Optimizing the effects of Persian gum and carrot pomace powder for development of low-fat donut with high fibre content

- Persian gum (PG) and carrot pomace powder (CPP) were used in donut formulation.
- PG and CPP considerably decreased fat content of donut.
- Higher PG and lower CPP levels improved physical properties of donut.
- CPP was found to increase the dietary fibre content of the donut.

The objective of present study was to develop and optimize a low-fat high fibre donut formulation using response surface methodology. A 5-level-3-factor central composite rotatable design was employed, where the independent variables were Persian gum (0-1.5 g/100 g), carrot pomace powder (0-15 g/100 g) and water (38-53 g/100 g), while the dependent variables were physicochemical properties of donuts. It was found that Persian gum and carrot pomace powder both effectively contributed to retention of donuts moisture content which in turn led to significant reduction of fat uptake during frying process (p<0.05). Persian gum decreased the donuts firmness while carrot pomace powder adversely affected the textural properties as well as specific volume (p<0.05). Image analysis revealed that carrot pomace powder influenced all the image analysis parameters investigated negatively. Response surface methodology described that donuts with optimum formulation of 1.20 g/100 g Persian gum, 6.45 g/100 g carrot pomace powder and 48.16 g/100 g water had considerably lower fat uptake and acceptable sensory attributes compared to control sample.