E-mail: ooawolu@futa.edu.ng, Registrant ID# 2156 Sp24-12 Effect of some chemical modification methods on physico-chemical, functional and pasting properties of native and modified water yam (Dioscorea alata) starches. Olugbenga Olufemi Awolu1*. Department of Food Science and Technology, Federal University of Technology, Akure, Nigeria. E-mail: ooawolu@futa.edu.ng, Registrant ID# 2156 Introduction Starch, as a major reserve substance of plant sources, contributes to the appearance, structure and quality of food products (Lawal and Adebowale, 2005). Native starches are undesirable for many industrial applications because of their inability to withstand processing conditions such as extreme temperature, diverse pH and high shear rate (Singh et al., 2007). Modification of native starches improves its desirable functional properties. In this study, Water yam starch was isolated and subjected to chemical modification by acetylation, oxidation and acid thinning. Chemical composition, functional properties and pasting characteristics of native and modified starches were analyzed using standard methods and compared with commercially available cassava starch. M&M Water yam was locally obtained. Cassava starch was obtained from Matna Industries, Owo, Nigeria. Starch extraction (Riley et al. 2006), Acetylation and acid thinning (Sathe and Salunkhe, 1981), Oxidation (Lawal, 2004); Proximate properties (AOAC, 2005), Functional properties and pasting characteristics of native and modified water yam starches were evaluated Results Table 1: Result of Proximate composition of Native and Acetylated Water Yam Starches Table 2: Functional Properties, Resistant Starch and Sugar Content of Native and Acetylated Samples Table 3: NaYS AcYS * NaYS = Native water yam starch, AcYS = Acetylated water yam starch, AtYS = Acid thinned water yam starch, OxYS = Oxidized water yam starch, CaVS = Commercial starch Conclusion OxYS AtYS chemical modification improved AtYS the attributes hence good sources of edible and industrial starches. CaVS (use the bottom of the poster only is necessary) Starch Yield (%) Moisture (%) Ash (%) Fat (%) Crude fibre (%) Protein (%) Amylose (%) NaYS 21.67d±1.80 8.09d 0.35b 3.37a±0.02 ND 0.44b 12.53b±0.08 AcYS 97.30a±0.82 11.65a±0.04 0.20d 2.27c±0.02 0.33c±0.02 9.42e±0.03 AtYS 85.30c±0.61 9.69c±0.02 0.55a 2.11d±0.01 0.43b 10.57c±0.02 OxYS 90.33b±1.30 9.96b±0.01 0.35c 2.87b±0.02 0.41b 9.95d±0.01 CaVS   6.43e 0.15e 0.92e±0.03 1.29a±08 21.50a±0.05 Starch WAC (g/g) OAC (g/g) Bulk density (g/cm3) Resistant starch (%) Total sugar (%) NaYS 1.17a±0.01 0.40b±0.58 0.85a±0.02 18.25d±0.25 0.064b±0.002 AcYS 1.09b±0.01 0.46b±0.01 0.81b±0.03 21.47c±0.03 0.053d±0.001 AtYS 0.99c±0.01 0.88ab±0.01 0.79b±0.02 18.35d±0.05 0.063b±0.001 OxYS 0.68e±0.01 0.59b±0.01 21.95b±0.05 0.056c±0.003 CaVS 0.90d±0.03 1.18a±0.01 0.73c±0.01 23.70a±0.20 0.085a±0.002 Starch P.V (BU) Tr (BU) FV (BU) SV (BU) BV (BU) PT (min.) P (oC) NaYS 32.85 3.69 78.67 45.82 29.17 6.85 93.65 AcYS 34.42 3.92 83.56 49.14 30.50 6.55 94.45 AtYS 66.08 62.08 235.42 169.33 4.00 6.93 94.52 OxYS 76.58 32.00 64.42 -12.16 44.58 6.49 92.58 CaVS 802.83 609.75 257.25 -545.58 192.25 6.92 92.42