Preparation method of lycopene oil microcapsule

Abstract

The application discloses a preparation method of lycopene oil microcapsules, which comprises the following steps: mixing carboxymethyl konjac glucosan and modified konjac gum in equal quality to prepare a composite modified konjac gum, mixing the composite modified konjac gum with whey protein and beta-cyclodextrin to prepare a microcapsule wall material solution, mixing the microcapsule wall material solution, an emulsifier and lycopene oil, and reacting in a reaction kettle to obtain a product, and then performing high-speed homogenization, infrared-vacuum freeze drying and vacuum microwave treatment to remove water, so as to obtain the product. The wall material solution prepared by the formula has good antibacterial effect, the yield and embedding rate of lycopene oil are higher than those of traditional single wall material, the stability is better, and the wall material solution is suitable for constructing a lycopene delivery system and improving the bioavailability of lycopene.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food deep processing, and particularly relates to a lycopene oil microcapsule and a preparation method thereof. BACKGROUND

[0002] Lycopene is a liposoluble pigment belonging to carotenoids, and is one of the main carotenoids in human diet. Lycopene is a typical isoprene compound, and is most abundant in tomatoes, and is also relatively high in apricots, guavas, watermelons, papayas and pink grapefruits, and presents bright red. Lycopene contains 13 double bonds, of which 11 are conjugated double bonds. This structure enables lycopene to better scavenge active oxygen and quench singlet oxygen. However, the presence of unsaturated double bonds makes lycopene easily oxidized and isomerized under light, oxygen, acid, heat or other environmental changes, so that its spatial configuration is changed from the natural all-trans isomer to the cis isomer, thereby affecting its bioavailability. In addition, low water solubility and instability in the gastrointestinal tract result in low bioavailability of lycopene, thereby limiting its application in functional foods and health care products. Microencapsulation technology can well solve the problem of poor stability of lycopene and improve its bioavailability, including spray drying, freeze drying method, coacervation method, embedding complexation method, ion gelation method, etc. The types of encapsulating wall materials include sugars, proteins, proteins and sugars, etc.

[0003] In the prior art, a single wall material or a combination of multiple carbohydrates is used to prepare a wall material for embedding lycopene, and it is found that the embedding rate of the microcapsule is low and the stability is not high. The spray drying method for preparing lycopene oil microcapsules can realize batch continuous production, and the product has good dispersibility and solubility. However, the high temperature in the spray tower and the exposure of the microcapsules to air can easily inactivate the active substances. Freeze drying is widely used in the fields of food and medicine, and is mainly used for drying heat-sensitive substances, but it has high energy consumption, long drying time and high production cost. Konjac gum is a common embedding wall material for microcapsules. In the current research, due to its high viscosity, it needs to be modified to make it more suitable for embedding. Traditional modification often uses enzyme modification, and the modified konjac gum has single function and poor effect on delivering stable functional factors.

[0004] Therefore, it is necessary to develop a new method for modifying konjac gum and to use other wall materials to embed lycopene oil. At the same time, when drying the microcapsules, a new mode of using multiple drying methods to dry the materials can also promote the production of lycopene oil. SUMMARY

[0005] In view of the above shortcomings, in order to solve the problems of low stability of existing lycopene oil, single function after embedding and improve the bioavailability of lycopene, the application provides a preparation method of lycopene oil microcapsule and lycopene oil microcapsule prepared by the preparation method.

[0006] The microcapsule wall material comprises carboxymethyl konjac glucomannan, whey protein and beta-cyclodextrin; lycopene powder is dissolved in rapeseed oil as core material under high temperature conditions, and glycerol monolaurate is used as an emulsifier.

[0007] Konjac glucomannan can remove a part of acetyl groups under mild alkaline conditions, which is beneficial to the hydrogen bond crosslinking between intramolecular and intermolecular hydroxyl groups, and at the same time, the interaction between molecular chains is enhanced, thereby causing the change of film forming property. After the removal of acetyl groups, the molecular chain gradually changes from a semi-flexible linear molecule to an elastic microsphere, which is more suitable for being used as an embedding wall material than natural konjac glucomannan. At the same time, carboxymethyl konjac glucomannan has a certain antibacterial property and has a good inhibitory effect on bacteria.

