阅读说明：本技术 一种以亚麻木酚素提取物为抗氧化剂的乳液及其制备方法与应用 (Emulsion taking secoisolariciresinol diglucoside extract as antioxidant as well as preparation method and application of emulsion ) 是由 邓乾春 程晨 黄凤洪 禹晓 黄庆德 许继取 于坤 郑畅 于 2020-07-03 设计创作，主要内容包括：本发明公开了一种以亚麻木酚素提取物为抗氧化剂的乳液及其制备方法,属于食品加工技术领域。所述乳液包括油相、水相和乳化剂,所述水相包括亚麻木酚素提取物及所述乳化剂为植物蛋白类乳化剂。本发明公开的乳液体系通过开环异落叶松树脂酚SECO与开环异落叶松树脂酚二葡萄糖苷SDG的比例调控体系的抗氧化性能及稳定性,具有良好的氧化稳定性、较强的热稳定性及较高的脂溶性活性物质的生物可给性。同时本发明还提供了一种在乳化前向水相中添加抗氧化剂的制备方法及所述乳液在保健食品、功能食品以及营养强化食品领域中的应用。(The invention discloses an emulsion taking a secoisolariciresinol diglucoside extract as an antioxidant and a preparation method thereof, belonging to the technical field of food processing. The emulsion comprises an oil phase, a water phase and an emulsifier, wherein the water phase comprises a secoisolariciresinol diglucoside extract, and the emulsifier is a vegetable protein emulsifier. The emulsion system disclosed by the invention regulates the antioxidant property and stability of the system through the proportion of secoisolariciresinol SECO and secoisolariciresinol diglucoside SDG, and has good oxidation stability, strong thermal stability and high biological availability of fat-soluble active substances. Meanwhile, the invention also provides a preparation method for adding an antioxidant into the water phase before emulsification and application of the emulsion in the fields of health-care food, functional food and nutrition-enriched food.)

1. An emulsion taking a secoisolariciresinol diglucoside extract as an antioxidant is characterized by comprising an oil phase, a water phase and an emulsifier, wherein the oil phase is less than or equal to 60 percent, the emulsifier is less than or equal to 10 percent and the rest is the water phase based on the total mass of the emulsion; the oil phase comprises grease, the water phase comprises a secoisolariciresinol diglucoside extract and a phosphate buffer solution, and the emulsifier comprises a vegetable protein emulsifier.

2. The emulsion using secoisolariciresinol diglucoside as an antioxidant according to claim 1, wherein the secoisolariciresinol diglucoside is a mixture of secoisolariciresinol SECO and secoisolariciresinol diglucoside SDG, and the molar ratio of the secoisolariciresinol SECO to the secoisolariciresinol diglucoside SDG is (1:4) - (7: 1).

3. The emulsion of claim 1, wherein the oil comprises one or more of fish oil, DHA algae oil, perilla oil, linseed oil, alpha-linolenic acid, gamma-linolenic acid, docosahexaenoic acid, eicosapentaenoic acid, linoleic acid, and arachidonic acid, and the vegetable protein emulsifier comprises soybean protein, rapeseed protein, sunflower seed protein, and linseed protein.

4. The emulsion using secoisolariciresinol diglucoside as an antioxidant according to claim 1, further comprising a fat-soluble active ingredient, wherein the fat-soluble active ingredient is a carotenoid.

5. The emulsion using the secoisolariciresinol diglucoside extract as the antioxidant according to claim 4, wherein the entrapment rate of the fat-soluble active ingredient is not less than 95%.

6. The emulsion with secoisolariciresinol diglucoside extract as an antioxidant according to claim 1, wherein the emulsion is an oil-in-water emulsion delivery system comprising a nanoemulsion or a regular emulsion.

7. A method for preparing the emulsion with the secoisolariciresinol diglucoside extract as the antioxidant according to claims 1 to 6, which comprises the following steps:

I. adding a vegetable protein emulsifier which accounts for less than or equal to 10 percent of the total mass of the emulsion into the phosphate buffer solution to serve as a water phase for later use;

II. Adding secoisolariciresinol SECO and secoisolariciresinol diglucoside SDG into the water phase obtained in the step I, and stirring overnight at 4 ℃ in a dark place to fully dissolve and uniformly distribute;

and III, adding an oil phase into the mixed solution obtained in the step II, and stirring, shearing and carrying out micro-jet to obtain the emulsion.

