Purple sweet potato anthocyanin system with stable water-oil interface as well as preparation method and application of purple sweet potato anthocyanin system

Abstract

The invention provides a purple sweet potato anthocyanin system with a stable water-oil interface and a preparation method and application thereof, and belongs to the technical field of food processing. The purple sweet potato anthocyanin system is prepared from the following raw materials in parts by mass: 334-390 parts of purple sweet potatoes; 334 to 390 parts of water; 40 to 80 parts of wheat oligopeptide; 8 to 10 parts of amylase; 5 to 8 parts of cellulase; 4 to 8 parts of glucoamylase; 15 to 18 parts of a pH value regulator; 80 to 100 parts of maltitol; 15-25 parts of table salt; 2 to 5 parts of sodium alginate; 50 to 80 parts of medium chain triglyceride; 1-4 parts of phospholipid; 4 to 9 parts of Tween 60; and 8 to 12 parts of sodium caseinate. The purple sweet potato anthocyanin system with the stable water-oil interface is small in particle size and high in heat resistance, can maintain the stability and biological activity of the purple sweet potato anthocyanin in the storage period, meets the requirements of multiple food formulas, tastes pleasant, and is beneficial to expansion of wide application of the purple sweet potato anthocyanin system in the food industry.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and in particular to a purple sweet potato anthocyanin system with stable water-oil interface, and a preparation method and application thereof. Background Art

[0002] Purple sweet potatoes are popular with consumers for their rich nutritional value, including anthocyanins, and their dual medicinal and edible properties. Purple sweet potato anthocyanins, a type of edible, natural, water-soluble pigment extracted from purple sweet potatoes, are highly regarded in the food industry for their diverse physiological benefits, including antioxidant, anti-inflammatory, and chronic disease prevention properties. However, due to their structural characteristics, purple sweet potato anthocyanins are susceptible to environmental influences, resulting in color variability and processing instability. In-depth research into the structural characteristics of purple sweet potato anthocyanins, improving their stability, and expanding their application in food processing are crucial for promoting the development of my country's potato industry.

[0003] While water-oil interface systems for protecting purple sweet potato anthocyanins, such as oil-in-water and water-in-oil-in-water systems, are relatively well-established and already in production, their high oil content makes them difficult to coexist harmoniously with other food ingredients and exhibits poor palatability. To effectively address this dilemma, it is urgent to explore innovative strategies and optimization paths. By fine-tuning the system structure while maintaining or even enhancing the protective efficacy of purple sweet potato anthocyanins, we can develop an anthocyanin protection system that meets the needs of diverse food formulations and has a pleasant taste. This will expand its broad application prospects in the food industry and promote the comprehensive upgrading and innovative development of food quality. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a water-oil interface stable purple sweet potato anthocyanin system and its preparation method and application. The water-oil interface stable purple sweet potato anthocyanin system provided by the present invention has good purple sweet potato anthocyanin protection ability and good palatability.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a purple sweet potato anthocyanin system with stable water-oil interface, which is prepared from the following raw materials in parts by weight:

[0007]

[0008]

[0009] Preferably, the mass ratio of the medium chain triglyceride to sodium caseinate is 5:0.8-1.2;

[0010] The mass ratio of medium-chain triglycerides to phospholipids is 5:0.1-0.4;

[0011] The mass ratio of medium chain triglycerides to Tween 60 is 5:0.4-0.9.

[0012] Preferably, the particle size of the oil particles in the water-oil interface-stabilized purple sweet potato anthocyanin system is 1.20 to 7.09 μm.

[0013] Preferably, the pH regulator includes citric acid and / or sodium citrate; and the pH value of the water-oil interface-stabilized purple sweet potato anthocyanin system is 5.5-6.3.

[0014] Preferably, the final concentration of the purple sweet potato anthocyanin system stabilized by the wheat oligopeptide at the water-oil interface is 4 to 8 wt%;

[0015] The final concentration of the purple potato anthocyanin system stabilized by the amylase at the water-oil interface is 0.8-1.0 wt %;

[0016] The final concentration of the purple sweet potato anthocyanin system stabilized by the cellulase at the water-oil interface is 0.5-0.8 wt %;

[0017] The final concentration of the purple sweet potato anthocyanin system stabilized by the glucoamylase at the water-oil interface is 0.4-0.8 wt %;

[0018] The final concentration of the purple potato anthocyanin system stabilized by the medium-chain triglyceride at the water-oil interface is 5 to 8 wt%;

[0019] The final concentration of the purple sweet potato anthocyanin system stabilized by maltitol at the water-oil interface is 8-10 wt%;

[0020] The final concentration of the purple potato anthocyanin system stabilized by the salt at the water-oil interface is 1.5-2.5 wt %;

[0021] The final concentration of the purple sweet potato anthocyanin system stabilized by sodium alginate at the water-oil interface is 0.2-0.5 wt %.

[0022] The present invention provides a method for preparing the above-mentioned water-oil interface-stabilized purple sweet potato anthocyanin system, comprising the following steps:

[0023] Mixing cooked purple sweet potatoes with water and beating them to obtain purple sweet potato pulp;

[0024] The purple sweet potato pulp is mixed with amylase, cellulase, glucoamylase and a pH regulator, and enzymatically hydrolyzed, inactivated and centrifuged in sequence to obtain a clear liquid to obtain purple sweet potato juice;

[0025] mixing the purple sweet potato juice with wheat oligopeptides, maltitol, sodium alginate and salt to obtain an aqueous phase mixture;

[0026] Mixing medium chain triglycerides with sodium caseinate, phospholipids and Tween 60 to obtain an oil phase mixture;

[0027] The aqueous phase mixture is mixed with the oil phase mixture, and high-pressure homogenization circulation is performed to obtain a purple sweet potato anthocyanin system with a stable water-oil interface.

[0028] Preferably, the cooked purple sweet potato is steamed; the steaming time is 40 to 45 minutes;

[0029] After the purple sweet potato pulp is mixed with amylase, cellulase, glucoamylase and pH regulator, the pH value of the obtained mixed solution is 5.3-5.8.

[0030] Preferably, the enzymatic hydrolysis temperature is 40-45°C and the time is 2.5-3h;

[0031] The temperature of the enzyme inactivation treatment is 80-90° C., and the time is 5-10 minutes.

[0032] Preferably, the centrifugal speed is 5000-6000 rpm, and the time is 15-20 min;

[0033] The pressure of the high-pressure homogenization cycle is 28-34 MPa, and the number of cycles is 3-5 times.

[0034] The present invention provides application of the purple sweet potato anthocyanin system with stable water-oil interface in the field of food.

