Enhancing GABA and Antioxidant Bioaccessibility in Germinated Brown Rice: Ultrasonic-Assisted Cellulase Pretreatment Optimized via RSM and ANN-GA.

Germinated brown rice (GBR) is a functional food rich in γ-aminobutyric acid (GABA) and antioxidants. However, its bioaccessibility is limited by the dense bran structure. Ultrasonic-assisted enzymatic pretreatment has emerged as a green technology to enhance the nutritional profile of germinated grains. In this study, we optimized ultrasonic-assisted cellulase pretreatment for GBR to enhance the GABA content and antioxidant activity. Process variablesultrasonic time and cellulase concentrationwere modeled using response surface methodology (RSM) and artificial neural network-genetic algorithm (ANN-GA). The ANN-GA model demonstrated higher predictive accuracy compared to RSM. Under optimized conditions, the GBR exhibited increased levels of GABA, total phenolics, and antioxidant activity, alongside a reduction in the optimal cooking time. In vitro digestion further revealed improved bioaccessibility of GABA and total phenolic content (115.74% and 128.53%, respectively). This approach presents a sustainable, scalable strategy for producing GBR-based functional foods with enhanced health benefits and processing efficiency.