[0008] The carbohydrate wall material has poor emulsifying ability due to no surface activity. By adding whey protein and beta-cyclodextrin to be compounded with carboxymethyl konjac glucomannan as the wall material of lycopene microcapsulation, the cost can be reduced, and the problems of poor protein solubility and poor emulsifying ability of carbohydrate substances can be solved. The synergistic effect of protein and carbohydrate substances on the physical properties of microcapsules is very helpful, and the stability of lycopene microcapsules can be greatly improved.

[0009] Glycerol monolaurate is synthesized by direct esterification of lauric acid and glycerol, and generally has the appearance of flaky or oily, white or light yellow fine crystalline particles. It is not only a good emulsifier, but also a safe, efficient and broad-spectrum antibacterial agent, and is not limited by pH. Under neutral or slightly alkaline conditions, it still has good antibacterial effect.

[0010] Infrared and vacuum freezing can improve the heat transfer mode and accelerate water sublimation. The infrared lamp is installed in the freeze dryer for vacuum freeze drying. After removing most of the water, the "skeleton" of the semi-dry product is formed. Then, the remaining water is removed by vacuum microwave method. The microwave penetrates the material quickly and efficiently, the radiant energy is converted into heat energy, the material is heated inside and outside at the same time, and the diffusion and evaporation of water are accelerated.

[0011] Specifically, the application is realized by the following technical means:

[0012] A preparation method of lycopene oil microcapsule, comprising the following steps:

[0013] (1) Carboxymethyl konjac glucosan and modified konjac gum are mixed at a mass ratio of 1:1 to obtain a composite modified konjac gum for standby use;

[0014] (2) The composite modified konjac gum is dissolved in hot distilled water under high-speed stirring, and then whey protein and β-cyclodextrin are added to prepare a microcapsule wall material solution for standby use;

[0015] (3) An emulsifier and lycopene oil are added to the microcapsule wall material solution, and the mixture is heated in a reaction kettle to obtain a first product;

[0016] (4) The first product is subjected to high-speed homogenization treatment, and then subjected to infrared-vacuum freeze drying to form a semi-dry product skeleton;

[0017] (5) The semi-dry product skeleton is subjected to vacuum microwave treatment to remove water, thereby obtaining lycopene oil microcapsules.

[0018] Further, the carboxymethyl konjac glucosan in step (1) is prepared by the following method:

[0019] 5-10 g of konjac powder is dispersed in 40-80 mL of 70% (v / v) ethanol aqueous solution, and then 4-8 g of sodium hydroxide is added, and electromagnetic stirring is performed at 50°C. After 1 hour, chloroacetic acid with a mass ratio of 1:1 of sodium hydroxide is added, and electromagnetic stirring is continued at 50°C for 2 h. The synthesized product is washed with 50% (v / v) ethanol aqueous solution until there is no residual chlorine in the filtrate, dehydrated by precipitation with anhydrous ethanol, and the solid on the filter paper is collected and dried at 50°C until the weight is constant. The product is ground and sieved to obtain carboxymethyl konjac glucosan.

[0020] Further, the modified konjac gum in step (1) is prepared by the following method:

[0021] Distilled water is placed in a magnetic stirrer with a 40°C water bath, 10 g of mannanase is added, the enzyme concentration is 6 U / g, 10 g of konjac gum powder is added and stirred uniformly, and then enzymolysis is performed at 40°C for 1 h. After the enzymolysis is completed, the enzyme is inactivated in a boiling water bath. The obtained product is dehydrated by anhydrous ethanol and dried at 50°C until the weight is constant. The product is ground and sieved to obtain modified konjac gum.

[0022] Further, the mass of the composite modified konjac gum in step (2) is 5%-20% of the mass of the wall material, the temperature of the hot distilled water is 40°C, and the mass of the whey protein and β-cyclodextrin is 80%-95% of the mass of the wall material.

[0023] Further, the mass ratio of the whey protein to β-cyclodextrin is 1:1.

[0024] Further, the emulsifier in step (3) is glycerol monolaurate, and the amount of the emulsifier used is 0.5%-2.5% of the mass of the microcapsule solution.

[0025] Further, the lycopene oil in step (3) is prepared by the following method:

[0026] Take 2g lycopene powder with 10% content and dissolve in 100g rapeseed oil, heat at 150-160℃ for 15-30s, then put in a reaction kettle, react at 170℃, 10MPa for 10-30min, cool and filter, then lycopene oil is obtained.

[0027] Further, the mass ratio of the microcapsule wall material solution to the lycopene oil in step (3) is 2-6:1.

