Effect of germination and high pressure treatments on brown rice flour rheological, pasting, textural, and structural properties

Brown rice (BR) and brown rice germinated (GBR) for different times (0 hr, BR; 5 hr, GBR5; 9 hr, GBR9) were high pressure (HP) processed at 200-600 MPa for 10 min. Swelling, rheological, pasting and textural properties, and microstructural changes that are important in the cooking quality of BR flour were investigated. Germination and HP contributed to restricting swelling. The germination treatment induced more severe HP modifications. The 10 min treatment at 400 MPa was found to be the most desirable HP condition. Besides, the germination process reduced the viscosity and hardness, while HP resulted in enhancing them. Further, the setback and break down pasting property values decreased after germination and HP. Changes in starch granule size and flour structure due to germination might be responsible for the different effects of HP among samples. The results from this study can help to design diversified GBR-based products with enhanced cooking qualities. Practical applications Consumers are interested in brown rice (BR) because of its high nutritive value with multiple bioactive components and leading to health benefits. Basing on a systematic evaluation of germination and high pressure (HP) treatments effects on swelling, rheological, pasting, textural and structural properties of BR flour, this study not only developed new modification methods for promoting rheological behavior of BR flour, but also provided opportunities for better use BR flour as the principal material for developing new food products for particular requirements. Results showed that germination and HP treatment conditions can be selected to obtain flour with desirable characteristics for specific consumer/producer demand.