Biotechnological Communication Biosc.Biotech.Res.Comm. Vol 13 (2) April-May-June 2020 Pp-781-786 Investigations on the Processing and Production of Herbal Tea from Pakalana Telosma cordata, Flowers using Blanching and Drying Minh Phuoc Nguyen Faculty of Biotechnology, Ho Chi Minh City Open University, Ho Chi Minh City, Vietnam ABSTRACT Tea is one of the most popularly consumed beverages worldwide. Pakalana (Telosma cordata Merrill) or Thien Ly flower as a valuable crop in different rural areas of Vietnam. It has a great amount of phytochemical components beneficial for human health. It can be converted into herbal tea like a healthy drink. There is not any literature mentioned to tea processing from the Pakalana (Telosma cordata Merrill) flower. Therefore objective of this study focused on the effect of citric acid concentration (0.05, 0.1, 0.15, 0.2, 0.25%) in blanching; vacuum drying temperature (40oC, 45oC, 50oC, 55, 60oC) and pressure (-0.2, -0.4, -0.6, -0.8, -1.0 bar) to total phenolic content (mg GAE/g), antioxidant activity (μM Fe2+/g) and organoleptic attribute (sensory score) of the dried pakalana flower tea. Results showed that pakalana flower should be blanched in hot water o95 C at 5 seconds in the present of citric acid 0.2% and then being dried by vacuum dryer at 50oC, -0.8 bar for 6 hours to get the final moisture content below 10.0% available for preservation. Pakalana flower could be utilized as an appropriate material for processing one kind of functional food. KEY WORDS: PAKALANA FLOWER, BLANCHING, vacUUM DRYING, HERBAL TEA, TOtal PHENOLIC, ANTIOXIDANT activitY. INTRODUCTION fragrance plant (Widodo, 2014). The flowers are very fragrant, peduncle 0.5-1.5 cm, puberulent (Shakun and The genus Telosma includes three species, Telosma Shivani, 2019). This plant was popular for its flower as cordata, T. pallida and T. puberula (Michele and Manop, vegetable with great antimicrobial property (Krasaekoopt 2019). Telosma cordata or Thien ly is grown as a valuable and Kongkarnchanatip, 2005). The leaves are good crop in different rural areas of Vietnam. It is a perennial source of essential oils as well as exhibit many medicinal vine propagating from rooted stem cuttings and growing properties for ailments such as wound, scaby, ulcer, on trellises of various kinds (Dau et al., 2008). Pakalana headache. Flower buds have normally been consumed (Telosma cordata Merrill) flower was cultivated as floral stir-fried or boiled. They were used in cooking and medicinally to treat conjunctivitis. At 21oC and 24oC, ARTICLE INFORMATION inflorescence initiation of pakalana flower occured after 3 weeks and the clusters grew to 6 mm in another 2 weeks *Corresponding Author: [email protected] (Criley 1995). Geraniol, beta-ionone, dihydro-beta-ionone, Received 12th April 2020 Accepted after revision 23rd May 2020 dihydro-beta-ionol, and cis-and trans-theaspirane were Print ISSN: 0974-6455 Online ISSN: 2321-4007 CODEN: BBRCBA major volatile components of Pakalana (Telosma cordata Thomson Reuters ISI Web of Science Clarivate Analytics USA and Crossref Indexed Journal NAAS Journal Score 2020 (4.31) SJIF: 2020 (7.728) A Society of Science and Nature Publication, Bhopal India 2020. All rights reserved Online Contents Available at: http//www.bbrc.in/ 781 DOI: 10.21786/bbrc/13.2/60 Nguyen Merrill) flower (Arai et al., 1993). Extract of pakalana in the dried pakalana (Telosma cordata Merrill) flower (Telosma cordata Merrill) flower has a great antidiabetic tea: Raw Pakalana (Telosma cordata Merrill) flowers were potential (Lilibeth and Edna, 2014). blanched in hot water with 0.2% citric acid at 95oC in 5 seconds. Then these samples would be dripped and dried Edible flowers have valuable phytochemical constituents under vacuum dryer at different temperature (40oC, 45oC, with abundant antioxidant activities. Phenolics are 50oC, 55oC, 60oC) and different pressure (-0.2, -0.4, -0.6, a substantial and diverse group of phytochemicals -0.8, -1.0 bar) for 6 hours. All samples were analyzed (Ngoitaku et al., 2016). Phenolics are responsible for total phenolic content (mg GAE/g), antioxidant activity antioxidant characteristics related to their capabilities (μM Fe2+/g), organoleptic attribute (sensory score) to to scavenge free radicals, break radical chain reactions select the optimal drying condition. and chelate metals. They are correlated with a reduced risk of cardiovascular disease and cancers (Huang et al., Phytochemical, sensory analysis: The total phenolic 2010). Herbal teas are infusions made from fruits, leaves, content (TPC, mg GAE/g) was estimated as gallic acid flowers, roots and stems of plants and are intended for equivalents by the Folin–Ciocalteu reagent method oral aqueous consumption (Malongane et al., 2018). (Djeridane et al., 2006). An extract of 1 mL from Pakalana Herbal teas contribute extremely strong taste, relaxation, was mixed with 5 mL of Folin-Ciocalteu reagent in a test rejuvenation with different therapeutic and energizing tube and