Abstract:In this study, comparisons were made on the effects of four different pretreatments, baking, extrusion, ultrafine grinding, and thermostable α-amylase coupled with extrusion, on the content of soluble β-dextran in oats, as well as the effects of four enzymes, cellulase, acidic protease, neutral protease and mesophilic α-amylase on the hydrolysis of oats and resultant contents of soluble β-dextran and free phenols. The optimized hydrolysis process was established according to the Box-benhnken centeral composite design based on the single-factor experiments. The obtained results showed that the four pretreatment processes significantly increased the content of soluble β-dextran, with the treatment using thermostable α-amylase coupled with extrusion leading to the greatest increase. The use of neutral protease significantly increased the content of soluble β-dextran in oats, while both neutral protease and mesophilic α-amylase were able to facilitate significantly (p<0.05) increased free phenol content in oats. The optimum conditions for the complex enzymatic hydrolysis of oat paste were established (pH 6.6, 51 ℃, duration 2 h, solid-liquid ratio, 1: 8). Under which, the contents of soluble β-dextran and free phenol in oat pastewere 3.18 ± 0.28 mg / g DW and 65.71 ± 5.96 mg / 100g DW, respectively. This paper provides useful information for the development of oat beverages enriched with soluble β-dextran and free phenols.
