Determination Of Nutritional Constituents In Buckwheat And The Development Of Novel Taratry Buckwheat Tea

Buckwheat is widely planted in China,and it is known as a kind of edible and pharmaceutical grain due to its high levels of quality protein,flavonoids and other bioactive compounds.Along with the rising of market requirement,as well as recognition in nutritional value of buckwheat,especially tartary buckwheat,buckwheat industry is developing rapidly.In this study,we analyzed the characteristic of nutrition constituents in buckwheat,and investigated the process and quality of tartary buckwheat tea.Buckwheat samples(n=217)were analyzed using near-infrared reflectance spectroscopy(NIRS),then calibration models were established from NIR spectra and values determined by chemical method by partial least-squares(PLS)algorithm with cross-validation.According to the model parameters we obtained,buckwheat protein(R~2=96.26,RPD=5.17)and starch(R~2=91.67,RPD=3.46)content can be detected by NIRS accurately.Fourteen tartary buckwheat varieties were collected and their nutritional constituents(protein,starch,fat,amino acids,fatty acids,flavonoids)were determined.The content of crude protein is 167.18 mg/g,starch content reach up to 612.59 mg/g,the content of fat is 29.03 mg/g and total flavonoid is about 22.55 mg/g.Tartary buckwheat contains abundant essential amino acid and unsaturated fatty acids,and rutin is the dominated flavonoid.Nutritional quality of commercial whole groat and whole plant tartary buckwheat tea collected in China were analyzed.The whole groat tea contained higher contents of starch and rutin,while the whole plant tea contained higher contents of protein,total flavonoid and quercetin.In tea soup,whole plant tea has significantly low dissolution rate of flavonoids.The GC-MS composition analysis indicated that aroma compounds between two kinds of tea were different.Tartary buckwheat was selected as raw materials to preparation of novel tea,the processing method of buckwheat tea was studied and the extract technology of rutin from tartary buckwheat plant were optimized.Results showed that the optimal extraction condition of rutin was alcohol concentration 70%,material-liquid ratio l:30,extraction temperature 60°C and extraction time 20 min.The optimal processing condition was soaking under material-water ratio l:1 and duration 6 h,steaming for 15min,and roasting at 180°C and 20 min.Under these conditions,tartary buckwheat tea is in high quality with natural nutrition and special sweet smell.