RESUMO
Engineering conservation during the drying process is paramount as it will help in the preservation and cost minimization of food products during processing to avoid spoilage and maximize their utilization in society. Unlike other yam species, three-leaved yam starch (TLYS) contains phytonutrients for the treatment of ailments such as diabetes and rheumatism. This work examined the energy and exergy of TLYS drying. The starch was extracted from the tuber and dried while the temperature, time, air velocity, and sample thickness were varied. TLYS proximate and SEM analysis revealed a significant amount of starch. Energy analysis revealed that energy utilization (EU) and energy utilization ratio (EUR) increased as the temperature rose and decreased as drying time increased; energy efficiency (EE) increased steadily and then reduced as drying time increased. Exergy analysis revealed that drying temperature increased exergetic efficiency and loss; drying time increased exergetic efficiency from 30 min to 4 h. The highest exergy loss was observed when the sample was dried for 4 h and the thickness is 17 mm; as the thickness decreased to 12.75 mm, the exergy loss decreased from 2.471392 J/s to 1.459247 J/s; the highest exergy efficiency of 2.471392 J/s was observed at the thickness of 4.25 mm, and the sustainability index increased as the sample thickness increased and decreased as the drying air temperature decreased. Response surface methodology (RSM) was utilized to model and optimize the effect of the process's inherent operating factors (temperature, time, and air velocity) and maximize the process's energy and exergy efficiency. The (Analysis of Variance) ANOVA revealed a second-order polynomial model with an R2 (0.9911), Adj R2 (0.9797) and Pred R2 (0.8577) for energy efficiency and R2 (0.9824), Adj R2 (0.9598), and Pred R2 (0.7184) for exergy efficiency, indicating a significant correlation between observed and predicted values. At a temperature of 60 °C, a time of 3 h, and an air velocity of 1.5 m/s, the optimal energy efficiency of 75.09 % and exergy efficiency of 99.221% were obtained with desirability of 0.997. The findings of this study can be used to improve the design and development of driers for TLYS preservation.
RESUMO
This work investigated the influence of process variables of extraction temperature (35-55 °C), solid to liquid ratio (1:20-1:50 g/mL) and time (100-200 min) on the total phenolic content (TPC) and yield (EY) of Carica papaya leaves (CPL) extracts using Box-Behnken experimental design available in Design Expert software. Bi-objective process optimization was also carried out using the desirability function algorithm. The optimum process variables were later used to design an integrated process for the production of CPL extracts with the assistance of SuperPro Designer software. Scale-up studies and economic analysis for CPL extracts production were investigated in the range of 0.638-20.431 × 103 kg CPL extracts/y to determine the most economically feasible production capacity based on the minimum unit production cost (UPC) of CPL extracts. The risk and sensitivity analyses of the most economically feasible production scale were carried out using the Monte Carlo simulation in Oracle Crystal Ball software. Process variables had notable influences on the TPC and EY of CPL extracts. The extraction temperature of 35 °C, solid to liquid ratio of 40.25 g/mL and time of 100 min gave the optimum TPC of 74.65 mg GAE/g d.b and EY of 18.76 % (w/w). HPLC results indicated that CPL extracts were rich in gallic, betulinic, chlorogenic, ellagic, ferulic and caffeic acids. The designed integrated process showed similar behavior with the laboratory scale of 0.18758 g CPL extracts/batch. The preliminary techno-economic analysis indicated that plant capacity has a strong dependence on the material & energy demands and process economics. Plant capacity of 19.857 × 103 kg CPL extracts/y possessed the least UPC and was selected as the most economically feasible scale. The certainty of obtaining base case UPC value of 525.21 US$/kg CPL extracts was 75.20%. Sensitivity analysis showed that extracts recovery, CPL/water, centrifuge purchase cost, extraction time, extractor purchase cost and extraction temperature contributed -5.3 %, +42.8%, +4.0%, +47.1%, +0.1%, and +0.5%, respectively to the variance in UPC of CPL extracts.