Characterization of aroma compounds of Chinese famous liquors by gas chromatography-mass spectrometry and flash GC electronic-nose

Hydrophobic carbon quantum dots with red fluorescence: An optical dual-mode and smartphone imaging sensor for identifying Chinese Baijiu quality

Chinese Baijiu (Liquor) is a popular alcoholic beverage, and the ethanol content in Baijiu is closely related to its quality; therefore, it is of great significance to explore a facile, sensitive, and rapid method to detect ethanol content in Baijiu. Hydrophobic carbon quantum dots (H-CQDs) with bright red fluorescence (24.14 %) were fabricated by hydrothermal method using o-phenylenediamine, p-aminobenzoic acid, manganese chloride, and hydrochloric acid as reaction precursors. After the introduction of ultrapure water into the ethanol solution dissolved with H-CQDs, the aggregated H-CQDs resulted in significant changes in fluorescence intensity and absorbance. On this basis, a sensor for detecting ethanol by optical dual-mode and smartphone imaging was constructed. More importantly, the sensor can be used for detecting ethanol content in Chinese Baijiu with satisfactory results. This sensing platform has great potential for quality identification in Chinese Baijiu, broadening the application scope of CQDs in food safety detection.

Characterization and discrimination of the taste and aroma of Tibetan Qingke baijiu using electronic tongue, electronic nose and gas chromatography-mass spectrometry

Consumers rely on flavor characteristics to distinguish different types of Qingke Baijiu (QKBJ). Clarifying QKBJ's traits enhances its recognition and long-term growth. Thus, this study analyzed eight QKBJ samples from different regions of Tibet (Lhasa, Sannan, Shigatse, and Qamdo) using GC-MS, electronic nose and electronic tongue. The radar charts of the electronic tongue and electronic nose revealed highly similar profiles for all eight samples. Fifteen common compounds were found in all samples, with the main alcohol compounds being 3-Methyl-1-butanol, 1-hexanol, isobutanol, 1-butanol, 1-nonanol, and phenylethyl alcohol, imparting fruity, floral, and herbal aromas. However, the Sannan samples had higher total alcohol content than total ester content, emphasizing bitterness. Lhasa1 exhibited the most prominent sweetness, Lhasa2 the most noticeable sourness, and Qamdo the most pronounced umami. Lhasa3 and Lhasa4 had total acid content second only to total ester content. Tyd had the highest alkanes, while Lhasa had most aldehydes among samples.

Application of PLSR in correlating sensory and chemical properties of middle flue-cured tobacco leaves with honey-sweet and burnt flavour

Among the eight types of aroma and flavour characteristics of Chinese flue-cured tobacco (FCT), tobacco grown in Shandong is classified as having a honey-sweet and burnt aroma. To elucidate the key chemical components that determine the characteristics of the honey-sweet and burnt aroma styles of Shandong FCT, we qualitatively and quantitatively evaluated the smoke flavour quality and five categories of flavour-related chemical components (routine components, water-soluble sugars, free amino acids, Amadori compounds and key aroma-active compounds) in Shandong middle FCT leaves using sensory analysis and modern instrumental analysis techniques. The association between the chemical components and sensory quality was analysed. Our results showed that the total sugars, reducing sugars (fructose, glucose, and psicose), total sugar-nicotine ratio, proline-total amino acid ratio, sulphur-containing amino acid-total amino acid ratio and fructosyl-proline (Fru-Pro) were high in premium FCT leaves. The aroma-active compounds associated with the honey-sweet burnt flavour style of the Shandong Middle FCT included sweet-scented 2,3-pentanedione, 2,3-butanedione, butyrolactone, 2-furanmethanol, roasted-like 2-pentylfura, and green-like 1-penten-3-one. Partial least squares regression (PLSR) analysis revealed that 29 aroma precursors were positively correlated with the sensory quality characteristics of Shandong FCT. The results of our study can provide guidance for the targeted improvement and precise regulation of the flavour-style characteristics of Shandong FCT.

Contribution of microorganisms from pit mud to volatile flavor compound synthesis in fermented grains for nongxiangxing baijiu brewing

BACKGROUND

Nongxiangxing baijiu (NB) is known for its distinct flavor profile, which is attributed to key aroma compounds. The exposed fermentation technique, utilizing daqu and solid-state fermentation in pit muds, plays a crucial role in flavor development. Though previous studies have investigated the impact of microorganisms from pit ?ud and fermented grains on flavor compound production, a comprehensive understanding of microbial functions in the entire pit fermentation system is lacking. Herein, we aimed to explore the role of pit-mud-derived microorganisms in shaping the microbial community and flavor compound synthesis in NB.

RESULTS

There are 76 volatile flavor compounds that have been identified in fermented grains during NB fermentation. The main flavor compounds in NB clustered within the same network module, and 27.27% of microorganisms in the core modules of the fermented grain co-occurrence network originated from pit mud. The relationship between pit mud microorganisms and flavor compounds revealed a significant positive correlation (92%). Notably, Prevotella and Sarocladium were identified as the main contributors to this effect on flavor.

CONCLUSION

Microorganisms originating from pit mud influenced the composition and activity of microorganisms in fermented grains and facilitated the production of flavor compounds in NB. © 2023 Society of Chemical Industry.

The improvement of Hovenia acerba-sorghum co-fermentation in terms of microbial diversity, functional ingredients, and volatile flavor components during Baijiu fermentation

The quality of Baijiu was largely affected by raw materials, which determine the flavor and taste. In the present study, organic acids, polyphenols, volatile flavor components and microbial community in Hovenia acerba-sorghum co-fermented Baijiu (JP1) and pure sorghum-fermented Baijiu (JP2) were comprehensively analyzed. Organic acids, polyphenols and volatile flavor components in JP1 were more abundant than JP2. The abundance and diversity of bacteria and fungi in JP1 was higher than that in JP2 in the early stage of fermentation, but presented opposite trend in the middle and late stages. Leuconostoc, Lentilactobacillus and Issatchenkia were dominant genera in JP1. Whereas, Cronobacter, Pediococcus and Saccharomyces occupied the main position in JP2. Lentilactobacillus and Issatchenkia were positively related to most of organic acids and polyphenols. Pseudomonas, Rhodococcus, Cronobacter, Pediococcus, Brucella, Lentilactobacillus, Lactobacillus, Saccharomycopsis, Wickerhamomyces, Aspergillus, Thermomyces and unclassified_f-Dipodascaccae were associated with the main volatile flavor components. The main metabolic pathways in two JPs exhibited the variation trend of first decreasing and then increasing, and the metabolism activity in JP1 were higher than that in JP2. The results demonstrated the introduction of Hovenia acerba improved the functional ingredients and volatile flavor components, which is helpful for the quality promotion of Baijiu. This study identified the key microorganisms and discussed their effect on organic acids, polyphenols and volatile flavor components during the fermentation of Baijiu with different raw materials, providing a scientific basis for the development and production of high-quality Baijiu.

