An antioxidant suitable for high-temperature oil oxidation and a preparation method thereof

Abstract

The application provides an antioxidant for high-temperature oil and fat and a preparation method thereof, and comprises the following raw materials in parts by weight: 5-15 parts of fat-soluble rosemary extract, 5-15 parts of water-soluble rosemary extract, 5-10 parts of water-dispersible rosemary oil, 5-15 parts of an emulsifier, 30-50 parts of an oil mixture, 15-25 parts of a solvent and 0.5-5 parts of a chelating agent; the emulsifier comprises at least one of glycerol, phospholipids and derivatives, mono-diglyceride fatty acid ester, citric acid fatty acid glyceride, propylene glycol fatty acid ester and diacetyl tartaric acid mono-diglyceride. The components and the ratio are scientifically selected, and the multiple emulsion antioxidant is prepared in steps, so that the oxidation rate of the oil and fat, such as frying oil, or oil-rich food during high-temperature treatment for a long time can be delayed, the oxidation induction time of the oil and fat can be prolonged, and the generation of carbonyl compounds in the high-temperature oil and fat can be inhibited. The comprehensive protection effect of the antioxidant is not lower than that of TBHQ in the field of high-temperature oil and fat at 165 DEG C and above.

Description

Technical Field

[0001] This invention relates to the field of food additives technology, and in particular to an antioxidant suitable for high-temperature oil oxidation and its preparation method. Background Technology

[0002] In daily life, most of the oils and fats we consume, or foods containing a high amount of oil, undergo oxidation reactions in the air. This is especially true for oils that have been heated at high temperatures, particularly those that have been fried for extended periods. These oils will darken in color, thicken in viscosity, and experience a decline in taste and flavor. The heat processing process also produces harmful components such as thermal hydrolysis products (free fatty acids, monoglycerides, and diglycerides), thermal oxidative degradation products (hydroperoxides, aldehydes, ketones, acids, and alcohols), thermal isomerization products (trans fatty acids), and thermal polymerization products (epoxides and polymers).

[0003] The formation and accumulation of these harmful components in food typically manifest as increased levels of lipid peroxide value, carbonyl value, and acid value, while decreasing levels of iodine value, altered food color, and the production of unpleasant odors such as rancidity. These harmful substances not only lead to substandard food quality but, more importantly, pose serious health risks. For example, the free radicals they produce can accelerate cell aging; aldehydes, ketones, secondary oxidation products, polymers, and polycyclic aromatic hydrocarbons have potential carcinogenicity; and trans fatty acids can accelerate arteriosclerosis and induce cardiovascular and cerebrovascular diseases, cognitive decline, diabetes, breast cancer, and many other harmful effects.

[0004] To slow down the oxidation of fats and oils in food, antioxidants are usually added. Currently, the most widely used synthetic antioxidants in oils and oils include BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene), and TBHQ (tert-butylhydroquinone). Synthetic antioxidants are widely used due to their good antioxidant effects, low cost, and solubility in oils and oils. However, due to potential safety risks, their use is being banned in an increasing number of countries. BHA is listed as a Group 2B carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization, and BHT and TBHQ are already banned in Japan. With increasing health awareness, the use of synthetic antioxidants will face even more restrictions.

[0005] Therefore, natural antioxidants are now favored by more industries. Among traditional natural antioxidants, water-soluble antioxidants, mainly vitamin C and tea polyphenols, have good antioxidant effects in water-soluble environments and are widely used. However, they have poor solubility and thermal stability at high temperatures, especially in high-temperature oils. Fat-soluble antioxidants, mainly vitamin E, also suffer from poor thermal stability and low antioxidant effects at high temperatures in oils. As for some antioxidant components, such as phenolic acids and flavonoids, which are mainly extracted, most are still in the research stage. Although many types of components have shown good high-temperature thermal stability and antioxidant effects, there are some problems in industrial production, commercial application, and regulatory compliance, making it difficult to promote and apply them in a short period of time.

[0006] Natural antioxidants are typically used directly or dissolved with the aid of alcohols or oils, or prepared as water-in-oil emulsions, or in combination with fat-soluble antioxidants. The most severe oxidation of high-temperature oils, especially frying oils, occurs at the oil-air and oil-water interfaces. The first two methods suffer from problems such as low antioxidant concentration due to oil dispersion, relatively poor antioxidant effect at the most oxidized interfaces, and the evaporation of alcohol solvents causing antioxidant precipitation, reducing the antioxidant concentration in the oil and affecting sustained antioxidant effects. While water-in-oil antioxidants, polar antioxidants, and those used in combination with fat-soluble antioxidants offer good stability and good antioxidant performance at the oil-air and oil-water interfaces, the low concentration of fat-soluble antioxidants inside the food and the difficulty in maintaining a uniform concentration of polar antioxidants can lead to inconsistent quality and unstable shelf life in fried foods.

