A high-stability pectin-monascus pigment complex, method and application

Abstract

The present invention belongs to the technical field of nutritious food preparation and discloses a highly stable pectin-monascus pigment complex. The preparation method comprises the following steps: crushing; impurity removal; water extraction; alcohol precipitation; purification; pectinase hydrolysis; and free radical induction to prepare the pectin-monascus pigment complex. The pectin-monascus pigment complex helps improve the quality and color stability of ham sausage and can be used as a new food ingredient in the development of food or health products. The present invention can effectively improve the stability of the monascus pigment and reduce the damage to the monascus pigment color caused by environmental factors and other conditions. The dietary fiber used in the present invention comes from orange peel, a byproduct of agricultural product processing, which is widely available and low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of nutritious food preparation, and in particular to a high-stability pectin-monascus pigment complex, a method and an application thereof. Background Art

[0002] Monascus pigment is a natural food pigment produced by fermentation of Monascus purpureus. It boasts natural coloring, high safety, and multiple biological activities, including antibacterial and antiseptic properties, antioxidant, anti-cancer, lipid-lowering, anti-inflammatory, and immune-enhancing properties. It has been a hot topic in natural food pigment research and is widely used as a food additive in the food industry. However, despite its excellent stability under acidic, alkaline, and thermal conditions, monascus pigment undergoes degradation reactions caused by light absorption, significantly reducing its coloring properties and affecting the shelf life of foods, limiting its application in food.

[0003] To improve the stability of red rice pigments, methods are being developed to establish binary or multicomponent composite systems, such as pigment-protein-polysaccharide composite systems and W / O / W emulsion systems that encapsulate red rice pigments. However, despite the increasing number of multicomponent composites of red rice pigments, most still rely on amination reactions with amino acids, and the preparation systems are relatively complex.

[0004] Pectin, a naturally low-toxic polyanionic polysaccharide, is widely used to carry bioactive substances and is classified as generally recognized as safe by the U.S. Food and Drug Administration. Molecularly, pectin molecules possess a high degree of structural diversity; they are found in abundance in the fruits, roots, stems, and leaves of plants. According to a report released by the World Health Organization, China's citrus production accounts for approximately 28% of the global total, consistently ranking first in both citrus orchard area and production. Citrus peel, a byproduct of citrus processing, accounts for approximately 25%-40% of the fruit's weight and is in urgent need of development and utilization.

[0005] Through searching, we found the following patent publications related to the patent application of this invention:

[0006] 1. A food coloring-proteoglycan complex and its preparation method (CN 116686934B). This invention addresses the poor stability of food colorings such as monascus pigment by constructing a proteoglycan complex system. The complex includes soy protein isolate, carrageenan, transglutaminase, and potassium chloride. This system improves the light and heat stability of the food coloring and has broad application prospects in the food industry.

[0007] 2. A grapefruit peel pectin-anthocyanidin complex, its preparation method, and application (CN116686989A). This invention comprises mixing an aqueous grapefruit peel pectin solution with an aqueous anthocyanidin solution, ultrasonically treating the mixed solution, and drying it to obtain the grapefruit peel pectin-anthocyanidin complex. The pH of the aqueous anthocyanidin solution is anywhere from 1 to 3. This invention has applications in food, medicine, health products, and beverages. It addresses the problem that existing methods for improving anthocyanidin stability fail to achieve adequate anthocyanidin stabilization, and can significantly improve the heat resistance, alkali resistance, and digestion resistance of anthocyanidins.

[0008] 3. A method for preparing peach gum polysaccharide nanospheres loaded with fat-soluble pigments (CN110387142B). The invention comprises adding water-soluble peach gum polysaccharide, thioctic acid, and p-toluenesulfonic acid together to dimethyl sulfoxide. The resulting mixture is stirred and reacted at 80-110°C under a nitrogen atmosphere for 5-12 hours. The mixture is then dialyzed with deionized water for 24 hours and then centrifuged to collect the precipitate obtained by centrifugation. The collected centrifugal precipitate and a weight portion of fat-soluble pigment are added to an organic solvent, stirred for 10 minutes, and then dialyzed in deionized water for 24 hours to obtain peach gum polysaccharide nanospheres loaded with fat-soluble pigments. The nanospheres have good application prospects in the fields of functional foods and biomedicine.

[0009] 4. A red yeast rice health-care ham sausage and its production method (CN 1985670A). This invention combines fermented red yeast rice with pork, adds conventional seasoning powder, and then steams the sausage. The addition of red yeast rice provides excellent antioxidant and free radical protection, along with antibacterial, antiseptic, light-blocking, and flavor-enhancing properties. It nourishes the human body, strengthens the spleen and stomach, promotes blood circulation, and reduces blood lipids and cholesterol, making it a suitable tonic for all ages.

[0010] By comparison, the present patent application differs substantially from the aforementioned patent disclosures. Using fresh tangerine peel as raw material, the present invention employs a combination of weak acid extraction and enzymatic hydrolysis to prepare pectin with varying degrees of hydrolysis. Pectin-monascus pigment complexes are then prepared through physical mixing and free radical induction, resulting in a highly stable complex system. The pectin-monascus pigment complexes are then applied to the preparation of ham sausages, and the effects of the complexes on the texture and color of the sausages are evaluated, aiming to provide a theoretical basis for expanding new applications of monascus pigments. Summary of the Invention

[0011] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a highly stable pectin-monascus pigment complex, a preparation method and an application thereof.

[0012] The technical solution adopted by the present invention to solve its technical problem is:

[0013] A high-stability pectin-monascus pigment complex, the preparation method comprising the following steps:

[0014] (1) Preparation of pectin

[0015] 1) Preparation of orange peel pectin by acid extraction

[0016] Fresh orange peel is dried and crushed, and then the powder is taken, and anhydrous ethanol is added in an amount three times the volume of the powder, and the mixture is stirred at room temperature for 3 to 6 hours, centrifuged at 4000 r / min for 20 to 30 minutes, the supernatant is discarded, and the mixture is dried at 45°C to remove pigments, essential oils, and esters of the orange peel; distilled water is used as the extraction liquid, with a solid-liquid ratio of g:mL of 1:20, and citric acid is used to adjust the pH to 2. After extraction at 90°C for 2 hours, the mixture is centrifuged at 4000 r / min for 20 to 30 minutes, the supernatant is collected, and vacuum concentrated at 60°C to 1 / 5 of the original volume, and anhydrous ethanol is added to adjust the alcohol content to 62%-65%. The mixture is allowed to stand at 4°C overnight, and centrifuged again at 4000 r / min for 30 minutes to collect the precipitate; the mixture is re-dissolved in 60°C hot water, cooled to room temperature, poured into a petri dish, pre-cooled at -80°C for 2 hours, and dried in a vacuum freeze dryer at -50°C and a vacuum degree of 40 Pa for 24 hours to obtain crude orange peel pectin;

