Impact of different thin layer drying temperatures on the drying time and quality of butterfly pea flowers

Abstract

With attractive flower colours ranging from dark green to purple, Butterfly pea (Clitoria ternatea L.) is grown year-round in Vietnam. The purpose of this study is to determine the effect of air temperature on drying time and antioxidant compounds of Butterfly pea flowers, fitting the drying curves and testing the goodness of fit. In this study, air drying characteristics of the Butterfly pea flowers were determined using drying air temperature from 55oC to 70oC at a constant air velocity of 1 m/s. The data of experimental moisture loss were fitted to selected seven thin-layer drying models. The effect of drying conditions on the anthocyanin and total phenolic compound changes of Butterfly pea flower were compared. The effect of temperature on the diffusivity was described using the Arrhenius equation with an activation energy of 71.63 kJ.mol- ¹. At increasing temperature, the effective moisture diffusivity values ranged from 2.39×10-12 and 7.76×10-12 m²s - ¹. The mathematical models were compared according to the three statistical parameters such as the coefficient of determination (R2 ), reduced chi-square (χ 2 ) and root mean square error (RMSE) between the observed and predicted moisture ratios. The highest value of R2 (99.8%) and the lowest values of χ 2 (0.0004) and RMSE (0.0178) were observed for drying air temperature of 70oC. Among the seven mathematical models tested with experimental data, the Page model could sufficiently be described the drying characteristics of the Butterfly pea flower.

Effect of Foaming Conditions on Foam Properties and Drying Behavior of Powder from Magenta (Peristropheroxburghiana) Leaves Extracts

“…Further more, higher thermal energy promotes the movement of water molecules in the food resulting in a reduction in drying time with increasing drying temperature [38]. Thes results are quite similar to previous studies reported on different plant food such a blanched pumpkin slices [39], butterfly pea flowers [10], and mango slices [40].…”

“…Drying of the stable foam structure will make an important contribution to the improvement of moisture transmission, as the surface area increases due to air incorporation with foaming [4]. The low temperature and short drying time of foam mat drying were chosen to maintain the available nutrients present in the extract [10,31].…”

“…The Page model may be assumed as the best-fitted model to exhibit the good drying behavior for most of the peach samples. Doymaz [41] indicated that the Page model fit the experimental drying data of persimmon slices better than other empirical models at 50, 60, and 70 • C. The drying process of butterfly pea flowers was well-described by the Page model, according to Thuy, Minh, Ha, and Tai [10]. The Page model was discovered to be suitable for drying red chiles [42].…”

“…The estimated Deff values for the Vernonia amygdalina leaves [43]with the effective diffusivities ranged from 4.55x10 −12 to 5.48x10 −12 m 2 /s at 40 to 60°C. The estimated Deff values of dried butterfly pea flowers varied in the range of 2.392 × 10 −12 to 7.756 × 10 −12 m 2 /s at 55 to 70°C [10]. The values of ln(Deff) vs. 1/T (1/K) are plotted to determine the influence of temperature on effective diffusivity.…”

“…In addition, the drying method and drying temperature also have an important influence. Many experimental studies and mathematical models on the drying qualities of various plants, such as papaya [7], carrot [8], tomato [9], and butterfly pea flowers [10], have been conducted.…”