[0007] Rosemary is a commonly used spice in everyday cooking, widely applied in many countries. Rosemary essential oil is obtained through steam distillation, while rosemary extract is obtained through solvent extraction. The antioxidant components in dried rosemary leaves are separated, enriched, and purified to obtain rosemary extract, a process with mature industrial production and commercial application. The main components of rosemary essential oil are α-pinene, verbenatone, and 1,8-cineole, among others. As a food flavoring, it possesses a unique aroma and also exhibits certain antioxidant and antibacterial properties. Rosemary extract primarily consists of diterpenoid phenols and organic acids, with the main active ingredients being carnosic acid, rosmarinic acid, and carnosol. Carnosic acid and carnosol are fat-soluble, while rosmarinic acid is water-soluble. Rosemary extract exhibits good safety and thermal stability, is heat-resistant, and does not readily volatilize. Its antioxidant effect in high-temperature oils is also quite significant, leading to its wide range of applications in food, particularly abroad where it is widely used as a seasoning. Its safety risks in food applications are low, and it enjoys good compliance. Therefore, it is suitable for use as a substitute for synthetic antioxidants such as TBHQ in high-temperature oils.

[0008] Chinese patent CN103767042A discloses a natural antioxidant and its preparation method, using a compound of natural substances and tea polyphenols, and employing a solvent for solubilization. However, the solvent in this method has low solubility in oils and fats, which cannot guarantee the dispersibility and stability of the antioxidant in oils and fats. Chinese patent CN112841257A discloses a compound antioxidant and its preparation method for improving the stability of frying oils and fried foods, using multiple antioxidants such as rosemary extract, tea polyphenols, vine tea extract, ascorbyl palmitate, and vitamin C. However, tea polyphenols are prone to browning at high temperatures, vine tea extract has not yet been approved under Regulation 2760, ascorbyl palmitate is a synthetic antioxidant, not a purely natural one, and vitamin C requires encapsulated vitamin C products. Vitamin C has poor thermal stability under long-term processing, and the wall material has certain issues regarding safety and compliance. Furthermore, it discloses ethanol as a solvent; according to relevant literature, oxalic acid in rosemary extract slowly degrades into other components in ethanol. When ethanol is used as a cosolvent, the main active ingredient in rosemary extract, caryopsisic acid, will be lost to some extent during storage, potentially reducing its antioxidant effect. Therefore, products using this technology may encounter stability, safety, and compliance issues when used in high-temperature oils. Summary of the Invention

[0009] Therefore, the purpose of this invention is to provide an antioxidant suitable for high-temperature oil oxidation and its preparation method. The main active ingredients are fat-soluble rosemary extract, water-soluble rosemary extract, and rosemary oil, all derived from the rosemary plant, making them natural, safe, and healthy. The solvents used can be evaporated during high-temperature processing or are naturally occurring components in the food itself. After the solvent evaporates, the water-soluble rosemary extract can still form micelles with the phospholipids in the oil mixture and remain stably dispersed in the oil, exhibiting good safety and high-temperature stability. The emulsifier has few restrictions on use, requires a low dosage, and is not easily decomposed by heat. The chelating agent can chelate metal ions, reducing the catalytic oxidation of high-temperature oils by metal ions. Simultaneously, the chelating agent, along with phospholipids and their derivatives, not only chelates and emulsifies but also donates hydrogen to the antioxidant, prolonging its action time. Therefore, this technology and product better meet practical needs in terms of high-temperature thermal stability, food safety, compliance, and industrial application. Meanwhile, by employing a multiple emulsion preparation method, an antioxidant suitable for high-temperature oil oxidation can be prepared. This method can slow down the release rate of active ingredients, increase the concentration of active ingredients at the oil-air and oil-water interfaces, and prolong the action time of active ingredients, achieving controlled and delayed release. This technology not only produces rosemary oil with a low odor and provides good aroma enhancement during use, but also, through the controlled release of fat-soluble rosemary extract and the synergistic effect of water-soluble rosemary extract, provides a comprehensive protective effect no less than TBHQ, delaying oil oxidation and effectively extending the service life of high-temperature oils and the shelf life of foods subjected to high-temperature frying and baking.

[0010] The technical solution of this invention is implemented as follows:

[0011] An antioxidant suitable for high-temperature oil oxidation resistance, comprising the following raw materials in parts by weight: 5-15 parts of fat-soluble rosemary extract, 5-15 parts of water-soluble rosemary extract, 5-10 parts of water-dispersible rosemary oil, 5-15 parts of emulsifier, 30-50 parts of oil mixture, 15-25 parts of solvent and 0.5-5 parts of chelating agent;

[0012] The emulsifier includes at least one of glycerol, phospholipids and their derivatives, mono- and diglycerides of fatty acids, glycerides of citric acid fatty acids, propylene glycol fatty acids, and diacetyl tartaric acid mono- and diglycerides; phospholipids and their derivatives include phospholipids and / or enzymatically hydrolyzed soybean phospholipids and / or modified soybean phospholipids, etc.

[0013] The oil mixture is composed of oils and phospholipids. The listed oils are vegetable oils such as sunflower oil and palm oil, which are commonly used in the production of high-temperature food products. They may also be other vegetable oils such as rapeseed oil or animal fats, or edible oils such as medium-chain triglycerides or mixtures thereof.

