Method for reducing peculiar smell of marinated pork intestines and improving quality of marinated pork intestines

Abstract

The invention discloses a method for reducing peculiar smell and improving quality of marinated pork intestines. The method comprises the following steps: step 1, pretreating fresh pork intestines until no macroscopic impurities and no obvious peculiar smell exist; step 2, uniformly stirring the pretreated pork intestines and compound protease, and pickling for 1-2 hours; step 3, blanching the pickled pork intestines for 3-5 minutes, so that the surface temperature of the pork intestines is rapidly cooled to 25 DEG C or below; and step 4, adding a marinating material into the rapidly cooled pork intestines, marinating for 50-70 minutes, taking out the marinated pork intestines, reducing the central temperature of the pork intestines to-18 DEG C or below to obtain marinated pork intestines, and freezing and storing the marinated pork intestines, wherein the marinating material in the step 4 comprises ethyl maltol, and the mass ratio of the compound protease to the ethyl maltol is 40: 1. According to the invention, the peculiar smell of the marinated pork intestines can be effectively reduced, the quality of the marinated pork intestines is greatly improved, and the preparation process is simple and is beneficial to large-scale industrial production of the marinated pork intestines.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and more specifically, to a method for reducing the odor and improving the quality of braised pig intestines. Background Art

[0002] Pig intestines, namely pig intestines, pig large intestines, and pig intestines, are a common pig offal food. Pig intestines are cold in nature and have the effects of moistening dryness, replenishing deficiency, relieving cough and stopping bleeding. They can be used to treat symptoms such as prolapse, hemorrhoids, blood in the stool, and constipation, and have high edible value. However, pig intestines have a typical fishy smell and "organ smell". Even if a complicated treatment process is used, the odor elimination effect is not ideal. In order to reduce the odor of braised pig intestines, most people improve the marinade materials to reduce the odor of pig intestines. For example, the invention patent with publication number CN110367465A discloses a braised process for pig intestines. The ratio of the marinade base material and the seasoning bag used in the braised process is based on the theory of traditional Chinese medicine and existing cooking technology, and includes the following steps: (1) according to weight fraction, take 1-2 parts of red fruit slices, 3-5 parts of peppercorns, 1-2 parts of turmeric, 0.2-0.4 parts of roasted licorice, 3-8 parts of dried ginger slices, and 3-5 parts of star anise, wash them separately, dry them in the sun, sterilize them, and then grind them into granules; (2 ) After the particles are mixed evenly, they are stir-fried at a constant temperature of 120-150° C. for 30-60 minutes, and then crushed to obtain a powdery intermediate; (3) The powdery intermediate is mixed with 0.1-0.2 parts of allicin, 20-30 parts of baking soda, 3-5 parts of papain and 3-5 parts of edible starch at 15-25° C. for 10-60 minutes to obtain a marinade base; (4) Water, rice wine, vinegar and salt are added to the marinade base and boiled for 30 minutes to 6 hours to obtain a marinade; (5) The pig intestines are placed in the marinade and boiled for 30-50 minutes, and the pig intestines are taken out and vacuum-packed to obtain the marinated pig intestines. The above-mentioned production process of braised pork intestines has the following obvious defects: (1) the use of aromatic marinade to marinate the pork intestines can only mask a small part of the fishy smell, and has limited effect on reducing the odor of the braised pork intestines, making it difficult to improve the quality of the braised pork intestines; (2) the production process of the marinade is cumbersome, which is not conducive to controlling product quality consistency in industrial production. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0004] Another object of the present invention is to provide a method for reducing the odor and improving the quality of braised pig intestines, which can effectively reduce the odor of braised pig intestines, greatly improve the quality of braised pig intestines, and has a simple production process, which is conducive to large-scale industrial production of braised pig intestines.

[0005] In order to achieve these purposes and other advantages according to the present invention, a method for reducing the odor and improving the quality of braised pig intestines is provided, comprising:

[0006] Step 1: Pretreatment of pig intestines: Pretreatment of fresh pig intestines until there are no visible impurities and no obvious odor;

[0007] Step 2: marinating the pig intestines: mix the pre-treated pig intestines and compound protease evenly and marinate for 1 to 2 hours;

[0008] Step 3, blanching the pig intestines: add green onions, ginger and cooking wine to the pig intestines pickled in step 2 and blanch for 3 to 5 minutes, quickly take out the pig intestines and quickly cool the surface temperature of the pig intestines to below 25°C;

[0009] Step 4, stewing the pig intestines: adding stewing materials to the pig intestines rapidly cooled in step 3 and stewing for 50 to 70 minutes, taking out the stewed pig intestines and lowering the central temperature of the pig intestines to below -18°C, obtaining stewed pig intestines, and freezing and storing;

[0010] Among them, the added amount of the composite protease in step 2 is 0.1-0.5% of the total mass of the pretreated large intestine, the marinated material in step 4 includes ethyl maltol, and the mass ratio of the composite protease to ethyl maltol is 40:1.

[0011] Preferably, the pretreatment process of the pig intestine in step 1 comprises: adding baking soda, white vinegar, starch and soybean oil to the fresh pig intestine in sequence and then washing it, repeating the process for several times, and removing polyps and 20% to 25% of fat during the washing process or in the interval between two washings, until the pig intestine is free of impurities visible to the naked eye and obvious odor.

