Volatile Flavor Substances Research Articles

Influences of Lactiplantibacillus plantarum dy-1 Fermentation on the Bitterness of Bitter Melon Juice, the Composition of Saponin Compounds, and Their Bioactivities.

Lactic acid bacteria fermentation is a beneficial bioprocessing method that can improve the flavor, transform nutrients, and maintain the biological activity of foods. The aim of this study is to investigate the effects of Lactiplantibacillus plantarum dy-1 fermentation on the nutritional components, flavor and taste properties, and composition of saponin compounds and their hypolipidemic and antioxidant activities. The results suggested that the total polyphenol content increased, and the soluble polysaccharides and total saponin contents decreased in fermented bitter melon juice (FJ) compared with those in non-fermented bitter melon juice (NFJ). The determination of volatile flavor substances by GC-MS revealed that the response values of acetic acid, n-octanol, sedumol, etc., augmented significantly, and taste analysis with an electronic tongue demonstrated lower bitterness and higher acidity in FJ. Furthermore, UPLC-Q-TOF-MS/MS testing showed a significant decrease in bitter compounds, including momordicines I and II, and a significant increase in the active saponin momordicine U in the fermented bitter melon saponin group (FJBMS). The in vitro assays indicated that FJBMS exhibited similar antioxidant activities as the non-fermented bitter melon saponin group (NFBMS). The in vitro results show that both NFBMS and FJBMS, when used at 50 μg/mL, could significantly reduce fat accumulation and the malondialdehyde (MDA) content and increased the catalase (CAT) activity, while there was no significant difference in the bioactivities of NFBMS and FJBMS. In conclusion, Lactiplantibacillus plantarum dy-1 fermentation is an effective means to lower the bitterness value of bitter melon and preserve the well-known bioactivities of its raw materials, which can improve the edibility of bitter melon.

Changes in the Volatile Flavor Substances, the Non-Volatile Components, and the Antioxidant Activity of Poria cocos during Different Drying Processes.

Poria cocos (Schw.) wolf (P. cocos) is an important medicinal material with both therapeutic and edible properties. This study investigated volatile constituents, amino acids, proteins, polysaccharides, triterpenoid ingredients, and alcohol-soluble extracts on P. cocos during eight drying processes. A total of 47 volatile components were found and identified; the main volatile components of shade drying (SD) and hot-air drying at 50 °C (HD50) were esters and alcohols, while for drying in hot air at 60 °C~100 °C (△ = 10 °C) and infrared drying (ID), the main compounds were aldehydes and hydrocarbons. The amino acids in P. cocos remained the same when dried with various methods. Compared with SD samples, with the temperature increase, the content of amino acids showed a trend of first decreasing and then increasing, while the content trend of proteins was the opposite. The HD70 samples had the highest content of polysaccharide, triterpenoid ingredients, alcohol-soluble extracts, and antioxidant activity. Furthermore, volatile compounds showed a correlation between non-volatile constituents. This research provides evidence that the aroma, active components, and activity of P. cocos were affected by the drying method.

Improvement of brown yogurt quality by Lactiplantibacillus plantarum S58 and oat β-glucan: Physicochemical properties, sensory quality, and metabolic changes

The flavor quality of brown yogurt is affected by the different fermentation methods. In this study, we investigated the effects of probiotics (Lactiplantibacillus plantarum S58), prebiotics (oat β-glucan), and synbiotics (Lactiplantibacillus plantarum S58 combined with oat β-glucan) on physicochemical properties, consumer acceptance, flavor substances, and metabolites of brown yogurt. The results showed that the addition of probiotics and synbiotics significantly shortened the curdling time of brown yogurt (30 min and 40 min, respectively), and synbiotics improved the physicochemical properties and flavor components of the yogurt. Compared with the control group, the volatile flavor substances in the synbiotic yogurt, such as acetophenone, 2-decanone, and octanoic acid, were significantly increased. Sensory analysis of 111 consumers showed that the sample of synbiotic brown yogurt was highly accepted and close to the ideal point. Synbiotic fermentation alters the metabolic profile of yogurt, increasing the levels of beneficial metabolites and reducing harmful metabolites. In conclusion, synbiotic brown yogurt achieved the highest quality. This study provides a theoretical basis and data support for the development of brown yogurt with high probiotic activity and a unique flavor.

