ISSN 2375-1231
African Journal of Crop Science ISSN 2375-1231 Vol. 6 (6), pp. 001-009, June, 2018. © International Scholars Journals
Full Length Research Paper
Amylopectin molecular structure and functional properties of starch from three Ugandan cassava varieties
Mufumbo Raphael1,2, Baguma Yona2*, Kashub Stephen2, Nuwamanya Ephraim2, Rubaihayo Patrick1, Mukasa Settumba1, Hamaker Bruce3 and Kyamanywa Samuel1
1Department of Crop Science, Makerere University Kampala, P. O. Box 7062, Kampala, Uganda.
2National Crops Resources Research Institute (NaCRRI), P. O. Box 7084, Kampala Uganda.
3Purdue University, Department of Food Science and Whistler Center for Carbohydrate Research,West Lafayette, IN 47907-2009, USA.
Accepted 04 April, 2018
Abstract
Amylopectin molecular structure is a very important determinant of starch functional properties. The main purpose of this study was to determine the strength of the relationship between the amylopectin structure of starches from cassava varieties and their functional properties. TME14 had the highest (46.63%) proportion of A chains while Bamunanika had the lowest 42.27%. Bamunanika had the highest (23.33%) proportion of B3+ chains while TME14 had the lowest 19.66%. TME14 had the highest amylopectin molecular weight 2.74x108 g/mol while NASE10 had the lowest 2.42x108 g/mol. TME14 had a higher gelatinisation temperature 65.37°C compared to the other varieties. Bamunanika had the highest final viscosity 2477.66 mPa s while NASE10 had the highest set back viscosity (494.50 mPa s). TME14 had the highest pasting temperature 67.80°C while NASE10 had the lowest 65.23°C. There was a significant negative correlation between final viscosity and A chains (r = -0.64), pasting temperature and A chains (r = - 0.77), A, B1 chains and gelatinisation temperature of retrograded starches (r = - 0.82, r = - 0.87), respectively, gyration radius and onset temperature of gelatinisation for the retrograded starch (r -0.56) and a significant positive correlation between B2 chains and pasting temperature (r = 0.94), amylopectin molecular weight and percentage retrogradation (r = 0.66). These findings revealed possible improvement through breeding for starch with desired qualities.
Key words: Amylopectin structure, cassava varieties, functional properties.