Use of yeast strain QGXH1 in preparation of ethyl acetate, iridin, and ethyl linolenate

Abstract

This invention belongs to the field of food microbiology technology, specifically relating to the application of yeast strain QGXH1 in the preparation of ethyl acetate, iris glycol, and ethyl linolenate. The yeast strain QGXH1 was deposited on January 29, 2024, at the China General Microbiological Culture Collection Center (CGMCC), accession number CGMCC No. 29805; deposit address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing; classification and nomenclature: *Saccharomyces cerevisiae*. Saccharomyces cerevisiae The plum vinegar prepared by fermentation with yeast strain QGXH1 showed a significant increase in the content of ethyl acetate, ethyl palmitate, ethyl decanoate, linolenic acid, and ethyl hexadecanoate. In addition, when yeast strain QGXH1 was co-fermented with green tea to prepare plum vinegar, the nutritional components increased with iris glycol and ethyl linolenic acid, which greatly enriched the aroma components and nutrients of the plum vinegar.

Description

Technical Field

[0001] This invention belongs to the field of food microbiology technology, specifically relating to the application of yeast strain QGXH1 in the preparation of ethyl acetate, iris glycol, and ethyl linolenate. Background Technology

[0002] Intrahepatic cholestasis is a serious liver disease caused by impaired bile secretion and excretion. It can be triggered by genetics, drug toxicity, or infection, and clinical manifestations include jaundice, itching, and abnormal liver function. Current treatments primarily rely on cholecystokinin (CCK) drugs, such as ursodeoxycholic acid (UDCA) and phenobarbital. However, these treatments have limited efficacy and are often accompanied by gastrointestinal discomfort, drug resistance, or increased liver burden due to long-term use. Therefore, developing novel, safe, and effective treatments has become an important direction in medical research. Meanwhile, functional foods and beverages are gaining increasing attention due to their natural properties and multiple health benefits. Plum vinegar contains acetic acid, organic acids, amino acids, vitamins, and antioxidants, and has effects such as promoting digestion, regulating blood sugar, improving metabolism, and antioxidation. However, existing plum vinegar products mainly target general health needs and lack functional designs specifically for liver diseases such as intrahepatic cholestasis. For example, the traditional effects of plum vinegar are mostly focused on aiding digestion and antioxidation, failing to directly address the problem of bile metabolism disorders. Iridoids are a class of monoterpenoid secondary metabolites widely found in plants, and have attracted attention in recent years due to their diverse biological activities. These compounds are mainly used in plants for defense against pests and pathogens, while also demonstrating potential in the medical field for anti-inflammatory, antioxidant, antibacterial, and metabolic regulation. A study published in *Planta Medica* in 1992 by Mizogμchi et al. (Choleretic effects of alpha-iridodiolon experimentally induced intrahepatic cholestasis) reported the significant choleretic effect of alpha-iridodiol in an experimental model of intrahepatic cholestasis. This study induced intrahepatic cholestasis in rats by intravenous injection of a lymphokine called a "cholestatic factor," resulting in a significant reduction in bile flow and bile acid excretion. Administration of α-iridodiol significantly inhibited the reduction in bile flow and bile acid excretion, and similar bile-promoting effects were observed in normal rats. Summary of the Invention

[0003] This invention provides the application of yeast strain QGXH1 in the preparation of ethyl acetate. This strain can increase the content of ethyl acetate, ethyl palmitate, ethyl decanoate, linolenic acid, and ethyl 9-hexadecanoate in plum vinegar. When yeast strain QGXH1 is co-fermented with green tea to prepare plum vinegar, the nutritional components are increased, including iridium glycol, ethyl linolenic acid, glyoxylic acid, trans-9,12-octadecadienoic acid, β-methyl levulinic acid, 2-methoxy-3-prop-2-enylphenol, 1-butanol, ethyl octanoate, and methyl 10-oxohexadecanoate, thus greatly enriching the aroma substances and nutritional components of plum vinegar.

[0004] The technical solution of this application is as follows:

[0005] The first objective of this application is to protect the application of yeast strain QGXH1 in the preparation of ethyl acetate. The *Saccharomyces cerevisiae* strain QGXH1 was deposited on January 29, 2024, at the China General Microbiological Culture Collection Center (CGMCC), accession number CGMCC No. 29805; deposit address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing; classification and nomenclature: *Saccharomyces cerevisiae*. Saccharomyces cerevisiae .

[0006] According to specific embodiments of this application, it also includes acetic acid bacteria.

[0007] According to a specific embodiment of this application, the yeast strain QGXH1 is added via fermentation broth.

[0008] The second objective of this application is to protect the application of yeast strain QGXH1 in the preparation of iris diol through fermentation with green tea.

[0009] The third objective of this application is to protect the application of yeast strain QGXH1 in the preparation of ethyl linoleate through fermentation with green tea.

[0010] Strain preservation information:

[0011] Preservation institution: China General Microbiological Culture Collection Center, China Committee on the Preservation and Management of Microbial Cultures;

[0012] Accession number: CGMCC No. 29805;

[0013] Deposit date: January 29, 2024;

[0014] Address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing;

[0015] Taxonomic nomenclature: Saccharomyces cerevisiae Saccharomyces cerevisiae .

