Optimization of plasma-activated water-assisted extraction of basil seed (Ocimum basilicum L.) mucilage: Effect on phenols, flavonoids, antioxidant, thermal and morphological properties

Abstract

This study aimed to enhance basil seed mucilage extraction using plasma-activated water (PAW). The response surface method (RSM) and rotating center composite design (RCCD) were used, considering the activation time of deionized water with cold plasma (0–15 min), water temperature (55–85 °C), and seed-water ratio (1:33–1:65). Optimal conditions for extraction were identified as a temperature of 78.39 °C, an activation time of 15 min, and a seed-water ratio of 1:50, leading to a 2.11 times higher extraction yield (7.6 %) compared to untreated samples (3.6 %) which had the same conditions. PAW-treated samples showed improved biological activities, including higher levels of total phenolic compounds (58.56 mg GAE/100 g), total flavonoids (87.81 mg QE/g), and DPPH inhibitory activity (60.98 %). Additionally, PAW treatment raised the melting point of basil seed mucilage, with minimal change in melting enthalpy. These alterations were attributed to plasma chemical reactions and increased surface energy of polysaccharide granules.