Improving the quality properties and antioxidant activities of cake using kumquat (Fortunella margarita) fruit powder

The main objective of the present study was to evaluate the effect of the substitution of 5 and 10% of soft wheat flour with kumquat powder (KP) in cake production as a source of natural antioxidants to obtain cake with improved sensory and nutritional properties, minimize lipid oxidation and extend the shelf-life of cake. The cakes were tested for chemical composition, pasting profile, baking quality, color, sensory properties, and texture. On the other hand, total phenols, flavonoids and antioxidant activity (DPPH%) of the kumquat cake were determined. Also, fats were extracted from cakes made from KP and antioxidant activities during storage for two weeks in room temperature 20:25˚c were evaluated by the determination of acid value, peroxide value and thiobarbituric acid. The partial replacement of wheat flour with KP caused a significant differences (p<0.5) in weight, volume and specific volume, whereas it caused a significant decrease in luminosity, and a significant increase in red and yellow intensity in the crust and crump. 5% KP cake recorded the best overall acceptability scores and the highest protein content; whereas the highest moisture, ash and fiber found in cake with 10% KP. DPPH scavenging activities, Total phenolic and total flavonoids contents increased by increasing the KP percent in cake. KP had an effect on the stability of the cakes as ketonic reactions was consistently repelled due to its high amounts of phenolic compounds which enable it to play an important role in improving the antioxidant activity in cake during storage.