[0035] The present invention provides a purple sweet potato anthocyanin system with a stable water-oil interface, which is prepared from the following raw materials in parts by weight: 334-390 parts by weight of purple sweet potato; 334-390 parts by weight of water; 40-80 parts by weight of wheat oligopeptides; 8-10 parts by weight of amylase; 5-8 parts by weight of cellulase; 4-8 parts by weight of glucoamylase; 15-18 parts by weight of pH regulator; 80-100 parts by weight of maltitol; 15-25 parts by weight of salt; 2-5 parts by weight of sodium alginate; 50-80 parts by weight of medium-chain triglycerides; 1-4 parts by weight of phospholipids; 4-9 parts by weight of Tween 60; and 8-12 parts by weight of sodium caseinate. In the present invention, the wheat oligopeptides play the role of increasing nutritional content, protecting color and regulating the oil-water interface, the amylase, cellulase and glucoamylase play the role of enzymatically decomposing starch and cellulose, the maltitol and salt play the role of seasoning and regulating the oil-water interface, and the sodium alginate plays the role of binding ions and protecting color. Medium-chain triglycerides play a role in maintaining the stability of purple sweet potato anthocyanins and forming an emulsion system as an oil phase, while sodium caseinate, phospholipids and Tween 60 play an emulsifying role. In the present invention, medium-chain triglycerides serve as a dispersed phase with small molecules and stable properties. Sodium caseinate, phospholipids and Tween 60 serve as emulsifiers to reduce the surface tension between the water-oil interface and provide electrostatic repulsion, so that the medium-chain triglycerides are evenly distributed in the continuous aqueous phase. At the same time, wheat oligopeptides are adsorbed at the oil-water interface through their amphiphilic structure, maltitol delays the aggregation of oil droplets by increasing the viscosity of the aqueous phase, and salt affects the protein adsorption behavior by changing the electrostatic interaction, thereby regulating the entire water-oil system and making it have good stability. The water-oil interface-stabilized purple sweet potato anthocyanin dispersion system prepared by the present invention has high stability, small particle size, and strong heat resistance, and can maintain the stability and biological activity of purple sweet potato anthocyanins during storage. The water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention maintains or even improves the protective efficacy of purple sweet potato anthocyanins, meets the needs of diversified food formulations, and has a pleasant taste. It is conducive to expanding its wide application in the food industry and promoting the comprehensive upgrading and innovative development of the quality of purple sweet potato anthocyanin foods.

[0036] The present invention provides a method for preparing the above-mentioned water-oil interface stable purple sweet potato anthocyanin system. The preparation method of the water-oil interface stable purple sweet potato anthocyanin system is simple, has low production cost, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The particle size distribution of the purple sweet potato anthocyanin system stabilized at the water-oil interface obtained in Example 1;

[0038] Figure 2 This is a microstructure diagram of the purple sweet potato anthocyanin system stabilized at the water-oil interface obtained in Example 1;

[0039] Figure 3The interfacial tension of the purple sweet potato anthocyanin system stabilized at the water-oil interface obtained in Example 1;

[0040] Figure 4 The particle size distribution of the purple sweet potato anthocyanin system stabilized at the water-oil interface obtained in Example 2;

[0041] Figure 5 The particle size distribution of the purple sweet potato anthocyanin system stabilized at the water-oil interface obtained in Example 3;

[0042] Figure 6 The thermal stability test results of the systems obtained in Examples 1 to 3 and Comparative Examples 1 to 6 are as follows;

[0043] Figure 7 This is a graph showing the degradation of anthocyanin in the thermal stability test of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0044] The present invention provides a purple sweet potato anthocyanin system with stable water-oil interface, which is prepared from the following raw materials in parts by weight:

[0045]

[0046] Unless otherwise specified, the raw materials used in the present invention are all commercially available.

[0047] In terms of mass fraction, the raw materials of the water-oil interface stable purple sweet potato anthocyanin system provided by the present invention include 334 to 390 parts by mass of purple sweet potato, preferably 350 to 380 parts by mass, specifically 334, 352, 367, 376, 385 or 390 parts by mass.

[0048] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention include 334 to 390 parts by mass of water, preferably 350 to 380 parts by mass, specifically 334, 352, 367, 376, 385 or 390 parts by mass. In the present invention, the water is preferably drinking water.

[0049] Based on the mass fraction of the purple sweet potato, the raw materials of the purple sweet potato anthocyanin system with stable water-oil interface provided by the present invention include 40 to 80 parts by mass of wheat oligopeptides, preferably 55 to 65 parts by mass, and specifically 40, 50, 55, 65, 70 or 80 parts by mass. In the present invention, the role of the wheat oligopeptides is to increase nutritional content, protect color and regulate the water-oil interface.

[0050] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention include 8 to 10 mass parts of amylase, specifically 8, 9 or 10 mass parts. In the present invention, the role of the amylase is to enzymatically hydrolyze the starch in the purple sweet potato, reduce the viscosity of the purple sweet potato slurry, and enhance fluidity.

[0051] Based on the mass fraction of the purple sweet potato, the raw material of the water-oil interface stable purple sweet potato anthocyanin system provided by the present invention is 5 to 10 parts by mass of cellulase, specifically 5, 6, 7, 8, 9 or 10 parts. In the present invention, the role of the cellulase is to enzymatically hydrolyze the cellulose in the purple sweet potato, reduce the viscosity of the purple sweet potato pulp, and enhance the fluidity.

[0052] Based on the mass fraction of the purple sweet potato, the raw material of the water-oil interface stable purple sweet potato anthocyanin system provided by the present invention is 4 to 8 parts by mass of glucoamylase, specifically 4, 5, 6, 7 or 8 parts. In the present invention, the role of the glucoamylase is to enzymatically hydrolyze the starch in the purple sweet potato, reduce the viscosity of the purple sweet potato slurry, and enhance fluidity.

[0053] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention include 15 to 18 parts by mass of a pH adjuster, preferably 16 to 17 parts. In the present invention, the pH adjuster includes citric acid and / or sodium citrate, specifically a citric acid-sodium citrate buffer.

[0054] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention include 80 to 100 parts by mass of maltitol, preferably 85 to 95 parts by mass. In the present invention, the maltitol serves as a flavoring and delays the aggregation of oil droplets by increasing the viscosity of the water phase.

[0055] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention include 15 to 25 parts by mass of salt, preferably 18 to 22 parts by mass. In the present invention, the salt serves as a seasoning and affects protein adsorption behavior by changing electrostatic interactions, thereby regulating the entire water-oil system and providing good stability.

[0056] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention include 2 to 5 parts by mass of sodium alginate, preferably 3 to 4 parts by mass. In the present invention, the role of the sodium alginate is synergistic emulsification, and through the adsorption of long-chain molecules at the water-oil interface to form a protective layer, the entire water-oil system is regulated to have good stability.

[0057] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface stable purple sweet potato anthocyanin system provided by the present invention include 50 to 80 parts by mass of medium-chain triglycerides, preferably 60 to 70 parts by mass. In the present invention, the role of the medium-chain triglycerides is to form an emulsion system as an oil phase and maintain the stability of the purple sweet potato anthocyanins.

[0058] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention include 1 to 4 mass parts of phospholipids, preferably 2 to 3 mass parts. In the present invention, the role of the phospholipids is to act as an emulsifier to stabilize the water-oil interface.

[0059] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention include 4 to 9 mass parts of Tween 60, preferably 5 to 8 mass parts. In the present invention, the role of the Tween 60 is to stabilize the water-oil interface as an emulsifier.

