阅读说明：本技术 一种用于烘焙食品的防腐剂脂质体及其制备方法 (Preservative liposome for baked food and preparation method thereof ) 是由 孟永宏 杨璐 郭建琦 牛永洁 于 2021-07-19 设计创作，主要内容包括：本发明涉及一种用于烘焙食品的防腐剂脂质体及其制备方法。该防腐剂脂质体是由防腐剂、磷脂、胆固醇、乳化剂、抗氧化剂与冻干保护剂组成的。本发明采用磷脂和胆固醇为壁材形成类脂质双分子膜,将防腐剂包封其中形成微型囊泡,有效隔离防腐剂与烘焙食品中酵母的直接接触,防止防腐剂对酵母的发酵影响,提高防腐剂的防腐效果,延长食品货架期。(The invention relates to a preservative liposome for baked food and a preparation method thereof. The preservative liposome consists of a preservative, phospholipid, cholesterol, an emulsifier, an antioxidant and a freeze-drying protective agent. According to the invention, phospholipid and cholesterol are used as wall materials to form a lipid bilayer membrane, and the preservative is encapsulated to form a micro vesicle, so that the preservative is effectively isolated from being in direct contact with yeast in the baked food, the fermentation influence of the preservative on the yeast is prevented, the preservative effect of the preservative is improved, and the shelf life of the food is prolonged.)

1. A preservative liposome for baked food, which is characterized by comprising the following components: in parts by weight

2. The preservative liposome according to claim 1, characterized in that it consists of: in parts by weight

3. Preservative liposome according to claim 1 or 2, characterized in that the preservative is one or more preservatives selected from sorbic acid, potassium sorbate, sodium propionate, calcium propionate or sodium dehydroacetate.

4. The preservative liposome according to claim 1 or 2, characterized in that the phospholipid is one or more phospholipids selected from the group consisting of egg yolk lecithin, hydrogenated egg yolk lecithin, soybean lecithin, hydrogenated soybean lecithin, sphingomyelin, phosphatidylethanolamine, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, distearoylphosphatidylcholine, dioleoylphosphatidylcholine or dilauroylphosphatidylcholine.

5. The liposome of claim 1 or 2, wherein the emulsifier is one or more emulsifiers selected from the group consisting of sucrose fatty acid ester, alkyl polyglycoside, sorbitan monooleate, distilled glyceryl monostearate, monolaurin, diacetyl tartaric acid ester of mono-and diglycerides, polyglyceryl fatty acid ester, sodium stearoyl lactylate, calcium stearoyl lactylate, fatty acid monoglyceride, fatty acid diglyceride, and polysorbate.

6. Preservative liposome according to claim 1 or 2, characterized in that the antioxidant is one or more antioxidants selected from the group consisting of vitamin E, tea polyphenols, rosemary extract or ascorbyl palmitate.

7. Preservative liposome according to claim 1 or 2, characterized in that the lyoprotectant is one or more lyoprotectants selected from trehalose, lactose, beta-cyclodextrin, dextran 40, povidone K24, water soluble starch, glucose, mannose, fructose, sucrose, mannitol, sorbitol or oligosaccharides.

8. The method for preparing preservative liposome according to claim 1, characterized in that the preparation method comprises the following steps:

A. dissolving sorbic acid preservative, 0.6-1.2 parts by weight of phospholipid, 0.2-0.8 part by weight of cholesterol, 0.01-0.06 part by weight of emulsifier and 0.001-0.020 part by weight of antioxidant in 50-100 parts by weight of chloroform and diethyl ether according to the volume ratio of 1: 1-9 in a mixed solvent;

B. dissolving one or more preservatives selected from potassium sorbate, sodium propionate, calcium propionate or sodium dehydroacetate in 10-50 parts by weight of phosphate buffer solution with pH 4.0-8.0 and concentration of 0.01-0.04 mol/L; the total amount of the sorbic acid and one or more preservatives selected from potassium sorbate, sodium propionate, calcium propionate or sodium dehydroacetate is 0.1-0.8 weight part;

C. mixing the solution obtained in the step A with the solution obtained in the step B, performing ultrasonic treatment to obtain a water-in-oil emulsion, and performing reduced pressure rotary evaporation for 10-30 min at the temperature of 20-40 ℃ and the rotating speed of 60-100 r/min to remove the solvent;

D. according to the volume ratio of the emulsion to the phosphate buffer solution of 1: 0.5 to 2.0; c, adding the phosphate buffer solution into the gel-state substance obtained in the step C, uniformly mixing, carrying out hydration treatment for 2-4 h at the temperature of 20-30 ℃, and then filtering by using a 0.45-micrometer filter membrane;

E. and D, pre-freezing the filtrate obtained in the step D at the temperature of minus 80 ℃ for 12 hours, adding 0.08-0.20 part by weight of a freeze-drying protective agent, and carrying out vacuum freeze-drying to obtain the preservative liposome.

9. The preparation method according to claim 8, wherein in the step C, ultrasonic treatment is performed for 4-8 min by using an ultrasonic device under the conditions of 40KHz frequency and 250W power.

