Integrated non-targeted metabolomics and transcriptomics reveals the browning mechanism of scraped ginger (Zingiber officinale Rosc.).

Ginger (Zingiber officinale Rosc.) possesses a rich nutritional profile, making it a valuable ingredient for a wide range of culinary applications. After removing its outer skin, ginger can be effectively utilized in the production of pickles and other processed food products. However, following scraping, ginger undergoes a series of physiological and biochemical changes during storage, which can impact its subsequent development and utilization in food. Thus, the current study aimed to investigate the browning mechanism of scraped ginger using non-targeted metabolomics and transcriptomics. The findings revealed 149 shared differential metabolites and 639 shared differential genes among freshly scraped ginger, ginger browned for 5 days, and ginger browned for 15 days. These metabolites and genes are primarily enriched in stilbenes, diarylheptane, and gingerol biosynthesis, phenylpropanoid biosynthesis, and tyrosine metabolism. Through the combined regulation of these pathways, the levels of phenolic components (such as chlorogenic acid and ferulic acid) and the ginger indicator component (6-gingerol) decreased, whereas promoting an increase in the content of coniferaldehyde and curcumin. Additionally, the activities of polyphenol oxidase (PPO) and peroxidase (POD) were significantly increased (p-adjust <0.05). This study hypothesized that chlorogenic and ferulic acid undergo polymerization under the catalysis of PPO and POD, thereby exacerbating the lignification of scraped ginger. These findings offer a theoretical foundation for understanding the browning mechanism of ginger after scraping. PRACTICAL APPLICATION: Ginger's quality and nutrition can change when its skin is removed. This happens due to physical and biochemical reactions during scraping. The browning that occurs affects both the taste and health benefits of ginger, we can better understand how to prevent browning and maintain ginger's quality. This research sheds light on improving ginger processing techniques for better products.