Study on Drying Characteristics, and Quality of <i>Parthenium hysterophorus</i> L. Aerial Biomass Using Tray and Dehumidified Air Drying

Parthenium hysterophorus (congress grass) thrives in biotic and abiotic stress conditions and produces potent secondary metabolites. The optimal vegetative stage aerial parts of the plant were selected to study drying kinetics, develop drying models for shade, tray, and dehumidified air drying, and analyze the proximate composition of both fresh and dried powders. Drying was performed in an open-shade dryer and at a controlled temperature of 40 ± 1°C, using 12 kg of sample per batch, with a tray, a dehumidified dryer. Drying experiment data showed that dehumidified air drying reduced drying time by approximately 23.8% to 57.1% compared to tray and shade drying methods. The moisture ratio versus drying time data was fitted to drying models using MATLAB software, which revealed that the Page model provided an excellent fit for describing mass transport behaviour during the dehumidified air-drying process at 40 ± 1°C with 15% RH. This model demonstrated its effectiveness in predicting drying kinetics, achieving the highest coefficient of determination (R²) of 0.9983 and the lowest standard error of estimate (SEE) of 0.002967, with drying constant (k = 0.3393) and drying exponent (n=1.2970) showing high sensitivity to temperature and RH changes. The results showed that drying significantly enhanced nutrient density. Fresh samples with 624.60% moisture (d.b.), 2.48% crude protein, and 7.86% carbohydrates were transformed through dehumidified drying, reducing moisture to 5.59% and increasing crude protein to 20.92%, crude fiber to 10.75%, and ash content to 6.08%. This powder aids in the efficient extraction of bioactive compounds from heat-sensitive volatile substances, with possible pharmaceutical uses in the treatment of chronic illnesses like cancer.