[0014] The water-dispersible rosemary oil is composed of rosemary oil as the main component, fat-soluble rosemary extract, and emulsifier.

[0015] A further embodiment comprises the following raw materials in parts by weight: 9-10 parts of fat-soluble rosemary extract, 12-15 parts of water-soluble rosemary extract, 6-8 parts of water-dispersible rosemary oil, 7-11 parts of emulsifier, 30-40 parts of oil mixture, 20-25 parts of solvent, and 2-4 parts of chelating agent. A further embodiment further comprises the emulsifier being a phospholipid and its derivatives, mono- and diglycerides of fatty acids, and propylene glycol fatty acid esters in a mass ratio of 0.5-4:0.5-4:0.5-1.5; or the emulsifier being a phospholipid and its derivatives, mono- and diglycerides of fatty acids, and citrate fatty acid glycerides in a mass ratio of 0.5-4:0.5-4:0.5-1.5.

[0016] The solvent is at least one of water, propylene glycol, glycerol, acetic acid, phytic acid, and ethyl acetate; the listed solvents are edible hydrophilic liquid solvents or mixtures thereof with a certain solubility in water and containing hydroxyl, carboxyl, or ester groups. They can be water, edible liquid alcohol solvents such as propylene glycol and glycerol, or other edible hydrophilic liquid solvents such as acetic acid and phytic acid, or edible ester solvents such as ethyl acetate with a certain solubility in water. Preferably, it is water or glycerol and a certain proportion of their mixture.

[0017] The chelating agent is citric acid and / or phytic acid.

[0018] A further embodiment is that the oil mixture consists of phospholipids and rapeseed oil in a mass ratio of 0.5–2:0.5–2.

[0019] The present invention also provides a method for preparing an antioxidant suitable for high-temperature oil anti-oxidation, comprising: step S1, dissolving water-soluble rosemary extract into solution A by means of solvent, chelating agent and partial emulsifier;

[0020] Step S2: Water-dispersible rosemary oil is added to solution A and stirred to emulsify and dissolve, resulting in an O / W type emulsion B;

[0021] Step S3: Dissolve the fat-soluble rosemary extract into solution C using an oil mixture and the remaining emulsifier;

[0022] Step S4: By mixing and emulsifying O / W type emulsion B and solution C, a multi-emulsion type antioxidant is obtained.

[0023] A further option is that, in step S1, the emulsifier is enzymatically hydrolyzed soybean lecithin and / or modified soybean lecithin; in step S3, the emulsifier is mono- and diglyceride fatty acid esters and propylene glycol fatty acid esters, or the emulsifier is mono- and diglyceride fatty acid esters and citrate fatty acid glycerides.

[0024] A further option is that the main active ingredients of the water-dispersible rosemary oil added in step S2 are rosemary oil and fat-soluble rosemary extract, wherein the rosemary oil also acts as a solvent to dissolve and disperse the fat-soluble rosemary extract.

[0025] A further embodiment is that the mass ratio of the fat-soluble rosemary extract in the water-dispersible rosemary oil added in step S2 to the fat-soluble rosemary extract added in step S3 is 0.1-1:1-2.

[0026] A further approach is to mix the solvent, chelating agent, partial emulsifier, and water-soluble rosemary extract in step S1, stir, and heat to 60-85°C.

[0027] A further step is as follows: In step S2, when the temperature of solution A is 60-70℃, water-dispersible rosemary oil is slowly added to solution A, and stirring is continued at 3000-8000 r / min for 15-30 min; In step S3, the oil mixture is taken, fat-soluble rosemary extract and the remaining emulsifier are added, stirred, and heated to 60-85℃; In step S4, when the temperature of O / W emulsion B and solution C drops below 55℃, O / W emulsion B is slowly added to solution C, and stirring is continued at 600-2000 r / min for 5-20 min.

[0028] During high-temperature frying, vigorous oxidation and hydrolysis reactions occur at the oil-water interface and within the fried product, while the oxidation rate of other oils is relatively slow. Adding a multi-emulsion type rosemary antioxidant allows its active ingredients to be slowly released within the oil after dispersion. The outermost layer of fat-soluble rosemary extract is released most quickly, protecting the oil surrounding the entire frying system. After the outer layer of antioxidants is released, the middle layer, including water-soluble rosemary extract and chelating agents, is hydrophilic and tends to accumulate more at the oil-water interface and penetrate the fried product. The chelating agents remove metal ions that catalyze oxidation and also donate hydrogen to the rosemary antioxidants, prolonging the antioxidant effect and duration. When the solvent dissolving the water-soluble rosemary extract and chelating agents evaporates, the phospholipids in the oil mixture form micelles that protect and disperse the water-soluble components for a certain period, preventing the leaching of water-soluble components after solvent evaporation from affecting the overall antioxidant effect. The innermost layer of rosemary oil and fat-soluble rosemary extract are also carried into the interior of the fried product, where they are released in greater quantities. Rosemary oil not only enhances the aroma, giving the product a long-lasting and unique fragrance, but also acts as a solvent during preparation, dissolving the fat-soluble rosemary extract. It also synergistically enhances the antioxidant effect with the fat-soluble rosemary extract. Simultaneously, the innermost layer of antioxidants can penetrate the food, leaving some antioxidants with the oil, thus slowing down the oxidation rate of the frying oil and its oils after prolonged high-temperature processing, effectively extending the shelf life of the frying oil.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] This invention utilizes a mixture of fat-soluble rosemary extract, water-soluble rosemary extract, water-dispersible rosemary oil, emulsifiers (glycerol, phospholipids and derivatives, mono- and diglyceride fatty acid esters, propylene glycol fatty acid esters, etc.), and an aqueous solution of glycerol as a solvent. Through scientific formulation and step-by-step preparation, a multi-emulsion type antioxidant is obtained, providing an antioxidant for use in oils at high temperatures. This formulation exhibits good safety. In a comparative test of antioxidant properties with TBHQ in high-temperature frying oils, this antioxidant significantly outperformed TBHQ in iodine value, carbonyl value, and color comparison. In the oil oxidation stability test, the oil oxidation induction time was better than or only slightly lower than TBHQ. In the oil oven acceleration test, the initial peroxide value was lower than TBHQ, while the total acceleration time was comparable to TBHQ.