10. The preparation method according to claim 8, wherein in the step E, the vacuum freeze-drying is performed for 20-26 hours under the conditions of the vacuum degree of 1.3-5.0 Pa and the temperature of-10 to-50 ℃.

[ technical field ] A method for producing a semiconductor device

The invention belongs to the technical field of food processing. More specifically, the present invention relates to a preservative liposome for baked food and to a method for preparing the preservative liposome.

[ background of the invention ]

Preservatives approved in national standard for food safety food additives approved in national standard for use in baked food such as bread are sorbic acid and potassium salts thereof, propionic acid and sodium salts thereof, calcium salts thereof, dehydroacetic acid and sodium salts thereof, and the like. The preservative is added into baked food such as bread or cake prepared by yeast fermentation process to protect the food from or reduce the pollution of microorganism (bacteria or fungi), and prolong the shelf life of the food. However, these preservatives can inhibit not only the contamination and growth of bacteria and fungi in food, but also the fermentation action of microorganisms (yeast), thereby causing a contradiction between fermentation and preservation and affecting the quality of baked goods such as bread and cakes.

CN201310091530.7 and CN202010203920.9 disclose a food preservative and a preparation method thereof, wherein, monoglyceride, diglyceride, medium chain triglyceride, lecithin, beeswax, hydrogenated oil and other wall materials are used to embed sodium sorbate, potassium sorbate, sodium dehydroacetate, sorbic acid and other preservatives to prepare a novel preservative; CN201610965347.9 discloses a microcapsule-embedded bread preservative and a preparation method thereof, wherein at least one preservative selected from distilled glyceryl monostearate, sorbitan monooleate, hydrogenated vegetable oil, monoglyceride laurate, diacetyl tartaric acid ester of mono-and diglycerides, polyglycerol fatty acid ester, sodium stearoyl lactylate and calcium stearoyl lactylate is embedded into at least one preservative selected from dehydroacetic acid, e-polylysine and calcium propionate to prepare the microcapsule-embedded bread preservative. The preservative granules produced in these applications can be kept out of contact with bread, so that the effect of the preservative on yeast fermentation can be avoided. Moreover, the preservative particles produced by the preservative manufacturing methods disclosed in these applications are relatively large, and the larger the preservative particles are, the more non-uniform the distribution thereof and the poorer the preservative effect, and the preservative effect is the best only when the preservative particles are uniformly distributed in the fermentation system thereof, at the same preservative addition level.

Based on the summary of the prior art, the present inventors have conducted a great deal of experimental research and analytical summary aiming at the defects of the prior art, and finally completed the present invention.

[ summary of the invention ]

[ problem to be solved ]

The invention aims to provide a preservative liposome for baked food.

Another object of the present invention is to provide a method for preparing the preservative liposome for baked food.

[ solution ]

The invention is realized by the following technical scheme.

The invention relates to a preservative liposome for baked food.

The preservative liposome consists of the following components: in parts by weight

According to a preferred embodiment of the invention, the preservative liposome is composed of: in parts by weight

According to another preferred embodiment of the invention, the preservative is one or more preservatives selected from sorbic acid, potassium sorbate, sodium propionate, calcium propionate or sodium dehydroacetate.

According to another preferred embodiment of the present invention, the phospholipid is one or more phospholipids selected from the group consisting of egg yolk lecithin, hydrogenated egg yolk lecithin, soybean lecithin, hydrogenated soybean lecithin, sphingomyelin, phosphatidylethanolamine, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, distearoylphosphatidylcholine, dioleoylphosphatidylcholine and dilauroylphosphatidylcholine.

According to another preferred embodiment of the invention, the emulsifier is one or more emulsifiers selected from sucrose fatty acid esters, alkyl polyglycosides, sorbitan monooleate, distilled glyceryl monostearate, monoglyceride laurate, diacetyl tartaric acid esters of mono-and diglycerides, polyglycerol fatty acid esters, sodium stearoyl lactylate and calcium stearoyl lactylate, fatty acid monoglycerides, fatty acid diglycerides or polysorbates.

According to another preferred embodiment of the present invention, the antioxidant is one or more antioxidants selected from the group consisting of vitamin E, tea polyphenol, rosemary extract or ascorbyl palmitate.

According to another preferred embodiment of the present invention, the lyoprotectant is one or more lyoprotectants selected from trehalose, lactose, beta-cyclodextrin, dextran 40, povidone K24, water-soluble starch, glucose, mannose, fructose, sucrose, mannitol, sorbitol, and oligosaccharides.

The invention also relates to a preparation method of the preservative liposome.

