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SEM images indicated that surface of oxidized maize starches were rougher than native starch. The surface of oxidized starches became rougher with increasing hypochlorite level in comparison with native starch. However, the DSC results illustrated that there was no significant difference of gelatinization temperature between the native starch and oxidized starches. | Tạp chí Khoa học và Công nghệ 54 (3) (2016) 347-355 DOI: 10.15625/0866-708X/54/3/7101 OXIDIZED MAIZE STARCH: CHARACTERIZATION AND ITS EFFECT ON THE BIODEGRADABLE FILMS I. CHARACTERIZATION OF MAIZE STARCH OXIDIZED BY SODIUM HYPOCHLORITE Dao Phi Hung*, Truong Thi Nam, Mac Van Phuc, Nguyen Anh Hiep, Trinh Van Thanh, Nguyen Thien Vuong Institute for Tropical Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Viet Nam * Email: dphung@itt.vast.vn Receipted: 21st September 2015; Accepted: 19 February 2016 ABSTRACT The effects of hypochlorite level, i.e. 0.5; 1 and 2 active chlorine g/100g starch, on the structure and physicochemical properties of oxidized maize starch were investigated. The obtained results show that oxidation degree grew up with increasing hypochlorite concentration, especially, the carboxyl content saw higher increase than the content of carbonyl. SEM images indicated that surface of oxidized maize starches were rougher than native starch. The surface of oxidized starches became rougher with increasing hypochlorite level in comparison with native starch. However, the DSC results illustrated that there was no significant difference of gelatinization temperature between the native starch and oxidized starches. Keywords: sodium hypochlorite, maize starch, oxidation, starch oxidized. 1. INTRODUCTION Starch is a kind of low-costly renewable and biodegradable polymer and has been applied in academic research and industry for the past few decades. However, native starches was limited by their low thermal stability, susceptibility to extreme pH conditions, as well as strong retrogradation rate etc. Chemical modification is a classical way to effectively improve the functionalities of starch and makes it appropriate for various industrial uses. Oxidation as a form of chemical modification, involve the introduction of carboxyl and carbonyl functional groups, by means of subsequent depolymerization of the starch. .