[0017] 2) Purification of orange peel pectin

[0018] The protein in crude orange peel pectin was removed by the Sevage method. The operation steps were as follows: a 10 mg / mL orange peel pectin aqueous solution was prepared, a 25% volume concentration of Sevage reagent was added, i.e., a mixture of chloroform and n-butanol in a volume ratio of 4:1, the mixture was shaken vigorously for 15 minutes, the stratification was allowed to stand, the lower organic phase and the middle protein were removed, and the steps were repeated until the white suspension in the middle disappeared; the upper aqueous phase was collected, anhydrous ethanol was added to make the alcohol content 62%-65%, the mixture was allowed to stand at 4°C overnight, centrifuged at 4000 r / min for 30 minutes, and the precipitate was collected; after the precipitate was redissolved with 60°C hot water, the redissolved solution was placed in a 3500Da dialysis bag and dialyzed in distilled water for 48 hours, with the water being replaced every 4 hours; finally, the dialyzate was pre-cooled at -80°C for 2 hours, and dried in a vacuum freeze dryer at -50°C and a vacuum degree of 40Pa for 24 hours to obtain orange peel pectin. pectin, referred to as O), stored in a drying dish for later use;

[0019] 3) Enzymatic hydrolysis and enrichment of pectin

[0020] Enzymatic hydrolysis of pectin: Orange peel pectin was enzymatically hydrolyzed to a pectin concentration of 10.0 mg / mL, and 0.05 mg / mL of pectinase was added. The temperature was 50°C, the treatment was performed for 15 min, and the enzymatic hydrolysis for 15 min was performed. The orange peel pectin O15 was obtained by freeze-drying.

[0021] (2) Preparation of pectin and monascus pigment complex

[0022] 1) Prepare a 10.0 mg / mL aqueous solution of orange peel pectin O15, which has been enzymatically hydrolyzed for 15 min, and heat at 60°C with stirring until completely dissolved;

[0023] 2) Add 1 mol / L H2O2 aqueous solution and Vc, and shake at 40°C for 30 minutes;

[0024] 3) Add red yeast rice pigment to the reaction flask and stir in the dark at room temperature for 24 h;

[0025] 4) The resulting solution was dialyzed using a 3500 Da dialysis bag and soaked in distilled water for 48 hours to remove unreacted pigment. The retained solution was lyophilized to obtain a free radical-inducing complex O15-FR of pectin and monascus pigment after enzymatic hydrolysis for 15 minutes, which is a highly stable pectin-monascus pigment complex;

[0026] The ratio of orange peel pectin O15 aqueous solution: 1 mol / L H2O2 aqueous solution: Vc: red yeast rice pigment is 10:0.2:10.8:12 in mL:mL:mg:mg.

[0027] Furthermore, the powder in step (1)1) is 60 mesh.

[0028] The application of the high-stability pectin-monascus pigment complex as described above in the preparation of ham sausage.

[0029] The method for preparing ham sausage using the high-stability pectin-monascus pigment complex comprises the following steps:

[0030] a. After washing the pork, remove the fascia, grind in a meat grinder for 10-15min, add 135 parts by weight of pork, 2-3.5 parts by weight of pectin red yeast rice complex O15-FR, 30-40 parts by weight of sausage solid compound seasoning, stir well and place in a refrigerator at 4 ℃ for 2h, stirring occasionally halfway;

[0031] b. Wash the casings with clean water and soak them in onion, ginger and cooking wine for 2-3 hours;

[0032] c. Use a sausage stuffer and cut it into relatively even small sections with a thin thread;

[0033] d. Steam the ham in cold water for 30 minutes after boiling, then remove from the water.

[0034] After cooling, the ham is packaged using a vacuum packaging machine.

[0035] Furthermore, 135 parts by weight of pork, 2.5 parts by weight of pectin-red yeast compound O15-FR, and 33.5 parts by weight of sausage solid compound seasoning.

[0036] The advantages and positive effects achieved by the present invention are:

[0037] 1. The dietary fiber used in the present invention comes from tangerine peel, a byproduct of agricultural product processing. It is widely available and inexpensive. The tangerine peel pectin extracted from it is a low-ester pectin and a water-soluble dietary fiber. Due to its stability, water solubility, and viscosity, it is widely used in foods such as dairy products, beverages, and jams. However, its application in meat products such as ham is still insufficient. In addition, it helps lower blood cholesterol levels, helps reduce glucose uptake, promotes epithelial cell proliferation and differentiation, maintains the intestinal mucosal barrier, promotes the reproduction of beneficial bacteria, and maintains the balance of the intestinal microecological environment.

[0038] 2. The present invention uses not a single red yeast rice pigment, but a composite pigment specifically embedded in polysaccharide macromolecules. This effectively improves the change in the color group of the red yeast rice pigment under light conditions, inhibits color loss, effectively improves the stability of the red yeast rice pigment, and reduces the damage to the red yeast rice pigment caused by environmental factors and other conditions. This composite can be used as a new food ingredient in the development of food or health products.

[0039] 3. The present invention utilizes a tangerine peel pectin-embedded monascus pigment composite to prepare ham sausage, which helps improve the quality and color stability of the ham sausage, optimizes the product's sensory qualities, enhances its storage stability, and simultaneously imparts safety and nutritional benefits to the ham sausage, avoiding the potential risks of artificial pigments. Furthermore, the present invention offers low cost and a wide range of sources, making it of great significance for the development of novel dietary fiber products and the value-added application of agricultural and sideline products.