[0012] Preferably, the pickling temperature in step 2 is 20-45°C.

[0013] Preferably, in step 3, the method for rapidly cooling the surface temperature of the pig intestines to below 25° C. is: rapidly taking out the pig intestines after blanching and soaking them in ice water to cool them.

[0014] Preferably, the method for lowering the central temperature of the pig intestine to below -18°C in step 4 is: taking out the braised pig intestine, wrapping it with aluminum plating, and then quickly freezing it in a spiral quick freezer to below -18°C.

[0015] Preferably, the marinade in step 4 further includes salt, crystal sugar, sugar color, monosodium glutamate, white pepper, cooking wine, maltose syrup, white wine, straw mushroom dark soy sauce, ethyl maltol, and red pigment.

[0016] Preferably, the marinated ingredients in step 4 further include red date juice fermented by yeast and fresh red date pieces, and the mass ratio of the red date juice, fresh red date pieces and composite yeast is 8-10:5-8:1.

[0017] The present invention further claims protection for the braised pork intestines product prepared by the method for reducing the odor and improving the quality of the braised pork intestines.

[0018] The present invention has at least the following beneficial effects:

[0019] First, the method for reducing the odor and improving the quality of braised pig intestines provided by the present invention adopts the process steps of washing-marinating-blanching-marinating, and adds the step of marinating the pig intestines with a composite protease between washing and blanching, and the pig intestines are marinated to remove the fishy smell, thereby reducing the concentration of indole compounds in the pig intestines and removing part of the odor of the pig intestines, thereby reducing the odor of the pig intestines and significantly improving the flavor of the braised pig intestines;

[0020] Secondly, in the method for reducing the odor and improving the quality of braised pig intestines provided by the present invention, the pig intestines are first pickled with a composite protease before heat processing, which can also reduce the cooking loss of the pig intestines and improve the yield of the pig intestines; at the same time, after the pig intestines are pickled with the composite protease, the surface of the pig intestines becomes rough, and obvious depressions and cracks appear. This is because the protein is hydrolyzed, resulting in the breakage and loosening of the meat structure, which enhances the tenderness of the pig intestines, making the braised pig intestines softer in taste and easier to be digested and absorbed by the human body;

[0021] Thirdly, the method for reducing the odor and improving the quality of braised pig intestines provided by the present invention uses a composite protease to remove the fishy smell of pig intestines during the pickling process, and adds a specific aromatic substance ethyl maltol during the pickling process to mask the odor of a part of the pig intestines, thereby further eliminating the odor of the pig intestines. At the same time, the present application screens the mass ratio of the composite protease and ethyl maltol, accurately controls the optimal ratio of the removal and masking of the odor of the pig intestines, and obtains the braised pig intestines with the best flavor;

[0022] Fourthly, the method for reducing the odor and improving the quality of braised pig intestines provided by the present invention adds red date juice fermented by yeast and fresh red date pieces to the marinating materials. In the initial stage of marinating, the rich carbonyl compounds in the fresh red date pieces react with the amino compounds in the pig intestines to form Schiff bases, and then generate reactive ketosylamines to form aroma precursors. In the later stage, the aroma precursors are used as substrates to further split sugars and release amino groups to form various flavor substances, thereby improving the flavor of the braised pig intestines. The red date juice fermented by yeast contains a large amount of metabolites, and the special flavor of the metabolites can cover up the fishy smell of the pig intestines, thereby improving the sensory experience of the braised pig intestines.

[0023] Fifth, the method for reducing the odor and improving the quality of braised pig intestines provided by the present invention has a precise process, is suitable for industrial large-scale production, and has high consistency in product quality.

[0024] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1Sensory evaluation radar charts of Examples 1 to 2 and Comparative Examples 1 to 8 of the present invention;

[0026] Figure 2 This is a physical picture of the braised pig intestines prepared in Example 1 of the present invention before freezing;

[0027] Figure 3 This is a physical picture of the braised pig intestines prepared in Example 1 of the present invention after being frozen;

[0028] Figure 4 This is a scanning electron microscope image of braised pig intestines pickled with different amounts of composite protease in one technical solution of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can implement the invention with reference to the description.

[0030] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0031] Example 1

[0032] Step 1: Pretreatment of pig intestines: Take 10 kg of fresh pig intestines, add baking soda, white vinegar, starch and soybean oil to the fresh pig intestines in sequence, and then wash them. Repeat this process for several times, and remove polyps and 20% of fat during the washing process or between two washings, until there is no impurity visible to the naked eye and no obvious odor in the pig intestines.

