Influence of extraction method on yield and purity of rice starch

After preliminary tests to select a single or double maceration, effect of extraction solution, soaking time and temperature and their interactions were assessed to improve rice starch extraction. A 23 factorial experimental design was used with NaOH 0.2% and Na2S2O5 0.3%, time levels of 6 and 10 h, temperature levels of 30°C and 50°C, taking starch yield and residual proteins as deciding factors. Yield was not influenced by all the factors investigated or their interactions, while residual protein was strongly influenced. Further trials with more concentrated extraction solution, at 25°C for 12 h were performed to verify the trend of previous results.