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

• Published in: Foods Vol. 14; no. 9; p. 1630
• Main Authors: Hong, Bin, Zhang, Shan, Yuan, Di, Shan, Shan, Zhang, Jing-Yi, Sha, Di-Xin, Chen, Da-Peng, Yin, Wei-Wei, Lu, Shu-Wen, Ren, Chuan-Ying
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 05.05.2025; MDPI
• Subjects: Acids; Amino acids; Anthocyanins; Antioxidants; Benzenoids; Biological activity; black rice (BR); Chromatography; Dietary fiber; Dietary minerals; Enzymes; Fatty acids; Flavonoids; Germination; Grain; Heat; High temperature; high temperature and pressure (HTP); Ions; Lipid metabolism; Lipids; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Metabolic pathways; Metabolism; Metabolites; Metabolomics; Micronutrients; milling; Negative ions; Organic acids; Oxidation; Phenolic acids; Phenylpropanoids; Phytochemicals; Polyketides; Positive ions; Product development; Rice; Thermal stability; United Kingdom > UK; germination; high temperature and pressure (HTP); metabolomics; black rice (BR); milling
• ISSN: 2304-8158; 2304-8158
• DOI: 10.3390/foods14091630

In this study, liquid chromatography–mass spectrometry (LC-MS) was employed to conduct untargeted metabolomics analysis on black rice (BR), milled black rice (MBR), wet germinated black rice (WBR), and high-temperature and high-pressure-treated WBR (HTP-WBR). A total of 6988 positive ions and 7099 negative ions (multiple difference ≥1.2 or ≤0.8333, p < 0.05, and variable importance in projection ≥1) were isolated, and 98 and 100 differential metabolic pathways were identified between the different samples in the positive and negative ion modes, respectively. Distinctive variations in the metabolic compositions of BR, MBR, WBR, and HTP-WBR were observed. Flavonoids, fatty acids, lipids, phenylpropanoids, polyketides, benzenoids, and organooxygen were the dominant differential metabolites. Milling removed the majority of bran-associated bioactive components such as phenolic acids, anthocyanins, micronutrients, fatty acids, antioxidants, and dietary fiber. The germination process significantly reduced the number of flavonoids, polyketides, and lipid-related metabolites, while enzymatic activation notably increased the number of organic acids and amino acids. HTP treatment synergistically enhanced the content of heat-stable flavonoids and polyketides, while simultaneously promoting fatty acid β-oxidation. These findings establish novel theoretical foundations for optimizing processing methodologies and advancing functional characterization in black rice product development.