[0033] Step 2, pickling the pig intestines: the pre-treated pig intestines and the compound protease are mixed evenly and then pickled for 1 hour; wherein the compound protease is purchased from Zhejiang Tianhe Food Biological Co., Ltd., and the addition amount of the compound protease is 0.4% of the total mass of the pre-treated pig intestines;

[0034] Step 3, add 4-5 scallion segments, 4-5 ginger segments and an appropriate amount of cooking wine to the pig intestines pickled in step 2, blanch for 3 minutes, quickly take out the pig intestines and soak them in ice water to cool them down, so that the surface temperature of the pig intestines quickly cools down to below 25°C;

[0035] Step 4: add the marinade ingredients to the pig intestines rapidly cooled in step 3 and marinate for 60 minutes, take out the marinated pig intestines, wrap them with aluminized film, and then freeze them in a spiral quick freezer to below -18°C. The packaging machine is not completely vacuumed, the vacuuming time is 10 seconds, and the pressure is 0.08-0.1Mpa. The marinated pig intestines are obtained. Figure 2 As shown, after frozen storage, the actual Figure 3 As shown;

[0036] The marinade ingredients include 0.10-0.14kg of salt, 0.14-0.18kg of rock sugar, 0.7-0.9kg of sugar color, 0.17-0.18kg of monosodium glutamate, 0.03-0.05kg of white pepper, 0.1-0.2kg of cooking wine, 0.08-0.12kg of maltose syrup, 0.1-0.2kg of white wine, 0.22-0.26kg of straw mushroom dark soy sauce, 0.02-0.04kg of red pigment and ethyl maltol, and the mass ratio of the composite protease to ethyl maltol is 40:1.

[0037] Example 2

[0038] Step 1: Pretreatment of pig intestines: Take 10 kg of fresh pig intestines, add baking soda, white vinegar, starch and soybean oil to the fresh pig intestines in sequence, and then wash them. Repeat this process for several times, and remove polyps and 20% of fat during the washing process or between two washings, until there is no impurity visible to the naked eye and no obvious odor in the pig intestines.

[0039] Step 2, pickling the pig intestines: the pre-treated pig intestines and the compound protease are mixed evenly and then pickled for 1 hour; wherein the compound protease is purchased from Zhejiang Tianhe Food Biological Co., Ltd., and the addition amount of the compound protease is 0.4% of the total mass of the pre-treated pig intestines;

[0040] Step 3, add 4-5 scallion segments, 4-5 ginger segments and an appropriate amount of cooking wine to the pig intestines pickled in step 2, blanch for 3 minutes, quickly take out the pig intestines and soak them in ice water to cool them down, so that the surface temperature of the pig intestines quickly cools down to below 25°C;

[0041] Step 4, adding the marinade ingredients to the pig intestines rapidly cooled in step 3 and marinating for 60 minutes, taking out the marinated pig intestines, wrapping them with aluminum, and then quickly freezing them in a spiral quick freezer to below -18°C, the packaging machine is not completely vacuumed, the vacuuming time is 10 seconds, the pressure is 0.08-0.1Mpa, and the marinated pig intestines are obtained and frozen for storage;

[0042] The marinade ingredients include 0.10-0.14kg of salt, 0.14-0.18kg of rock sugar, 0.7-0.9kg of sugar color, 0.17-0.18kg of monosodium glutamate, 0.03-0.05kg of white pepper, 0.1-0.2kg of cooking wine, 0.08-0.12kg of maltose syrup, 0.1-0.2kg of white wine, 0.22-0.26kg of straw mushroom soy sauce, 0.02-0.04kg of red pigment, ethyl maltol, red date juice fermented by yeast and fresh red date pieces. The mass ratio of the composite protease to ethyl maltol is 40:1, and the mass ratio of the red date juice, fresh red date pieces and composite yeast is 8:8:1.

[0043] Example 3

[0044] Step 1: Pretreatment of pig intestines: Take 10 kg of fresh pig intestines, add baking soda, white vinegar, starch and soybean oil to the fresh pig intestines in sequence, and wash them repeatedly. During the washing process or between two washings, remove polyps and 25% of fat until there is no visible impurities and obvious odor in the pig intestines.

[0045] Step 2, pickling the pig intestines: the pre-treated pig intestines and the compound protease are mixed evenly and then pickled for 2 hours; wherein the compound protease is purchased from Zhejiang Tianhe Food Biological Co., Ltd., and the addition amount of the compound protease is 0.5% of the total mass of the pre-treated pig intestines;

[0046] Step 3, add 4-5 scallion segments, 4-5 ginger segments and an appropriate amount of cooking wine to the pig intestines pickled in step 2, blanch them in water for 5 minutes, quickly take out the pig intestines and soak them in ice water to cool them down, so that the surface temperature of the pig intestines quickly cools down to below 25°C;

[0047] Step 4, adding the marinade ingredients to the pig intestines rapidly cooled in step 3 and marinating for 50 minutes, taking out the marinated pig intestines, wrapping them with aluminum, and then quickly freezing them in a spiral quick freezer to below -18°C, the packaging machine is not completely vacuumed, the vacuuming time is 10 seconds, the pressure is 0.08-0.1Mpa, and the marinated pig intestines are obtained and frozen for storage;

[0048] The marinade ingredients include 0.10-0.14kg of salt, 0.14-0.18kg of rock sugar, 0.7-0.9kg of sugar color, 0.17-0.18kg of monosodium glutamate, 0.03-0.05kg of white pepper, 0.1-0.2kg of cooking wine, 0.08-0.12kg of maltose syrup, 0.1-0.2kg of white wine, 0.22-0.26kg of straw mushroom dark soy sauce, 0.02-0.04kg of red pigment and ethyl maltol, and the mass ratio of the composite protease to ethyl maltol is 40:1.

