Strong-aroma Baijiu is a traditional Chinese spirit distilled from grains that undergo solid-state fermentation. At the end of each fermentation cycle, a significant quantity of Huangshui accumulates at the bottom of the fermentation pit, constituting one of the primary by-products in the brewing process of strong-flavor liquor. In this report, the chemical component analysis of Huangshui obtained from a strong-flavor liquor factory revealed a diverse array of organic acids, alcohols, esters, starch, reducing sugars, amino acids, and other compounds present in Huangshui. Additionally, two specialized solid-state fermentation models were developed to investigate the formation process of Huangshui. Our findings demonstrate a positive correlation between the yield of Huangshui and the initial moisture content of fermented grains. It is concluded that Huangshui is the percolate produced during the solid-state brewing process of strong-flavor liquor, with its water content originating from the initial moisture of fermented grains.

Lactic acid (LA) is a significant byproduct in Baijiu fermentation, with both D(-)-lactic acid (D(-)-LA) and L-lactic acid (L(+)-LA) being present due to the diverse microbial metabolism involved. L(+)-LA, a key industrial raw material, is metabolizable by humans, unlike D(-)-LA. This study aims to isolate microorganisms from fermented grains that preferentially produce L(+)-LA and apply these strains to Baijiu fermentation processes. We analyzed 106 commercially available Baijiu samples, along with fermented grains, yellow water, and Baijiu samples from 10 Baijiu factories, confirming the coexistence of D(-)-LA and L(+)-LA in fermentation products. Notably, a strong correlation was found between L(+)-LA in fermented grains and L-ethyl lactate (L(+)-EL) in Baijiu. Microbial community analysis revealed that Lactobacillus and Bacillus were the dominant bacterial groups, with a succession of microbial communities throughout fermentation. Two strains, A6 and B12, identified as Bacillus licheniformis and Bacillus cereus, respectively, were isolated for their high selectivity in L(+)-LA production. Both strains demonstrated a high yield of L(+)-LA in fermentation tests. Incorporating these strains into both liquid- and solid-state fermentation systems markedly increased the proportion of L(+)-EL relative to total ethyl lactate in Baijiu. This study successfully isolated and applied L(+)-LA-producing strains to fermentation models, offering a practical strategy for increasing L(+)-LA content in Baijiu.

The human brain is highly dependent on oxygen, utilizing approximately 20% of the body’s oxygen at rest. Oxygen deprivation to the brain can lead to loss of consciousness within seconds and death within minutes. Recent studies have identified regions of the brain with spontaneous episodic hypoxia, referred to as "hypoxic pockets." Hypoxia can also result from impaired blood flow due to conditions such as heart disease, blood clots, stroke, or hemorrhage, as well as from reduced oxygen intake or excessive oxygen consumption caused by factors like low ambient oxygen, pulmonary diseases, infections, inflammation, and cancer. Severe hypoxia in the brain can manifest symptoms similar to Parkinson’s disease (PD), including cerebral edema, mood disturbances, and cognitive impairments. Additionally, the development of PD appears to be closely associated with hypoxia and hypoxic pathways. This review seeks to investigate the molecular interactions between hypoxia and PD, emphasizing the pathological role of hypoxic pathways in PD and exploring their potential as therapeutic targets.