Synthesis of resistant starch in three Rwandese cassava varieties and its applicability in yoghurt processing A proposal Presentation at the Department of Food Science, Nutrition and Technology, University of Nairobi 16th August 2016 University of Nairobi ISO 9001:2008 1 Certified http://www.uonbi.ac.ke
The University of Nairobi Student: Herve Mwizerwa A56/81986/2015 Supervisors: Dr. George O. Abong' (PhD) Dr. Martin Patrick Ongol University of Nairobi University of Rwanda Prof. M.W. Okoth Dr.-Ing. Calvin Onyango University of Nairobi Kenya Industrial Research and Development Institute University of Nairobi ISO 9001:2008 2 Certified http://www.uonbi.ac.ke
CHAPTER ONE: INTRODUCTION 1.1. Background information Starch is the most abundant storage polysaccharide in plants. Contributed mainly by cereal grains, root crops and tubers. Based on Digestibility, it can be classified as: Rapidly digestible starch, Slowly digestible starch, Resistant starch University of Nairobi ISO 9001:2008 3 Certified http://www.uonbi.ac.ke
Background information cont’ Resistant starch (RS) is the sum of starch and products of starch degradation not absorbed in the small intestine of healthy humans. Types: RSI: physically inaccessible to digestion RSII: undigestible due to its conformation (ungelatinized starch) RSIII: retrograded starch formed during cooling of gelatinized starch RS IV: chemically modified starch University of Nairobi ISO 9001:2008 4 Certified http://www.uonbi.ac.ke
Functions of Resistant starch Act as a substrate for microbial fermentation in large intestine, Production of short chain fatty acids Helpful in preventing colon diseases (ulcerative colitis and colorectal cancer), Positive effects on diabetes, cardiovascular diseases, colonic health and obesity. Improves lipid and cholesterol metabolism Prebiotic properties University of Nairobi ISO 9001:2008 5 Certified http://www.uonbi.ac.ke
1.2. Problem statement Variations in RS contents of popular cassava varieties in Rwanda and effects of applying different heat treatments on cassava starch is not yet established, There is a gap in cassava value addition in Rwanda where its industrialization is limited to manufacturing of flour - low diversification. Yoghurt processing in Rwanda rely on imported and relatively expensive corn starch. University of Nairobi ISO 9001:2008 6 Certified http://www.uonbi.ac.ke
1.3. Justification of the study Cassava ranks second in country after plantains in terms of production quantity with 3,161,470 MT in 2013 (FAOSTAT, 2013). Production of RS provides an opportunity to preserve the produce and its value addition. Yoghurt can be produced cost-effectively if all ingredients are sourced within the country. RS is a prebiotic which, when mixed with probiotic yoghurt culture will result into symbiotic and healthy product - contribute towards reduction of high colorectal cancer case in sub-saharan Africa. University of Nairobi ISO 9001:2008 7 Certified http://www.uonbi.ac.ke
Overall objective 1.4. Objectives To synthesize Resistant starch (RS) from three Rwandese cassava varieties and evaluate its applicability in yoghurt processing. University of Nairobi ISO 9001:2008 8 Certified http://www.uonbi.ac.ke
Specific objectives To determine the levels of RS in three Rwandese cassava varieties namely NASE14, THEI92/0057 and GARUKUNSUBIRE. To assess the effect of hydrothermal modification on the RS content in starch extracted from 3 Rwandese cassava varieties. To produce yoghurt with cassava starch high in RS and tests its quality and sensory acceptability. University of Nairobi ISO 9001:2008 9 Certified http://www.uonbi.ac.ke
1.5. Hypothesis There is no significant difference in RS among three popular Rwandese cassava varieties. Hydrothermal treatments do not significantly increase RS content in cassava starch. RS synthesized from cassava starch does not alter quality and sensory properties of yoghurt. University of Nairobi ISO 9001:2008 10 Certified http://www.uonbi.ac.ke