A method for producing low-temperature refined cured lard

Abstract

The application belongs to the technical field of lard, and particularly relates to a production method of low-temperature refined cured lard, which comprises the following steps: raw material selection, trimming and cleaning, cutting, curing, vacuum refining, oil residue separation, filtration, filling and preservation, and the like, so as to obtain a product. The application solves the problems that lard is prone to deterioration in the production process of the prior art, and the product cannot be quantitatively added. Through the combination of curing and vacuum refining, the acid value and peroxide value of the cured lard product are obviously reduced, the shelf life of the lard is effectively prolonged, and the quantitative packaging and addition of the cured lard product are realized.

Description

Technical Field

[0001] This invention belongs to the field of lard processing technology, specifically relating to a method for producing low-temperature refined and cured lard. Background Technology

[0002] Lard, also known as pork fat, is an animal oil extracted from the fatty tissue of healthy pigs. With the diversification of meat product development, the production of whole pork carcasses is declining, and meat sales are mainly focused on chilled, frozen, and packaged meat, resulting in a large surplus of pork fat such as belly meat, pork fat, streaky lard, and pork back fat. my country is the world's largest producer of lard, and how to fully utilize pork fat resources to improve the economic efficiency of enterprises is one of the urgent problems to be solved.

[0003] Cured lard is a traditional lard product, generally used as a base for braising sauces. Salt is used to enhance flavor, remove fishy odors, kill bacteria, inhibit bacterial growth, and preserve freshness, thus improving the flavor of lard products and enabling long-term storage.

[0004] Currently, all cured lard products on the market are made using traditional methods, without temperature, humidity, or light control. These products lack packaging and proper storage and transportation conditions, resulting in rudimentary production and sales practices. Consequently, the color, flavor, and safety of these products are poor. Furthermore, existing cured lard products are irregularly shaped, making them inconvenient for packaging, storage, transportation, and precise dosage during use.

[0005] Traditional lard refining in my country mainly involves two processes: wet and dry. The wet process involves heating in the presence of moisture, with a lower operating temperature than the dry process. Currently, large-scale factory production primarily uses the steaming method. The main advantages of steaming for extracting animal fats are low cost and simple operation. Disadvantages include longer processing time, higher energy consumption, larger wastewater volume, and the tendency for the fat to hydrolyze, producing free fatty acids that affect quality. The dry process does not add water or uses direct steam, operates at higher temperatures, and has a lower oil yield. In the initial stages of dry refining, due to difficulty in temperature control or prolonged heating, the lard may darken in color, increase in acid value, peroxide value, and malondialdehyde content, resulting in a significant decline in lard quality.

[0006] Lard is prone to oxidation and spoilage. The high-temperature refining process of lard can also negatively impact its quality. With increasing awareness of food safety, the quality changes of oils during continuous heating have gradually become a food safety concern for consumers and a research hotspot for researchers in related fields. Summary of the Invention

[0007] To address the problems in the prior art, this invention provides a method for producing low-temperature refined marinated lard, which solves the problem of lard easily deteriorating in the prior art. By combining marinating with vacuum refining, the acid value and peroxide value of the marinated lard product are significantly reduced, effectively extending the shelf life of the lard.

[0008] To achieve the above technical objectives, the technical solution of the present invention is as follows:

[0009] A method for producing low-temperature refined marinated lard includes the following steps:

[0010] Step 1, Raw material selection:

[0011] The raw materials for lard are frozen lard or fresh lard, using fresh, clean and intact fat tissue from healthy pigs;

[0012] Step 2, Trimming and Cleaning:

[0013] After removing the fragments of muscle, blood, bones, organs, etc. that adhere to it, the dirt is washed away to obtain clean lard raw material;

[0014] Step 3, cut into pieces:

[0015] Cut the lard raw material into relatively uniform blocks and marinate it evenly.

[0016] Step 4, marinating:

[0017] Spread edible salt evenly on the surface of the lard raw material block, and then place it in a light-proof, airtight container to marinate;

[0018] Step 5, Vacuum refining:

[0019] The marinated lard raw material blocks are placed in a pressure vessel, liquid lard is added to form a solid-liquid mixture; then the vessel is sealed and vacuumed, heated with steam, and the pressure is released after refining.