Headspace stir-bar sorptive extraction combined with gas chromatography-mass spectrometry for trace analysis of volatile organic compounds in Schisandra chinensis Baillon (omija)

Analyzing volatile organic compounds (VOCs) in food is crucial but challenging. Schisandra chinensis Baillon (omija) is an herbal plant with various functional health activities. Previous VOC analyses focused on S. chinensis fruit but not its leaves. Therefore, VOCs in S. chinensis fruit and leaves were analyzed using headspace stir-bar sorptive extraction (HS-SBSE)-GC-MS, and optimal conditions were established. Various factors, such as the sample preparation method, twister stir-bar type, sample amount, extraction temperature, and extraction time, expected to affect extraction were carefully optimized. Under the optimal conditions, 35 and 40 VOCs were identified in S. chinensis fruit and leaves, respectively. This HS-SBSE method is capable of rapid analysis and a low contamination rate without requiring organic solvents. These findings provide practical guidelines for HS-SBSE applications in various food matrices by providing analytical methods for VOC detection.

Re-Rolling Treatment in the Fermentation Process Improves the Aroma Quality of Black Tea

Aroma is a vital factor influencing tea quality and value. It is a challenge to produce a kind of black tea with a floral/fruity aroma, good taste, and without a green/grassy odor simultaneously using small- and medium-leaf tea species. In this study, the effect of re-rolling treatment on the aroma quality of small-leaf Congou black tea was investigated using the methods of the equivalent quantification of aroma and gas chromatography-mass spectrometry (GC-MS). Sensory evaluation showed that re-rolling treatment improved the aroma quality of Congou black tea by conferring upon it floral and fruity scents. In total, 179 volatile compounds were identified using GC-MS, of which 97 volatiles showed statistical differences (Tukey s-b(K), p < 0.05). Re-rolling treatment significantly reduced the levels of alcoholic fatty acid-derived volatiles (FADVs) and volatile terpenoid (VTs), but increased the levels of aldehydic and ester FADVs, most amino acid-derived volatiles (AADVs), carotenoid-derived volatiles (CDVs), alkene VTs, and some other important volatile compounds. Based on the odor characteristics and fold changes of differential volatile compounds, hexanoic acid, hexyl formate, cis-3-hexenyl hexanoate, (Z)-3-hexenyl benzoate, hexyl hexanoate, phenylacetaldehyde, benzyl alcohol, β-ionone, α-ionone, dihydroactinidiolide, ipsenone, β-farnesene, β-octalactone, melonal, etc., were considered as the potential key odorants responsible for the floral and fruity scents of re-rolled black tea. In summary, this study provides a novel and simple processing technology to improve the aroma quality of small-leaf Congou black tea, and the results are beneficial to enriching tea aroma chemistry.

Analysis of physicochemical properties of dry-cured beef made from Hanwoo and Holstein meat distributed in South Korea

The purpose of the study is to check the possibility of developing dry-cured meat from Hanwoo (South Korean native cattle) and Holstein cattle considering the differences between breeds and use this data for the preparation and development of dry cured ham unique to South Korea. Same-grade Semitendinosus muscle from Hanwoo and Holstein was cured using a curing agent with 4.6% salt content at 4 °C for 7 days, and then aged for 70 days. Data was analyzed through physicochemical characterization, and the manufacturing period was established through weight loss, volatile basic nitrogen (VBN), thiobarbituric acid reactive substances (TBARS). Moisture content and weight loss of both samples significantly decreased during the manufacturing process (P < 0.05). TBARS was significantly higher in Hanwoo and VBN in Holstein (P < 0.05). According to the values of VBN (less than 20 mg/100 g) and TBARS (less than 2 mg MDA/kg), dry aging for 5 weeks is appropriate for both samples. The principal component analysis of 5 weeks-aged Holstein showed a dramatically changing trend due to myofibril fragmentation as indicated by Sodium dodecyl sulfate-polyacrylamide-gel electrophoresis. In addition, 5 weeks-aged Holstein contains methanethiol (cheese), butan-2-one (butter), and 3-3-ethyl-2-methyl-1,3-hexadiene (fatty acid-derive) compounds that represent fermentation and aging flavors. Therefore, the possibility of product development was confirmed by the 5-week aging of Holstein dry-cured ham.

Alcohol acyltransferases for the biosynthesis of esters

Esters are widely used in food, energy, spices, chemical industry, etc., becoming an indispensable part of life. However, their production heavily relies on the fossil energy industry, which presents significant challenges associated with energy shortages and environmental pollution. Consequently, there is an urgent need to identify alternative green methods for ester production. One promising solution is biosynthesis, which offers sustainable and environmentally friendly processes. In ester biosynthesis, alcohol acyltransferases (AATs) catalyze the condensation of acyl-CoAs and alcohols to form esters, enabling the biosynthesis of nearly 100 different kinds of esters, such as ethyl acetate, hexyl acetate, ethyl crotonate, isoamyl acetate, and butyl butyrate. However, low catalytic efficiency and low selectivity of AATs represent the major bottlenecks for the biosynthesis of certain specific esters, which should be addressed with protein molecular engineering approaches before practical biotechnological applications. This review provides an overview of AAT enzymes, including their sequences, structures, active sites, catalytic mechanisms, and metabolic engineering applications. Furthermore, considering the critical role of AATs in determining the final ester products, the current research progresses of AAT modification using protein molecular engineering are also discussed. This review summarized the major challenges and prospects of AAT enzymes in ester biosynthesis.

Tracing the Volatilomic Fingerprint of the Most Popular Italian Fortified Wines

The aim of the current study was to provide a useful platform to identify characteristic molecular markers related to the authenticity of Italian fortified wines. For this purpose, the volatilomic fingerprint of the most popular Italian fortified wines was established using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME/GC-MS). Several volatile organic compounds (VOCs), belonging with distinct chemical groups, were identified, ten of which are common to all the analyzed fortified Italian wines. Terpenoids were the most abundant chemical group in Campari bitter wines due to limonene's high contribution to the total volatilomic fingerprint, whereas for Marsala wines, alcohols and esters were the most predominant chemical groups. The fortified Italian wines VOCs network demonstrated that the furanic compounds 2-furfural, ethyl furoate, and 5-methyl-2-furfural, constitute potential molecular markers of Marsala wines, while the terpenoids nerol, α-terpeniol, limonene, and menthone isomers, are characteristic of Vermouth wines. In addition, butanediol was detected only in Barolo wines, and β-phellandrene and β-myrcene only in Campari wines. The obtained data reveal an adequate tool to establish the authenticity and genuineness of Italian fortified wines, and at the same time constitute a valuable contribution to identify potential cases of fraud or adulteration to which they are subject, due to the high commercial value associated with these wines. In addition, they contribute to the deepening of scientific knowledge that supports its valorization and guarantee of quality and safety for consumers.

