim milk powder (SMP), yoghurt powder (YP) and buttermilk powder (BMP) on rheological and sensory properties of dairy dessert mixture samples (DDMS). DDMS was prepared with pekmez powder, which was obtained by spray drying of pekmez, also known as concentrated grape molasses. Among the dairy powders, YP was the component that had the most effect on the viscosity of DDMS. The liking of the panelists was more prominent for the dairy dessert samples including the higher concentrations of YP. Optimum values of SMP, YP and BMP in the mixture were found to be 12-46%, 41-90% and 0-39%, respectively with respect to sensory properties. PRACTICAL APPLICATIONS The compositional properties of dairy powders can be changed by their usage at particular combinations, which could give rise to an improvement in their rheological and sensory properties. Such modifications would be of great economical importance to food industry. Dairy powders can be used to improve these properties when optimum combination levels of these dairy powders are taken into consideration. Therefore, information obtained in this study may be useful in practical industrial food product process monitoring and development.Öğe Physical, sensory and flow properties of wheat starch-dairy by-product spray-dried pekmez mixtures(BLACKWELL PUBLISHING, 2008) Sert, Durmus; Yilmaz, Mustafa T.; Karakaya, MustafaPekmez, also known as a concentrated grape juice, was spray dried in a laboratory-type pilot drying unit to obtain pekmez powder (PP). The flow characteristics of PP, wheat starch (WS) and some dairy by-products (whey powder, skim milk powder, calcium caseinate and sodium caseinate) systems as binary and ternary mixtures were studied. The empirical power law model fitted the apparent viscosity-rotational speed data. PP-dairy by-product and WS-dairy by-product mixed solutions exhibited a shear-thinning behavior at 21C with flow behavior index (n) values of 0.86 <= n <= 0.92 and 0.06 <= n <= 0.27, respectively. WS-dairy by-product mixed solutions showed high shear-thinning behavior with the highest consistency index (k = 25,425-180,599 mPa.s(n)). However, PP-WS and PP-WS-dairy by-product mixed solutions at the same temperature exhibited the shear-thickening behavior with flow behavior index (n) values of 1.05 <= n <= 1.18.Öğe Rheological and Sensory Properties of Spray Dried Pekmez Mixtures with Wheat Starch-Gum(TAYLOR & FRANCIS INC, 2009) Yilmaz, Mustafa T.; Sert, Durmus; Karakaya, MustafaPekmez, known also as grape molasses, was spray dried in the laboratory-type pilot drying unit to obtain pekmez powder. The flow characteristics of diluted pekmez powder (DPP), wheat starch (WS), and some hydrocolloids (locust bean gum, LBG; gum tragacanth, GT, and guar gum, GG) systems in double- or triple-mixed combinations were studied. The empirical power law model fitted the apparent viscosity-rotational speed data. DPP-gum and WS-gum mixed solutions exhibited a shear-thinning behaviour at 21C with flow behaviour index (n) values of 0.88 n 0.94 and 0.17 n 0.32, respectively. WS-gum mixed solutions showed high shear-thinning behaviour with the highest consistency index (k = 49.93-214.24 Pa sn). However, DPP-WS and DPP-WS-gum mixed solutions at the same temperature exhibited the shear-thickening behaviour with flow behaviour index (n) values of 1.02 n 1.07.Öğe A study on the occurrence of aflatoxin in raw milk due to feeds(WILEY, 2007) Ayar, Ahmet; Sert, Durmus; Con, Ahmet HilmiMilk and milk products are the most important group of food which carries aflatoxin to the people. Therefore, the existence of aflatoxin M-1 (AFM(1)) in milk is a potential risk for public health. AFM(1) existence in milk and milk products was found in studies performed in Turkey. In this study, aflatoxin contamination was detected in 48 raw milk and 48 feed samples. Milk and feed samples, in which the positive sample rate was determined as 24%, included different levels of aflatoxin. Altogether, 20 raw milk samples (41.67%) and 15 feed samples (31.25%) contained over the level of legal limits established by the Turkish Food Codex (TFC) and the European Communities (EC) regulation in positive samples. According to these results, the milk and feed samples collected from this area constitute a potential risk for public health. The most effective way of controlling aflatoxin M, in milk is to reduce the contamination of aflatoxin in raw milk and feed samples. Both the producers and the consumers, as well as the government, have important obligations on this subject.Öğe The trace metal levels in milk and dairy products consumed in middle Anatolia-Turkey(SPRINGER, 2009) Ayar, Ahmet; Sert, Durmus; Akin, NihatIn this study, aluminium (Al), lead (Pb), cadmium (Cd), selenium (Se) and arsenic (As) contents in milk and different dairy product samples were measured. Pb, Cd, As, Al and Se contents in the milk and different dairy products ranged from 0.054 mg/kg (milk powder)-1.100 mg/kg (Ka angstrom ar cheese), 0.009 mg/kg (whey powder and yogurt)-0.051 mg/kg (Tulum cheese), 0.010 mg/kg (whey powder)-0.146 mg/kg (butter), 2.848 mg/kg (ice cream)-8.778 (drained yogurt) and n.d. (ice cream, milk and whey powder, yogurt, ayran and Lor cheese)-0.434 mg/kg (Tulum cheese), respectively. The 75% of White and Ka angstrom ar cheeses, 50% of Lor and 12.5% of Tulum cheese samples contained higher Pb according to the legal limits established by the Turkish Food Codex and European Communities regulation and 12.5% of Tulum cheese sample contained Cd. It was concluded that Pb contents of milk and dairy products from this region might be highly hazardous to human.