[0016] Beneficial effects of the invention

[0017] The plum vinegar fermented using yeast strain QGXH1 showed increased levels of ethyl acetate, ethyl palmitate, ethyl decanoate, linolenic acid, and ethyl hexadecanoate. Specifically, the ethyl acetate content increased by 11,815,122.2 μg / L, the ethyl palmitate content increased by 7,420.3 μg / L, the ethyl decanoate content increased by 1,391.5 μg / L, the linolenic acid content increased by 4,558.4 μg / L, and the ethyl hexadecanoate content increased by 1,351 μg / L.

[0018] Compared with plum vinegar prepared by fermentation using yeast strain QGXH1, plum vinegar prepared by co-fermentation of green tea with yeast strain QGXH1 has the following newly added nutrients: iris glycol, ethyl linoleate, glyoxylic acid, trans-9,12-octadecadienoic acid, β-methyl levulinic acid, 2-methoxy-3-prop-2-enylphenol, 1-butanol, ethyl octanoate, and methyl 10-oxohexanoate. Among them, the content of iris glycol increased by 170.9 μg / L, and the content of ethyl linoleate increased by 320 μg / L. The content of glyoxylic acid increased by 595.8 μg / L, trans-9,12-octadecadienoic acid increased by 433.4 μg / L, β-methyl levulinic acid increased by 258.6 μg / L, 2-methoxy-3-prop-2-enylphenol increased by 78.6 μg / L, 1-butanol increased by 46.5 μg / L, ethyl octanoate increased by 39.8 μg / L, and methyl 10-oxohexadecanoate increased by 31.9 μg / L. Attached Figure Description

[0019] Figure 1 Chromatograms of brewer's yeast BY4741, yeast strain QGXH1, yeast strain QGXH1 and green tea fermented plum vinegar products. Detailed Implementation

[0020] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments. Unless otherwise specified, the materials, reagents, etc., used in the embodiments and experimental examples of the present invention are all conventional products obtained through commercial channels; unless otherwise specified, the methods used in the embodiments and experimental examples of the present invention are all conventional methods.

[0021] The construction process of the genetically engineered yeast strain QGXH1 is described in Chinese patent CN118006476A.

[0022] YPD solid culture medium: Weigh 2g glucose, 2g peptone, 1g yeast extract, and 2g agar powder and dissolve them in 100mL of distilled water.

[0023] YPD liquid culture medium: Weigh 2g glucose, 2g peptone and 1g yeast extract and dissolve in 100mL distilled water.

[0024] YPG galactose liquid medium: Weigh 2g galactose, 2g peptone, and 1g yeast extract and dissolve them in 100mL of distilled water.

[0025] Example 1

[0026] The preparation method of yeast strain QGXH1 fermentation broth includes the following steps:

[0027] Streak yeast strain QGXH1 onto a YPD solid medium plate. After single colonies grow on the plate, pick a single colony and inoculate it into a test tube containing 3 mL of YPD liquid medium. Incubate in a constant temperature shaker (30℃, 220 r / min) until the OD600 value is about 0.5, completing the first activation. Then, transfer 1% of the inoculum to an Erlenmeyer flask containing 100 mL of YPG galactose liquid medium for a second activation culture (30℃, 220 r / min) until the OD600 value is about 1.5, which completes the preparation of the fermentation broth.

[0028] Experiment Example 2

[0029] Yeast strain QGXH1 is used for liquid fermentation of plum vinegar, including the following steps:

[0030] (1) Select 1kg of fresh plums and squeeze them into juice. Add 1g of pectinase (from Shanghai Maclean Biological Reagent Co., Ltd.), and filter the juice with gauze after 2h in a water bath at 55℃. Adjust the sugar content to 20 with white sugar and divide the plum juice into experimental group and control group.

[0031] (2) 40 mL of yeast strain QGXH1 fermentation broth prepared in Example 1 was added to the experimental group, and 40 mL of activated brewing yeast BY4741 (from Beijing Cooler Technology Co., Ltd.) was added to the control group. Alcoholic fermentation was carried out at 17℃. After 7 days of fermentation, plum wine was obtained.

[0032] The activation method of Saccharomyces cerevisiae BY4741 is as follows: streak Saccharomyces cerevisiae BY4741 onto a YPD solid medium plate. After a single colony grows on the plate, pick a single colony and inoculate it into a test tube containing 100 mL of YPD liquid medium. Incubate in a constant temperature shaker (30℃, 220 r / min) until the OD600 value is about 0.5, and the activation is complete.

[0033] (3) Adjust the alcohol content of the experimental group and the control group to 7%, weigh 1g of Acetobacter acetic acid Hu Niang 1.01 bacterial powder (from Beijing Baocang Biotechnology Co., Ltd.) and inoculate it into the plum wine in step (2) for acetic acid fermentation;

[0034] (4) Samples from both the control and experimental groups were acidified for 7 days in a shaker at 30℃ and 190 r / min, and then analyzed by GC-MS and high-performance gas chromatography-mass spectrometry. Results are shown in […]. Figure 1 ,from Figure 1 It can be seen that the plum vinegar fermented by yeast strain QGXH1 has a significantly increased content of flavor compounds compared with the plum vinegar fermented by yeast BY4741.

