In order to utilize rice flour in food systems with high water content, rice flour was dispersed into water to prepare a rice flour suspension and emulsion. Stability of the suspension was significantly increased by heating processes in combination with homogenization processes. The improved stability was probably due to finely dispersed rice flour particles (-10microm) and gelatinized starch granules. Since oil droplets with a size of several micrometers disperse in an aqueous phase of many real food emulsions, rice flour is expected to be utilized as a fat replacer mimicking oil droplets. Emulsions were prepared dispersing soybean oil into a rice flour suspension. The emulsion was relatively stable to oil droplet coalescence for 7 days. Starch and proteins such as 10-16 kDa prolamin adsorbed to oil droplet surfaces to stabilize the emulsion. These results suggest that rice flour is expected to be utilized as a natural emulsifier in the food industry.

In order to contribute to the development and improvement of green sample preparation techniques, a new special approach combining the principles and advantages of microextraction techniques, hydrolytic enzymes and ultrasonic radiation power is presented. This new approach is called as ultrasound assisted-enzyme based hydrolytic water phase microextraction method (UA-EH-WPME). In this study, We developed and used a solvent-free UA-EH-WPME method as innovative, green and simple sample preparation method for the extraction of arsenic (As) in rice and flour samples prior to Inductively Coupled Plasma–Mass Spectrometer (ICP-MS) determination. The UA-EH-WPME method based on the extraction of total As in 10.0 mg of food samples to 300 µL of pH 7.0 aqueous phase with the help of the 3.0 mg of α-amylase in as little as 5 min. In this method, α-amylase acts as a bond breaker agent to break down certain bonds of bio-molecules in food matrix, which lead to extraction of As from food matrix to aqueous phase. 1568A Rice Flour certified reference material was used to optimize the important analytical parameters, which were type of hydrolytic enzyme, pH, volume of aqueous phase, amount of enzyme, temperature of extraction medium and time of ultrasonic radiation, for the quantitative extraction of As from food matrix to aqueous phase. This innovative solvent-free method leads to emerge new ideas in the sample preparation field, by using the benefits of microextraction techniques, hydrolytic enzymes and ultrasonic radiation power, such as elimination of the toxic solvent usage, necessity of mg level of enzyme and food samples, very short and simple extraction process. The LOD, inter-day RSD and intra-day RSD values for the developed UA-EH-WPME/ICP-MS procedure were found as 27.3 µg kg⁻¹, 4.27% and 6.13%, respectively.