[0028] Further, the water bath stirring condition under heating in step (3) is 40-60℃ water bath stirring for 0.5-2h.

[0029] Further, the high-speed homogenization treatment condition in step (4) is 10000-15000rpm / min for 1-5min.

[0030] The application further discloses the lycopene oil microcapsule prepared by any of the preparation methods.

[0031] The application has the following advantages:

[0032] 1. The carboxymethyl konjac glucomannan is used as the microcapsule wall material to embed the lycopene oil for the first time, and a novel microcapsule composite wall material is provided.

[0033] 2. The carboxymethyl-modified konjac glucomannan has certain antibacterial property, has a good inhibitory effect on bacteria, and the antibacterial diameter is up to 11cm, has a certain inhibitory effect on yeast but the effect is not obvious, and has no inhibitory effect on mold. The average antibacterial rate of the carboxymethyl konjac glucomannan on E. coli is 48.5%, and the average antibacterial rate on Staphylococcus aureus is 41.1%.

[0034] 3. The monolaurin is selected as the emulsifier, has good emulsifying property, is a safe, efficient and broad-spectrum antibacterial agent, and is not limited by pH, and has a good antibacterial effect under neutral or slightly alkaline conditions.

[0035] 4. The carboxymethyl konjac glucomannan, enzyme-modified konjac gum, whey protein and β-cyclodextrin are compounded, the yield and embedding rate are higher than those of a single wall material, the stability is better, and the system is suitable for constructing a lycopene delivery system and improving the bioavailability of lycopene. DETAILED DESCRIPTION

[0036] The application is described below in combination with examples, and the process parameters not specifically indicated can be referred to conventional techniques. The microcapsule wall material described in the application is composed of carboxymethyl konjac glucomannan, whey protein and β-cyclodextrin; lycopene powder is dissolved in rapeseed oil under high temperature conditions as the core material, and glycerol monolaurate is used as the emulsifier.

[0037] Example 1

[0038] A preparation method of lycopene oil microcapsules, comprising the following steps:

[0039] (1) Preparation of carboxymethyl konjac glucomannan:

[0040] 10 g of konjac powder is dispersed in 80 mL of 70% (v / v) ethanol aqueous solution, then 8 g of sodium hydroxide is added, and electromagnetic stirring is carried out at 50°C; after 1 hour, chloroacetic acid with a mass ratio of 1:1 of sodium hydroxide is added, and electromagnetic stirring is continued at 50°C for 2 h; the synthesized product is washed with 50% (v / v) ethanol aqueous solution until there is no residual chlorine in the filtrate, dehydrated by precipitation with anhydrous ethanol, the solid on the filter paper is collected, and dried at 50°C until the weight is constant, ground and sieved, to obtain carboxymethyl konjac glucomannan;

[0041] (2) Preparation of modified konjac gum:

[0042] Distilled water is placed in a magnetic stirrer with a 40°C water bath, 10 g of mannanase is added, the enzyme concentration is 6 U / g, 10 g of konjac gum powder is added after uniform stirring, and the mixture is uniformly mixed and enzymatically hydrolyzed at 40°C for 1 h; after the enzymatic hydrolysis is completed, the enzyme is inactivated in a boiling water bath; the obtained product is dehydrated by anhydrous ethanol and dried at 50°C until the weight is constant, ground and sieved, to obtain modified konjac gum.

[0043] (3) Preparation of composite modified konjac gum:

[0044] Carboxymethyl konjac glucomannan and modified konjac gum are mixed at a mass ratio of 1:1 to obtain composite modified konjac gum for standby use;

[0045] (4) Preparation of microcapsule wall material solution:

[0046] The composite modified konjac gum is dissolved in high-speed stirring in hot distilled water at 40°C, then whey protein and β-cyclodextrin with a mass ratio of 1:1 are added, which account for 90% of the mass of the wall material, to prepare a microcapsule wall material solution for standby use, and the mass of the composite modified konjac gum is 10% of the mass of the wall material;

[0047] (5) Preparation of lycopene oil:

[0048] Take 2 g of lycopene powder with a content of 10% in 100 g of rapeseed oil, heat at 120-150℃ for 30 s, then place in a reaction kettle, react at 170℃, 10 MPa for 15 min, cool and filter, and lycopene oil is obtained;

[0049] (6) Preparation of lycopene oil microcapsules:

[0050] Add 1% glycerol monolaurate as an emulsifier in the mass of the microcapsule solution to the microcapsule wall material solution, then add lycopene oil, the mass ratio of microcapsule wall material solution to lycopene oil is 6:1, stir in a water bath at 40℃ for 1h, then homogenize at a speed of 15000 rpm / min for 3 min, complete preliminary dehydration by infrared-vacuum freeze drying, and then remove all water by vacuum microwave treatment, and lycopene oil microcapsules are obtained.