8. The method for preparing the emulsion using the secoisolariciresinol diglucoside extract as the antioxidant according to claim 7, wherein the stirring, shearing and microfluidizing conditions in the step III are as follows: the mixed solution was sheared at 10000rpm for 5 minutes, and the microjet pressure was 8000-12000 psi and cycled 4 times.

9. The method of claim 7, wherein the oil phase of step III comprises oils, combinations of carotenoids, or oils.

10. Use of an emulsion according to any one of claims 1 to 6 or an emulsion prepared by a method according to any one of claims 7 to 9 and using a secoisolariciresinol diglucoside extract as an antioxidant in the field of health foods, functional foods and nutrition-enriched foods.

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to an emulsion taking a secoisolariciresinol diglucoside extract as an antioxidant, and a preparation method and application thereof.

Background

The development of the food industry has prompted an ever increasing trend in the demand for fat-soluble active ingredient fortified foods, such as n-3 polyunsaturated fatty acids, fat-soluble vitamins, phytosterols, and the like. But the characteristics of easy oxidation, poor water solubility and the like of fat-soluble bioactive components limit the application of the fat-soluble bioactive components in food. How to introduce active ingredients into food systems becomes a key link in the development of new functional foods. Researchers have developed emulsion-based delivery systems to increase the bioavailability of lipophilic bioactive substances. Oil-in-water emulsions can improve the bioavailability of active substances by modifying their composition and structure. The composition of the oil phase, the composition of the aqueous phase, the droplet size, the type of emulsifier, the physical state of the lipids and the state of droplet aggregation in the emulsion influence the bioavailability of the fat-soluble active substances.

However, many fat-soluble active ingredients are very likely to undergo oxidative rancidity in an emulsion system to cause loss of nutritional functions, and also to generate peroxides and epoxides and the like harmful to the human body, and further to generate unpleasant odors to degrade the product quality, and therefore antioxidants are generally added to the emulsion system.

The natural polyphenol compound serving as a novel antioxidant not only has good oxidation resistance, but also has biological activity which is not possessed by a plurality of artificially synthesized antioxidants. Wherein, the secoisolariciresinol diglucoside is derived from polyphenol compounds with good antioxidant activity in flaxseeds, is also a phytoestrogen, can generate estrogen-like hormone by being metabolized in a human body, and has certain prevention and treatment effects on breast cancer, prostate cancer and the like. The secoisolariciresinol diglucoside has a complex structure, mainly has forms of Secoisolariciresinol (SECO) and diglucoside (SDG), and has different dissolvability and antioxidant activity due to the difference of the structures. However, no study has been reported on the effect of the proportional relationship between Secoisolariciresinol (SECO) and its diglucoside (SDG) on the antioxidant properties of secoisolariciresinol diglucoside.

Therefore, the development of an emulsion using secoisolariciresinol diglucoside as an antioxidant to realize the regulation and control of the antioxidant performance and stability of the system has become a problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the first objective of the present invention is to provide an emulsion using secoisolariciresinol diglucoside as an antioxidant, which has good oxidation stability, strong thermal stability and high bio-availability of fat-soluble active substances by controlling the antioxidant performance and stability of the system according to the ratio of secoisolariciresinol SECO to secoisolariciresinol diglucoside SDG.

In order to achieve the above purpose, the invention provides the following technical scheme:

an emulsion with secoisolariciresinol diglucoside extract as antioxidant comprises oil phase, water phase and emulsifier, wherein the oil phase is less than or equal to 60% and the emulsifier is less than or equal to 10% of the total mass of the emulsion, and the rest is water phase; the oil phase comprises grease, the water phase comprises a secoisolariciresinol diglucoside extract and a phosphate buffer solution, and the emulsifier comprises a vegetable protein emulsifier.

It is worth to say that the vegetable protein is an important protein resource, has high nutritive value and is widely applied in a plurality of fields such as meat products, dairy products and the like. However, the plant protein precipitates around its isoelectric point, and thus cannot function effectively. Therefore, in order to avoid the aggregation caused by the protein denaturation and further flocculation, thereby limiting the practical application of the vegetable protein, the invention limits the weak alkalinity of the emulsion system.

