Variations in essential oil yield and composition during Cinnamomum cassia bark growth

To extract essential oil for industrial use, the yields and compositions of bark oil during Cinnamomum cassia growth (1-3 years old for the branch bark; 5-12 years old for the stem bark) were determined. The branch bark fraction had a higher essential oil yield than the whole branch. The essential oil yield from branch bark varied within 2.70-3.11% (w/w), while that from stem bark was 0.41-2.61% (w/w) due to differences in age and segment (top, center and lower) of the tree. There were 41 volatile compounds identified in bark oil, among which the majority presented high fluctuations in percentage of composition both in different growth stages and segments. Variations in oil yields did not present the same pattern as the percentages of trans-cinnamaldehyde. The results suggest that choosing bark according to trees' growth stages and separating stem barks into top, center and lower sections within a tree should significantly improve the extraction efficiency.

Research highlights▶ The yields of Cinnamomum cassia essential oil are affected by ages, parts (whole branches, branch bark and stem bark) and segments (top, center and lower) of the tree. ▶ 41 volatile compounds are identified in bark oil, and the percentage compositions are affected by ages and segments. ▶ Variations in oil yield do not present the same pattern as percentages of trans-cinnamaldehyde. ▶ Choosing the suitable material should significantly improve the extraction efficiency.