Effects of different Jiuqu on the quality and antioxidant activity of highland barley Baijiu

To screen suitable Jiuqu for brewing highland barley Baijiu, using commercial highland barley Baijiu as a control, the highland barley Baijiu samples were prepared by 6 different flavor types (strong-flavor, rice-flavor, sesame-flavor, Feng-flavor, sauce-flavor, and light-flavor) of Jiuqu fermentation using highland barley as the raw material. The physicochemical indicators and volatile flavor compounds in highland barley Baijiu were analyzed by headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and high performance liquid chromatography (HPLC) techniques, and the scavenging ability of highland barley Baijiu on 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-diaminodis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS) free radical and Ferric ion reduction/antioxidant capacity (FRAP) were investigated. The results showed that highland barley Baijiu brewed with different flavor types of Jiuqu had their own characteristics. Among them, the highland barley Baijiu with Feng-flavor Jiuqu had the optimal quality indicators and antioxidant capacity, the amino acids, essential amino acids, alcohol content, liquor yield, amino acid nitrogen, and total phenols were 1 130.86 mg/L, 210.22 mg/L, 5.96%vol, 75.80%, 0.27 g/L and 451.90 mg/L, respectively. The sensory score was 83 points, the DPPH and ABTS free radical scavenging abilities were 0.25 mg vitamin C equivalent (VCE)/ml and 0.176 mg VCE/ml, respectively, and the FRAP value was 0.21 mg/ml. The most volatile flavor substances were detected in highland barley Baijiu brewed with Feng-flavor Jiuqu (49 kinds), including 30 characteristic aroma compounds, and the highland barley Baijiu sample had significant mellow, floral, and fruity characteristics. In conclusion, Feng-flavor Jiuqu had potential application value in improving the quality of highland barley Baijiu.