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Öğe Angiotensin-converting enzyme inhibitory and starter culture activities in probiotic yoghurt: Effect of sodium–calcium caseinate and whey protein concentrate(Blackwell Publishing Ltd, 2018) Akalin A.S.; Unal G.; Dinkci N.This study investigated the effect of fortification with sodium–calcium caseinate (SCaCN), whey protein concentrate (WPC) or a blend of those ingredients on some properties of probiotic yoghurt. At the beginning of the storage, the highest angiotensin-converting enzyme inhibitory activity (ACEI %) was obtained from yoghurts with SCaCN. However, the levels of proteolytic and ACEI activities were highest in WPC-supplemented yoghurt after 14 and 28 days. The highest Bifidobacterium animalis subsp. lactis Bb12 viability was obtained in yoghurts with WPC or the SCaCN–WPC blend. A gradual increase in lactic acid was also obtained in the yoghurts supplemented with WPC or with the SCaCN–WPC blend; there was no increase in acetic acid. © 2017 Society of Dairy TechnologyÖğe Antioxidant activity of probiotic yoghurt fortified with milk protein based ingredients(2013) Unal G.; El S.N.; Akalin A.S.; Dinkci N.The effect of the fortification with sodium calcium caseinate (SCC) and whey protein concentrate (WPC) on antioxidant activity of probiotic yoghurt, containing Bifidobacterium lactis Bb12, was investigated. Probiotic yoghurt fortified with WPC had a higher DPPH (2,2,-diphenyl-1-picrylhydrazyl) radical-scavenging activity when compared to that fortified with SCC. In Fe 2+ chelating activity method, probiotic yoghurts fortified with SCC and a blend of SCC-WPC showed greatest chelating activity by 30 and 60 min. There were no significant differences in the H2O2 scavenging activity among samples except control yoghurt, which showed the lowest activity, at a concentration of 0.2 g/mL.Öğe Concentrations of riboflavin in dairy products and the effect of refrigerated storage on its changes in UHT-milks(2003) Akalin A.S.; Gönç S.; Dinkçi N.Riboflavin, a water-soluble, light-sensitive vitamin, was determined in dairy products from Turkish supermarkets. High-performance liquid chromatography was used with a reversed-phase C18 column and ultraviolet-visible detection. A solvent system of water-methanol (70:30 v/v) with acetic acid (1,5 ml) in water (1 l) and a flow rate of 0.5 ml min -1 gave the most appropriate separation of riboflavin at 270 nm. The linearity, recovery and reproducibility of the method were satisfactory. The riboflavin content ranged from 1.391 to 1.159 mg l-1 in pasteurized milks, from 1.532 to 1.302 mg l-1 in UHT milks, from 1.662 to 1.302 mg kg-1 in yoghurts, and from 3.681 to 1.479 mg kg-1 in pickled White cheeses. When the opened containers of UHT milks were stored in a refrigerator at 5°C, in the dark, the loss of riboflavin ranged from 1.84 to 6.05% of the initial values.Öğe Determination of organic acids in commercial cheeses by high performance liquid chromatography(1997) Akalin A.S.; Kinik Ö.; Gönç S.Commercial cheese samples were analyzed for the presence of organic acids using high performance liquid chromatography. A reverse-phase C18 column at room temperature, a mobile phase of 0.5 % (w/v) buffer (NH4)2HPO4 at pH 2.24 (with H3PO4) and 0.4% (v/v) acetonitrile, UV detector at 214 nm and 0.3 ml/min flow rate were utilized. Formic, pyruvic, lactic, acetic, orotic, citric, uric, propionic and butyric acids were quantitated for White, Feta, Kasar, canned Tulum and skinned Tulum cheeses. Recoveries >86.3% were observed for all acids. Organic acid contents of Kasar cheeses were generally found to be higher than the others.Öğe Effect of supplementation with green and black tea on microbiological characteristics, antimicrobial and antioxidant activities of drinking Yoghurt [Yeşil ve siyah çay ilavesinin içilebilir yoğurdun mikrobiyolojik Özellikleri ile antimikrobiyal ve antioksidan aktivitesi Üzerine etkisi](Ankara University, 2018) Ünal G.; Karagözlü C.; Kinik Ö.; Akan E.; Akalin A.S.The influence of supplementation with green and black tea on microbiological properties, antimicrobial and antioxidant activities of drinking yoghurt were investigated during 21 days of storage. The samples supplemented with 2% either green or black tea had higher viable counts of both yoghurt starter bacteria than those of infused by the ratio of 4%. Both green and black tea extracts showed antimicrobial activity on E. coli, B. cereus, S. aureus and C. albicans however this effect was detected higher in samples containing green tea. The samples added green tea extract had the highest DPPH scavenging activity when compared to those supplemented with black tea extract throughout the storage. Green tea had a superior effect than black tea in terms of total phenolic content of drinking yoghurt samples. © Ankara Üniversitesi Ziraat Fakültesi.