[0031] This invention defines a product formulation and preparation method for a rosemary antioxidant for use in oils at high temperatures. The product prepared using this method is free-flowing, has good stability, and is easy to disperse and stable in oils and at high temperatures, making it suitable for industrial production and end-user applications.

[0032] By using fat-soluble rosemary extract, water-soluble rosemary extract, water-dispersible rosemary oil, emulsifiers (glycerol, phospholipids and derivatives, mono- and diglyceride fatty acid esters, propylene glycol fatty acid esters, etc.), oil mixtures, and glycerol aqueous solution as solvents, a multi-emulsion type antioxidant was obtained. This antioxidant not only slows down the oxidation rate of oils, but also gives the frying oil products treated with this antioxidant a special flavor and excellent sensory evaluation. Attached Figure Description

[0033] Figure 1 The graph shows the change in oxidation induction time of the oil in each group of French fries after high-temperature treatment at 185-190 degrees Celsius as a function of treatment time.

[0034] Figure 2 The graph shows the change in carbonyl value of the oil in each group of French fries after high-temperature treatment at 185-190 degrees Celsius with treatment time.

[0035] Among them, Group A was the blank control group, Group B was the TBHQ sample group (TBHQ added to the oil at a rate of 0.2‰), Group C was the sample group of Example 1 (TBHQ added to the oil at a rate of 0.7‰), and Group D was the sample group of Comparative Example 1, which used ethanol as the solvent and had the same composition of fat-soluble rosemary extract and water-dispersible rosemary oil as Group C. The water-soluble rosemary extract was replaced with an equal amount of tea polyphenols (0.7‰ added to the oil).

[0036] Figure 3 The graph shows the change in oxidation induction time of walnut oil in each group after high-temperature treatment at 200-205 degrees Celsius as a function of treatment time.

[0037] Figure 4 The graph shows the change in iodine value of walnut oil in each group after high-temperature treatment at 200-205 degrees Celsius over the treatment time.

[0038] Figure 5 The graph shows the change in peroxide value of walnut oil in each group after high-temperature treatment at 200-205 degrees Celsius over the treatment time.

[0039] Among them, Group A was the blank control group, Group B was the TBHQ sample group (TBHQ added to the oil at a rate of 0.2‰), Group C was the sample group of Example 2 (TBHQ added to the oil at a rate of 0.7‰), and Group D was the sample group of Comparative Example 2, which is Chinese Patent CN103767042A, Example 5, where an antioxidant sample group (TBHQ added to the oil at a rate of 1‰) was prepared.

[0040] Figure 6 Images of solutions from Example 1 sample group diluted in sunflower seed oil at ratios of 1:100 and 1:1000. Detailed Implementation

[0041] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0042] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0043] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0044] The fat-soluble rosemary extract, water-soluble rosemary extract, and water-dispersible rosemary oil of this invention are produced by Hainan Shupu Biotechnology Co., Ltd. They can be substituted by products from other manufacturers with the same content of effective ingredients and the same oil-water dispersibility, and can also achieve the specific implementation effect of this invention.

[0045] The fat-soluble rosemary extract and water-soluble rosemary extract of the present invention are obtained by steam distillation of dried rosemary leaves to separate oil and water, obtaining rosemary oil, and extracting the remaining residue with ethanol. After concentration, refining and drying, fat-soluble rosemary extract and water-soluble rosemary extract are obtained respectively.

[0046] Water-dispersible rosemary oil is obtained by steam distillation of rosemary oil, which is then fully dissolved with fat-soluble rosemary extract, filtered to remove impurities, and homogenized and emulsified with emulsifiers such as sucrose fatty acid esters and / or caprylic / capric glycerides. It can be replaced by products with equivalent effects, such as water-dispersible microencapsulated rosemary oil.

