Sürdürülebilir Kalkınma Amaçları

• 3

• MakaleYalnız künye2016/r/bayburt/14462
  Rheological and Molecular Characterization of Modified Pectin from Sugar Beet Meal

  Yilmaz, Mustafa Tahsin; Muslu, Asli; Dertli, Enes; Toker, Omer Said

  The pectin was produced from sugar beet pulp, one of the significant waste of sugar industry, at optimum conditions (pH, time and temperature). Then, the modification was carried out using pectinase. FT-IR (Fourier transform infrared spectroscopy) and HPLC (high performance liquid chromatography) analysis were performed to characterize the differences between modified and unmodified pectin. FT -IR analysis revealed the specific regions of pectin and 1600-1800 cm-1 bands. Galacturonic acid content was analyzed by HPLC. The obtained results revealed that the modified pectin had higher galacturonic acid content. In addition, flow properties of the modified pectin was also determined. The flow characteristics of modified pectin was observed to change.

  AtıfWoS1

  İncele
• MakaleAçık Erişim2016Scopus SJRQ1/r/bayburt/12486
  Development of a fermented ice-cream as influenced by in situ exopolysaccharide production: Rheological, molecular, microstructural and sensory characterization

  Dertli, Enes; Toker, Omer S.; Durak, M. Zeki; Yilmaz, Mustafa T.; Tatlisu, Nevruz Berna; Sagdic, Osman; Cankurt, Hasan

  This study aimed to investigate the role of in situ exopolysaccharide (EPS) production by EPS+ Streptococcus thermophilus strains on physicochemical, rheological, molecular, microstructural and sensory properties of ice cream in order to develop a fermented and consequently functional ice-cream in which no stabilizers would be required in ice-cream production. For this purpose, the effect of EPS producing strains (control, strain 1, strain 2 and mixture) and fermentation conditions (fermentation temperature; 32, 37 and 42°C and time; 2, 3 and 4 h) on pH, S. thermophilus count, EPS amount, consistency coefficient (K), and apparent viscosity (η50) were investigated and optimized using single and multiple response optimization tools of response surface methodology. Optimization analyses indicated that functional ice-cream should be fermented with strain 1 or strain mixture at 40-42°C for 4 h in order to produce the most viscous ice-cream with maximum EPS content. Optimization analysis results also revealed that strain specific conditions appeared to be more effective factor on in situ EPS production amount, K and η50 parameters than did fermentation temperature and time. The rheological analysis of the ice-cream produced by EPS+ strains revealed its high viscous and pseudoplastic non-Newtonian fluid behavior, which demonstrates potential of S. thermophilus EPS as thickening and gelling agent in dairy industry. FTIR analysis proved that the EPS in ice-cream corresponded to a typical EPS, as revealed by the presence of carboxyl, hydroxyl and amide groups with additional α-glycosidic linkages. SEM studies demonstrated that it had a web-like compact microstructure with pores in ice-cream, revealing its application possibility in dairy products to improve their rheological properties.

  AtıfScopus86·WoS74·OpenAlex98

  İncele
• MakaleAçık Erişim2016Scopus SJRQ1/r/bayburt/12259
  Effects of in situ exopolysaccharide production and fermentation conditions on physicochemical, microbiological, textural and microstructural properties of Turkish-type fermented sausage (sucuk)

  Dertli, Enes; Yilmaz, Mustafa Tahsin; Tatlisu, Nevruz Berna; Toker, Omer Said; Cankurt, Hasan; Sagdic, Osman

  In this work, the role of in situ exopolysaccharide (EPS) production under different fermentation conditions on physicochemical, microbiological, textural and microstructural properties of sucuk was determined. For this purpose, the effect of EPS producing strains (control, strain 1, strain 2 and mixture) and fermentation conditions (fermentation temperature; 14, 16 and 18 °C and time; 8, 12 and 16 days) on physicochemical, microbiological, textural and microstructural properties were investigated using response surface methodology. In situ EPS production was observed to remarkably affect these properties while fermentation conditions were also seen to dominantly influence the physicochemical properties of sucuk, revealing that the ripening temperature appeared to be more determinant factor. EPS producing cultures enhanced the textural properties of sucuk which became harder, less adhesive and tougher. The microstructural analysis revealed the formation of web-like structure by in situ EPS production in sucuk mix during fermentation process. This study revealed the importance of in situ EPS production on final technological properties of sucuk.

  • 
  AtıfScopus48·WoS43·OpenAlex54

  İncele
• MakaleAçık Erişim2015Scopus SJRQ1/r/bayburt/13903
  Effect of in situ exopolysaccharide production on physicochemical, rheological, sensory, and microstructural properties of the yogurt drink ayran: An optimization study based on fermentation kinetics

  Yilmaz, M.T.; Dertli, E.; Toker, O.S.; Tatlisu, N.B.; Sagdic, O.; Arici, M.

