Physicochemical, rheological and cookie making properties of corn and potato flours

The physicochemical and rheological properties of corn flour and flours made from three potato cultivars (Kufri Jyoti, Kufri Badshah and Pukhraj) were studied. Potato flour showed higher amylose content, water absorption index and solubility than corn flour. The rheological properties (G′, G″, η′ and tan δ), measured using a dynamic rheometer, of corn and potato flours differed significantly. Potato flours showed higher G′, G″ and η′ than corn flour. The potato flours made from different cultivars also showed significant differences in various rheological parameters. Kufri Jyoti flour showed the highest G′, G″ and η′ among the potato flours. The effects of blending corn flour and potato flours at different levels (2, 4 & 6%) with wheat flour on cookie-making properties were also studied. The addition of both corn and potato flours improved the cookie spread factor and lowered cookie fracture force. However, the effect of potato flours on cookie spread and fracture force were higher than corn flour. Colour parameters (L∗, a∗, b∗) of cookies were measured using a Hunter colorimeter. L∗ value of cookies decreased while a∗ and b∗ values increased with increase in level of both corn flour and potato flours. The addition of potato flours brought greater changes in L∗, a∗ and b∗ values than corn flour at corresponding levels.