Öğe Effect of supplementation with green and black tea on microbiological characteristics, antimicrobial and antioxidant activities of drinking Yoghurt [Yeşil ve siyah çay ilavesinin içilebilir yoğurdun mikrobiyolojik Özellikleri ile antimikrobiyal ve antioksidan aktivitesi Üzerine etkisi](Ankara University, 2018) Ünal G.; Karagözlü C.; Kinik Ö.; Akan E.; Akalin A.S.The influence of supplementation with green and black tea on microbiological properties, antimicrobial and antioxidant activities of drinking yoghurt were investigated during 21 days of storage. The samples supplemented with 2% either green or black tea had higher viable counts of both yoghurt starter bacteria than those of infused by the ratio of 4%. Both green and black tea extracts showed antimicrobial activity on E. coli, B. cereus, S. aureus and C. albicans however this effect was detected higher in samples containing green tea. The samples added green tea extract had the highest DPPH scavenging activity when compared to those supplemented with black tea extract throughout the storage. Green tea had a superior effect than black tea in terms of total phenolic content of drinking yoghurt samples. © Ankara Üniversitesi Ziraat Fakültesi.Öğe Effects of inulin and oligofructose on the rheological characteristics and probiotic culture survival in low-fat probiotic ice cream(2008) Akalin A.S.; Erişir D.The effects of supplementation of oligofructose or inulin on the rheological characteristics and survival of Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 in low-fat ice cream stored at -18°C for 90 d were studied. Addition of oligofructose or inulin to ice cream mix significantly increased apparent viscosity and overrun and developed the melting properties in ice cream during storage (P < 0.05). However, the highest increase in firmness, the lowest change in melting properties, and the longest 1st dripping time were obtained in probiotic ice cream containing inulin (P < 0.05). Some textural properties have also improved especially by the end of storage. Freezing process caused a significant decrease in the viability of Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 (P < 0.05). Oligofructose significantly improved the viability of L. acidophilus La-5 and B. animalis Bb-12 in ice cream mix (P < 0.05). Although the viable numbers for both bacteria decreased throughout the storage, the minimum level of 10 6 CFU/g was maintained for B. animalis Bb-12 in only ice cream with oligofructose during storage. © 2008 Institute of Food Technologists.Öğe Fatty acid and conjugated linoleic acid profiles of infant formulas through direct transesterification of acyl lipids(2007) Tokuşoglu Ö.; Durucasu I.; Akalin A.S.; Serin E.; Akşit S.Fatty acid (FA) values, including C8:0, C10:0, C12:0, C13:0, C14:0, C16:0, C18:0, C18:l t, C18:l c, C18:2, C18:2 CLA, C20:0, C18:3 and C22:0, in sixteen infant formulas were determined through direct transesterification of acyl lipids with sodium methoxide by capillary gas chromatography. Total FA values ranged from 250.25-256.06 mg/g sample and the conjugated linoleic acid (CLA) (cis-9, trans-11 octadecadienoic acid) values were 1.41-2.02 mg/g sample (p<0.01) in the infant formulas. The total saturated fatty acid, monounsaturated fatty acid and polyunsaturated fatty acid values were also obtained. The C18:3 (linolenic acid (n-3)) values were 0.63-0.88 mg/g sample, whereas the C18:2 (linoleic acid (n-6)) values ranged from 35.64-35.82 mg/g sample. FA standard mix including CLA had linear calibration curves through the origin (R2 = 0.9999). The precision of the analytical method was (using C13:0, methyl tridecanoate, as internal standard) within the 95% confidence limits and the mean recoveries determined for individual fatty acids in infant formulas varied from 99.8 to 100%.