[0047] Example 1

[0048] An antioxidant suitable for high-temperature oil oxidation prevention, with the following formulation:

[0049]

[0050] The steps are as follows:

[0051] 1. Take 20 parts of glycerol aqueous solution and add it to No. 1 homogenizing emulsification tank. Add 12 parts of water-soluble rosemary extract, 3 parts of citric acid and 1 part of phytic acid. Add 4 parts of enzymatically hydrolyzed soybean lecithin from the emulsifier. Stir continuously and heat to 80°C. After dissolving, stop heating to obtain solution A.

[0052] 3. When solution A is cooled to 60°C after heating is stopped, water-dispersible rosemary oil is slowly added to solution A while continuously stirring to emulsify and dissolve. The stirring speed is 5000r / min-6000r / min and the emulsification time is 25min, resulting in O / W type emulsion B.

[0053] 4. Take 15 parts of phospholipid and 25 parts of rapeseed oil and add them to the No. 2 homogenizing emulsification tank. Add 10 parts of fat-soluble rosemary extract, 3 parts of mono- and diglyceride fatty acid esters and 1 part of propylene glycol fatty acid ester from the emulsifier. Stir constantly and heat to 75°C. After dissolving, stop heating to obtain solution C.

[0054] 5. When the temperature of solution C drops to 45℃, slowly add O / W type emulsion B to solution C while stirring continuously at a speed of 800-1000 r / min for 15 min. After cooling to room temperature, the rosemary-type multi-emulsion antioxidant is obtained.

[0055] Product oil solubility test:

[0056] Add 0.1g-1.0g of rosemary-type multi-emulsion antioxidant to 100g of sunflower seed oil. After shaking well, the sample is evenly dispersed. The main body of the solution is pale yellow to yellow, and it is in the form of a very light blue-white emulsion to an emulsion. No precipitate is observed after centrifugation at 4000r / min for 15min. No precipitate is observed at the bottom or top of the solution within 3 days at room temperature.

[0057] Product stability test under normal temperature and light protection storage

[0058]

[0059] Comparative test of antioxidant effects

[0060] Key points of the experimental design: The suitable frying temperature for French fries is 165-185 degrees Celsius. Based on the fact that the acid value and carbonyl value of fried foods change relatively little during their normal shelf life, while the peroxide value rises slowly, the carbonyl value of the oil in the French fries was determined after frying. A 60-degree Celsius oven was used to accelerate the process and measure the peroxide value; an oil oxidation stability tester was used to determine the oil oxidation induction time; and carbonyl value was measured in part of the experiment.

[0061] 3 kg of sunflower seed oil was taken from each group. Group A had no additives added; Group B had 0.6 g of TBHQ (pre-diluted and dissolved from 3 kg of oil, final addition amount 0.2‰); Group C had 2.1 g of the product from Example 1 (pre-diluted and dissolved from 3 kg of oil, final addition amount 0.7‰); and Group D had 2.1 g of the product from Comparative Example 1 (pre-diluted and dissolved from 3 kg of oil, final addition amount 0.7‰). All oils were added to a 304 stainless steel deep fryer, and the oil temperature was raised to 185-190 degrees Celsius. Equal weights of the same batch of commercially available French fries (without any additives) were added, and each batch was fried for the same time (9 min). Frying was carried out for 6 hours per day, for a total of 12 batches over 3 days. After frying each day, equal weights of oil and all fried French fries were stored in a refrigerator at 4 degrees Celsius for subsequent processing and testing. Store the remaining oil in an airtight container. Before frying on the second day, add the same type of new oil to a total of 3 kg (the weight difference of the newly added oil between different groups should be ≤10 g). Repeat the process until finished.

[0062] After frying, the samples were subjected to oven accelerated drying test, carbonyl value test, and oil oxidation stability test, respectively. The fried French fries were processed in accordance with national standards.

[0063] Depend on Figure 1 It can be seen that the oxidation induction time of the vegetable oils in each sample group decreased to varying degrees with the extension of the high-temperature treatment time at 185℃. The experimental group of Example 1, which was prepared into a multiple emulsion, was able to better control the slow release of active ingredients, and the rate of decrease in the oxidation induction time of the oil with the frying time was slower, which was better than the TBHQ group. However, the amount of active ingredient added in the experimental group of Comparative Example 1 was the same as that in the experimental group of Example 1. Tea polyphenols were used to replace water-soluble rosemary extract, and ethanol was used as a solvent to reduce the proportion of phospholipids in the oil mixture. As a result, the active ingredients were thermally degraded in the presence of ethanol, and water-soluble antioxidants such as tea polyphenols were easily precipitated due to the volatilization of ethanol solvent and the decrease in solubility in the oil. Therefore, the overall antioxidant effect was lower than that of the experimental group of Example 1 and Group B (TBHQ).

[0064] Depend on Figure 2 It can be seen that the experimental group of Example 1 and the experimental group of Comparative Example 1 are more effective in inhibiting the generation of carbonyl compounds in high-temperature oils. Moreover, in the experimental group of Example 1, which has undergone multiple emulsion processing, the rate of increase of carbonyl valence of oils is slower throughout the entire sample processing, indicating that the slow release of multiple emulsions has a better inhibitory effect on the generation of carbonyl compounds in high-temperature oils.

[0065] Table 1. Results of peroxide value of oil in French fries under accelerated oven drying conditions.