Variation of volatile flavor substances in salt-baked chicken during processing

Salt-baked chicken was a traditional delicacy of Guangdong, but the effects of volatile flavor compounds at different stages of its processing remained unclear. This study utilized sensory analysis, e-nose, and GC–MS to investigate the changes in volatile flavor compounds during the processing of salt-baked chicken. The results indicated significant alterations in volatile flavor compounds at different stages of processing, resulting in flavor transitioning from the original flavor to salty, scorched, and fatty flavor. 75 volatile compounds were identified by GC–MS, with 15 key flavor compounds highlighted based on OAV, including aldehydes, alcohols, terpenes, heterocycles and esters. The research revealed the dynamic changes in volatile flavor compounds throughout the cooking process of salt-baked chicken and emphasized the important role of salt-baked in shaping its distinctive taste profile. These findings provided a theoretical foundation and practical guidance for enhancing and optimizing the authentic taste of this traditional dish, while fostering innovative advancements in prepared cuisine.

Effects of different thermal processing methods on amino acid, fatty acid, and volatile flavor substance contents of Aohan millet (Golden seedling millet)

AbstractAohan millet has been cultivated for 8000 years and has rich nutritional value, such as high‐quality fatty acids and amino acids. Thermal processing is a conventional approach to food preparation. However, the effect of thermal processing on the formation of flavor substances in millet has not been clarified. Therefore, in this study, the effects of three different thermal processing techniques, namely, steaming, stir‐frying, and puffing, on the amino acids, fatty acids, and volatile flavor substances of Aohan millet were investigated using high‐speed automatic amino acid analyzer, headspace solid‐phase microextraction method, combined with gas chromatography–mass spectrometry (HS‐SPME/GC–MS) and gas chromatography (GC) with Aohan millet from Inner Mongolia as the raw material. All three thermal processing methods notably reduced the levels of protein, starch, polyphenols, and flavonoids in Aohan millet when compared to the raw millet (p < .05). Amino acid and fatty acid contents demonstrated an increase in fried and puffed millet relative to steamed millet, with notable distinctions in amino acid and fatty acid contents between these two groups. Following the steaming process, there was a significant increase in the flavor compounds of Aohan millet, rising from 53 to 80, while this increase was not observed in the other two groups. The correlation analysis suggested that the formation of flavor compounds was predominantly influenced by the types and levels of amino acids. The study suggested that different heat treatments affected the amino acid, fatty acid, and more significantly flavor material content and composition of Aohan millet. In conclusion, steaming treatment could retain more nutrients and richer flavor substances; while puffing treatment would enhance amino acid and fatty acid content, which provides a fundamental basis for scientifically guided processing and rational culinary application of Aohan millet.

Investigating the temporal evolution of physicochemical attributes and flavorome profiles in Sichuan shai vinegar utilizing diverse aging techniques

Sichuan shai vinegar (SSV) is an acidic condiment with a long history and unique flavor. Aging is an important production process that determines the unique flavor of shai vinegar. This study compared the differences in physicochemical properties, volatile flavor, and non-volatile flavor substances between the constant temperature aging and natural aging methods of SSV Cupei. The results showed that the total acid and amino acid nitrogen content in naturally aged vinegar was higher than that in constant temperature aged vinegar. Furthermore, 20 different volatile flavor substances and 65 different non-volatile flavor substances were obtained after 21 and 25 days of constant temperature aging and 1, 3, and 5 years of natural aging SSV samples. This indicates that the temperature environment during natural aging was more moderate, allowing acidic compounds to form and stably exist in the aging environment. Correlation analysis further demonstrated that there were more differentiated non-volatile substances significantly related to the Maillard reaction under constant temperature aging condition and related to antioxidant activity under natural aging condition. The results of this study provide a comprehensive understanding of the characteristics and applications of the two aging methods of SSV and guide strategy for factories in the selection of aging methods.