Analyzing the Quality Parameters of Apples by Spectroscopy from Vis/NIR to NIR Region: A Comprehensive Review

Spectroscopic methods deliver a valuable non-destructive analytical tool that provides simultaneous qualitative and quantitative characterization of various samples. Apples belong to the world's most consumed crops and with the current challenges of climate change and human impacts on the environment, maintaining high-quality apple production has become critical. This review comprehensively analyzes the application of spectroscopy in near-infrared (NIR) and visible (Vis) regions, which not only show particular potential in evaluating the quality parameters of apples but also in optimizing their production and supply routines. This includes the assessment of the external and internal characteristics such as color, size, shape, surface defects, soluble solids content (SSC), total titratable acidity (TA), firmness, starch pattern index (SPI), total dry matter concentration (DM), and nutritional value. The review also summarizes various techniques and approaches used in Vis/NIR studies of apples, such as authenticity, origin, identification, adulteration, and quality control. Optical sensors and associated methods offer a wide suite of solutions readily addressing the main needs of the industry in practical routines as well, e.g., efficient sorting and grading of apples based on sweetness and other quality parameters, facilitating quality control throughout the production and supply chain. This review also evaluates ongoing development trends in the application of handheld and portable instruments operating in the Vis/NIR and NIR spectral regions for apple quality control. The use of these technologies can enhance apple crop quality, maintain competitiveness, and meet the demands of consumers, making them a crucial topic in the apple industry. The focal point of this review is placed on the literature published in the last five years, with the exceptions of seminal works that have played a critical role in shaping the field or representative studies that highlight the progress made in specific areas.

Amino Acids Drive the Deterministic Assembly Process of Fungal Community and Affect the Flavor Metabolites in Baijiu Fermentation

Nutrient fluctuation is ubiquitous in fermentation ecosystems. However, the microbial community assembly mechanism and metabolic characteristics in response to nutrient variation are still unclear. Here, we used Baijiu fermentation as a case example to study the responses of microbial community assembly and metabolic characteristics to the variation of amino acids using high-throughput sequencing and metatranscriptomics analyses. We chose two fermentation groups (group A with low amino acid and group B with high amino acid contents). The two groups showed similar succession patterns in the bacterial community, whereas they showed different succession in the fungal community wherein Pichia was dominant in group A and Zygosaccharomyces was dominant in group B. The β-nearest taxon index (βNTI) revealed that bacterial community was randomly formed, whereas fungal community assembly was a deterministic process. Variance partitioning analysis and redundancy analysis revealed that amino acids showed the largest contribution to the fungal community (37.64%, P = 0.005) and were more tightly associated with it in group B. Further study revealed that serine was positively related to Zygosaccharomyces and promoted its growth and ethanol production. Metatranscriptomic analysis revealed that the differential metabolic pathways between the two groups mainly included carbohydrate metabolism and amino acid metabolism, which explained the differences of ethanol production and volatile metabolites (such as isoamylol, isobutanol, and 2-methyl-1-butanol). Then these metabolic pathways were constructed and related gene expression and active microorganisms were listed. Our study provides a systematical understanding of the roles of amino acids in both ecological maintenance and flavor metabolism in fermentation ecosystems. IMPORTANCE In spontaneous fermented foods production, nutrient fluctuation is a critical factor affecting microbial community assembly and metabolic function. Revealing the microbial community assembly mechanism and how it regulates its metabolic characteristics in response to nutrient variation is helpful to the management of the fermentation process. This study provides a systematical understanding of the effect of amino acids on the microbial community assembly and flavor metabolisms using Baijiu fermentation as a case example. The data of this study highlight the importance of the nutrient management in fermentation ecosystems.

Comprehensive identification of key compounds in different quality grades of soy sauce-aroma type baijiu by HS-SPME-GC-MS coupled with electronic nose

In the production of soy sauce-aroma type baijiu (SSAB), the quality of base liquor significantly affects the finished liquor's quality. Moreover, low-quality liquor may cause health problems. The different quality grades of base liquor were analyzed to investigate the relationship between the quality and the key compounds in SSAB. In this study, samples were evaluated by the sensory and further analyzed by headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) coupled with electronic nose (E-nose). First, by sensory evaluation, the sauce, floral and fruity, fermented aromas and taste indicators (softness, fullness, harmony, purity and persistence) were positively correlated with the quality grade of the base liquor. The E-nose could distinguish the different quality grades of base liquor well. Second, differential compounds were identified via untargeted metabolome based on the HS-SPME-GC-MS. 16 common differential compounds were shared in the base liquor from different fermentation rounds, including 11 esters, 1 alcohol, 2 aldehydes and 2 ketones. It was found that the higher the quality grade of the base liquor, the richer the content of aromatics, alcohols, aldehydes and ketones. The principal component analysis (PCA) biplots of the differential compounds in the different quality grades of base liquor indicated that the superior-grade base liquor has a strong fruity aroma. By correlation analysis of the differential compounds and sensors responses of E-nose, furfuryl ethyl ether, butanoic acid ethyl ester, isopentyl hexanoate, nonanoic acid ethyl ester and 3-methyl-1-butanol had a significant effect on the response intensity of E-nose sensors. In the present study, the key differential compounds between the different quality grades of base liquor were identified, and the sensory differences between the base liquor were digitized.

Non-Targeted Chemical Characterization of JUUL-Menthol-Flavored Aerosols Using Liquid and Gas Chromatography

The aerosol constituents generated from JUUL Menthol pods with 3.0% and 5.0% nicotine by weight (Me3 and Me5) are characterized by a non-targeted approach, which was developed to detect aerosol constituents that are not known to be present beforehand or that may be measured with targeted methods. Three replicates from three production batches (n = 9) were aerosolized using two puffing regimens (intense and non-intense). Each of the 18 samples were analyzed by gas chromatography electron ionization mass spectrometry and by liquid chromatography electrospray ionization high-resolving power mass spectrometry. All chemical constituents determined to differ from control were identified and semi-quantified. To have a complete understanding of the aerosol constituents and chemistry, each chemical constituent was categorized into one of five groups: (1) flavorants, (2) harmful and potentially harmful constituents, (3) leachables, (4) reaction products, and (5) chemical constituents that were unable to be identified or rationalized (e.g., chemical constituents that could not be categorized in groups (1–4). Under intense puffing, 74 chemical constituents were identified in Me3 aerosols and 68 under non-intense puffing, with 53 chemical constituents common between both regimens. Eighty-three chemical constituents were identified in Me5 aerosol using an intense puffing regimen and seventy-five with a non-intense puffing regimen, with sixty-two chemical constituents in common. Excluding primary constituents, reaction products accounted for the greatest number of chemical constituents (approximately 60% in all cases, ranging from about 0.05% to 0.1% by mass), and flavorants—excluding menthol—comprised the second largest number of chemical constituents (approximately 25%, ranging consistently around 0.01% by mass). The chemical constituents detected in JUUL aerosols were then compared to known constituents from cigarette smoke to determine the relative chemical complexities and commonalities/differences between the two. This revealed (1) a substantial decrease in the chemical complexity of JUUL aerosols vs. cigarette smoke and (2) that there are between 55 (Me3) and 61 (Me5) unique chemical constituents in JUUL aerosols not reported in cigarette smoke. Understanding the chemical complexity of JUUL aerosols is important because the health effects of combustible cigarette smoke are related to the combined effect of these chemical constituents through multiple mechanisms, not just the effects of any single smoke constituent.

