Processing-Induced Variations in Bamboo Leaf Powder: Effects of Fixation Methods on Color Stability, Volatile Compounds, and Sensory Profiles

Fixation is a necessary step in bamboo leaf powder processing and plays a decisive role in determining its color, aroma, and taste. It is irreplaceable for maintaining quality, stability, and forming unique sensory characteristics. In this study, optimal conditions for steamed bamboo leaf powder (SBL), baked bamboo leaf powder (BBL), and blanched bamboo leaf powder (BCBL) were determined by measuring chlorophyll content, color parameters, and enzyme inactivation. In addition, volatile organic compounds (VOCs) in bamboo leaf powder processed with different fixation methods were analyzed using gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), and relative odor activity value (ROAV). Steaming for 120 s, baking for 60 s, and blanching for 30 s effectively preserved color, with a* values of -1.37, -1.44, and -1.62, all superior to untreated bamboo leaf powder (UBL). Among them, BCBL showed the best color stability, with the lowest color difference (ΔE = 0.66) compared with fresh bamboo leaves (FBLs). Results showed that BBL retained the highest VOC abundance (15.67% of FBLs), followed by SBL (5.73%) and BCBL (5.48%). Hexanal, nonanal, linalool, and α-ionone were identified as key aroma contributors, forming green, fresh, and floral notes. Sensory differences were evident: SBL exhibited strong seaweed-like and roasted notes, BCBL showed partial loss of characteristic aromas, while BBL preserved grass, fruity, and woody attributes. These findings highlight the significant influence of fixation methods on aroma-active compounds and color stability, providing a theoretical basis for producing bamboo leaf powder with superior sensory quality.