Effects of different reheating methods on lipid oxidation in frozen silver carp fish cakes

SummaryThis study investigated the effect of five different reheating methods (boiling water, steaming, low‐heat microwave at 120 W, medium‐heat microwave at 400 W, high‐heat microwave at 800 W) on lipid oxidation of silver carp fish cake. The changes of lipid content, thiobarbituric acid (TBA) value, acid value (AV), peroxide value (POV), volatile flavour components and fatty acid composition were detected. The results indicated that products reheated with medium‐heat microwave had higher lipid content, lower TBA, AV and POV value. The medium‐heat and high‐heat microwave reheated group had larger variety of volatile flavour substances. Moreover, the relative content of hexanal and heptanal related to unpleasant “overcooked taste” was less, and the relative content of 2‐heptanone, which contributed to the reduction of fishy odour, was more in medium‐heated microwave group. The content of monounsaturated fatty acids in the medium‐heat microwave group was higher than other reheating methods, so as the ratio of unsaturated to saturated fatty acids. Considering all indicators, medium‐heat microwave reheating is more recommended due to its inhibition of fat oxidation.

Effects of Different Roasting Methods on the Quality of Roasted Large Yellow Croaker (Larimichthys crocea).

This study investigated the effects of different roasting methods (45% light wave and 55% microwave roasting, 70% light wave and 30% microwave roasting, 100% light wave roasting, far-infrared roasting, and oven roasting) on the quality of roasted large yellow croaker. The quality was evaluated using sensory evaluation, texture characteristics, color differences, moisture content, and volatile flavor substances. In this context, different roasting methods can affect the color, taste, and flavor of large yellow croaker fish, significantly improving the overall acceptance of roasted fish. The results showed that after 45% light wave and 55% microwave roasting, the elasticity of fish meat was maintained, the hardness of fish meat was reduced, the moisture content and distribution were changed, and the taste was the best. Far-infrared roasting and 45% light wave and 55% microwave roasting had a significant effect on the color of large yellow croaker samples and improved the sensory evaluation score. Forty-six volatile compounds were detected using gas chromatography-mass spectrometry. After roasting, the oxidation and Maillard reactions of lipids and proteins were increased, with the 45% light wave and 55% microwave roasting giving the highest variety of volatile flavor substance products.

Influence of Penicillium lanosum and Staphylococcus equorum on Microbial Diversity and Flavor of Mianning Hams.

Mianning ham is a traditional meat product in China. In this experiment, solid-phase microextraction-gas chromatography (SPME-GC-MS) and high-throughput sequencing were used to study the effects of adding Penicillium lanosum and adding the mixture of Penicillium lanosum and Staphylococcus equorum on the flavor and microbiology of Mianning ham. The results showed that the addition of the ferments resulted in an increase in the abundance of both the dominant bacterial phylum (Thick-walled Bacteria) and the dominant fungal phylum (Ascomycota). The variety of volatile flavor substances and key flavor substances increased after adding fermentation agents. A free amino acid analysis showed that hams from the Penicillium lanosum and Staphylococcus equorum group had significantly higher umami flavor amino acids than the control group and Penicillium lanosum group. Therefore, inoculation with Penicillium lanosum and Staphylococcus equorum favored the dominant bacteria and flavor of Mianning ham.

