Convective dehydration kinetics of noodles prepared from taro (Colocasia esculenta), rice (Oryza sativa) and pigeonpea (Cajanus cajan) flours

Drying characteristics of noodles prepared from 50% taro and remaining equal proportions of rice and pigeonpea flours were investigated in a convective type dryer for a temperature range of 50°C to 80°C at a constant air velocity of     1.5 m s-1.  Results indicated that drying took place in falling rate period.  The sample dried at 50°C was found better in color as compared to samples at 60°C, 70°C and 80°C.  The rehydration weight of noodles decreased with the increase in drying temperature.  Moisture transfer from noodles was described by applying Fick’s diffusion model and the effective moisture diffusivity was calculated.  Effective moisture diffusivity increased with increase in temperature.  An Arrhenius relation with activation energy of 38.53 kJ mol-1 expressed the effect of temperature on moisture diffusivity.  Mathematical models were fitted to the experimental data and the performance of these models were evaluated by comparing the coefficient of determination (R2), Root mean square error (RMSE), reduced chi-square (χ2), percent mean relative deviation modulus (E%) between observed and predicted moisture ratio.  Verma model gave the best results for describing the drying behaviour of noodles.   Keywords: noodle, taro, dehydration kinetics, temperature, moistur

Effect of process parameters on the antioxidant activities of bioactive compounds from Harad (Terminalia chebula retz.) Shilpa Soni, H.K. Sharma*, Pragati Kaushal and C. Singh Food Engineering & Technology Department, Sant Longowal Institute of Engineeri

Terminalia chebula retz (T.Chebula) is a herb known as king of medicinal plants in ayurvedic world. Presence of large number of phytoconstituents makes T.Chebula a potential source of nutraceuticals and can become cynosure of modern nutraceutical world. The objective of this study was to optimize the extraction conditions for bioactive constituents from T.Chebula fruits using Response Surface Methodology (RSM). A central composite face centered design (CCD) was employed. The extraction conditions for bioactive constituents from T. Chebula fruits were optimized by using three independent process variables i.e. methanol concentration, 50-90%, extraction temperature, 50-70°C and extraction time, 30-60 min. Effect of extraction parameters was found to be significant. The optimum extraction conditions were identified as 90% methanol concentration, 70°C temperature and 59.94 minutes for maximum total phenolic content(TPC), 3.87 GAE mg/g, total flavonoid content (TFC), 361.37 CE mg/g, total antioxidant activity(TAA), 0.158 AAE mM/g and α,α-diphenyl-β-picrylhydrazyl (DPPH) scavenging activity (DSA), 86.28 %. Experimental values for response variables under the optimum conditions were found reasonably close to the predicted value. GC–MS analysis of methanol extract of T.Chebula fruits under the optimum conditions led to the identification of 7 major bioactive compounds. Keywords: T.Chebula, Extraction, Total Phenolic compound (TPC), Total flavonoid compound (TFC), Total antioxidant activity (TAA), α,α-diphenyl-β-picrylhydrazyl (DPPH) scavenging activity (DSA), Response surface methodology (RSM), GC-MS