[0060] Based on the mass fraction of the purple sweet potato, the raw materials of the water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention include 8 to 12 mass parts of sodium caseinate, specifically 8, 9, 10, 11 or 12 mass parts. In the present invention, the role of the sodium caseinate is to act as an emulsifier to stabilize the water-oil interface.

[0061] In the present invention, the mass ratio of the medium chain triglyceride to sodium caseinate is preferably 5:0.8-1.2. As a specific embodiment of the present invention, the mass ratio of the medium chain triglyceride to sodium caseinate can be 5:0.8, 5:1 or 5:1.2.

[0062] In the present invention, the final concentration of the purple sweet potato anthocyanin system stabilized by the wheat oligopeptide at the water-oil interface is preferably 4-8wt%, specifically 4wt%, 5wt%, 6wt%, 7wt% or 8wt%. In the present invention, the final concentration of the purple sweet potato anthocyanin system stabilized by the amylase at the water-oil interface is preferably 0.8-1.0wt%, specifically 0.8wt%, 0.85wt%, 0.9wt%, 0.95wt% or 1wt%. In the present invention, the final concentration of the purple sweet potato anthocyanin system stabilized by the cellulase at the water-oil interface is preferably 0.5-0.8wt%, specifically 0.5wt%, 0.6wt%, 0.7wt% or 0.8wt%. In the present invention, the final concentration of the purple sweet potato anthocyanin system stabilized by the glucoamylase at the water-oil interface is preferably 0.4-0.8wt%, specifically 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt% or 0.8wt%. In the present invention, the final concentration of the maltitol in the purple sweet potato anthocyanin system stabilized at the water-oil interface is preferably 8-10wt%, specifically 8wt%, 8.5wt%, 9wt%, 9.5wt% or 10wt%. In the present invention, the final concentration of the salt in the purple sweet potato anthocyanin system stabilized at the water-oil interface is preferably 1.5-2.5wt%, specifically 1.5wt%, 2wt% or 2.5wt%. In the present invention, the final concentration of the sodium alginate in the purple sweet potato anthocyanin system stabilized at the water-oil interface is preferably 0.2-0.5wt%, specifically 0.2wt%, 0.3wt%, 0.4wt% or 0.5wt%. In the present invention, the final concentration of the medium-chain triglyceride in the purple sweet potato anthocyanin system stabilized at the water-oil interface is preferably 5-8wt%, specifically 5wt%, 6wt%, 7wt% or 8wt%. In the present invention, the final concentration of the purple sweet potato anthocyanin system stabilized by the phospholipid at the water-oil interface is preferably 0.1-0.4wt%, specifically 0.1wt%, 0.2wt%, 0.3wt% or 0.4wt%. In the present invention, the final concentration of the purple sweet potato anthocyanin system stabilized by the Tween 60 at the water-oil interface is preferably 0.4-0.9wt%, specifically 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt% or 0.9wt%.

[0063] In the present invention, the particle size of the oil (dispersed phase) particles in the water-oil interface-stabilized purple sweet potato anthocyanin system is preferably 1.20 to 7.09 μm, and more preferably 2.59 to 2.64 μm.

[0064] In the present invention, the pH value of the water-oil interface-stabilized purple sweet potato anthocyanin system is 5.5 to 6.3, and more preferably 5.7 to 6.1.

[0065] The present invention provides a method for preparing the above-mentioned water-oil interface-stabilized purple sweet potato anthocyanin system, comprising the following steps:

[0066] Mixing cooked purple sweet potatoes with water and beating them to obtain purple sweet potato pulp;

[0067] The purple sweet potato pulp is mixed with amylase, cellulase, glucoamylase and a pH regulator, and enzymatically hydrolyzed, inactivated and centrifuged in sequence to obtain a clear liquid to obtain purple sweet potato juice;

[0068] mixing the purple sweet potato juice with wheat oligopeptides, maltitol, sodium alginate and salt to obtain an aqueous phase mixture;

[0069] Mixing medium chain triglycerides with sodium caseinate, phospholipids and Tween 60 to obtain an oil phase mixture;

[0070] The aqueous phase mixture is mixed with the oil phase mixture, and high-pressure homogenization circulation is performed to obtain a purple sweet potato anthocyanin system with a stable water-oil interface.

[0071] The present invention mixes cooked purple sweet potatoes with water and pulps them to obtain purple sweet potato pulp. In the present invention, the purple sweet potatoes are preferably washed and / or peeled purple sweet potatoes. The present invention has no particular requirements for the variety of the purple sweet potatoes, and any variety of purple sweet potatoes is applicable to the preparation method of the present invention.

[0072] In the present invention, the cooked purple sweet potato is preferably steamed; the steaming temperature is preferably 95-100°C, the time is preferably 40-45 minutes, more preferably 42-44 minutes. The present invention preferably uses a wall-breaking machine for the beating, the power of the beating is preferably 800-1000W, and the time is preferably 8-10 minutes.

[0073] After obtaining the purple sweet potato pulp, the present invention mixes the purple sweet potato pulp with amylase, cellulase, glucoamylase, and a pH adjuster, and sequentially performs enzymatic hydrolysis, enzyme inactivation, and centrifugation to obtain purple sweet potato juice. In the present invention, after the purple sweet potato pulp is mixed with the amylase, cellulase, glucoamylase, and pH adjuster, the pH value of the resulting mixture is preferably 5.3 to 5.8, more preferably 5.5 to 5.6.

[0074] In the present invention, the enzymatic hydrolysis is preferably an oscillation enzymatic hydrolysis, and the oscillation rate is preferably 100 to 120 times per minute. In the present invention, the temperature of the enzymatic hydrolysis is preferably 40 to 45°C, more preferably 42 to 44°C, and the time is preferably 2.5 to 3 hours. In the present invention, the temperature of the enzyme inactivation treatment is preferably 80 to 90°C, more preferably 85°C, and the time is preferably 5 to 10 minutes, more preferably 6 to 8 minutes.

[0075] In the present invention, the centrifugal speed is preferably 5000-6000 rpm, and the time is preferably 15-20 min, more preferably 16-18 min. After the centrifugation, the present invention takes the clarified portion of the obtained centrifuge liquid to obtain purple sweet potato juice.

[0076] After obtaining the purple sweet potato juice, the present invention mixes the purple sweet potato juice with wheat oligopeptides, maltitol, sodium alginate and salt to obtain an aqueous phase mixture. The present invention has no special requirements for the mixing method, and any mixing method well known in the art can be used, such as stirring and mixing.

[0077] The present invention mixes medium-chain triglycerides with sodium caseinate, phospholipids, and Tween 60 to obtain an oil phase mixture. The present invention has no special requirements for the mixing method, and a mixing method well known to those skilled in the art can be used, specifically, stirring and mixing.

[0078] After obtaining the aqueous phase mixture and the oil phase mixture, the present invention mixes the aqueous phase mixture with the oil phase mixture and performs a high-pressure homogenization cycle to obtain a purple sweet potato anthocyanin system with a stable water-oil interface. In the present invention, the pressure of the high-pressure homogenization cycle is preferably 28 to 34 MPa, more preferably 32 to 34 MPa; the number of cycles is preferably 3 to 5 times, more preferably 4 times.