Effects of the photovoltaic fishery culture model on muscle nutritional quality and volatile flavor compounds of Litopenaeus vannamei

This study used Litopenaeus vannamei to compare the muscle nutritional quality and volatile flavor compounds of animals raised in the photovoltaic fishery culture model (PM) and the common pond breeding model (CM). Amino acids, fatty acids, and volatile flavor substances were identified and analyzed using an automatic amino acid analyzer and headspace solid phase microextraction(HS-SPME) combined with GC/MS. There were no significant differences between the two culture models in terms of general nutrients, mineral contents, and amino acid compositions in the muscles of L. vannamei. In the PM group, the proportion of flavor amino acids in total amino acids was higher. Based on the amino acid score (AAS) and chemical score (CS), it was found that methionine and cystine were the first limiting amino acids in the muscle samples. The essential amino acid index (EAAI) value was approximately 77 for both models, indicating high-quality proteins. The muscles contained nine types of fatty acids, with the PM group showing significantly higher levels of both monounsaturated and total fatty acids. A total of 23 volatile flavor compounds were identified in both models. The contents of 1-nonanal, n-tridecane, and alpha-terpineol were higher when cultured in the PM. Conversely, the contents of hexanal, 2-ethylhexanol, and dipentene were lower in the PM group. The photovoltaic fishery culture model has the potential to enhance income through photovoltaic power generation. In addition, this study found that the fatty acid composition of L. vannamei was improved in the PM, without compromising muscle composition or flavor. These results provide a theoretical basis for evaluating the meat quality of L. vannamei under different culture models and offer data to support and guide the promotion of the PM.

Lipid degradation contributes to flavor formation during air-dried camel jerky processing

Lipids play an important role in flavor formation in meat products. To determine the contribution of lipids to flavor formation during air-dried camel jerky processing, lipid changes were analyzed by UHPLC-Q-Exactive Orbitrap MS/MS in this study, and volatile compounds were identified by HS-SPME-GC-ToF-MS. Results showed that 606 lipid molecules belonging to 30 subclasses were identified and 206 differential lipid molecules were screened out (VIP > 1, P < 0.05); Cer/NS (d18:1/20:0), LPE (18:1), FA (18:0), GlcADG (12:0/24:1), and PE (18:2e/22:5) were identified as potential lipid biomarkers. A total of 96 volatile compounds were also identified, and 16 of these were identified as key aroma compounds in air-dried camel jerky. Meanwhile, 11 differential lipids significantly, negatively correlated with 7 key aroma compounds (P < 0.05) during processing, indicating that the precursors produced by the degradation of lipid molecules were important sources of volatile flavor substances in air-dried camel jerky.

An Evaluation of Pig Type Regarding the Quality of Xuanwei Ham

To determine the influence of pig type (Landrace, Wujin, or Tibetan fragrant) on the quality of Xuanwei ham, we measured the ham pH, color, fat content, and moisture content; used an E-nose (a device intended to detect odors or flavors); and analyzed flavoring substances using headspace solid-phase microextraction–gas chromatography, free amino acids using high-performance liquid chromatography, and microbial diversity using high-throughput sequencing. The ham types differed from each other in these attributes. The moisture and fat contents of Landrace pig ham were significantly lower than those of the other pig types, the brightness values of the Tibetan fragrant pig ham were significantly lower than those of the other pig types, and the redness values of the Landrace and Wujin pig hams were significantly higher than those of the Tibetan fragrant pig ham. The essential amino acid contents, e-wind odor response values, and volatile flavor substances of Wujin pig hams were significantly higher than those of the Tibetan fragrant pig ham, and the relative aldehyde contents of Wujin pig ham were significantly higher than those of the other pig types. The dominant microbial phyla in each ham type were assessed based on the species commonness, composition, and diversity and included taxa such as Actinobacteria and Ascomycetes and thick-walled bacteria such as Orphanomyces, Grass Spirochaetes, and Pseudoalteromonas. The microbial diversity and richness were the greatest in the Wujin pig ham. Of the three pigs, we conclude that the Wujin pig produces the best Xuanwei ham.

