ORIGINAL ARTICLE Physicochemical properties of wheat-canna and wheat-konjac composite flours Aprianita Aprianita & Todor Vasiljevic & Anna Bannikova & Stefan Kasapis Revised: 25 February 2012 / Accepted: 4 April 2012 / Published online: 26 April 2012 # Association of Food Scientists & Technologists (India) 2012 Abstract Physicochemical properties of composite flours made of wheat from low to high protein contents and canna or konjac at different levels of substitution (0, 25, 50, 75, and 100 %) were prepared and analyzed. Compared to that of wheat flour alone, increasing levels of canna inclusions significantly increased the amount of resistant starch (RS) but decreased the protein content of composite flours. This substitution did not alter the total starch (TS), amylase and amylopectin contents of these mixtures. Changes in physi- cochemical properties were also observed in wheat-konjac composite flours. Increasing amounts of konjac flour de- creased the TS, amylase, amylopectin, and protein content of the mixtures, but increased the amount of RS. Substitu- tion of wheat flour with 75 % of canna or konjac flours in HPWC (High Protein Wheat-Canna), HPWK (High Protein Wheat-Konjac), and LPWK (Low Protein Wheat-Konjac) increased the swelling power of these mixtures at 80 and 90 °C. In general, substitution of wheat flour with up to 50 % of canna or konjac flours did not cause any other observable decline. In addition, the substitution of wheat flour with canna or konjac flours increased the gelatinization temperature of all composite flours. Keywords Composite flour . Physicochemical properties . HPWC . HPWK . LPWC . LPWK Introduction Indonesia has many tropical root and tuber crops that can be used as alternative sources of carbohydrate. These crops in- clude taro (Colocasia esculenta), yam (Dioscorea alata), sweet potato (Ipomoea batatas), canna (Canna edulis), konjac (Amorphophallus campanulatus), arrowroot (Marantha arun- dinaceae), and cassava (Manihot uttilisima) (Deshaliman 2003). Flours and starches isolated from roots and tubers of these plants usually have higher viscosity compared to that of cereal flours, which allows them to be used as thickening or gelling agents in some food products. In addition, these iso- lated materials have higher paste clarity, which is important for certain food applications. Compared to cereal flours and starches, these materials also have less starchy flavors (Radley 1976; Moorthy 2002). Moreover, these materials also offer health benefits especially in preventing obesity, constipation, cardiovascular disease, diabetes and colon cancer due to the high amount of fiber content (Chen et al. 2003). The absence of gluten within these materials may help provide nutrition for those who have celiac disease (CD) (Hung and Morita 2005). Except for cassava and sweet potato, many of these starchy materials have not been utilized optimally due to the lack of knowledge of suitable processing techniques and product development (Deshaliman 2003; Nasution 2003). Canna and konjac are among these underutilized roots and tubers even though they have been consumed as a source of carbohydrate by local people in rural areas. Flour and starch A. Aprianita : T. Vasiljevic School of Biomedical and Health Science, Victoria University, Werribee Campus, Melbourne, Victoria, Australia T. Vasiljevic Institute for Sustainability and Innovation, Faculty of Health, Engineering and Science, Victoria University, Werribee Campus, Melbourne, Victoria, Australia A. Bannikova (*) : S. Kasapis School of Applied Sciences, RMIT University, City Campus, Melbourne, Victoria 3001, Australia e-mail: anna.bannikova@rmit.edu.au J Food Sci Technol (September 2014) 51(9):1784–1794 DOI 10.1007/s13197-012-0696-x