kept at ambient temperature. After 10 min, 4 benefits (Chandini, 2014; Joubert et al., 2017; Florence mL of 7.0% (w/v) Na2CO3 and the mixture was left for et al., 2020; Quang and Hoang, 2020). reaction at ambient temperature in a dark place for 30 minutes. The absorbance of the reacted mixture was then Production of tea has been broadly investigated on measured at 765 nm using a spectrophotometer. The total variety of materials such as chamomile, ginger, ginseng, phenolic content of the extracts was expressed as mg peppermint, cinnamon, roselle etc. However, the research gallic acid equivalent (mg GAE) based on the standard on production of edible flower tea from pakalana flower curve of gallic acid solutions. has been rarely reported. Therefore purpose of this study focused on the citric acid concentration in blanching The antioxidant activity (FRAP, μM Fe2+/g) was measured and vacuum drying temperature and pressure to total by ferric-reducing antioxidant power (Benzie and Strain, maintain the phenolic content, antioxidant capacity and 1996). The FRAP reagent was prepared by mixing acetate organoleptic property of pakalana flower, to be used as buffer (250 mM, pH 3.5), a solution of 10 mM TPTZ in 40 tea a popular functional herbal drink. mM HCl, and 20 mM FeCl3 at 10:1:1 (v/v/v). The reagent (3.400 μL) and sample solutions (100 μL) were added to MATERIAL AND METHODS each well and mixed thoroughly. The absorbance was taken at 593 nm after 30 minutes. Organoleptic attribute Pakalana (Telosma cordata Merrill) flowers were collected (sensory score) of pakalana (Telosma cordata Merrill) from Soc Trang province, Vietnam. After collecting, they flower was assessed by a group of 11 panelists using must be quickly conveyed to laboratory for experiments. the 9-point Hedonic scale. The fresh edible flowers were cleaned under tap water to remove foreign matters; the petals were separated Statistical analysis: The experiments were run in and kept at room temperature to drain. Petals were triplicate with three different lots of samples. The data blanched and dried under different conditions. Chemical were presented as mean±standard deviation. Statistical substances and reagents such as Folin-Ciocalteu reagent, analysis was performed by the Statgraphics Centurion sodium carbonate, gallic acid standard, acetate buffer, XVI. TPTZ , HCl, FeCl. 6H2O were all analytical grade supplied from Rainbow Trading Co. Ltd., Vietnam. RESULTS AND DISCUSSION Effect of citric acid concentration in blanching to total Effect of citric acid concentration in blanching to total phenolic content (mg GAE/g), antioxidant activity phenolic content (mg GAE/g), antioxidant activity (μM (μM Fe2+/g) and organoleptic attribute (sensory score) Fe2+/g) and organoleptic attribute (sensory score) in the in the dried pakalana (Telosma cordata Merrill) flower dried pakalana (Telosma cordata Merrill) flower tea: tea: Raw pakalana (Telosma cordata Merrill) flowers In our reseach, raw pakalana (Telosma cordata Merrill) were blanched in citric acid solution (0.05, 0.1, 0.15, 0.2, flowers were blanched in citric acid solution (0.05, 0.1, 0.25%) at 95oC, 5 seconds. Then they were dripped and 0.15, 0.2, 0.25%) at 95oC, 5 seconds. Then they were dried by vacuum dryer at 40oC, -0.2 bar for 6 hours by dripped and dried by vacuum dryer at 40oC, -0.2 bar for vacuum dryer. Then they were analyzed total phenolic 6 hours by vacuum dryer. Then they were analyzed total content (mg GAE/g), antioxidant activity (μM Fe2+/g), phenolic content (mg GAE/g), antioxidant activity (μM organoleptic attribute (sensory score) to choose the best Fe2+/g), organoleptic attribute (sensory score) to validate citric acid concentration in blanching. the appropriate blanching condition. Results were mentioned in figure 1-3. From figure 1-3, the pakalana Effect of vacuum drying temperature and pressure to (Telosma cordata Merrill) flower should be blanched at total phenolic content (mg GAE/g), antioxidant activity 95oC in 5 seconds in the presence of 0.2% citric acid to (μM Fe2+/g) and organoleptic attribute (sensory score) maintain the most total phenolic content, antioxidant 782 PROCESSING AND PRODUCTION OF HERBAL TEA BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS Nguyen capacity and organoleptic attribute in the dried pakalana of citric acid in the blanching medium resulted in higher (Telosma cordata Merrill) flower tea. total phenolic retention and antioxidant activity than the usage of water only. This result was similar to other findings in blanching white saffron (Pujimulyani et al. 2010), corn (Randhir et al., 2008), wheat (Cheng et al., Figure 1: Effect of citric acid concentration (%) in 2006). It was presumed that in blanching process, the blanching to total phenolic content (mg GAE/g) in the dried antioxidants in the form of glycoside were hydrolized pakalana (Telosma cordata Merrill) flower tea into aglikon and sugar (Yue and Xu, 2008). The blanching of pakalana flower increased antioxidant activity.