[0020] Step 6, oil-sludge separation:

[0021] The refined solid-liquid mixture is added to an oil residue separator for oil residue separation. The liquid oil enters the oil tank, and the solid residue enters the oil press.

[0022] Step 7, Filtering:

[0023] After sedimentation and filtration, the liquid oil is stored in oil tanks and then bottled for preservation.

[0024] The adipose tissue in step 1 includes lard and fat.

[0025] The clean lard raw material in step 2 is dehydrated by air drying or squeezing.

[0026] The amount of edible salt used in step 4 is 8-20% of the weight of the lard raw material.

[0027] The pickling temperature in step 4 is 0-15℃, and the pickling time is 15-30 days.

[0028] In step 5, the vacuum degree is 0.092-0.098 MPa, the steam heating temperature is 100-120℃, and the time is 1-2 hours. During the steam heating process, stirring is also required, and the stirring speed is 20-100 r / min.

[0029] The pressed oil produced by pressing the solid residue in step 6 enters the oil tank and mixes with the liquid oil phase.

[0030] The pressed oil contains 5-10% solid impurities, and the residual oil content in the pressed oil cake is 6-10%.

[0031] The impurity content of the filtered liquid oil in step 7 is less than 0.2%.

[0032] The filling and storage conditions in step 7 are 0-4℃, and storage and transportation should be carried out in the dark.

[0033] During the pickling process, the role of edible salt mainly includes four aspects: First, the osmotic pressure it generates causes water in the lard to move to the surface, while salt migrates inward, resulting in rapid water loss at the surface and reducing the water activity of the raw material, leading to surface dehydration. Second, it inhibits the growth and reproduction of harmful microorganisms; both the reduction in moisture and the inhibition of microbial activity help control oil oxidation. Third, while washing removes water-soluble impurities, it still leaves behind proteinaceous adhesive substances such as collagen, which denature during heating and refining, damaging the product's color, odor, and other sensory qualities. The salting-out effect of edible salt can remove protein impurities, reduce oil viscosity, and improve its color. Fourth, edible salt enhances the flavor of the lard, improving its sensory quality. Traditional pickling methods expose the oil to air, stimulating microorganisms and endogenous enzymes, easily leading to quality deterioration. This invention improves upon this drawback by using a sealed pickling method.

[0034] Vacuum refining is carried out under negative pressure and in a sealed container, which lowers the boiling point of water in the oil raw materials. Simultaneously, vacuum refining is controlled at relatively low temperatures and low oxygen concentrations (compared to traditional lard refining methods), isolating the lard from air. This is crucial for preserving quality, increasing oil yield, reducing aroma loss, and controlling oxidation. The refined lard products can be uniformly packaged, facilitating storage, transportation, and quantitative addition.

[0035] This invention utilizes salt curing to rapidly reduce the moisture content of lard raw materials, ensuring the material is in a dehydrated state and inhibiting the hydrolysis reaction of the oil. The salt-treated lard raw materials are then vacuum-refined. As pressure changes occur, the dense surface structure breaks down, creating identical voids inside and out, ensuring pressure balance. At this point, the salt allows the inner layer of moisture to continue to seep out rapidly, achieving separation between the oil and water. Under vacuum conditions, the water sublimates directly into gas and is expelled, while the salt continues to promote the seepage of moisture from the inner layer. Due to the interconnectedness and vacuum conditions, the dehydrated lard raw materials can be refined into oil at low temperatures. The combination of salt curing and vacuum refining improves moisture removal efficiency and reduces the water content of the raw materials. Furthermore, the interconnected structure ensures that both the inner and outer layers are refined simultaneously, increasing both the oil yield and extraction efficiency; the quality of the lard is also improved.

[0036] As can be seen from the above description, the present invention has the following advantages:

[0037] 1. This invention solves the problem of easy deterioration of lard in the prior art. By combining pickling and vacuum refining, it significantly reduces the acid value and peroxide value of pickled lard products, effectively extending the shelf life of lard.

