Development of low fat soft dough biscuits using carbohydrate and protein based fat replacers
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Date
2012-05
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
An investigation was carried out to develop low fat soft dough biscuits using carbohydrate and protein based fat replacers. Three different products containing combination of maltodextrin and guar gum; polydextrose and guar gum; and Simplesse were optimized using response surface methodology. A central composite rotatable design was used to optimise the level of sugar, composite fat, ammonium bicarbonate and water for production of low fat biscuits. Optimization was done on the basis of spread ratio, hardness, stress-strain ratio and overall acceptability. The optimized low fat soft dough biscuits packaged in LDPE bags and stored at 15-25°C were analyzed for physical, chemical and sensory attributes for 90 days. The rancimat study and moisture isotherm behaviour of biscuits were also determined.
Investigations indicated that increasing the level of sugar and ammonium bicarbonate increased the diameter, spread ratio and spread factor of biscuits. Hardness of biscuits increased whereas texture, taste, flavour and overall acceptability scores decreased with increase in level of fat replacers. On the basis of studies conducted using RSM, the optimum formulation for low fat biscuits containing maltodextrin and guar gum had sugar 31.74 g, fat 13.55 g, maltodextrin 21.15 g, guar gum 0.3 g, ammonium bicarbonate 2.21 g and water 21 ml (per 100 g flour basis). Low fat biscuit containing polydextrose and guar gum had optimum levels of sugar 24 g, fat 10.5 g, polydextrose 24.2 g, guar gum 0.3 g, ammonium bicarbonate 2 g and water 24 ml, (per 100 g flour basis) whereas the optimized product containing Simplesse required sugar 29.88 g, fat 19.25 g, Simplesse 15.75 g, ammonium bicarbonate 2.26 g and water 21.5 ml (per 100 g flour basis).
Moisture content (per cent) of all the low-fat biscuits was higher than control. Biscuits made using Simplesse had significantly higher protein content (10.07 per cent) than the control. The optimized products had significantly lower amount of fat (p<0.05) than control. The amount of fat in control, low fat biscuit containing maltodextrin and guar gum, polydextrose and guar gum, and Simplesse was 21.47, 7.99, 6.45 and 11.98 per cent, respectively.
During storage for 3 months at 15-25°C, the moisture content, free fatty acid content and peroxide value of control as well as optimized low fat products increased significantly. Also, a significant decrease in hardness and scores of taste, flavour and overall acceptability was observed; however the decrease was higher in control biscuits than in low fat biscuits. Maximum induction time was observed for low fat biscuits containing polydextrose and guar gum while minimum for control biscuits using rancimat.
Equilibrium moisture content of biscuits increased with increase in water activity. Smith model was recommended for describing the sorption behaviour for all types of biscuits.
The results of the investigation concluded that low fat highly acceptable soft dough biscuits can be prepared by replacing 62.8, 70 and 44 per cent of fat using maltodextrin and guar gum, polydextrose and guar gum and Simplesse, respectively and they can be stored well for 3 months at ambient conditions. The product containing polydextrose and guar gum exhibited best organoleptic characteristics and maximum shelf life.
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Thesis-PhD
Keywords
carbohydrates, proteins, nutritive value,bakery, food products, biscuits, low fat products, storage life, storage quality