Moist Heat Treatment Effect on Properties of Isolated Native Red Sorghum (Sorghum Bicolor) Starch
This chapter presents the results of moist heat treatments over native starch characteristics of red sorghum (Sorghum bicolor). The native starch was isolated from raw and moist heat treated (boiling, steaming and pressure cooking) red sorghum. The starch
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Moist Heat Treatment Effect on Properties of Isolated Native Red Sorghum (Sorghum Bicolor) Starch K. Santhi and T. Poongodi Vijayakumar
Abstract This chapter presents the results of moist heat treatments over native starch characteristics of red sorghum (Sorghum bicolor). The native starch was isolated from raw and moist heat treated (boiling, steaming and pressure cooking) red sorghum. The starch yield, physical properties (bulk density, true density and porosity), functional properties (water absorption capacity, oil absorption capacity and swelling power), pasting properties, α-amylase activity, morphological characteristics and qualitative modification in chemical composition (FT-IR and FT-NIR analysis) on moist heat treatments were determined. The moist heat treatments have not influenced the yield of starch (p < 0.05) but significantly reduced the pasting profile. The porosity of steamed starch was significantly (p < 0.01) lower than other starches. The pressure cooked starch exhibited very low viscosity and high α-amylase activity. The endosperm of the red sorghum (Sorghum bicolor) contained large (A granules) and small (B granules) starch granules. The surface of the starch granule appeared to be less smoother than potato starch granule. According to FT-IR spectrum, all the starch samples contained glucose, fructose, maltose, galactose, raffinose, aldehydes, aliphatic disulpides and metal azides and weak intensities of polyphenolic compounds and hexane. Relatively strong intensity of aldose sugar (glucose) in steamed starch and ketose sugar in boiled starch was observed.
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Introduction
Sorghum [Sorghum bicolor (L.) Moench], a tropical plant belonging to the family of Poaceae, is one of the most important crops in Africa, Asia and Latin America (Anglani 1998). The United States is the World’s largest producer of sorghum (Sorghum bicolor) grain followed by India, Nigeria, Africa and Mexico. It is an
K. Santhi • T. Poongodi Vijayakumar (*) Department of Food Science, Periyar University, Salem, Tamil Nadu 636011, India e-mail: [email protected] Mu. Ramkumar (ed.), On a Sustainable Future of the Earth’s Natural Resources, Springer Earth System Sciences, DOI 10.1007/978-3-642-32917-3_33, # Springer-Verlag Berlin Heidelberg 2013
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important food source in India and Africa. More than 35 % of sorghum grown is directly utilized for human consumption while the rest is used primarily for animal feed, and for the production of alcohol and industrial products (Awika and Rooney 2004; FAO 1995). Starch is the primary source of stored energy in cereal grains. Starch is used in a variety of food products as a raw material or as a food additive, and has an important role as thickener, bulking agent, gelling agent and water absorbent. It is used also in foods with varying moisture contents such as puddings, cookies, or drinks. Some of the starch derivatives are being increasingly used as fat substitutes (Cousidine and Considine 1982; Thompson and Issac 1967). Sorghum (S
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