The Changes in Bioactive Compounds and Antioxidant Activity of Chia (Salvia hispanica L.) Herb under Storage and Different Drying Conditions: A Comparison with Other Species of Sage

Studies on herb chia (Salvia hispanica L.) are very limited. Therefore, the aim of this study was to assess how different drying methods and periods of storage affect the bioactive properties of the herb Salvia hispanica and to compare it with other species of sage (Salvia officinalis L. and Salvia sclarea L.). In fresh herbs, directly after drying (freeze-drying, natural drying, and drying at 30, 40, and 50 °C), and after storage (3, 6, and 12 months), the following analyses were performed: content of total carotenoids and total polyphenols, polyphenol profile (including 25 compounds), and antioxidant activity. Additionally, the basic chemical compositions of the herbs were analyzed. To the best of our knowledge, the content of total carotenoids and the quantitative polyphenol profile in Salvia hispanica and Salvia sclarea were evaluated for the first time. The obtained results showed that the barely investigated herb Salvia hispanica is rich in polyphenolic compounds and shows high antioxidant activity. In all the tested species, rosmarinic acid was the most abundant polyphenolic compound. The use of different drying methods allowed us to determine that freeze-drying was the most effective for preserving polyphenols and carotenoids. Long-term storage up to 12 months resulted in a gradual reduction in antioxidant activity and in the content of polyphenols and carotenoids.