Background: Cinnamomum porrectum leaves, one kind of Cinnamomum family, has recently been used to produce a locally herbal tea. Although C. porrectum essential oil and aqueous extract have been reported to have some biological activities, including antioxidant, antimicrobial, and anti-inflammatory activities, there is no scientific data using the blanching process for the production of herbal tea. Therefore, this experiment aimed to study the effect of hot water blanching before drying process on microstructure, nutrition content of the tea powder, TPC, TFC, antioxidant activities of infusion, as well as the phenolic profile of the extract.Objective: To determine effect of hot water blanching process on nutritional value, microstructure, phenolic profile, and antioxidant activity of the C. porrectum herbal tea.Methods: The C. porrectum leaves were divided into 2 groups; control (un-treated) and blanched before dried for herbal tea processing. The fresh leaves and the powders of control and blanched leaves were checked for proximate composition and chlorophyll contents, in addition to color value. The powders were determined microstructure by SEM. The infusions were determined to have color value and total extractable phenolic and flavonoid contents, as well as antioxidant activities. The hydrolyzed extracts of freeze dried infusion were subjected to identify phenolic profile by HPLC. Results: The blanched tea powder yielded a percentage of fat and protein contents higher than untreated due to easier extraction because of the bigger pore size found in microstructure. Chlorophyll content of blanched was decreased compared with the control sample. However, it was found that blanching could greater maintain green color of both powder and infusion.Additionally, blanching helped increased TPC, TFC extractability, and antioxidant activities in all assays except metal chelating property. Based on retention time and peak profile determined by using HPLC, it was found that both control and treated extracts consisted of similar main phenolic and flavonoid compounds however, only kaempferol was found in un-treated. Moreover, hydrolyzed blanched extract showed a higher intensity of 2 unknown compounds than un-treated. Though un-treated provided a higher intensity of pyrogallol, gallic acid, and cinnamic acid, the blanched exhibited a higher intensity of caffeic acid, protocatechuic acid, p-coumaric acid, and rutin. Conclusion:Blanching before drying expanded pore size of dried leaves, increased yield extractability, maintained color value, chlorophylls and increased TPC and TFC which related to antioxidant activities. Blanched extract provided higher intensity of some phenolic compounds than un-treated.

Background: Cinnamomum porrectum (C. porrectum) is an aromatic medicinal plant from southern Thailand. While many Cinnamomum species demonstrate medicinal properties such as anti-inflammatory effects, some species are known to contain safrole, a group 2B carcinogen. Although the leaves of C. porrectum are used to produce herbal tea, there is no scientific data to support its properties as a functional food or any guarantee of its safety.Objective: To determine the effect of blanching before drying of C. porrectum leaves on their safrole content, phenolic profile, total phenolic content (TPC), and total flavonoid content (TFC), antioxidant and anti-inflammatory activities were compared to leaves dried with hot air.Methods: In the first part of the study, the leaves were dried in three conditions: freeze dried (F), hot air dried at 60 oC (C), and blanched for 60 seconds at 100 oC (B) before being dried at 60 oC until the moisture content reached 5-7% and then were ground and sieved to make powders. The F, C, and B were extracted by methanol and redefined as FM, CM, and BM, for the determination of their chemical constituents by GC-MS using C. porrectum wood oil (CWO) as the safrole standard. In the second part of the study, the C and B powders were analyzed for their proximate composition and were also used to make herbal tea infusions (CT and BT respectively) which were analyzed for their phenolic profile, TPC, TFC, antioxidant activities, cytotoxicity, and anti-inflammatory activity in RAW 264.7 cells.Results: Significantly decreased safrole contents of 89% and 82% were found in the BM sample when compared with CM and FM respectively. The CT and BT had similar phenolic profiles but different contents. The TPC, TFC, ABTS, and FRAP activities, in addition to cell viability and the nitric oxide inhibition of BT were higher than that of CT.Conclusion: The results demonstrate how blanching C. porrectum leaves before drying can decrease the safrole content when compared to freeze dried and hot air-dried leaves, thereby leading to a decrease of cytotoxicity in RAW 264.7 cells. Additionally, BT demonstrated a more intense phenolic profile, TPC, ABTS, and FRAP compared with the un-blanched control sample.Keywords: C. porrectum, freeze drying, hot air drying, blanching before drying, safrole, RAW 264.7 cells.