Study on drying methods and their influences on effective components of loquat flower tea

- Relatively higher water-soluble components contents were found at full-bloom stage and in its petal tissue.
- Four water-soluble components contents in flower tea prepared by freeze drying were the highest.
- Microwave drying is a very fast drying method, and protect the effective components better.
- TPC and TFC in hot-air dried samples increased firstly then decreased with temperature.

Different drying methods and their influences on effective components contents of loquat flower tea were investigated in this study. The determination of total polyphenols (TP), total flavonoids (TF), free amino acid (AA), caffeine and triterpene acids showed relatively higher contents were found at full-bloom stage and in petal tissue. This stage flower was dried to produce loquat flower tea by methods of freeze drying, microwave drying, vacuum drying and hot-air drying, respectively. The results showed that four water-soluble components contents in tea prepared by freeze drying were the highest. Those by microwave drying increased firstly, then decreased with power, with the maximum at 420 W. In vacuum-dried tea, total polyphenols content (TPC) and total flavonoids content (TFC) reduced with temperature, but for AA, it increased with temperature. In hot-air dried flower tea, TPC and TFC exhibited a similar tendency as those by microwave dry, with the maximum at 80 °C and minimum at 40 °C. For AA, it increased with temperature. The contents of caffeine, triterpene acid in tea prepared by all drying methods showed no significant difference. It was concluded that the methods of freeze drying and microwave drying at 420 W can protect the effective components preferably.