A method for increasing 3-octanone, a key aroma component of shiitake mushrooms, based on static magnetic field

Abstract

The invention discloses a method for increasing 3-octanone, a key aroma component of flower mushrooms, based on a static magnetic field, and belongs to the technical field of food detection and analysis. The present application treats fresh-cut flower mushrooms with a static magnetic field of 0 to 10 mt, and uses headspace-gas-ion-ion mobility spectrometry analysis and principal component analysis to obtain the change law of key aroma components of flower mushrooms. The present application identifies a total of 43 odor substances from flower mushrooms. Among them, 3-octanone accounts for 49.1% and 90.1% of total odor substances and total ketones, respectively, and is a key aroma substance in flower mushrooms. Dicing treatment results in a significant decrease in the concentration of 3-octanone monomers and dimers in flower mushrooms. Exposure to a 2mt static magnetic field significantly increases the concentration of 3-octanone monomers and dimers in diced flower mushrooms, and is significantly higher than other magnetic field intensities. A 2mt static magnetic field helps to enhance the aroma of fresh-cut flower mushrooms, and provides a certain technical reference and theoretical basis for using a static magnetic field to improve the aroma quality of fresh-cut mushrooms.

Description

Technical Field

[0001] The invention belongs to the technical field of food detection and analysis, and particularly relates to a method for increasing 3-octanone, a key aroma component of shiitake mushrooms, based on a static magnetic field. Background Art

[0002] Flower mushroom (Lentinus edodes (Berk.) sing) is the best among shiitake mushrooms, and its cap is named after the pattern on it. Flower mushroom is known as a delicacy on banquets for its thick flesh, tender texture and delicious taste. The unique aroma of shiitake mushrooms mainly comes from eight-carbon compounds and sulfur-containing compounds, while other substances such as aldehydes, acids, ketones and esters play a role in blending and assisting in the aroma. Fresh-cut vegetables (clean vegetables) have the advantages of being natural, hygienic, highly utilized and convenient to eat. They are deeply favored by industries such as fast food, retail and catering, and have become a new trend in the vegetable consumption market. However, fresh-cut processing often aggravates the quality deterioration of vegetable flavor loss, browning, nutrient degradation and other quality problems, thereby reducing the commercial value of vegetable products. Therefore, maintaining or improving the aroma quality of fresh-cut flower mushrooms remains a problem that needs to be solved urgently.

[0003] Magnetic fields have the advantages of being safe, residue-free, pollution-free, and easy to control, and have attracted much attention from researchers in fruit and vegetable preservation. At present, magnetic fields, as a new type of physical preservation technology, have made positive progress in preserving fruits and vegetables and extending their storage period. For example, they inhibit the reproduction of spoilage bacteria and mildew, delay softening and browning, inhibit respiration and transpiration, maintain the integrity of nutrients and cell membranes, and enhance antioxidant activity. However, there is a "window effect" in the action of magnetic fields, that is, positive effects can only be produced under the action of magnetic fields with specific characteristics and parameters. In addition, the preservation of fruits and vegetables is not always consistent with the preservation of flavor. For example, fruits and vegetables are "not good to eat" and have peculiar smells and strange tastes.

[0004] Headspace-gas phase-ion mobility spectrometry (HS-GC-IMS) is a new type of analytical technology with high sensitivity, high efficiency, easy operation and simple sample preparation. It has been successfully used in the identification and quantitative analysis of volatiles in fruits and vegetables. Principal components analysis (PCA) is a method of statistical analysis and simplification of data sets. It uses orthogonal transformation to linearly transform the observed values ​​of a series of possibly related variables, thereby projecting them into the values ​​of a series of linearly unrelated variables, which are called principal components. At present, the flavor characteristics of flower mushrooms and the changing laws and window conditions of their molecular composition under the action of magnetic fields have not been reported. Summary of the invention

[0005] In view of the above problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method for increasing 3-octanone, a key aroma component of shiitake mushrooms, based on a static magnetic field.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for increasing 3-octanone, a key aroma component of shiitake mushrooms, based on a static magnetic field, comprises the following steps:

[0008] 1) Select the mushrooms that are intact, fresh, and free of mechanical damage;

[0009] 2) Cut off the stalk of the flower mushroom, cut the flower mushroom fresh, and control the static magnetic field intensity to 0-10mt;

[0010] 3) HS-GC-IMS and PCA analysis were performed to obtain the main aroma components of shiitake mushrooms and screen out the key aroma components.

[0011] Furthermore, the present application dices the flower mushrooms; the size of the flower mushroom dices is 2 to 8 mm 3 .

[0012] As a preference, the size of the diced mushroom is 5 mm 3 .

[0013] Furthermore, the static magnetic field intensity is controlled to be 2-8 mt and the duration is 1 hour.