[0040] 4. The present invention uses fresh orange peel as raw material, adopts weak acid extraction combined with enzymatic hydrolysis to prepare pectin with different degrees of enzymatic hydrolysis, prepares pectin-monascus pigment complex by physical mixing and free radical induction, screens out a highly stable complex system, and applies the pectin-monascus pigment complex to the preparation process of ham sausage to improve the quality of ham sausage. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The freeze-dried image of the orange peel pectin-monascus pigment complex of the present invention; wherein, a: free radical induction group; b: physical mixing group; c: blank group;

[0042] Figure 2 This is a photo of the ham sausage of the present invention;

[0043] Figure 3 This is a process flow chart for preparing the ham sausage of the present invention;

[0044] Figure 4The full wavelength scanning diagram of the pectin and monascus pigment complex of the present invention; wherein, O-PM: physical mixture of unhydrolyzed tangerine peel pectin and monascus pigment; O-FR: free radical-inducing complex of unhydrolyzed tangerine peel pectin and monascus pigment; O15-PM: physical mixture of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 15 minutes; O15-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 15 minutes; O30-PM: physical mixture of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 30 minutes; O30-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 30 minutes; R: monascus pigment;

[0045] Figure 5 This is a colorimetric diagram of the pectin and monascus pigment complex of the present invention; where O-PM: physical mixture of unhydrolyzed tangerine peel pectin and monascus pigment; O-FR: free radical-inducing complex of unhydrolyzed tangerine peel pectin and monascus pigment; O15-PM: physical mixture of tangerine peel pectin and monascus pigment after 15 minutes of hydrolysis; O15-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after 15 minutes of hydrolysis; O30-PM: physical mixture of tangerine peel pectin and monascus pigment after 30 minutes of hydrolysis; O30-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after 30 minutes of hydrolysis. Different letters indicate significant differences between samples, p < 0.05.

[0046] Figure 6 Figure 1 shows the effect of temperature on the pigment preservation rate of the pectin-monascus pigment complex of the present invention (a: 90°C; b: 70°C; c: 50°C; d: 30°C). Here, O-PM: physical mixture of unenzymatically hydrolyzed tangerine peel pectin and monascus pigment; O-FR: free radical-inducing complex of unenzymatically hydrolyzed tangerine peel pectin and monascus pigment; O15-PM: physical mixture of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 15 minutes; O15-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 15 minutes; O30-PM: physical mixture of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 30 minutes; O30-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 30 minutes; R: monascus pigment. Different letters indicate significant differences between samples at the same treatment time, p < 0.05.

[0047] Figure 7This figure shows the effect of pH on the pigment preservation rate of the pectin-monascus pigment complex of the present invention. Here, O-PM: physical mixture of undigested tangerine peel pectin and monascus pigment; O-FR: free radical-inducing complex of undigested tangerine peel pectin and monascus pigment; O15-PM: physical mixture of tangerine peel pectin and monascus pigment after 15 minutes of enzymatic hydrolysis; O15-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after 15 minutes of enzymatic hydrolysis; O30-PM: physical mixture of tangerine peel pectin and monascus pigment after 30 minutes of enzymatic hydrolysis; O30-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after 30 minutes of enzymatic hydrolysis; R: monascus pigment. Different letters indicate significant differences between samples at different pH values ​​compared to a neutral environment, p < 0.05.

[0048] Figure 8 Figure 1 shows the effect of different light conditions on the pigment preservation rate of the pectin-monascus pigment complex in the present invention (a: UV light; b: dark); where: O-PM: physical mixture of undigested tangerine peel pectin and monascus pigment; O-FR: free radical-inducing complex of undigested tangerine peel pectin and monascus pigment; O15-PM: physical mixture of tangerine peel pectin and monascus pigment after 15 min of enzymatic hydrolysis; O15-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after 15 min of enzymatic hydrolysis; O30-PM: physical mixture of tangerine peel pectin and monascus pigment after 30 min of enzymatic hydrolysis; O30-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after 30 min of enzymatic hydrolysis; R: monascus pigment. Different letters indicate significant differences between samples at the same time, p < 0.05.

[0049] Figure 9 This is a product photo of a solid composite seasoning for sausages used in the present invention. DETAILED DESCRIPTION

[0050] The present invention will be further described below with reference to the following examples. The following examples are descriptive rather than restrictive, and the scope of protection of the present invention cannot be limited by the following examples.

[0051] The various experimental operations involved in the specific embodiments are all routine techniques in the field. For parts not specifically annotated in this document, ordinary technicians in this field can refer to various commonly used reference books, scientific literature or related instructions, manuals, etc. before the filing date of this invention to implement them.

[0052] A high-stability pectin-monascus pigment complex, the preparation method comprising the following steps:

[0053] (1) Preparation of pectin

[0054] 1) Preparation of orange peel pectin by acid extraction

[0055] Fresh orange peel is dried and crushed, and then the powder is taken, and anhydrous ethanol is added in an amount three times the volume of the powder, and the mixture is stirred at room temperature for 3 to 6 hours, centrifuged at 4000 r / min for 20 to 30 minutes, the supernatant is discarded, and the mixture is dried at 45°C to remove pigments, essential oils, and esters of the orange peel; distilled water is used as the extraction liquid, with a solid-liquid ratio of g:mL of 1:20, and citric acid is used to adjust the pH to 2. After extraction at 90°C for 2 hours, the mixture is centrifuged at 4000 r / min for 20 to 30 minutes, the supernatant is collected, and vacuum concentrated at 60°C to 1 / 5 of the original volume, and anhydrous ethanol is added to adjust the alcohol content to 62%-65%. The mixture is allowed to stand at 4°C overnight, and centrifuged again at 4000 r / min for 30 minutes to collect the precipitate; the mixture is re-dissolved in 60°C hot water, cooled to room temperature, poured into a petri dish, pre-cooled at -80°C for 2 hours, and dried in a vacuum freeze dryer at -50°C and a vacuum degree of 40 Pa for 24 hours to obtain crude orange peel pectin;

[0056] 2) Purification of orange peel pectin

[0057] The protein in crude orange peel pectin was removed by the Sevage method. The operation steps were as follows: a 10 mg / mL orange peel pectin aqueous solution was prepared, a 25% volume concentration of Sevage reagent was added, i.e., a mixture of chloroform and n-butanol in a volume ratio of 4:1, the mixture was shaken vigorously for 15 minutes, the stratification was allowed to stand, the lower organic phase and the middle protein were removed, and the steps were repeated until the white suspension in the middle disappeared; the upper aqueous phase was collected, anhydrous ethanol was added to make the alcohol content 62%-65%, the mixture was allowed to stand at 4°C overnight, centrifuged at 4000 r / min for 30 minutes, and the precipitate was collected; after the precipitate was redissolved with 60°C hot water, the redissolved solution was placed in a 3500Da dialysis bag and dialyzed in distilled water for 48 hours, with the water being replaced every 4 hours; finally, the dialyzate was pre-cooled at -80°C for 2 hours, and dried in a vacuum freeze dryer at -50°C and a vacuum degree of 40Pa for 24 hours to obtain orange peel pectin. pectin, referred to as O), stored in a drying dish for later use;

[0058] 3) Enzymatic hydrolysis and enrichment of pectin

[0059] Enzymatic hydrolysis of pectin: Orange peel pectin was enzymatically hydrolyzed to a pectin concentration of 10.0 mg / mL, and 0.05 mg / mL of pectinase was added. The temperature was 50°C, the treatment was performed for 15 min, and the enzymatic hydrolysis for 15 min was performed. The orange peel pectin O15 was obtained by freeze-drying.

