De-odoring cooked mutton and de-odoring treatment process

Abstract

The invention provides a de-muttony cooked mutton and a de-muttony treatment process, the de-muttony treatment process of the cooked mutton comprises mutton pretreatment, soaking and rinsing treatment, boiling treatment and freezing and unfreezing treatment, and the cooked mutton blocks rinsed by soaking liquid and boiled by boiling liquid have the advantages that the mutton blocks can be frozen and unfrozen; a treatment mode of combining an ultra-fast freezing mode and a 4 DEG C refrigerator slow unfreezing mode is selected, so that the mutton smell of the cured mutton is reduced to the maximum extent. Meanwhile, the optimal de-odoring process of the cured mutton is determined by research as follows: the pH value of a soaking solution is 8.79, the pH value of a cooking solution is 8.49, and the soaking time is 7.8 hours. The concentrations of five key mutton smell substances before and after freezing and thawing of the cooked mutton prepared by the optimal mutton smell removal process are reduced compared with those of the original process, the mutton smell and fat taste are both lower than those of the original process, the meat flavor and nut taste are also remarkably improved, and the overall flavor of the cooked mutton is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of meat product processing, and particularly relates to deodorized cooked mutton and a deodorization treatment process. Background Art

[0002] Cooked mutton is a high-quality meat product with high protein, low fat and low cholesterol. With the improvement of people's living standards, consumers' requirements for cooked mutton are not limited to the basic nutritional value, but also have higher requirements for flavor in order to obtain a better sensory experience. At the same time, with the acceleration of the pace of social life, in recent years, quick-frozen cooked mutton convenience foods have adapted to the trend of de-chefing in the catering industry due to their advantages such as nutrition, deliciousness, simplicity and convenience, and consumer demand has continued to increase. Quick-frozen cooked mutton foods are deeply loved by consumers, but many consumers have also responded that the mutton smell of quick-frozen cooked mutton convenience foods is stronger than that of mutton foods cooked at home and in restaurants. Some consumers find it difficult to accept this, which is also the main reason why the consumption of quick-frozen cooked mutton convenience foods is lower than that of other quick-frozen meat and poultry convenience foods.

[0003] At present, the existing research on the process optimization of cooked mutton is mostly focused on using food and medicine methods to mask the mutton smell, such as adding radish, chestnut, onion, ginger, garlic, as well as cloves, cardamom and other medicinal materials when cooking mutton. However, this method can only temporarily mask the mutton smell, and the mutton smell will reappear after freezing and thawing.

[0004] Therefore, how to optimize the process conditions for removing the odor of cooked mutton and effectively reduce the content of odor substances in cooked mutton is a problem that needs to be solved urgently. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a deodorized cooked mutton and a deodorization treatment process. Taking cooked mutton as the object, the key odor substances of cooked mutton are clarified, the influence of freeze-thaw conditions on the key odor substances of cooked mutton is analyzed, the deodorization process conditions of cooked mutton are optimized, and the odor substance content of cooked mutton is effectively reduced.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A first aspect of the present invention provides a process for removing the odor of cooked mutton, comprising the following steps:

[0008] A process for removing the odor of cooked mutton comprises the following steps:

[0009] Step 1, lamb pretreatment:

[0010] Select the muscle tissue from the hind leg of the lamb and cut it into chunks for later use;

[0011] Step 2, soak and rinse:

[0012] Place the mutton chunks in a soaking solution with a pH value of 8 to 9 for 7 to 8 hours, changing the soaking solution every 10 to 20 minutes;

[0013] Step 3, cooking:

[0014] Place the soaked mutton chunks in a cooking liquid with a pH value of 8 to 9, cook over high heat for 15 to 25 minutes, then turn to low heat and continue cooking for 40 to 60 minutes, then remove and cool naturally to room temperature;

[0015] Step 4, freezing and thawing:

[0016] The cooked and matured mutton chunks are frozen in an ultra-fast manner and placed in a -20°C freezer; before consumption, the frozen matured mutton is taken out and placed in a 4°C refrigerator for slow thawing.

[0017] Furthermore, in step 2, the soaking liquid is food grade sodium hydroxide or sodium carbonate solution, with a pH value of 8.79 and a soaking time of 7.8 hours.

[0018] Furthermore, in step 3, the cooking liquid is a food grade sodium hydroxide or sodium carbonate solution with a pH value of 8.49.

[0019] Furthermore, in step 4, the ultra-fast freezing method is liquid nitrogen freezing.

[0020] A second aspect of the present invention provides a deodorized cooked mutton, wherein the cooked mutton is prepared by the above-mentioned deodorization treatment process.

[0021] Furthermore, the flavor substances providing the mutton with a strong smell include caproic acid, heptanoic acid, caprylic acid, 4-methyloctanoic acid, and capric acid, and the content ranges of the flavor substances are respectively:

[0022] 225.23±0.42~252.63±2.2μg / kg, 129.95±0.18~153.6±1.98μg / kg,

[0023] 526.53±0.15~541.56±0.53μg / kg, 29.86±0.45~33.41±0.6μg / kg and 150.44±0.63~165.24±1.1μg / kg.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention uses headspace solid phase microextraction-gas chromatography-mass spectrometry combined with olfaction to identify the key mutton smell substances in cooked mutton for the first time. A total of 36 aroma active substances were found, of which 5 substances contributed greatly to the overall mutton smell of cooked mutton, namely hexanoic acid, heptanoic acid, octanoic acid, 4-methyloctanoic acid, and decanoic acid. The aroma activity values ​​(OAV values) of the 5 mutton smell substances were analyzed and calculated, namely 4-methyloctanoic acid (OAV=2.67), decanoic acid (OAV=2.26), heptanoic acid (OAV=1.58), hexanoic acid (OAV=1.49) and octanoic acid (OAV=1.37), among which 4-methyloctanoic acid plays a leading role in the overall mutton smell of cooked mutton.