  Exopolysaccharide (EPS)-producing starter cultures are preferred for the manufacture of fermented milk products to improve rheological and technological properties. However, no clear correlation exists between EPS production and the rheological and technological properties of fermented milk products such as the yogurt drink ayran. In this study, 4 different strain conditions (EPS- and EPS+ Streptococcus thermophilus strains) were tested as a function of incubation temperature (32, 37, or 42°C) and time (2, 3, or 4 h) to determine the effect of culture type and in situ EPS production on physicochemical, rheological, sensory, and microstructural properties of ayran. Furthermore, we assessed the effect of fermentation conditions on amounts of EPS production by different EPS-producing strains during ayran production. A multifactorial design of response surface methodology was used to model linear, interaction, and quadratic effects of these variables on steady shear rheological properties of ayran samples and in situ EPS production levels. The physicochemical and microbiological characteristics of ayran samples altered depending on incubation conditions and strain selection. Steady shear tests showed that ayran samples inoculated with EPS+ strains exhibited pseudoplastic flow behavior. Production of ayran with EPS- strain (control sample) resulted in the lowest apparent viscosity values (η50), whereas those produced with the combination of 2 EPS+ strains yielded ayran with notably increased η50 values. We concluded that incubation time was the variable with the greatest effect on η50, consistency coefficient (K), and flow behavior index (n) values. In situ EPS production was also affected by these conditions during ayran fermentation in which strain-specific metabolism conditions were found to be the most important factor for EPS production. In addition, these findings correlated the amount of in situ EPS produced with the rheological properties of ayran. Scanning electron microscopy images of the samples showed differences in structural features, revealing a prominent network strand structure in the ayran samples inoculated with the admixture of 2 EPS-producing strains incubated at 37°C for 3 h. These results provide useful information for large-scale production of ayran by the dairy industry.

  • 
  AtıfScopus79·WoS65·OpenAlex92

  İncele
• MakaleYalnız künye2015Scopus SJRQ1/r/bayburt/13663
  Thermal loop test to determine structural changes and thermal stability of creamed honey: Rheological characterization

  Karasu, Salih; Toker, Omer Said; Yilmaz, Mustafa Tahsin; Karaman, Safa; Dertli, Enes

  This study was the first attempt to understand if thermal stability of any food product during storage could be determined. In this respect, a novel method, namely, the thermal loop test was used to determine structural changes and thermal stability of creamed honey in this study. The novelty of this method was that thermal stability of a product is tested within a number of thermal cycles over a determined range of temperature. Creamed honey was characterized in terms of physicochemical, thermomechanical and rheological properties. It showed non-Newtonian thixotropic behavior at all temperature levels (10, 25 and 40 °C). Time-dependent flow behavior was successfully defined by Weltman and second order structural models. Hysteresis loop area depended on temperature and decreased with increase in temperature. Creamed honey had liquid-like structure, showing that it had more pronounced viscous nature than elastic nature (G″ > G′). Temperature sweep tests were conducted to determine temperature dependency of η50, G′ and G″ values using Arrhenius equation. These test results confirmed the thermal stability test results, revealing that thermal loop test can be an accurate method to determine thermal stability of similar food products, as a new information. Relative structural index value (Δ) increased with number of thermal loop, suggesting that creamed honey had low thermal stability and showed a great structural change by the thermal stress applied between 5 °C and 50 °C. These results suggest that crystallized honey be abstained from large temperature fluctuations to avoid from irreversible changes in rheological characters; thus, to maintain spreadability.

  AtıfScopus45·WoS43·OpenAlex47

  İncele
• MakaleAçık Erişim2014Scopus SJRQ1/r/bayburt/12316
  Steady, dynamic and creep rheological analysis as a novel approach to detect honey adulteration by fructose and saccharose syrups: Correlations with HPLC-RID results

  Yilmaz, Mustafa Tahsin; Tatlisu, Nevruz Berna; Toker, Omer Said; Karaman, Safa; Dertli, Enes; Sagdic, Osman; Arici, Muhammet

  In this study, natural honey was adulterated with the addition of adulterants, namely saccharose and fructose syrups at a ratio of 0%, 10%, 20%, 30%, 40% and 50% by weight. Steady, dynamic and creep tests were conducted, revealing that the changes in the flow, viscoelastic and creep behavior of natural honey were clear and remarkable. Syrup addition decreased viscosity (η), storage (G') and loss modulus (G″) values of the control honey samples. Deformation represented by the compliance (J(t)) values was more prominent in the adulterated honey samples. In addition, HPLC-RID analysis was conducted to determine major sugar composition of the adulterated samples. Pearson's correlation test indicated that there were significant (P<0.05; 0.01) correlations between sugar composition and rheology parameters, η (viscosity), K″, K* (intercepts for G″ and complex modulus (G*), respectively) and η0 (viscosity of Maxwell dashpot), suggesting that K', K″, K* and η0 could be prominent indicators for presence of saccharose or fructose syrups added in natural honey within the studied concentration levels. These results suggested that use of steady, dynamic and creep analysis would be a novel and potential approach to detect honey adulteration by fructose and saccharose syrups.

  • 
  AtıfScopus81·WoS72·OpenAlex80

  İncele