[0060] (2) Preparation of pectin and monascus pigment complex

[0061] 1) Prepare a 10.0 mg / mL aqueous solution of orange peel pectin O15, which has been enzymatically hydrolyzed for 15 min, and heat at 60°C with stirring until completely dissolved;

[0062] 2) Add 1 mol / L H2O2 aqueous solution and Vc, and shake at 40°C for 30 minutes;

[0063] 3) Add red yeast rice pigment to the reaction flask and stir in the dark at room temperature for 24 h;

[0064] 4) The resulting solution was dialyzed using a 3500 Da dialysis bag and soaked in distilled water for 48 hours to remove unreacted pigment. The retained solution was lyophilized to obtain a free radical-inducing complex O15-FR of pectin and monascus pigment after enzymatic hydrolysis for 15 minutes, which is a highly stable pectin-monascus pigment complex;

[0065] The ratio of orange peel pectin O15 aqueous solution: 1 mol / L H2O2 aqueous solution: Vc: red yeast rice pigment is 10:0.2:10.8:12 in mL:mL:mg:mg.

[0066] Preferably, the powder in step (1)1) is 60 mesh.

[0067] The application of the high-stability pectin-monascus pigment complex as described above in the preparation of ham sausage.

[0068] The method for preparing ham sausage using the high-stability pectin-monascus pigment complex comprises the following steps:

[0069] e. After washing the pork, remove the fascia, grind in a meat grinder for 10-15min, add 135 parts by weight of pork, 2-3.5 parts by weight of pectin red yeast rice complex O15-FR, 30-40 parts by weight of sausage solid compound seasoning, stir well and place in a refrigerator at 4 ℃ for 2h, stirring occasionally halfway;

[0070] f. Wash the casings with clean water and soak them in onion, ginger and cooking wine for 2-3 hours;

[0071] g. Use a sausage stuffer and cut it into relatively even small sections with a thin thread;

[0072] h. Steam the ham in cold water for 30 minutes after boiling, then remove from the water.

[0073] After cooling, the ham is packaged using a vacuum packaging machine.

[0074] Preferably, 135 parts by weight of pork, 2.5 parts by weight of pectin-red yeast rice complex O15-FR, and 33.5 parts by weight of sausage solid compound seasoning are used.

[0075] Specifically, the relevant preparation and detection are as follows:

[0076] Example 1:

[0077] A high-stability pectin-monascus pigment complex, the preparation method comprising the following steps:

[0078] (1) Preparation of pectin-monascus pigment complex

[0079] a. Crushing: Fresh orange peel was dried in a blast drying oven at 50°C and ultrafinely ground, passed through a 60-mesh sieve;

[0080] b. Impurity removal: Add three times the volume of anhydrous ethanol and stir at room temperature for 3 hours. Centrifuge at 4000 rpm for 20 minutes. Repeat three times to remove pigments and lipids. Volatilize the remaining ethanol in a fume hood.

[0081] c. Water extraction: Water extraction was performed at a material-liquid ratio of 1:20. Distilled water was added to the dried and ground raw material, and the pH was adjusted to 2 with citric acid. The mixture was heated at 90°C with stirring for 2 hours, and centrifuged at 4000 rpm for 20 minutes. The supernatant was collected and the mixture was repeated three times. The supernatants were combined and then rotary evaporated.

[0082] d. Alcohol precipitation: Anhydrous ethanol was added to the aqueous extract to a final concentration of 62-65%, and the mixture was incubated at 4°C overnight. The precipitate was centrifuged at 4000 rpm for 30 minutes, and the solution was reconstituted in 60°C hot water and cooled to room temperature. The solution was poured into a petri dish, pre-cooled at -80°C for 2 hours, and dried in a vacuum freeze dryer at -50°C and a vacuum degree of 40 Pa for 24 hours to obtain crude orange peel pectin.

[0083] e. Purification: Protein was removed from crude tangerine peel pectin using the Sevage method as follows: a 10 mg / mL aqueous solution of tangerine peel pectin was prepared, and a 25% by volume concentration of Sevage reagent (a mixture of chloroform and n-butanol in a volume ratio of 4:1) was added. The solution was shaken vigorously for 15 minutes, allowed to stand to separate, and the lower organic phase and the middle protein phase were removed. This step was repeated until the white suspension in the middle layer disappeared. The upper aqueous phase was collected and anhydrous ethanol was added to a concentration of 62%-65% alcohol. The solution was allowed to stand overnight at 4°C, and centrifuged at 4000 r / min for 30 minutes to collect the precipitate. The precipitate was reconstituted with 60°C hot water, and the reconstituted solution was placed in a 3500 Da dialysis bag and dialyzed against distilled water for 48 hours, with the water replaced every 4 hours. Finally, the dialysate was pre-cooled at -80°C for 2 h, and dried in a vacuum freeze dryer at -50°C and a vacuum degree of 40 Pa for 24 h to obtain orange peel pectin (O), which was stored in a drying dish for later use.

[0084] f. Enzymatic hydrolysis of pectin with different molecular structures: The orange peel pectin described in e was hydrolyzed to prepare a pectin concentration of 10.0 mg / mL, 0.05 mg / mL of pectinase, and a temperature of 50°C for 15 min and 30 min, respectively, and freeze-dried to obtain orange peel pectin O15 and orange peel pectin O30 hydrolyzed for 15 min and 30 min, respectively;

[0085] g. Complex preparation: Prepare a 10 mg / mL pectin solution and heat at 60°C with stirring until completely dissolved. The complex preparation groups are as follows:

[0086] 1) Blank group: Tangerine peel pectin without adding pigment, H2O2 and Vc was used as blank control, including original tangerine peel pectin (O), tangerine peel pectin enzymatically hydrolyzed for 15 minutes (O15) and tangerine peel pectin enzymatically hydrolyzed for 30 minutes (O30).

[0087] 2) Physical Mixture (PM): ① Prepare 10 mL of 10.0 mg / mL aqueous solution of pectin with different degrees of enzymatic hydrolysis, heat and stir at 60°C until completely dissolved; ② Stir at 40°C for 30 min; ③ Add 12 mg of monascus pigment to the reaction flask, stir in the dark at room temperature for 24 h; ④ Dialyze the resulting solution using a 3500 Da dialysis bag and soak in distilled water for 48 h to remove unreacted pigment, and lyophilize the retained solution to obtain a physical mixture of original pectin (i.e., original orange peel pectin (O)) and monascus pigment (O-PM), a physical mixture of pectin enzymatically hydrolyzed for 15 min and monascus pigment (O15-PM), and a physical mixture of pectin enzymatically hydrolyzed for 30 min and monascus pigment (O30-PM).