[0026] 2. By exploring the influence of freeze-thaw conditions (freezing time, freezing rate, thawing method) on the key mutton smell substances in mutton, it was determined that the freezing rate had the greatest impact on the mutton smell (P<0.05, Beta=0.844), the key mutton smell substances in slow-frozen cooked mutton had the highest content, the key mutton smell substances in fast-frozen cooked mutton had the second highest content, and the key mutton smell substances in ultra-fast frozen cooked mutton had the lowest content. The thawing method also had a slight effect on the mutton smell (P<0.05, Beta=0.215), among which thawing at 4°C had the least effect on the mutton smell, and thawing at room temperature had a slightly greater effect on the mutton smell. Therefore, a treatment method combining ultra-fast freezing and slow thawing in a 4°C refrigerator was selected to minimize the mutton smell of cooked mutton.

[0027] 3. The present invention optimizes the deodorization process of cooked mutton and reduces the content of key odor substances. The optimal deodorization process is: pH of the soaking liquid = 8.79, pH of the cooking liquid = 8.49, and the soaking time is 7.8h. The concentrations of the five key odor substances in the cooked mutton prepared by the optimal deodorization process before and after freeze-thawing are lower than those of the original process, and the mutton smell and fat smell are lower than those of the original process. The meaty aroma and nutty flavor are also significantly improved, and the overall flavor of the cooked mutton is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention.

[0029] Figure 1 The effect of freezing time on the content of odor substances is shown;

[0030] Figure 2 The freezing curves under different freezing modes are shown;

[0031] Figure 3 The effect of freezing rate on the content of odor substances is shown;

[0032] Figure 4 The effect of thawing method on the content of odor substances is shown;

[0033] Figure 5 The effect of soaking liquid pH on the content of odor substances is shown;

[0034] Figure 6 The effect of cooking liquid pH on the content of odor substances is shown;

[0035] Figure 7 The effect of soaking time on the content of odor substances is shown;

[0036] Figure 8 This is the sensory radar chart of the smell of cooked mutton treated with different pH values ​​of soaking liquids;

[0037] Fig. 9 This is the sensory radar chart of the smell of cooked mutton treated with different cooking liquid pH;

[0038] Fig.10 This is the sensory radar chart of the smell of cooked mutton treated with different soaking time;

[0039] Fig.11 This is the odor sensory radar chart of cooked mutton before and after optimization. DETAILED DESCRIPTION

[0040] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0041] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0042] Some detection methods involved in the embodiments of the present invention include:

[0043] Headspace solid phase microextraction (HS-SPME):

[0044] SPME extraction conditions established:

[0045] Extraction fiber treatment conditions: First, the SPME extraction fiber (50 / 30 μm DVB / CAR / PDMS) was aged for 30 min at an injection port temperature of 270 °C to remove contaminants and residues on the fiber surface. Subsequently, the volatile flavor components in the sample were adsorbed in a heater and desorbed at an injection port temperature of 250 °C for 3 min.

[0046] (1) Extraction temperature: Accurately weigh 3.00 g of cooked mutton into a 15 mL sample bottle, add 10 μL of 4-methyl-2-pentanol (100 mg / L) as an internal standard, quickly tighten the bottle cap and seal it. Place the sample bottle on the SPME-GC-MS autosampler for analysis. The sample extraction temperatures were set to 45°C, 55°C, 65°C, 75°C, and 85°C, respectively, with a 15 min equilibration time and a 30 min extraction time.

[0047] (2) Extraction time: Accurately weigh 3.00 g of cooked mutton into a 15 mL sample bottle, add 10 μL of 4-methyl-2-pentanol (100 mg / L) as an internal standard, quickly tighten the bottle cap and seal it. Place the sample bottle on the SPME-GC-MS autosampler for analysis. The sample extraction temperature is based on the optimal extraction temperature determined in (1), the equilibrium time is 15 min, and the extraction time is set to 20 min, 30 min, 40 min, and 50 min, respectively.

[0048] (3) Sample amount: Accurately weigh different grams of cooked mutton, namely 1.00g, 1.50g, 2.00g,

[0049] 2.50g, 3.00g, 3.50g, and 4.00g of cooked mutton were placed in a 15mL sample bottle, and 10μL of 4-methyl-2-pentanol (100mg / L) was added as an internal standard. The bottle cap was quickly tightened and sealed. The sample bottle was placed on the SPME-GC-MS autosampler for analysis. The sample extraction temperature was based on the optimal extraction temperature determined in (1), the equilibrium time was 15min, and the sample extraction time was based on the optimal extraction time determined in (2).

[0050] GC-MS detection conditions:

[0051] Chromatographic conditions: chromatographic column (DB-WAX 30m×250μm×0.25μm); film thickness 0.20mm, carrier gas is high-purity He, flow rate 1.6mL / min. Temperature program: 40℃ for 3min, increase to 230℃ at 5℃ / min, maintain for 2min, total operation time 43min. Inlet temperature 250℃.

[0052] Mass spectrometry conditions: electron impact (EI) ion source, electron energy 70 eV; ion source temperature 230°C; mass scan range 35-550 m / z, full scan, solvent delay 3 min.

[0053] Qualitative and quantitative analysis of volatile flavor substances: After the volatile substances are separated by chromatographic columns, the compounds are compared and identified by the Nist17 data library, and the content of each volatile substance in cooked mutton is calculated based on the peak area of ​​4-methyl-2-pentanol with known mass concentration. The calculation of the internal standard quantitative of volatile compounds is shown in the formula:

[0054]

[0055] Wherein, M(x) is the relative content of the compound x to be tested, in μg / kg; A(x) is the peak area of ​​the volatile compound x to be tested; A(i) is the peak area of ​​the internal standard compound; C(i) is the mass concentration of the internal standard compound, in μg / mL; a is the volume of the added standard, in μL; b is the mass of the added sample, in g; 1000 in the numerator represents 1 kg, and 1000 in the denominator represents 1000 μL.

