阅读说明：本技术 一种以茶多酚为络合物制备有机凝胶提高精炼植物油抗氧化性能的方法 (Method for preparing organogel by taking tea polyphenol as complex to improve oxidation resistance of refined vegetable oil ) 是由 潘风光 李园园 罗翔丹 隋晓琳 于 2020-04-06 设计创作，主要内容包括：本发明公开了一种以茶多酚为络合物制备有机凝胶提高精炼植物油抗氧化性能的方法,该方法包括先将天然抗氧化剂茶多酚粉末溶于水中作为水相,将含有蔗糖的硬脂酸作为有机凝胶剂进行水浴得到均匀的澄清溶液。然后将水相和油相进行均质得到稳定的乳状液,最后将乳状液在液氮中快速冷冻后进行冻干得到茶多酚有机凝胶复合物。最后将其以一定的比例添加至精炼后的植物油脂中进行混合,以提高植物油脂的抗氧化性能。对提高精炼后植物油的坑氧化能力,改善油脂品质,延长油脂的货架期有着较大的实际意义。(The invention discloses a method for preparing organic gel by taking tea polyphenol as a complex to improve the oxidation resistance of refined vegetable oil. And homogenizing the water phase and the oil phase to obtain stable emulsion, and finally, quickly freezing the emulsion in liquid nitrogen and freeze-drying to obtain the tea polyphenol organogel compound. And finally, adding the mixture into refined vegetable oil according to a certain proportion for mixing so as to improve the oxidation resistance of the vegetable oil. Has great practical significance for improving the pit oxidation capacity of the refined vegetable oil, improving the quality of the oil and prolonging the shelf life of the oil.)

1. A method for preparing organogel by taking tea polyphenol as a complex to improve the oxidation resistance of refined vegetable oil comprises the following steps: firstly, dissolving natural antioxidant tea polyphenol powder in water to be used as a water phase, and carrying out water bath on stearic acid containing cane sugar to be used as an organic gel to obtain a uniform clear solution; homogenizing the water phase and the oil phase to obtain stable emulsion, and freeze-drying the emulsion after rapidly freezing in liquid nitrogen to obtain tea polyphenol organogel compound; and finally, adding the mixture into refined vegetable oil and fat for mixing so as to improve the oxidation resistance of the oil and fat.

2. The method of claim 1, wherein the tea polyphenols is food grade tea polyphenols powder and the stearic acid is sucrose (5% w/w) stearic acid.

3. The method for preparing organogel with tea polyphenol as complex to improve the antioxidant properties of refined vegetable oil as claimed in claim 2, wherein stearic acid containing sucrose (5% w/w) is placed in a water bath at 80 ℃ to perform the water bath until a homogeneous clear solution is obtained; when the tea polyphenol is added into stearic acid, and the adding concentration is 1-5% (w/w), stable and uniform emulsion can be obtained.

4. The method for preparing organogel with tea polyphenol as complex to improve the antioxidant property of refined vegetable oil as claimed in claim 3, wherein said method comprises the steps of:

(1) dissolving 100mg of natural antioxidant tea polyphenol powder in 2m L water as water phase, placing 10g of stearic acid containing sucrose (5% w/w) in 80 deg.C water bath, and stirring at 500rmp speed until uniform clear solution is obtained;

(2) adding the tea polyphenol water phase obtained in the step (1) into stearic acid, dissolving to obtain a solution with a concentration of 1%, homogenizing the mixed solution at 26000rpm for 2min to form a stable uniform emulsion; the homogenization temperature is 80 ℃;

(3) rapidly freezing the emulsion obtained in the step (2) in liquid nitrogen, and then freeze-drying to obtain a tea polyphenol organogel compound;

(4) mixing the organogel compound obtained in the step (3) with vegetable oil according to the proportion of 1:20, and sufficiently and uniformly mixing the tea polyphenol organogel compound with the vegetable oil by using a vortex oscillator so as to improve the antioxidant capacity of the refined vegetable oil; taking the vegetable oil without the tea polyphenol organogel compound as a blank control;

(5) the mixed grease and blank sample are subjected to certain accelerated oxidation, and the change of the anti-oxidation capability of the grease is detected by measuring the peroxide value (POV).

Technical Field

The invention relates to a method for improving the oxidation resistance of refined vegetable oil, in particular to a method for improving the oxidation resistance of refined vegetable oil by using natural antioxidant tea polyphenol.

