Biofortification with Aspergillus awamori offers a new strategy to improve the quality of Shanxi aged vinegar

Shanxi aged vinegar (SAV) is a traditional Chinese grain vinegar proven to be rich in ferulic acid (FA). However, most of the FA present in SAV is in a bound state, reducing its nutritional value. Aspergillus awamori possessed remarkable abilities in producing ferulic acid esterase, which could effectively break ester bonds within plant cell walls to release FA. In this study, A. awamori biofortification was implemented as a strategy in SAV production to increase FA and improve the quality of SAV. Firstly, the levels of basic physicochemical indicators and organic acids were monitored. Additionally, levels of total polyphenols and total flavonoids were measured. These results indicated that biofortified fermentation did not exhibit any significant difference from traditional fermentation; however, the quality of SAV was improved. HPLC was subsequently performed to quantify the amount of FA, and the results in the leaching vinegar reached 11,307.12 μg/100 g, representing a 39.4% increase compared to traditional fermentation. Finally, we utilized GC-MS to analyze the volatile flavor compounds in the leaching vinegar, revealing that adding A. awamori offered SAV more abundant flavor compounds. The present study suggests that A. awamori biofortification gave SAV better nutritional values, providing a potential approach for producing high-quality vinegar.