[0038] 2. The lard prepared by this invention has a special and good flavor and taste, which can significantly improve the sensory quality of the product.

[0039] 3. The process of this invention is highly controllable, which is conducive to mass production and industrialization while ensuring the quality of lard. Attached Figure Description

[0040] Figure 1 This is a graph showing the change in peroxide value between Embodiment 1 of the present invention and other products.

[0041] Figure 2 This is a graph showing the change in acid value between Example 1 of the present invention and other products. Detailed Implementation

[0042] The present invention will be described in detail with reference to the embodiments, but the claims of the present invention are not intended to limit the scope of the invention.

[0043] Example 1

[0044] A method for producing low-temperature refined marinated lard includes the following steps:

[0045] Step 1, Raw material selection:

[0046] The raw materials for lard are frozen lard or fresh lard, using fresh, clean and intact fat tissue from healthy pigs;

[0047] Step 2, Trimming and Cleaning:

[0048] After removing the fragments of muscle, blood, bones, organs, etc. that adhere to it, the dirt is washed away to obtain clean lard raw material;

[0049] Step 3, cut into pieces:

[0050] Cut the lard raw material into relatively uniform blocks and marinate it evenly.

[0051] Step 4, marinating:

[0052] Spread edible salt evenly on the surface of the lard raw material block, and then place it in a light-proof, airtight container to marinate;

[0053] Step 5, Vacuum refining:

[0054] The marinated lard raw material blocks are placed in a pressure vessel, liquid lard is added to form a solid-liquid mixture; then the vessel is sealed and vacuumed, heated with steam, and the pressure is released after refining.

[0055] Step 6, oil-sludge separation:

[0056] The refined solid-liquid mixture is added to an oil residue separator for oil residue separation. The liquid oil enters the oil tank, and the solid residue enters the oil press.

[0057] Step 7, Filtering:

[0058] After sedimentation and filtration, the liquid oil is stored in oil tanks and then bottled for preservation.

[0059] The adipose tissue in step 1 includes lard and fat.

[0060] The clean lard raw material in step 2 is dehydrated by air drying or squeezing.

[0061] The amount of edible salt used in step 4 is 8% of the mass of the lard raw material.

[0062] The pickling temperature in step 4 is 0℃, and the pickling time is 15 days.

[0063] In step 5, the vacuum degree is 0.092 MPa, the steam heating temperature is 100℃, and the time is 1 hour. During the steam heating process, stirring is also required, and the stirring speed is 20 r / min.

[0064] The pressed oil produced by pressing the solid residue in step 6 enters the oil tank and mixes with the liquid oil phase.

[0065] The pressed oil contains 5% solid impurities, and the residual oil content in the pressed oil cake is 6%.

[0066] The impurity content of the filtered liquid oil in step 7 is 0.19%.

[0067] The filling and storage conditions in step 7 are 0°C and protection from light during storage and transportation.

[0068] Example 2

[0069] A method for producing low-temperature refined marinated lard includes the following steps:

[0070] Step 1, Raw material selection:

[0071] The raw materials for lard are frozen lard or fresh lard, using fresh, clean and intact fat tissue from healthy pigs;

[0072] Step 2, Trimming and Cleaning:

[0073] After removing the fragments of muscle, blood, bones, organs, etc. that adhere to it, the dirt is washed away to obtain clean lard raw material;

[0074] Step 3, cut into pieces:

[0075] Cut the lard raw material into relatively uniform blocks and marinate it evenly.

[0076] Step 4, marinating:

[0077] Spread edible salt evenly on the surface of the lard raw material block, and then place it in a light-proof, airtight container to marinate;

[0078] Step 5, Vacuum refining:

[0079] The marinated lard raw material blocks are placed in a pressure vessel, liquid lard is added to form a solid-liquid mixture; then the vessel is sealed and vacuumed, heated with steam, and the pressure is released after refining.

[0080] Step 6, oil-sludge separation:

[0081] The refined solid-liquid mixture is added to an oil residue separator for oil residue separation. The liquid oil enters the oil tank, and the solid residue enters the oil press.