[0035] Experimental Example 3

[0036] Yeast strain QGXH1 is used in conjunction with green tea for liquid fermentation of plum vinegar, including the following steps:

[0037] (1) Weigh 10g of fresh green tea leaves and dry them in an 80℃ oven to remove excess moisture until they are semi-dry. Stir-fry them in a brand new iron wok (without any oil) for 5 hours, being careful to rub them while stir-frying. Dry them in an oven and then soak them in 100 mL of 90℃ hot water for 1 hour to concentrate the tea to 80 mL. Filter the tea to obtain the tea soup.

[0038] (2) Select 1 kg of fresh plums and squeeze them into juice. Add 1 g of pectinase (from Shanghai Maclean Biological Reagent Co., Ltd.) and water bath at 55℃ for 2 h. Filter with gauze to obtain plum juice. Adjust the sugar content of the obtained plum juice to 20 with white sugar.

[0039] (3) Divide the plum juice into an experimental group and a control group; mix the experimental group with the tea soup from step (1), and do not treat the control group.

[0040] (4) The experimental group and the control group were inoculated with 40 mL of yeast strain QGXH1 fermentation liquid for alcoholic fermentation. After 7 days of fermentation, plum wine was obtained. The alcohol content was adjusted to 7%, and 1 g of Acetobacter acetic acid Hu Niang 1.01 bacterial powder (from Beijing Baocang Biotechnology Co., Ltd.) was weighed and inoculated into the plum wine for acetic acid fermentation.

[0041] (4) Samples from both the control and experimental groups were acidified for 7 days in a shaker at 30℃ and 190 r / min, and then analyzed by GC-MS and high-performance gas chromatography-mass spectrometry. Results are shown in […]. Figure 1 ,from Figure 1 It can be seen that the plum vinegar fermented by yeast strain QGXH1 has a significantly increased content of flavor compounds compared with the plum vinegar fermented by brewer's yeast BY4741. The combined effect of yeast strain QGXH1 and green tea can further enhance the variety of flavor compounds in plum vinegar.

[0042] Implementation Results Example

[0043] Analysis of the component detection results of plum vinegar obtained in Examples 1, 2, and 3.

[0044] Table 1. GC-MS detection results of plum vinegar obtained in Examples 2 and 3

[0045]

[0046] Tests revealed that the experimental group differed from the control group in the following ways:

[0047] Compared with the control group, the experimental group in Example 2 had the following increases: ethyl acetate content increased to 11815122.21 μg / L, ethyl palmitate content increased to 7420.3 μg / L, linoleic acid content increased to 4561.4 μg / L, ethyl 9-hexadecanoate content increased to 1351 μg / L, and ethyl decanoate content increased to 1391.5 μg / L.

[0048] Compared to the control group, the experimental group in Example 3 had lower levels of flavor compounds such as ethyl acetate, ethyl palmitate, linoleic acid, ethyl hexadecanoate, and ethyl decanoate. However, the experimental group had an increased variety of flavor compounds and nutrients, including iris glycol, ethyl linolenate, glyoxylic acid, trans-9,12-octadecadienoic acid, β-methyl levulinic acid, 2-methoxy-3-prop-2-enylphenol, 1-butanol, ethyl octanoate, and methyl 10-oxohexadecanoate, among others.

[0049] Data from the experimental and control groups in Example 2 demonstrate that yeast strain QGXH1 significantly increases the content of flavor compounds in plum vinegar compared to brewer's yeast BY4741. Data from the experimental and control groups in Example 3 demonstrate that the combined effect of yeast strain QGXH1 and green tea can further enhance the variety of flavor compounds and nutrients in plum vinegar.

[0050] Ethyl linolenic acid (ALA) is a plant-based omega-3 fatty acid commonly used as a dietary supplement to help improve blood lipids and support cardiovascular health. In some food processing, ALA may be used as a flavor enhancer or other ingredient to improve flavor.

Claims

1. The application of yeast strain QGXH1 in the preparation of ethyl acetate from plum vinegar by liquid fermentation, characterized in that, The yeast strain QGXH1 was deposited on January 29, 2024, at the China General Microbiological Culture Collection Center (CGMCC), accession number CGMCC No. 29805; deposit address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing; classification and nomenclature: *Saccharomyces cerevisiae*. Saccharomyces cerevisiae ; The yeast strain QGXH1 was added via fermentation broth.

2. The application of yeast strain QGXH1 in combination with green tea in the preparation of iridodiol and ethyl linoleate from plum vinegar by liquid fermentation, characterized in that... The yeast strain QGXH1 was deposited on January 29, 2024, at the China General Microbiological Culture Collection Center (CGMCC), accession number CGMCC No. 29805; deposit address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing; classification and nomenclature: *Saccharomyces cerevisiae*. Saccharomyces cerevisiae; The yeast strain QGXH1 was added via fermentation broth.

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