Microwave Impact on the Flavour Compounds of Cinnamon Bark (Cinnamomum Cassia) Volatile Oil and Polyphenol Extraction

Background: Recent developments in extraction techniques of natural materials for the value added compounds viz., pigments, volatile oil, bioactive compounds include application of ultra sonication, high pressure extraction, pulsed electric field application, microwave-assisted extraction and enzyme assisted extraction. Essential oil & bioactive compounds from spices are gaining lot of importance recently in view of the health benefits they posses. Enhanced extraction of cinnamon volatile oil by one of the emerging technologies viz., microwave application and its impact on flavour compounds and polyphenols is aimed at in this paper. Methods: Microwave treatment of cinnamon powder in water at varying powers viz., 100, 200, 300W and time 1-7 min. was carried out followed by hydro distillation for volatile oil extraction and solvent extraction fro polyphenol extraction. The physico-chemical quality of the oil obtained by microwave treatment was studied by measuring optical rotation, refractive index, specific gravity and GC profile. Conclusion: Microwave treatment for 5 minutes yielded highest yield of oil (3.09%) as against (2.34%) by conventional hydro distillation. Microwave treatment for 7 min yielded 3.08 % oil. The percentage recovery of oil was 72.7 % in the first hour of hydro distillation for 7 min microwave treatment, as against 54.5 % in the first hour for 5 min treatment. Microwave treatment of cinnamon resulted in enhanced extraction of volatile oil (32%), cinnamaldehyde (38%) the bio-active compound of cinnamon oil and polyphenols (11-31%). The rate of extraction of volatile oil with 5 min microwave pre-treatment followed first order kinetics with a rate constant value (k) 0.0131×10-3/min. of cinnamon volatile oil.