The preparation method comprises the following preparation steps:

A. dissolving sorbic acid preservative, 0.6-1.2 parts by weight of phospholipid, 0.2-0.8 part by weight of cholesterol, 0.01-0.06 part by weight of emulsifier and 0.001-0.020 part by weight of antioxidant in 50-100 parts by weight of chloroform and diethyl ether according to the volume ratio of 1: 1-9 in a mixed solvent;

B. dissolving one or more preservatives selected from potassium sorbate, sodium propionate, calcium propionate or sodium dehydroacetate in 10-50 parts by weight of phosphate buffer solution with pH 4.0-8.0 and concentration of 0.01-0.04 mol/L; the total amount of the sorbic acid and one or more preservatives selected from potassium sorbate, sodium propionate, calcium propionate or sodium dehydroacetate is 0.1-0.8 weight part;

C. mixing the solution obtained in the step A with the solution obtained in the step B, performing ultrasonic treatment to obtain a water-in-oil emulsion, and performing reduced pressure rotary evaporation for 10-30 min at the temperature of 20-40 ℃ and the rotating speed of 60-100 r/min to remove the solvent;

D. according to the volume ratio of the emulsion to the phosphate buffer solution of 1: 0.5 to 2.0; c, adding the phosphate buffer solution into the gel-state substance obtained in the step C, uniformly mixing, carrying out hydration treatment for 2-4 h at the temperature of 20-30 ℃, and then filtering by using a 0.45-micrometer filter membrane;

E. and D, pre-freezing the filtrate obtained in the step D at the temperature of minus 80 ℃ for 12 hours, adding 0.08-0.20 part by weight of a freeze-drying protective agent, and carrying out vacuum freeze-drying to obtain the preservative liposome.

According to a preferred embodiment of the present invention, in step C, ultrasonic treatment is performed for 4-8 min by using an ultrasonic device under the conditions of 40KHz frequency and 250W power.

According to another preferred embodiment of the invention, in the step E, vacuum freeze drying is carried out for 20-26 h under the conditions of the vacuum degree of 1.3-5.0 Pa and the temperature of-10 to-50 ℃.

The present invention will be described in more detail below.

The invention relates to a preservative liposome for baked food.

The preservative liposome consists of the following components: in parts by weight

According to the invention, a preservative liposome is understood to be a liposome which comprises phospholipids and cholesterol together forming the liposome base material and encapsulating preservatives and other components.

According to the invention, the main functions of the preservative in the preservative liposome are to prevent the growth of microorganisms, prevent food from putrefaction and deterioration and prolong the storage period of food;

the preservative used in the present invention is one or more preservatives selected from sorbic acid, potassium sorbate, sodium propionate, calcium propionate or sodium dehydroacetate, which are all currently marketed products such as sorbic acid sold under the trade name sorbic acid by southeast acetic acid chemical company, ltd, sodium propionate sold under the trade name sodium propionate by food ingredients, ltd, picnoconkontinus, and sodium dehydroacetate sold under the trade name sodium dehydroacetate by food ingredients, ltd, piconkonnoconken.

The phospholipid structure is one phosphate group and one quaternaryAmmonium saltsHydrophilicity of radical compositionRadical (I)And by two longerHydrocarbons Base ofA constituent lipophilic group. The main function of the phospholipid in the preservative liposome is to embed the wall material of the preservative to form a bilayer membrane embedded preservative;

the phospholipid used in the present invention is one or more phospholipids selected from the group consisting of egg yolk lecithin, hydrogenated egg yolk lecithin, soybean lecithin, hydrogenated soybean lecithin, sphingomyelin, phosphatidylethanolamine, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, distearoylphosphatidylcholine, dioleoylphosphatidylcholine or dilauroylphosphatidylcholine. These phospholipids are currently marketed products such as egg yolk lecithin sold under the trade name egg yolk lecithin by the widely sourced biotechnology limited of sienna, phosphatidylethanolamine sold under the trade name 1, 2-distearoyl-sn-glycerophosphatidylethanolamine by the pharmaceutical company limited of southeast sourdough, su, distearoyl phosphatidylcholine sold under the trade name 1, 2-distearoyl-sn-glycerophosphatidylcholine by the pharmaceutical company limited of southeast, su.

According to the invention, the main functions of cholesterol in the preservative liposome are to increase the fluidity of a phospholipid bilayer membrane, reduce the membrane permeability, reduce the permeability of a core material and protect phospholipid from being oxidized;

the cholesterol used in the present invention is a currently marketed product, such as the cholesterol product sold under the trade name cholesterol by the Angel chemical technology Limited in Anhui.

According to the invention, the main role of the emulsifier in the preservative liposomes is to improve the surface tension between the various constituent phases in the emulsion, forming a homogeneous dispersion or emulsion;

the emulsifier used in the present invention is one or more emulsifiers selected from sucrose fatty acid esters, alkyl polyglycosides, sorbitan monooleate, distilled glyceryl monostearate, monoglyceride laurate, diacetyl tartaric acid esters of mono-and diglycerides, polyglycerol fatty acid esters, sodium stearoyl lactylate and calcium stearoyl lactylate, mono-and diglycerides or polysorbates. These emulsifiers are commercially available products, such as sucrose fatty acid ester sold under the trade name sucrose fatty acid ester by Guangxi high-pass food science and technology Co., Ltd, diacetyl tartaric acid ester of mono-diglyceride sold under the trade name diacetyl tartaric acid ester of Monodiglyceride by Zhengzhou hongxiang chemical products Co., Ltd, and mono-and diglycerides sold under the trade name monoglycerol ester of fatty acid by Jialishi additive (Haian) Co., Ltd.