[0049] Example 4

[0050] Step 1: Pretreatment of pig intestines: Take 10 kg of fresh pig intestines, add baking soda, white vinegar, starch and soybean oil to the fresh pig intestines in sequence, and wash them repeatedly. During the washing process or between two washings, remove polyps and 25% of fat until there is no visible impurities and obvious odor in the pig intestines.

[0051] Step 2, pickling pig intestines: the pre-treated pig intestines and compound protease are mixed evenly and pickled for 1.5 hours; wherein the compound protease is purchased from Zhejiang Tianhe Food Biological Co., Ltd., and the addition amount of the compound protease is 0.1% of the total mass of the pre-treated pig intestines;

[0052] Step 3, add 4-5 scallion segments, 4-5 ginger segments and an appropriate amount of cooking wine to the pig intestines pickled in step 2, blanch them in water for 4 minutes, quickly take out the pig intestines and soak them in ice water to cool them down, so that the surface temperature of the pig intestines quickly cools down to below 25°C;

[0053] Step 4, adding the marinade ingredients to the pig intestines rapidly cooled in step 3 and marinating for 70 minutes, taking out the marinated pig intestines, wrapping them with aluminum plating, and then quickly freezing them in a spiral quick freezer to below -18°C, the packaging machine is not completely vacuumed, the vacuuming time is 10 seconds, the pressure is 0.08-0.1Mpa, and the marinated pig intestines are obtained and frozen for storage;

[0054] The marinade ingredients include 0.10-0.14kg of salt, 0.14-0.18kg of rock sugar, 0.7-0.9kg of sugar color, 0.17-0.18kg of monosodium glutamate, 0.03-0.05kg of white pepper, 0.1-0.2kg of cooking wine, 0.08-0.12kg of maltose syrup, 0.1-0.2kg of white wine, 0.22-0.26kg of straw mushroom dark soy sauce, 0.02-0.04kg of red pigment and ethyl maltol, and the mass ratio of the composite protease to ethyl maltol is 40:1.

[0055] Comparative Examples 1 to 5

[0056] Step 1, same as in Example 1;

[0057] Step 2: In the process of pickling the pig intestines in Comparative Examples 1 to 5, Comparative Example 1 has no pickling process, and Comparative Examples 2 to 5 use lipase, papain, characteristic yeast extract and basic yeast extract to replace the composite protease as pickling materials for pickling; wherein the characteristic yeast extract and the basic yeast extract are characteristic flavor YE and basic umami YE purchased from Angel Yeast Co., Ltd. respectively;

[0058] Step 3, same as in Example 1;

[0059] In step 4, the marinade materials are 0.10-0.14 kg of salt, 0.14-0.18 kg of crystal sugar, 0.7-0.9 kg of sugar color, 0.17-0.18 kg of monosodium glutamate, 0.03-0.05 kg of white pepper, 0.1-0.2 kg of cooking wine, 0.08-0.12 kg of maltose syrup, 0.1-0.2 kg of white wine, 0.22-0.26 kg of straw mushroom dark soy sauce, 0.02-0.04 kg of red pigment and ethyl maltol. The mass ratio of the marinade to ethyl maltol is 40:1, and the rest is the same as in Example 1.

[0060] Comparative Example 6

[0061] Step 1, same as in Example 1;

[0062] Step 2: Same as in Example 1;

[0063] Step 3, same as in Example 1;

[0064] In step 4, the marinade ingredients are 0.10-0.14 kg of salt, 0.14-0.18 kg of crystal sugar, 0.7-0.9 kg of sugar color, 0.17-0.18 kg of monosodium glutamate, 0.03-0.05 kg of white pepper, 0.1-0.2 kg of cooking wine, 0.08-0.12 kg of maltose syrup, 0.1-0.2 kg of white wine, 0.22-0.26 kg of straw mushroom dark soy sauce, and 0.02-0.04 kg of red pigment, and the rest are the same as in Example 1.

[0065] Comparative Examples 7 to 8

[0066] Step 1, same as in Example 1;

[0067] Step 2: Same as in Example 1;

[0068] Step 3, same as in Example 1;

[0069] In step 4, the marinade materials are 0.10-0.14 kg of salt, 0.14-0.18 kg of crystal sugar, 0.7-0.9 kg of sugar color, 0.17-0.18 kg of monosodium glutamate, 0.03-0.05 kg of white pepper, 0.1-0.2 kg of cooking wine, 0.08-0.12 kg of maltose syrup, 0.1-0.2 kg of white wine, 0.22-0.26 kg of straw mushroom dark soy sauce, 0.02-0.04 kg of red pigment and ethyl maltol. In comparative examples 7 and 8, the mass ratios of the composite protease and ethyl maltol are 8:1 and 80:1, respectively, and the rest are the same as in embodiment 1.

[0070] The differences between Comparative Examples 1 to 5 and Example 1 are: Comparative Example 1 is relative to Example 1, and Comparative Example 1 has no pickling process; Comparative Example 2 is relative to Example 1, and Comparative Example 2 uses lipase as a pickling agent for pickling; Comparative Example 3 is relative to Example 1, and Comparative Example 3 uses papain as a pickling agent for pickling; Comparative Example 4 is relative to Example 1, and Comparative Example 4 uses characteristic yeast extract as a pickling agent for pickling; Comparative Example 5 is relative to Example 1, and Comparative Example 5 uses basic yeast extract as a pickling agent for pickling.