[0014] Preferably, the static magnetic field intensity is controlled to be 2 mt and the duration is 1 h.

[0015] Furthermore, the HS-GC-IMS analysis specifically includes the following steps: the fresh-cut flower mushrooms are transferred to the headspace bottle at a dosage ratio of 1 g:4 mL, incubated at 55 °C for 15 min under oscillating heating mode, the headspace gas is automatically injected into the GC, and separated by a 60 °C MXT-5 column; the volatiles are ionized in the IMS ion chamber and driven to the migration tube for separation at 45 °C by nitrogen flow; the total analysis time is 20 min.

[0016] Furthermore, PCA analysis was performed based on peak volume; the R of the established PCA model was 2 X and Q 2 They are 0.985 and 0.65 respectively.

[0017] Furthermore, the main aroma components of flower mushrooms include 3-octanone, 2-butanone, 2-methylbutanal, and ethyl propionate.

[0018] Preferably, the key aroma component of shiitake mushroom is 3-octanone.

[0019] The application of the above method in the preservation of flower mushrooms.

[0020] The method is used for maintaining the flavor of fresh-cut shiitake mushrooms.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This application combines HS-GC-IMS and PCA to analyze the effects of different static magnetic field intensities on the composition of odor substances in fresh-cut flower mushrooms. A total of 43 odor substances were identified from flower mushrooms. Among them, 3-octanone (mushroom aroma) accounted for 49.1% and 90.1% of the total odor substances and total ketones, respectively, which is much higher than other odor components and is the key aroma substance in flower mushrooms. The dicing treatment resulted in a significant decrease in the concentration of 3-octanone monomers and dimers in flower mushrooms (P < 0.05). Exposure to a 2mt static magnetic field significantly increased the concentration of 3-octanone monomers and dimers in diced flower mushrooms, and was significantly higher than other magnetic field intensities (P < 0.05). It can be seen that a 2mt static magnetic field helps to enhance the aroma of fresh-cut flower mushrooms, providing a certain technical reference and theoretical basis for using static magnetic fields to improve the aroma quality of fresh-cut mushrooms. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 HS-GC-IMS analysis flow chart for this application;

[0024] Figure 2 This is a two-dimensional spectrum of typical odor substances of shiitake mushrooms;

[0025] Figure 3 The composition (A) and content (B) of odor substances in different treatments of flower mushrooms;

[0026] Figure 4 The fingerprints of the odor substances of different treatments of shiitake mushrooms;

[0027] Figure 5 This is the PCA score diagram of the odor substances of the different treatments of the shiitake mushroom;

[0028] Figure 6 This is a graph showing the effects of different treatments on the characteristic odor substances of Oyster mushroom. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with specific embodiments. These embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit and substance of the present invention, the modification or replacement of the inventive method, step or condition, all belong to the scope of the present invention. In the following examples, if there is no special explanation, the technical means used in the examples are conventional means well known to those skilled in the art.

[0030] Example 1

[0031] Flower mushrooms were purchased from their place of origin (Nanyang City, Henan Province) in January 2022. Flower mushrooms with intact appearance, freshness, no mechanical damage, and uniform size were selected as experimental materials. After the flower mushrooms were equilibrated to room temperature, the flower mushroom stems were cut off and cut into about 5mm 330g of diced mushrooms were weighed and placed in different static magnetic field strengths (2mt, 4mt, 6mt and 8mt) at room temperature (10℃) for 1h, as magnetic field groups, namely 2mt group, 4mt group, 6mt group and 8mt group. At the same time, 30g of diced samples were weighed and placed at room temperature (10℃) for 1h, as diced group. The whole shiitake mushrooms were used as the control group.

[0032] The volatile compounds of shiitake mushrooms were analyzed by FlavourSpec flavor analyzer equipped with gas chromatography (GC) and ion mobility spectrometry (IMS). The GC-IMS analysis process was as follows: Figure 1 As shown. 5.0 g of diced sample was transferred to a 20 mL headspace vial and incubated for 15 min in oscillating heating mode (55 °C). 500 μL of headspace gas was automatically injected into the GC and separated by a 60 °C MXT-5 column (15 mL×0.53 mm, 1.0 μm film thickness). Subsequently, the volatiles were ionized in the IMS ion chamber (300 MBq in positive ion mode) and driven to the migration tube for separation at 45 °C by a nitrogen flow (99.999%). The total HS-GC-IMS analysis time was 20 min. The fingerprint of the sample volatiles was generated by the Reporter plug-in and Gallery Plot plug-in configured in the Laboratory Analytical Viewer (LAV) software. Using the orthoketone compound C4-C9 (Sinopharm Chemical Reagent Beijing Co., ltd., Beijing, China) as an external standard, a standard curve was established and the retention time (Rt) of each volatile was calculated. The volatiles were qualitatively identified by comparing the Rt and migration time (Dt, relative value of the RIP peak) with those of the standards in the NIST and IMS databases in the GC×IMS Library Search software.