Novel Insight into the Formation of Odour-Active Compounds in Sea Buckthorn Wine and Distilled Liquor Based on GC-MS and E-Nose Analysis

Sea buckthorn wine (SW) and distilled liquor (DL) are fruit wines with beneficial health effects. However, their unpleasant flavour limits their development and widespread acceptance. Therefore, it is necessary to analyse their flavour composition and changes. In this study, differential metabolites of sea buckthorn DL during processing were analysed, and the relationships between E-nose sensor values and key volatile organic compounds (VOCs) were established. The results show that 133 VOCs were identified, with 22 aroma-contributing components. Fermentation significantly increased the content of VOCs, especially esters. A total of seven and 51 VOCs were significantly upregulated after fermentation and distillation, respectively. Meanwhile, seven sensors were positively correlated with the increased level of alcohols and esters, and reflected the increasing trends of 10 key VOCs.

Marker-Independent Food Identification Enabled by Combing Machine Learning Algorithms with Comprehensive GC × GC/TOF-MS

Reliable methods are always greatly desired for the practice of food inspection. Currently, most food inspection techniques are mainly dependent on the identification of special components, which neglect the combination effects of different components and often lead to biased results. By using Chinese liquors as an example, we developed a new food identification method based on the combination of machine learning with GC × GC/TOF-MS. The sample preparation methods SPME and LLE were compared and optimized for producing repeatable and high-quality data. Then, two machine learning algorithms were tried, and the support vector machine (SVM) algorithm was finally chosen for its better performance. It is shown that the method performs well in identifying both the geographical origins and flavor types of Chinese liquors, with high accuracies of 91.86% and 97.67%, respectively. It is also reasonable to propose that combining machine learning with advanced chromatography could be used for other foods with complex components.

“Key Factor” for Baijiu Quality: Research Progress on Acid Substances in Baijiu

Baijiu is the national liquor of China, which has lasted in China for more than 2000 years. Abundant raw materials, multi-strain co-fermentation, and complex processes make the secrets of baijiu flavor and taste still not fully explored. Acid substances not only have a great influence on the flavor and taste of baijiu, but also have certain functions. Therefore, this paper provides a systematic review for the reported acid substances, especially for their contribution to the flavor and functional quality of baijiu. Based on previous studies, this paper puts forward a conjecture, a suggestion, and a point of view, namely: the conjecture of “whether acid substances can be used as ‘key factor’ for baijiu quality “; the suggestion of “the focus of research on acid substances in baijiu should be transferred to evaluating their contribution to the taste of baijiu”; and the view of “acid substances are ‘regulators’ in the fermentation process of baijiu”. It is worth thinking about whether acid substances can be used as the key factors of baijiu to be studied and confirmed by practice in the future. It is hoped that the systematic review of acid substances in baijiu in this paper can contribute to further in-depth and systematic research on baijiu by researchers in the future.

Screening of a Novel Lactiplantibacillus plantarum MMB-05 and Lacticaseibacillus casei Fermented Sandwich Seaweed Scraps: Chemical Composition, In Vitro Antioxidant, and Volatile Compounds Analysis by GC-IMS

Lactic acid fermentation is a promising method for developing sandwich seaweed scraps. The objectives of this study were to investigate the effect of fermentation with Lactiplantibacillus plantarum MMB-05, Lactiplantibacillus casei FJAT-7928, mixed bacteria (1:1, v/v) and control on the physicochemical indexes, in vitro antioxidant activity, and volatile compounds of Porphyra yezoensis sauce. Sensory evaluation was also performed. The results indicated that all lactic acid bacteria strains grew well in P. yezoensis sauce after 72 h of fermentation, with the viable cell counts of L. plantarum MMB-05 exceeding 10.0 log CFU/mL, the total phenolic content increasing by 16.54%, and the lactic acid content increasing from 0 to 44.38 ± 0.11 mg/mL. Moreover, the metabolism of these strains significantly increased the content of umami, sweet and sour free amino acids in P. yezoensis sauce. The total antioxidant capacity of L. plantarum MMB-05, L. casei FJAT-7928, mix and control groups increased by 594.59%, 386.49%, 410.27%, and 287.62%, respectively. Gas chromatography-ion mobility spectrometry (GC-IMS) analysis suggested that aldehydes and ketones accounted for the largest proportion, and the relative contents of acids and alcohols in P. yezoensis sauce increased significantly after lactic acid bacteria fermentation. In addition, the analysis of dynamic principal component analysis (PCA) and fingerprinting showed that the volatile components of the four treatment methods could be significantly distinguished. Overall, the L. plantarum MMB-05 could be recommended as an appropriate starter for fermentation of sandwich seaweed scraps, which provides a fundamental knowledge for the utilization of sandwiched seaweed scraps.

The Effect of Berry Pomace on Quality Changes of Beef Patties during Refrigerated Storage

This study aims to evaluate the ability of raspberry and blackberry pomace to inhibit lipid oxidation and prolong the refrigerated storage of beef patties. Berry pomace was incorporated into beef patties at the concentration of 1, 3, and 5%. Packed patties were stored for 9 days at 4 °C temperature and the quality of the meat was evaluated on the 0, 3rd, 6th, and 9th day. The natural mass loss during storage, the pH as well as the lipid oxidation were evaluated by thiobarbituric acid-reactive substance (TBARS) method. GC was used to determine the amount of fatty acids and e-nose, based on ultrafast gas chromatography, was used for the determination of volatile organic compounds in beef patties before and after the storage. The highest mass loss during refrigerated storage was observed in the control beef patties, while the berry pomace absorbed water and reduced the loss. The pomace additive influenced the decrease in the patties pH during the storage. Berry pomace can be very effective in relation to lipid oxidation, and as little as 1% of berry pomace influenced the decrease in the TBAR’s values in the patties stored for nine days by 3.06 and 2.42 times, depending on the pomace compared to the control patties. The use of berry pomace in meat products can reduce lipid oxidation, increase their fiber content and act as a thickener, as well as contribute to the usage of agri-food by-products.

Relationships between Shanghai Five Different Home-Brewed Wines Sensory Properties and Their Volatile Composition Assessed by GC-MS

In order to determine the key aroma components of home-brewed wines made from different local grapes in Shanghai. In the work, the identification and quantification of 63 aroma compounds of five home-brewed wines characterized by gas chromatography-mass spectrometry (GC-MS) combined with Headspace Solid-Phase Microextraction (HS-SPME). To study the possible correlation between the sensory attributions and 22 aroma compounds in Odor Activity Value (OAV) > 1 for five home-brewed wines, the Partial Least Squares Regression (PLSR) was a multivariate data analysis performed. Furthermore, to investigate the percentage of contribution of a particular aroma compound to its overall flavor, the relative odor contribution (ROC) and odor activity value of volatiles in home-brewed wines were conducted and performed. According to the comprehensive results, Summer Black Seedless grape (SBSG) and Black Beet grape (BBG) were the most appropriate varieties to be brewed wines for people in Shanghai or around it.