[0051] Example 2

[0052] A method for preparing lycopene oil microcapsules, comprising the following steps:

[0053] (1) Preparation of carboxymethyl konjac glucomannan:

[0054] Disperse 10 g of konjac powder in 80 mL of 70% (v / v) ethanol aqueous solution, then add 8 g of sodium hydroxide, and perform electromagnetic stirring at 50℃; after 1 hour, add chloroacetic acid with a mass ratio of 1:1 of sodium hydroxide, and continue electromagnetic stirring at 50℃ for 2h; wash the synthesized product with 50% (v / v) ethanol aqueous solution until there is no residual chlorine in the filtrate, dehydrate by precipitation with anhydrous ethanol, collect the solid on the filter paper, dry at 50℃ until the weight is constant, grind and sieve, and carboxymethyl konjac glucomannan is obtained;

[0055] (2) Preparation of modified konjac gum:

[0056] Put distilled water into a magnetic stirrer with a water bath at 40℃, add 10 g of mannanase with an enzyme concentration of 6 U / g, stir uniformly, add 10 g of konjac gum powder, mix uniformly, and then perform enzymatic hydrolysis at 40℃ for 1h; after the enzymatic hydrolysis is completed, perform enzyme inactivation in a boiling water bath, dehydrate the obtained product with anhydrous ethanol, and dry at 50℃ until the weight is constant; grind and sieve, and modified konjac gum is obtained.

[0057] (3) Preparation of composite modified konjac gum:

[0058] Mix carboxymethyl konjac glucomannan and modified konjac gum according to a mass ratio of 1:1 to obtain composite modified konjac gum for later use;

[0059] (4) Preparation of microcapsule wall material solution:

[0060] The compound modified konjac gum is dissolved in 40℃ hot distilled water under high speed stirring, whey protein and β-cyclodextrin with a mass ratio of 1:1 are added, and the compound modified konjac gum accounts for 90% of the mass of the wall material, to prepare a wall material solution for standby, and the mass of the compound modified konjac gum is 10% of the mass of the wall material;

[0061] (5) Preparation of lycopene oil:

[0062] 2g lycopene powder with a content of 10% is dissolved in 100g rapeseed oil, heated at 150℃ for 30s, then placed in a reaction kettle, reacted at 170℃ and 10MPa for 15min, and then cooled and filtered to obtain lycopene oil;

[0063] (6) Preparation of lycopene oil microcapsules:

[0064] 1% glyceryl monolaurate is added to the microcapsule wall material solution as an emulsifier, and then lycopene oil is added, and the mass ratio of the microcapsule wall material solution to the lycopene oil is 6:1, and the solution is stirred in a water bath at 40℃ for 1h, then homogenized at a speed of 15000rpm / min for 3min, and then subjected to infrared-vacuum freeze drying to complete the preliminary dehydration, and then vacuum microwave treatment is used to remove all the water to obtain lycopene oil microcapsules.

[0065] Example 3

[0066] A method for preparing lycopene oil microcapsules, comprising the following steps:

[0067] (1) Preparation of carboxymethyl konjac glucomannan:

[0068] 10g konjac powder is dispersed in 80mL 70%(v / v) ethanol aqueous solution, then 8g sodium hydroxide is added, and electromagnetic stirring is carried out at 50℃; after 1h, chloroacetic acid with a mass ratio of 1:1 of sodium hydroxide is added, and electromagnetic stirring is continued at 50℃ for 2h; the synthesized product is washed with 50%(v / v) ethanol aqueous solution until there is no residual chlorine in the filtrate, dehydrated by precipitation with anhydrous ethanol, the solid on the filter paper is collected, and dried at 50℃ until the weight is constant, ground and sieved to obtain carboxymethyl konjac glucomannan;

[0069] (2) Preparation of modified konjac gum:

[0070] Distilled water is placed in a magnetic stirrer with a 40℃ water bath, 10g of mannanase is added, the enzyme concentration is 6U / g, 10g of konjac gum powder is added after stirring, and the mixture is uniformly stirred and enzymolysis is carried out at 40℃ for 1h; after the enzymolysis is completed, the enzyme is inactivated in a boiling water bath; the obtained product is dehydrated by anhydrous ethanol and dried at 50℃ until the weight is constant, ground and sieved to obtain modified konjac gum.

