关键词: 苦荞茶, 香气, 营养, 固相微萃取, 气相色谱-质谱分析

Abstract: The distribution of major chemical components during the production of steamed and roasted whole tartary buckwheat tea samples was tracked to explore the effects of steaming, roasting and reconstructed granulation on the aroma and nutritional components of tartary buckwheat tea. Meanwhile, both tartary buckwheat teas were comparatively analyzed for volatile aroma components by solid-phase microwaveextraction (SPME) coupled with GC-MS. The final products obtained following different procedures showed significant differences in chemical composition (P＜0.05). During the production of steamed tartary buckwheat tea, proteins were mainly distributed in the yellow powder at a level of 27.51%, the reducing sugar content of 0.69% in the raw material decreased to 0.28% in the fine product, and total flavonoids were mainly distributed in the polished powder and yellow powder at levels of 4.98% and 4.63%, respectively. As a result, the total flavonoid content of the final product was as low as 1.38% compared with only 1.20% for roasted tartary buckwheat grains. The total flavonoid content of tea-containing reconstructed granules prepared from buckwheat husk powder, rich in flavonoids (4.56%), was as high as 6.87%. Roasted whole tartary buckwheat tea as a mixture of roasted tartary buckwheat grains and tea-containing reconstructed granules had considerably better quality and flavor than its steamed counterpart. The major aroma compounds of steamed tartary buckwheat tea were alkanes and alkenes, while roasted tartary buckwheat tea contained aldehydes and alkanes as major aroma compounds and was also rich in phenols, alcohols, ethers, ketones and esters, which caused better flavor in roast tartary buckwheat tea and than steamed one.

Key words: tartary buckwheat tea, aroma compounds, solid phase microextraction (SPME), GC-MS