Şenol İbanoğlu

Effect of fermented/germinated cowpea flour addition on the rheological and baking properties of wheat flour

There is a growing interest in fortifying wheat flour with high lysine material, such as cowpea flour, to improve the essential amino acid balance of baked food products. The use of cowpeas as a food source has not been utilised fully, especially in developed countries. In this research, wheat flour in a standard bread formulation was partially replaced with cowpea flour, germinated cowpea flour and fermented cowpea flour at levels of 5%, 10%, 15% and 20% (wt/wt). Composite flours were analysed for ash, protein, gluten contents and α-amylase activity as well as colour, farinograph and extensograph characteristics. Bread baked from composite flours was analysed for loaf volume and weight, texture, crumb-grain structure and colour. Increasing levels of cowpea flour in the blends resulted in changed flour characteristics such as ash and protein contents and colour. It also changed farinograph and extensograph characteristics, mainly by increased water absorption. Incorporation of cowpea flour exerted a certain volume depressing effect on the bread and gave a compact structure at higher substitution levels. Overall acceptable results were obtained based on characteristics of control bread.

Foaming behaviour of liquorice (Glycyrrhiza glabra) extract

Abstract The foaming behaviour of liquorice extract was investigated using response surface methodology with concentration (0.1–0.3 w/v%) and whipping time (5–25 s) being the independent variables. A first-order kinetics was applied for the kinetic analyses of the foam collapse and foam decay rate constants were calculated. Regression equations for predicting overrun ( O ) and foam decay rate constant ( k ) were developed. Results suggest that concentration had a significant effect ( P ⩽0.01) on overrun and foam stability. The overrun increased with concentration and whipping time. However, the effect of whipping time on O was less pronounced. Foam stability was enhanced with the increase in concentration. The foam decay rate was observed to be mainly dependent on the concentration of sample ( P ⩽0.01) and decreased with the increase in concentration. The effect of whipping time on foam stability was observed to be insignificant ( P ⩽0.01) compared with concentration. The magnitude of changes with whipping time were observed to be more pronounced for the overrun than for the stability of liquorice extract foam.

Rheological characterization of some traditional Turkish soups

Abstract The rheological behaviour of three traditional Turkish soups was studied at different temperatures (15–70 °C), using a Brookfield viscometer. Results showed that an increase in shear rate resulted in a decrease in apparent viscosity, suggesting pseudoplastic behaviour with flow indices, n, between 0.30 and 0.43. Viscosity decreased with temperature and was described by the Arrhenius equation with activation energies between 15039 and 20160 kJ mol−1.

Effect of cooking on the drying behaviour of tarhana dough, a wheat flour–yoghurt mixture

Abstract Drying behaviour of tarhana dough before and after simmering at atmospheric pressure for 10 min was studied by changing the drying temperature (60–80 °C) and sample thickness (1–6 mm). The cooking process accelerated the drying process possibly due to increased porosity of dough by starch gelatinization. Ficks equation was used to calculate the diffusion coefficient for water ( D eff ) at different sample thicknesses. An increase in D eff values was observed at increased sample thickness for both normal and cooked dough. The D eff values for cooked dough were higher when compared to normal dough. Activation energies were calculated using an Arrhenius type equation to determine the effect of drying temperature on D eff values. It was found that D eff values are more sensitive to changes in drying temperature during drying of normal tarhana dough than during that of a cooked dough cooked, suggested by higher activation energies for normal tarhana dough.

Foaming behaviour of EDTA-treated α-lactalbumin

The foaming properties of partially denatured α-lactalbumin was investigated. The partially denatured state was produced by removing bound Ca2+ by treatment with ethylenediaminetetraacetic acid (EDTA) at pH 8.0 and 25°C. Surface tension measurements showed that partially denatured α-lactalbumin unfolds easily at liquid interfaces compared with the native protein. The results of foam volume and stability measurements were consistent with the results of surface tension measurements. In the presence of EDTA a considerable amount of foam was obtained at low concentrations, such as 0.1 mg/ml, and the foam stability was improved. This indicates the importance of the protein structure on the adsorption of molecules at liquid interfaces. The presence of Ca2+ also resulted in an increase in the foamability and foam stability of α-lactalbumin compared with native protein, due to the saturation of the surface charges. This shows the binding affinity of protein to Ca2+. The investigation of the effect of Ca2+ on the surface behaviour of β-lactoglobulin, another whey protein, also showed an improvement in the foaming properties of protein.