Comparative Analysis of the Floral Fragrance Compounds of Panax notoginseng Flowers under the Panax notoginseng-pinus Agroforestry System Using SPME-GC-MS

Panax notoginseng is a medicinal plant in China, the flowers of which have high medicinal value. To study the differences in the floral fragrance compounds of P. notoginseng flowers (bionic wild cultivation) from the forests of Yunnan Province, the floral fragrance compounds from four varieties of P. notoginseng flowers (four-forked seven leaves, three-forked seven leaves, four-forked five–seven leaves, and three-forked five–six leaves) were compared and analyzed via headspace solid phase microextraction combined with gas chromatography–mass spectrometry methods. A total of 53 floral fragrance compounds from the P. notoginseng flowers were divided into eight categories, mainly consisting of terpenes, alkynes, aromatic hydrocarbons, and alcohols. Moreover, high contents of 3-carene, germacrene D, (−)-α-gurjunene, valencene, (+)-γ-gurjunene, menogene, and aromandendrene were identified from the flowers of different P. notoginseng varieties. Interestingly, floral fragrance compounds such as 3-carene, valencene, aromandendrene, menogene, and (+)-γ-gurjunene were first reported in the flowers of P. notoginseng. Cluster analysis showed that P. notoginseng with four-forked and three-forked leaves clustered into two subgroups, respectively. In addition, principal component analysis showed that (+)-γ-gurjunene, (+)-calarene, copaene, 1,8,12-bisabolatriene, γ-elemene, (–)-aristolene, caryophyllene, 3-carenes, and 2,6-dimethyl-1,3,6-heptatriene can be used to distinguish the floral fragrance components of four P. notoginseng flower species. This study provides a theoretical basis for elucidating the floral fragrance compounds emitted from the flowers of different P. notoginseng varieties in an agroforestry system.

Characterization and Discrimination of Apples by Flash GC E-Nose: Geographical Regions and Botanical Origins Studies in China

Forty-one apple samples from 7 geographical regions and 3 botanical origins in China were investigated. A total of 29 volatile compounds have been identified by flash GC E-nose. They are 17 esters, 5 alcohols, 3 aldehydes, 1 ketone, and 3 others. A principal component analysis was employed to study the relationship between varieties and volatiles. A partial least squares discriminant analysis (PLS-DA), stepwise linear discriminant analysis (SLDA), and decision tree (DT) are used to discriminate apples from 4 geographical regions (34 apple samples) and 3 botanical origins (36 apple samples). The most influential markers identified by PLS-DA are 2-hexadecanone, methyl decanoate, tetradecanal, 1,8-cineole, hexyl 2-butenoate, (Z)-2-octenal, methyl 2-methylbutanoate, ethyl butyrate, dimethyl trisulfide, methyl formate, ethanol, S(-)2-methyl-1-butanol, ethyl acetate, pentyl acetate, butyl butanoate, butyl acetate, and ethyl octanoate. From the present work, SLDA reveals the best discrimination results in geographical regions and botanical origins, which are 88.2% and 88.9%, respectively. Although machine learning DT is attempted to classify apple samples, the results are not satisfactory.

Characterization of Korean Distilled Liquor, Soju, Using Chemical, HS-SPME-GC-MS, and Sensory Descriptive Analysis

The volatile compounds and sensory profiles of 18 different types of distilled soju, chosen with regard to various raw materials and distillation methods (atmospheric vs. vacuum), were explored using headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS) and descriptive analysis. General chemical properties such as pH, total acidity (TA), total soluble solids (°Brix), and lactic acid concentration were also determined. A total of 56 volatile compounds, comprising 31 esters, 11 alcohols, 1 acid, 4 aldehydes, 3 ketones, and 6 miscellaneous compounds, were identified. From the principal component analysis (PCA) of the volatile data, samples made using atmospheric distillation such as MSO and PJU showed a clear difference from decompressed distillation samples. Based on the PCA of the sensory data, there was also a clear distinction between samples by their distillation method. To explore relationships among chemical, volatile, and sensory data sets, multiple factor analysis (MFA) was applied. Yeasty and earthy flavors showed a close relationship with 1-nonanol, octatonic acid, and longer-chain esters such as ethyl phenylacetate and ethyl tetradecanoate, and with chemical parameters such as TA, °Brix, and lactic acid.

Insights into the Aroma Profile of Sauce-Flavor Baijiu by GC-IMS Combined with Multivariate Statistical Analysis

Aroma is among the principal quality indicators for evaluating Baijiu. The aroma profiles of sauce-flavor Baijiu produced by 10 different manufacturers were determined by GC-IMS. The results showed that GC-IMS could effectively separate the volatile compounds in Baijiu, and a total of 80 consensus volatile compounds were rapidly detected from all samples, among which 29 volatile compounds were identified, including 5 alcohols, 14 esters, 2 acids, 2 ketones, 5 aldehydes, and 1 furan. According to the differences in aroma profile found by multivariate statistical analysis, these sauce-flavor Baijiu produced by 10 different manufacturers can be further divided into three types. The relative odor activity value of the identified volatile compounds indicated that seven volatile compounds contributed most to the aroma of sauce-flavor Baijiu in order of aroma contribution rate, and they were ethyl hexanoate, ethyl pentanoate, ethyl 2-methylbutanoate, ethyl octanoate (also known as octanoic acid ethyl ester), ethyl 3-methylbutanoate, ethyl butanoate, and ethyl isobutyrate. Correspondingly, the main aromas of these sauce-flavor Baijiu produced by 10 different manufacturers were sweet, fruity, alcoholic, etheral, cognac, rummy, and winey. On the one hand, this study proved that GC-IMS is well adapted to the detection of characteristic volatile aroma compounds and trace compounds in Baijiu, which is of positive significance for improving the aroma fingerprint and database of sauce-flavor Baijiu. On the other hand, it also enriched our knowledge of Baijiu and provided references for the evaluation and regulation of the flavor quality of sauce-flavor Baijiu.

Carbonyl flavor compound-targeted colorimetric sensor array based on silver nitrate and o-phenylenediamine derivatives for the discrimination of Chinese Baijiu

Baijiu is a distilled liquor of great importance in the food industry. Various aroma types, brands, and grades of Baijiu have filled the market; thus, discrimination for quality control is required. Herein, we constructed a novel colorimetric sensor array based on the redox reaction between silver nitrate and o-phenylenediamine or its derivatives for the discrimination of carbonyl flavor compounds (CFCs) and Baijius. The specific colored products were changed by CFCs depending on the influence of silver nanoparticle aggregation and chemical reactions. The array was used to qualitatively and quantitatively identify 21 CFCs with fast response (<14 min), wide linear range (0.025-25 mmol/L), and low detection limits (<60 μmol/L, 29 nmol/L for carboxylic acids). Finally, the array was successfully applied to the discrimination of 56 Baijius. The method proposed in this study is simple, fast, reliable, and has good application potential for the visual determination of Chinese Baijiu.

