Browsing by Author "Boyacioglu, M. H."

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Citation Count: 1
Effect of wheat protein isolate addition on the quality of grape powder added wheat flour extrudates
(Wageningen Academic Publishers, 2016) Tacer-Caba, Z.; Nilufer-Erdil, D.; Boyacioglu, M. H.; Ng, P. K. W.
Addition of bioactive ingredients into cereal products is reported to have some detrimental effects on the product quality. However, sometimes those negative effects are known to be compensated by protein sources. In this study, the single and combined effects of both Concord grape extract powder (CGEP) and wheat protein isolate (WPI) on quality parameters of hard wheat flour extrudates were investigated. Beside the physical quality and colour parameters of extrudates, their pasting and thermal properties were also evaluated at three different die temperatures. Results revealed that CGEP substitution (7%), even with WPI (6.5 and 13%), was not so much effective on quality of extrudates extruded at 90 and 120 degrees C die temperatures. The only parameter effective on quality was the die temperature; especially at 150 degrees C, differences between formulations were more distinct for (diametric expansion, bulk density) when compared to lower die temperatures (90 and 120 degrees C). However, pasting properties were detrimentally affected by the single addition of CGEP (about 55.4% loss in final viscosity) with respect to single WPI substitution (about 66.7% loss in final viscosity). Presence of both CGEP and WPI made the pastes even weaker (34.1 to 61.1% decrease in peak viscosity), on the other hand, decreased the extent of delay (in gelatinisation (about 2 to 9 degrees C) provided by the sole use of CGEP. Besides no distinct effect on retrogradation was observed neither by CGEP nor with WPI. Therefore, in extrudates, CGEP substitution and related decrease in protein content did not exert a significant quality loss and even by increasing the protein level no improvement in quality parameters was obtained.
Citation Count: 2
EFFECTS OF TEMPERATURE, SHEAR RATE AND PROCESSING ON THE RHEOLOGICAL PROPERTIES OF SALEP DRINK
(Chiriotti Editori, 2014) Kagan, D. Arduzlar; Boyacioglu, M. H.; Boyacioglu, D.
The effects of shear rate, temperature and processing on the rheological properties of commercial salep drinks (UHT processed in liquid form, powdered forms both instant and traditionally cooked type) are investigated. The empirical power law model is used for the determination of the flow behavior and consistency index. Apparent viscosity of salep drink decreased with increasing shear rate. The salep drink exhibited a pseudoplastic or shear thinning behavior. Processing affected the flow behavior and consistency indices significantly (p <= 0.05). The flow behavior index of samples was in the range of 0.51-0.74 while the consistency index changed in the range of 0.14-2.68 Pa.sn. The lowest flow behavior index and the highest consistency index value are determined with the instant salep drink, while the highest K value was recorded for it. The flow behavior index increased and the consistency index decreased with processing temperature. In sensory analysis, salep drinks were evaluated for flavor, consistency and overall acceptability. A single rheological model is developed to express combined effects of shear rate (by Power law model) and temperature (by Arrhenius equation) on the apparent viscosity of an instant salep drink preferred by the sensory panelists in all samples. This study is expected to standardize the product formulation and facilitate equipment and process design.