Neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS), increase as the population ages around the world. Environmental factors also play an important role in most cases. Alcohol consumption exists extensively and it acts as one of the environmental factors that promotes these neurodegenerative diseases. The brain is a major target for the actions of alcohol, and heavy alcohol consumption has long been associated with brain damage. Chronic alcohol intake leads to elevated glutamate-induced excitotoxicity, oxidative stress and permanent neuronal damage associated with malnutrition. The relationship and contributing mechanisms of alcohol with these three diseases are different. Epidemiological studies have reported a reduction in the prevalence of Alzheimer’s disease in individuals who drink low amounts of alcohol; low or moderate concentrations of ethanol protect against β-amyloid (Aβ) toxicity in hippocampal neurons; and excessive amounts of ethanol increase accumulation of Aβ and Tau phosphorylation. Alcohol has been suggested to be either protective of, or not associated with, PD. However, experimental animal studies indicate that chronic heavy alcohol consumption may have dopamine neurotoxic effects through the induction of Cytochrome P450 2E1 (CYP2E1) and an increase in the amount of α-Synuclein (αSYN) relevant to PD. The findings on the association between alcohol consumption and ALS are inconsistent; a recent population-based study suggests that alcohol drinking seems to not influence the risk of developing ALS. Additional research is needed to clarify the potential etiological involvement of alcohol intake in causing or resulting in major neurodegenerative diseases, which will eventually lead to potential therapeutics against these alcoholic neurodegenerative diseases.

Predominant odorants in modern and traditional types of Chinese xiaoqu liquor (Baijiu) were identified and compared by the combined use of gas chromatography−olfactometry, odor activity values (OAVs), and multivariate analyses. A total of 79 aroma compounds were identified in a typical modern type xiaoqu Baijiu (M) and a typical traditional type xiaoqu Baijiu (T), 42 of them had OAV > 1 in both M and T samples. The main differences between the two samples were obtained for the concentration of 23 aroma-active compounds. A total of 22 samples made by different brewing processes were analyzed to confirm the differences. Partial least squares discriminant analysis confirmed that 20 compounds could be used as potential markers for discrimination between modern type xiaoqu Baijiu and traditional type xiaoqu Baijiu. Their difference in content is between 1.5 and 17.9 times for modern type xiaoqu Baijiu and traditional type xiaoqu Baijiu. The results showed the aroma characteristics of modern and traditional type xiaoqu Baijiu clearly and comprehensively, which will provide guidance for modern Baijiu quality control and evaluation.

Baijiu, also referred to as "Chinese liquor", is a traditional spirit that originated in China over 2000 years ago and is the world’s bestselling liquor today. It is produced using a solid-state fermentation process, often using sorghum as raw material, in which a complex microbial cocktail (called "Jiuqu") is introduced to initiate the fermentation process. During fermentation, a plethora of flavor-active metabolites is produced by microbes. Depending on the flavors formed, Baijiu can be subdivided into sauce-aroma-type, strong-aroma-type, and light-aroma-type. A key feature of light-aroma-type Xiaoqu Baijiu (LATXB) is its relatively low concentration of higher alcohols (HA). However, reaching sufficiently low HA concentrations without affecting the overall taste and flavor of LATXB is often difficult. In this project, breeding was used to develop a new Saccharomyces cerevisiae hybrid strain for LATXB production, which shows reduced HA production. This strain, dubbed “hybrid 5”, reduced total HA by 10.3%, without compromising the production of other metabolites or fermentation efficiency when evaluated at an industrial scale (2 tons). Together, these results show the potential of breeding to produce superior, non-GM yeasts that are directly applicable for commercial Baijiu production.

This study aimed to explore the microbial contribution to flavor compound production by analysing the succession patterns and metabolic functional characteristics of microbial communities during Jiuqu preparation, saccharification, and fermentation processes of rice-flavor Baijiu (RFB). The physicochemical parameters during RFB fermentation were systematically monitored, and the volatile flavor profile was characterized using headspace solid-phase microextraction gas chromatography‒mass spectrometry (HS-SPME–GC–MS). Concurrently, metagenomic sequencing was employed to elucidate the microbial community structure and its temporal dynamics throughout the fermentation process. The results of the physicochemical parameters revealed that the reducing sugar content peaked at the end of saccharification and subsequently decreased throughout fermentation, whereas the total acid and total ester contents progressively increased, reaching maximum levels at the fermentation endpoint and maintaining stability. HS-SPME–GC–MS analysis revealed 84 volatile flavor compounds including phenylethanol, ethanol, dimethyl ether, isopentyl alcohol, and acetic acid. Notably, compounds such as L-ethyl lactate, diethyl succinate, and isobutanol were initially synthesized during saccharification and subsequently accumulated during fermentation, emerging as major flavor constituents. Ascomycota and Mucoromycota dominated the fungal community (average relative abundance >1%), whereas Firmicutes and Proteobacteria prevailed among the bacterial phyla. Six genera, Lichtheimia, Kluyveromyces, Lacticaseibacillus, Lactobacillus, Limosilactobacillus, and Schleiferilactobacillus were identified as primary contributors to flavor production during fermentation. Functional analysis revealed that microbial metabolism in fermented mash primarily involved amino acid and carbohydrate metabolism, with glycoside hydrolases (GHs) and glycosyl transferases (GTs) serving as key carbohydrate-active enzymes. This study could improve the comprehensive understanding of the brewing mechanism of RFB and provide a theoretical basis for the development and utilization of microbial resources in the fermented grains and the improvement of RFB quality.