Modification of cassava starch by ozone aiming its capacity expansion in oven

• Grant number: 13/07748-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2013
• End date: July 31, 2014
• Field of knowledge: Agronomical Sciences - Food Science and Technology
• Principal Investigator: Silene Bruder Silveira Sarmento
• Grantee: Jaqueline Barduco
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The starch extracted from vegetables is an important food ingredient due to its physico-chemical and functional properties, inherent to each botanical source. In addition, it is possible to modify the starch altering its properties and molding it for other types of applications. Among the modification processes is oxidation, which causes changes in the molecular structure of the polysaccharide resulting in functional properties such as the ability to form slurries with high solids, high transparency and resistance to retrogradation and in the specific case of cassava starch it can also promote capacity of expansion in oven. During processing of sour starch (polvilho azedo), after a natural fermentation process, the starch is oxidated by ultraviolet radiation. The final product acquires the ability to expand in oven. This distinctive feature of this starch is highly variable, depending on the natural conditions of their processing, mainly solar drying. The oxidation of starch by chemical agents could be used in order to standardize the expansion property. The uniformity would be important for the industries that use this raw material for the production of biscuits, cheese breads or even expanded products for coeliacs. Most studies in the literature about oxidation of starch use sodium hypochlorite and hydrogen peroxide. These reagents, however, can also generate waste (agro-industrial residues) and also residues in food. As these products use starch as the main ingredient, this could lead to restrictions on use, because they are chemically modified. The oxidation by ozone is considered a "green" technology do not generating these same inconveniences, presenting itself as a sustainable way out for this modification. Thus the aim of this study is to evaluate the physico-chemical and functional characteristics of cassava starch after oxidation by ozone mainly targeting expansion in the oven.