Influence of Various Drying Methods on the Antioxidant and Essential Oil Content of Salvia fruticosa Plant

Abstract

Salvia fruticosa (Anatolian sage) contains significant amounts of secondary metabolites, which are essential for the plant's anti-inflammatory, antimicrobial, and antioxidant effects. The drying methods applied post-harvest directly impact the plant's essential oil content, antioxidant activity (ABTS, DPPH), total phenol, and flavonoid levels. In particular, drying temperature and method are critical factors in determining the degradation rate of these compounds, playing an important role in preserving the plant's medicinal and aromatic value. This study aims to investigate the effects of different post-harvest drying methods on the bioactive properties of the Salvia fruticosa to identify the most effective drying method. In this study, Salvia fruticosa plant subjected to various drying methods: sun drying, shade drying, and oven drying at 100°C, 70°C, and 40°C. According to results, drying in shade yielded the highest values of DPPH radical scavenging activity (61.71 mg TEAC/g DW) and ABTS activity (91.39 mg TEAC/g DW), alongside essential oil content (1.60%) and phenolic content (31.41 mg GAE/g DW). In contrast, D100 (drying at 100 oC) showed the lowest values for DPPH, ABTS, essential oil, phenol, and flavonoid as 19.16 mg TEAC/g DW, 43.95 mg TEAC/g DW, 0.06%, 13.02 mg GAE/g DW, and 35.29 mg rutin/g DW, respectively, highlighting the detrimental effects of thermal degradation. These findings suggest that lower temperature drying methods, specifically shade and sun drying, are more effective in preserving the integrity of beneficial compounds, thus maximizing the antioxidant capacity and essential oil value of sage.