Kevser Kahraman

Potential utilization of Mixolab for quality evaluation of bread wheat genotypes.

ABSTRACT The aim of this study was to determine the possibility of using Mixolab to assess the quality of different wheat genotypes. Mixolab data were compared with various flour quality characteristics and bread volume. The samples were chosen to represent a wide range in terms of grain and rheological properties and baking quality. There are eight paramaters used to evaluate a Mixolab curve. C1 and C2 are related to protein quality, whereas C3, C4 and C5 are related to the starch characteristics. Slopes α, β, γ are the indicators of protein weakening, starching speed, and enzymatic degradation. There were significant correlations between two Mixolab parameters (Stability and C2) and Zeleny sedimentation and Alveograph W values (P < 0.01). Some of the Mixolab parameters (C3, C4, C5) were correlated with Alveograph G and P/L value (P < 0.01). Mixolab values are generally in agreement with Farinograph values. There were significant negative correlations between most of the Mixolab parameters (Stability, C2...

Effect of Acid Modification and Heat Treatments on Resistant Starch Formation and Functional Properties of Corn Starch

In this study effects of acid hydrolysis, autoclaving and storage (95°C for 2, 3, and 4 days) on resistant starch (RS) formation in corn starch were investigated and functional properties of RS preparations were determined. RVA peak and final viscosity values of the RS preparations decreased gradually for each storage period with increasing hydrolyzation level. RS contents increased to 13.6–16.7% as a result of storage. RS contents of the samples dried without storage were lower than those of the stored samples up to 3.5 h hydrolysis. Solubility and water binding values of RS preparations were higher than those of the native and hydrolysed samples. In contrast to RS preparations, the native and hydrolysed samples affected the emulsion properties of soy protein inversely.

Optimisation of the reaction conditions for the production of cross-linked starch with high resistant starch content

The optimum reaction conditions (temperature and pH) for the preparation of cross-linked (CL) corn and wheat starches with maximum resistant starch (RS) content were investigated by using response surface methodology (RSM). According to the preliminary results, five levels were selected for reaction temperature (38-70 °C) and pH (10-12) in the main study. RS contents of the CL corn and wheat starch samples increased with increasing temperature and pH, and pH had a greater influence on RS content than had temperature. The maximum RS content (with a maximum p value of 0.4%) was obtained in wheat starch cross-linked at 38 °C and pH 12. In the case of CL corn starch, the optimum condition was 70 °C and pH 12. CL corn and wheat starch samples were also produced separately under the optimum conditions and their RS contents were 80.4% and 83.9%, respectively. These results were also in agreement with the values predicted by RSM.

Emulsion and Pasting Properties of Resistant Starch with Locust Bean Gum and their Utilization in Low Fat Cookie Formulations

In this study, emulsion and pasting properties of resistant starch (RS) preparations with/without locust bean gum and their utilization in low fat cookies were investigated. The acid-hydrolysed corn starch sample was autoclaved, stored at 95° C for 0, 2, 3, and 4 days for formation of RS preparations I, II, III, and IV, respectively. RS preparations had significantly lower peak and breakdown and higher trough viscosities than hydrolysed starch. RS preparations with gum resulted in a cold thickening capacity. While native and hydrolysed starches had deteriorative effect on emulsion capacity and stability of the soy protein, RS preparations (with/without gum) did not have a deteriorative effect. Reduction of shortening caused significant decrease in spread ratios of control cookies with/without gum. However, utilization of RS preparations in low fat cookies caused significant increases.

Optimization of resistant starch formation from high amylose corn starch by microwave irradiation treatments and characterization of starch preparations

The effects of microwave irradiation on resistant starch (RS) formation and functional properties in high-amylose corn starch, Hylon VII, by applying microwave-storing cycles and drying processes were investigated. The Response Surface Methodology (RSM) was used to optimize the reaction conditions, microwave time (2-4min) and power (20-100%), for RS formation. The starch:water (1:10) mixtures were cooked and autoclaved and then different microwave-storing cycles and drying (oven or freeze drying) processes were applied. The RS contents of the samples increased with increasing microwave-storing cycle. The highest RS (43.4%) was obtained by oven drying after 3 cycles of microwave treatment at 20% power for 2min. The F, p (<0.05) and R2 values indicated that the selected models were consistent. Linear equations were obtained for oven-dried samples applied by 1 and 3 cycles of microwave with regression coefficients of 0.65 and 0.62, respectively. Quadratic equation was obtained for freeze-dried samples applied by 3 cycles of microwave with a regression coefficient of 0.83. The solubility, water binding capacity (WBC) and RVA viscosity values of the microwave applied samples were higher than those of native Hylon VII. The WBC and viscosity values of the freeze-dried samples were higher than those of the oven-dried ones.

Resistant starch type V formation in brown lentil (Lens culinaris Medikus) starch with different lipids/fatty acids

This study aimed to characterize the brown lentil (Lens culinaris Medikus) starch and investigate the formation of amylose-lipid complexes (Resistant Starch Type V) by the addition of different lipids/fatty acids (10%, w/w) to both raw and cooked starch samples. Resistant starch content (measured by the official method of AACCI (Method 32-40), using the resistant starch assay kit) of raw brown lentil starch (BLS) increased significantly by the additions of lipids/fatty acids, starch sample complexed with HSO (hydrogenated sunflower oil) (14.1±0.4%) being the highest. For the cooked starch/lipid complexes, more profound effect was evident (22.2-67.7%). Peak, breakdown and trough viscosity values of the amylose-lipid complexed starches were significantly lower than that of BLS (p<0.05), while significant decreases in the setback and final viscosities were only detected in oil samples, but not in fatty acids. Each lipid in concern exerted different effects on the digestibility of starch and amylose-lipid complex formation while having no substantial differential effects on the thermal properties of starch depicted by differential scanning calorimetry (DSC). Amylose-lipid complex formation with suitable fatty acids/lipids seems a promising way of increasing resistant starch content of food formulations. Although the applications being quite uncommon yet, brown lentil seems to have potential both as a starch and also as a resistant starch source.

Formation of resistant starch from amylotype corn starch and determination of the functional properties

High amylose corn starch was hydrolysed with HCl at 40 °C for 0.5-2.0 h. Then the native and acid-modified starch samples were subjected to 2 different heat treatments (HT). In HT1, heat treated/autoclaved samples were dried after storage and in HT2, heat treated/autoclaved samples were dried without storage. Relative quantities of high- and medium-molecular weight fractions decreased and relative quantities of low-molecular weight fractions increased as a result of acid modification. Resistant starch (RS) contents of the acid-modified starches were between 15.7-16.4% and increased up to 29.4% due to HT1 and up to 17.5% due to HT2. The results indicated that RS contents of the high amylose starch can be increased by HT and storing prior to drying. Rapid ViscoAnalayser viscosity values decreased as the acid modification level increased. Water absorption and solubility values of the samples prepared with both heat treatments were higher than those of the native starch and hydrolysates. Emulsifying capacity/...