Functional Properties of Insoluble Dietary Fiber Obtained from Ceylon Cinnamon (Cinnamomum zeylanicum or Cinnamomum verum) Spent Bark Waste

Cinnamon spent bark waste (CBW) is the residue resulted after cinnamon oil extraction. It is accumulated in high quantities in cinnamon oil distillation plants and creates disposal problems. The aim of this study was to extract dietary fiber (DF) from CBW using aqueous, chemical and enzymatic methods and evaluate the functional properties of resulted fiber. CBW reported a very low content of soluble dietary fiber (SDF) but significantly higher (p<0.05) insoluble dietary fiber (IDF) content (0.84 % and 78.86 % respectively). Therefore, only the IDF fraction was extracted and functional properties including water holding capacity (WHC), water swelling capacity (WSC), oil holding capacity (OHC) and glucose adsorption capacity (GAC) were determined. Chemical and water extraction methods resulted the significantly lowest (70.92 %) and highest (93.87 %) DF yields (p<0.05) respectively. Chemical extraction produced DF with significantly higher (p<0.05) WHC (3.91 g/g) compared to CBW (3.29 g/g). Moreover, DF obtained by enzymatic extraction reported significantly higher (p<0.05) WSC (0.90 mL/g) than CBW (0.17 mL/g). All the extraction methods produced fiber with significantly higher (p<0.05) OHC compared to the original samples. Chemically extracted fiber reported the significantly highest (p<0.05) OHC (3.6 g/mL) compared to the other fiber products. GAC of fiber extracted by chemical (0.86 mmol/g) and enzymatic (0.35 mmol/g) treatments were significantly higher (p<0.05) than that of water (0.08 mmol/g) extracted fiber and original samples. Results suggested that though the yield of DF was low, functional value of DF obtained by chemical extraction is better than enzymatic and water extraction methods.