Characterisation of starches separated from sorghum cultivars grown in India Harinder Singh a , Navdeep Singh Sodhi a,b, * , Narpinder Singh a a Department of Food Science and Technology, Guru Nanak Dev University, Amritsar 143 005, Punjab, India b Food Physics Laboratory, Food Function Division, National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan article info Article history: Received 19 March 2009 Received in revised form 23 April 2009 Accepted 28 May 2009 Keywords: Sorghum starch Physico-chemical Morphological Thermal Retrogradation Pasting Texture abstract Starches from 15 Indian sorghum cultivars were separated and evaluated for physicochemical, morpho- logical, thermal, retrogradation, pasting and textural properties. The morphological characterisation revealed the presence of irregular-polyhedral as well as spherical shaped granules. A wide variation in amylose content ranging from 11.2% to 28.5% was observed. Thermal, retrogradation, pasting and textural characteristics also showed significant differences amongst all the starch cultivars. Principal component analysis was carried out to extract five principal components that could explain 75% of the total variance. The first two principal components PC1 (T o , T p , T c and DH gel ) and PC2 (amylose content, range of gelatin- isation, PHI and pasting and textural properties) could explain a cumulative variance of 44%, indicating the importance of amylose, thermal and textural properties on the sorghum starch functionality. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Sorghum (Sorghum bicolor (L.) Moench), a member of grass fam- ily, is the fifth leading cereal crop used throughout the world after wheat, rice, maize and barley (Suhendro, McDonough, Rooney, Wanishka, & Yetneberk, 1998). It is also referred to as ‘‘coarse grain” or ‘‘poor people crop” as it can sustain the lives of the poorest rural people (www.fao.org). It is grown in the arid and semi-arid regions of the world (Murty & Kumar, 1995) and is an important cereal due to its extensive drought resistance and requirement of relatively lower inputs (Watson, 1970) and hence called ‘Life Saver’ (www.fao.org). As more than 500 million people in the developing countries depend on sorghum as the main staple food (Mutisya, Sun, Rosenquist, Baguma, & Jansson, 2009) so rele- vant scientific information generated for this crop can certainly play a key role in agricultural development in these countries of the world (Palmer, 1992). Starch, nature’s most abundant polysaccharide, is a major food reserve providing energy often at a low cost in the human diet and having diverse applications both in food and non-food industries. These days the availability of corn to the Indian starch industry is decreasing day by day because of its increased demand by indus- tries involved in the production of breakfast cereals, snacks, etc. As sorghum, like other cereals, is rich in starch (approximately 70%) and has excellent potential for industrial applications (Zhan et al., 2003) it can be exploited for starch production. It is wet- milled similarly to corn for starch manufacture (Subramanian, Hoseney, & Bramel-Cox, 1994) and is technically equivalent to corn starch in its functionality (Freeman & Watson, 1971). As India pro- duces 7.24  10 6 metric tons of sorghum per annum and stands as the third largest producer in the world (www.fao.org) so there is enough potential in this crop to be utilised as a starch source. Keeping this in view, the present work was undertaken and starch was isolated from various sorghum cultivars and evaluated to ac- cess its possibility as a potential raw material for the Indian food industry. 2. Materials and methods 2.1. Materials Sorghum cultivars (SPV-824, CSV-14, CSV-16, CSH-16, M-35, IM-9B, SPV-669, CSV-13, Swathi, CSH-18, B-27, CSV-15, SPV-839, CSV-216, SPV-462) were procured from National Research Centre for Sorghum (NRCS), Hyderabad. SPV-669 was procured from Pun- jab Rao Deshmukh University, Akola, Maharashtra. All the seeds on manual examination had white pericarp. The seeds were tested for condensed tannins as described by Xie and Seib (2002). Sorghum kernels (15 g) were stirred in highly alkaline (7.5 g potassium hydroxide) sodium hypochlorite (5%) solution (70 ml) at 60 °C for 0308-8146/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2009.05.086 * Corresponding author. Address: Department of Food Science and Technology, Guru Nanak Dev University, Amritsar 143 005, Punjab, India. Tel.: +91 183 2258802x3430; fax: +91 183 2258820. E-mail addresses: navdeep@affrc.go.jp, navdeep_fst@yahoo.co.in (N.S. Sodhi). Food Chemistry 119 (2010) 95–100 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem