Physical, microbiological and sensory quality of gluten-free biscuits prepared from rice flour and potato pulp

In order to use the starchy residue recovered from the effluent of fries-processing industry, to reduce losses of the industry and to add value to the products, this study aimed to evaluate the physical and microbiological viability, and sensory acceptability of biscuits formulated with different levels of rice flour (RF), and acidified dehydrated recovered potato pulp (PP). Completely randomized design with five treatments (no PP, and substitution of 200, 400, 600 and 800 g.kg(-1) of RF by PP) and four replications were used to evaluate physical and sensory characteristics of samples. Biscuits showed water activity of 0.11-0.32, specific volume of 1.38-1.96 l.kg(-1), brightness between 76.22 and 81.37, hardness from 16.70 N to 42.98 N, and showed no contamination by coliforms at 45 degrees C, coagulase positive Staphylococcus sp. and Salmonella sp. Except for the biscuit without PP, all formulations were above the average score limit set for sensory acceptance (six), but the biscuit which obtained the best score of sensory and physical properties was the one with 600 g.kg(-1) PP replacing RF. It is concluded that is it is viable to produce gluten-free biscuits with a substitution of up to 80% of RF by PP recovered from effluent of fries-processing industry, considering physical, microbiological and sensory parameters.