Background

Vegetable oils are rich in unsaturated fatty acids, such as common soybean oil, peanut oil, olive oil, linseed oil, and the like. Unsaturated fatty acid is a fatty acid that constitutes body fat and is essential to the human body. The unsaturated fatty acid in vegetable oil has effects of reducing blood cholesterol and triglyceride, reducing blood viscosity, improving blood microcirculation, increasing brain cell activity, and enhancing memory and thinking ability. However, polyunsaturated fatty acids are extremely susceptible to oxidation because they contain multiple double bonds. The oxidized unsaturated fatty acid can generate unpleasant smells such as fishy smell and rancidity, and the quality guarantee period of the vegetable oil and fat can be seriously influenced. And when the plant oil containing the oxidative free radicals is taken by a human body, certain harm is brought to the health of the human body.

Vegetable oil, after being initially pressed, contains undesirable impurities such as phospholipids, pigments, free fatty acids and the like, thereby affecting the taste, color and flavor thereof, so that the vegetable oil needs to be refined. At present, vegetable oil eaten by people is refined to a certain extent, and the main physical and chemical properties of the vegetable oil can be changed to a certain extent through a refining process, so that the obtained finished oil meets the national standards of indexes such as the acid value, the peroxide value and the like of edible vegetable oil, but nutrient substances in the vegetable oil, such as tocopherol, total phenol, squalene and the like, are lost to a certain extent due to the fact that the oil is subjected to high temperature and the like in the refining process, the antioxidant property of the vegetable oil is reduced, and the nutrient quality of the vegetable oil is influenced to a certain extent.

With the continuous improvement of living standard of people, the consumption of edible vegetable oil is increasing year by year, people pay more attention to the nutrition and quality of the oil, and the oxidation resistance of the refined vegetable oil has great influence on the quality of the vegetable oil in the subsequent packaging, storage, transportation and other processes. At present, the main method for reducing the oxidative deterioration of edible oil is to apply an antioxidant. Antioxidants terminate lipid peroxidation chain reactions by scavenging free radical intermediates and inhibiting other oxidative reactions. At present, there are hundreds of chemical synthetic antioxidants commonly used internationally for oil and fat oxidation resistance, for example, tert-butylhydroquinone (TBH Q), dibutylhydroxytoluene (BH T), butylhydroxyanisole (BH a), Propyl Gallate (PG), and the like are commonly used in edible vegetable oils. However, the safety of chemically synthesized antioxidants has long been questioned. Some experimental studies have shown that BHT and BHA are carcinogenic to animals, and TBHQ also has the potential to be carcinogenic in certain circumstances. In order to avoid the harm of chemical antioxidants to human health, natural antioxidants can be added into the vegetable oil according to the nature of the natural antioxidants.

Natural antioxidants are widely found in nature and are of a wide variety. Wherein the tea polyphenol is used as a natural antioxidant, and has the effects of extremely strong removal of harmful free radicals, blockage of lipid peroxidation process and improvement of the activity of enzymes in a human body, thereby having the effects of mutation resistance and cancer resistance. Researches show that the edible oil added with tea polyphenol can prevent and delay the automatic oxidative decomposition of unsaturated fatty acid, thereby preventing the quality of the oil from being deteriorated and prolonging the storage period of the oil by more than one time. But because of strong hydrophilicity, the solubility and the interfacial dispersion performance are not very good when the antioxidant is directly added into vegetable oil, thereby greatly inhibiting the application of the antioxidant in grease.

Aiming at the defects that the oxidation resistance of the vegetable oil is reduced after the vegetable oil is refined, the unsaturated fatty acid in the vegetable oil is easy to oxidize and rancid, the oxidation resistance of tea polyphenol cannot be well exerted in the vegetable oil due to the characteristic of water solubility, and the like, the invention provides a method for improving the oxidation resistance of the refined grease by adding the organogel prepared by taking the tea polyphenol as a complex into the refined vegetable oil, so that the grease quality is improved, and the shelf life of the grease is prolonged.

Disclosure of Invention

The invention aims to provide a method for improving the oxidizing property of refined vegetable oil by using natural antioxidant tea polyphenol as a complex to prepare organic gel aiming at the defects that the prior oil is seriously oxidized and deteriorated after being refined and the effect of the prior antioxidant is not ideal.