[0079] After the high-pressure homogenization cycle, the present invention preferably sterilizes the obtained water-oil interface-stabilized purple sweet potato anthocyanin system. In the present invention, the sterilization temperature is preferably 90-95° C., and the time is preferably 15-25 minutes, more preferably 20 minutes.

[0080] The present invention provides the application of the above-mentioned water-oil interface-stabilized purple sweet potato anthocyanin system in the field of food. In the present invention, the food is preferably a dairy product or a beverage product.

[0081] The water-oil interface-stabilized purple sweet potato anthocyanin system provided by the present invention, its preparation method and application are described in detail below with reference to the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0082] Example 1

[0083] A method for preparing a purple sweet potato anthocyanin system that is stable at a water-oil interface comprises the following steps:

[0084] (1) Wash and peel fresh purple sweet potatoes, cut into pieces, and steam them in a steamer for 45 minutes. Then, beat them with water in a 1:1 mass ratio to obtain 780 g of purple sweet potato pulp;

[0085] (2) adding 9 g of amylase, 5 g of cellulase, and 6 g of glucoamylase to the purple sweet potato pulp in step (1);

[0086] (3) adding 15 g of a pH regulator to the purple sweet potato pulp in step (2) to adjust the pH value; wherein the pH regulator is a mixture of 0.1 mol / L citric acid solution and 0.1 mol / L sodium citrate solution, and the volume ratio of the citric acid solution to the sodium citrate solution is 1:10;

[0087] (4) starting enzymatic hydrolysis of the purple sweet potato pulp in step (3);

[0088] (5) inactivating the enzyme in the purple sweet potato pulp from step (4);

[0089] (6) centrifuging the purple sweet potato pulp from step (5) to obtain clarified purple sweet potato juice;

[0090] (7) adding 60 g of wheat oligopeptides, 90 g of maltitol, 4 g of sodium alginate and 20 g of salt to the purple sweet potato juice in step (6) to obtain purple sweet potato juice containing peptides, sugars and salts;

[0091] (8) Add 8 g of sodium caseinate, 2 g of phospholipids, and 7 g of Tween 60 to 50 g of medium-chain triglycerides and mix well to obtain an oil phase mixture;

[0092] (9) The mixed solution in step (7) is added to the mixture in step (8), and a purple sweet potato anthocyanin system with a stable water-oil interface is obtained after high-pressure homogenization circulation.

[0093] (10) sterilizing the purple sweet potato anthocyanin system stabilized at the water-oil interface in step (9).

[0094] In this embodiment, the beater power in step (1) is 800W, and the beating time is 10 minutes.

[0095] In this embodiment, the pH value in step (3) is 5.5.

[0096] In this embodiment, the enzymatic hydrolysis temperature in step (4) is 45° C. and the enzymatic hydrolysis time is 3 hours.

[0097] In this embodiment, the enzyme inactivation temperature in step (5) is 85° C. and the enzyme inactivation time is 8 minutes.

[0098] In this embodiment, the centrifugal speed in step (6) is 5000 rpm and the centrifugal time is 20 minutes.

[0099] In this embodiment, the final concentration of the medium-chain triglyceride in the system in step (8) is 5 wt %, and the mass ratio of the medium-chain triglyceride to sodium caseinate is 5:0.8.

[0100] In this embodiment, the high-pressure homogenization cycle parameter in step (9) is 30 MPa, and the number of cycles is 5 times.

[0101] In this embodiment, the sterilization temperature in step (10) is 95° C. and the sterilization time is 20 minutes.

[0102] The particle size distribution of the purple potato anthocyanin system with stable water-oil interface is as follows: Figure 1 As shown, it can be seen that the particle size of the prepared water-oil interface stable purple sweet potato anthocyanin system is measured to be about 2.59 μm.

[0103] The microstructure of the purple potato anthocyanin system stabilized at the water-oil interface is shown in the figure below. Figure 2 As shown by Figure 2 It can be seen that the particle size of the system is very small, there is no aggregation phenomenon, and the distribution is uniform, indicating that the water-oil system has good stability.

[0104] The water-oil interfacial tension of the purple potato anthocyanin system with stable water-oil interface is as follows: Figure 3 As shown. The interface instrument of the detection system OSA100 was used to detect the dynamic interfacial tension of the water-oil interface of the purple sweet potato anthocyanin system with stable water-oil interface. Figure 3 It can be seen that the interfacial tension of the water-oil interface is constantly decreasing and stabilized at 8.23mN / m, indicating that the emulsifier is effectively adsorbed on the water-oil interface, making the oil droplets more dispersed, which increases the survival sites of anthocyanins at the water-oil interface and can better maintain the stability of anthocyanins.

[0105] Example 2

[0106] A method for preparing a purple sweet potato anthocyanin system that is stable at a water-oil interface comprises the following steps:

[0107] (1) Wash and peel fresh purple sweet potatoes, cut into pieces, and steam in a steamer for 40 min. Then, blend with water in a 1:1 mass ratio to obtain 780 g of purple sweet potato pulp;

[0108] (2) adding 8 g of amylase, 5 g of cellulase, and 6 g of glucoamylase to the purple sweet potato pulp in step (1);

[0109] (3) adding 15 g of a pH regulator to the purple sweet potato pulp in step (2) to adjust the pH value; wherein the pH regulator is a mixture of 0.1 mol / L citric acid solution and 0.1 mol / L sodium citrate solution, and the volume ratio of the citric acid solution to the sodium citrate solution is 1:10;

[0110] (4) starting enzymatic hydrolysis of the purple sweet potato pulp in step (3);

[0111] (5) inactivating the enzyme in the purple sweet potato pulp from step (4);

[0112] (6) centrifuging the purple sweet potato pulp from step (5) to obtain clarified purple sweet potato juice;

[0113] (7) adding 70 g of wheat oligopeptides, 90 g of maltitol, 4 g of sodium alginate and 25 g of salt to the purple sweet potato juice in step (6) to obtain purple sweet potato juice containing peptides, sugars and salts;

[0114] (8) Add 12 g sodium caseinate, 2 g phospholipids, and 7 g Tween 60 to 50 g medium chain triglycerides and mix well to obtain an oil phase mixture;

[0115] (9) The mixed solution in step (7) is added to the mixture in step (8), and a purple sweet potato anthocyanin system with a stable water-oil interface is obtained after high-pressure homogenization circulation.

[0116] (10) sterilizing the purple sweet potato anthocyanin system stabilized at the water-oil interface in step (9).

[0117] In this embodiment, the power of the beater in step (1) is 800W and the beating time is 10 minutes.

[0118] In this embodiment, the pH value in step (3) is 5.5.

[0119] In this embodiment, the enzymatic hydrolysis temperature in step (4) is 48° C. and the enzymatic hydrolysis time is 3 hours.