According to the invention, the main function of the antioxidant in the preservative liposome is to prevent or delay the oxidative decomposition and deterioration of grease or food ingredients and improve the food stability;

the antioxidant used in the present invention is one or more antioxidants selected from the group consisting of vitamin E, tea polyphenol, rosemary extract or ascorbyl palmitate. These antioxidants are commercially available products such as vitamin E sold under the trade name mixed tocopherol by Shaanxi Haishi Sff bioengineering Co., Ltd, tea polyphenol sold under the trade name tea polyphenol by Jiangxi Congtian Biotech Co., Ltd, ascorbyl palmitate sold under the trade name L-ascorbyl palmitate (enzyme method) by Hebei Xingrun food science Co., Ltd.

According to the invention, the main functions of the freeze-drying protective agent in the preservative liposome are to ensure that the freeze-drying process is smoothly carried out, reduce the shrinkage of a sample, improve the freeze-drying rate and shorten the freeze-drying time;

the freeze-drying protective agent used in the invention is one or more freeze-drying protective agents selected from trehalose, lactose, beta-cyclodextrin, dextran 40, povidone K24, water-soluble starch, glucose, mannose, fructose, sucrose, mannitol, sorbitol or oligosaccharide. These lyoprotectants are currently marketed products such as trehalose sold under the trade name trehalose by Shaanxi Waqi pharmaceutic adjuvants, Inc., beta-cyclodextrin sold under the trade name beta-cyclodextrin by hong ji biol, Inc., of Mengzhou, and Povidone K24 sold under the trade name Povidone K24 by Shaanxi Waqi pharmaceutic adjuvants, Inc.

In the present invention, when the contents of the phospholipid, cholesterol, emulsifier, antioxidant and lyoprotectant are within the above-mentioned ranges, if the content of the preservative is less than 0.1 parts by weight, the content of the effective ingredient, i.e., the preservative, in the product is too low; if the content of the preservative is more than 0.8 parts by weight, the encapsulation efficiency of the product may be reduced; therefore, it is reasonable that the content of the preservative is 0.1 to 0.8 parts by weight, preferably 0.2 to 0.6 parts by weight;

likewise, when the contents of the preservative, cholesterol, emulsifier, antioxidant and lyoprotectant are within the above-mentioned ranges, if the content of the phospholipid is less than 0.6 parts by weight, the encapsulation efficiency of the product may be reduced; if the content of the phospholipid is more than 1.2 parts by weight, the content of the effective component, namely the preservative, in the product is too low; therefore, the content of the phospholipid is reasonably 0.6 to 1.2 parts by weight, preferably 0.8 to 1.0 part by weight;

when the contents of the preservative, phospholipid, emulsifier, antioxidant and lyoprotectant are within the above-mentioned ranges, if the content of cholesterol is less than 0.2 parts by weight, the antioxidant and physical stability of the liposome decreases; if the content of cholesterol is more than 0.8 parts by weight, the load of the phospholipid bilayer membrane is exceeded, increasing the hydrophilicity of the membrane, resulting in liposome rupture; therefore, it is reasonable that the content of cholesterol is 0.2 to 0.8 part by weight, preferably 0.3 to 0.6 part by weight;

when the contents of the preservative, the phospholipid, the cholesterol, the antioxidant and the lyoprotectant are within the above ranges, if the content of the emulsifier is less than 0.01 part by weight, an emulsification system is not easily formed and the system is unstable; if the content of the emulsifier is higher than 0.06 part by weight, the phospholipid is dissolved in the mixed micelle in which the emulsifier and the saturated vesicle coexist, the membrane fluidity and the permeability are enhanced, and the core material leaks; therefore, it is reasonable that the content of the emulsifier is 0.01 to 0.06 part by weight, preferably 0.02 to 0.05 part by weight;

when the contents of the preservative, the phospholipid, the cholesterol, the emulsifier and the freeze-drying protective agent are in the range, if the content of the antioxidant is lower than 0.001 weight part, a good antioxidation effect cannot be realized, and the encapsulation rate of the liposome is reduced; if the content of the antioxidant is higher than 0.020 part by weight, the antioxidant effect can not be well achieved, and the entrapment rate of the liposome is reduced; therefore, it is reasonable that the content of the antioxidant is 0.001 to 0.020 parts by weight, preferably 0.006 to 0.015 parts by weight;

when the contents of the preservative, the phospholipid, the cholesterol, the emulsifier and the antioxidant are within the range, if the content of the freeze-drying protective agent is less than 0.08 weight part, the product stability is reduced, and phenomena such as shrinkage, cracking and the like occur; if the content of the lyoprotectant is more than 0.20 parts by weight, the raw materials are wasted; therefore, the content of the lyoprotectant is 0.08 to 0.20 parts by weight, preferably 0.10 to 0.18 parts by weight;

preferably, the preservative liposome is composed of the following components: in parts by weight

The invention also relates to a preparation method of the preservative liposome.