Öğe Importance of dairy products in metabolic syndrome-cardiovascular disease, insulin resistance and diabetes, and hypertension (Part 2)(2008) Ünal G.; Akalin A.S.; Akbulut N.The metabolic syndrome is a group of metabolic disorders, namely obesity, glucose intolerance, hypertension and hypercholesterolemia. Several epidemiological studies have indicated that the consumption of dairy products, especially low-fat products, was inversely associated with body mass index (BMI), blood pressure, plasma lipids, insulin resistance and type-2 diabetes. Many dairy components may contribute to these beneficial effects. Although there is a certain focus on calcium in literature, it has not been cleared up until now which components) of milk and dairy products contribute to the positive effects. Whey and whey protein derived peptides have been shown to have a hypotensive effect. Positive effect of the consumption of dairy products on coronary heart disease and impaired glucose tolerance, needs further confirmation.Öğe The influence of milk supplementation on the microbiological stability and textural characteristics of fermented milk(2010) Akalin A.S.; Ünal G.In the present work, the effect of milk supplementation on the viability of probiotics and textural characteristics of fermented milk was studied. Three powders, namely skim milk powder (SMP) as a control, fructooligosaccharides (FOS), and whey protein concentrate (WPC) were tested as supplements. Milk was fermented by a commercial starter culture (ABT-7) containing Lactobacillus acidophilus La 5, Bifidobacterium animalis subs. lactis Bb 12, and Streptococcus thermophilus. S. thermophilus was found to be the most numerous starter culture in all samples, and in general the addition of FOS and WPC did not affect its viability significantly (p>0.05). The viability of L. acidophilus increased by supplementation with FOS when compared to WPC supplementation until the 21st day. However, the viable counts of bifidobacteria were maintained above 7 log cfu g-1 in only WPC-supplemented fermented milks during storage. In the presence of WPC, apparent viscosity and gel firmness decreased in comparison with that of SMP (p<0.05).Öğe Influence of packaging conditions on the textural and sensory characteristics, microstructure and color of industrially produced turkish white cheese during ripening(2010) Akalin A.S.; Karaman A.D.A full-fat Turkish white cheese was manufactured on an industrial scale and then packaged in a polystyrene container with brine containing 12% salt or a plastic pouch sealed under vacuum, before ripening for 90 days. With regard to textural characteristics, packaging in a plastic pouch resulted in cheeses with significantly higher hardness and cohesiveness (P < 0.05). Scanning electron micrographs showed a more compact and denser protein matrix for the cheese packed in the plastic pouch. Much yellowness was also obtained in cheeses with the plastic pouch (P < 0.05). The experimental cheeses had a similar sensory characteristics in the first 45 days (P > 0.05), but the taste and odor scores decreased in the cheeses packaged with the plastic pouch (P < 0.05) in the 60th and 90th days. © 2010 Wiley Periodicals, Inc.Öğe Influence of packaging systems on the biochemical characteristics and volatile compounds of industrially produced turkish white cheese*(2011) Akalin A.S.; Karaman A.D.Full-fat Turkish white cheese was manufactured in an industrial scale and ripened for 90 days after packaging in polystyrene container with brine containing 12% salt or cryovac plastic material under vacuum. White cheese packaged with cryovac container had higher contents of total solids, milk fat, water-soluble nitrogen and lactic acid and lower contents of salt and ash than the cheese packaged in polystyrene container during ripening (P<0.05). The ripening index and the counts of lactococci and lactobacilli were also higher with cryovac container (P<0.05). With regard to volatile compounds, a total of 40 components were identified: alcohols (5), aldehydes (3), ketones (7), esters (4), volatile acids (10), hydrocarbons (8) and other compounds (3). Volatile acids were the main components of both Turkish white cheeses. The contents of hexanoic and butanoic acids, dominant acids of cheese in cryovac container, were significantly higher when compared to the cheese in polystyrene cup (P<0.05). PRACTICAL APPLICATIONS: Turkish white cheese was generally ripened for up to 3 months in brine and marketed in can or plastic package containing brine. Recently, cheese molds have been packaged in cryovac container without brine. The chemical composition of cheese on the contents of dry matter, fat, water-soluble nitrogen, salt, lactic acid and the counts of starter bacteria were influenced by packaging system. Ripening index and dominant volatile compounds of cheese were also affected by packaging in polystyrene container with brine containing 12% salt or cryovac plastic material under vacuum. © 2010 Wiley Periodicals, Inc.