[0071] The differences between Comparative Examples 6 to 8 and Example 1 are: relative to Example 1, the marinating material used in step 4 of Comparative Example 6 does not contain ethyl maltol; relative to Example 1, the mass ratio of the composite protease and ethyl maltol in the marinating material used in step 4 of Comparative Example 7 is 8:1; relative to Example 1, the mass ratio of the composite protease and ethyl maltol in the marinating material used in step 4 of Comparative Example 8 is 80:1.

[0072] Example 2 is based on Example 1, and the marinated materials in step 4 also include red date juice fermented by yeast and fresh red date pieces, and the mass ratio of the red date juice, fresh red date pieces and composite yeast is 8:8:1.

[0073] 1. Sensory evaluation and analysis

[0074] Combined with the characteristics of the samples, the sensory scoring system was developed in accordance with the requirements of GB / T 22210-2008 "Specification for Sensory Evaluation of Meat and Meat Products". 50 professionally trained sensory evaluators were selected, 25 males and 25 females, aged between 20 and 40 years old. The sensory evaluation adopted a 10-point system. The evaluators did not interfere with each other during the entire tasting and scoring process, and the results were averaged. The specific scoring criteria are shown in Table 1.

[0075] Table 1 Sensory evaluation standards

[0076]

[0077] The sensory scoring results of the braised pig intestines prepared in Example 1, Example 2 and Comparative Examples 1 to 8 are shown in Table 2. The sensory scoring radar chart of the braised pig intestines prepared in Example 1, Example 2 and Comparative Examples 1 to 8 is shown in Table 2. Figure 1 shown.

[0078] Table 2 Sensory scores of braised pork intestines obtained by different preparation methods

[0079]

[0080] Note: Different lowercase letters in the table indicate significant differences, i.e. P<0.05.

[0081] from Figure 1 As can be seen from Table 2, the aroma (corresponding to smell), taste (corresponding to flavor) and mouthfeel (corresponding to chewiness) of Example 1 are all good, the appearance evaluation (corresponding to color) is high, and the comprehensive preference (corresponding to comprehensive evaluation) is significantly higher than that of Comparative Examples 1 to 5.

[0082] Example 2 is based on Example 1, and in step 4, the marinated material further includes red date juice and fresh red date pieces after yeast fermentation, and the mass ratio of the red date juice, fresh red date pieces and composite yeast is 8:8:1. The marinated pig intestines prepared in Example 2 have a gain in aroma, appearance evaluation, taste and comprehensive preference compared to the marinated pig intestines prepared in Example 1, and a slight decrease in taste, which shows that adding fermented red date juice and fresh red date pieces to the marinated material is beneficial to improving the aroma, taste, appearance evaluation and comprehensive preference of the marinated pig intestines. This is because the rich carbonyl compounds in the fresh red date pieces react with the amino compounds in the pig intestines in the initial stage of marinating to form Schiff bases, and then generate reactive ketosylamines to form aroma precursors. In the later stage, the aroma precursors are used as substrates to further cleave sugars and release amino groups to form various flavor substances, thereby improving the flavor of the marinated pig intestines; the red date juice after yeast fermentation contains a large number of metabolites, and the special flavor of the metabolites can cover up the fishy smell of the pig intestines and improve the sensory experience of the marinated pig intestines.

[0083] Comparative Example 1 does not have a pickling step. The aroma, taste and mouthfeel of the braised pig intestines prepared in Comparative Example 1 are significantly reduced compared to the braised pig intestines prepared in Example 1, and the appearance evaluation and comprehensive preference are also significantly reduced; this shows that the use of a composite protease to pickle the pig intestines before heat processing can effectively improve the aroma, taste and mouthfeel of the braised pig intestines, and is also beneficial to improving the appearance and comprehensive preference of the braised pig intestines.

[0084] Comparative Example 2 uses lipase as a marinating agent for marinating. The aroma, appearance evaluation and comprehensive preference of the braised pig intestines prepared in Comparative Example 2 are significantly lower than those of the braised pig intestines prepared in Example 1, and the decrease in taste and flavor is relatively small, but compared with the braised pig intestines prepared in Comparative Example 1, the improvement in aroma is not obvious, which shows that the use of lipase to marinate pig intestines before heat processing is obviously not as good as the use of composite protease to marinate pig intestines before heat processing. Even after the use of lipase to marinate pig intestines before heat processing, the effect on the aroma of the braised pig intestines is not significant.

[0085] Comparative Example 3 uses papain as a pickling material for pickling. The aroma, taste, mouthfeel, appearance evaluation and comprehensive preference of the braised pig intestines prepared in Comparative Example 3 are significantly reduced compared with the braised pig intestines prepared in Example 1. Compared with the braised pig intestines prepared in Comparative Example 1, the taste and appearance evaluation are slightly improved but not by much, and there is no difference in taste and comprehensive preference, and even the aroma is reduced. This shows that the use of papain to pickle the pig intestines before heat processing does not improve the taste, mouthfeel, appearance evaluation and comprehensive preference of the braised pig intestines much, and may even reduce the aroma of the braised pig intestines.