[0056] Analysis of aroma components in cooked mutton:

[0057] Smell operation: Smell operation needs to be performed by experienced researchers who should undergo special olfactory training to ensure accurate description of odor attributes. During the olfactory process, researchers need to pay close attention to the peak time of the chromatographic program in order to capture and record the information of volatile flavor substances in a timely manner. The smell under each condition should be repeated multiple times to improve the reliability and consistency of the results.

[0058] Quantitative analysis of key odor substances:

[0059] Establishment of standard curve. The standard of key odorous substances determined by olfaction was dissolved in methanol and prepared into a mixed solution with a concentration of 1 mg / mL, and refrigerated for use. Before use, it was prepared into the following concentrations: 5.00 μg / mL, 10.00 μg / mL, 20.00 μg / mL, 50.00 μg / mL, 100.00 μg / mL. These diluted solutions were analyzed by gas chromatography-mass spectrometry, and the standard curve was drawn by measuring the response value of the substance at each concentration.

[0060] The calculation method of aroma activity value (OAV value) is as follows:

[0061]

[0062] Wherein, C(x) is the concentration of the aroma substance x to be measured; T(x) is the threshold value of the aroma substance x to be measured; OAV(x) is the aroma activity value of the aroma substance x to be measured.

[0063] Materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources. Lamb leg meat (one-year-old small-tailed Han sheep) was purchased from Inner Mongolia Grassland Xinhe Food Co., Ltd. Muscle tissue from the hind leg of lamb meat was selected and cut into small pieces of 3 cm×3 cm×3 cm.

[0064] The present invention is described in detail below through embodiments in conjunction with the accompanying drawings, but this does not limit the present invention and is only used as an example.

[0065] Example 1 - Analysis of key odor substances in cooked mutton

[0066] The volatile flavor substances produced by cooked mutton during the cooking process are very complex and are mainly produced through lipid oxidation and Maillard reaction. This example uses mass spectrometry analysis (MS), spectral library retrieval, retention time (RT value) comparison and other methods to conduct qualitative and relative quantitative analysis of the volatile flavor substances in cooked mutton. The effect of extraction temperature on various volatile flavor substances in cooked mutton is discussed.

[0067] The muscle tissue from the hind leg of lamb was selected and cut into small pieces of 3cm×3cm×3cm. The pieces were then boiled in water over high heat for 20min and then boiled over low heat for 50min. The cooked lamb was then removed from the water and naturally cooled to room temperature. The flavor of the samples was then tested.

[0068] The results showed that 36 aroma components were identified in the cooked mutton before freeze-thaw, including 5 alcohols, namely 3-methyl-2-butanol, (Z)-3-nonen-1-ol, 1-octen-3-ol, 2,3-butanediol and benzyl alcohol, which have fruity, vegetable and mushroom flavors. The flavor threshold of alcohol substances is relatively high, and their aroma has almost no contribution to the overall mutton smell of cooked mutton. There are 9 kinds of aldehydes, namely hexanal, heptanal, octanal, (E)-2-octenal, 3-hydroxy-4-methoxybenzaldehyde, phenylglyoxal, (E)-2-nonenal, undecenal, and (E,Z)-2,4-decadienal. They are highly volatile. Straight-chain aldehydes are formed by oxidation of fatty acids, while branched-chain aldehydes are produced by Streker degradation. They have grassy, ​​nutty, fat, vanilla, rose, and fruity flavors. Aldehydes play a leading role in the overall aroma of cooked mutton, which is consistent with the research results of the characteristic aroma components of Ningxia beach mutton. There are 9 kinds of acids, namely pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, 4-methyloctanoic acid, nonanoic acid, decanoic acid, undecanoic acid, and dodecanoic acid. Acidic substances are generally produced by small molecular fatty acids formed by fat hydrolysis or lipid oxidation. They are important components for the formation of meat flavor characteristics, with mutton smell, fatty acid rancidity, rancidity, sweat, weak sourness, cheese flavor, etc., and play a major role in the overall mutton smell of cooked mutton. There are 5 kinds of sulfur-containing compounds, namely sulfur dioxide, methanesulfonyl chloride, ethylenesulfonyl chloride, dimethyl trisulfide, and 2-acetylthiazole; there are 3 kinds of hydrocarbons, namely 3-methyl-3-undecene, 1,1-dimethylcyclopentane, and 2-chloro-2-nitropropane. Hydrocarbon compounds are also important components of the volatile components of mutton aroma. They are mainly produced by bond homolysis during lipid thermal degradation or long-chain fatty acid self-oxidation. Although there are many types of hydrocarbon compounds in the aroma of mutton, due to their high flavor threshold, their contribution to the overall mutton smell of cooked mutton is relatively small, which means that although hydrocarbon compounds exist in mutton, they do not dominate the mutton smell characteristics. One furan, 2-pentylfuran, as a product of linoleic acid auto-oxidation, frequently appears in the identification of mutton volatile components, indicating that it may be one of the important aroma components in fat-containing foods and may have a potential role in promoting the overall mutton smell of cooked mutton.

[0069] Not all the volatile flavor substances identified contribute to the overall flavor of cooked mutton. The aroma properties of the aroma components screened and identified by GC-O method include fruity, vegetable, mushroom, creamy, grassy, ​​nutty, fat, meaty, and smelly. There are five key mutton odor substances, namely Hexanoic acid, heptanoic acid, octanoic acid, 4-methyloctanoic acid, decanoic acid .

