Effect of high pressure treatment and short term storage on changes in main volatile compounds of Chinese liquor

Chemical characterization and sensory properties of apple brandies aged with different toasted oak chips and ultra-high-pressure treatments

Aging is an important processing step of producing high quality apple brandy. In this study, apple brandies aged by traditional method and using three different toasted oak chips combined with or without ultra-high-pressure (UHP) treatment were prepared to compare their differences in chemical characterization and sensory properties. The results indicated that the brandies aged with toasted oak chip increased the levels of total acidity, volatile acidity and phenolic compounds. It also had the desirable color and taste. The brandy aged with toasted oak chip combined with UHP reached the highest levels of total acidity (1.06 g/L), total phenolic content (284.92 mg/L) and aromatic esters (49.37 %). Therefore, the aging with high toasted oak chip combined with UHP treatment could cut the traditional aging time to meet the same quality as traditional aging method. The results are very useful to develop a fast and efficient aging technique for brandy production.

The Effects of Ultrasonic and Gamma Irradiation on the Flavor of Potato Wines Investigated by Sensory Omics

Aroma is one of the most fascinating and least-known mysteries of Baijiu research. The volatile compounds (VOCs) of potato wine were evaluated by sensory omics techniques in order to comprehend their overall flavor characteristics and investigate the effects of ultrasonic treatment and gamma irradiation therapy on the aroma of the wine. The findings revealed that a total of 14 flavor compounds were identified by GC-MS. Isoamyl alcohol, ethyl octanoate, and 1,1-diethoxyethane were the key aroma components, according to GC-O analysis. A total of 50 volatile substances were identified by GC-IMS. After being subjected to irradiation and ultrasonic treatment, the alcohol level of the potato wine reduced while the esters content increased. By calculating the relative odor activity value, a total of 29 aroma components were classified as key aroma compounds (ROAV > 1). According to the results of the sensory evaluation-fruity, Fen-flavor, and sweet-and the acceptability of the irradiated and ultrasonicated potato wine were improved. Therefore, the use of ultrasonic and irradiation therapy in potato wine, as well as the overall aroma building of potato wine, can be supported theoretically by this study.

Furfural and organic acid targeted carbon dot sensor array for the accurate identification of Chinese baijiu

Baijiu quality control has always been a major challenge for researchers. In this paper, taking furfural which is closely related to baijiu brewing process and organic acids related to baijiu fermentation process and microorganism types as the main discriminating factors, a carbon dot (CDs) sensor array targeting furfural and organic acids was constructed to identify 41 kinds of baijiu. Through the fluorescence response investigation of CDs synthesized by isomers of benzenediol, aminophenol, and phenylenediamine to different baijiu, two CDs synthesized by meta-benzene substitutions containing -NH₂ were selected to build a fluorescence sensor array. Due to the aggregation-induced enhancement effect between furfural and the CDs, and the protonation of organic acid and the CDs, different fluorescence changes were observed, the sensor array combined with partial least squares regression could quantitatively analyze furfural and organic acids. What is more, semi-quantitative analysis of furfural and lactic acid in baijiu was performed. Owing to the interaction of the two CDs with furfural and organic acids in baijiu, the sensor array could accurately identify different baijiu through linear discriminant analysis. This sensor array has potential applications in the quantitative analysis of flavor substances in other alcoholic beverages, moreover, this method could provide a quick response and practical tool for real-time quality control monitoring in the baijiu industry.

Rapid analysis of Baijiu volatile compounds fingerprint for their aroma and regional origin authenticity assessment

Solid-phase microextraction - mass spectrometry (SPME-MS) and fast gas chromatography based electronic nose (GC-E-Nose) were used and compared for their suitability to distinguish Baijiu of various aroma types and geographical origin. Baijiu is a traditional Chinese distilled spirit produced with complex consortia of microorganisms, which results in very complex aroma compounds profiles. A total of 65 Baijiu samples representing 6 aromas were investigated. Strong aroma types from 3 regions were examined for their origin. Data acquired on two analytical systems were processed using uniform statistical approach. Data were pre-processed for multi-classification (OPLS-DA) models as well as for binary classification (PLS-DA) ones. Aroma and regional classification performed using OPLS-DA indicated that the approach based on SPME-MS had better fitness and prediction ability compared with GC-E-Nose. The total correct classification rate for SPME-MS was 94.44% for aroma and 100% for region, whereas for GC-E-Nose these values were 91.53% and 93.94% respectively.

Evolution of the key odorants and aroma profiles in traditional Laowuzeng baijiu during its one-year ageing

Changes of key odorants and aroma profiles of Chinese Laowuzeng baijiu during its one-year ageing were determined by HS-SPME-AEDA and direct injection-AEDA (DI-AEDA). Ethyl hexanoate, (E,E)-2,4-decadienal, and 2-phenylethyl acetate showed the highest FD value (486) in all ageing stages. With regards to aroma profiles, fruity, floral, acidic, sweet/honey and cheesy aromas were enhanced during storage, while pickled vegetable, grain and alcoholic notes weakened during the ageing. Quantitation and OAVs showed that most of the aroma compounds (OAVs > 1), including ethyl esters, aldehydes, and acids, increased their contents within the same period, whereas nonanal, 2-phenylethyl acetate, ethyl benzoate, 4-ethylguaiacol, propanol and 3-methyl-1-butanol decreased in content after the storage of 365 days. Simulated aged samples, in which fresh samples were spiked with 18 compounds, were examined by triangle tests, which indicated that the "fruity" compounds were crucial for maintaining the special aroma profile of an aged sample.