Influence of extrusion variables on the protein in vitro digestibility and protein solubility of extruded soy tarhana

Tarhana, supplemented with 150 g kg−1 full-fat soy flour, was extruded at different extrusion conditions (barrel temperature: 80–120°C; screw speed: 100–300 rpm; feed rate: 10–20 kg h−1 ) using a twin-screw extruder. The effect of extrusion conditions on the in vitro digestibility (PD) of the protein and protein solubility (PS) was investigated using response surface methodology. Regression equations for predicting PD and PS were developed. While the barrel temperature had a significant effect on PD (P <0.1), feed rate was the most significant variable on PS of the samples (P<0.05). Since the protein solubility should be high for the instant properties of extruded soy tarhana soup, it is suggested that soy tarhana should be extruded at low feed rates (ie high residence times) while high barrel temperatures should be achieved for the inactivation of antinutritional factors present in the soy flour. © 1999 Society of Chemical Industry

Structure, Physico-chemical and Microbiological Properties of Ozone-oxidized Wheat, Corn, Potato and Rice Starches

A limited number of studies have been conducted on the effects of ozone use on cereal and its components. Starch, an important natural macromolecule, is an essential component of cereals. In present study, the effects of ozone on the structure, physico-chemical and microbiological properties of wheat, corn, potato and rice starches were investigated. Wheat starch, corn starch, potato starch and rice starch water mixtures were prepared in the ratio of 1:9 (dry sample to water ratio) and treated with ozone at a rate of 60 g/h for 1 hour, while unozonated samples were used as controls. Light microscopy represented that the structures of corn and potato starch samples were affected by 1 hr ozonation rather than the structures of wheat and rice starch samples. Colour of ozone-oxidized wheat, corn and potato starch samples could meet the consumer preference due to the higher lightness, higher whiteness and lower chroma value. However, high chroma, high yellownes and low whiteness values of ozonated rice starch is not adequate for consumer desire. Microbiological analysis showed that 1 hr ozonation reduced the total bacteria and mould/yeast counts significantly for all wheat, corn, potato and rice starch samples (P ＜ 0.05) due to most probably the reduced pH of samples. Ozonation can be an alternative modification technique, but further research is needed to understand the certain benefits and limitations of ozone applications on starch oxidation for human safety and health.

Effect of milled lupin products and transglutaminase on some properties of noodle

In this study, wheat flour used in Turkish noodle (eri?te) production was replaced with lupin flour (10, 20 and 30%) and lupin bran (10, 15 and 20%). Transglutaminase (TG) enzyme was used to improve technological properties of noodle. Some physical, chemical and sensory properties of the noodles were determined. As the lupin flour (LF) or lupin bran (LB) increased in the noodle formulation, water uptake values decreased, and cooking loss increased significantly (P<0.05). TG addition decreased the cooking loss values of noodles containing LF/LB. LF improved the nutritional status of noodle in terms of ash, protein and fat content, while significant (P<0.05) increase was observed in ash content of noodles prepared using LB. Calcium, copper, iron, magnesium, manganese and zinc content of noodle samples increased between 0.9 and 134 times with LF/LB substitution. Raw and cooked noodle samples with LF incorporated had the highest sensory scores particularly at 10% level.

Effects of Ultrasonication and Aqueous Ozonation on Gelatinization and Flow Properties of Potato Starch

ABSTRACT Ultrasonication and aqueous ozonation were applied to potato starch simultaneously. Flow properties (i.e., flow behavior index, n; consistency index, K; and apparent viscosity, ηapp) of samples were determined using a rheometer. A differential scanning calorimeter (DSC) was used to measure the gelatinization properties of samples (onset, peak and conclusion gelatinization temperatures and enthalpy of gelatinization). Results showed that ozonation caused a significant increase (p < 0.05) in onset gelatinization temperature (from 54.9 to 59.1 °C) and a significant decrease (p < 0.05) in enthalpy of gelatinization (from 14.6 to 12.2 J/g). There were no significant differences (p < 0.05) between the consistency index (ranged from 4.57 to 4.87 Pas) and apparent viscosity (ranged from 0.10 to 0.13 Pas) of samples treated with ozonation and ultrasonication with no regards of treating sequence. This showed that the order of treatment (i.e., ozonation and ultrasonication) does not have any significant effect on the flow properties of potato starch studied under the conditions applied in this research.

Combined effect ozonation and ultrasonication on rheological and thermal properties of rice starch in aqueous phase

A combination of ozonation and ultrasonication was applied to rice starch in aqueous phase. A Bohlin rheometer was used to obtain flow behaviour and consistency indices. A differential scanning calorimeter was used to measure the gelatinisation properties (onset, peak and conclusion gelatinisation temperatures and enthalpy of gelatinisation). It was observed that all starch samples exhibited non-Newtonian behaviour (i.e. n<1). The highest viscosity values (i.e. 0.5 Pa.s) and the highest shear-thinning effect (i.e. n=0.4) were observed for ultrasonicated starch sample. The consistency index for native rice starch increased after ultrasonication. There were no significant differences (P<0.05) between the consistency index and apparent viscosity of samples treated with ozonation and ultrasonication with no regards of treating sequence. This showed that the order of treatment (i.e. ozonation and ultrasonication) does not have any significant effect on the flow properties of rice starch studied under the condi...