[0070] Example 2 - Effect of freeze-thaw process on mutton odor substances in cooked mutton

[0071] In order to explore the effects of different freeze-thaw processes on the mutton odor substances of cooked mutton, the cooked mutton cooled in Example 1 was taken, and all samples were divided into three groups, vacuum packed and frozen at different temperatures, respectively placed in a -20°C freezer, a -80°C refrigerator and liquid nitrogen for freezing, and all samples were placed in a -20°C freezer for storage after freezing. The flavor substances of the samples in each group after freeze-thaw process were measured (the method was the same as in Example 1).

[0072] The standard curves of five key odor substances were established, and the key odor substances in cooked mutton before and after freezing and thawing were quantitatively analyzed. The results are shown in Table 1. The contents of key odor substances in cooked mutton after freezing and thawing increased significantly. Among them, the contents of heptanoic acid, 4-methyloctanoic acid, decanoic acid, hexanoic acid and octanoic acid in cooked mutton after freezing and thawing increased by 73.6%, 72.51%, 61.91%, 48.75% and 16.67% respectively compared with those before freezing and thawing. The OAV values ​​of key odor substances were calculated by compound concentration and its aroma threshold value. The results are shown in Table 2. The concentrations of the five odor substances detected in cooked mutton were all greater than their aroma threshold values ​​(OAV≥1). Among them, 4-methyloctanoic acid has the highest OAV value (OAV before freezing and thawing = 2.67, OAV after freezing and thawing = 4.6), followed by decanoic acid (OAV before freezing and thawing = 2.26, OAV after freezing and thawing = 3.65), heptanoic acid (OAV before freezing and thawing = 1.58, OAV after freezing and thawing = 2.74), hexanoic acid (OAV before freezing and thawing = 1.49, OAV before freezing and thawing = 2.21), and octanoic acid (OAV before freezing and thawing = 1.37, OAV after freezing and thawing = 2.21). Although 4-methyloctanoic acid has the lowest content, its OAV value is the highest, indicating that 4-methyloctanoic acid plays a leading role in the overall mutton smell of cooked mutton.

[0073] Table 1 Quantitative analysis of key odor substances in mutton before and after freezing and thawing

[0074]

[0075] Table 2 Aroma activity values ​​of key odor substances in mutton before and after freezing and thawing

[0076]

[0077] Furthermore, this example explores the effects of freezing time, freezing rate and thawing method on the mutton odor of cooked mutton.

[0078] 1. Effect of freezing time on the mutton odor of cooked mutton

[0079] The results of the effects of freezing time on the content of key odor substances in frozen-thawed cooked mutton are as follows Figure 1 As shown. Figure 1It can be seen that with the extension of freezing time, the content of mutton smell increased slightly, but the increase was small. Compared with the cooked mutton frozen for 1 day, the content of caproic acid increased by 1.02%, the content of heptanoic acid increased by 0.94%, the content of octanoic acid increased by 1.06%, the content of 4-methyloctanoic acid increased by 2.26%, and the content of decanoic acid increased by 1.26% in the cooked mutton frozen for 60 days. The freezing time (1-60 days) had little effect on the mutton smell after freeze-thaw (P<0.05, Beta=0.169). It may be that low-temperature freezing inhibits the life activities of microorganisms. At the same time, more than 80% of the water in the cooked mutton has been converted into ice crystals. The bound water is often tightly combined with macromolecular substances such as proteins in the meat, and is not easily affected by external conditions. With the extension of freezing time, ice crystals grow, and the meat structure is seriously damaged, which may cause the mutton smell to dissolve together with the non-flowing water. Therefore, during the frozen storage period without temperature fluctuation, the effect of short-term freezing on the mutton odor of cooked mutton can be ignored, and long-term freezing will still cause a slight increase in mutton odor substances. Therefore, in actual production, it is necessary to avoid long-term freezing of cooked mutton products as much as possible.

[0080] 2. Effect of Freezing Rate on the Odor of Cooked Mutton

[0081] Figure 2 The freezing curves of cooked mutton under different freezing methods are shown. As can be seen from the figure, the freezing process is roughly divided into three stages. The first section is the range from room temperature to -1°C. This stage is mainly the initial drop in the temperature of the mutton and has not yet entered the significant freezing stage. The second section is from -1°C to -5°C. This range is called the maximum ice crystal formation zone and is the most critical stage in the freezing process. At this stage, most of the water in the mutton (about 80%) will be converted into ice crystals, which has an important impact on the tissue structure and quality of the mutton. Therefore, the study pointed out that in order to ensure the quality of frozen products, this stage should be passed as quickly as possible. Table 3 provides the freezing rate data under different freezing methods. As can be seen from the table, as the ambient temperature decreases, the freezing rate increases significantly (P<0.05). Specifically, the freezing rate of the -20°C freezing group is 0.25cm·h-1, which is a slow freezing; the freezing rate of the -80°C freezing group is 1.43cm·h-1, which is a fast freezing; and the freezing rate of the liquid nitrogen freezing group is as high as 37.5cm·h-1, which is an ultra-fast freezing. According to the freezing rate, we can classify different freezing methods. In this experiment, the -20℃ freezing group, -80℃ freezing group and liquid nitrogen freezing group are slow freezing, fast freezing and ultra-fast freezing respectively.

