Effects of ultrasonic treatment on the maturation of Zhenjiang vinegar

High-quality vinegars are traditionally produced by aging them in barrels or bottles. However, these processes are very time-consuming. To accelerate of Zhenjiang vinegar maturation, the ultrasound was used to treat the steeped vinegar. Results showed that, the optimum ultrasonic power, time and ethanol addition for aging vinegar were determined to be 50 W/100 mL, 75 min and 0.75% (V/V), respectively. Under the optimum experimental conditions, the total amino acid of fresh vinegar decreased from 1082.259 mg/100 mL to 871.045 mg/100 mL. Several volatile components increased significantly, such as the total esters, aldehydes and heterocyclic. Total non-volatile organic acids increased from 202.59 mg/10 mL to 233.87 mg/10 mL. The changes of above-mentioned components develop towards the direction of mature vinegar. Coupling the HS-SPME/GC-MS analysis data with Principal Components Analysis, ultrasonic treatment vinegar was determined to be equivalent to 2-3 years of natural aged Zhenjiang vinegar. This study has showed that ultrasound is promising not only in shortening the aging time and lowering costs for the vinegar-making industry, but also in producing fine vinegar.