[0082] Step 7, Filtering:

[0083] After sedimentation and filtration, the liquid oil is stored in oil tanks and then bottled for preservation.

[0084] The adipose tissue in step 1 includes lard and fat.

[0085] The clean lard raw material in step 2 is dehydrated by air drying or squeezing.

[0086] The amount of edible salt used in step 4 is 20% of the mass of the lard raw material.

[0087] The pickling temperature in step 4 is 15℃, and the pickling time is 30 days.

[0088] In step 5, the vacuum degree is 0.098 MPa, the steam heating temperature is 120°C, and the time is 1-2 hours. During the steam heating process, stirring is also required, and the stirring speed is 100 r / min.

[0089] The pressed oil produced by pressing the solid residue in step 6 enters the oil tank and mixes with the liquid oil phase.

[0090] The pressed oil contains 10% solid impurities, and the residual oil content in the pressed oil cake is 10%.

[0091] The impurity content of the filtered liquid oil in step 7 is 0.18%.

[0092] The filling and storage conditions in step 7 are 4°C and protected from light during storage and transportation.

[0093] Example 3

[0094] A method for producing low-temperature refined marinated lard includes the following steps:

[0095] Step 1, Raw material selection:

[0096] The raw materials for lard are frozen lard or fresh lard, using fresh, clean and intact fat tissue from healthy pigs;

[0097] Step 2, Trimming and Cleaning:

[0098] After removing the fragments of muscle, blood, bones, organs, etc. that adhere to it, the dirt is washed away to obtain clean lard raw material;

[0099] Step 3, cut into pieces:

[0100] Cut the lard raw material into relatively uniform blocks and marinate it evenly.

[0101] Step 4, marinating:

[0102] Spread edible salt evenly on the surface of the lard raw material block, and then place it in a light-proof, airtight container to marinate;

[0103] Step 5, Vacuum refining:

[0104] The marinated lard raw material blocks are placed in a pressure vessel, liquid lard is added to form a solid-liquid mixture; then the vessel is sealed and vacuumed, heated with steam, and the pressure is released after refining.

[0105] Step 6, oil-sludge separation:

[0106] The refined solid-liquid mixture is added to an oil residue separator for oil residue separation. The liquid oil enters the oil tank, and the solid residue enters the oil press.

[0107] Step 7, Filtering:

[0108] After sedimentation and filtration, the liquid oil is stored in oil tanks and then bottled for preservation.

[0109] The adipose tissue in step 1 includes lard and fat.

[0110] The clean lard raw material in step 2 is dehydrated by air drying or squeezing.

[0111] The amount of edible salt used in step 4 is 12% of the mass of the lard raw material.

[0112] The pickling temperature in step 4 is 8°C, and the pickling time is 20 days.

[0113] In step 5, the vacuum degree is 0.096 MPa, the steam heating temperature is 110°C, and the time is 1-2 hours. During the steam heating process, stirring is also required, and the stirring speed is 80 r / min.

[0114] The pressed oil produced by pressing the solid residue in step 6 enters the oil tank and mixes with the liquid oil phase.

[0115] The pressed oil contains 7% solid impurities, and the residual oil content in the pressed oil cake is 8%.

[0116] The impurity content of the filtered liquid oil in step 7 is 0.15%.

[0117] The filling and storage conditions in step 7 are 2°C and protected from light during storage and transportation.

[0118] Comparison and detection

[0119] Figure 1 This study examines the changes in peroxide value of four products after storage: raw lard, cured lard, refined lard, and refined cured lard. The raw lard was fresh pork fat; the cured lard was fresh pork fat cured with salt; the refined lard was fresh pork fat refined under vacuum at low temperature; and the refined cured lard was the lard product prepared in Example 1. Hydroperoxides are the main initial products of auto-oxidation of oils and fats; therefore, detecting the peroxide value of these initial auto-oxidation products can serve as an oxidation index for the early stages of oil and fat oxidation.