[0082] Table 3 Freezing rate under different freezing methods

[0083]

[0084] The results of the effects of freezing rate on key odor substances in frozen-thawed cooked mutton are as follows Figure 3 As shown. Figure 3 It can be seen that the content of key mutton smell substances in slow-frozen cooked mutton is the highest, the content of key mutton smell substances in fast-frozen cooked mutton is the second, and the content of key mutton smell substances in ultra-fast frozen cooked mutton is the lowest. The freezing rate has a greater effect on the mutton smell (P<0.05, Beta=0.844). Compared with the cooked mutton before freeze-thaw, the content of caproic acid in slow-frozen cooked mutton increased by 48.74%, the content of heptanoic acid increased by 73.61%, the content of octanoic acid increased by 16.67%, the content of 4-methyloctanoic acid increased by 72.5%, and the content of decanoic acid increased by 61.91%. Compared with the cooked mutton before freeze-thaw, the content of caproic acid in fast-frozen cooked mutton increased by 19.36%, the content of heptanoic acid increased by 32.36%, the content of octanoic acid increased by 6.42%, the content of 4-methyloctanoic acid increased by 34.48%, and the content of decanoic acid increased by 14.91%. In the ultra-fast frozen cooked mutton, the content of caproic acid increased by 4.53%, the content of heptanoic acid increased by 3.54%, the content of octanoic acid increased by 1.86%, the content of 4-methyloctanoic acid increased by only 5.11%, and the content of decanoic acid increased by 4.25%. During the freezing process, the water outside the muscle cells forms a large number of ice crystals due to the decrease in temperature. When the liquid water diffuses to the growing crystals, the ice crystals between the tissues will grow longer and larger, causing mechanical damage to the cell membrane and tissue structure in the frozen meat. The lower the freezing temperature, the smaller, more uniform and denser the ice crystals will be, causing less damage to the muscles and cells, thereby reducing the outflow of volatile flavor substances to a certain extent. This can be used to explain the fact that the content of key mutton flavor substances in the cooked mutton of the ultra-fast freezing group in this study is the lowest, followed by the rapid freezing group, and the content of key mutton flavor substances in the cooked mutton of the slow freezing group is the highest.

[0085] 3. The influence of thawing method on the mutton odor of cooked mutton

[0086] The results of the effects of thawing methods on the odor substances in frozen-thawed cooked mutton are as follows Figure 4 As shown. Figure 4It can be seen that the key mutton smell substances in the cooked mutton thawed at 4℃ group were the lowest, followed by the running water thawing group and the room temperature thawing group. The thawing method also had a slight effect on the mutton smell (P<0.05, Beta=0.215). Compared with the cooked mutton before freezing and thawing, the content of caproic acid increased by 48.74%, the content of heptanoic acid increased by 73.61%, the content of octanoic acid increased by 16.67%, the content of 4-methyloctanoic acid increased by 72.5%, and the content of decanoic acid increased by 61.91%. Compared with the cooked mutton before freezing and thawing, the content of caproic acid increased by 51.97%, the content of heptanoic acid increased by 77.08%, the content of octanoic acid increased by 17.76%, the content of 4-methyloctanoic acid increased by 77.69%, and the content of decanoic acid increased by 63.66% in the cooked mutton thawed at 4℃. In the cooked mutton thawed at room temperature, the content of caproic acid increased by 55.99%, the content of heptanoic acid increased by 84.70%, the content of octanoic acid increased by 20.77%, the content of 4-methyloctanoic acid increased by 91.04%, and the content of decanoic acid increased by 67.37%. The larger ice crystals formed during the freezing process damage the microstructure of the mutton, and the water loss increases after thawing. This will cause more volatiles to be released, causing the smell of mutton to flow out. The thawing method has a significant impact on frozen meat products. Improper thawing may cause deterioration, and thawing too quickly will aggravate the loss of juice. Among the three thawing groups in this embodiment, the temperature difference between 4°C thawing and the frozen storage temperature (-20°C) is the smallest, the ice crystal melting speed is the slowest, and the juice loss is the smallest. Therefore, the 4°C thawing group has the least effect on the smell of mutton, and the room temperature thawing group has the greatest effect on the smell of mutton.

[0087] In summary, this example determined the composition of key mutton odor substances in cooked mutton by SPME-GC-MS method and GC-O method, and analyzed the effect of freeze-thaw conditions on key mutton odor substances in cooked mutton, and obtained the following conclusions:

[0088] (1) The volatile flavor substances in cooked mutton were qualitatively and relatively quantitatively analyzed to determine the appropriate SPME extraction conditions. The aroma components in cooked mutton were analyzed by SPME, gas chromatography-mass spectrometry and olfaction. The key mutton odor substances in cooked mutton were identified as hexanoic acid, heptanoic acid, octanoic acid, 4-methyloctanoic acid and decanoic acid. The concentrations of these five key mutton odor substances in cooked mutton were quantitatively analyzed and their OAV values ​​were calculated. The detected concentrations of the five key mutton odor substances were all greater than their aroma threshold values ​​(OAV≥1). Among them, 4-methyloctanoic acid had the largest OAV value and played a leading role in the overall mutton odor of cooked mutton.

[0089] (2) The effects of freeze-thaw on key mutton odor substances in cooked mutton were analyzed. The contents of key mutton odor substances in cooked mutton increased significantly after freeze-thaw. Under different freeze-thaw conditions, the freezing time (1-60 days) had little effect on the mutton odor after freeze-thaw (P<0.05, Beta=0.169). The freezing rate had the greatest effect on the odor (P<0.05, Beta=0.844). The content of key mutton odor substances in cooked mutton frozen slowly was the highest, followed by the content of key mutton odor substances in cooked mutton frozen quickly, and the content of key mutton odor substances in cooked mutton frozen ultra-fast was the lowest. The thawing method also had a slight effect on the odor (P<0.05, Beta=0.215). Among them, thawing at 4°C had the least effect on the odor, and thawing at room temperature had a slightly greater effect on the odor.

[0090] Example 3

[0091] This embodiment provides a process for removing the odor of cooked mutton, comprising the following steps:

[0092] Step 1, lamb pretreatment:

[0093] The muscle tissue of the lamb hind leg was selected and cut into small pieces of 3 cm×3 cm×3 cm.

[0094] Step 2, soak and rinse:

[0095] Prepare soaking solution, which can be food grade sodium hydroxide or sodium carbonate solution.

[0096] Place the mutton chunks in a soaking solution with a pH value of 8-9, soak for 7-8 hours, and replace the soaking solution every 10-20 minutes.

