This study was carried out to evaluate the effect of substitution of soft wheat flour (SWF) with 3, 6, 9 and 12 % tomato peel powder (TPP) and 5, 10, 15 and 20% orange peel powder (OPP) on rheological, chemical, baking quality, color, sensory characteristics, texture, stalling and shelf- life of cake.
Results showed that, rapid visco-analyzer (RVA) parameters showed that substitution of OPP and TPP to SWF (72% extraction) at different levels decreased the peak viscosity, trough, breakdown, final, and setback viscosities. While peak time and pasting temperature values ranged between 10.7 to 11.7min and 55.3 to 94.7ºC respectively for both OPP and TPP supplementation percent. Also, the partial replacement of SWF with OPP and TPP increased chemical composition % (moisture, crude protein, lipids, ash, and crude fiber) of cake samples, while total carbohydrates were decreased in parallel with increasing the level of substitution compared with control cake samples. Baking quality cake treatments containing OPP and TPP have also results showed that with increasing levels of OPP and TPP in cake, weight was gradually increased, while volume, specific volume and weight loss were decreased significantly when compared tocontrol cake. The control cake had the highest L values (37.93 and 61.25) for crust and crumb with significant (p ≤ 0:05) increases compared to other cake samples, while a* and b* values decreased compared to cake samples containing OPP and TPP at different levels. The results of sensory evaluation show that OPP and TPP enhanced all sensory characteristics (taste, texture, odor, color, appearance and overall-acceptability) of cake comparing with the control. The enhancement increased with increasing the level of OPP and up to 15% and TPP up to 9%.
The results of texture profile show that, all additions were increase hardness by increasing addition levels comparing with control sample, while cohesiveness, springiness, gumminess, chewiness, adhesiveness and resilience. The results showed a decrease in the percentage of freshness in the cake samples containing OPP and TPP at 5, 10, 15, and 20%; 3, 6, 9 and 12%, respectively.
Conclusively, from the results it could be concluded that, it is feasible to produce functional cake samples from mixture of SWF, OPP and TPP with good nutritional value and high sensory characteristics nearest to cake samples from control (100 %SWF). Finally, Wheat flour could be replaced by 3.0 to 6.0% of TPP and 5.0 to 10.0 % OPP with good properties and high nutritional value of cakes.