[0120] In this embodiment, the enzyme inactivation temperature in step (5) is 90° C. and the enzyme inactivation time is 5 minutes.

[0121] In this embodiment, the centrifugal speed in step (6) is 5000 rpm and the centrifugal time is 18 minutes.

[0122] In this embodiment, the final concentration of the medium-chain triglyceride in the system in step (8) is 5 wt %, and the mass ratio of the medium-chain triglyceride to sodium caseinate is 5:1.2.

[0123] In this embodiment, the high-pressure homogenization cycle parameter in step (9) is 32 MPa, and the number of cycles is 4 times.

[0124] In this embodiment, the sterilization temperature in step (10) is 95°C and the sterilization time is 20 minutes. The interfacial tension of the water-oil interface of the purple sweet potato anthocyanin system with stable water-oil interface is stable at 9.06 mN / m, and the particle size distribution is as follows: Figure 4 As shown, it can be seen that the particle size of the prepared water-oil interface stable purple sweet potato anthocyanin system is measured to be about 2.64 μm.

[0125] Example 3

[0126] A method for preparing a purple sweet potato anthocyanin system that is stable at a water-oil interface comprises the following steps:

[0127] (1) Wash and peel fresh purple sweet potatoes, cut into pieces, and steam them in a steamer for 42 minutes. Then, blend them with water in a 1:1 mass ratio to obtain 780 g of purple sweet potato pulp;

[0128] (2) adding 9 g of amylase, 5 g of cellulase, and 6 g of glucoamylase to the purple sweet potato pulp in step (1);

[0129] (3) adding 15 g of a pH regulator to the purple sweet potato pulp in step (2) to adjust the pH value; wherein the pH regulator is a mixture of 0.1 mol / L citric acid solution and 0.1 mol / L sodium citrate solution, and the volume ratio of the citric acid solution to the sodium citrate solution is 1:10;

[0130] (4) starting enzymatic hydrolysis of the purple sweet potato pulp in step (3);

[0131] (5) inactivating the enzyme in the purple sweet potato pulp from step (4);

[0132] (6) centrifuging the purple sweet potato pulp from step (5) to obtain clarified purple sweet potato juice;

[0133] (7) adding 60 g of wheat oligopeptides, 90 g of maltitol, 4 g of sodium alginate and 20 g of salt to the purple sweet potato juice in step (6) to obtain purple sweet potato juice containing peptides, sugars and salts;

[0134] (8) Add 10 g sodium caseinate, 2 g phospholipids, and 7 g Tween 60 to 50 g medium chain triglycerides and mix well to obtain an oil phase mixture;

[0135] (9) The mixed solution in step (7) is added to the mixture in step (8), and a purple sweet potato anthocyanin system with a stable water-oil interface is obtained after high-pressure homogenization circulation.

[0136] (10) sterilizing the purple sweet potato anthocyanin system stabilized at the water-oil interface in step (9).

[0137] In this embodiment, the beater power in step (1) is 800W, and the beating time is 10 minutes.

[0138] In this embodiment, the pH value in step (3) is 5.5.

[0139] In this embodiment, the enzymatic hydrolysis temperature in step (4) is 45° C. and the enzymatic hydrolysis time is 3 hours.

[0140] In this embodiment, the enzyme inactivation temperature in step (5) is 88° C. and the enzyme inactivation time is 6 minutes.

[0141] In this embodiment, the centrifugal speed in step (6) is 5000 rpm and the centrifugal time is 20 minutes.

[0142] In this embodiment, the final concentration of the medium-chain triglyceride in the system in step (8) is 5 wt %, and the mass ratio of the medium-chain triglyceride to sodium caseinate is 5:1.0.

[0143] In this embodiment, the high-pressure homogenization cycle parameter in step (9) is 28 MPa, and the number of cycles is 5 times.

[0144] In this embodiment, the sterilization temperature in step (10) is 95°C and the sterilization time is 20 minutes. The interfacial tension of the water-oil interface in the obtained purple sweet potato anthocyanin system with stable water-oil interface is stable at 8.03 mN / m, and the particle size distribution is as follows: Figure 5 As shown, it can be seen that the particle size of the prepared water-oil interface stable purple sweet potato anthocyanin system is measured to be about 2.62 μm.

[0145] Comparative Example 1

[0146] (1) Wash and peel fresh purple sweet potatoes, cut into pieces, and steam them in a steamer for 45 minutes. Then, beat them with water in a 1:1 mass ratio to obtain 780 g of purple sweet potato pulp;

[0147] (2) adding 9 g of amylase, 5 g of cellulase, and 6 g of glucoamylase to the purple sweet potato pulp in step (1);

[0148] (3) adding 15 g of a pH regulator to the purple sweet potato pulp in step (2) to adjust the pH value; wherein the pH regulator is a mixture of 0.1 mol / L citric acid solution and 0.1 mol / L sodium citrate solution, and the volume ratio of the citric acid solution to the sodium citrate solution is 1:10;

[0149] (4) starting enzymatic hydrolysis of the purple sweet potato pulp in step (3);

[0150] (5) inactivating the enzyme in the purple sweet potato pulp from step (4);

[0151] (6) centrifuging the purple sweet potato pulp from step (5) to obtain clarified purple sweet potato juice;

[0152] (7) adding 60 g of wheat oligopeptides, 90 g of maltitol, 4 g of sodium alginate and 20 g of salt to the purple sweet potato juice in step (6) to obtain purple sweet potato juice containing peptides, sugars and salts;

[0153] (8) The solution in step (7) is subjected to high-pressure homogenization and circulation to obtain a purple sweet potato anthocyanin system.

[0154] (9) sterilizing the purple sweet potato anthocyanin system stabilized at the water-oil interface in step (8).

[0155] In this embodiment, the beater power in step (1) is 800W, and the beating time is 10 minutes.

[0156] In this embodiment, the pH value in step (3) is 5.5.

[0157] In this embodiment, the enzymatic hydrolysis temperature in step (4) is 45° C. and the enzymatic hydrolysis time is 3 hours.

[0158] In this embodiment, the enzyme inactivation temperature in step (5) is 85° C. and the enzyme inactivation time is 8 minutes.

[0159] In this embodiment, the centrifugal speed in step (6) is 5000 rpm and the centrifugal time is 20 minutes.

[0160] In this embodiment, the high-pressure homogenization cycle parameter in step (8) is 30 MPa, and the number of cycles is 5 times.

[0161] In this embodiment, the sterilization temperature in step (9) is 95° C. and the sterilization time is 20 minutes.