Analysis of flavor substances changes during fermentation of Chinese spicy cabbage based on GC-IMS and PCA

This study employed a combination of principal component analysis (PCA) and gas chromatography-ion mobility spectrometry (GC-IMS) to examine the distinctive taste mixtures produced by Chinese spicy cabbage (CSC) fermented at varying temperatures. As the fermentation progressed, the pH gradually decreased and stabilized after the 11 days of fermentation, and the total content of organic acids and short-chain fatty acids increased. A total of 49 volatile mixtures were detected during CSC fermentation and storage for 21 days. These included 7 aldehydes, 6 alcohols, 7 esters, 6 ketones, 5 pyrazines, 4 sulfides, 4 phenols, 2 ethers, 2 olefins, and 1 acid. With time, the content of most volatile flavor substances decreased. PCA of the signal intensities of the volatile chemicals in the samples showed significant differences in the flavor of CSC fermented at different temperatures; consequently, the samples fermented at different temperatures were effectively separated in relatively independent regions of CSC. Therefore, low-temperature fermentation and storage at 4 °C were more suitable for CSC. Based on the identified volatile chemicals, HS-GC-IMS and PCA could effectively construct the flavour fingerprints of CSC samples. This study provided a theoretical basis for improving the fermentation quality of CSC.

Changes in flavour- and taste-presenting substances in Hypsizygus marmoreus mushroom packaged in polypropylene nanofilm

Hypsizygus marmoreus mushroom is known for its pleasant flavour and delicious taste. However, its flavour quality deteriorates rapidly during postharvest storage. In the present work, we explored the dynamic changes in flavour-presenting substances and taste components in H. marmoreus packaged in polyethylene nanofilm (0.05 mm) during low temperature storage (12 days). We used headspace solid-phase microextraction combined with gas chromatography-mass spectrometry to analyse the volatile flavour components; high performance liquid chromatography and liquid chromatography-mass spectrometry to analyse the non-volatile flavour (taste-presenting) substances (e.g., soluble sugars, taste nucleotides, free amino acids, and organic acids); and the relative odour activity value (ROAV) and taste active value (TAV) methods to determine the flavour substances in fresh and stored H. marmoreus. Results revealed that n-octanal, 1-octene-3-one, and 1-octene-3-ol were the characteristic volatile flavour substances, and that trans-2-octenal was the key substance affecting the formation of volatile flavours in fresh H. marmoreus. Trans,trans-2,4-nonadienal, and 3-octanone were the key volatile substances that resulted in flavour deterioration. Among the non-volatile flavour substances, trehalose, 5'-GMP, glutamic acid, alanine, and arginine were the key taste-presenting substances. In addition, oxalic acid and lysine were the key taste substances after H. marmoreus deterioration. These results provided a theoretical basis for rapid quality detection, flavour identification, and shelf-life prediction of H. marmoreus.

The difference analysis of physicochemical indexes and volatile flavor compounds of chili oil prepared from different varieties of chili pepper

Because of its peculiar flavor, chili oil is widely used in all kinds of food and is welcomed by people. Chili pepper is an important raw material affecting its quality, and commercial chili oil needs to meet various production needs, so it needs to be made with different chili peppers. However, the current compounding method mainly relies on the experience of professionals and lacks the basis of objective numerical analysis. In this study, the chroma and capsaicinoids of different chili oils were analyzed, and then the volatile components were determined by gas chromatography-mass spectrometry (GC–MS) and gas chromatography-ion migration spectrometer (GC-IMS) and electronic nose (E-nose). The results showed that Zidantou chili oil had the highest L*, b*, and color intensity (ΔE) (52.76 ± 0.52, 88.72 ± 0.89, and 118.84 ± 1.14), but the color was tended to be greenyellow. Xinyidai chili oil had the highest a* (65.04 ± 0.2). But its b* and L* were relatively low (76.17 ± 0.29 and 45.41 ± 0.16), and the oil was dark red. For capsaicinoids, Xiaomila chili oil had the highest content of capsaicinoids was 2.68 ± 0.07 g/kg, Tianjiao chili oil had the lowest content of capsaicinoids was 0.0044 ± 0.0044 g/kg. Besides, 96 and 54 volatile flavor substances were identified by GC–MS and GC-IMS respectively. And the main volatile flavor substances of chili oil were aldehydes, alcohols, ketones, and esters. A total of 11 key flavor compounds were screened by the relative odor activity value (ROAV). Moguijiao chili oil and Zidantou chili oil had a prominent grass aroma because of hexanal, while Shizhuhong chili oil, Denglongjiao chili oil, Erjingtiao chili oil, and Zhoujiao chili oil had a prominent floral aroma because of 2, 3-butanediol. Chili oils could be well divided into 3 groups by the partial least squares discriminant analysis (PLS-DA). According to the above results, the 10 kinds of chili oil had their own characteristics in color, capsaicinoids and flavor. Based on quantitative physicochemical indicators and flavor substances, the theoretical basis for the compounding of chili oil could be provided to meet the production demand more scientifically and accurately.