Metagenomics-based insights into the microbial community profiling and flavor development potentiality of baijiu Daqu and huangjiu wheat Qu

Daqu and wheat Qu are saccharification and fermenting agents in Chinese huangjiu and baijiu production. This study aimed to investigate the difference between Daqu and wheat Qu in physicochemical indices, microbial communities, functional genes, and the metabolic network of key microbes responsible for flavor synthesis by whole-metagenome sequencing and metabolite analysis. Herein, physicochemical indices indicated that compared with wheat Qu, Daqu exhibited higher protease and cellulase activity and acidity, and lower glucoamylase and amylase enzyme activity. Metagenomic sequencing reveals that although Daqu and wheat Qu community composition have significant differences at species level, they have similar functional genes. Daqu were enriched in Pediococcus pentosaceus, Weissella paramesenteroides, Rasamsonia emersonii and Byssochlamys spectabilis (22.48% of the total abundance), while wheat Qu harbored greater abundances of Saccharopolyspora (54.78%, Saccharopolyspora rectivirgula, Saccharopolyspora shandongensis, Saccharopolyspora hirsuta, Saccharopolyspora spinose, and Saccharopolyspora erythraea). From a functional perspective, the important functions of Daqu and wheat Qu are both amino acid metabolism and carbohydrate metabolism. Meanwhile, a combined analysis among microbiota, functional genes, and dominant flavors indicated S. shandongensis, S. rectivirgula, and S. spinose might be the main contributor to the synthesis of flavor compounds in wheat Qu, while R. emersonii, W. paramesenteroides, Leuconostoc citreum, Leuconostoc mesenteroides, Weissella cibaria and P. pentosaceus may make the greatest contribution to flavor compounds synthesis in Daqu. This study reveals the microbial and functional dissimilarities of Daqu and wheat Qu, and helps elucidating different metabolic roles of microbes during flavor formation.

Exploring Relationships between Aroma, Tasty Components Properties, and Marketing Price of Chinese Cabernet Sauvignon Using Gas Chromatography Mass Spectrum and High-Performance Liquid Chromatography

The purpose of this paper was to find the relationship between aroma and tasty component properties and marketing price of Chinese Cabernet Sauvignon red wines. One-way ANOVA was used to compare differences ( $p<0.05$ ) between concentrations of phenolic compounds, organic acids, monosaccharides and total acidity, total polyphenols, total sugars, and total reducing sugars in various Chinese Cabernet Sauvignon red wines with different marketing prices. Principal component analysis revealed that the presence of higher amount of alcohol appears to be the characteristic feature for the wine samples, which have a lower marketing price, and the higher level of esters and acids were the features of the wine samples with a higher marketing price. Moreover, samples in marketing price area 39 to 79 RMB and samples in marketing price area 188 to 258 RMB can be totally clustered into their own marketing price area by volatile compounds with OAV > 1. Acetic acid, succinic acid, and glucose made a great contribution to most of the wine samples in the marketing price area ranging from 39 to 79 RMB, and glycerol, fructose, and malic acid were the features of most wine samples in the marketing price area ranging from 188 to 258 RMB. Concentrations of total acidity, total polyphenols, total sugars, total reducing sugars, and alcohol content seemed to have no significant distinguishing ( $p<0.05$ ) ability on different samples belonging to different marketing price areas.

The sensory and flavor characteristics of Shaoxing Huangjiu (Chinese rice wine) were significantly influenced by micro-oxygen and electric field

In order to improve the high cost of equipment and difficult management caused by the natural aging of Chinese rice wine (Huangjiu), micro-oxygen (MO) and electric field (PEF) technology are used to accelerate the aging of Huangjiu. The results showed that micro-oxygen and electric field have a significant effect on the sensory characteristics and flavor characteristics of Huangjiu. Compared with the naturally aged Huangjiu, the flavor compounds of Huangjiu treated with micro-oxygen and electric field increase significantly. Based on principal component analysis, Huangjiu processed at 0.35 mg L/day or 0.5 mg L/day combined electric field exhibited similar flavor to the natural aged Huangjiu, which was highly associated with long-chain fatty acid ethyl esters (C13-C18). Moreover, partial least squares regression demonstrated that sensory attributes of cereal aroma and astringency were highlighted after aging time, while fruit aroma, continuation, and full body were dominant after micro-oxygen and electric field treatment. Micro-oxygen and electric field effectively enhanced the quality of Huangjiu, which could be applied in other alcoholic beverages.

Non-Targeted Chemical Characterization of JUUL Virginia Tobacco Flavored Aerosols Using Liquid and Gas Chromatography

The chemical constituents of JUUL Virginia Tobacco pods with 3.0% and 5.0% nicotine by weight (VT3 and VT5) were characterized by non-targeted analyses, an approach to detect chemicals that are not otherwise measured with dedicated methods or that are not known beforehand. Aerosols were generated using intense and non-intense puffing regimens and analyzed by gas chromatography electron ionization mass spectrometry and liquid chromatography electrospray ionization high resolving power mass spectrometry. All compounds above 0.7 µg/g for GC–MS analysis or above 0.5 µg/g for LC–HRMS analysis and differing from blank measurements were identified and semi-quantified. All identifications were evaluated and categorized into five groups: flavorants, harmful and potentially harmful constituents, extractables and/or leachables, reaction products, and compounds that could not be identified/rationalized. For VT3, 79 compounds were identified using an intense puffing regimen and 69 using a non-intense puffing regimen. There were 60 compounds common between both regimens. For VT5, 85 compounds were identified with an intense puffing regimen and 73 with a non-intense puffing regimen; 67 compounds were in common. For all nicotine concentrations, formulations and puffing regimens, reaction products accounted for the greatest number of compounds (ranging from 70% to 75%; 0.08% to 0.1% by mass), and flavorants comprised the second largest number of compounds (ranging from for 15% to 16%; 0.1 to 0.2% by mass). A global comparison of the compounds detected in JUUL aerosol to those catalogued in cigarette smoke indicated an approximate 50-fold decrease in chemical complexity. Both VT3 and VT5 aerosols contained 59 unique compounds not identified in cigarette smoke.

Chemical Characterization of Recycled Consumer Products Using Suspect Screening Analysis

Recycled materials are found in many consumer products as part of a circular economy; however, the chemical content of recycled products is generally uncharacterized. A suspect screening analysis using two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) was applied to 210 products (154 recycled, 56 virgin) across seven categories. Chemicals in products were tentatively identified using a standard spectral library or confirmed using chemical standards. A total of 918 probable chemical structures identified (112 of which were confirmed) in recycled materials versus 587 (110 confirmed) in virgin materials. Identified chemicals were characterized in terms of their functional use and structural class. Recycled paper products and construction materials contained greater numbers of chemicals than virgin products; 733 identified chemicals had greater occurrence in recycled compared to virgin materials. Products made from recycled materials contained greater numbers of fragrances, flame retardants, solvents, biocides, and dyes. The results were clustered to identify groups of chemicals potentially associated with unique chemical sources, and identified chemicals were prioritized for further study using high-throughput hazard and exposure information. While occurrence is not necessarily indicative of risk, these results can be used to inform the expansion of existing models or identify exposure pathways currently neglected in exposure assessments.

