Composition for identifying freshness of mussels and application thereof

Abstract

The invention discloses a composition for identifying freshness of mussels and application of the composition, and belongs to the technical field of preservation of aquatic products. The invention relates to a composition for identifying freshness of mussels. The composition is prepared from the following components: camphene (camphene), 1-Penten-3-ol (1-pentene-3-ol), (E)-2-pentenal ((E)-2-pentenal), 1-penten-3-one (1-pentene-3-ketone), Methyl butyrate (methyl butyrate) and 5-Methyl furfural (5-methylfurfural). The composition can be applied to freshness detection in the production, transportation and sales processes of fresh mussels. The freshness of the mussels is identified by adopting flavor substances, so that the packaging form of the mussel transportation process is guided, and a foundation is laid for long-distance transportation of the mussels.

Description

Technical Field

[0001] The invention belongs to the technical field of aquatic product preservation, and in particular relates to a composition for identifying the freshness of mussels and an application thereof. Background Art

[0002] Mussels are a high-quality seafood product, which is widely recognized for its high protein, low fat and rich in various nutrients. Its fresh protein content can reach 20%, including 7 essential amino acids for the human body and 4 umami amino acids. The composition ratio of essential amino acids basically conforms to the FAO / WHO model. The ratio between copper (Cu), Fe and Zn in mineral elements is reasonable.

[0003] However, mussels are still in the primary processing stage, mainly sold in seafood markets and sold around the place of production. Their high protein and fat content leads to rapid product spoilage, making it impossible to transport fresh mussels over long distances, which greatly limits the development of the mussel industry. At this stage, it is urgent to establish a product quality confirmation method to guide the industrial development of fresh mussels. Summary of the invention

[0004] An object of the present invention is to provide a composition for identifying the freshness of mussels, and another object is to provide a specific application of the composition to make up for the deficiencies of the prior art.

[0005] Gas chromatography-ion mobility mass spectrometry (GC-IMS) is an analytical technique that combines the high separation capability of gas chromatography with the rapid detection capability of ion mobility spectrometry. It separates the components in a sample by gas chromatography, and then uses ion mobility mass spectrometry to quickly identify and quantify the separated components. In the food industry, GC-IMS is used to detect volatile organic compounds, residual pesticides, additives, and flavor components in food. It can provide detailed chemical fingerprints of complex mixtures in food, which is helpful for food quality control and safety assessment. At present, with the advancement of technology and the deepening of application, GC-IMS has begun to play a greater role in food traceability, authenticity identification, and new ingredient discovery, especially in the field of food safety supervision and functional food development.

[0006] To achieve the above object, the present invention is achieved through the following technical solutions:

[0007] A composition for identifying the freshness of mussels, comprising Camphene, 1-Penten-3-ol, (E)-2-pentenal, 1-penten-3-one, Methylbutanoate, and 5-Methylfurfural.

[0008] The composition for identifying the freshness of mussels can be applied to the freshness detection during the production, transportation and sales of fresh mussels.

[0009] The detection method for identifying whether fresh mussels are fresh by the composition comprises the following steps:

[0010] (1) Sampling: Set up sampling points at the four corners and the middle of the stacking space. At each point, take a number of small pieces from the top, middle and bottom layers and mix them into a sample. Each sample weighs 500g to 1500g.

[0011] (2) Sample preparation: The fresh mussel meat was frozen with liquid nitrogen and crushed by a cryo-grinder. 2 g of the crushed mussel meat sample was placed in a 20 mL headspace vial and sealed.

[0012] (3) Determination using GC-IMS;

[0013] (4) OPLS-DA analysis was performed on the composition to determine the freshness of the mussels, and the composition was: Camphene, 1-Penten-3-ol, (E)-2-pentenal, 1-penten-3-one, Methyl butanoate, and 5-Methylfurfural.