[0162] Comparative Example 2

[0163] A method for preparing a purple sweet potato anthocyanin system that is stable at a water-oil interface comprises the following steps:

[0164] (1) Wash and peel fresh purple sweet potatoes, cut into pieces, and steam in a steamer for 45 minutes. Then, blend with water in a 1:1 mass ratio to obtain 780 g of purple sweet potato pulp;

[0165] (2) adding 9 g of amylase, 5 g of cellulase, and 6 g of glucoamylase to the purple sweet potato pulp in step (1);

[0166] (3) adding 15 g of a pH regulator to the purple sweet potato pulp in step (2) to adjust the pH value; wherein the pH regulator is a mixture of 0.1 mol / L citric acid solution and 0.1 mol / L sodium citrate solution, and the volume ratio of the citric acid solution to the sodium citrate solution is 1:10;

[0167] (4) starting enzymatic hydrolysis of the purple sweet potato pulp in step (3);

[0168] (5) inactivating the enzyme in the purple sweet potato pulp from step (4);

[0169] (6) centrifuging the purple sweet potato pulp from step (5) to obtain clarified purple sweet potato juice;

[0170] (7) adding 60 g of wheat oligopeptides, 90 g of maltitol, 4 g of sodium alginate and 20 g of salt to the purple sweet potato juice in step (6) to obtain purple sweet potato juice containing peptides, sugars and salts;

[0171] (8) Add 8 g of sodium caseinate, 2 g of phospholipids, and 7 g of Tween 60 to 50 g of soybean oil and mix well to obtain an oil phase mixture;

[0172] (9) The mixed solution in step (7) is added to the mixture in step (8), and a purple sweet potato anthocyanin system with a stable water-oil interface is obtained after high-pressure homogenization circulation.

[0173] (10) sterilizing the purple sweet potato anthocyanin system stabilized at the water-oil interface in step (9).

[0174] In this embodiment, the beater power in step (1) is 800W, and the beating time is 10 minutes.

[0175] In this embodiment, the pH value in step (3) is 5.5.

[0176] In this embodiment, the enzymatic hydrolysis temperature in step (4) is 45° C. and the enzymatic hydrolysis time is 3 hours.

[0177] In this embodiment, the enzyme inactivation temperature in step (5) is 85° C. and the enzyme inactivation time is 8 minutes.

[0178] In this embodiment, the centrifugal speed in step (6) is 5000 rpm and the centrifugal time is 20 minutes.

[0179] In this embodiment, the final concentration of the soybean oil in the system in step (8) is 5 wt %, and the mass ratio of the soybean oil to sodium caseinate is 5:0.8.

[0180] In this embodiment, the high-pressure homogenization cycle parameter in step (9) is 30 MPa, and the number of cycles is 5 times.

[0181] In this embodiment, the sterilization temperature in step (10) is 95° C. and the sterilization time is 20 minutes.

[0182] Comparative Example 3

[0183] A method for preparing a purple sweet potato anthocyanin system that is stable at a water-oil interface comprises the following steps:

[0184] (1) Wash and peel fresh purple sweet potatoes, cut into pieces, and steam in a steamer for 45 minutes. Then, blend with water in a 1:1 mass ratio to obtain 780 g of purple sweet potato pulp;

[0185] (2) adding 9 g of amylase, 5 g of cellulase, and 6 g of glucoamylase to the purple sweet potato pulp in step (1);

[0186] (3) adding 15 g of a pH regulator to the purple sweet potato pulp in step (2) to adjust the pH value; wherein the pH regulator is a mixture of 0.1 mol / L citric acid solution and 0.1 mol / L sodium citrate solution, and the volume ratio of the citric acid solution to the sodium citrate solution is 1:10;

[0187] (4) starting enzymatic hydrolysis of the purple sweet potato pulp in step (3);

[0188] (5) inactivating the enzyme in the purple sweet potato pulp from step (4);

[0189] (6) centrifuging the purple sweet potato pulp from step (5) to obtain clarified purple sweet potato juice;

[0190] (7) adding 60 g of wheat oligopeptides, 90 g of maltitol, 4 g of sodium alginate and 20 g of salt to the purple sweet potato juice in step (6) to obtain purple sweet potato juice containing peptides, sugars and salts;

[0191] (8) Add 8 g of sodium caseinate, 2 g of phospholipids, and 7 g of Tween 60 to 50 g of corn oil and mix well to obtain an oil phase mixture;

[0192] (9) The mixed solution in step (7) is added to the mixture in step (8), and a purple sweet potato anthocyanin system with a stable water-oil interface is obtained after high-pressure homogenization circulation.

[0193] (10) sterilizing the purple sweet potato anthocyanin system stabilized at the water-oil interface in step (9).

[0194] In this embodiment, the beater power in step (1) is 800W, and the beating time is 10 minutes.

[0195] In this embodiment, the pH value in step (3) is 5.5.

[0196] In this embodiment, the enzymatic hydrolysis temperature in step (4) is 45° C. and the enzymatic hydrolysis time is 3 hours.

[0197] In this embodiment, the enzyme inactivation temperature in step (5) is 85° C. and the enzyme inactivation time is 8 minutes.

[0198] In this embodiment, the centrifugal speed in step (6) is 5000 rpm and the centrifugal time is 20 minutes.

[0199] In this embodiment, the final concentration of the corn oil in the system in step (8) is 5 wt %, and the mass ratio of the corn oil to sodium caseinate is 5:0.8.

[0200] In this embodiment, the high-pressure homogenization cycle parameter in step (9) is 30 MPa, and the number of cycles is 5 times.

[0201] In this embodiment, the sterilization temperature in step (10) is 95° C. and the sterilization time is 20 minutes.

[0202] Comparative Example 4

[0203] A method for preparing a purple sweet potato anthocyanin system that is stable at a water-oil interface comprises the following steps:

[0204] (1) Wash and peel fresh purple sweet potatoes, cut into pieces, and steam in a steamer for 45 minutes. Then, blend with water in a 1:1 mass ratio to obtain 780 g of purple sweet potato pulp;

[0205] (2) adding 9 g of amylase, 5 g of cellulase, and 6 g of glucoamylase to the purple sweet potato pulp in step (1);

[0206] (3) adding 15 g of a pH regulator to the purple sweet potato pulp in step (2) to adjust the pH value; wherein the pH regulator is a mixture of 0.1 mol / L citric acid solution and 0.1 mol / L sodium citrate solution, and the volume ratio of the citric acid solution to the sodium citrate solution is 1:10;

[0207] (4) starting enzymatic hydrolysis of the purple sweet potato pulp in step (3);

[0208] (5) inactivating the enzyme in the purple sweet potato pulp from step (4);

[0209] (6) centrifuging the purple sweet potato pulp from step (5) to obtain clarified purple sweet potato juice;

[0210] (7) Add 8 g of sodium caseinate, 2 g of phospholipids, and 7 g of Tween 60 to 50 g of medium-chain triglycerides and mix well to obtain an oil phase mixture;

[0211] (8) The clarified purple sweet potato juice in step (6) is added to the mixture in step (7), and a purple sweet potato anthocyanin system with a stable water-oil interface is obtained after high-pressure homogenization circulation.

[0212] (9) sterilizing the purple sweet potato anthocyanin system stabilized at the water-oil interface in step (8).

[0213] In this embodiment, the beater power in step (1) is 800W, and the beating time is 10 minutes.

[0214] In this embodiment, the pH value in step (3) is 5.5.

[0215] In this embodiment, the enzymatic hydrolysis temperature in step (4) is 45° C. and the enzymatic hydrolysis time is 3 hours.