[0088] 3) Free radical induction group (FR): ① Prepare 10 mL of 10.0 mg / mL aqueous solution of pectin with different degrees of enzymatic hydrolysis, heat and stir at 60°C until completely dissolved; ② Add 0.2 mL of 1 mol / L H2O2 aqueous solution and 10.8 mg of Vc, and react at 40°C with shaking for 30 min; ③ Add 12 mg of monascus pigment to the reaction flask, stir in the dark at room temperature for 24 h; ④ The resulting solution was dialyzed using a 3500 Da dialysis bag and soaked in distilled water for 48 h to remove unreacted pigment, and the retained solution was lyophilized to obtain the free radical induction complex of original pectin and monascus pigment (O-FR), the free radical induction complex of pectin and monascus pigment after enzymatic hydrolysis for 15 min (O15-FR), and the free radical induction complex of pectin and monascus pigment after enzymatic hydrolysis for 30 min (O30-FR).

[0089] Example 2: Characterization of Pectin-Monascus Pigment Complex

[0090] Characterization of the above complex:

[0091] a. UV full wavelength scan

[0092] Prepare a 1 mg / mL pectin-monascus pigment aqueous solution and allow the solution to stabilize for 30 minutes at room temperature, protected from light. Then, scan the solution using an ultraviolet spectrophotometer over the entire wavelength range of 400-600 nm, using deionized water as a blank. Graph the absorption spectrum and determine the maximum absorption wavelength of the sample.

[0093] b. Determination of color value

[0094] Prepare a 1 mg / mL aqueous solution of pectin-monascus pigment complex, add it to a quartz cuvette, and measure its absorbance at 385 nm (red pigment), 475 nm (orange pigment), 505 nm (yellow pigment) and 410 nm (total pigment). Use distilled water as a blank and set the absorbance to be between 0.2 and 0.8. Calculate the color value according to formula (1-1).

[0095]

[0096] Where: S is color value; A is absorbance; V is volume of distilled water (mL); m is mass (g); n is dilution factor.

[0097] c. Chromaticity determination: The brightness (L), red-green (a*), yellow-blue (b*), and color difference (ΔE) values ​​of the pectin-monascus pigment complex were measured using a colorimeter and compared with the monascus pigment solution.

[0098] Example 3: Stability of Pectin-Monascus Pigment Complex

[0099] Characterize the stability of the above complex:

[0100] a. Determination of the correlation between concentration and absorbance of the pectin-monascus pigment complex: Prepare sample solutions with gradient concentrations (0, 0.2, 0.4, 0.6, 0.8, and 1 mg / mL) and measure the absorbance at the maximum visible absorption wavelength of the complex. Construct a correlation equation between concentration and absorbance, and calculate the correlation coefficient.

[0101] b. Effect of different temperatures on the stability of pectin-monascus pigment complex

[0102] Sample solutions of equal concentrations were prepared and treated in the dark at 30, 50, 70, and 90°C for 5 hours. Samples were taken every hour and the absorbance at the wavelength of maximum absorption was measured using a microplate reader. The pigment preservation rate was calculated according to formula (1-2). The effect of pectin on the stability of red yeast rice pigment was evaluated by analyzing the change in pigment preservation rate over treatment time. Three replicates were prepared for each sample, and a control group containing red yeast rice pigment at an equal concentration was used.

[0103] c. Effect of different pH on the stability of pectin-monascus pigment complex

[0104] Different aqueous solutions with pH values ​​of 1, 3, 5, 7, 9, 11, and 13 were prepared using 1 mol / L HCl solution and 1 mol / L NaOH solution. 1 mg of the complex was dissolved in 1 mL of solutions with different pH values ​​and allowed to stand for 30 minutes in the dark. The absorbance was measured at the maximum absorption wavelength, and the absorbance value of the neutral aqueous solution (pH = 7) was used as the standard. The pigment preservation rate was calculated according to formula (1-2). The effect of pectin on the stability of red yeast rice pigment was evaluated by the change of pigment preservation rate with pH. Three parallel samples were set for each sample, and red yeast rice pigment of equal concentration was used as the control group.

[0105] d. Effect of different light exposures on the stability of pectin-monascus pigment complex

[0106] Prepare a sample solution of equal concentration and place it in a light incubator at room temperature for ultraviolet light and dark treatment for 5 hours. The ultraviolet wavelength is 254nm, the light intensity is 8W, and the light distance is 35cm. Sampling is taken every hour, and the change in absorbance is measured at the maximum absorption wavelength using a microplate reader. The pigment preservation rate is calculated according to formula (1-2). Based on the change in pigment preservation rate over treatment time, the effect of pectin on the stability of red yeast rice pigment is evaluated. Three parallels are set for each sample to ensure the authenticity of the data. At the same time, red yeast rice pigment with equal concentration is used as the control group.

[0107] e. Determination of pigment preservation rate

[0108] The absorbance was measured at the maximum absorption wavelength, and the pigment preservation rate W was calculated according to formula (1-2).

[0109]

[0110] Where: W: pigment preservation rate; A1: average Abs value of sample after treatment; A2: average Abs value of sample before treatment.

[0111] Example 4:

[0112] Taking into account factors such as light, heat and pH, the O15-FR (i.e., the free radical-inducing complex of pectin and red yeast rice pigment (O15-FR)) with the best stability was selected to prepare ham sausage. The method for preparing ham sausage using the above-mentioned complex can be as follows: Figure 3 As shown, the following steps are included:

[0113] i. After washing the pork, remove the fascia, grind it in a meat grinder for 10-15min, add 135 parts by weight of pork, 2.5 parts by weight of pectin red yeast rice complex O15-FR, and sausage solid compound seasoning (seasonings known in the art can be commercially available products, such as a product photo picture can be as shown Figure 9 33.5 parts by weight of the mixture were stirred evenly and placed in a refrigerator at 4°C for 2 hours, with occasional stirring. In the blank group, red yeast rice pigment was used instead of O15-FR.

[0114] j. Wash the casings with clean water and soak them in onion, ginger and cooking wine for 2-3 hours;

[0115] k. Use a sausage stuffer and cut it into relatively even small sections with a thin thread;

[0116] l. Put the ham sausage into cold water and steam it. After it boils for 30 minutes, take it out.

[0117] After cooling, the ham is packaged using a vacuum packaging machine.

[0118] The preparation method of O15-FR is the same as the preparation method of the free radical-inducing complex (O15-FR) of pectin and monascus pigment enzymatically hydrolyzed for 15 minutes in Example 1.

