Optimization of Mixed Solid-state Fermentation Process of Dehusked Barley with Rhizopus oryzae and Lactobacillus and Its Antioxidant Activity

In order to make the best of the barley resource and improve its utilization ratio in food industry,using dehusked barley as raw material to make barley kernel fermented food by mixed fermentation of Rhizopus oryzae and Lactobacillus. The effects of inoculation quantity,inoculation proportion,fermentation time and fermentation temperature on the total acidity and sweetness were estimated by 3,5-dinitrosalicylic acid method and titration method. The optimized process conditions were determined through single-factor experiments and orthogonal experiments on the basis of sensory evaluation. Meanwhile,the antioxidant activity of fermented and unfermented dehusked barley extraction in vitro was also analysed. The results indicated the optimized process conditions were 8 h of soaking time at room temperature,10 min of boiling time,36 h of fermentation time,0.5% of inoculation dose,10:3 of inoculation proportion,and 32℃ of fermentation temperature. Under these conditions,the sensory evaluation scores were(9.3±0.35)points(full marks was10 points). The antioxidant activity in vitro showed the hydroxyl radical and DPPH radical scavenging capacity had a significant improvement after fermentation for 36 h(p<0.05). The hydroxyl radical and DPPH radical scavenging capacity of fermented dehusked barley(100 mg)extraction were 93.38%±0.88% and 80.18%±1.58% respectively.