Flavor Improvement of Maillard Reaction Intermediates Derived from Enzymatic Hydrolysates of Oudemansiella raphanipes Mushroom.

Maillard reaction intermediate (MRI) was prepared by the enzymatic hydrolysate (EH) of Oudemansiella raphanipes and fructose. The optimal preparation condition of MRIs was obtained when the Maillard reaction parameters were as follows: fructose addition of 5%, reaction time of 60 min, and temperature of 60 °C. E-Tongue results indicated that the umami and saltiness of MRIs were greater than those of Maillard reaction products (MRPs) and EH, and the taste-enhancing ability of MRIs was even more prominent than that of MRPs. E-Nose could obviously distinguish EH, MRIs, and MRPs, and there was an obvious difference between MRPs and MRIs regarding volatile aroma compounds. A total of 35 volatile flavor substances were identified among the three samples, including 6 alcohols, 13 aldehydes, 9 ketones, 2 esters, and 5 other compounds. Overall, MRIs could avoid the production of complete reaction products with an inferior flavor, and further enhance the umami taste.

Quality Assessment of Loquat under Different Preservation Methods Based on Physicochemical Indicators, GC–MS and Intelligent Senses

To explore the effects of different preservation methods on the quality of loquat after fresh-keeping treatment, various preservation techniques were employed. These included natural preservation (NP), vacuum freezing preservation (VFP), vacuum at room temperature preservation (VP) and freezing preservation (FP). The quality assessment involved analyzing the effects of these preservation methods using physicochemical indexes, a colorimeter, an electronic nose (E-nose), an electronic tongue (E-tongue) and gas chromatography–mass spectrometry (GC–MS). The results showed minor differences in loquat quality under different preservation methods, with sensory scores ranging from 55 to 78 and ΔE values ranging from 11.92 to 18.59. Significant variations were observed in moisture content (ranging from 53.20 g/100 g to 87.20 g/100 g), calorie content (ranging from 42.55 Kcal/100 g to 87.30 Kcal/100 g), adhesion (ranging from 0.92 to 1.84 mJ) and hardness (ranging from 2.97 to 4.19 N) (p &lt; 0.05). Additionally, the free amino acid content varied from 22.47 mg/g to 65.42 mg/g. GC–MS analysis identified a total of 47 volatile flavor substances in varieties of loquats, including 13 aldehydes, 9 esters, 6 ketones, 2 acids, 3 alcohols, 2 phenols, 3 pyrazines, 1 furan and 8 other substances. The relative content of aldehydes was significantly higher than that of other chemicals. The VFP and FP samples exhibited higher aldehyde content compared to the NP and VP samples. Moreover, Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) revealed 18 marked compounds that could differentiate between 5 loquat species. Analysis using E-nose and E-tongue indicated significant changes in the olfactory and gustatory senses of loquats following preservation. The VFP samples demonstrated the most effective preservation of loquat quality with minimal impact. This study provides some theoretical guidance for the home preservation of loquats.

Recent advances and challenges in the interaction between myofibrillar proteins and flavor substances.

