Optimizing extraction methods: the role of solvent polarity in enhancing phenolic content and antioxidant activity in biowaste

Effective management of global biowaste is imperative because conventional methods like landfilling aggravate environmental challenges. In developing countries like Pakistan, such practices are the cause of economic and social problems. The current study investigated the antioxidant properties of extracts obtained from 6 stale vegetables using Soxhlet and maceration techniques after pre-processing of samples, using different polarity solvents. Significant variations in extraction yields and phytochemical composition were observed among different solvents and plant materials. Both Soxhlet and maceration extracts exhibited diverse phytochemical profiles and antioxidant activities, as determined by total phenolic content with Coriandrum sativum 20.177 (via Soxhlet extraction) and Brassica oleracea var. capitata 72.788 (via Maceration), and DPPH assays showed maximum percentage inhibition of Brassica oleracea var. capitata 99.2 (via Soxhlet extraction) and 98.9 (via Maceration). Generally, extracts with ethyl acetate showed maximum extraction of phenolics and antioxidant activity. Statistical analysis revealed a significant positive correlation between total phenolics and antioxidant potential for maceration extracts at the 0.01 level which is < 0.05. Fourier transform infrared (FTIR) spectroscopy identified numerous functional groups responsible for the detected antioxidant potential. These findings highlight the potential of seasonal vegetables as a rich source of polyphenols, with implications for fighting reactive oxidative stress and their valorization that offers sustainable solutions, aiding both environmental conservation and economic viability.