Sürdürülebilir Kalkınma Amaçları

• 2

• MakaleAçık Erişim2019Scopus SJRQ1/r/bayburt/12127
  Non-linear rheological (LAOS) behavior of sourdough-based dough

  Yildirim-Mavis, Cigdem; Yilmaz, Mustafa Tahsin; Dertli, Enes; Arici, Muhammet; Ozmen, Duygu

  During processing, wheat dough is known to undergo large deformation led by mixing and fermentation processes. This deformation is much more pronounced when sourdough is used in the recipe of wheat dough whose gluten is considerably hydrolyzed during sourdough fermentation. This causes deeper effects on rheological properties and shelf life of bakery products. Traditional small amplitude oscillatory tests do not enable us to comprehend the viscoelasticity under large deformations. In this respect, large amplitude oscillatory shear (LAOS) tests are useful for accurate characterization of the non-linear mechanical response. This study, therefore, is undertaken to investigate the non-linear mechanical response of dough prepared with different amounts of sourdough (0, 10, 20 30 and 40%) in a strain values ranging from 0.005 to 200% (frequency at 10 rad/s). As a result, sourdough was determined to have considerable effects on the non-linear viscoelastic response of dough. Strain-stiffening and shear-thinning behaviors were considerably influenced by sourdough incorporation and the dough started to show strain-softening and lowered shear-thinning behavior after giving a peak around at 100% strain due to the onset of the breakdown of the gluten network and suspension of starch matrix as consequence of the metabolic activity of the starter culture (Lactobacillus brevis E25) used in the preparation of sourdough. The physicochemical (pH and TTA), microbiological properties (LAB count) and extensographic properties were also shown to support the LAOS results. LAOS tests could be effectively and clearly used to reveal the effect of processing conditions (sourdough content and deformation by large strain amplitude) on the non-linear mechanical response of wheat dough.

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  AtıfScopus49·WoS46·OpenAlex46

  İncele
• MakaleAçık Erişim2015Scopus SJRQ1/r/bayburt/13911
  The effect of starch modification and concentration on steady-state and dynamic rheology of meat emulsions

  Genccelep, Huseyin; Saricaoglu, Furkan Turker; Anil, Munir; Agar, Berrin; Turhan, Sadettin

  In this study, the effect of starch modification (NPS, native potato starch; AMS, acid modified starch; DMS, dextrinized modified starch; PGS, pre-gelatinized modified starch) and its concentrations (1, 2, 4wt%) on steady-state and dynamic rheological properties of meat emulsions were determined. Water-oil binding capacity and intrinsic viscosity of potato starch increased up to 5.07-0.90g/g, and 14.98mL/g, respectively, after modifying with pre-gelatinization method. The particle size of starches as average mean diameter ranged between 44.19μm and 293.06μm. The maximum solubility was obtained from DMS after heat treatment at 70°C being 48.22%, which means an increase about 3.06-fold in solubility as compared with NPS. The Ostwald-de Waele model was successfully used to describe the flow properties of meat emulsions (R2>0.961). While starch types did not affect the K values of emulsions (p>0.05), starch concentrations did (p<0.01). All studied emulsions exhibited non-Newtonian, pseudoplastic behavior since n values were lower than 1. Emulsion systems were characterized as weak gel-like macromolecular dispersions with storage modulus (G') much greater than loss modulus (G″). A modified Cox-Merz rule was applied by multiplying angular frequency with shift factors (αSF). Frequency dependence of complex modulus (G*) was studied to measure the strength of cross-linking protein network of emulsion systems by calculating a constant order of relaxation function (α) and concentration dependent stiffness parameter (Aα). It was concluded that PGS addition improved rheological properties of meat emulsions due to higher solubility, particle size, intrinsic viscosity, water-oil binding capacity than NPS.

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  AtıfScopus92·WoS77·OpenAlex92

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