Effects of different pekmez (fruit molasses) types used as a natural sugar source on the batter rheology and physical properties of cakes

Five different kinds of fruit pekmez (mulberry, apricot, elecampane, grape and watermelon) were used in cake formulations as a natural sugar source. The rheologic properties of the batters and the physical and sensory properties of the cakes were investigated. Batter viscosity was measured at 15, 18, 21 and 24C using the Brookfield-type rotational viscometer. The power law model appeared to be suitable for describing the flow behavior of the cake batters containing pekmez as indicated by high r² values. n and k values ranged from 0.2528 (elecampane) to 0.5930 (mulberry), 124.38 (elecampane) and 13.42 (grape) at 24°C, respectively. However, the consistency index (k) of all samples decreased as temperature increased. The cake batters containing pekmez exhibited a pseudoplastic behavior. The replacement of sugar with pekmez in the cake formulations decreased the cake volumes. Elecampane bush (andız) pekmez gave the most reddish (a) batter color. The others decreased the L value and increased the a value of the batters. The cakes with watermelon were preferred by the panelists in terms of texture, odor, pore structure, wetness and overall acceptability. Fruit molasses (pekmez) is a very important food in human nutrition because of its high sugar, especially monosaccharides such as glucose and fructose, mineral and organic acid content. Therefore, pekmezes enhance nutritional properties and shelf life, and provide the desired flavor and color in cakes and other baked products. So, they can be used in the formulations of food products like cakes as a sweetener instead of sucrose. However, different food ingredients affect the rheology of food materials. Pekmezes affect the rheologic, physical and sensory properties of cakes and their batter. Rheologic, physical and sensorial properties are valuable information in product development. The rheologic properties of fluid foods are complex and depend on many factors such as the composition, shear rate, duration of shearing, and previous thermal and shear histories. The present study was conducted to determine the rheologic, physical and sensory properties of cakes formulated with different types of fruit pekmez in substitution for sucrose.