The effect of quinoa flour on wheat bread properties using fractal dimention based texture analysis of digital images

Wheat bread is the main source of food world eide. Currently, cereal grains and their products are known as a very good source of dietary fibers. One of the suitable solutions to improve the characteristics of bread is to use different sources of alternative fiber, such as pseudo-cereals loke quinoa. Quinoa with the scientific name (Chenopodium quinoa Willd) is a dicotyledonous plant and belongs to the Chenopodaceae family. This pseudo-cereal contains 16 essential and non-essential amino acids. For this reason, it is considered by the World Food and Agriculture Organization (FAO) as a functional food. . In this research, the effect of quinoa flour in levels of 25%, 50%, 75% and 100% with wheat flour in formulation of bread in presense and absence of improvers is investigated. color parameters, image texture (including: energy, entropy, contrast and homogeneity) , tortuosity, the microstructure of the bread core (including: the total number of holes, the size of the holes and the total surface of the holes) and the porosity of the bread core tissue were investigated. The results of this research showed that increase in the percentage of quinoa flour, lead to increase in the parameter L* (brightness level) and a* of the samples, while b* decreased. Results also show that By increasing the percentage of quinoa flour, the energy, entropy and homogeneity of the samples increased, while the amount of contrast and tortuosity of the samples decreased. The total number of and the size of the holes, the total area of the holes and the porosity of the samples increased. These parameters increased with the increase of quinoa flour up to 50%, while in the 75% and 100% Quinoa flour in formuation caused decrease in the parameters parameter. The porous in 75% and 100% quinoa flour samples were more circular and also had a smaller size than the holes in the other samples. According to the results of this research, it can be said that due to the irregular and complex morphological structure of bread, it is possible to use Fractal dimension to investigate the effects of processes and compounds, and also image texture analysis is well able to express texture changes. The core and prousity are the results of different formulations and considering the textural parameters including contrast, homogeneity, entropy and energy, these changes can be observed noticeably. Based on the results, it was found that the sample containing 50% quinoa flour with improver showed better textural characteristics