Öğe Influence of Spirulina platensis biomass on microbiological viability in traditional and probiotic yogurts during refrigerated storage(2009) Akalin A.S.; Ünal G.; Dalay M.C.The effect of adding Spirulina platensis on the viability of a yogurt starter and Bifidobacterium animalis was assessed during 28 days of refrigerated storage. Four types of yogurts were manufactured: The control yogurt; yogurt containing S. platensis; yogurt containing B. animalis; yogurt containing S. platensis and B. animalis. On average, the survival rate of Streptococcus salivarius ssp. thermophilus was better than those of both Lactobacillus delbrueckii ssp. bulgaricus and B. anima- lis. S. platensis biomass significantly decreased the viability of S. thermophil- us but increased the viable cell counts of L. bulgaricus in both traditional and probiotic yogurts. The stability of B. an- imalis, on average, remained statistically constant throughout the refrigerated storage period in probiotic algal yogurt compared to probiotic non-algal yogurt. It was also shown that probiotic algal yogurt has a shelf-life of one month with a viable Bifidobacterium cell count of at least 6 log cfu g1.Öğe Influence of Yogurt and Acidophilus Yogurt on Serum Cholesterol Levels in Mice(American Dairy Science Association, 1997) Akalin A.S.; Gönç S.; Düzel S.The effects of yogurt and acidophilus yogurt on the weight gain, serum cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, triglycerides, and the numbers of fecal lactobacilli and coliforms were investigated in mice assigned to three dietary treatments for 56 d: 1) commercial rodent chow and water (control), 2) commercial rodent chow and yogurt made from milk inoculated with a 3% (vol/vol) liquid culture of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus (yogurt), and 3) commercial rodent chow plus yogurt made from milk inoculated with a 0.01% (wt/vol) freeze-dried culture of Streptococcus thermophilus plus Lactobacillus acidophilus. The weight gains of mice receiving yogurt or acidophilus yogurt were higher than those of the mice in the control group. The mean values for serum cholesterol concentrations and LDL cholesterol concentrations were significantly decreased when acidophilus yogurt was fed on d 28 and 56. High density lipoprotein cholesterol and triglycerides were not affected by yogurt or acidophilus yogurt. The highest number of fecal lactobacilli was found in mice receiving acidophilus yogurt, and the number of fecal coliforms of that group was also lower than in the other two groups.Öğe Lactulose and 5-HMF contents in market milks(1997) Akalin A.S.; Gönç S.The lactulose and HMF contents in market milks were analyzed by gas chromatographic and colorimetric methods, respectively. UHT milk samples, directly or indirectly heat-treated, were also examined for lactulose and HMF during a period of 120 d storage in 4-week intervals at room temperature or 30°C. The gas chromatographic method was evaluated for precision and accuracy using phenyl-ß-glucoside as internal standard. The mean recovery was found to be 99.1 %. The mean lactulose content of the market milks determined was 1.2-1.9 mg/100 ml in pasteurized milks and 7.6-45.4 mg/100 ml in UHT milks and were found to be within the limits considered acceptable. The HMF contents of UHT milks varied between 5.2 and 15.1 µmol/l. The lactulose content has been shown to be useful in distinguishing pasteurized, directly heated UHT and indirectly heated UHT milks. The production dates of UHT milks were found to be important in definition of the lactulose level because of the increase of lactulose during the storage at 30°C.Öğe Liquid chromatographic detection of ?-, ?-, ?-tocopherols in infant formulas(2004) Akalin A.S.; Tokuşoglu Ö.Simultaneous determination of ?-tocopherol, ?-tocopherol and ?-tocopherol by reversed-phase liquid chromatography (RP-HPLC) with UV detection in various infant milk formulas sold in Turkey was performed. Analytical method parameters confirmed the quality of the method. Tocopherol isomers in 15 infant formulas ranged from 8.73±0.09 to 27.02±0.06 mg ?-tocopherol in 100 g-1, from 1.67±0.04 to 7.28±0.10 mg ?-tocopherol in 100 g-1; from 0.87±0.05 to 1.81±0.03 mg ?-tocopherol in 100 g -1.