[0071] (3) Preparation of compound modified konjac gum:

[0072] Carboxymethyl konjac glucosan and modified konjac gum were mixed at a mass ratio of 1:1 to obtain a composite modified konjac gum for standby use;

[0073] (4) Preparation of microcapsule wall material solution:

[0074] The composite modified konjac gum was dissolved in 40℃ hot distilled water under high-speed stirring, and then whey protein and β-cyclodextrin were added at a mass ratio of 1:1, accounting for 90% of the mass of the wall material, to prepare a microcapsule wall material solution for standby use. The mass of the composite modified konjac gum was 10% of the mass of the wall material;

[0075] (5) Preparation of lycopene oil:

[0076] 2g of lycopene powder with a content of 10% was dissolved in 100g of rapeseed oil, heated at 150℃ for 30s, then placed in a reaction kettle, and reacted at 170℃ and 10MPa for 15min, and then cooled and filtered to obtain lycopene oil;

[0077] (6) Preparation of lycopene oil microcapsules:

[0078] Glyceryl monolaurate was added to the microcapsule wall material solution as an emulsifier at a mass ratio of 1% of the mass of the microcapsule solution, and then lycopene oil was added. The mass ratio of the microcapsule wall material solution to the lycopene oil was 6:1, and the mixture was stirred in a water bath at 40℃ for 1h, then homogenized at a speed of 15000rpm / min for 3min, and then subjected to infrared-vacuum freeze drying to complete the preliminary dehydration, and then vacuum microwave treatment was used to remove all the water to obtain lycopene oil microcapsules.

[0079] Comparative Example 1

[0080] Compared with Example 1, the use of carboxymethyl konjac glucosan was cancelled in the preparation of the microcapsule wall material solution, and the remaining steps were the same as those of Example 1, specifically:

[0081] (1) Preparation of modified konjac gum:

[0082] Distilled water was placed in a 40℃ water bath magnetic stirrer, 10g of mannanase was added, the enzyme concentration was 6U / g, and 10g of konjac gum powder was added under stirring, mixed uniformly, and then subjected to enzymolysis at 40℃ for 1h. After the enzymolysis was completed, the enzyme was inactivated in a boiling water bath. The obtained product was dehydrated with anhydrous ethanol and then dried at 50℃ to a constant weight. After grinding and sieving, the modified konjac gum was obtained for standby use;

[0083] (2) Preparation of microcapsule wall material solution:

[0084] Modified konjac gum was dissolved in hot distilled water at 40℃ with high speed stirring, then whey protein and β-cyclodextrin with a mass ratio of 1:1 were added, which accounted for 90% of the mass of the wall material, and a microcapsule wall material solution was prepared for standby, the mass of modified konjac gum was 10% of the mass of the wall material;

[0085] (3) Preparation of lycopene oil:

[0086] 2g lycopene powder with a content of 10% was dissolved in 100g rapeseed oil, heated at 150℃ for 30s, then placed in a reaction kettle, reacted at 170℃ and 10MPa for 15min, and then cooled and filtered to obtain lycopene oil;

[0087] (4) Preparation of lycopene oil microcapsules:

[0088] 1% glyceryl monolaurate was added to the microcapsule wall material solution as an emulsifier, and then lycopene oil was added, the mass ratio of microcapsule wall material solution to lycopene oil was 6:1, and the solution was stirred in a water bath at 40℃ for 1h, then homogenized at a speed of 15000rpm / min for 3min, and then subjected to infrared-vacuum freeze drying to complete the preliminary dehydration, and then vacuum microwave treatment was used to remove all the water to obtain lycopene oil microcapsules.