The purpose of the invention is realized by the following technical scheme:

a method for preparing organogel by taking tea polyphenol as a complex to improve the oxidation resistance of refined vegetable oil comprises the following steps: firstly, dissolving natural antioxidant tea polyphenol powder in water to be used as a water phase, and carrying out water bath by taking stearic acid containing cane sugar as an organic gel to obtain a uniform clear solution. And homogenizing the water phase and the oil phase to obtain stable emulsion, and finally, quickly freezing the emulsion in liquid nitrogen and freeze-drying to obtain the tea polyphenol organogel compound. And finally, adding the mixture into refined vegetable oil and fat for mixing so as to improve the oxidation resistance of the oil and fat.

Preferably, the tea polyphenol is food grade tea polyphenol powder, and the stearic acid is stearic acid containing sucrose (5% w/w).

Preferably, stearic acid containing sucrose (5% w/w) is placed in a water bath at 80 ℃ in a water bath until a homogeneous clear solution is obtained.

Preferably, when tea polyphenol is added to stearic acid at a concentration of 1% to 5% (w/w), a stable homogeneous emulsion can be obtained.

Preferably, the aqueous phase and the oil phase are homogenized at 80 ℃ to ensure that the oil phase is always in a liquid state during homogenization.

The method comprises the following steps as a preferable scheme:

(1) dissolving 80-120 mg of natural antioxidant tea polyphenol powder in 1-3 m L of water to be used as a water phase, putting 5-15 g of stearic acid containing sucrose (5% w/w) in a water bath at 80 ℃ for water bath, and stirring at the speed of 500rmp until a uniform clear solution is obtained.

(2) Adding the tea polyphenol water phase obtained in the step (1) into stearic acid, dissolving, and then homogenizing the mixed solution at 26000rpm for 2min to form stable and uniform emulsion, wherein the concentration of the dissolved tea polyphenol water phase is 1-5%. The homogenization temperature was 80 ℃.

(3) And (3) quickly freezing the emulsion obtained in the step (2) in liquid nitrogen, and then freeze-drying to obtain the tea polyphenol organogel compound.

(4) And (3) mixing the organogel compound obtained in the step (3) with vegetable oil according to a certain ratio (1-4: 20), and fully and uniformly mixing the tea polyphenol organogel compound and the vegetable oil by using a vortex mixer so as to improve the antioxidant capacity of the refined vegetable oil.

Further, the method comprises the steps of:

(1) 100mg of the natural antioxidant tea polyphenol powder was dissolved in 2m L water as the aqueous phase, 10g of stearic acid containing sucrose (5% w/w) was placed in a water bath at 80 ℃ and subjected to a water bath with stirring at 500rmp until a homogeneous clear solution was obtained.

(2) Adding the tea polyphenol water phase obtained in the step (1) into stearic acid, dissolving to obtain a solution with a concentration of 1%, homogenizing the mixed solution at 26000rpm for 2min to form a stable uniform emulsion. The homogenization temperature was 80 ℃.

(3) And (3) quickly freezing the emulsion obtained in the step (2) in liquid nitrogen, and then freeze-drying to obtain the tea polyphenol organogel compound.

(4) Mixing the organogel compound obtained in the step (3) with the vegetable oil according to the proportion of (1:20), and fully and uniformly mixing the tea polyphenol organogel compound and the vegetable oil by using a vortex oscillator so as to improve the antioxidant capacity of the refined vegetable oil. The vegetable oil without tea polyphenol organogel complex added was used as a blank control.

(5) The mixed grease and blank sample are subjected to certain accelerated oxidation, and the change of the anti-oxidation capability of the grease is detected by measuring the peroxide value (POV).

The invention has the beneficial effects that:

1. the invention adopts the natural antioxidant tea polyphenol with stronger inoxidizability to improve the inoxidizability of the refined grease, solves the safety problem of the artificial synthetic antioxidant used in the industry at present, improves the nutrition and the quality of the edible grease, and has certain health care effects of anti-inflammation, cancer prevention, anti-aging and the like.

2. According to the invention, the tea polyphenol is combined with stearic acid as a complex to prepare an organogel compound which can be mutually dissolved with vegetable oil, so that the oxidation resistance of refined oil is improved, the tea polyphenol can be uniformly distributed in the oil, the oxidation resistance effect is improved, and the problems of complex operation technology, influence of solvent residue on the oil quality and the like in the prior art are solved.

3. The invention effectively improves the oxidation resistance of the refined grease in the subsequent processing, storage and transportation processes, and avoids the grease from further generating unpleasant odor such as putrefaction, rancidity and the like by effectively reducing the generation of hydroperoxide, thereby enhancing the stability of the grease and prolonging the shelf life. Plays a certain promoting role in improving the healthy diet quality of people.

Detailed Description

In order that the invention may be better understood, the invention will now be further described with reference to the following examples.