Effect of biodegradation by Lactic Acid Bacteria on physical properties of cassava starch

Sour cassava starch is used as main ingredient in the manucfacture of food that can expand when baked. Lactic acid fermentation has been known to be responsible for the baking expansion properties. Many strains of lactic acid bacteria with different ability to degrade starch has been isolated and used as starter culture in this study. The fermentation effect was investigated with the purpose of establishing a relation between physicochemical changes on cassava starch granule and functional properties of starch. Some lactic acid fermented samples presenting baking property have been compared with lactic acidified and native cassava starch. All the samples were analyzed for its thermal properties and starch granule structure by using Differential Scanning Calorimeter and Scanning Electron Microscopy, respectively. Samples of fermented cassava starch have a higher baking expansion character (8.54-11.51 ml/g) than native starch (6.61 ml/g), which were associated with its lower gelatinization enthalphy and peak gelatinization temperature. The starch granule of all fermented and acidified samples had lost their surface smoothness due to external corrosion and provided a greater extent of starch modification.