[0089] Comparative Example 2

[0090] Compared with Example 1, the use of modified konjac gum was cancelled in the preparation of the microcapsule wall material solution, and the rest of the steps were the same as in Example 1, specifically:

[0091] (1) Preparation of carboxymethyl konjac glucomannan:

[0092] 10g konjac powder was dispersed in 80mL 70%(v / v) ethanol aqueous solution, then 8g sodium hydroxide was added, and electromagnetic stirring was carried out at 50℃; after 1h, chloroacetic acid with a mass ratio of 1:1 to sodium hydroxide was added, and electromagnetic stirring was continued at 50℃ for 2h; the synthesized product was washed with 50%(v / v) ethanol aqueous solution until there was no residual chlorine in the filtrate, then dehydrated by precipitation with anhydrous ethanol, the solid on the filter paper was collected, and dried at 50℃ until the weight was constant, then ground and sieved to obtain carboxymethyl konjac glucomannan;

[0093] (2) Preparation of microcapsule wall material solution:

[0094] Carboxymethyl konjac glucomannan was dissolved in hot distilled water at 40℃ with high speed stirring, then whey protein and β-cyclodextrin with a mass ratio of 1:1 were added, which accounted for 90% of the mass of the wall material, and a microcapsule wall material solution was prepared for standby, the mass of carboxymethyl konjac glucomannan was 10% of the mass of the wall material;

[0095] (3) Preparation of lycopene oil:

[0096] Take 2 g content of 10% lycopene powder dissolved in 100 g rapeseed oil, heated at 150 ℃ for 30 s, then placed in a reaction kettle, reacted at 170 ℃, 10 MPa for 15 min, and then cooled and filtered to obtain lycopene oil;

[0097] (4) Preparation of lycopene oil microcapsules:

[0098] Add 1% glycerol monolaurate as an emulsifier to the microcapsule solution, then add lycopene oil, and the mass ratio of microcapsule wall material solution to lycopene oil is 6:1, stir in a water bath at 40 ℃ for 1 h, then homogenize at a speed of 15000 rpm / min for 3 min, complete preliminary dehydration by infrared-vacuum freeze drying, and then remove all water by vacuum microwave treatment to obtain lycopene oil microcapsules.

[0099] Comparative Example 3

[0100] Compared with Example 1, the use of whey protein is cancelled in the preparation of the microcapsule wall material solution, and the rest of the steps are the same as in Example 1, specifically:

[0101] (1) Preparation of carboxymethyl konjac glucomannan:

[0102] Disperse 10 g of konjac powder in 80 mL of 70% (v / v) ethanol aqueous solution, then add 8 g of sodium hydroxide, and perform electromagnetic stirring at 50 ℃; After 1 hour, add chloroacetic acid with a mass ratio of 1:1 of sodium hydroxide, and continue electromagnetic stirring at 50 ℃ for 2 h. The synthesized product is washed with 50% (v / v) ethanol aqueous solution until there is no residual chlorine in the filtrate, dehydrated by precipitation with anhydrous ethanol, collect the solid on the filter paper, and dry at 50 ℃ until the weight is constant, grind and sieve to obtain carboxymethyl konjac glucomannan;

[0103] (2) Preparation of modified konjac gum:

[0104] Put distilled water into a magnetic stirrer in a 40 ℃ water bath, add 10 g of mannanase with an enzyme concentration of 6 U / g, stir uniformly, add 10 g of konjac gum powder, mix uniformly, and then perform enzymatic hydrolysis at 40 ℃ for 1 h. After the enzymatic hydrolysis is completed, perform enzyme inactivation in a boiling water bath. The obtained product is dehydrated by anhydrous ethanol and dried at 50 ℃ until the weight is constant. Grind and sieve to obtain modified konjac gum.

[0105] (3) Preparation of composite modified konjac gum:

[0106] Mix carboxymethyl konjac glucomannan and modified konjac gum at a mass ratio of 1:1 to obtain composite modified konjac gum for use;

[0107] (4) Preparation of microcapsule wall material solution:

[0108] The complex modified konjac gum was dissolved in 40℃ hot distilled water under high speed stirring, then 90% of β-cyclodextrin by weight of the wall material was added to prepare a wall material solution for microcapsules, and the weight of the complex modified konjac gum was 10% of the wall material;

[0109] (5) Preparation of lycopene oil:

[0110] 2g of lycopene powder with a content of 10% was dissolved in 100g of rapeseed oil, heated at 150℃ for 30s, then placed in a reaction kettle, reacted at 170℃ and 10MPa for 15min, and then cooled and filtered to obtain lycopene oil;

[0111] (6) Preparation of lycopene oil microcapsules:

[0112] 1% of glycerol monolaurate by weight of the microcapsule solution was added to the microcapsule wall material solution as an emulsifier, then lycopene oil was added, and the mass ratio of the microcapsule wall material solution to the lycopene oil was 6:1, stirred in a water bath at 40℃ for 1h, then homogenized at a speed of 15000rpm / min for 3min, and then subjected to infrared-vacuum freeze drying to complete the preliminary dehydration, and then subjected to vacuum microwave treatment to remove all water to obtain lycopene oil microcapsules.