[0086] Comparative Example 4 uses the characteristic yeast extract as the marinating material for marinating. The aroma, appearance evaluation and comprehensive preference of the braised pig intestines prepared in Comparative Example 4 are greatly reduced compared with the braised pig intestines prepared in Example 1, and the taste decreases less. Compared with the braised pig intestines prepared in Comparative Example 1, the taste, aroma, appearance evaluation and comprehensive preference are improved but the improvement is not large, and the taste is improved more. This shows that the use of characteristic yeast extract to marinate the pig intestines before heat processing does not improve the aroma, taste, appearance evaluation and comprehensive preference of the braised pig intestines much, but the taste is greatly improved.

[0087] Comparative Example 5 uses basic yeast extract as the marinade. The aroma, appearance evaluation, taste, mouthfeel and comprehensive preference of the braised pig intestine prepared in Comparative Example 5 are significantly reduced compared with the braised pig intestine prepared in Example 1. Compared with the braised pig intestine prepared in Comparative Example 1, the aroma, taste, mouthfeel and comprehensive preference are reduced, and the appearance evaluation is slightly improved. This shows that the use of yeast extract to marinate pig intestines before heat processing slightly improves the appearance evaluation of braised pig intestines, but greatly affects the aroma, taste, mouthfeel and comprehensive preference of the braised pig intestines.

[0088] In summary, using compound protease to marinate pig intestines before heat processing can greatly improve the aroma, taste, mouthfeel, appearance evaluation and overall preference of marinated pig intestines. This is because compound protease catalyzes the hydrolysis of protein and breaks it down into smaller peptides and amino acids, breaking the meat structure of pig intestines into looseness, increasing the tenderness of pig intestines, making the pig intestines taste softer, and also helping to release flavor substances, improving the taste of pig intestines, and smaller protein fragments are easier to be digested and absorbed by the human body. Figure 4 The scanning electron microscope image of the pig intestines can be confirmed that the surface of the pig intestines pickled with compound protease is relatively uniform, the structure is tight, and there are almost no visible gaps or cracks. After the pig intestines are pickled with compound protease before heat processing, the structure of the pig intestine surface changes, obvious depressions and cracks are produced, and the discontinuity of the pig intestine surface is increased. This change affects the physical properties of the pig intestines, such as texture and appearance, and also has a positive effect on the release of flavor infrared nutrients in the braised pig intestines. With the increase of the amount of compound protease, the gaps and cracks on the surface of the pig intestines are further expanded, the surface discontinuity becomes more and more obvious, and the surface roughness increases. The surface of the pig intestines pickled with 0.5% compound protease appears extremely rough, with a large number of cracks and cavities, and the structure is almost about to lose its original compactness, affecting the eating experience, resulting in excessive softening of the braised pig intestines. The addition of compound protease cannot exceed 0.5%.

[0089] The braised material used in step 4 of comparative example 6 does not contain ethyl maltol, lacks the synergistic effect of ethyl maltol and compound protease, and the braised pig intestines prepared in comparative example 6 have a significantly reduced aroma, taste, mouthfeel, appearance evaluation and comprehensive preference compared to the braised pig intestines prepared in Example 1, wherein the reduction in aroma and taste reaches 42.2% and 66.6%. This shows that the lack of ethyl maltol and compound protease in the braised material will seriously affect the aroma, taste, mouthfeel, appearance evaluation and comprehensive preference of the braised pig intestines, because ethyl maltol has a caramel aroma and can be used as a flavor enhancer in food. The addition of ethyl maltol to the braised pig intestines helps to mask the peculiar smell that is difficult to eliminate. After scientifically matching with the compound protease, it can synergistically reduce the peculiar smell of the braised pig intestines and improve the quality of the pig intestines.

[0090] The mass ratio of the compound protease and ethyl maltol in the marinating material used in step 4 of comparative example 7 is 8:1; the smell, taste and comprehensive preference of the marinated pig intestines prepared in comparative example 7 are significantly reduced compared with the marinated pig intestines prepared in example 1, and the taste and appearance evaluation are slightly reduced. The mass ratio of the compound protease and ethyl maltol in the marinating material used in step 4 of comparative example 8 is 80:1; the taste, taste and comprehensive preference of the marinated pig intestines prepared in comparative example 8 are significantly reduced compared with the marinated pig intestines prepared in example 1, but the aroma and appearance evaluation decrease less, which indicates that the ratio of the compound protease and ethyl maltol has a greater influence on the smell, taste, taste, appearance evaluation and comprehensive preference of the marinated pig intestines. When the ratio of the compound protease and ethyl maltol is 40:1, it has a greater positive influence on the aroma, taste, taste, appearance evaluation and comprehensive preference of the marinated pig intestines.

[0091] 2. Evaluation of volatile flavor compounds (indole compound content and skatole content)

[0092] The pig intestine sample was crushed and mixed, 3 g of the pig intestine sample was accurately weighed and placed in a 20 mL flavor bottle, and 1.5 μL of internal standard (2-methyl-3-heptanone with a concentration of 0.81 μg / μL) was added.

[0093] Chromatographic conditions: A DB-WAX column (30 m × 0.25 mm × 0.25 μm) from Agilent Technologies, USA, was used, the temperatures of the injector and ion source were 200 °C and 250 °C, respectively, and the helium flow rate was 1 mL / min as the carrier. The initial temperature of the oven was set to 40 °C, and the heating program of the oven was maintained at 40 °C for 3 min, then increased to 120 °C for 3 min, then increased to 120 °C at a rate of 5 °C / min, and then increased to 200 °C at a rate of 10 °C / min and maintained for 13 min.