[0119] Example 5:

[0120] The texture and color difference of the ham prepared in Example 4 were measured:

[0121] 1) Texture Measurement: Remove the sausage from a 4°C refrigerator and place it at room temperature for 90 minutes. After removing the casing, cut it into approximately 2 cm segments. The test parameters were set as follows: test speed 2 mm / s, compression ratio 40%, interval between compressions 2 seconds, activation force 5 g, probe type P / 36R. Hardness, springiness, cohesion, and chewiness were used as test indicators. Texture parameters were as follows: Hardness: the maximum peak value during the first compression; Springiness: the ratio of the second to the first puncture height measurement; Cohesion: the ratio of the area during the contraction phase of the first compression to the area during the compression phase; Chewiness was calculated according to formula (1-3).

[0122] Chewing property = gel property × elasticity (1-3)

[0123] 2) Determination of color difference of ham sausage within 30 days

[0124] The color difference (ΔE) value of the ham sausage was detected by a colorimeter and compared with the ham sausage with only red yeast rice pigment added.

[0125] The relevant detection of the present invention is as follows:

[0126] 1. Characterization of Pectin-Monascus Complex

[0127] 1. Full wavelength scanning

[0128] The results are as follows Figure 4As shown in the figure, the maximum absorption wavelengths of each pectin-monascus pigment complex occur between 494 and 496 nm, all higher than those of the monascus pigment complex. This indicates that the absorption spectrum of the complex has shifted its maximum absorption peak wavelength toward longer wavelengths in the visible light band, a phenomenon known as a red shift, also known as the "Doppler effect." This is likely due to structural changes in the complex, conjugation between the pectin and the monascus pigment, the introduction of auxochrome groups or auxochrome bands, which cause changes in the UV spectrum, enhance the pigment's staining effect, and promote the color development of the monascus pigment. This red shift also demonstrates that pectin and monascus pigment bind to a certain extent. Furthermore, the maximum absorption wavelength of the complex varies with the degree of enzymatic hydrolysis of the pectin. The lower the degree of enzymatic hydrolysis, the greater the red shift.

[0129] 2. Determination of color value

[0130] The results are as follows Figure 5 As shown in the figure, it can be seen that color value is an indicator of color depth or color intensity, which is closely related to the pigment content. Therefore, it can reflect the degree of combination of pectin and red yeast rice pigment to a certain extent. Figure 5 As shown, among the pectin-monascus pigment complexes, O30-PM has the highest red pigment color value, orange pigment color value, yellow pigment color value, and total pigment color value, which are 572.8±26.3, 930.0±61.57, 992.5±75.1, and 774.2±60.8 U / g, respectively, indicating that it has the best binding effect with monascus pigment. The various complexes are ranked from high to low according to total color value:

[0131] The order of O30-PM>O-PM>O15-PM>O-FR>O15-FR>O30-FR indicates that the physical mixing group has a better binding effect than the free radical induction group. In particular, the total color value of O30-PM is 2.1 times that of O30-FR.

[0132] Significance analysis revealed differences in red pigment valence, orange pigment valence, yellow pigment valence, and total pigment among the composites. Specifically, the color valence of O30-PM was significantly higher (p < 0.05) than that of the other treatments. There were no significant differences in color valence between O-PM, O-FR, and O15-PM (p > 0.05), nor between O15-FR and O30-FR (p > 0.05). Therefore, the binding effect of pectin and monascus pigment differed depending on the enzymatic hydrolysis conditions, with physical mixing promoting binding more effectively than free radical induction. Furthermore, the longer the enzymatic hydrolysis time, the greater the effect of the composite color valence on the composite. The composite effect of pectin treated with monascus pigment was largely unaffected by the composite method.

[0133] 3. Stability

[0134] (1) Correlation analysis between the concentration and absorbance of pectin-monascus pigment complex

[0135] According to the Lambert-Beer law, the relationship between the concentration of red koji pigment and pectin-red koji pigment complex and absorbance was determined. As shown in Table 1, the regression equation of red koji pigment is y=4.022x+0.0539(R 2 =0.9988), indicating that there is a good linear relationship between pigment concentration and absorbance. At the same time, the concentration of pectin-monascus pigment complex is also positively correlated with absorbance, and R 2 The results were all greater than 0.99. Therefore, changes in absorbance can directly reflect changes in the complex. Based on this, the effects of different temperature, pH, and light conditions on the complex were subsequently studied.

[0136] Table 1 Correlation between the concentration and absorbance of monascus pigment and pectin-monascus pigment complex

[0137]

[0138] Note: O-PM: physical mixture of unhydrolyzed tangerine peel pectin and monascus pigment; O-FR: free radical-inducing complex of unhydrolyzed tangerine peel pectin and monascus pigment; O15-PM: physical mixture of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 15 min; O15-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 15 min; O30-PM: physical mixture of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 30 min; O30-FR: free radical-inducing complex of tangerine peel pectin and monascus pigment after enzymatic hydrolysis for 30 min; R: monascus pigment.

[0139] (2) Effect of temperature on the stability of pectin-monascus pigment complex

[0140] The samples were treated in the dark at 30, 50, 70 and 90℃, and the changes in the pigment preservation rate were as follows: Figure 6 As shown. The results show that as the treatment time increases, the pigment preservation rate continues to decline. At the same time, the temperature plays a crucial role in the change of the pigment preservation rate. Low temperature has little effect on the pigment preservation rate, while high temperature treatment will significantly (p<0.05) reduce the pigment preservation rate, indicating that red yeast rice pigment has poor tolerance to high temperature. Specifically, after 5 hours of heat treatment of red yeast rice pigment, when the temperature is 30℃, the pigment preservation rate is 95.87%, which is only a decrease of 4.13%; at 70℃, the pigment preservation rate is 80.76%, which is a decrease of 19.24%, which is 4.7 times the decrease at 30℃; and after treatment at 90℃ for 5 hours, its pigment preservation rate is 54.35%, which is a decrease of 45.65%, which is more than 11 times the decrease at 30℃.

[0141] The results are as follows Figure 6As shown in the results, there was no significant difference in pigment preservation between the pectin-monascus pigment complexes after treatment at 30°C (p>0.05). However, after treatment at 90°C, the pigment preservation rates of O15-FR and O30-PM decreased more gradually, and their thermal stability was significantly improved. This indicates that O15-FR and O30-PM can effectively protect the pigment and inhibit fading. Specifically, after treatment at 90°C for 5 hours, the pigment preservation rate of O30-PM increased by 8.59% compared to R, which will effectively improve the fading problem of monascus pigment during its application in the food industry. In addition, not all pectin-monascus pigment complexes can increase the heat resistance of the pigment. For example, the pigment preservation rate of O-FR has no significant difference from that of monascus pigment at any temperature (p>0.05), indicating that the heat resistance of the two is not much different; after O15-PM and O30-FR were treated at 90℃ for 5h, the pigment preservation rate decreased more, only 30.25% and 34.98%, which was significantly lower than that of monascus pigment (p<0.05).

