Producing micro and nano fibers having high water holding capacity from tomato and wheat waste products and using them in model foods

Koçak, Gönül
The main objective of this study was to investigate the fibers and their effects and availability in ketchup (tomato fiber) and cake (wheat bran fiber) production. In order to this, rheological properties of ketchups with tomato fiber, and cake (100, 80, 60 g flour formulations) with wheat bran fiber in different concentrations were investigated. Tomato powder in ketchup and wheat bran in cake was used for comparison. The samples studied had pseudoplastic behavior having a definite yield stress with a good fit for the Herschel-Bulkley model. The viscosity and yield stress values increased as the percentage of fiber increased. Moreover the samples were found to be more elastic than viscous (G’>G’’). Both G’ and G’’ values increased with oscillatory frequency, percentage of fiber, and in cake samples decreased as the amount of flour decreased. Stability measurements of ketchups studied were done by using Lumisizer. The microstructure of tomato powder, wheat bran and fibers were investigated under SEM. It was seen that the fibers had branched, long and thin structure while the other two had lumy and thick structure. The pressure used, resulted in this structure with increased surface area and finally increased water holding capacity in fibers. Moreover, texture of cakes prepared was all investigated in terms of volume, outer surface, hardness, cohesiveness and gumminess. Finally it was found to be possible to produce healthier ketchups and cakes with fiber in a good quality by decreasing the other undesired ingredients.