Isolation and Screening of Bacterial Strains Capable of Degrading the Bitter Substance Naringin and Their Application in Whole Navel Orange Wine

In this study, microbial strains that could effectively degrade naringin from perennial orange orchards in Langshan area of Shaoyang were isolated and screened to address the issue of bitter taste in whole citrus wines. The characteristics of the strains were identified through morphological observations and molecular biology method, and the optimal enzyme production conditions were explored. Based on the optimal enzyme production conditions of the strain, a crude enzyme solution was added to whole citrus wines. The optimal debittering process was determined using single factor and orthogonal experiments combined with electronic tongue detection. Fungal strain F-5, with a naringin degradation rate of 60.42%, was identified as a Pichia sp. The optimal temperature, inoculation amount, and fermentation time for naringinase production by strain F-5 were 28 ℃, 2×108 CFU/mL, and 36 h, respectively. Under these conditions, the naringin degradation rate of strain F-5 by the fermentation medium was increased to 70.02%. The optimal debittering technology of strain F-5 crude enzyme solution applied to whole citrus wines was at the enzymatic hydrolysis temperature was 45 ℃, the addition of crude enzyme concentration was 4.8 g/L, and the enzymatic hydrolysis time was 40 min, during which the bitterness reduction rate was 68.85%. These results provide experimental ideas and methods for screening naringin-degraded microorganisms, which is important for improving the bitter taste of citrus wine and promoting the development of the citrus wine industry.