[0094] Mass spectrometry conditions: ion source B source, ion source temperature 250 °C, transfer line temperature 250 °C, electron energy 70 eV, split ratio between mass spectrometer and olfactometer set to 5:1, full scan mode, scan range 35-500 m / z.

[0095] Qualitative and quantitative identification of volatile flavor compounds: By comparing the spectra with those in the NIST17.L and NIST20.L databases, compounds with a matching degree and purity exceeding 80% (full score is 100%) are selected for qualitative analysis. The area normalization method is used to quantify the compounds, thereby calculating the relative content of various volatile flavor compounds.

[0096] The test results of the volatile compound content in the braised pig intestines prepared in Example 1, Example 2 and Comparative Examples 1 to 8 are shown in Table 3.

[0097] Table 3 Contents of volatile flavor compounds in different braised pig intestines

[0098]

[0099] Note: Different lowercase letters in the table indicate significant differences, i.e. P<0.05.

[0100] As can be seen from the data in Table 3, the braised pig intestines prepared in Example 1 have lower indole and skatole contents than those prepared in Comparative Examples 1 to 8. Indole substances include indole, 2-methyl indole, 3-methyl indole, 4-methyl indole, etc., which are volatile flavor substances unique to pig intestines. Indole substances can produce completely different olfactory experiences at different concentrations. At low concentrations, indole can have a smell similar to the fragrance of flowers, and this characteristic makes it used as an ingredient in some perfumes and spices. However, at high concentrations, indole will emit a strong, not very pleasant smell, similar to the smell of feces or corruption. The indole compounds contained in visceral foods such as pig intestines (pig large intestine) are usually present in higher concentrations, which may cause them to emit a relatively strong smell. For example, skatole (3-methyl indole) makes people have an uncomfortable odor and is also the main odor substance in the odor of pig intestines.

[0101] Comparing the contents of indole substances and skatole in the braised pig intestines prepared in Example 1 and Example 2, the content of indole substances and skatole in the braised pig intestines prepared in Example 2 is lower, and the content of skatole is also lower. This is because adding red date juice and fresh red date pieces fermented by yeast to the marinating material is beneficial to reducing the content of indole substances and skatole in the braised pig intestines; comparing Example 1 and Comparative Examples 1 to 5, the content of indole substances and skatole in the braised pig intestines prepared in Comparative Examples 1 to 5 are higher than those in the braised pig intestines prepared in Example 1. Compound protease pickled pig intestines is beneficial to reducing the content of indole substances and skatole in braised pig intestines; horizontally comparing Example 1 and Comparative Examples 6 to 8, the content of indole substances and skatole in the braised pig intestines prepared in Comparative Examples 6 to 8 are higher than the braised pig intestines prepared in Example 1, compound protease is used to pickle the pig intestines before hot processing of the pig intestines, and ethyl maltol is added to the marinating material to synergistically eliminate the odor of fat intestines with the compound protease, and the ratio of compound protease to ethyl maltol is 40:1, which is beneficial to reducing the content of indole substances and skatole in the braised pig intestines.

[0102] 3. Shear force evaluation

[0103] The samples were tested using a tenderness meter. The braised pig intestines were cut into small pieces of 1cm×0.5cm×0.5cm to measure their shear force values. The samples were tested three times and the average value was taken.

[0104] 4. Evaluation of cooking loss

[0105] After tenderizing the pig intestine, absorb the surface moisture with kitchen paper and weigh the mass after thawing m1. After the pig intestine is marinated according to the process, it is cooled to room temperature and the surface moisture is absorbed with kitchen paper and weighed to obtain the mass after cooking m2. Each group has 3 parallels. The cooking loss rate is calculated according to formula (1).

[0106] Cooking loss rate = (m1-m2) / m1×100% (1)

[0107] 5. Evaluation of the yield of pig intestines

[0108] Drain the fat intestines and use filter paper to absorb the moisture on the inner and outer surfaces of the pig intestines. Use an analytical balance to accurately weigh the mass and record it. The yield is calculated as shown in formula (2):

[0109] Production rate / % = m3 / m4×100% (2)

[0110] In the formula: m3 is the mass of fat intestines after tenderization; m4 is the mass of fat intestines before tenderization.

[0111] The shear force, cooking loss and yield of the braised pig intestines prepared in Example 1, Example 2 and Comparative Examples 1 to 8 were measured, and the results are shown in Table 4.

[0112] Table 4 Shear force, cooking loss and yield of different braised pig intestines

[0113]

[0114] Note: Different lowercase letters in the table indicate significant differences, i.e. P<0.05.

[0115] It can be seen from Table 4 that the braised pig intestines prepared in Example 1 have lower shear force and smaller cooking loss than the braised pig intestines prepared in Comparative Examples 1 to 8, and the braised pig intestines prepared in Example 1 have a higher yield than the braised pig intestines prepared in Comparative Examples 1 to 8. The shear force reflects the tenderness of the meat sample, and the cooking loss reflects the yield of the braised pig intestines during the braising process. The lower the cooking loss, the higher the yield of the braised pig intestines, and the yield reflects the yield of the pig intestines during the pickling process of the braised pig intestines.