[0216] In this embodiment, the enzyme inactivation temperature in step (5) is 85° C. and the enzyme inactivation time is 8 minutes.

[0217] In this embodiment, the centrifugal speed in step (6) is 5000 rpm and the centrifugal time is 20 minutes.

[0218] In this embodiment, the final concentration of the medium-chain triglyceride in the system in step (8) is 5 wt %, and the mass ratio of the medium-chain triglyceride to sodium caseinate is 5:0.8.

[0219] In this embodiment, the high-pressure homogenization cycle parameter in step (9) is 30 MPa, and the number of cycles is 5 times.

[0220] In this embodiment, the sterilization temperature in step (10) is 95° C. and the sterilization time is 20 minutes.

[0221] Comparative Example 5

[0222] A method for preparing a purple sweet potato anthocyanin system that is stable at a water-oil interface comprises the following steps:

[0223] (1) Wash and peel fresh purple sweet potatoes, cut into pieces, and steam in a steamer for 45 minutes. Then, blend with water in a 1:1 mass ratio to obtain 780 g of purple sweet potato pulp;

[0224] (2) adding 9 g of amylase, 5 g of cellulase, and 6 g of glucoamylase to the purple sweet potato pulp in step (1);

[0225] (3) adding 15 g of a pH regulator to the purple sweet potato pulp in step (2) to adjust the pH value; wherein the pH regulator is a mixture of 0.1 mol / L citric acid solution and 0.1 mol / L sodium citrate solution, and the volume ratio of the citric acid solution to the sodium citrate solution is 1:10;

[0226] (4) starting enzymatic hydrolysis of the purple sweet potato pulp in step (3);

[0227] (5) inactivating the enzyme in the purple sweet potato pulp from step (4);

[0228] (6) centrifuging the purple sweet potato pulp from step (5) to obtain clarified purple sweet potato juice;

[0229] (7) adding 60 g of wheat oligopeptides, 90 g of maltitol, 4 g of sodium alginate and 20 g of salt to the purple sweet potato juice in step (6) to obtain purple sweet potato juice containing peptides, sugars and salts;

[0230] (8) Add 16 g sodium caseinate, 2 g phospholipids, and 7 g Tween 60 to 50 g medium chain triglycerides and mix well to obtain an oil phase mixture;

[0231] (9) The mixed solution in step (7) is added to the mixture in step (8), and a purple sweet potato anthocyanin system with a stable water-oil interface is obtained after high-pressure homogenization circulation.

[0232] (10) sterilizing the purple sweet potato anthocyanin system stabilized at the water-oil interface in step (9).

[0233] In this embodiment, the beater power in step (1) is 800W, and the beating time is 10 minutes.

[0234] In this embodiment, the pH value in step (3) is 5.5.

[0235] In this embodiment, the enzymatic hydrolysis temperature in step (4) is 45° C. and the enzymatic hydrolysis time is 3 hours.

[0236] In this embodiment, the enzyme inactivation temperature in step (5) is 85° C. and the enzyme inactivation time is 8 minutes.

[0237] In this embodiment, the centrifugal speed in step (6) is 5000 rpm and the centrifugal time is 20 minutes.

[0238] In this embodiment, the final concentration of the medium-chain triglyceride in the system in step (8) is 5 wt %, and the mass ratio of the medium-chain triglyceride to sodium caseinate is 5:1.6.

[0239] In this embodiment, the high-pressure homogenization cycle parameter in step (9) is 30 MPa, and the number of cycles is 5 times.

[0240] In this embodiment, the sterilization temperature in step (10) is 95° C. and the sterilization time is 20 minutes.

[0241] Comparative Example 6

[0242] A method for preparing a purple sweet potato anthocyanin system that is stable at a water-oil interface comprises the following steps:

[0243] (1) Wash and peel fresh purple sweet potatoes, cut into pieces, and steam them in a steamer for 42 minutes. Then, blend them with water in a 1:1 mass ratio to obtain 780 g of purple sweet potato pulp;

[0244] (2) adding 9 g of amylase, 5 g of cellulase, and 6 g of glucoamylase to the purple sweet potato pulp in step (1);

[0245] (3) adding 15 g of a pH regulator to the purple sweet potato pulp in step (2) to adjust the pH value; wherein the pH regulator is a mixture of 0.1 mol / L citric acid solution and 0.1 mol / L sodium citrate solution, and the volume ratio of the citric acid solution to the sodium citrate solution is 1:10;

[0246] (4) starting enzymatic hydrolysis of the purple sweet potato pulp in step (3);

[0247] (5) inactivating the enzyme in the purple sweet potato pulp from step (4);

[0248] (6) centrifuging the purple sweet potato pulp from step (5) to obtain clarified purple sweet potato juice;

[0249] (7) adding 60 g of wheat oligopeptides, 90 g of maltitol, 4 g of sodium alginate and 20 g of salt to the purple sweet potato juice in step (6) to obtain purple sweet potato juice containing peptides, sugars and salts;

[0250] (8) Add 10 g of sucrose fatty acid ester to 50 g of medium chain triglyceride and mix well to obtain an oil phase mixture;

[0251] (9) The mixed solution in step (7) is added to the mixture in step (8), and a purple sweet potato anthocyanin system with a stable water-oil interface is obtained after high-pressure homogenization circulation.

[0252] (10) sterilizing the purple sweet potato anthocyanin system stabilized at the water-oil interface in step (9).

[0253] In this embodiment, the beater power in step (1) is 800W, and the beating time is 10 minutes.

[0254] In this embodiment, the pH value in step (3) is 5.5.

[0255] In this embodiment, the enzymatic hydrolysis temperature in step (4) is 45° C. and the enzymatic hydrolysis time is 3 hours.

[0256] In this embodiment, the enzyme inactivation temperature in step (5) is 88° C. and the enzyme inactivation time is 6 minutes.

[0257] In this embodiment, the centrifugal speed in step (6) is 5000 rpm and the centrifugal time is 20 minutes.

[0258] In this embodiment, the final concentration of the medium-chain triglyceride in the system in step (8) is 5 wt %, and the mass ratio of the medium-chain triglyceride to sucrose fatty acid ester is 5:1.0.

[0259] In this embodiment, the high-pressure homogenization cycle parameter in step (9) is 28 MPa, and the number of cycles is 5 times.

[0260] In this embodiment, the sterilization temperature in step (10) is 95° C. and the sterilization time is 20 minutes.

[0261] Performance test Thermal stability test

[0262] The systems obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were subjected to a thermal stability test: The systems obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were placed in a stoppered test tube and heated at a constant temperature of 80°C in a water bath. Samples were taken at 0, 30, 60, 90, and 120 minutes. The anthocyanin content of the purple sweet potato in the samples was detected by the pH differential method, and the retention rate and anthocyanin half-life were calculated. The thermal stability test results are shown in FIG. Figure 6 As shown in the figure, the anthocyanin degradation curve is as follows Figure 7 As shown. Figure 6It can be seen that after heat treatment, the anthocyanin retention rate of Example 1 reached 84.39%, Example 2 reached 82.14%, and Example 3 reached 86.23%, while the anthocyanin retention rates of Comparative Example 1 were 62.55%, Comparative Example 2 was 65.19%, Comparative Example 3 was 49.53%, Comparative Example 4 was 75.26%, Comparative Example 5 was 77.84%, and Comparative Example 6 was 79.44%.