Myofibrillar proteins are an important component of proteins. Flavor characteristics are the key attributes of food quality. The ability of proteins to bind flavor is one of their most fundamental functional properties. The dynamic balance of release and retention of volatile flavor compounds in protein-containing systems largely affects the sensory quality and consumer acceptability of foods. At present, research on flavor mainly focuses on the formation mechanism of flavor components, while there are few reports on the release and perception of flavor components. This review introduces the composition and structure of myofibrillar proteins, the classification of flavor substances, the physical binding and chemical adsorption of myofibrillar proteins and volatile flavor substances, as well as clarifies the regulation law of flavor substances from the viewpoint of endogenous flavor characteristics and exogenous environment factors, to provide a theoretical reference for the flavor regulation of meat products.

Based on HPLC and HS-GC-IMS Techniques, the Changes in the Internal Chemical Components of Schisandra chinensis (Turcz.) Baill. Fruit at Different Harvesting Periods Were Analyzed.

Schisandra chinensis, as a traditional Chinese herbal medicine, has clear pharmacological effects such as treating asthma, protecting nerves and blood vessels, and having anti-inflammatory properties. Although the Schisandra chinensis fruit contain multiple active components, the lignans have been widely studied as the primary pharmacologically active compound. The volatile chemical components of Schisandra chinensis include a large amount of terpenes, which have been proven to have broad pharmacological activities. However, when to harvest to ensure the highest accumulation of pharmacologically active components in Schisandra chinensis fruits is a critical issue. The Schisandra chinensis fruit trees in the resource nursery were all planted in 2019 and began bearing fruit in 2021. Their nutritional status and tree vigor remain consistently good. The content of lignans and organic acids in the fruits of Schisandra chinensis over seven different harvest periods was tested, and the results of high-performance liquid chromatography (HPLC) indicated that the lignan content was higher, at 35 mg/g, in late July, and the organic acid content was higher, at 72.34 mg/g, in early September. If lignans and organic acids are to be selected as raw materials for pharmacological development, the harvest can be carried out at this stage. Using HS-GC-IMS technology, a total of 67 volatile flavor substances were detected, and the fingerprint of the volatile flavor substances in the different picking periods was established. It was shown by the results that the content of volatile flavor substances was the highest in early August, and 16 flavor substances were selected by odor activity value (OAV). The variable importance in projection (VIP) values of 16 substances were further screened, and terpinolene was identified as the key volatile flavor substance that caused the aroma characteristics of Schisandra chinensis fruit at different harvesting periods. If the aroma component content of Schisandra chinensis fruit is planned to be used as raw material for development and utilization, then early August, when the aroma component content is higher, should be chosen as the time for harvest. This study provides a theoretical basis for the suitable harvesting time of Schisandra chinensis for different uses, and promotes the high-quality development of the Schisandra chinensis industry.

Impact of non-Saccharomyces yeasts derived from traditional fermented foods on beer aroma: Analysis based on HS-SPME-GC/MS combined with chemometrics

In recent years, numerous studies have demonstrated the significant potential of non-Saccharomyces yeasts in aroma generation during fermentation. In this study, 134 strains of yeast were isolated from traditional fermented foods. Subsequently, through primary and tertiary screening, 28 strains of aroma-producing non-Saccharomyces yeast were selected for beer brewing. Headspace-solid phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC–MS) and chemometrics were employed to analyze the volatile flavor substances in beer samples fermented using these strains. Chemometric analysis revealed that distinct species of non-Saccharomyces yeast had a unique influence on beer aroma, with strains from the same genus producing more similar flavor profiles. Accordingly, 2,6-nonadienal, 1-pentanol, phenyl ethanol, isoamyl acetate, ethyl caprate, butyl butyrate, ethyl propionate, furfuryl alcohol, phenethyl acetate, ethyl butyrate, ethyl laurate, acetic acid, and 3-methyl-4 heptanone were identified as the key aroma compounds for distinguishing among different non-Saccharomyces yeast species. This work provides useful insights into the aroma-producing characteristics of different non-Saccharomyces yeasts to reference the targeted improvement of beer aroma.