Changes in Bioactive Constituents in Black Rice Metabolites Under Different Processing Treatments

Area of Science:

• Food Science
• Metabolomics
• Nutritional Biochemistry

Background:

• Black rice (BR) is rich in bioactive compounds.
• Processing methods like milling, germination, and heat/pressure treatment can alter its composition.
• Understanding these changes is crucial for optimizing black rice products.

Purpose of the Study:

• To investigate the metabolic changes in black rice after different processing treatments.
• To identify key metabolites affected by milling, germination, and high-temperature/high-pressure (HTP) treatment.
• To provide a theoretical basis for improving black rice processing and product development.

Main Methods:

• Untargeted metabolomics analysis using liquid chromatography-mass spectrometry (LC-MS).
• Comparison of four black rice types: BR, milled black rice (MBR), wet germinated black rice (WBR), and HTP-WBR.
• Statistical analysis to identify differential metabolites and metabolic pathways (fold change ≥1.2 or ≤0.8333, p < 0.05, VIP ≥1).

Main Results:

• Significant variations in metabolic profiles were observed across the different processing groups.
• Milling led to the loss of bran-associated bioactive components like phenolic acids and anthocyanins.
• Germination reduced flavonoids and lipids but increased organic acids and amino acids.
• HTP treatment enhanced heat-stable flavonoids and polyketides and promoted fatty acid beta-oxidation.

Conclusions:

• Processing significantly alters the metabolomic profile of black rice.
• Specific processing steps have distinct effects on key bioactive compounds.
• Findings support optimizing processing techniques for enhanced nutritional and functional properties of black rice.