Abstract: The proportion and microstructure of oat bran and endosperm were analyzed on several selected typical cultivars of naked oat (Avena nuda). At the same time, the distribution profiles of β-glucan and phenolic acids in oat bran (pericarp, and seed coat with aleurone layer), and endosperm was tested to establish a method for determining the processing suitability of oats rice and oat flour. Finally, the method was used to verify the suitability of the existing mainstream processing technologies for oat rice and oat flour. The results showed that for all the selected varieties, β-glucan was mainly enriched in the bran containing a value of 85.7 mg/g, which was about 4.5 times higher than that in endosperm. Moreover, the contents of p-coumaric acid and ferulic acid in oat bran were 0.099 and 1.00 mg/g, which were 24 and 48 times higher than those in endosperm, respectively. In addition, the contents of p-coumaric acid and ferulic acid in pericarp were 13 and 2.7 times higher than those in testa + aleurone layer, respectively. The average content of β-glucan in the second bran obtained from oat rice processing was 1.7%, which was far lower than that in oat bran, suggesting that grinding was suitable for oat processing. While the contents of β-glucan in the fourth and fifth brans obtained from oat flour processing were 6.73% and 7.80%, which were close to that in oat bran, suggesting the processing was excessive. In conclusion, by analyzing the contents of β-glucan and phenolic acids in the oat bran obtained by grinding, we can determine the processing degree of oat products, which will provide technical support for oat processing.

Key words: oat rice, oat flour, processing suitability, oat bran, β-glucan, phenolic acids