Background. There is a discernible increase in consumer demand for products that contain reduced levels of fat. Such products are made using raw materials that have high biological potential as part of their production process. Materials such as protein fiber which can be obtained from by-products created during juice processing, are examples of such biological potential. The  utilization of a fiber preparation derived from carrot pomace in pastry production presents novel possibilities for managing waste in the food industry and aligns with the ethos of sustainable  development and a circular economy. Our study aimed to assess the possibility of decreasing fat content in sponge cake muffins by replacing it with a carrot fiber preparation. Rapeseed oil was  substituted in muffin recipes with carrot fiber at a level of 10 ÷ 30 % fiber. The carrot fiber content in the analyzed samples ranged from 0.75 to 2.25 %. Texture, color and sensory evaluations were conducted for analysis.
Results and conclusions. Reducing the fat content in sponge cake muffins to 25 % and substituting it with up to 1.88 % of carrot fiber preparation neither led to weight loss nor affected the  crumb bulk weight, diameter or texture parameters of the products. However, the preparation did cause significant changes in the products’ color. Considering the physical and sensory quality,  it was demonstrated that the utilization of a carrot fiber preparation in the production of sponge-fat products was feasible to some extent. The involvement of this preparation makes it possible  to effectively decrease the fat content by 20 %, while maintaining the quality features and appeal of sponge-fat products. However, when more fat is reduced and more fiber is added, this lead to  the product quality being impaired.