Original article Relationship between physicochemical and rheological properties of starches from Indian wheat lines Khetan Shevkani, 1 Narpinder Singh, 1 * Sandeep Singh, 1 Arvind Kumar Ahlawat 2 & Anju Mahendru Singh 2 1 Department of Food Science and Technology, Guru Nanak Dev University, Amritsar 143005, Punjab, India 2 Division of Genetics, Indian Agricultural Research Institute, New Delhi 110012, India (Received 3 April 2011; Accepted in revised form 3 August 2011) Summary Starches from nine Indian wheat lines were evaluated to study the relationships between physicochemical and rheological properties. Large granules (>15 lm) were present in the highest proportion followed by medium (5–15 lm) and small granules (<5 lm). Amylose content ranged between 27.4 and 37.2%. Starch with the highest proportion of large granules (68.9%) showed higher values of G¢ peak (576 Pa) and G¢ final (432 Pa). Amylose content showed positive relationships with retrogradation, gel firmness, gumminess and adhesiveness while negative with springiness. Cooked starch pastes with the highest amylose content (37.2%) had higher DH ret (0.88 J g )1 ), G¢ ret (361 Pa), adhesiveness (1.48 Ns), firmness (0.45 N) gumminess (0.22 N) and the lowest springiness (0.88). Amylose–lipid complex (AML) dissociation showed negative relations with swelling power, G¢ peak , G¢ breakdown and breakdown viscosity (r = )0.779, )0.66, )0.771 & )0.775, respectively, P < 0.05) while positive relationship with pasting temperature (r = 0.775, P < 0.05). Keywords Amylose, rheology, starch, textural, thermal, wheat. Introduction Starch is the most abundant constituent of wheat contributing significantly to the quality of the end use product. It is one of the primary sources of calories in the human diet and may be utilised in many of the industrial applications. The behaviour of starch as thickening and stabilising agents has provoked interest in its use in different formulations where it provides increase in the viscosity of the mixtures, improvement in the texture, and increase in the stability during storage, etc. Starch when heated to a high temperature in the presence of water, undergoes gelatinisation, character- ised by irreversible changes like granular swelling, crystallite melting, loss of birefringence, starch solubili- sation and viscosity development (Biliaderis, 2009). Gelatinisation and the subsequent retrogradation affect the rheological properties of cooked starch pastes. During processing, starches are subjected to a combi- nation of high heating and shear rate that also affect their rheological behaviour. Empirical methods, like viscographic analysis, have the limitations of inadequate data interpretation on structural basis compared to fundamental methods, like dynamic rheology, to study the heat-induced changes in aqueous starch dispersions. Although, the use of small- strain dynamic rheometry is not new in viscoelastic studies of starch, the development of oscillatory rheom- eters has prompted wider use of this technique to provide fundamental information on structural aspects of aqueous starch systems at molecular level (Autio, 1990). Determination of starch properties among diverse genotypes is essential to analyse the relationships between different properties. In this study, we corrob- orate our previous results for the starches isolated from various wheat lines (Singh et al., 2009) for understand- ing the role of physicochemical properties as well as to study their effect on the rheological characteristics of the starches separated from different Indian wheat lines. The present study will contribute to improved knowl- edge of relationships among the functional and rheo- logical properties of starches of different wheat lines developed in India. Materials and methods Materials Nine wheat lines i.e. P678-25-3, P695-5-1, P697-6, P697- 9, P701-4-1, HD2733, P684-4-1, P766-4 and BMQ4 were procured from Indian Agriculture Research Institute, *Correspondent: Fax: +91 183 2258820; e-mail: narpinders@yahoo.com International Journal of Food Science and Technology 2011, 46, 2584–2590 2584 doi:10.1111/j.1365-2621.2011.02787.x Ó 2011 The Authors. International Journal of Food Science and Technology Ó 2011 Institute of Food Science and Technology