Date

2015

Author

Topaloğlu, Tuğçe

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Several health problems like diabetes and obesity are associated with consumption of highly fatty food, leading consumers to be more conscious about what they eat. This concern has been a driving factor for manufacturers to research and develop low- or reduced-fat products. Therefore, the baking industry finds new ways to respond to the demands. For this reason, fat replacement in bakery products has gained a popularity. Maltodextrin is commonly used to trim fat from bakery products because it gives some properties to products similar to those of fat. The main objective of this study was to investigate the effects of microfluidization (MF) and maltodextrin (MD) (DE18) (0%, 3.75%, and 7.5%) on the rheological and textural properties of cookie and cookie dough. Also, the effects of type of fat - palm olein (PON) and palm stearin (PS) - on the rheological and textural properties of both cookie and cookie dough were investigated. In the first part of the study, the rheological (elastic and viscous moduli) and hardness and cohesiveness of cookie doughs containing different percentages (0%,3.75%, and 7.5%) of MD were observed. The cookie doughs showed a solidlike behavior. The elastic and viscous moduli were low in the control dough, containing 100% PON or PS without no fat replacement, compared to those of dough with fat replacement. It was observed that the use of MD at 0%, 3.75%, and 7.5% increases both storage and loss moduli in all samples. Also, the G' and G" of doughs containing MD at 0%, 3.75%, and 7.5% were affected by the application of MF at 1000 Bar. The cookie dough containing 3.75% MD, PON2, had the closest G' and G" values to the control cookie dough. Dough hardness increased as the percentage of MD increased whereas increase in the amount of MD led to reduction in the moisture content of doughs both with MF and without MF. However, MF did not have a significant effect on the moisture contents of doughs. Control dough had the highest cohesiveness value. However, replacement of fat with MD at different percentages decreased cohesiveness of doughs. In the second part of this study, the effects of replacement of fat by MD at 0%, 3.75%, and 7.5% on quality of cookies (hardness, moisture content, size, and color) were determined. There was an increase in the hardness of cookies with the increasing percentages of MD. Consequently, it could be concluded that there was a correlated relation between cookie and its dough in terms of hardness because increase in hardness of both cookie and dough was observed with increasing MD level. Also, MD increased the moisture content of the cookies, compared to control cookie. There were no significant changes in the heights of all types of cookies after 7 day storage. In diameter measurement, there was no significant difference between the cookies without MF at 0%, 3.75%, and 7.5% MD. However, there was a significant difference in diameter between cookies with MF at different MD percentages. On the other hand, the increase of MD levels in the cookie and the use of MF process did not any significant effect on the change of the cookie color. The significant effect of MF on color was only observed with the cookie prepared from 0-day dough including PS. In the study, it was found that the use of MF at 0%, 3.75%, and 7.5% MD was not required for the cookie making because no significant effect on hardness and size of cookie was observed. On the contrary, using MD18 was a good option for fat replacement in cookie making in terms of textural and rheological properties. Also, when 3.75% MD was used, the cookie (PON2) with 20% less calorie was obtained if the control cookie was considered as a baseline.

Subject Keywords

Cookies., Dextrins., Rheology., Food texture, Microfluidization.

URI

http://etd.lib.metu.edu.tr/upload/12618879/index.pdf
https://hdl.handle.net/11511/24750

Collections

Graduate School of Natural and Applied Sciences, Thesis