In addition, different from the known emulsifier which only acts on the water-oil separation rate of the system, the plant protein emulsifier adopted by the invention has a certain linkage relationship with the secoisolariciresinol diglucoside extract. Considering the solubility and the variety difference of the protein emulsifiers, the non-covalent interactions (such as hydrogen bonds, hydrophobic interactions, electrostatic interactions and the like) between the protein emulsifiers and the secoisolariciresinol diglucoside are different, so that the distribution of the secoisolariciresinol diglucoside (SECO and SDG) in the water phase can be influenced, and further the antioxidant effect of the secoisolariciresinol diglucoside in an emulsion system is different.

Preferably, the secoisolariciresinol diglucoside is a mixture of secoisolariciresinol SECO and secoisolariciresinol diglucoside SDG, and the molar ratio of the secoisolariciresinol SECO to the secoisolariciresinol diglucoside SDG is (1:4) - (7: 1).

It is worth to be noted that the secoisolariciresinol diglucoside is mainly a polyphenol compound in the seed coat layer of the flaxseed, the Secoisolariciresinol Diglucoside (SDG) exists in the form of macromolecules, the main chain is formed by connecting 3-10 Secoisolariciresinol Diglucoside (SDG) through 3-hydroxy-3-methylglutaric acid (HMGA), and the side chain is formed by phenolic acids such as p-coumaric acid glucoside and ferulic acid glucoside. Therefore, the lignan macromolecules can form secoisolariciresinol diglucoside SDG and aglycone SECO thereof and the like through alkaline hydrolysis and acid hydrolysis. Due to different molecular structures and certain differences of molecular polarities of the lignan macromolecules, the SDG and the SECO, the anti-oxidation action modes of the lignan macromolecules, the SDG and the SECO in different emulsion systems are different. Wherein the low-polarity SECO has better antioxidant activity. Moreover, the SDG and the SECO can generate hydrogen bond interaction with the protein emulsifier to lead the SDG and the SECO to be aggregated at the interface of the emulsion, so that the interface and the antioxidation in the water phase can jointly play the role of antioxidation through free radical removal and metal ion chelation.

In particular, the SECO and SDG with different concentration ratios are used as the antioxidant of the emulsion, so that the controllability of the antioxidant and the selectivity of the emulsifier in an emulsion system can be realized. Particularly, the low water-soluble protein has strong hydrogen bond interaction and hydrophobic interaction with SECO and SDG, so that the antioxidant is more easily present at the interface to play an antioxidant effect; as the solubility of the vegetable protein increases, the hydrophobic interaction between the antioxidant and the emulsifier is weakened, so that the adsorption amount of the antioxidant on the interface is reduced, and the main antioxidant effect of the antioxidant is exerted only by the adsorption of the SECO with weak polarity on the interface.

Preferably, the oil comprises one or more of fish oil, DHA algae oil, perilla oil, linseed oil, alpha-linolenic acid, gamma-linolenic acid, docosahexaenoic acid, eicosapentaenoic acid, linoleic acid and arachidonic acid, and the vegetable protein emulsifier comprises soybean protein, rapeseed protein, sunflower seed protein or linseed protein.

Preferably, the emulsion further comprises a fat-soluble active ingredient, which is a carotenoid.

It is worth mentioning that common carotenoids include lycopene or astaxanthin.

More preferably, the embedding rate of the fat-soluble active ingredients is more than or equal to 95 percent.

Preferably, the emulsion is an oil-in-water emulsion delivery system, including a nanoemulsion or a generic emulsion.

The second purpose of the invention is to provide a preparation method of the emulsion taking the secoisolariciresinol diglucoside extract as the antioxidant.

In order to achieve the above purpose, the invention provides the following technical scheme:

a method for preparing emulsion with secoisolariciresinol diglucoside extract as antioxidant comprises the following steps:

I. adding a vegetable protein emulsifier which accounts for less than or equal to 10 percent of the total mass of the emulsion into the phosphate buffer solution to serve as a water phase for later use;

II. Adding secoisolariciresinol SECO and secoisolariciresinol diglucoside SDG into the water phase obtained in the step I, and stirring overnight at 4 ℃ in a dark place to fully dissolve and uniformly distribute;

and III, adding an oil phase into the mixed solution obtained in the step II, and stirring, shearing and carrying out micro-jet to obtain the emulsion.