[0120] All four products were stored at 25°C in unsealed containers, and peroxide values ​​were tested periodically. Figure 1It is clearly evident that the peroxide values ​​of all four products increased over time, with the raw lard showing the fastest increase, followed by cured lard, refined lard, and then Example 1. Numerically, the lard produced in Example 1 demonstrates significantly better control of peroxide value compared to the other methods, effectively extending its shelf life. This figure also effectively proves that the combination of salt curing and vacuum low-temperature refining technologies, through their synergistic effect, effectively controls the oxidation of lard, extending its shelf life, and achieving a longer shelf life than lard produced by either method alone.

[0121] Figure 2 This describes the changes in acid value of four products after storage: raw lard, cured lard, refined lard, and refined cured lard. The raw lard is fresh pork fat; the cured lard is fresh pork fat cured with salt; the refined lard is fresh pork fat refined under vacuum at low temperature; and the refined cured lard is the lard product prepared in Example 1. The hydroperoxides generated by the oxidation of fats are extremely unstable and further decompose to generate stimulating oxidation products (such as alcohols, aldehydes, acids, and other bifunctional oxides). Additionally, due to heating and the action of moisture in the food, the fats hydrolyze to generate free fatty acids and glycerol.

[0122] All four products were stored at 25°C in unsealed containers, and peroxide values ​​were tested periodically. Figure 1 It is clearly evident that the acid value of all four products increased over time, with the lard raw material showing the fastest increase. Example 1 exhibited the best stability. Numerically, the lard produced in Example 1 demonstrates significantly better acid value control than other methods, effectively extending its shelf life. This figure also effectively proves that the combination of salt curing and vacuum low-temperature refining technologies, through their synergistic effect, effectively controls the oxidation of lard, extending its shelf life to a longer duration than lard produced by either method alone.

[0123] In summary, the present invention has the following advantages:

[0124] 1. This invention solves the problem of easy deterioration of lard in the prior art. By combining pickling and vacuum refining, it significantly reduces the acid value and peroxide value of pickled lard products, effectively extending the shelf life of lard.

[0125] 2. The lard prepared by this invention has a special and good flavor and taste, which can significantly improve the sensory quality of the product.

[0126] 3. The process of this invention is highly controllable, which is conducive to mass production and industrialization while ensuring the quality of lard.

[0127] It is understood that the above detailed description of the present invention is for illustrative purposes only and is not intended to limit the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effects; as long as the usage requirements are met, they are all within the protection scope of the present invention.

Claims

1. A method of making a low-temperature refined cured lard characterized by, It comprises the following steps: Step 1, raw material selection: The lard raw material is fresh or fresh lard product, which is fresh, clean and intact fat tissue of healthy pigs; Step 2, trimming and cleaning: Remove the muscle, blood, bone, organ and other residues adhered to the surface, and flush away the dirt to obtain clean lard raw material; Step 3, cutting: Cut the lard raw material into blocks with uniform shape, which is beneficial to uniform curing; Step 4, curing: Uniformly apply edible salt on the surface of the lard raw material block, and then place it in a light-proof and airtight container for curing; the amount of edible salt used is 8-20% of the mass of the lard raw material; the curing temperature is 0-15℃, and the curing time is 15-30 days; Step 5, vacuum refining: Place the cured lard raw material block in a pressure container, add liquid lard to form a solid-liquid mixture, then seal and vacuumize, steam heat, release pressure after refining; the vacuum degree is 0.092-0.098 MPa, the steam heating temperature is 100-120℃, the time is 1-2h, and stirring is also required during the steam heating process, the stirring speed is 20-100r / min; Step 6, oil residue separation: Add the refined solid-liquid mixture to the oil residue separator for oil residue separation, the liquid oil enters the oil tank, and the solid residue enters the oil press; Step 7, filtration: After settling and filtering, the liquid oil is stored in an oil tank, then filled and stored.

2. A process for the preparation of low temperature refined cured lard according to claim 1, characterized in that: The fat tissue in step 1 includes lard and meat fat.

3. A process for the preparation of low temperature refined cured lard according to claim 1, characterized in that: The clean lard raw material in step 2 is treated by dehydration, and the dehydration method is natural air drying or extrusion dehydration.

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