The preparation method comprises the following preparation steps:

A. dissolving sorbic acid preservative, 0.6-1.2 parts by weight of phospholipid, 0.2-0.8 part by weight of cholesterol, 0.01-0.06 part by weight of emulsifier and 0.001-0.020 part by weight of antioxidant in 50-100 parts by weight of chloroform and diethyl ether according to the volume ratio of 1: 1-9 in a mixed solvent;

B. dissolving one or more preservatives selected from potassium sorbate, sodium propionate, calcium propionate or sodium dehydroacetate in 10-50 parts by weight of phosphate buffer solution with pH 4.0-8.0 and concentration of 0.01-0.04 mol/L; the total amount of the sorbic acid and one or more preservatives selected from potassium sorbate, sodium propionate, calcium propionate or sodium dehydroacetate is 0.1-0.8 weight part;

the preservatives, phospholipids, cholesterol, emulsifiers and antioxidants have been described above and are therefore not described in detail here.

C. Mixing the solution obtained in the step A with the solution obtained in the step B, performing ultrasonic treatment to obtain a water-in-oil emulsion, and performing reduced pressure rotary evaporation for 10-30 min at the temperature of 20-40 ℃ and the rotating speed of 60-100 r/min to remove the solvent;

in the step, ultrasonic treatment is carried out for 4-8 min by using ultrasonic equipment under the conditions of 40KHz frequency and 250W power.

In the present invention, when the frequency and the ultrasonic power of the ultrasonic wave are within the above ranges, if the ultrasonic treatment time is shorter than 4min, a stable emulsification system is not formed; if the ultrasonic treatment time is longer than 8min, the structure of the liposome is damaged, the liposome is broken, and the entrapment rate is reduced; therefore, the ultrasonic treatment time is preferably 4-8 min, preferably 5-6 min;

the ultrasonic apparatus used in the present invention is a product currently marketed, for example, by Kunshan Seama ultrasonic Instrument Co., Ltd under the trade name KH-250DB type numerically controlled ultrasonic cleaner.

And carrying out reduced pressure rotary evaporation on the water-in-oil emulsion obtained by ultrasonic treatment for 10-30 min at the temperature of 20-40 ℃ and the rotating speed of 60-100 r/min to remove the solvent.

In the present invention, when the rotation speed and the reduced pressure rotary evaporation time are in the range, if the temperature of the reduced pressure rotary evaporation is lower than 20 ℃, the solvent cannot be quickly and effectively evaporated to form a gel-state substance; if the temperature of the reduced-pressure rotary evaporation is higher than 40 ℃, gel-state substances formed in the later period are not easy to hydrate, the structure of the liposome is damaged, and the liposome is shrunk and cracked; therefore, the temperature of the reduced pressure rotary evaporation is suitably 20 to 40 ℃, preferably 26 to 34 ℃;

when the temperature of the reduced pressure rotary evaporation and the time of the reduced pressure rotary evaporation are in the range, if the rotating speed is lower than 60r/min, the solvent cannot be quickly and effectively evaporated to form a gel-state substance; if the rotating speed is higher than 100r/min, the structure of the liposome is damaged, and the liposome is broken; therefore, a rotation speed of 60 to 100r/min is appropriate, preferably 70 to 90 r/min;

when the temperature and the rotating speed of the reduced pressure rotary evaporation are in the range, if the reduced pressure rotary evaporation time is shorter than 10min, the solvent can not be completely evaporated, and a gel-state substance is formed; if the reduced-pressure rotary evaporation time is longer than 30min, the formed gel-state substance is not easy to hydrate and wastes the energy of a machine; therefore, the reduced pressure rotary evaporation time is suitably 10 to 30min, preferably 16 to 24 min;

the reduced-pressure rotary evaporation apparatus used in the present invention is an apparatus for continuously distilling a volatile solvent under reduced pressure, and is a product currently marketed, for example, by Shanghai Yangrong Biochemical Instrument factory company under the trade name RE-2000A rotary evaporator.

According to the odor smelling method (specifically, the bottle stopper is opened, the bottle mouth is separated from the nostril at about 0.5 m from the front lower part, the bottle mouth is gently fanned by hands, so that a very small amount of gas flows into the nostril), the odor of the solvent emitted by the residual liquid of the reduced pressure rotary evaporation is not smelled, and the solvent is considered to be completely removed, and the reduced pressure rotary evaporation is finished.

D. According to the volume ratio of the emulsion to the phosphate buffer solution of 1: 0.5 to 2.0; c, adding the phosphate buffer solution into the gel-state substance obtained in the step C, uniformly mixing, carrying out hydration treatment for 2-4 h at the temperature of 20-30 ℃, and then filtering by using a 0.45-micrometer filter membrane;

in this step, the hydration treatment is understood to be a combination reaction of the gel-state substance obtained in step C with water.

