Barley flour addition during acetic acid fermentation: impacts on flavor and nutrients and regulatory strategies.

To develop high-quality cereal vinegar, this study utilized barley flour and wheat bran for acetic acid fermentation. Compared to the wheat bran group (WB group), total phenols, β-glucan, ethyl acetate, ethyl lactate, ethyl palmitate, and (2R,3R)-(-)-2,3-butanediol were identified as the key nutrients and flavor substances in the barley flour group (BF group). To further enhance the nutritional and flavor quality, these key nutrients and flavor substances were selected as indicators. Optimization was achieved by adjusting the barley flour amount to 83%, fermentation temperature to 33 °C, mash turning cycle to 23 h, and seed pei amount to 250 g. Under these conditions, the optimized group achieved 5.64 g/100 mL total acid, 0.62 mg/mL total phenols, 3.71% β-glucan (2.02 times that of the WB group), and 5.87 mg/mL key flavor substances (2.34 times that of the WB group). The satisfaction function value under these conditions was 0.54, close to the theoretical value.