[0014] Further, in the step (3), the GC-IMS method is as follows: the chromatographic column is MXT-WAX, 15m, 0.53mmID, 1.0μmdf; the chromatographic column temperature is 60°C; the carrier gas / drift gas is N2; the IMS temperature is 45°C; in the automatic headspace injection unit, the injection volume is 0.5mL; the incubation time is 20min; the incubation temperature is 40°C; the injection needle temperature is 45°C; the incubation speed is 500rpm; the gas chromatography conditions are as follows: the E1 drift gas volume flow rate is 0-30min, 150mL / min; the E2 carrier gas volume flow rate is 0-2min, 2mL / min; 2-10min, 2-15mL / min; 10-15min, 15-50mL / min; 15-20min, 50-100mL / min; 20-30min, 100-150mL / min. The total running time is 50min. To avoid cross contamination, the syringe was automatically flushed with nitrogen for 30 seconds before each analysis and for 5 minutes after each analysis. Ketone compounds C4-C9 were used as external references to calculate the retention index (RI) of each volatile compound. The volatile components were analyzed by laboratory analysis viewer (Vocal) and NIST database and IMS database search.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention monitors the flavor substances of commercial fresh mussel products in different packaging forms to determine the "freshness" standard of fresh products. The present invention uses flavor substances to identify the freshness of mussels to guide the packaging form of the mussel transportation process, laying the foundation for long-distance transportation of mussels. GC-IMS uses gas phase separation and detection technology, combining the high separation ability of GC and the rapid response of ion mobility spectrometry (IMS). It has the advantages of no need for pretreatment and high sensitivity. It has excellent recognition ability for small molecules and low-content volatile components. It has been widely used in food flavor analysis and is of great significance to the development and upgrading of the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the fingerprint spectrum of the gas phase ion mobility chromatography analysis result of the direct refrigeration group in the embodiment.

[0018] Figure 2 It is the spectrum of OPLS-DA analysis results of the direct refrigeration group in the embodiment.

[0019] Figure 3 Heat map of typical flavor substance changes in the direct refrigeration group in the examples.

[0020] Figure 4 OPLS-DA analysis of samples from the oxygenation group on the third day.

[0021] Figure 5 Validation experiment of moisturizing, oxygenating and refrigerated group. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below in conjunction with embodiments.

[0023] Embodiment 1:

[0024] In this embodiment, 300 thick-shelled mussels with an average weight of 60 grams were collected from the sea area of ​​Lianyungang, China (Jiangsu Province, 34°21′12.49″N, 119°17′2.13″E). The mussels were washed with seawater to remove pollutants and byssus attached to the shells, and divided into a blank control group and an experimental group. The experimental group was further divided into a direct refrigeration group, an oxygenated refrigeration group, and an oxygenated moisturizing refrigeration group according to different storage methods; each group was divided into three parallel test groups (i.e., 30 mussels in each test group).

[0025] Among them, the direct refrigeration group was mussels packaged in ziplock bags; the oxygenated refrigeration group was mussels packaged in oxygenated bags; and the oxygenated moisturizing refrigeration group was mussels packaged in oxygenated bags with seawater absorbent cotton added. Thick-shelled mussels in different packaging forms were stored in a 1-4℃ refrigerator, and samples were taken on the 0th, 1st, 3rd, 5th, and 7th days of storage, and volatile compounds and physical and chemical indicators were measured.

[0026] In the direct cold storage group (LC), freshly purchased mussels were immediately transported from Lianyungang to Qingdao with ice after being untied after landing, and the whole process took 3.5h-4h, cold chain transportation. After arrival, 28-salinity seawater was used to clean the surface sediment and relax the stress state of the mussels. After cleaning, 80mm±5mm mussels were taken, 10 per bag, placed in 10-wire self-sealing bags, set unique numbers, placed in a 0-4℃ refrigerator, and sampled according to the sampling date.

[0027] Oxygenated refrigerated group (CY): Freshly purchased mussels are transported from Lianyungang to Qingdao with ice immediately after being untied after landing. The whole journey takes 3.5h-4h and is cold chain transportation. After arrival, 28-salinity seawater is used to clean the surface sediment and relax the stress state of the mussels. After cleaning, 80mm±5mm mussels are taken, 10 per bag, and placed in an oxygenated bag. The oxygen concentration in the oxygenated bag is 90%, and a unique number is set. It is placed in a 0-4℃ refrigerator for refrigeration and sampling is performed according to the sampling date.

[0028] Oxygenation and moisturizing refrigeration group (BS): Freshly purchased mussels are transported from Lianyungang to Qingdao with ice immediately after being untied after landing. The whole journey takes 3.5h-4h and is cold chain transportation. After arrival, 28-salinity seawater is used to clean the surface sediment and relax the stress state of the mussels. After cleaning, 80mm±5mm mussels are taken, 10 per bag, and placed in an oxygenation bag. A piece of absorbent cotton is added to the oxygenation bag, and the absorbent cotton contains 100mL of seawater. Oxygenation is performed until the oxygen concentration in the oxygenation bag reaches 90%, a unique number is set, and it is placed in a 0-4℃ refrigerator for refrigeration, and sampling is performed according to the sampling date.

[0029] Gas chromatography analysis of fresh mussels and three experimental mussels included the following steps:

[0030] (1) The three groups of mussel soft tissues were separated from their shells, frozen in liquid nitrogen, homogenized into powder and stored at -80°C for later use.

