Kumquat (Fortunella margarita) is a highly nutritious citrus fruit and used in traditional Chinese medicine due to its therapeutic effect against diseases. Due to its phenolic compounds, kumquat demonstrates high antioxidant activity and may, therefore, be evaluated as an ingredient to obtain functional foods. In this study, kumquat fruit which was dried by different techniques (convection, microwave and vacuum) was partially (10%, 20% and 30%) replaced with wheat flour in the formulation of biscuits. In this context, drying characteristics of kumquat powders dried by different techniques as well as some physical (color, texture, diameter, thickness, spreading ratio), chemical (moisture, ash, crude fat, crude protein, carbohydrate, energy, total phenolic and phytic acid content) and sensory properties of the biscuits were investigated. The L* values decreased, and a* and b* values increased with the usage of kumquat powder in the biscuit formulation. When the kumquat fruit powder substitution rate increased from 0% to 30%; the total phenolic content of biscuit samples increased from 746.18 μg GAE/mg to 2080.10 μg GAE/mg, while the content of phytic acid decreased from 116.86 mg/100 g to 53.60 mg/100 g. 10% kumquat powder substitution provided the most suitable rate for sensory acceptability of biscuits. The usage of kumquat powders in the production of biscuits may improve both sensory properties and functionality of end products. Also, microwave and vacuum drying may be used as suitable techniques to obtain kumquat powder.
kumquat, Fortunella margarita, microwave drying, vacuum drying, biscuit