Dynamic changes of volatile compounds and bacterial diversity during fourth to seventh rounds of Chinese soy sauce aroma liquor

Chinese soy sauce aroma liquor (CSSL) is a famous Baijiu. Multiple rounds of fermentation, the characteristic of CSSL processing, contributes to the differences in the quality of the liquor of different rounds. In this study, the grains on cooled, stacked, and fermented stages of 4th to 7th rounds were taken, of which the environmental factors, bacterial diversity, and volatile compounds were comprehensively analyzed. Lactobacillaceae, Bacillaceae, Thermoactinomycetaceae, and Enterobacteriaceae were the top four families, of which Lactobacillaceae dominated the fermented stage of each round. Principal component analysis (PCA) and principal coordinate analysis (PCoA) supported the popular view that the liquors of 3rd to 5th rounds possess the best quality. Lactobacillaceae is an extremely critical bacterium for CSSL fermentation. This study provides comprehensive understanding regarding the dynamic changes in fermented grains during the 4th to 7th rounds, which could help to improve the processing technology of CSSL.

Liquor Flavour Is Associated With the Physicochemical Property and Microbial Diversity of Fermented Grains in Waxy and Non-waxy Sorghum (Sorghum bicolor) During Fermentation

The fermentation process of Chinese Xifeng liquor involves numerous microbes. However, the sources of microbes in fermented grain and the link between liquor flavour and physicochemical properties and microbial diversity during fermentation still remain unknown. Herein, two waxy (JiNiang 2 [JN-2] and JinNuo 3 [JN-3]) and four non-waxy (JiZa 127 [JZ-127], JinZa 34 [JZ-34], LiaoZa 19 [LZ-19], and JiaXian [JX]) sorghum varieties were selected for the comprehensive analysis of the relationship between liquor flavour and the physicochemical properties and microbial diversity of fermented grains. Results showed that ethyl acetate was the main flavour component of JZ-127, JZ-34, and JX, whereas ethyl lactate was mainly detected in JN-2, JN-3, and LZ-19. Ethyl lactate accounted for half of the ethyl acetate content, and JX exhibited a higher liquor yield than the other sorghum varieties. The fermented grains of waxy sorghum presented higher temperature and reducing sugar contents but lower moisture and starch contents than their non-waxy counterparts during fermentation. We selected JN-3 and JX sorghum varieties to further investigate the microbial changes in the fermented grains. The bacterial diversity gradually reduced, whereas the fungal diversity showed nearly no change in either JN-3 or JX. Lactobacillus was the most abundant bacterial genus, and its level rapidly increased during fermentation. The abundance of Lactobacillus accounted for the total proportion of bacteria in JX, and it was higher than that in JN-3. Saccharomyces was the most abundant fungal genus in JX, but its abundance accounted for a small proportion of fungi in JN-3. Four esters and five alcohols were significantly positively related to Proteobacteria, Bacteroidetes, and Actinobacteria; Alphaproteobacteria, Actinobacteria, and Bacteroidia; Bacillales, Bacteroidales, and Rhodospirillales; and Acetobacter, Pediococcus, and Prevotella_7. This positive relation is in contrast with that observed for Firmicutes, Bacilli, Lactobacillales, and Lactobacillus. Meanwhile, Aspergillus was the only fungal microorganism that showed a significantly negative relation with such compounds (except for butanol and isopentanol). These findings will help in understanding the fermentation mechanism and flavour formation of fermented Xifeng liquor.

The Potential of Flos sophorae immaturus as a Pigment-Stabilizer to Improve the Monascus Pigments Preservation, Flavor Profiles, and Sensory Characteristic of Hong Qu Huangjiu

Hong Qu Huangjiu (HQW) is distinguished by its inclusion of Monascus pigments, meaning that photosensitivity strongly affects the sensory quality of the wine. In this study, the effects of Flos sophorae immaturus (FSI) on the stability of Monascus pigments, the flavor profiles, and the sensory characteristics of HQW were investigated. After sterilization, the addition of FSI increased the preservation rate of Monascus pigments in HQW by up to 93.20%, which could be accounted for by the synergy of rutin and quercetin in FSI. The total content of the volatile flavor compounds in HQW increased significantly as the added amounts of FSI were increased, especially 3-methyl-1-butanol, 2-methyl-1-propanol, and short-chain fatty acid ethyl esters (SCFAEE). Sensory evaluation and partial least-squares regression revealed that the concentration of FSI significantly affected the aroma characteristics of HQW but had little effect on the mouthfeel. The addition of 0.9 mg/mL FSI yielded a satisfactory HQW with high scores in terms of mouthfeel and aroma. The strong correlation between fruit-aroma, full-body, and SCFAEE suggests that FSI might alter the aroma of HQW by enhancing the synthesis of SCFAEE. Summarily, treatment with FSI represents a new strategy for improving the stability of photosensitive pigments and thus adjusting the aroma of HQW or similar beverages.

Differences between retort distillation and double distillation in cherry spirits with double-kettle equipment

The effects of retort distillation (RD) and double distillation (DD) for producing cherry spirits using unique double-kettle equipment were compared, for the first time. RD improved distillation efficiency and kept methanol at a safe level. Compared with DD, the contents of higher alcohols increased with RD: isobutanol, propanol, and benzyl alcohol increased by 15.5, 32.9, and 37.9%, respectively, with the content of ethyl esters being reduced. In contrast, isoamyl formate, with its cherry aroma, was not detected in DD spirits, but was present at up to 10.71 mgL−1 in RD spirits. Six terpenoids were detected in RD spirits, but only four in DD spirits. These changes were also reflected in the sensory scores. Although the purity and elegance of the RD spirits decreased, their complication, richness, and honey aroma increased. These changes are very important for guaranteeing spirits quality, providing a reference for research and production of cherry distilled spirits.

Quantitative analysis of volatile compounds of four Chinese traditional liquors by SPME-GC-MS and determination of total phenolic contents and antioxidant activities

The aim of this work was to investigate the volatile compositions of four Chinese functional liquors. For this purpose, volatile compounds of four liquors were extracted with head-space solid-phase microextraction (HS-SPME) and analyzed with gas chromatography-mass spectrometry (GC-MS) along with the determination of odor activity value (OAV) and relative odor contribution (ROC). Sixty volatiles were tentatively identified and categorized into the following seven groups: alcohols, esters, fatty acids, carbonyl compound, hydrocarbons, phenols, and other components. The differences in chemical composition of volatile compounds were visualized with heat maps. Odorants were compared with different samples using a statistical analysis of Venn diagrams and a multivariate principal component analysis, and ethyl hexanoate, ethyl acetate, and ethyl octanoate were found to be the key odorants. Besides, abundant phenolic contents and high antioxidant ability of four Chinese functional liquors could potentially bring better health-boosting effects.

Production of an innovative mixed Qu (fermentation starter) for waxy maize brewing and comparison of the quality of different waxy maize wines

BACKGROUND

Waxy maize (Zea mays L. sinensis Kulesh) is a good material for brewing. Waxy maize wine, a kind of Chinese rice wine, is strongly affected by a fermentation starter named Qu. In this study, an innovative mixed Qu, consisting of two yeasts and three molds, was produced and the raw-starch brewing method was applied in winemaking. Three other waxy maize wines fermented by three kinds of commercial Qu were also analyzed for comparison.