[0031] (2) Fresh mussel tissue (without storage treatment) was frozen with liquid nitrogen, homogenized into powder and stored at -80°C as a blank control group.

[0032] (3) Analysis was performed using gas chromatography-ion mobility spectrometry (GC-IMS): the chromatographic column was MXT-WAX, 15 m, 0.53 mm ID, 1.0 μm df; the chromatographic column temperature was 60 °C; the carrier gas / drift gas was N2; the IMS temperature was 45 °C; in the automatic headspace injection unit, the injection volume was 0.5 mL; the incubation time was 20 min; the incubation temperature was 40 °C; the injection needle temperature was 45 °C; the incubation speed was 500 rpm; the gas chromatography conditions were: E1 drift gas volume flow rate 0-30 min, 150 mL / min; E2 carrier gas volume flow rate 0-2 min, 2 mL / min; 2-10 min, 2-15 mL / min; 10-15 min, 15-50 mL / min; 15-20 min, 50-100 mL / min; 20-30 min, 100-150 mL / min; the total running time was 50 min. To avoid cross contamination, the syringe was automatically flushed with nitrogen for 30 seconds before each analysis and for 5 minutes after each analysis. Ketone compounds C4-C9 were used as external references to calculate the retention index (RI) of each volatile compound. The volatile components were analyzed by laboratory analysis viewer (Vocal) and NIST database and IMS database search.

[0033] Result analysis:

[0034] Since high concentrations of monomer ions and neutral molecules can form dimers in the drift region, a compound can generate multiple signals, and monomers and dimers of the same compound can also be generated. In this embodiment, the monomers and dimers formed are represented by the letters "M" and "D", respectively. By searching the NIST database and IMS database established by the qualitative software, a total of 72 volatile compounds were detected in mussels, of which 63 volatile compounds were qualitatively identified (Table 1), including 20 alcohols, 16 aldehydes, 11 ketones, 5 esters, 3 sulfides and 3 terpenes, and 5 other volatile compounds.

[0035] During the storage of bivalve molluscs, various flavor compounds undergo significant changes, including aldehyde and ketone compounds: These compounds usually provide a fresh marine flavor in the fresh state of bivalve molluscs. As the storage time increases, the oxidation of fats will lead to the production of aldehydes and ketones, which may enhance the flavor in the early stage, but excessive oxidation will produce unpleasant flavors such as rancid and sour smells. Alcohol compounds: Unsaturated alcohols have a lower threshold in bivalve molluscs, usually showing mushroom and metallic flavors, and contribute more to the flavor. As the storage time increases, the content of 1-penten-3-ol and other alcohol substances may increase, and changes in these substances can serve as a sign of flavor deterioration. Sulfur compounds: These compounds may promote the formation of flavor in fresh bivalve molluscs, but during storage, the increased concentration of sulfur-containing compounds may lead to unpleasant odors such as sulfur.

[0036] from Figure 1 It can be seen that compared with the blank control group, with the extension of storage time, the content of most aldehyde compounds decreased significantly on the fifth day of storage, and the content of most alcohol compounds gradually increased. These changes have an important impact on the stability and quality of shellfish flavor. By controlling storage conditions and monitoring the changes in flavor compounds, the flavor and quality of shellfish can be better maintained.

[0037] Table 1 Detection of volatile flavor compounds during storage of mussels by gas chromatography-ion mobility spectrometry (GC-IMS)

[0038]

[0039]

[0040] OPLS-DA is a supervised discriminant analysis statistical method that combines partial least squares regression (PLSR) and orthogonal signal correction (OSC). This method can remove data changes in the independent variable X that are not related to the classification variable Y, so that the classification information is mainly concentrated on one principal component, and effectively filter out noise that is not related to the classification information, making the model simple and easy to understand, and improving the model's analytical ability and effectiveness. The quality of the OPLS-DA model can be evaluated by parameters such as R2X, R2Y and Q2, where Q2 represents the predictive ability of the model. Q2>0.5 is generally considered to be an effective model, and Q2>0.9 indicates that the model is very good. The variable weight value (Variable Importance for the Projection, VIP) obtained by the OPLS-DA model is used to measure the influence and explanatory power of the expression pattern of each metabolite on the classification discrimination of the sample. Metabolites with VIP>1 are considered to have significant contributions in the model interpretation.

[0041] OPLS-DA analysis was performed on the direct cold storage group. Figure 2As shown in the figure, samples during different storage periods can be effectively distinguished, which provides good support for subsequent model construction and sample analysis. According to the standard of P < 0.05 and VIP > 1, the flavor compounds were analyzed. As shown in Table 2, 27 different aroma substances were screened out from the refrigerated group. The above 27 compounds were subjected to principal component analysis again. After the principal component analysis comprehensive score calculation (Table 3), 6 compounds with scores above 0.5, Camphene, 1-Penten-3-ol, (E)-2-pentenal, 1-penten-3-one, Methyl butanoate, and 5-Methylfurfural were selected as typical flavor compounds.