[0066]

[0067]

[0068] As shown in Table 1 above, the peroxide value of the French fries oil in the Example 1 experimental group was the lowest overall after frying, superior to the TBHQ group and significantly better than the Comparative Example 1 experimental group. In the accelerated testing, the peroxide value increased relatively slowly, and the longer the frying time, the more significant the difference in peroxide value compared to the Comparative Example 1 experimental group. The longer the frying time in the Comparative Example 1 experimental group, the faster the peroxide value increased in the accelerated testing, indicating that the longer the frying time, the more severe the decrease in antioxidant effect caused by the consumption or precipitation of antioxidant components in the Comparative Example 1 experimental group. In the later stages of the accelerated testing, the TBHQ group did not show a significant advantage over the Example 1 experimental group, indicating that the Example 1 experimental group was not inferior to the TBHQ group in terms of product shelf life. According to currently available research data, at lower temperatures, TBHQ has outstanding antioxidant capacity in oils, and very few natural antioxidants and their compound products can achieve the same level. Therefore, this also verifies that the antioxidants in the Example 1 experimental group have practical technical effects in terms of sustained and controlled release and oil solubility stability. This invention demonstrates that the rosemary-type multi-emulsion antioxidant, prepared using fat-soluble rosemary extract, water-soluble rosemary extract, water-dispersible rosemary oil, emulsifiers (enzymatically hydrolyzed soybean lecithin, mono- and diglyceride fatty acid esters, propylene glycol fatty acid esters, etc.), an oil mixture, and glycerol aqueous solution as a solvent, can delay oil oxidation at high temperatures and effectively delay rancidity of oils in fried foods during room temperature storage. It can also reduce the formation of carbonyl compounds, exhibiting significant advantages in food safety, convenience, and overall economic benefits.

[0069] Example 2

[0070] An antioxidant suitable for high-temperature oil oxidation prevention, with the following formulation:

[0071]

[0072]

[0073] The steps are as follows:

[0074] 1. Take 25 parts of acetic acid and add it to the No. 1 homogenizing emulsification tank. Add 15 parts of water-soluble rosemary extract, 0.5 parts of citric acid and 2 parts of phytic acid. Add 6.5 parts of modified soybean lecithin from the emulsifier. Stir continuously and heat to 85°C. After dissolving, stop heating to obtain solution A.

[0075] 3. When solution A is cooled to 70°C after heating is stopped, water-dispersible rosemary oil is slowly added to solution A while continuously stirring to emulsify and dissolve. The stirring speed is 4000r / min-5000r / min and the emulsification time is 30min, resulting in O / W type emulsion B.

[0076] 4. Take 20 parts of phospholipid and 10 parts of rapeseed oil and add them to the No. 2 homogenizing emulsification tank. Add 9 parts of fat-soluble rosemary extract, 1.5 parts of mono- and diglycerides of fatty acids and 2.5 parts of citric acid fatty acid glycerides from the emulsifier. Stir constantly and heat to 65°C. After dissolving, stop heating to obtain solution C.

[0077] 5. When the temperature of solution C drops to 50℃, emulsion B is slowly added to solution C while stirring continuously at a speed of 600-800 r / min for 20 min. After cooling to room temperature, rosemary-type multi-emulsion antioxidant is obtained.

[0078] The antioxidant obtained in Example 2 showed good dispersibility and stability in walnut oil at concentrations of 0.1g-1.0g after oil solubility and storage at room temperature away from light. No obvious precipitation or stratification was observed during storage at room temperature away from light for 6 months. The stored antioxidant was uniformly dispersed in walnut oil and showed no precipitation or sedimentation within 3 days.

[0079] Comparative test of antioxidant effects

[0080] Take 3 kg of walnut oil respectively. Group A: No additives added. Group B: Add 0.6 g of TBHQ (previously diluted and dissolved from 3 kg of oil, final addition amount: 0.2‰). Group C: Add 2.1 g of Example 2 product (previously diluted and dissolved from 3 kg of oil, final addition amount: 0.7‰). Group D: Add 3 g of Comparative Example 2 product (previously diluted and dissolved from 3 kg of oil, final addition amount: 1‰). Add each group's oil to a 304 stainless steel deep fryer, heat the oil to 200-205 degrees Celsius, and add the same batch of commercially available noodles (without any antioxidant additives), each batch with equal weight, frying for the same time (3 min), for a total of 12 batches, for a total frying time of 40 min. No new oil is added before the frying is completed. After frying for 20 min and 40 min, take an equal weight of oil and all fried noodles during the frying process and store them in a refrigerator at 4 degrees Celsius for subsequent processing and testing.

[0081] After processing, the walnut oil was subjected to tests for oil oxidation stability, iodine value, peroxide value, and other indicators.

[0082] Depend on Figure 3It can be seen that walnut oil treated at 200-205 degrees Celsius for 20-40 minutes, without the addition of any antioxidants, exhibits a particularly short induction time. All experimental groups with added antioxidants showed good antioxidant effects. The induction time of the TBHQ group was 3.2-2.93 times that of the control group, the experimental group of Example 2 was 3.16-2.85 times that of the control group, and 0.98-0.97 times that of the TBHQ group. The experimental group of Comparative Example 2 was 1.66-1.7 times that of the control group. The slightly shorter induction time of the Experimental Group of Example 2 indicates that the antioxidant effect of the walnut oil treated at 200 degrees Celsius for a shorter time is close to that of TBHQ and significantly better than that of the Experimental Group of Comparative Example 2.

