Symphony of kinetics and statistical design approaches for response analysis during tray drying of Lagenaria siceraria leaves

Drying characteristics of horticultural produce often target studies on the process parameters so as to derive useful data for the development of value-added products with better shelf life and nutritional characteristics. Often the associated symphony of the diverse approaches is not being addressed. Considering Lagenaria siceraria leaves and intermittent airflow-assisted tray dryer as the model vegetable and drying process, respectively, this article focusses towards the efficacy of both approaches so as to obtain useful insights. In these approaches, while moisture content, vitamin C and antioxidant activity were considered as response variables, drying time and temperature were chosen as the process parameters that shall be optimized. The kinetic analysis involved a trial-and-error-based optimality of process variables along with the evaluation of moisture diffusivity and fitness of empirical models. The response surface methodology (RSM)-based statistical design of experiments enabled analysis of variance, identification of best fit model and optimization of process variables. During kinetic analysis, while Page model was best fit to represent drying characteristics in the range of 40-70 degrees C, logarithmic model was best fit model for a drying temperature of 80 degrees C. The moisture diffusivity varied from 1.79 to 5.36 x 10(-12) m(2) s(-1) along with an activation energy of 25.93 kJ mol(-1). Among both approaches, RSM provided quicker identification of optimal process parametric values (61.62 degrees C drying temperature and 292 min drying time) for an optimal combination of response variables (3.28% moisture, 113.36 mg (100 g)(-1) vitamin C and 89.37% antioxidant activity). The dried leafy vegetable can be analysed to possess higher combinations of antioxidant activity and vitamin C content along with other proximate parameters to thereby indicate its potential as a useful ingredient to prepare value-added products such as soups and other ready to cook/eat products.

Automated summary

This research focused on the drying characteristics of Lagenaria siceraria leaves using different approaches, optimizing process variables through trial-and-error methods to achieve optimal drying results.