[0097] Step 3, cooking:

[0098] Prepare cooking liquid, which can be food grade sodium hydroxide or sodium carbonate solution.

[0099] The soaked mutton chunks are placed in a cooking liquid having a pH value of 8-9, and cooked over high heat for 15-25 minutes, then reduced to low heat and continued to cook for 40-60 minutes before being taken out and naturally cooled to room temperature to obtain deodorized mature mutton.

[0100] Step 4, freezing and thawing:

[0101] The cooked and matured mutton chunks are frozen in an ultra-fast manner and placed in a -20°C freezer; before consumption, the frozen matured mutton is taken out and placed in a 4°C refrigerator for slow thawing.

[0102] In this example, the contents and aroma activity values ​​of five key mutton smell substances are used as evaluation indicators of the mutton smell of cooked mutton prepared by different mutton removal processes, and the content change of 4-methyloctanoic acid in cooked mutton under different conditions is focused on.

[0103] Firstly, the effects of different soaking liquid pH, cooking liquid pH and soaking time on the content of key mutton odor substances in cooked mutton were studied. Based on the results of single factor experiments, response surface experiments were carried out to determine the optimal odor removal process.

[0104] 1. Effect of soaking solution pH on the content of key odor substances

[0105] The effect of soaking liquid pH on the content of key mutton smell substances in cooked mutton was analyzed: the same soaking time (15 minutes per cycle, a total of 4 hours) and cooking liquid pH (6.5) were maintained, and different soaking liquid pHs (6.5, 7, 7.5, 8, 8.5, 9) were used to soak, rinse and cook the mutton. The content of key mutton smell substances in the corresponding cooked mutton was determined.

[0106] The results are as follows Figure 5 As shown. The experiment found that the content of key mutton smell substances in cooked mutton decreased with the increase of soaking liquid pH and then tended to be stable. The content of key mutton smell substances in cooked mutton treated with soaking liquid pH (8.5) and soaking liquid pH (9) was basically the same. This is because the alkaline soaking liquid, on the one hand, elutes the fatty acids that cause the mutton smell, and on the other hand, neutralizes the fatty acids in the mutton, thereby reducing the content of key mutton smell fatty acids in cooked mutton. Since the mutton blocks have a certain thickness, it affects the diffusion of mutton smell substances into water and also affects the penetration of water into mutton. This may be the reason why the content of key mutton smell substances decreases with the increase of soaking liquid pH and then tends to be stable. When the pH of the soaking solution was 8.5, the reduction rate of the key mutton smell substances in cooked mutton was the most significant, among which the reduction rate of heptanoic acid reached 39.99%, followed by 4-methyloctanoic acid, which reached 25.36%, hexanoic acid, which reached 24.81%, decanoic acid, which reached 18.27%, octanoic acid, which reached 13.59%, and the reduction rate of the key mutton smell substances reached 21.04%. Among them, although the content of 4-methyloctanoic acid was the lowest, its OAV value was the highest, and it contributed the most to the overall mutton smell of cooked mutton. The soaking solution treatment with a pH of 8.5 can significantly reduce the content of 4-methyloctanoic acid, thereby reducing the mutton smell of cooked mutton.

[0107] 2. Effect of cooking liquid pH on the content of key mutton odor substances

[0108] The effect of cooking liquid pH on the content of key mutton odor substances in cooked mutton was analyzed: the same soaking liquid pH (6.5) and soaking time (15 minutes per cycle, a total of 4 hours) were maintained, and different cooking liquids (6.5, 7, 7.5, 8, 8.5, 9) were used to soak, rinse and cook the mutton. The content of key mutton odor substances in the corresponding cooked mutton was determined.

[0109] The results are as follows Figure 6 As shown. The experiment found that the content of key mutton smell substances in cooked mutton decreased with the increase of cooking liquid pH and then tended to be stable. The content of key mutton smell substances in cooked mutton treated with cooking liquid pH (8.5) and cooking liquid pH (9) was basically the same. This is because during the cooking stage, under the action of high temperature, the alkaline cooking liquid makes the fatty acids in the mutton more effectively dissolved and saponified, thereby reducing the content of key mutton smell substances in cooked mutton. When the cooking liquid pH is 8.5, the reduction rate of the key mutton smell substances in cooked mutton is the most significant, among which the reduction rate of heptanoic acid reaches 47.11%, followed by 4-methyloctanoic acid, with a reduction rate of 33.79%, the reduction rate of decanoic acid reaches 23.38%, the reduction rate of hexanoic acid reaches 26.85%, the reduction rate of octanoic acid reaches 20.26%, and the reduction rate of the key mutton smell substances and reaches 26.51%. When the pH value of the cooking liquid is 8.5, the effect of reducing the mutton odor of cooked mutton is the best, and the effect of reducing the content of mutton odor substances is much better than that when the pH value of the soaking liquid is 8.5, which is more conducive to the removal of the mutton odor.

[0110] 3. Effect of soaking time on the content of key odor substances

[0111] The effect of soaking time on the content of key mutton smell substances in cooked mutton was analyzed: the pH of the soaking liquid (6.5) and the pH of the cooking liquid (6.5) were kept the same, the soaking time was 15 minutes per cycle, and the total time was 4h, 5h, 6h, 7h, and 8h respectively, and the mutton was soaked, rinsed, and cooked. The content of key mutton smell substances in the corresponding cooked mutton was determined.