[0033] Using SIMCA-p 14.1 software (MKS Umetrics AB, Sweden) after the data were standardized by Ctr method, and then multivariate statistical analysis PCA analysis was performed. SPSS 24.0 software (SPSS Inc., Chicago, IL, USA) was used for one-way analysis of variance followed by multiple comparison analysis. The significance level was P < 0.05. Data are expressed as mean ± standard error. OriginPro 2022b (OriginLab Corporation, Northampton, MA, USA) was used to plot the data.

[0034] 1. Qualitative analysis of odor substances

[0035] like Figure 2 As shown in the peak signals, a total of 56 volatile substances were detected from different samples. The Rt and Dt of the selected peaks were compared with the NIST and IMS databases in the GC×IMS Library Search software, and a total of 43 odor substances were identified (Table 1). Figure 3 The differences in the types and contents of odor substances in different samples are intuitively displayed. Figure 3 (A) shows that there are abundant odor substances in Oleander, which belong to 7 categories, including 10 alcohols, 8 aldehydes, 8 ketones, 11 esters, 2 sulfides, 2 acids, 2 pyrroles and 13 other unidentified substances.

[0036] Figure 3 (B) shows that the total content of ketones in the control group was the highest, up to 54.5%, while the total content of alcohols, aldehydes and esters was relatively low, ranging from 9.5% to 13.7%. Other substances with very low total content, such as sulfides (0.2%), organic acids (0.3%), pyrroles (1.5%), etc., contributed little to the final aroma quality of flower mushrooms. The total content of ketones in the diced group (12.4%) was significantly reduced, while the total content of alcohols, aldehydes, esters and other substances (19.2% to 21.2%) were significantly increased. It can be seen that the dicing process seriously affected the composition of the original odor substances in flower mushrooms. The total content of ketones in the 2mt group was 47.4%, significantly higher than that in the diced group and other magnetic field groups (15.5% to 20.7%), while the total content of alcohols, aldehydes, esters and other substances (11.9% to 14.2%) were significantly lower than those in the diced group and other magnetic field groups (15.6% to 23.5%). It can be seen that the total content of odor substances in the 2mt group was closer to that of the control group than in other groups.

[0037] Table 1 Identified odor and flavor substances in shiitake mushrooms and their odor descriptions

[0038]

[0039]

[0040]

[0041] 2. Fingerprint Analysis

[0042] like Figure 4As shown in the figure, compared with the control group, the dicing treatment seriously affected the concentration of various odor substances in the flower mushroom. The concentrations of ketone substances such as 3-octanone, 1-octen-3-one, 2-butanone, and 2-heptanone were significantly reduced, and the concentrations of different types of substances such as alcohols, aldehydes, and esters increased or decreased to varying degrees. In the magnetic field group, the concentrations of substances (except benzaldehyde) reduced by dicing treatment in the 2mt group showed a significant increasing trend, tending to the control group. In addition, the concentrations of 3-octanone monomers and dimers and alcohols such as ethanol, isopropanol, and n-pentanol monomers and dimers among these substances were significantly higher than those in other magnetic field groups. The concentrations of ketones such as 2-butanone and 1-octen-3-one, aldehydes such as 2-methylbutanal, heptanal, and hexanal, and ethyl propionate were significantly higher than those in the 4mt group and the 8mt group, and there was no significant difference with the 6mt group. On the contrary, the concentrations of alcohols such as 2-methyl-2-propanol and 1-propanethiol dimer, butyraldehyde, and esters such as propyl acetate, propyl butyrate monomer and dimer, ethyl 2-methylbutyrate monomer and dimer, and ethyl 2-methylpropionate monomer and dimer in the 2mt group were significantly lower than those in the diced group, but these substances were closer to the control group than those in the other magnetic field groups. In summary, the 2mt static magnetic field can maintain the original odor composition of fresh-cut mushrooms to the greatest extent, especially ketones such as 3-octanone and 1-octen-3-one.

[0043] 3. Analysis of characteristic odor substances

[0044] The PCA analysis was performed using the signal peak intensity (peak volume) to evaluate the regularity and differences of odor substances among different samples. The R of the PCA model 2 X and Q 2 They are 0.985 and 0.65 respectively, indicating that the model's fitting degree and ability to predict the differences in odor substances of different samples are both ideal. The total contribution rate of the first principal component (PC1, 97.1%) and the second principal component (PC2, 1.5%) is 98.6%, which is greater than 85%, indicating that the first two principal components contain most of the sample information and are sufficient to characterize the overall information of the sample. As shown in the score diagram ( Figure 5 ), along PC1, the control group and the 2mt group were significantly separated from the other groups; along PC2, the diced group, the 4mt group, the 6mt group, and the 8mt group were significantly separated; along PC1 and PC2, the control group and the 2mt group were separated. The results showed that the PCA model could ideally distinguish the differences between different samples. Through the loading analysis, it was found that a total of 13 characteristic odor substances were screened out, including 3-octanone monomer and dimer, 2-butanone, acetophenone, 2-methyl-2-propanol, 1-propanethiol dimer, 2-methylbutanal, benzaldehyde monomer, propyl acetate, ethyl propionate, and dimethyl trisulfide.

