Investigation of hydrocolloids affecting the structure using rheologic and microscopic methods in bread technology

In this research; three types of gums (guar gum, locust bean gum, xhantan gum) among the hydrocolloids have been studied in terms of their rheological properties in bread making quality. Under light microscopy; there were significant differences in crumb pore (air) sizes. It is interesting to see that, bread containing 2.5% GG sample gave a homogenous small pore size compared to 5% KG sample which produced almost no visible pore size. When the volume of the bread was evaluated; KG samples produced the least bread volume and the volume of the bread decreased as the concentration of KG increased. Highest bread volume was obtained from 5% GG sample and generally galactomannan samples (GG, LBG) contributed to higher bread volumes. SEM analysis confirmed that three different gum additions at three different concentrations resulted in significant differences in texture of the bread. When TPA results were evaluated; the biggest differences were observed in hardness parameters. This was followed by gumminess and chewiness parameters; however there weren?t huge differences in springiness, cohesiveness and resilience parameters. In addition it was observed that the hardness parameters were increased when the concentration of galactomannans increased which is in complete contrast to KG. Crumb colour analysis showed that the results were significantly different (p< 0.05). Parameter ?L? ranged between 57.97 and 77.48, parameter ?a? between 1.77 and 2.17, and parameter ?b? 6.80 and 15.13. In general; at the end of texture (TPA, SEM), colour and sensory analysis, use of gums as food additives could be useful in bread making technology providing textural support, crust volume control and improving its water binding capacity. In addition, research concentrating on the use of gums as a source of natural dietary fibre in today?s modern diet would be useful. Key Words: Hydrocolloids, rheology, bread quality, SEM, TPA