[0142] (3) Effect of pH on the stability of pectin-monascus pigment complex

[0143] Under different pH conditions, the pigment preservation rate of each substance is different. Studies have shown that the pigment preservation rate of red yeast rice pigment in neutral solution is better. Therefore, the absorbance at pH = 7 is used as the standard to calculate the pigment preservation rate of samples in different pH solutions to explore the effect of pH on the stability of pectin-red yeast rice pigment complex. Figure 7 It can be seen that when pH is 5≤≤9, the pigment preservation effect of the red yeast rice pigment group is better, and the pigment preservation rate exceeds 97%, indicating that the pigment is relatively stable in weak acid, weak base and neutral environments. When pH <5, the pigment preservation rate decreases with the decrease of pH, especially when pH = 1, the pigment preservation rate of R is 61.8%, indicating that the pigment is poorly stable in a strong acid environment, which may be attributed to the H in the solution. + It accelerates the interaction between water molecules and pigment molecules, thereby affecting the charge of the chromophore in the pigment structure, causing the key chemical groups to hydrolyze and precipitate; when pH>9, the pigment preservation rate decreases continuously with the increase of pH. When pH=13, the pigment preservation rate of R is 52.8%, which is lower than the pigment preservation rate in a strong acid environment, indicating that the pigment has poor stability in a strong alkaline environment and is inferior to that in an acidic environment, which is mainly affected by the red pigment in the pigment.

[0144] Compared with R, pectin can provide some protection for the pigment. When pH is 5 ≤ ​​≤ 9, the pigment preservation rates of O15-FR and O30-PM exceed 98%, significantly higher than those of R (p < 0.05). At pH = 1, all complexes exhibited higher pigment preservation rates than R, with O-PM achieving a high preservation rate of 81.8%, a 20% increase compared to R. This suggests that pectin effectively protects the red yeast rice pigment in a highly acidic environment. At pH = 13, the pigment preservation rates of all complexes also exceeded those of R, with O30-FR remaining close to 100%, indicating that pectin enhances the pigment's alkali resistance. Different complexes exhibit varying pigment preservation effects. Furthermore, pectin-red yeast rice pigment complexes with low enzymatic hydrolysis degrees, such as O-PM, exhibit better acid resistance, while pectin-red yeast rice complexes with high enzymatic hydrolysis degrees, such as O30-PM, exhibit better alkali resistance. Therefore, the appropriate pectin-red yeast rice complex can be selected based on the specific application.

[0145] (4) Effect of light on the stability of pectin-monascus pigment complex

[0146] The samples were subjected to UV light protection treatment and the changes in pigment preservation rate were observed within 5 hours. Figure 8 When protected from light, the pigment preservation rate of R remained essentially unchanged, approaching 100%. Meanwhile, the pigment preservation rate of the pectin-monascus pigment complex was not significantly different from that of R (p>0.05), indicating that protection from light does not affect pigment stability. When exposed to UV light, the pigment preservation rate of each group decreased over time, indicating that pigment stability is affected by light exposure. This is primarily due to the susceptibility of monascus pigment to photodegradation under UV light. When the illumination time was less than 2 hours, the pigment preservation of each complex was superior to that of R, indicating that the complex effectively improved the stability of monascus pigment. When exposed to light for 5 hours, O-PM, O-FR, O15-PM, and O15-FR all significantly improved pigment stability (p<0.05). This may be because pectin, by blocking UV light, slows the pigment's decomposition due to the Norrish type I reaction and reduces the cleavage of aliphatic and amino acid side chains.

[0147] 2. Determination of Ham Sausage Index

[0148] During storage, the pigments in ham sausage are prone to photodegradation, which affects the shelf life. Therefore, considering factors such as light, heat and pH, O15-FR with the best stability was selected for use in ham sausage processing.

[0149] 1. Texture

[0150] Table 2 Analysis of ham sausage texture

[0151]

[0152] Note: R: Ham sausage with added monascus pigment; OR: Ham sausage with added O15-FR. Different letters indicate significant differences between samples, p < 0.05.

[0153] A texture analyzer was used to measure the hardness, elasticity, cohesion, and chewiness of the ham. The results are shown in Table 2. There was no significant difference in hardness and cohesion between O15-FR and R (p>0.05), but there was a significant difference in elasticity and chewiness (p<0.05). This may be because the addition of O15-FR increased the proportion of dietary fiber in the ham and reduced the relative content of meat, which weakened the gel structure formed by protein denaturation, resulting in a decrease in the hardness and elasticity of the ham. Studies have shown that the addition of hydrophilic colloids to ham will interact with proteins, increase the hardness of salt-soluble meat proteins, and improve the elasticity of meat products. This is different from the results of this experiment. It may be that the pectin in the complex is low-esterification pectin, and its gel properties are affected by calcium ion concentration and pH.

[0154] 2. Analysis of color difference changes of ham sausage within 30 days

[0155] Color, due to its intuitive nature, directly influences consumer preference. ΔE, representing the total color difference of a sample, is the primary indicator for measuring color change. The present invention simulated two storage conditions: room temperature with light and refrigerated storage at 4°C in the dark. The color difference of ham sausages was observed over a 30-day storage period. The results (Table 3) show that the color difference of ham sausages increased with increasing storage period. Under room temperature with light, the color difference of both the R and OR groups showed significant differences (p < 0.05) after 30 days of storage. However, the color difference of R (1.28 ± 0.18) was twice that of OR (0.64 ± 0.25). Under refrigerated storage in the dark, the color difference of OR did not show significant differences over the storage period (p > 0.05), while the color difference of R showed significant differences after 30 days of storage (p < 0.05). This indicates that OR is more stable than R under both simulated storage conditions, and the application of red yeast rice-pectin complexes can help improve the color stability of ham sausages.

