In recent years, with the booming international alcohol - consumption trend, criminals have employed various means to commit fraud, such as illegal additives, unauthorized blending, and misleading labeling, posing a threat to consumer rights. For example, a report from 315 revealed that some so-called special supply liquors are actually fake special liquors, with the alcohol content not matching the label and containing illegal flavoring agents, endangering human health. Although experiencedalcoholic beverage connoisseurs can recognize the sensory attributes of alcoholic beverages, this method is often limited by individual subjective differences and lacks objective standards. Conventional techniques such as chromatography and spectroscopy have made some achievements in this field, but they face numerous challenges in simultaneously detecting multiple compounds in the alcoholic beverage, such as the selection of chromatographic columns and optimization of detection conditions, cumbersome pre-treatment steps for target substance extraction, and how to eliminate matrix effects to ensure data accuracy. These issues limit the applications. In contrast, methods rely on colorimetric, fluorescent and electrochemical readouts are more convenient, but they perform poorly in the analysis of complex samples, making it difficult to meet the simultaneous determination needs of diverse components.
Recently, Professor Shuo Huang's group conducted a screening and evaluation of common biological nanopores. They ultimately selected the single phenylboronic acid-modified hetero-octameric Mycobacterium smegmatis porin A nanopore (MspA-90PBA) as a representative. For the first time, they successfully achieved rapid nanopore analysis of different alcoholic beverages without the need for complex pretreatment processes. In a palm-sized device, only a few microliters of liquid are required to detect various components through the nanopore artificial tongue, such as illegal additives and sweetness, and to create a unique barcode identifier for each alcoholic beverage sample (Figure 1), providing strong technical support for the identification of adulteration in market products. Although the current artificial tongue cannot detect methanol contamination in alcoholic beverages, future versions may potentially solve this issue.
Fig 1: Rapid nanopore analysis of alcoholic beverages
A major concern of nanopore analysis of alcoholic beverages is that the ethanol present in the sample may cause denaturation of the protein nanopore or rupture of the lipid bilayer. To investigate this, a nanopore measurement was carried out with an octameric M2MspA. To further determine which type of nanopore is more suitable for alcoholic beverage analysis, a semi-sweet white wine was tentatively applied as a model sample. A variety of biological nanopore types were tested, including WT α-HL, M2MspA, and the single adapter-modified hetero-octameric MspA nanopores—MspA-90PBA, MspA-NTA-Ni, and MspA-NTA-Cu. After comparison, the MspA-90PBA nanopore was able to report plenty of long-residing, highly characteristic, and diverse types of events, ultimately being selected for rapid analysis of alcoholic beverages.
Subsequently, the author utilized this sensor to achieve the rapid detection of DL-LA (DL-lactic acids) in distilled liquors (Figure 2). Six internationally renowned types of distilled liquors, including Chinese baijiu, brandy, whisky, rum, vodka, and gin, were selected as representatives for analysis. The results showed that there were significant differences in the nanopore signatures of different types of distilled liquors, mainly reflected in the content of DL-LA and background events.
Fig 2: Rapid identification of DL-LA in distilled alcoholic beverages
In order to further expand the applications of this technology, machine learning assisted MspA-90PBA was subsequently applied to fermented alcoholic beverages, such as red wine, white wine, and beer (Figure 3), which contain more nutrients. The results indicated that, besides the model analytes, corresponding clustered unknown events (marked with red arrows) were also detected in different fermented alcoholic beverages, and this information togetherconstituted the unique “barcode” of each sample. It is noteworthy that the barcodes of similar fermented alcoholic beverages (e.g., red wine 1 and 2) are completely different, which will provide strong support for the quality control and adulteration identification of alcoholic beverages. Finally, this technology was successfully applied to the sweetness grading of wines and the detection of illegal additives (sucrose and D-tartaric acid), demonstrating its significance in alcoholic beverage production and food safety management.
Fig 3: Nanopore analysis of fermented alcoholic beverages
This related paper entitled “Nanopore signatures of major alcoholic beverages” has been published on Matter on December 17th, 2024 (paper link: https://www.sciencedirect.com/science/article/pii/S2590238524006003). Prof. Shuo Huang from our department is the corresponding author. Ph.D. student Pingping Fan is the first author. This project was funded by the National Natural Science Foundation of China (grant no. 22225405 to S.H.), the National Key R&D Program of China (grant no. 2022YFA1304602 to S.H.), the Fundamental Research Funds for the Central Universities (grant no. 020514380336 to S.H.), the Programs for High-Level Entrepreneurial and Innovative Talents Introduction of Jiangsu Province (individual and group program to S.H.), and the Excellent Research Program of Nanjing University (grant no. ZYJH004 to S.H.).