[0042] Table 2 Scores of compounds in the refrigerated group

[0043]

[0044] Table 3. Comprehensive score table of principal component analysis

[0045]

[0046] Based on the results of principal component analysis, Camphene, 1-Penten-3-ol, (E)-2-pentenal, 1-penten-3-one, Methyl butanoate, and 5-Methylfurfural were selected as typical flavor substances, including 2 aldehydes, 1 alcohol, 1 ketone, 1 ester, and 1 terpenoid. The concentration changes are shown in Table 2. Figure 3 ,Through the color changes, it can be seen that several typical ,flavor substances undergo changes to varying degrees as the storage time ,extends.

[0047] Embodiment 2:

[0048] Oxygen-filled packaged samples were selected for storage period experiments, and samples of different days were taken for freshness discrimination verification. Camphene, 1-Penten-3-ol, (E)-2-pentenal, 1-penten-3-one, Methyl butanoate, and 5-Methylfurfural were used as indicators to perform OPLS-DA analysis as in Example 1. Figure 4As shown, the freshness of the oxygenated storage sample on the third day was similar to that of the direct refrigeration group on the first day. Oxygenated storage can preserve freshness to a certain extent. This also shows that the use of the six flavor substances for OPLS-DA analysis can determine the freshness of live mussels.

[0049] Embodiment 3:

[0050] Moisturizing oxygenated packaging samples were selected for storage period experiments, and samples of different days were taken for freshness discrimination verification. Camphene, 1-Penten-3-ol, (E)-2-pentenal, 1-penten-3-one, Methyl butanoate, and 5-Methylfurfural were used as indicators to perform OPLS-DA analysis as in Example 1. Figure 5 As shown, the freshness of the samples in the moisturizing and oxygenating group on the 3rd day was similar to that of the direct refrigeration group on the 3rd day. The preservation ability of the moisturizing and oxygenating storage was better than that of the oxygenating group. It also shows that the use of the six flavor substances for OPLS-DA analysis can determine the freshness of live mussels in different storage states.

[0051] Finally, through experimental analysis, several markers closely related to the quality of mussels during the mussel preservation process were obtained: Camphene, 1-Penten-3-ol, (E)-2-pentenal, 1-penten-3-one, Methyl butanoate, and 5-Methylfurfural. The composition can be used to identify the freshness of mussels and can be used in freshness detection during the production, transportation and sales of fresh mussels.

[0052] Finally, although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A composition for identifying the freshness of mussels, characterized in that: The composition comprises camphene, 1-penten-3-ol, (E)-2-pentenal, 1-penten-3-one, methyl butyrate and 5-methylfurfural.

2. The composition for identifying the freshness of mussels according to claim 1 can be used in freshness detection during the production, transportation and sales of fresh mussels.

3. The method for detecting whether the composition of claim 1 is fresh or not, characterized in that: The following steps are involved: (1) Take fresh mussel samples; (2) Sample preparation: The meat of fresh mussel samples was taken, frozen with liquid nitrogen, and crushed with a cryo-grinder; (3) Determination using GC-IMS; (4) OPLS-DA is performed on the composition of claim 1 to analyze and determine the freshness of mussels.

4. The detection method according to claim 3, characterized in that In the step (1), sampling points are set at the four corners and the middle of the sample stacking space, and at each point, a number of small pieces are taken from the upper, middle and lower layers and mixed into a sample, each sample weighing 500 g to 1500 g.

5. The detection method according to claim 3, characterized in that: In the step (2), 2 g of the crushed mussel meat sample was placed in a 20 mL headspace bottle and sealed.

6. The detection method according to claim 3, characterized in that: The GC-IMS method in step (3) is as follows: the chromatographic column is MXT-WAX, 15m, 0.53mmID, 1.0μm df; the chromatographic column temperature is 60°C; the carrier gas / drift gas is N2; the IMS temperature is 45°C; the injection volume is 0.5mL; the incubation time is 20min; the incubation temperature is 40°C; the injection needle temperature is 45°C; the incubation speed is 500rpm; the gas chromatography conditions are as follows: the E1 drift gas volume flow rate is 0~30min, 150mL / min; the E2 carrier gas volume flow rate is 0~2min, 2mL / min; 2~10min, 2~15mL / min; 10~15min, 15~50mL / min; 15~20min, 50~100mL / min; 20~30min, 100~150mL / min, and the total running time is 50min.

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