1) Agricultural and Food Engineering Department, Indian Institute of Technology, Kharagpur, West Bengal – 721302, India; 2) Department of Agricultural Processing and Food Engineering, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha – 751003, India; 3) Post Harvest Process and Food Engineering, College of Agriculture, Jawaharlal Nehru Agricultural University, Tikamgarh, Madhya Pradesh – 472001, India; 4) Department of Horticulture, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha – 751003, India
Manisha1), Kalpana Rayaguru2), Lalit Mohan Bal3), Sonali Das2), Sanjaya Kumar Dash2), Subash Chandra Swain4)
Sarpagandha (Rauwolfia serpentina) root of Grade 1 (G1) and grade 2 (G2) of 6, 12 and 18 months maturity stages were dried using four different drying methods viz. sun drying (SD), shade drying (SHD), solar drying (SLD) and hot air drying (HAD 50°C, HAD 60°C, HAD 70°C). Drying characteristics for different drying methods, root grade and maturity stage have been explored and their influence on moisture ratio versus drying time was assessed using an ANN model. The phytochemicals such as total phenolic content (TPC), flavonoid, ascorbic acid and tannin as well as the antioxidant activity of all the dried samples have been evaluated. Drying time requirement for sarpagandha roots to achieve final moisture content of about 4.0 to 6.95% d.b. varied between 150–750 mins for HAD and 4–15 days for traditional drying (SD, SHD, SLD) methods also Grade 1 samples took more time than grade 2 samples irrespective of drying methods and maturity stage. The ANN model using logsig and transig transfer functions could best predict the moisture ratio vs drying time (R2=0.999) for HAD and (R2=0.995) for traditional methods respectively. The study revealed that the samples of 18 months maturity possessed maximum amount of all the bioactive compounds and antioxidant activities. Among the hot air drying, the samples dried at 60°C and among the traditional methods, the shade dried samples could retain significantly higher amount of most of the phytochemicals and antioxidant properties.
Keywords: Drying, maturity stage, kinetics, artificial neural network, phytochemicals
Arch Lebensmittelhyg 74,
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