High pressure processing at different hydration levels as a tool to enhance rice bran stability and...

Area of Science:

• Food Science and Technology
• Food Processing
• Microbiology

Background:

• High-pressure processing (HPP) is recognized for enhancing food safety and shelf life.
• Its efficacy in low-humidity environments and impact on rice bran (RB) properties remain underexplored.

Purpose of the Study:

• To evaluate the microbial effectiveness of HPP on rice bran (RB) across various hydration levels.
• To investigate the effects of HPP on the techno-functional and physicochemical properties of RB.

Main Methods:

• Rice bran (RB) samples were subjected to HPP at 500 MPa for 15 min at hydration levels of 15%, 30%, 60%, and 77%.
• Microbial counts (mesophilic bacteria, molds, yeast, spores) and techno-functional/physicochemical properties (dietary fiber, protein solubility, peroxide value, emulsifying activity) were analyzed.

Main Results:

• HPP significantly reduced mesophilic bacteria, molds, and yeast at >15% hydration, with reductions up to 4 log cycles.
• Spore inactivation was not significantly affected by HPP. Particle aggregation and honeycomb formation occurred at ≥30% hydration.
• Soluble dietary fiber increased at 15% hydration. Protein solubility improved with hydration. Peroxide values decreased at ≤30% hydration but increased at >30% hydration.
• Emulsifying activity decreased at ≥60% hydration, yet HPP enhanced emulsion stability.

Conclusions:

• HPP is effective for microbial reduction in rice bran (RB) at moderate to high hydration levels, with varied impacts on techno-functional and physicochemical properties.
• HPP shows promise for improving rice bran (RB) utilization in food applications, particularly when considering hydration-dependent effects.