Superheated water extraction (SWE), is a novel method, used to extract proteins or other bioactive component from agriculture products. Methods: In this study, the extract from quinoa-barley malt (in a proportion of 30:70) was treated by SWE method. The effect of extraction time (15, 30, and 45 min) on physicochemical and functional properties of the extract was determined at 120 ºC. Results: The result showed that by increasing the extraction time the amount of protein increased. The maximum protein (%) was obtained in 45 min of SWE. The results revealed that increasing the extraction time had a significant effect on the turbidity and pH. In addition, increasing the extraction time had a positive effect on the functional properties. The highest protein isolate (PI) solubility was at 120 °C. Conclusions: Although SWE method appears to be a useful extraction method for producing valuable materials from cereal and pseudocereal, this method has only been used at pre-commercial scale and more investigation is required to study the quantity, quality, and stability of the extracted valuable materials to scale it up for industrial means.

Background: Subcritical water extraction (SWE) is a friendly technique applied to produce rice by-product extract. The aim of this study is using SWE as a new friendly extraction method for producing protein isolates (PI) of rice bran and rice combination as a byproduct of Iranian agriculture product. Methods: D-optimal combined design was used to optimize bran rice ratio, solid/water ratio, extraction time, and particle size to obtain maximum protein. Bran (8-12%) and rice ratio (88-92%) solid water (0.04 -0.12%), time (15-45 min), and particle sizes (420 µm and 710 µm) were selected as independent variables, and protein as dependent variable. After optimization, the effects of extraction parameters on functional properties were investigated. Results: Increasing bran/rice ratio has a significant effect on the protein extraction. In this study, the optimum SWE conditions were solid water (0.12), bran rice ratio (8:92), time (45 min), particle size (420 µm), and the optimum SWE temperature was obtained at 120 Cº. SWE also could significantly enhance functional properties, such as the solubility, emulsifying activity index (EAI), and degree of hydrolysis of by-product of rice milling (BRM) PI. Conclusion: According to the positive impact of SWE on protein extraction and the functional properties of BRM PI, this method could be applied as a novel extraction technique to modify the properties of rice protein isolate for functional purposes in the future. However, more investigation is required to study the quantity and quality of the extracted valuable materials to scale it up for industrial means.