Öğe Liquid chromatographic determination of thiamin in dairy products(2004) Akalin A.S.; Gönç S.; Dinkçi N.Concentrations of thiamin were determined in pasteurized and UHT-sterilized milks, yoghurt and kefir samples by high-performance liquid chromatography using a reversed-phase C-18 column connected to fluorescence detector. The linearity, recovery and reproducibility of the method were satisfactory. The thiamin content ranged from 0. 305± 0.02 to 0.252±0.03 mg/l in market milks. Yoghurt samples had higher concentration of thiamin (0.355±0.04 and 0.404± 0.02 mg/l) than values found in market milks. The least thiamin content was found in kefir (0.175±0.03 mg/l) among the samples analyzed. © 2004 Taylor & Francis Ltd.Öğe Microstructural, textural, and sensory characteristics of probiotic yogurts fortified with sodium calcium caseinate or whey protein concentrate(2012) Akalin A.S.; Unal G.; Dinkci N.; Hayaloglu A.A.The influence of milk protein-based ingredients on the textural characteristics, sensory properties, and microstructure of probiotic yogurt during a refrigerated storage period of 28 d was studied. Milk was fortified with 2% (wt/vol) skim milk powder as control, 2% (wt/vol) sodium calcium caseinate (SCaCN), 2% (wt/vol) whey protein concentrate (WPC) or a blend of 1% (wt/vol) SCaCNand 1% (wt/vol) WPC. A commercial yogurt starter culture and Bifidobacterium lactis Bb12 as probiotic bacteria were used for the production. The fortification with SCaCN improved the firmness and adhesiveness. Higher values of viscosity were also obtained in probiotic yogurts with SCaCN during storage. However, WPC enhanced water-holding capacity more than the caseinate. Addition of SCaCN resulted in a coarse, smooth, and more compact protein network; however, WPC gave finer and bunched structures in the scanning electron microscopy micrographs. The use of SCaCN decreased texture scores in probiotic yogurt; probably due to the lower water-holding capacity and higher syneresis values in the caseinate-added yogurt sample. Therefore, the textural characteristics of probiotic yogurts improved depending on the ingredient variety. © 2012 American Dairy Science Association.Öğe Microstructure of industrially produced reduced and low fat Turkish white cheese as influenced by the homogenization of cream(2012) Karaman A.D.; Benli M.; Akalin A.S.The microstructure and fat globule distribution of reduced and low fat Turkish white cheese were evaluated. Reduced and low fat cheeses were manufactured from 1.5% and 0.75% fat milk respectively which were standardized unhomogenized and homogenized cream in a dairy plant. Homogenized and non-homogenized creams and cheese whey were analyzed for fat globule distribution and cheese samples were also analyzed for microstructure characteristics. According to the results, the homogenization of cream decreased the size of fat globules; and showed that a large number of fat particles were dispersed in the in matrix and improved the lubrication of cheese microstructure. According to the micrographs for the fat, which was not removed, they exhibited a more extended matrix with a few small fat globules compared to the defatted micrographs. Homogenization of cream produces small fat globules and unclustured fat globules were found in the resulting whey. These results are important for dairy processors for using cream homogenization as a processing tool at the industrial level.Öğe A rapid high performance liquid chromatographic detection of furosine (?-N-2-furoylmethyl-L-lysine) in pasteurized and UHT milks(2004) Tokuşoglu Ö.; Akalin A.S.; Unal M.K.Furosine, generated from the acid hydrolysis of the amadori compound during the early Maillard reaction, is a suitable indicator of the effect of heating treatments on milk quality. Furosine content in pasteurized and UHT milks marketed in Turkey was detected using ion-pair reversed-phase liquid chromatography (RP-HPLC). Calibration study (R2 = 0.9999), analytical method validation and recovery studies (y = 5.315 x + 0.043 (R2 = 0.9998)) gave satisfactory results A wide range of furosine content was found in UHT milks (49.68 ± 0.10 to 213.38 ± 0.07 mg 100 g-1 protein) depending on the heat-treatment intensity. Pasteurized milks had lower content of furosine (3.79 ± 0.01 and 5.88 ± 0.02 mg 100 g -1 protein). The method provides rapid, reproducible and accurate determination of this amadori compound in milk and dairy products and can be utilized as one of the most commonly used quality marker in dairy industry.
