Effect of chitosan addition on proximate composition, antioxidant activity, and sensory acceptance of biscuits containing red and purple roselle extract

Abstract

The purpose of this research was to produce biscuits containing red and purple roselle extract with the addition of chitosan to improve the biscuits’ proximate composition, total phenolic, antioxidant activity, and sensory acceptance. The research used a completely randomized design with seven factors containing red and purple roselle extract, and chitosan, respectively; C1 (0:0:1)%; C2 (10:0:0)%; C3(0:10:0) %; F1(4:6:1)%; F2 (6:4:1)%; F3(4:6:2)%; and F4(6:4:2)%. Proximate composition (moisture, protein, fat, carbohydrate, ash and fibre) was determined using standard methods. The total phenolic content of roselle extract biscuits was measured using the Folin-Ciocalteau method, whereas the determination of antioxidant activity was carried out by applying the 2,2- Diphenylpicrylhydrazyl (DPPH) method. The proximate analysis of the biscuits produced high moisture content ranging from 3.25 to 3.94% W/W, protein content from 6.68 to 7.43% W/W, and fat content (19.13-19.74% W/W). The ash content varied from 1.62 to 1.72% W/W, fibre content ranged from 3.32 to 5.06% W/W, and carbohydrate contents were 62.50-65.40% W/W. The concentration of 1% chitosan in the biscuit formulation was also more effective in increasing the phenolic content and antioxidant activity (IC50), respectively 3.36 mg/100 g and 71.81 ppm in the F1 biscuits samples (red roselle 4% and purple 6%). Similarly, in F1 with the addition of 1% chitosan to sample biscuits containing red (4%) and purple (6%) roselle extract, the panellists received good acceptance of the aroma, colour, texture, taste, and overall biscuits made. Biscuits containing 6% purple roselle and 1% chitosan in the formulation could be provided with a significant contribution to increasing total phenol, antioxidant activity, and sensory acceptance compared to the others. Therefore, roselle extract and chitosan can be used as additional biscuit supplements that can increase nutritional content and antioxidant activity.