ABSTRACT
Stock markets are vulnerable to systemic events. This study analyzes the impact of multiple macro-characteristic events, such as trade friction, on China's stock markets. By leveraging a new event study and quantile regression method, we find that trade friction events significantly affect the stability of the stock market from six trading days in advance to five trading days after the event. The expected effects of trade friction events significantly influence the high quantile of stock market returns before these events. The low quantile of returns is affected as the news confirmation time approaches. Friction events have an impact before, and on the day of the event, and affect the stability of the stock market by influencing the low-quantile group, whereas mitigation events affect the stability of the stock market for a longer time by influencing the high-quantile group. Regulators and investors should pay attention to the impact of trade friction on the stock market. Regulators should also pay proper attention to the direction of public opinion on positive and negative news to maintain stock market stability.
ABSTRACT
BACKGROUND: Rosy vinegar is a well-known traditional Chinese product whose flavour is affected by its lactic acid content. In this study, Lactobacillus bacteria were employed to increase the content of lactic acid during the ethanol fermentation stage. RESULTS: The optimised fermentation parameters were determined as an inoculation amount of 3% (v/v), a temperature of 30 degrees C and an initial pH value of 4.0. Fermentation under these optimal conditions resulted in an alcohol degree of 6.2% (v/v), a total acidity of 49.5 g L(-1) and a lactic acid content of 4.14 g L(-1). The content of lactic acid (4.14 g L(-1)), which approached the level achieved by solid state fermentation, was 3.56-fold higher than that in vinegar fermented without lactic acid bacteria (1.16 g L(-1)). CONCLUSION: The results indicate that mixed fermentation with Lactobacillus plantarum and Saccharomyces cerevisiae strains greatly increases the lactic acid content and improves the flavour of rosy vinegar.