It is worth noting that SDG and SECO in the secoisolariciresinol diglucoside extract can improve the chemical stability of the emulsion system through a synergistic effect. In general, for highly water-soluble proteins, the higher the proportion of SECO, the better the antioxidant effect; for moderately water-soluble proteins, SECO: when the ratio of SDG is higher than or equal to 4:1, the synergistic antioxidant effect is better; for low water soluble proteins (solubility > 50%), SECO: when the SDG ratio is higher than or equal to 3:1, the synergistic antioxidant effect is better.

Particularly, the antioxidant is innovatively added into the water phase before emulsification, and researches show that the antioxidant concentration in the water phase can also participate in the antioxidant process of the oil core, and the antioxidant efficiency is synergistically improved by the interfacial antioxidant.

In addition, considering the problems of the isoelectric point of the vegetable proteins, the electrostatic interaction condition of the secoisolariciresinol diglucoside and the vegetable protein emulsifier and the like, the pH range of the adopted phosphate buffer solution is 7-9. Within the pH range, the vegetable protein has better solubility, and can promote the intermolecular interaction of the hydroxyl of the secoisolariciresinol diglucoside and the protein, thereby being beneficial to positioning the secoisolariciresinol diglucoside on the interface of the emulsion.

Preferably, the stirring, shearing and micro-jet conditions in step III are as follows: the mixed solution was sheared at 10000rpm for 5 minutes, and the microjet pressure was 8000-12000 psi and cycled 4 times.

Preferably, the oil phase in step III comprises an oil, a combination of carotenoids or an oil.

The third purpose of the invention is to provide the application of the emulsion taking the secoisolariciresinol diglucoside extract as the antioxidant.

In order to achieve the above purpose, the invention provides the following technical scheme:

an emulsion containing secoisolariciresinol diglucoside extract as antioxidant is used in health food, functional food and nutrition-enriched food.

It is worth noting that emulsions with secoisolariciresinol diglucoside as an antioxidant reduce the amount of exposed hydroxyl groups of SECO or SDG by cross-linking with proteins, thus reducing the astringency they impart and improving the mouthfeel of oral delivery systems. And the generation and volatilization of small molecular flavor substances with special fishy smell generated by the oxidation of the oil and fat of the polyunsaturated oil such as fish oil, DHA algae oil and linseed oil are reduced through the antioxidation and the encapsulation of the protein emulsifier on the oil and fat.

Compared with the prior art, the invention has the advantages that:

1. the invention applies the blending type homologous antioxidant to an emulsion system for the first time, the emulsion using the secoisolariciresinol diglucoside extract as the antioxidant has good oxidation stability and stronger thermal stability, after being stored at the room temperature of 37 ℃ for 1 month, the content of hydroperoxide is less than or equal to 10mmol/kgoil, the particle size change is less than 10 percent, and the physical unsteady phenomena of oil-water, elutriation, delamination, gravity settling and the like do not occur;

2. the invention firstly uses vegetable proteins with different solubilities as emulsifiers, controls the oxidation of grease by adjusting the proportion of SECO and SDG, and finds out the linkage relation between the secoisolariciresinol diglucoside proportion and the oxidation of an emulsion system prepared by using oil-source vegetable proteins as emulsifiers.

3. The oil phase in the emulsion system with the secoisolariciresinol diglucoside extract as the antioxidant can be used for loading fat-soluble bioactive components such as lycopene, astaxanthin and the like, the embedding rates of the oil phase and the oil phase are all higher than 95%, the oil phase and the oil phase are stable to oxidation, and the retention rates of the components such as lycopene, astaxanthin and the like are all higher than 90% when the emulsion system is stored at room temperature of 37 ℃ for 1 month. Through in vitro simulation, the release rate of free fatty acid of the digested oil reaches up to 90 percent, and the bioavailability of bioactive components such as astaxanthin, lycopene and the like can be obviously improved.

4. The invention takes SECO to SDG with different concentration ratios as the antioxidant of the emulsion, the method has the advantages that the controllability of the antioxidant and the selectivity of the emulsifier are good, and the hydrogen bond interaction and the hydrophobic interaction of the low water-soluble protein, SECO and SDG are strong, so that the antioxidant is easier to exist in the interface to play the antioxidant effect; however, as the solubility of the vegetable protein increases, the hydrophobic interaction between the antioxidant and the emulsifier decreases, so that the amount of the antioxidant adsorbed at the interface decreases, and the primary antioxidant effect is exerted only by the adsorption of the less polar SECO at the interface.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.