[0083] Depend on Figure 4 It can be seen that during high-temperature treatment, the unsaturated fatty acid content in walnut oil decreases due to reactions such as hydrolysis, oxidation, and polymerization, resulting in a downward trend in the iodine value of the walnut oil. The iodine value of the experimental group in Example 2 remained consistently high, indicating that it effectively protects the unsaturated fatty acids in the walnut oil. The iodine value of the experimental group in Comparative Example 2 was lower than that in Example 2 but higher than that in the TBHQ group, indicating that the natural antioxidant, mainly composed of rosemary extract, can better protect unsaturated fatty acids at high temperatures, and the protective effect of the experimental group in Example 2 is better than that in Comparative Example 2.

[0084] Depend on Figure 5 It can be seen that the peroxide value of walnut oil increased rapidly after high-temperature treatment at 200-205 degrees Celsius, while the peroxide values ​​of the experimental groups with added antioxidants were relatively lower. Among them, the peroxide value level of the experimental group of Example 2 was relatively the lowest, while the peroxide value levels of the TBHQ group and the experimental group of Comparative Example 2 were relatively close. This indicates that during the high-temperature treatment, the antioxidant effect of the experimental group of Example 2 was better than that of TBHQ and the experimental group of Comparative Example 2, and it can provide better protection for walnut oil at high temperatures.

[0085] Therefore, in oils that are exposed to higher temperatures and are more easily oxidized in a short period of time, the synergistic effect of fat-soluble rosemary extract and water-soluble rosemary extract, along with the use of water-dispersible rosemary oil to enhance the antioxidant effect and provide aroma enhancement, and through a scheme that improves the solubility stability of water-soluble rosemary extract in high-temperature oils, the overall antioxidant effect is no less than that of TBHQ and significantly better than that of the comparative experimental group 2, providing a relatively better overall antioxidant protection effect.

[0086] Comparative Example 1

[0087] An antioxidant suitable for high-temperature oil oxidation prevention, with the following formulation:

[0088]

[0089]

[0090] The steps are as follows:

[0091] 1. Take 20 parts of ethanol and add them to No. 1 homogenizing emulsification tank. Add 12 parts of tea polyphenols, 3 parts of citric acid and 1 part of phytic acid. Add 4 parts of enzymatically hydrolyzed soybean lecithin from the emulsifier. Stir continuously and heat to 80°C. After dissolving, stop heating to obtain solution A.

[0092] 3. When solution A is cooled to 60°C after heating is stopped, water-dispersible rosemary oil is slowly added to solution A while continuously stirring to emulsify and dissolve. The stirring speed is 5000r / min-6000r / min and the stirring time is 25min, to obtain solution B.

[0093] 4. Take 2 parts of phospholipid and 38 parts of rapeseed oil and add them to the No. 2 homogenizing emulsification tank. Add 10 parts of fat-soluble rosemary extract, 3 parts of mono- and diglyceride fatty acid esters and 1 part of propylene glycol fatty acid ester from the emulsifier. Stir constantly and heat to 75°C. After dissolving, stop heating to obtain solution C.

[0094] 5. When the temperature of solution C drops to 45℃, slowly add solution B to solution C while stirring continuously at a speed of 800-1000 r / min for 15 min. After cooling to room temperature, solution D is obtained.

[0095] Testing revealed that when the antioxidant obtained in Comparative Example 1 was added to sunflower seed oil and treated at a high temperature of 185-190℃, the resulting potato oil was significantly inferior to the group in Example 1 in terms of oxidation induction time, oven accelerated testing, and carbonyl value testing. Adjusting the type of solvent, water-soluble antioxidant, and oil mixture ratio did not yield a stable emulsion. The emulsion could not be better and more uniformly dispersed when used in oils, and the active ingredients were easily degraded in the presence of ethanol and under heat. The product had low fluidity and stability, resulting in poor antioxidant effect.

[0096] Comparative Example 2

[0097] According to Chinese Patent CN103767042A, Example 5, an antioxidant was prepared and added to walnut oil. The oil was then treated at a high temperature of 200-205 degrees Celsius. The walnut oil treated with this antioxidant showed significantly worse performance than that of Example 2 in terms of oxidation induction time, iodine value, and peroxide value. This method used a combination of natural vitamin E, rosemary extract, and tea polyphenols, with a solvent as a dissolving agent. However, the high-temperature antioxidant effect of natural vitamin E was not good, and the high-temperature stability of tea polyphenols was poor, making them prone to degradation and browning. As the solvent evaporated, the polyphenols would precipitate out, which could not effectively improve the dispersibility and stability of the antioxidant in the oil, thus affecting the final antioxidant effect.