[0113] Comparative Example 4

[0114] Compared with Example 1, the use of β-cyclodextrin was cancelled in the preparation of the microcapsule wall material solution, and the rest of the steps were the same as in Example 1, specifically:

[0115] (1) Preparation of carboxymethyl konjac glucomannan:

[0116] 10g of konjac powder was dispersed in 80mL of 70%(v / v) ethanol aqueous solution, then 8g of sodium hydroxide was added, and electromagnetic stirring was carried out at 50℃; After 1h, chloroacetic acid with a mass ratio of 1:1 of sodium hydroxide was added, and electromagnetic stirring was continued at 50℃ for 2h; The synthesized product was washed with 50%(v / v) ethanol aqueous solution until there was no residual chlorine in the filtrate, then dehydrated by precipitation with anhydrous ethanol, the solid on the filter paper was collected, and dried at 50℃ until the weight was constant, then ground and sieved to obtain carboxymethyl konjac glucomannan;

[0117] (2) Preparation of modified konjac gum:

[0118] Distilled water was placed in a magnetic stirrer with a 40℃ water bath, 10g of mannanase was added, the enzyme concentration was 6U / g, 10g of konjac gum powder was added after stirring, and the mixture was uniformly stirred and enzymolysis was carried out at 40℃ for 1h; After the enzymolysis was completed, the enzyme was inactivated in a boiling water bath, and the obtained product was dehydrated by anhydrous ethanol and dried at 50℃ until the weight was constant, then ground and sieved to obtain modified konjac gum.

[0119] (3) Preparation of complex modified konjac gum:

[0120] The carboxymethyl konjac glucosan and the modified konjac gum were mixed at a mass ratio of 1:1 to obtain a composite modified konjac gum for standby use;

[0121] (4) Preparation of microcapsule wall material solution:

[0122] The composite modified konjac gum was dissolved in hot distilled water at 40°C under high-speed stirring, and then whey protein with a mass of 90% of the wall material was added to prepare a microcapsule wall material solution for standby use, and the mass of the composite modified konjac gum was 10% of the mass of the wall material.

[0123] (5) Preparation of lycopene oil:

[0124] 2 g of lycopene powder with a content of 10% was dissolved in 100 g of rapeseed oil, heated at 150°C for 30 s, and then placed in a reaction kettle, reacted at 170°C and 10 MPa for 15 min, and then cooled and filtered to obtain lycopene oil.

[0125] (6) Preparation of lycopene oil microcapsules:

[0126] Glyceryl monolaurate with a mass of 1% of the mass of the microcapsule solution was added as an emulsifier to the microcapsule wall material solution, and then lycopene oil was added, and the mass ratio of the microcapsule wall material solution to the lycopene oil was 6:1. The mixture was stirred in a water bath at 40°C for 1 h, and then homogenized at a speed of 15000 rpm / min for 3 min. The preliminary dehydration was completed by infrared-vacuum freeze drying, and then vacuum microwave treatment was performed to remove all the water to obtain lycopene oil microcapsules.

[0127] Test Example 1

[0128] The embedding rate, antibacterial effect, and lycopene loss rate of the products in each group after high-temperature treatment were determined

[0129] The yield of Example 1 was 85.42±1.60%, the embedding rate was 90.16±0.08%, the maximum antibacterial diameter against bacteria was 9 cm, the yeast was inhibited to a certain extent, the average antibacterial rate against Staphylococcus aureus was 40.69%, the microcapsules had good pH stability in acidic conditions, and the lycopene loss rate was 16.25% after treatment at 60°C for 8 h.

[0130] The yield of Comparative Example 1 was 71.03±2.10%, the embedding rate was 86.16±1.58%, the antibacterial diameter against bacteria was 4 cm, the yeast was inhibited to a certain extent, the average antibacterial rate against Staphylococcus aureus was 29.6%, and the lycopene loss rate was 20.10% after the microcapsules were treated at 60°C for 8 h.