Adding phosphate buffer solution into the gel-state substance mainly aims at hydrating the gel-state substance to form milky liposome suspension; if the volume ratio of the gel-state substance to the phosphate buffer is more than 1: 0.5, the gel state substance can not be fully hydrated and fall off; if the volume ratio of the emulsion to the phosphate buffer is less than 1: 2.0, the entrapment rate is reduced, the liposome bilayer structure is changed from ordered arrangement to disordered arrangement, the permeability of the membrane is increased, and the core material leaks; thus, the volume ratio of emulsion to phosphate buffer is 1: preferably 0.5 to 2.0;

the hydration temperature and time exceeding the above range are not preferable because only under such conditions, the gel state substance can be sufficiently hydrated and dropped off to form uniformly distributed liposomes, ensuring a high encapsulation efficiency.

This step is mainly intended for size stabilization, and forms liposome particles of relatively uniform size and small particle size, by filtration through a 0.45 μm filter. The 0.45 μm filter used in the present invention is a commercially available product, for example, a product sold under the trade name of water-based filter 0.45 μm by Seisan Jingbo Biotech Co.

E. And D, pre-freezing the filtrate obtained in the step D at the temperature of minus 80 ℃ for 12 hours, adding 0.08-0.20 part by weight of a freeze-drying protective agent, and carrying out vacuum freeze-drying to obtain the preservative liposome.

The conditions for lyoprotectants have been described above and are therefore not described in detail here.

And D, pre-freezing the filtrate obtained in the step D to ensure that the liposome is in a loose, smooth and full surface state.

In the step, the filtrate added with the freeze-drying protective agent is subjected to vacuum freeze drying for 20-26 h under the conditions that the vacuum degree is 1.3-5.0 Pa and the temperature is-10 to-50 ℃.

When the temperature and the vacuum freeze-drying time are in the range, if the vacuum degree is lower than 1.3Pa, the sublimation water vapor is slow, namely the drying time is prolonged; if the vacuum degree is higher than 5.0Pa, the burden of a vacuum system is increased, and more energy is consumed; therefore, the degree of vacuum is preferably 1.3 to 5.0 Pa;

when the vacuum degree and the vacuum freeze-drying time are in the range, if the temperature is higher than-10 ℃, the product can melt, collapse or shrink; if the temperature is lower than-50 ℃, the burden of a refrigeration system is increased, and more energy is consumed; therefore, a temperature of-10 to-50 ℃ is appropriate;

when the degree of vacuum and the temperature are within the above ranges, the product cannot be completely dried if the vacuum freeze-drying time is shorter than 20 hours; if the vacuum freeze-drying time is longer than 26h, the product can melt, collapse or shrink; therefore, the vacuum freeze drying time is 20-26 h;

the vacuum freeze-drying apparatus used in the present invention is a product currently marketed, for example, by the Beijing Song Huaxing scientific development Co., Ltd under the trade name LGJ-18 freeze-dryer.

It has the following structure, as measured by transmission electron microscopy standard methods: the surface is loose, smooth and full.

Therefore, the preservative liposome prepared by the preparation method is a micro vesicle formed by taking phospholipid and cholesterol as wall materials and encapsulating a preservative, emulsifier and antioxidant mixture core solution.

The preservative liposome encapsulation rate is more than 50 percent by adopting the conventional dialysis method (the literature: Chenjingjing et al, the title: preparation of rice bran polysaccharide iron liposome inclusion compound, food research and development, 2018, v.39; No.341(16): 72-76).

The average particle size of the powder is 350-600 nm measured by a conventional transmission electron microscope.

[ advantageous effects ]

The invention has the following beneficial effects:

1. according to the invention, phospholipid and cholesterol are used as wall materials to form a lipid bilayer membrane, and the preservative is encapsulated to form a micro vesicle, so that the preservative is effectively isolated from being in direct contact with yeast in the baked food, the fermentation influence of the preservative on the yeast is prevented, the preservative effect of the preservative is improved, and the shelf life of the food is prolonged.

2. The preservative liposome prepared by adopting liposome technology is not released at normal temperature, and due to the change of phase transition temperature at high temperature, liposome bilayers are changed from ordered arrangement into disordered arrangement, so that the preservative is slowly released, the concentration of the preservative can be ensured within a certain time range, the high-temperature loss of the preservative is reduced, the effective components of the preservative can be retained in bread to the maximum extent, the purpose of long-term preservation is achieved, and the shelf life of food is prolonged.

3. The particle size of the preservative liposome prepared by the invention can reach the nano level, so that the preservative is more uniformly distributed in the baked food, the preservative effect of the food is improved, and the shelf life of the food is prolonged.

[ description of the drawings ]

FIG. 1: photo picture of baked bread.

In the figure:

a is a photograph of a blank set of baked bread;

b is a photograph of positive control baked bread;

c is a photograph of sample set baked bread.

[ detailed description ] embodiments

The invention will be better understood from the following examples.