[0112] The results are as follows Figure 7As shown. The experimental results show that with the extension of soaking time, the content of key odor substances in cooked mutton shows a trend of first decreasing and then stabilizing. The content of key odor substances in cooked mutton treated with soaking time (7h) and soaking time (8h) is basically the same. This phenomenon can be explained by the effect of concentration difference on the elution of odor fatty acids and the penetration of soaking solution. At the same temperature, concentration difference is a key factor in determining the diffusion rate of substances. When the mutton begins to soak, there is a large concentration difference between the components in the soaking solution and the odor fatty acids in the mutton. This concentration difference drives the odor fatty acids to elute from the mutton and promotes other components in the soaking solution to penetrate into the mutton. Therefore, in the initial stage of soaking, the elution rate of odor fatty acids and the penetration rate of the soaking solution are relatively fast, resulting in a rapid decrease in the content of key odor substances in mutton. However, as time goes by, the odor fatty acids in the mutton are gradually eluted, and the relevant components in the soaking solution gradually reach equilibrium. This means that the concentration difference gradually decreases and the diffusion driving force weakens. Therefore, the elution rate of mutton fatty acids and the penetration rate of the soaking solution gradually decreased until a dynamic equilibrium state was reached. At this stage, the content of key mutton odor substances in mutton no longer changed significantly, showing a trend of stabilization. When the soaking time was 7h, the reduction rate was the most significant, among which the reduction rate of heptanoic acid reached 31.83%, followed by 4-methyloctanoic acid, with a reduction rate of 22.13%, decanoic acid, 18.27%, hexanoic acid, 13.69%, and octanoic acid. The reduction rate of the content and the reduction rate of key mutton odor substances reached 15.07%. If the soaking time is extended blindly, the sensory quality of cooked mutton will be reduced. In this experiment, the effect of reducing the mutton odor of cooked mutton was best when the soaking time was 7h.

[0113] 4. Flavor sensory evaluation and analysis of cooked mutton

[0114] Quantitative descriptive analysis (QDA) was used to evaluate the artificial flavor of cooked mutton samples. The sensory evaluation panelists were required to undergo preliminary screening, that is, they had normal sensory functions and certain sensory sensitivity, and also had good expression skills. The panel consisted of 10 trained personnel with sensory evaluation experience, including 6 women and 4 men. The evaluation was conducted at room temperature. Before the sensory evaluation of cooked mutton samples, the sensory evaluators were first trained to give them a preliminary understanding of the flavor characteristics and intensity of cooked mutton, and then the characteristic terms describing the flavor of cooked mutton were determined. The sensory evaluation panel discussed and obtained the vocabulary that habitually describes the flavor of cooked mutton. The given descriptive words were counted, and the five most frequent words were selected as quantitative descriptors, namely meat aroma, nutty flavor, grassy flavor, fat flavor and mutton flavor. Finally, using these five descriptors and the overall flavor as indicators, the flavor of the cooked mutton was scored on an 11-point scale (1-2, very weak; 3-4, weak; 5-6, medium; 7-8, strong; 9-11, very strong).

[0115] like Figure 8-Figure 10 As shown, Figure 8 :Different soaking solution pH treatment, Fig. 9 : Different cooking liquid pH treatment), Fig.10 :Different soaking time treatments represent the odor analysis results of cooked mutton after different deodorization processes. The results of flavor sensory evaluation show that meaty aroma, nutty flavor, grassy flavor, fat flavor and mutton are the main odors of cooked mutton. When the pH of the soaking solution is 6.5, the soaking time is 4h, and the pH of the cooking solution is 6.5, the mutton mutton has the strongest mutton mutton, fat flavor and grassy flavor, and the weakest meaty aroma and nutty flavor. With the increase of the pH of the soaking solution, the soaking time and the pH of the cooking solution, the mutton mutton mutton, fat flavor and grassy flavor decrease, and the meaty aroma and nutty flavor become stronger. It may be because the mutton mutton has too heavy mutton mutton, fat flavor and grassy flavor, which mask the meaty aroma and nutty flavor of the cooked mutton. After deodorization treatment, the content of key mutton mutton mutton mutton is reduced, making the meaty aroma and nutty flavor of the cooked mutton more prominent in the flavor sensory sense. The results showed that the flavor sensory analysis results of cooked mutton were consistent with the effects of different soaking liquid pH, cooking liquid pH and soaking time on the content of key mutton odor substances.

[0116] In order to optimize the best conditions for the deodorization process, based on the results of single-factor experiments, the response surface methodology was used to study the effects of soaking liquid pH, cooking liquid pH, and soaking time on the content of key odor substances in cooked mutton. The optimal deodorization process parameters were finally determined: Soaking liquid pH = 8.79, cooking liquid pH = 8.49, soaking time is 7.8h .

[0117] Comparative Example:

[0118] This comparative example provides a process for removing the odor of cooked mutton. The process steps are basically the same as those in the above-mentioned Example 3, except that: the pH value of the soaking liquid is 6.5, and the soaking time is 4 hours; the pH value of the cooking liquid is 6.5.

[0119] The contents of five key odor substances in the cooked mutton obtained by the original process and the optimal odor removal process (steps 1-3) of Example 3 were compared, and the results are shown in Table 4. The content of 4-methyloctanoic acid in the cooked mutton obtained by the optimal odor removal process was reduced by 43.51% compared with the original process, the content of decanoic acid was reduced by 48.69% compared with the original process, the content of heptanoic acid was reduced by 17.59% compared with the original process, the content of caproic acid was reduced by 24.34% compared with the original process, and the content of octanoic acid was reduced by 22.9% compared with the original process.

[0120] Table 4 Comparison of the contents of odor substances in cooked mutton prepared by the original process and the optimal deodorization process

[0121]

[0122] Furthermore, the cooked mutton obtained by the original process and the optimal deodorization process (steps 1-3) was subjected to freeze-thaw treatment (freezing at -20°C and thawing at 4°C), and the contents of five key odor substances in the cooked mutton after freeze-thaw were analyzed. The results are shown in Table 5. After freeze-thawing of the cooked mutton obtained by the optimal deodorization process, the contents of the five key odor substances were greatly reduced compared with those of the cooked mutton obtained by the original process. The content of 4-methyloctanoic acid was reduced by 63.67%, the content of decanoic acid was reduced by 65.19%, the content of heptanoic acid was reduced by 43.88%, the content of caproic acid was reduced by 42.95%, and the content of octanoic acid was reduced by 23.03%. It shows that the optimal deodorization process can effectively reduce the content of key odor substances in cooked mutton before and after freeze-thawing, and effectively improve the quality of cooked mutton before and after freeze-thawing. It provides technical support for the development of the quick-frozen cooked mutton convenience food industry.