[0131] The yield of the comparative example 2 is 68.23±2.48%, the embedding rate is 74.16±1.28%, the antibacterial diameter is 8 cm, the yeast is inhibited to a certain extent, the average antibacterial rate of Staphylococcus aureus is 39.76%, and the loss rate of lycopene is 18.14% after the microcapsules are treated at 60℃ for 8 h.

[0132] The yield of the comparative example 3 is 65.48±1.25%, the embedding rate is 60.4±2.1%, the antibacterial diameter is 8 cm, the yeast is inhibited to a certain extent, the average antibacterial rate of Staphylococcus aureus is 41.2%, and the loss rate of lycopene is 26.31% after the microcapsules are treated at 60℃ for 8 h.

[0133] The yield of the comparative example 4 is 42.6±1.3%, the embedding rate is 16.16±1.28%, the antibacterial diameter is 3 cm, the yeast is inhibited to a certain extent, the average antibacterial rate of Staphylococcus aureus is 12.8%, and the loss rate of lycopene is 60.14% after the microcapsules are treated at 60℃ for 8 h.

[0134] Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be defined by the claims.

Claims

1. A method for preparing lycopene oil microcapsules, characterized in that, The preparation method includes the following steps: (1) Mix carboxymethyl konjac glucoside and modified konjac gum at a mass ratio of 1:1 to obtain composite modified konjac gum for later use. (2) The composite modified konjac gum was dissolved in hot distilled water by high-speed stirring, and then whey protein and β-cyclodextrin were added to prepare a microcapsule wall material solution for later use. (3) Add emulsifier and lycopene oil to the microcapsule wall material solution, heat and stir in a reaction vessel to obtain the first product; (4) The first product is subjected to high-speed homogenization and then infrared-vacuum freeze drying to form a semi-dry product skeleton; (5) The semi-dry product skeleton is treated with vacuum microwave to remove moisture, thus obtaining lycopene oil microcapsules. The modified konjac gum mentioned in step (1) is prepared by the following method: Distilled water was placed in a magnetic stirrer in a 40°C water bath. A measured amount of mannanase with an enzyme concentration of 4-6 U / g was added and stirred until homogeneous. A measured amount of konjac gum powder was then added and mixed evenly. The mixture was then enzymatically hydrolyzed at 40°C for 1 hour. After the enzymatic hydrolysis was completed, the enzyme was inactivated by boiling water. The resulting product was dehydrated with anhydrous ethanol and dried at 50°C to constant weight. The product was then ground and sieved to obtain modified konjac gum. In step (2), the mass of the composite modified konjac gum is 5%-20% of the wall material mass, and the temperature of the hot distilled water is 40℃. The whey protein and β-cyclodextrin constitute 80%-95% of the wall material mass, and the mass ratio of whey protein to β-cyclodextrin is 1:

1.

2. The preparation method according to claim 1, characterized in that: The carboxymethyl konjac glucomannan mentioned in step (1) is prepared by the following method: Disperse 5-10g of konjac flour in 40-80mL of 70% v / v ethanol aqueous solution, then add 4-8g of sodium hydroxide and stir electromagnetically at 50℃. After 1 hour, add chloroacetic acid with a sodium hydroxide mass ratio of 1:1 and continue stirring electromagnetically at 50℃ for 2 hours. Wash the synthesized product with 50% v / v ethanol aqueous solution until there is no residual chlorine in the filtrate. Dehydrate by precipitation with anhydrous ethanol, collect the solid on filter paper, dry at 50℃ until the weight is constant, grind and sieve to obtain carboxymethyl konjac glucomannan.

3. The preparation method according to claim 1, characterized in that: The lycopene oil mentioned in step (3) is prepared by the following method: Dissolve 2g of 10% lycopene powder in 100g of rapeseed oil, heat at 150-160℃ for 15-30s, then place in a reaction vessel and react at 170℃ and 10MPa for 10-30min. After cooling and filtration, lycopene oil is obtained.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the microcapsule wall material solution to lycopene oil in step (3) is 2~6:1; The heating and stirring conditions are: stirring in a water bath at 40~60℃ for 0.5~2 hours.

5. The preparation method according to claim 1, characterized in that: The conditions for the high-speed homogenization process in step (4) are: processing at a speed of 10,000-15,000 rpm for 1-5 minutes.

6. A lycopene oil microcapsule prepared by the preparation method according to any one of claims 1 to 5.