Optimizing processing parameters to produce a novel spray dried hydrolyzed rice-derived ingredient using response surface methodology

Rice flour (RF), a common rice product, has become an increasingly sought out ingredient for its blend flavor and gluten-free nature. However, the high concentration of native starch (> 80%) represents a technological challenge for its incorporation into food formulations, especially due to its low solubility, which may limit its food industry applications. This study shows the enzymatic hydrolysis of rice flour starch followed by optimized spray drying using protein-rich drying carriers (rice protein concentrate RPC, soy protein isolate SPI) to produce a novel, enhanced hydrolyzed rice-derived ingredient (HRI). For this, white RF suspension (25% w/v) was treated with α-amylase (70 °C, 30 min) and amyloglucosidase (50 °C, 30 min) to produce a hydrolyzed solution that was spray dried using a 3³ Box-Behnken design to maximize solids recovery (%) and sugars recovery (%). Optimal conditions (10°Bx, 13.4% w/v carrier addition and 35.5:64.5% SPI:RPC) led to high solids (63.4%) and sugar recoveries (82.6%), indicative of an efficient spray drying process. Spray dried HRI showed low water activity (0.187 ± 0.001) and enhanced functional properties compared to unprocessed RF, including increased solubility (54.07 ± 0.85%), higher flowability and emulsifying attributes. Overall, we show a successful production protocol using industrially friendly techniques to obtain a novel rice-derived ingredient for food applications. These advancements pave the way for developing high-performance, stable rice starch-derived ingredients, driving innovation and expanding opportunities in food formulation and processing.