Effect of Drying Temperature on Physiochemical Properties of Powder from Blanched and Unblanched Lemon Peel and Sensory Quality Evaluation of the Powder Fortified Biscuits

Abstract

Preparation of biscuit incorporating lemon peel powder can be a new approach in formulating fortified fast food. This investigation was made to evaluate quality of prepared biscuits with lemon peel powder. The effect of temperature on drying time and physiochemical properties of lemon peel powder and their effects on biscuits were also examined. Two drying temperatures (65⁰C and 75⁰C) were employed for both blanched and unblanched lemon peel. The formulated biscuit samples incorporating 1 % lemon peel powder were compared with control biscuits which were prepared with 100% wheat flour. It took longer time (18 hr) for drying of blanched sample at 65 ⁰C whereas shorter time (8 hr) was required for that of blanched sample at 75⁰C. There was a significant decrease in the physiochemical properties of lemon peel powder with the increase of temperature except protein and fibre content. In addition, moisture content of the unblanched sample was found to be lower than the blanched sample at the same temperature. Significantly higher ascorbic acid was obtained by the unblanched samples. Protein and fibre content for both unblanched and blanched sample at the same temperature were found to be higher. All the samples were significantly different at 5% level of significance for overall acceptability. Biscuits prepared with unblanched dried lemon peel powder (at 65⁰C) sample secured the highest score in case of all the sensory parameters. Therefore, quality fortified biscuit can be prepared commercially by incorporating 1 % lemon peel powder in wheat flour for the fast food consumer.