[0263] The degradation rate constants and half-lives of anthocyanins in the thermal stability tests of the examples and comparative examples are shown in Table 1.

[0264] Table 1 Anthocyanin degradation rate constants and half-lives

[0265]

[0266] Table 1 shows that under the heat treatment conditions of Example 1, the half-life of anthocyanin in the obtained system is 497 minutes, and the k value is 0.001394 min. -1 ; Example 2 Under the conditions of heat treatment, the half-life of anthocyanins in the obtained system is 422 minutes, and the k value is 0.001644min -1 Example 3 Under heat treatment conditions, the anthocyanin half-life in the obtained system is 557 minutes, and the k value is 0.001245min -1 In comparative example 1, under heat treatment conditions, the half-life of anthocyanins in the obtained system was 178 minutes, and the k value was 0.003898min. -1 Comparative Example 2: Under heat treatment conditions, the anthocyanin half-life in the obtained system was 193 minutes, and the k value was 0.003587min -1 Comparative Example 3: Under heat treatment conditions, the anthocyanin half-life in the obtained system was 118 minutes, and the k value was 0.005884min -1 Comparative Example 4: Under heat treatment conditions, the anthocyanin half-life in the resulting system was 290 minutes, and the k value was 0.002388 min -1 Comparative Example 5: Under heat treatment conditions, the anthocyanin half-life in the resulting system was 330 minutes, and the k value was 0.0021min -1 Comparative Example 6: Under heat treatment conditions, the anthocyanin half-life in the obtained system was 363 minutes, and the k value was 0.001908min -1 ; The k values ​​of Examples 1 to 3 are all decreased compared to Comparative Examples 1 to 6, and the half-lives are all extended.

[0267] In the purple sweet potato anthocyanin system stabilized at the water-oil interface of the present invention, anthocyanin is dissolved in water and surrounded by medium-chain triglyceride (MCT) oil droplets, or it can be adsorbed at the oil-water interface. At the same time, the long-chain molecules of sodium alginate are adsorbed at the water-oil interface to form a protective layer. When the external temperature rises, this structure provides a physical barrier for anthocyanin. The oil droplet molecules around it are like small "insulation chambers" that provide a buffer for anthocyanin and reduce the degree of damage by high temperature. At the same time, high temperature will also affect the spontaneous oxidation of oils and fats. The saturated fatty acid-dominated oxidation resistance of MCT makes its oxidation degree at high temperature lower than that of soybean oil and corn oil. Anthocyanin itself is an antioxidant, and its oxidation stability in the system formed by MCT oil is higher than that of the other two oil systems. Therefore, the purple sweet potato anthocyanin retention rates in Examples 1 to 3 are much higher than those in Comparative Examples 1 to 6, indicating that the present invention has a certain protective effect on purple sweet potato anthocyanin.

[0268] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A purple sweet potato anthocyanin system with stable water-oil interface, characterized in that: Prepared from the following raw materials in parts by weight:

2. The water-oil interface-stabilized purple sweet potato anthocyanin system according to claim 1, characterized in that The mass ratio of the medium chain triglyceride to sodium caseinate is 5:0.8-1.2; The mass ratio of medium-chain triglycerides to phospholipids is 5:0.1-0.4; The mass ratio of medium chain triglycerides to Tween 60 is 5:0.4-0.

9.

3. The water-oil interface-stabilized purple sweet potato anthocyanin system according to claim 1 or 2, characterized in that The particle size of the oil particles in the purple sweet potato anthocyanin system with stable water-oil interface is 1.20 to 7.09 μm.

4. The water-oil interface-stabilized purple sweet potato anthocyanin system according to claim 1, characterized in that The pH adjuster includes citric acid and / or sodium citrate; The pH value of the purple sweet potato anthocyanin system stabilized at the water-oil interface is 5.5-6.

3.

5. The water-oil interface-stabilized purple sweet potato anthocyanin system according to claim 1, characterized in that The final concentration of the purple potato anthocyanin system stabilized by the wheat oligopeptide at the water-oil interface is 4 to 8 wt%; The final concentration of the purple potato anthocyanin system stabilized by the amylase at the water-oil interface is 0.8-1.0 wt %; The final concentration of the purple sweet potato anthocyanin system stabilized by the cellulase at the water-oil interface is 0.5-0.8 wt %; The final concentration of the purple sweet potato anthocyanin system stabilized by the glucoamylase at the water-oil interface is 0.4-0.8 wt %; The final concentration of the purple potato anthocyanin system stabilized by the medium-chain triglyceride at the water-oil interface is 5 to 8 wt%; The final concentration of the purple sweet potato anthocyanin system stabilized by maltitol at the water-oil interface is 8-10 wt%; The final concentration of the purple potato anthocyanin system stabilized by the salt at the water-oil interface is 1.5-2.5 wt %; The final concentration of the purple sweet potato anthocyanin system stabilized by sodium alginate at the water-oil interface is 0.2-0.5 wt %.

6. The method for preparing the water-oil interface-stabilized purple sweet potato anthocyanin system according to any one of claims 1 to 5, characterized in that: The following steps are involved: Mixing cooked purple sweet potatoes with water and beating them to obtain purple sweet potato pulp; The purple sweet potato pulp is mixed with amylase, cellulase, glucoamylase, and a pH regulator, and enzymatically hydrolyzed, inactivated, and centrifuged to obtain purple sweet potato juice; mixing the purple sweet potato juice with wheat oligopeptides, maltitol, sodium alginate and salt to obtain an aqueous phase mixture; Mixing medium chain triglycerides with sodium caseinate, phospholipids and Tween 60 to obtain an oil phase mixture; The aqueous phase mixture is mixed with the oil phase mixture, and high-pressure homogenization circulation is performed to obtain a purple sweet potato anthocyanin system with a stable water-oil interface.

7. The preparation method according to claim 6, characterized in that The cooked purple sweet potato is steamed; the steaming time is 40 to 45 minutes; After the purple sweet potato pulp is mixed with amylase, cellulase, glucoamylase and pH regulator, the pH value of the obtained mixed solution is 5.3-5.

8.

8. The preparation method according to claim 6, characterized in that The enzymatic hydrolysis temperature is 40-45°C and the time is 2.5-3h; The temperature of the enzyme inactivation treatment is 80-90° C., and the time is 5-10 minutes.

9. The preparation method according to claim 6, characterized in that The centrifugal speed is 5000-6000 rpm and the time is 15-20 min; The pressure of the high-pressure homogenization cycle is 28-34 MPa, and the number of cycles is 3-5 times.

10. Use of the water-oil interface-stable purple sweet potato anthocyanin system according to any one of claims 1 to 5 or the water-oil interface-stable purple sweet potato anthocyanin system prepared by the preparation method according to any one of claims 6 to 9 in the food field.

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