Optimization of Cryogenic Grinding Parameters for Ashwagandha Roots

This study aimed to optimize the cryogenic grinding process of Ashwagandha (Withania somnifera) roots, a medicinal herb used in the Indian subcontinent, to preserve quality by minimizing thermal degradation. The effect of moisture content, grinding temperature, and grinder speed on Ashwagandha powder quality was evaluated. Response Surface Methodology (RSM) with a Box–Behnken design guided the experiments. The optimization sought to reduce particle size and colour difference while retaining essential oil and total phenolic content. The results indicated that the optimal conditions for grinding were 6.58% moisture content, -119°C temperature, and 9477 rpm grinder speed, with a desirability of 0.92. The resulting particle size was 0.381 mm, with 43.99 mg 100g^-1 of essential oil, 394.77 mg of total phenols (GAE 100g^-1), and specific energy consumption of 1.596 kWh kg^-1. Statistical analysis validated the optimized conditions. Thus, this study provides valuable information for the production of high-quality Ashwagandha powder for pharmaceutical applications. These optimized conditions provide a foundation for pilotscale trials and technoeconomic assessments aimed at industrial adoption.