[0123] Table 5 Comparison of the contents of odor substances in cooked mutton after freeze-thawing prepared by the original process and the optimal deodorization process

[0124]

[0125] The flavor radar chart of cooked mutton samples drawn based on the flavor sensory evaluation results is as follows: Fig.11 The use of the flavor radar chart to describe the flavor sensory characteristics of the product can intuitively compare the differences between the original process and the optimal process, that is, the effects of the deodorization process and freeze-thaw on the flavor characteristics of cooked mutton. Fig.11It can be seen that the scores of mutton smell and fat taste of cooked mutton obtained by the optimal deodorization process are lower than those of the original process, which may be due to the fact that the contents of the five key mutton smell substances in the cooked mutton obtained by the optimal deodorization process are significantly reduced, and the meat aroma and nutty flavor masked by the mutton smell and fat taste are also significantly improved. In summary, the overall flavor score of cooked mutton obtained by the optimal deodorization process is higher than that of the original process. Freeze-thaw will affect the mutton smell substances in cooked mutton. The content of key mutton smell substances in cooked mutton after freeze-thaw increases significantly, resulting in the flavor of cooked mutton after freeze-thaw being inferior to that before freeze-thaw. However, the scores of mutton smell and fat taste of cooked mutton obtained by the optimal deodorization process after freeze-thaw are much lower than those of cooked mutton obtained by the original process after freeze-thaw. At the same time, the meat aroma and nutty flavor are also much higher than those of cooked mutton obtained by the original process after freeze-thaw. The results showed that the flavor sensory analysis results of cooked mutton before and after freeze-thawing obtained by the original process and the optimal deodorization process were the same as their effects on the content of key odor substances.

[0126] In summary, this comparative example first explored the effects of soaking liquid pH, cooking liquid pH and soaking time on the content of key mutton odor substances in cooked mutton, and conducted a response surface optimization experiment based on the single factor experiment. The following conclusions were obtained:

[0127] (1) The optimal deodorization process obtained by optimization significantly reduced the content of key odor substances in cooked mutton. The optimal deodorization process was as follows: pH of soaking liquid: 8.79, pH of cooking liquid: 8.49, soaking time: 7.8h; the content of 4-methyloctanoic acid in cooked mutton prepared after the optimization of deodorization process was reduced by 43.51%, the content of decanoic acid was reduced by 48.69%, the content of heptanoic acid was reduced by 17.59%, the content of hexanoic acid was reduced by 24.34%, and the content of octanoic acid was reduced by 22.9%. The content of 4-methyloctanoic acid in cooked mutton measured under this treatment was 29.86μg / kg, which was 43.51% lower than that of the original process. The difference with the model value was 0.17%, indicating that the prediction conditions were reliable.

[0128] (2) Improved the overall flavor quality of cooked mutton. The concentrations of key odor substances in cooked mutton obtained by the optimal deodorization process before and after freeze-thawing were lower than those obtained by the original process, and the meaty aroma and nutty flavor were also significantly improved. The results showed that the optimal deodorization process can effectively reduce the content of key odor substances in cooked mutton before and after freeze-thawing, and effectively improve the overall flavor quality of cooked mutton before and after freeze-thawing.

[0129] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred arrangement scheme, a person skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A process for removing the odor of cooked mutton, characterized in that: The following steps are involved: Step 1, lamb pretreatment: Select the muscle tissue from the hind leg of the lamb, cut it into pieces, wash it and set aside; Step 2, soak and rinse: Place the mutton chunks in a soaking solution with a pH value of 8 to 9 for 7 to 8 hours, changing the soaking solution every 10 to 20 minutes; Step 3, cooking: Place the soaked mutton chunks in a cooking liquid with a pH value of 8 to 9, cook over high heat for 15 to 25 minutes, then turn to low heat and continue cooking for 40 to 60 minutes, then remove and cool naturally to room temperature; Step 4, freezing and thawing: The cooked and matured mutton chunks are frozen in an ultra-fast manner and placed in a -20°C freezer; before consumption, the frozen matured mutton is taken out and placed in a 4°C refrigerator for slow thawing.

2. The process for removing the odor of cooked mutton according to claim 1, characterized in that: In step 2, the soaking liquid is food grade sodium hydroxide or sodium carbonate solution, pH value is 8.79, and the soaking time is 7.8h.

3. The process for removing the odor of cooked mutton according to claim 1, characterized in that: In step 3, the cooking liquid is a food grade sodium hydroxide or sodium carbonate solution with a pH value of 8.

49.

4. The process for removing the odor of cooked mutton according to claim 1, characterized in that: In step 4, the ultra-fast freezing method is liquid nitrogen freezing.

5. A deodorized and cooked mutton, characterized in that: The cooked mutton is prepared by the odor removal process as described in claims 1 to 4.

6. The deodorized and cooked mutton according to claim 5, characterized in that: The flavor substances providing mutton smell include caproic acid, heptanoic acid, caprylic acid, 4-methyloctanoic acid and capric acid, and the content ranges of each flavor substance are 225.23±0.42~252.63±2.2μg / kg, 129.95±0.18~153.6±1.98μg / kg, 526.53±0.15~541.56±0.53μg / kg, 29.86±0.45~33.41±0.6μg / kg and 150.44±0.63~165.24±1.1μg / kg respectively.

Images