Abstract:Through the analysis of nutrients，functional components，gas chromatography-mass spectrometry（GC-MS）of volatile compounds and the analysis of relative odor activity value（ROAV），the effects of different particle sizes on the quality of coix seed beverage were discussed.The results showed that the content of total flavonoids，polysaccharides，soluble solids and viscosity of the F3 treatment group with aperture size of 0.063 mm were superior，and the suspension stability of the tissue was significantly higher than that of the F1 and F2 groups （P ＜0.05）.The volatile aroma compounds in the coix seed beverage were alkanes，aldehydes，esters，alcohols，aromatic compounds，furans，ketones and acids.There were 6 kinds of key odor compounds（ROAV≥1）in the optimal coix seed beverage of F3 group，which were （E，E）-2，4-decadienal，（E）-2-nonenal，（E）2-decenal，decanal，nonaral，octanal.At the same time，2-undecenal，hexanal，1-octen-3-ol，（E）-2-octenal played an important modification role in the overall flavor （0.1≤ROAV＜1）.Decanal，nonanal，（E，E）-2，4-decadienal，octanal and hexanal were the key odor compounds （ROAV≥1）in the F1 control group of coix seed beverage.Studies had shown that the crushed grain size of coix seed raw materials had an impact on the nutritional indicators，tissue stability and flavor of the beverage products.Studies had shown that the different particle sizes of coix seed had an impact on the nutritional indicators，tissue stability and flavor of beverage products.Moderate crushing degree of coix seed beverage had a more delicate and stable，which could improve the nutrition and flavor quality of the beverage.Coix seed beverage obtained by screening coix seed powder with a aperture size of 0.063 mm have the best quality.