Example 1: the preservative liposome of the present invention

The preservative liposome consists of the following components: in parts by weight

The preservative liposome is prepared by adopting the following preparation method:

A. dissolving sorbic acid preservative, 1.0 part by weight of yolk lecithin phospholipid, 0.2 part by weight of cholesterol, 0.06 part by weight of sucrose fatty acid ester emulsifier and 0.014 part by weight of vitamin E antioxidant in 100 parts by weight of a mixture of chloroform and diethyl ether according to the volume ratio of 1: 6 in a mixed solvent;

B. dissolving potassium sorbate preservative in 25 parts by weight of phosphate buffer solution with the pH value of 8.0 and the concentration of 0.02 mol/L; the total amount of sorbic acid and potassium sorbate (weight ratio 2:1) preservative is 0.3 weight part;

C. mixing the solution obtained in step A with the solution obtained in step B, performing ultrasonic treatment for 6min at frequency of 40KHz and power of 250W by using ultrasonic equipment sold under the trade name of KH-250DB type numerical control ultrasonic cleaner by Kunshan Seisakusho ultrasonic instruments ltd to obtain a water-in-oil emulsion, and performing reduced pressure rotary evaporation at temperature of 20 deg.C and rotation speed of 80r/min for 16min to remove solvent;

D. according to the volume ratio of the emulsion to the phosphate buffer solution of 1: 0.5; adding the phosphate buffer solution to the emulsion obtained in step C, mixing well, hydrating at 25 deg.C for 3h, and filtering with 0.45 μm filter membrane sold under the trade name of 0.45 μm water filter by Siemens Crystal Biotech, Inc.;

E. and D, pre-freezing the filtrate obtained in the step D at the temperature of minus 80 ℃ for 12 hours, adding 0.12 part by weight of trehalose freeze-drying protective agent, and carrying out vacuum freeze-drying for 24 hours under the conditions of vacuum degree of 5.0Pa and temperature of minus 36 ℃ to obtain the preservative liposome.

The preservative liposome encapsulation efficiency was 79.2% and its mean particle size was 420nm, as measured by the method described in the specification.

Example 2: the preservative liposome of the present invention

The preservative liposome consists of the following components: in parts by weight

The preservative liposome is prepared by adopting the following preparation method:

A. dissolving a sorbic acid preservative, 0.8 part by weight of soybean lecithin phospholipid, 0.8 part by weight of cholesterol, 0.01 part by weight of sorbitan monooleate emulsifier and 0.001 part by weight of tea polyphenol antioxidant in 50 parts by weight of a mixture of chloroform and diethyl ether according to the volume ratio of 1:1 in a mixed solvent;

B. dissolving sodium propionate preservative in 10 parts by weight of phosphate buffer solution with the pH value of 4.0 and the concentration of 0.01 mol/L; sorbic acid and sodium propionate (1: 1 by weight) preservatives in a total amount of 0.1 parts by weight;

C. mixing the solution obtained in step A with the solution obtained in step B, performing ultrasonic treatment for 4min at frequency of 40KHz and power of 250W by using ultrasonic equipment sold under the trade name of KH-250DB type numerical control ultrasonic cleaner by Kunshan Seisakusho ultrasonic instruments ltd to obtain a water-in-oil emulsion, and performing reduced pressure rotary evaporation for 10min at temperature of 30 ℃ and rotation speed of 60r/min to remove the solvent;

D. according to the volume ratio of the emulsion to the phosphate buffer solution of 1: 1.0; adding the phosphate buffer solution to the emulsion obtained in step C, mixing well, hydrating at 20 deg.C for 2h, and filtering with 0.45 μm filter membrane sold under the trade name of 0.45 μm water filter by Siemens Crystal Biotech, Inc.;

E. and D, pre-freezing the filtrate obtained in the step D at the temperature of minus 80 ℃ for 12 hours, adding 0.08 weight part of beta-cyclodextrin and a freeze-drying protective agent, and carrying out vacuum freeze drying for 20 hours under the conditions that the vacuum degree is 1.3Pa and the temperature is minus 10 ℃ to obtain the preservative liposome.

The encapsulation efficiency of the preservative liposome was 85.3% and its average particle size was 350nm, as measured by the method described in the specification of the present application.

Example 3: the preservative liposome of the present invention

The preservative liposome consists of the following components: in parts by weight

The preservative liposome is prepared by adopting the following preparation method:

A. dissolving sorbic acid preservative, 0.6 part by weight of phosphatidylethanolamine phospholipid, 0.4 part by weight of cholesterol, 0.03 part by weight of monoglyceride laurate emulsifier and 0.008 part by weight of rosemary extract antioxidant in 65 parts by weight of a mixture of chloroform and diethyl ether according to the volume ratio of 1: 4 in a mixed solvent;

B. dissolving calcium propionate preservative in 50 parts by weight of phosphate buffer solution with the pH value of 5.2 and the concentration of 0.03 mol/L; sorbic acid and calcium propionate (weight ratio 2:3) total amount of preservative is 0.8 parts by weight;

C. mixing the solution obtained in step A with the solution obtained in step B, performing ultrasonic treatment for 6min at frequency of 40KHz and power of 250W by using ultrasonic equipment sold under the trade name of KH-250DB type numerical control ultrasonic cleaner by Kunshan Seisakusho ultrasonic instruments ltd to obtain a water-in-oil emulsion, and performing reduced pressure rotary evaporation for 30min at temperature of 40 deg.C and rotation speed of 100r/min to remove solvent;