[0045] Table 2 and Figure 6The effects of different treatments on the 13 characteristic odor substances screened out from flower mushrooms and their significance levels were intuitively displayed. The dicing treatment significantly reduced the concentrations of 3-octanone monomer and dimer, 2-butanone, 2-methylbutanal, ethyl propionate and benzaldehyde monomer in flower mushrooms (P < 0.05). Among them, the signal peak intensities of 3-octanone monomer and dimer in the control group were as high as 21299.6 and 6049.2, respectively, which were much higher than other substances. And the proportion of 3-octanone in the total odor substances and total ketones was as high as 49.1% and 90.1%, respectively. 3-octanone has a mushroom aroma (Table 1). It can be seen that 3-octanone is a key substance in the formation of flower mushroom aroma, and it is also a characteristic substance that causes significant differences between different groups. In addition, 2-butanone (5128.2), 2-methylbutanal (2332.7), propyl acetate (1324.3), and ethyl propionate (1890.1) have high signal peak intensities and are also the main substances in the formation of flower mushroom aroma (Table 1). The significant reduction in the concentration of the above main aroma substances (especially 3-octanone) will cause a serious loss of aroma in the diced sample.

[0046] In the magnetic field groups, the concentrations of 3-octanone monomer, 2-butanone, 2-methylbutanal and ethyl propionate in the 2mt group were significantly higher than those in the diced group (P < 0.05), and there was no significant difference with the control group (P > 0.05). Among them, the concentration of 3-octanone monomer was also significantly higher than that in the other magnetic field groups (P < 0.05). The concentrations of 2-butanone, 2-methylbutanal and ethyl propionate were significantly higher than those in the 4mt group and the 8mt group (P < 0.05), and there was no significant difference with the 6mt group (P > 0.05). The concentration of 3-octanone dimer was significantly lower than that in the control group, but significantly higher than that in the diced group and other magnetic field groups (P < 0.05). It can be seen that the 2mt static magnetic field is superior to other magnetic field intensities in improving the aroma of fresh-cut shiitake mushrooms.

[0047] Table 2 Effects of different magnetic field intensities on characteristic odor substances of fresh-cut shiitake mushrooms

[0048]

[0049]

Claims

1. A method for increasing 3-octanone, a key aroma component of shiitake mushrooms, based on a static magnetic field, characterized in that: The following steps are involved: 1) Select the mushrooms that are intact, fresh, and free of mechanical damage; 2) Cut off the stalk of the flower mushroom, cut the flower mushroom fresh, and control the static magnetic field intensity to 2mt for 1h; 3) HS-GC-IMS and PCA analysis were performed to obtain the main aroma components of flower mushrooms and screen the key aroma components; the HS-GC-IMS analysis specifically included the following steps: the fresh-cut flower mushrooms were transferred to a headspace bottle at a dosage ratio of 1 g: 4 mL, incubated at 55°C for 15 min under an oscillating heating mode, the headspace gas was automatically injected into the GC, and separated by a 60°C MXT-5 column; the volatiles were ionized in the IMS ion chamber and driven to the migration tube for separation at 45°C by a nitrogen flow; the total analysis time was 20 min; The main aroma components of flower mushrooms include 3-octanone, 2-butanone, 2-methylbutanal and ethyl propionate.

2. The method for increasing 3-octanone, a key aroma component of shiitake mushrooms, based on a static magnetic field according to claim 1, is characterized in that: In step 2), the mushrooms are diced into small pieces; the size of the diced mushrooms is 2 to 8 mm. 3 .

3. The method for increasing 3-octanone, a key aroma component of shiitake mushrooms, based on a static magnetic field according to claim 2, is characterized in that: In step 2), the mushrooms are diced into small pieces; the size of the diced mushrooms is 5 mm. 3 .

4. The method for increasing 3-octanone, a key aroma component of shiitake mushrooms, based on a static magnetic field according to claim 1, is characterized in that: In step 3), PCA analysis was performed based on peak volume.

5. The method for increasing 3-octanone, a key aroma component of shiitake mushrooms, based on a static magnetic field according to claim 1, is characterized in that: In step 3), the key aroma component of shiitake mushroom is 3-octanone.

6. Use of the method according to any one of claims 1 to 5 in preserving shiitake mushrooms.

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