[0116] Comparing the indole content and skatole content in the braised pig intestines prepared in Example 1 and Example 2, the cooking loss in the braised pig intestines prepared in Example 2 is smaller, and the yield of pig intestines in the pickling process is larger, but the shear force is larger. This is because adding red date juice and fresh red date pieces after yeast fermentation to the marinating material is beneficial to reducing the cooking loss in the braised pig intestines during the braising process and improving the yield of the braised pig intestines during the pickling process, but the tenderness of the braised pig intestines will be slightly lost; comparing Example 1 with Comparative Examples 1 to 5, although Comparative Example 2 uses lipase as a marinating material to slightly improve the tenderness of the braised pig intestines after pickling, the tenderness of the braised pig intestines prepared in Comparative Examples 3 to 5 is not as good as the braised pig intestines prepared in Example 1. Using a composite protease to marinate the pig intestines before hot processing of the pig intestines is beneficial to improving the yield of the pig intestines during pickling and reducing the cooking loss during the braising process of the pig intestines; Compared with the process of Example 1, the process of preparing braised pig intestines in Examples 1 to 5 has less cooking loss during the braising process and a higher yield of pig intestines during the pickling process; in a horizontal comparison between Example 1 and Comparative Examples 6 to 8, although Comparative Example 6 slightly improves the tenderness of the braised pig intestines after pickling using lipase as a pickling material, the tenderness of the braised pig intestines prepared in Comparative Examples 7 and 8 is not as good as that of the braised pig intestines prepared in Example 1; Compared with the process of Example 1, the process of preparing braised pig intestines in Examples 6 to 8 has less cooking loss during the braising process and a higher yield of pig intestines during the pickling process, a composite protease is used to pickle the pig intestines before hot processing, and ethyl maltol is added to the braising material to synergize with the composite protease to eliminate the odor of fat intestines, and the ratio of the composite protease to ethyl maltol is 40:1, which is beneficial to improving the yield of pig intestines during pickling and reducing the cooking loss during the braising process of pig intestines.

[0117] The number of equipment and processing scale described here are used to simplify the description of the present invention. The application, modification and variation of the method for reducing the odor and improving the quality of braised pig intestines and the braised pig intestines product prepared by the present invention are obvious to those skilled in the art.

[0118] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for reducing the odor and improving the quality of braised pig intestines, characterized in that: include: Step 1: Pretreatment of pig intestines: Pretreatment of fresh pig intestines until there are no visible impurities and no obvious odor; Step 2: marinating the pig intestines: mix the pre-treated pig intestines and compound protease evenly and marinate for 1 to 2 hours; Step 3, blanching the pig intestines: add green onions, ginger and cooking wine to the pig intestines pickled in step 2 and blanch for 3 to 5 minutes, quickly take out the pig intestines and quickly cool the surface temperature of the pig intestines to below 25°C; Step 4, stewing the pig intestines: adding stewing materials to the pig intestines rapidly cooled in step 3 and stewing for 50 to 70 minutes, taking out the stewed pig intestines and lowering the central temperature of the pig intestines to below -18°C, obtaining stewed pig intestines, and freezing and storing; Among them, the added amount of the composite protease in step 2 is 0.1-0.5% of the total mass of the pretreated large intestine, the marinated material in step 4 includes ethyl maltol, and the mass ratio of the composite protease to the ethyl maltol is 40:

1.

2. The method for reducing the odor and improving the quality of braised pig intestines according to claim 1, characterized in that: The pretreatment process of the pig intestine in step 1 includes: adding baking soda, white vinegar, starch and soybean oil to the fresh pig intestine in turn and washing it, repeating it for many times, and removing polyps and 20% to 25% of fat during the washing process or in the interval between two washings, until the pig intestine has no impurities visible to the naked eye and obvious odor.

3. The method for reducing the odor and improving the quality of braised pig intestines according to claim 2, characterized in that: In step 2, the pickling temperature is 20-45°C.

4. The method for reducing the odor and improving the quality of braised pig intestines according to claim 3, characterized in that: The method for rapidly cooling the surface temperature of the pig intestines to below 25° C. in step 3 is as follows: rapidly taking out the pig intestines after blanching and soaking them in ice water to cool them.

5. The method for reducing the odor and improving the quality of braised pig intestines according to claim 4, characterized in that: The method for lowering the central temperature of the pig intestine to below -18°C in step 4 is as follows: taking out the braised pig intestine, wrapping it with aluminum plating, and then quickly freezing it in a spiral quick freezer to below -18°C.

6. The method for reducing the odor and improving the quality of braised pig intestines according to claim 5, characterized in that: The marinade ingredients in step 4 also include salt, crystal sugar, sugar color, monosodium glutamate, white pepper, cooking wine, maltose syrup, white wine, straw mushroom dark soy sauce, ethyl maltol, and red pigment.

7. The method for reducing the odor and improving the quality of braised pig intestines according to claim 6, characterized in that: In step 4, the marinated ingredients also include red date juice fermented by yeast and fresh red date pieces, and the mass ratio of the red date juice, the fresh red date pieces and the composite yeast is 8-10:5-8:

1.

8. The braised pig intestine product prepared by the method for reducing the odor and improving the quality of braised pig intestine as described in any one of claims 1 to 7.

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