D. according to the volume ratio of the emulsion to the phosphate buffer solution of 1: 1.5; adding the phosphate buffer solution to the emulsion obtained in step C, mixing well, hydrating at 30 deg.C for 4h, and filtering with 0.45 μm filter membrane sold under the trade name of 0.45 μm water filter by Siemens Crystal Biotech, Inc.;

E. and D, pre-freezing the filtrate obtained in the step D at the temperature of minus 80 ℃ for 12 hours, adding 0.16 part by weight of glucose freeze-drying protective agent, and carrying out vacuum freeze-drying for 22 hours under the conditions of vacuum degree of 5Pa and temperature of minus 24 ℃ to obtain the preservative liposome.

The preservative encapsulation efficiency was 61.7% and its mean particle size was 480nm, as measured by the method described in the specification.

Example 4: the preservative liposome of the present invention

The preservative liposome consists of the following components: in parts by weight

The preservative liposome is prepared by adopting the following preparation method:

A. dissolving sorbic acid preservative, 1.2 parts by weight of distearoyl phosphatidylcholine phospholipid, 0.6 part by weight of cholesterol, 0.05 part by weight of stearoyl calcium lactate emulsifier and 0.020 part by weight of ascorbyl palmitate antioxidant in 84 parts by weight of a mixture of chloroform and diethyl ether according to a volume ratio of 1: 9 in a mixed solvent;

B. dissolving sodium propionate and sodium dehydroacetate preservative in 35 weight portions of phosphate buffer solution with pH value of 6.4 and concentration of 0.04 mol/L; the total amount of sorbic acid, sodium propionate and sodium dehydroacetate (weight ratio 1:1:1) as preservative is 0.5 weight part;

C. mixing the solution obtained in step A with the solution obtained in step B, performing ultrasonic treatment for 8min at frequency of 60KHz and power of 300W by using ultrasonic equipment sold under the trade name of KH-250DB type numerical control ultrasonic cleaner by Kunshan Seisakusho ultrasonic instruments ltd to obtain a water-in-oil emulsion, and performing reduced pressure rotary evaporation for 24min at temperature of 30 deg.C and rotation speed of 80r/min to remove solvent;

D. according to the volume ratio of the emulsion to the phosphate buffer solution of 1: 2.0; adding the phosphate buffer solution to the emulsion obtained in step C, mixing well, hydrating at 25 deg.C for 3h, and filtering with 0.45 μm filter membrane sold under the trade name of 0.45 μm water filter by Siemens Crystal Biotech, Inc.;

E. and D, pre-freezing the filtrate obtained in the step D at the temperature of minus 80 ℃ for 12 hours, adding 0.20 part by weight of mannitol freeze-drying protective agent, and carrying out vacuum freeze-drying for 26 hours under the conditions that the vacuum degree is 4.0Pa and the temperature is minus 50 ℃ to obtain the preservative liposome.

The preservative liposome encapsulation efficiency was 76.5% and its mean particle size was 410nm, as measured by the method described in the specification.

Test example 1: preservative liposome baking experiment

A. Test apparatus

Bread maker using model MM-ESC15101 sold by Tianmao supermarket

B. Bread making

(i) The bread making ingredients are listed in table 1 below.

Table 1: bread making batch

In the table:

blank group is the test group without any added preservative.

The positive control group is a test group added with sorbic acid samples;

the sample group was a test group to which the preservative liposome prepared in example 1 of the present invention was added;

(ii) the specific bread making method is described in the specification of the MM-ESC15101 model American bread maker, and the bread maker program is selected as follows: menu: 01 staple food bread; color: dark color; weight: 500 g.

C. Results of baking experiments

The photo of the baked bread is shown in figure 1.

The baked bread volume was measured as follows:

the bread volume of the blank was 1487.2cm³；

Positive forThe bread volume of the control group was 1385.8cm³；

The bread volume of the sample set was 1487.2cm³。

Fig. 1 and the above measurement results clearly show that the bread size of the sample group is not different from that of the blank group, and the bread size of the positive control group is significantly smaller than that of the blank group and the sample group, which indicates that the preservative liposome prepared in the example can effectively isolate the direct contact between the preservative and the yeast in the baked food and prevent the fermentation influence of the preservative on the yeast.

Test example 2: preservative liposome baking experiment

This experimental example was conducted in the same manner as the experimental example 1 except that the preservative liposomes prepared in examples 2 to 4 were used for parallel experiments.

The test results are as follows:

the photograph of the baked bread is the same as the photograph of fig. 1. The baked bread size measurement results are listed in table 2.

Table 2: examples 2-4 results of the experiment for preparing liposomes as preservatives

The results presented in table 2 clearly show that the bread size of the sample group was not different from that of the blank group, and the bread size of the positive control group was significantly smaller than that of the blank group and the sample group, indicating that the preservative liposome prepared in the examples can effectively isolate the direct contact of the preservative with the yeast in the baked food and prevent the fermentation effect of the preservative on the yeast.