Extraction of Cinnamomum camphora chvar. Borneol essential oil using neutral cellulase assisted-steam distillation: optimization of extraction, and analysis of chemical constituents

Cinnamomum camphora chvar. Borneol essential oil (BEO) has potential biological activity and has attracted considerable interest. In this study, neutral cellulase assisted-steam distillation (NCSD) was first developed to extract BEO, followed by optimizing NCSD through single-factor test (SFT) and response surface methodology (RSM). The processing conditions of NCSD were optimized as follows: addition of neutral cellulase (0.36 FPU/g of fresh leaves), duration of enzymolysis (5.39 h), temperature (51.47 °C), and pH (6.15). The predicted yield of BEO using NCSD was 1.03% within 95% confidence intervals of the actual yield of BEO (1.03 ± 0.03%), which was 58% higher than the yield of BEO using conventional steam distillation (SD) without neutral cellulase pre-treatment (0.65 ± 0.04%). Moreover, chemical constituents of BEO using NCSD and SD were evaluated and compared. Results show that 62 volatile compounds were identified, and majority of functional compounds in the BEO using NCSD and SD were detected simultaneously, e.g. borneol, β-pinene, and β-cadinene. A significantly higher proportion of compounds with relatively lower molecular weight (MW) ranging from 130 to 150 and higher MW ranging from 205 to 225 were detected in the BEO using NCSD, which may contribute to a stronger flavoring impact and influence the overall flavor profile of the BEO. Therefore, significance of this study is to develop the NCSD as a more effective method than the SD for extracting the BEO from Cinnamomum camphora chvar. Borneol fresh leaves without compromising its quality and remaining the majority of chemical consitutents unchanged.