RESULTS

Due to superb growth and fermentation characteristics, Saccharomyces cerevisiae CICC1009 and Pichia anomala CICC1851 were chosen to produce yeast Qu. The addition amount of yeast Qu was determined to be 30 g kg^-1 . In terms of chemical properties, mixed Qu was more suitable for making maize wine by the raw-starch brewing method than the three kinds of commercial Qu with which it was compared. The most influential components for the overall aroma profile in maize wines fermented by mixed Qu and Mifeng Qu were ethyl butyrate and β-damascenone, respectively, while in maize wines fermented by Angel Qu and Like Qu the most influential component was ethyl octanoate. Obvious differences were found among four maize wines regarding bitterness, umami, richness, saltiness, and sourness by the electronic tongue. The olfactory characteristics of maize wine fermented by Mifeng Qu were quite different from the other three according to the electronic nose.

CONCLUSION

The innovative mixed Qu can be considered as an excellent starter for raw-starch brewing of waxy maize. The chemical indices and volatile flavor compounds of waxy maize wines were greatly affected by different kinds of Qu. © 2020 Society of Chemical Industry.

Quality properties of whole milk powder on chicken breast emulsion-type sausage

The aim of the study was to determine the effect of whole milk powder (WMP) as heterologous proteins on chicken breast emulsion-type sausages. The quality properties of WMP on such chicken breast emulsion-type sausages were investigated by measuring the proximate composition, pH, color, cooking yield, protein solubility, and by applying other methods, such as texture profile analysis (TPA), microphotograph, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and electronic nose. The crude fat, protein, and ash contents of 15% WMP samples were significantly higher than the control samples (p < 0.05). The redness of the cooked samples significantly increased with an increase in the WMP contents (p < 0.05). The cooking yield of WMP treated samples was significantly higher than the control sample (p < 0.05). Additionally, the hardness, gumminess, and chewiness of WMP treated samples were significantly higher than the control sample (p < 0.05). The sarcoplasmic and myofibrillar proteins of samples containing 15% WMP were significantly higher than the control samples (p < 0.05). The result of SDS-PAGE showed that the C protein, sarcoplasmic protein, actin, and tropomyosin increased with an increase in the WMP contents. The principal component analysis plot of WMP-treated samples was clearly different from that of the control samples. Based on these results, it was predicted that WMP could be useful as heterologous protein on emulsion-type sausage.

Research on the application of liquid-liquid extraction-gas chromatography-mass spectrometry (LLE-GC-MS) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) in distinguishing the Baiyunbian aged liquors

The purpose of the study was to reveal the differences of the flavor compounds among five Baiyunbian aged liquors by liquid-liquid extraction-gas chromatography-mass spectrometry (LLE-GC-MS) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). In optimizing the LLE parameters, an extractant, methyl tert-butyl ether, was found which has a good extract effect and has never been used for the extraction of liquor flavor substances. Then the optimized LLE method has been applied to comprehensively analyze flavor compounds in 3-year-storage liquors (3Y), 5Y, 12Y, 15Y, and 20Y of Baiyunbian liquors combined with GC-MS. The results showed that the number and concentration of total flavor compounds also enhanced with the increase of cellaring ages. The total concentration of flavor compounds in 20Y was the highest (4543.23 mg/L), and the 3Y was the lowest (3984.96 mg/L). Among them, the significant differences among five samples were esters, alcohols, acids and nitrogen-containing compounds. Cluster analysis was used to analyze the aromas profiles by LLE-GC-MS, which revealed relationship among five samples. The results showed that the similarity of the samples was highest between 15Y and 20Y, followed by 3Y and 5Y. The characteristic flavors fingerprints of five kinds of Baiyunbian aged liquors were established by HS-GC-IMS. The results showed that the characteristic peaks in GC-IMS 3D spectra corresponding to flavor compounds can effectively characterize the sample information areas. The sectional intensities of 60 characteristic peaks in the corresponding three-dimensional spectra were selected as variables. After the principal components analysis (PCA) was used to reduce information dimensionality, it was further distinguished by HS-GC-IMS that 3Y and 5Y can be completely separated, but 15Y and 20Y were very similar and cannot be completely distinguished. The obtained results are valuable for the in-depth understanding and further study of flavors of Baiyunbian liquors.

A colorimetric sensor array for the discrimination of Chinese liquors

Although some colorimetric sensor arrays have been developed for the identification of Chinese liquors, they usually require the confirmation of volatile markers in the liquors by chromatography and mass spectrometry firstly. Herein, we present a simple colorimetric sensor array to identify various Chinese liquors in the liquid phase without the aid of other analytical techniques. The colorimetric sensor array consists of six commercially available and inexpensive solvatochromic dyes, and the sensing mechanism of this array is based on the response of solvatochromic dyes to their local polarity. On the basis of the colour changes of the sensor array, different Chinese liquors are discerned readily using pattern recognition methods, and the statistical analysis results (i.e., hierarchical clustering analysis and principal component analysis) reveal that the as-fabricated sensor array can distinguish the subtle differences between different liquors from the same winery and the same flavor type. Moreover, the developed sensor array can even distinguish diverse diluted liquors from the pristine ones.

A novel acid-sensitive quantum dot sensor array for the identification of Chinese baijiu

The organic acid content plays important roles in the flavor and taste of Chinese baijiu. Developing a detection and discrimination technique for organic acids and employing it as a basis in baijiu classification has great practical significance. We employed 3 kinds of acid-sensitive quantum dots (QDs) to construct a fluorescence sensor array for the detection and identification of organic acids in baijiu. We report the first directional use of array sensing detection technology for the evaluation of organic acids in baijiu. Linear discriminant analysis (LDA) was successfully employed to evaluate the ability of the as-developed sensor array to classify organic acids. The Euclidean distance analysis was introduced to prove the provided sensor array possesses good quantitative detection. On this basis, our sensor array was successfully applied to distinguish 16 kinds of baijiu samples. The results were supported by principal component analysis (PCA), LDA, and systematic cluster analysis (HCA). Furthermore, Pearson correlation results indicated a strong correlation between the detection results and the organic acids in baijiu. This simple and accurate method shows potential for quality control and detection in baijiu factories and markets.

A system-level investigation into the pharmacological mechanisms of flavor compounds in liquor

Maotai-flavor liquor, one of the world's most famous natural fermentation food products plays a significant role in traditional Chinese culture and people's daily lives for a long time due to its good taste. However, the pharmacological activities of flavor compounds in Maotai liquor have not been fully elucidated. In answering this question, a system-level analysis was developed by combining in silico ADME evaluation, multi-target prediction, GO enrichment analysis, network pharmacology technology, pathway analysis, as well as experimental verification to elucidate the pharmacological effects of flavor compounds in Maotai liquor. Finally, 55 active compounds and 80 targets were identified to interpret the pharmacological effect of the flavor compounds. Moreover, the key active compounds were verified by in vitro experiments to validate the reliability of our approaches. Our study provides a novel integrated strategy to comprehensively understand the pharmacological activities of complex components in Maotai liquor. PRACTICAL APPLICATIONS: We proposed an integrative strategy by systems pharmacology to investigate the potential active compounds and their related targets, as well as to understand the potential pharmacological mechanism of flavor compounds in Maotai liquor. The present work will not only shed light on the mechanism of active compounds in Maotai liquor at the system level, but also provide a novel approach for discovery of the active compounds that may benefit human health.