[0156] Table 3 Results of color difference determination of ham sausage during 30-day storage period

[0157] ΔE OR-L RL OR-B RB 5 <![CDATA[0.27±0.09 a ]]> <![CDATA[0.41±0.08 ab ]]> <![CDATA[0.53±0.16 a ]]> <![CDATA[0.59±0.19 a <!-- 11 -->]]> 10 <![CDATA[0.42±0.15 ab ]]> <![CDATA[0.47±0.49 ab ]]> <![CDATA[0.62±0.38 a ]]> <![CDATA[0.66±0.30 a ]]> 15 <![CDATA[0.47±0.21 ab ]]> <![CDATA[0.58±0.10 abc ]]> <![CDATA[0.79±0.60 a ]]> <![CDATA[0.74±0.27 a ]]> 20 <![CDATA[0.56±0.18 abc ]]> <![CDATA[0.84±0.15 cd ]]> <![CDATA[0.90±0.50 a ]]> <![CDATA[0.84±0.26 a ]]> 25 <![CDATA[0.57±0.13 abc ]]> <![CDATA[0.93±0.18 d ]]> <![CDATA[0.92±0.45 a ]]> <![CDATA[0.86±0.61 a ]]> 30 <![CDATA[0.64±0.25 bcd ]]> <![CDATA[1.28±0.18 e ]]> <![CDATA[1.03±0.32 ab ]]> <![CDATA[1.17±0.41 b ]]>

[0158] Note: OR-L: Ham with pectin-monascus pigment complex O15-FR stored at room temperature under light conditions; RL: Ham with monascus pigment stored at room temperature under light conditions; OR-B: Ham with pectin-monascus pigment complex O15-FR stored refrigerated and protected from light; RB: Ham with monascus pigment stored refrigerated and protected from light. Different letters indicate significant differences between the same samples at different time periods, p < 0.05.

[0159] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A highly stable pectin-monascus pigment complex, characterized by: The preparation method comprises the following steps: (1) Preparation of pectin 1) Preparation of orange peel pectin by acid extraction Fresh orange peel is dried and crushed, and the powder is taken, and anhydrous ethanol with a volume three times that of the powder is added, and the mixture is stirred at room temperature for 3 to 6 hours, centrifuged at 4000 rpm for 20 to 30 minutes, and the supernatant is discarded. The mixture is then dried at 45°C to remove the pigment, essential oil and ester substances in the orange peel; The extract was extracted with distilled water at a solid-liquid ratio of 1:20 (g:mL). The pH was adjusted to 2 with citric acid. After extraction at 90°C for 2 hours, the extract was centrifuged at 4000 r / min for 20-30 minutes, and the supernatant was collected. The extract was vacuum concentrated at 60°C to 1 / 5 of the original volume, and then anhydrous ethanol was added to adjust the alcohol content to 62%-65%. The extract was allowed to stand at 4°C overnight, and centrifuged again at 4000 r / min for 30 minutes to collect the precipitate. The extract was re-dissolved in 60°C hot water and cooled to room temperature. The solution was poured into a petri dish, pre-cooled at -80°C for 2 hours, and dried in a vacuum freeze dryer at -50°C and a vacuum degree of 40 Pa for 24 hours to obtain crude orange peel pectin. 2) Purification of orange peel pectin The Sevage method was used to remove protein from crude pectin from orange peels. The steps were as follows: a 10 mg / mL aqueous solution of orange peel pectin was prepared, and a 25% volume concentration of Sevage reagent (a mixture of chloroform and n-butanol at a volume ratio of 4:1) was added. The solution was shaken vigorously for 15 minutes, allowed to stand for separation, and the lower organic phase and the middle protein layer were removed. This step was repeated until the white suspension in the middle layer disappeared. The upper aqueous phase was collected, anhydrous ethanol was added to adjust the alcohol content to 62%-65%, and the mixture was allowed to stand overnight at 4°C. The mixture was centrifuged at 4000 rpm for 30 minutes to collect the precipitate. The precipitate was redissolved with 60°C hot water, and the redissolved solution was placed in a 3500Da dialysis bag and dialyzed in distilled water for 48 hours, with the water being replaced every 4 hours. Finally, the dialysate was pre-cooled at -80°C for 2 hours and dried in a vacuum freeze dryer at -50°C and a vacuum degree of 40 Pa for 24 hours to obtain orange peel pectin, which was stored in a drying dish for later use. 3) Enzymatic hydrolysis and enrichment of pectin Enzymatic hydrolysis of pectin: Orange peel pectin was enzymatically hydrolyzed to a pectin concentration of 10.0 mg / mL, and 0.05 mg / mL of pectinase was added. The temperature was 50°C, the treatment was performed for 15 min, and the enzymatic hydrolysis for 15 min was performed. The orange peel pectin O15 was obtained by freeze-drying. (2) Preparation of pectin and monascus pigment complex 1) Prepare a 10.0 mg / mL aqueous solution of orange peel pectin O15, which has been enzymatically hydrolyzed for 15 min, and heat at 60°C with stirring until completely dissolved; 2) Add 1 mol / L H2O2 aqueous solution and Vc, and shake at 40°C for 30 minutes; 3) Add red yeast rice pigment to the reaction flask and stir in the dark at room temperature for 24 h; 4) The resulting solution was dialyzed using a 3500 Da dialysis bag and soaked in distilled water for 48 hours to remove unreacted pigment. The retained solution was lyophilized to obtain a free radical-inducing complex O15-FR of pectin and monascus pigment after enzymatic hydrolysis for 15 minutes, which is a highly stable pectin-monascus pigment complex; The ratio of orange peel pectin O15 aqueous solution: 1 mol / L H2O2 aqueous solution: Vc: red yeast rice pigment is 10:0.2:10.8:12 in mL:mL:mg:mg.

2. The high-stability pectin-monascus pigment complex according to claim 1, characterized in that: The powder in step (1)1) is 60 mesh.

3. Use of the high-stability pectin-monascus pigment complex as claimed in claim 1 or 2 in the preparation of ham sausage.

4. A method for preparing ham sausage using the high-stability pectin-monascus pigment complex according to claim 1 or 2, characterized in that: The steps include: a. After washing the pork, remove the fascia, grind in a meat grinder for 10-15min, add 135 parts by weight of pork, 2-3.5 parts by weight of pectin red yeast rice complex O15-FR, 30-40 parts by weight of sausage solid compound seasoning, stir well and place in a refrigerator at 4 ℃ for 2h, stirring occasionally halfway; b. Wash the casings with clean water and soak them in onion, ginger and cooking wine for 2-3 hours; c. Use a sausage stuffer and cut it into relatively even small sections with a thin thread; d. Steam the ham in cold water for 30 minutes after boiling, then remove from the water. After cooling, the ham is packaged using a vacuum packaging machine.

5. The method according to claim 4, characterized in that: 135 parts by weight of pork, 2.5 parts by weight of pectin-red yeast compound O15-FR, and 33.5 parts by weight of sausage solid compound seasoning.

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