[0098] Comparative Example 3

[0099] An antioxidant suitable for high-temperature oil oxidation prevention, with the following formulation:

[0100]

[0101] The steps are as follows:

[0102] 1. Take 20 parts of glycerol aqueous solution and add it to No. 1 homogenizing emulsification tank. Add 3 parts of citric acid and 1 part of phytic acid. Add 4 parts of enzymatically hydrolyzed soybean lecithin from the emulsifier. Stir continuously and heat to 80°C. After dissolving, stop heating to obtain solution A.

[0103] 3. When solution A is cooled to 60°C after heating is stopped, water-dispersible rosemary oil is slowly added to solution A while continuously stirring to emulsify and dissolve. The stirring speed is 5000r / min-6000r / min and the emulsification time is 25min, resulting in O / W type emulsion B.

[0104] 4. Take 15 parts of phospholipid and 25 parts of rapeseed oil and add them to the No. 2 homogenizing emulsification tank. Add 22 parts of fat-soluble rosemary extract, 3 parts of mono- and diglyceride fatty acid esters and 1 part of propylene glycol fatty acid ester from the emulsifier. Stir continuously and heat to 75°C. Some components cannot dissolve. Stop heating and filter to obtain solution C.

[0105] 5. When the temperature of solution C drops to 45℃, slowly add O / W type emulsion B to solution C while stirring continuously at a speed of 800-1000 r / min for 15 min. After cooling to room temperature, antioxidant solution D is obtained.

[0106] Testing revealed that the sample in Comparative Example 3 had an excessively high amount of fat-soluble rosemary extract, which could not be completely dissolved and required filtration to remove insoluble matter. The sample was almost non-flowing, and after 6 months of storage, its flowability and stability did not reach the same level as the sample in Example 1. Using the antioxidant obtained in Comparative Example 3, added to sunflower seed oil in the same amount as in Example 1, the oil oxidation stability was tested. The oxidation induction time of the sample group in Comparative Example 3 was 0.665 times that of the sample group in Example 1. Therefore, water-soluble rosemary extract cannot be replaced by an equal amount of fat-soluble rosemary extract. In high-temperature frying environments, water-soluble and fat-soluble rosemary extracts exhibit a synergistic effect, and a single fat-soluble antioxidant cannot achieve a better antioxidant effect.

[0107] Sensory evaluation comparison test

[0108] Sensory evaluations were conducted on the French fries and noodles from Examples 1 and 2, and Comparative Examples 1 and 2, after high-temperature treatment. Evaluations were performed on five aspects: aroma, color, texture, crispness, and likability. The French fries and noodles from Examples 1 and 2 were superior to those from Comparative Examples 1 and 2 in aroma, color, texture, and likability. In particular, the aroma of the fried products from Examples 1 and 2 was unique, with a slight hint of herbal fragrance, exhibiting a special complex flavor. The crispness was similar. The antioxidants in the rosemary-type multi-emulsion obtained by using fat-soluble rosemary extract, water-soluble rosemary extract, water-dispersible rosemary oil, emulsifiers (glycerol, phospholipids and derivatives, mono- and diglyceride fatty acid esters, propylene glycol fatty acid esters, etc.), chelating agents, and oil mixtures, along with an aqueous solution of glycerol as a solvent, significantly improved the sensory quality of the French fries and noodles during high-temperature frying, resulting in excellent sensory evaluations.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An antioxidant suitable for high-temperature oil and fat oxidation, characterized in that, The ingredients include the following parts by weight: 5-15 parts fat-soluble rosemary extract, 5-15 parts water-soluble rosemary extract, 5-10 parts water-dispersible rosemary oil, 5-15 parts emulsifier, 30-50 parts oil mixture, 15-25 parts solvent and 0.5-5 parts chelating agent; The emulsifier includes at least one of glycerol, phospholipids and their derivatives, mono- and diglycerides of fatty acids, glycerides of fatty acids in citrate, propylene glycol fatty acid esters, or diacetyl tartaric acid mono- and diglycerides. The oil mixture consists of phospholipids and rapeseed oil in a mass ratio of 0.5~2:0.5~2; The method for preparing the antioxidant suitable for high-temperature oil oxidation includes: Step S1: Dissolve the water-soluble rosemary extract in a solvent, a chelating agent, and a partial emulsifier to prepare solution A; Step S2: Water-dispersible rosemary oil is added to solution A and stirred to emulsify and dissolve, resulting in an O / W type emulsion B; Step S3: Dissolve the fat-soluble rosemary extract into solution C using an oil mixture and the remaining emulsifier; Step S4: By mixing and emulsifying O / W type emulsion B and solution C, a multi-emulsion type antioxidant is obtained.

2. An antioxidant suitable for high-temperature oil and fat oxidation according to claim 1, characterized in that, The ingredients include the following parts by weight: 9-10 parts of fat-soluble rosemary extract, 12-15 parts of water-soluble rosemary extract, 6-8 parts of water-dispersible rosemary oil, 7-11 parts of emulsifier, 30-40 parts of oil mixture, 20-25 parts of solvent and 2-4 parts of chelating agent.

3. An antioxidant suitable for high-temperature oil and fat oxidation according to claim 1 or 2, characterized in that, The emulsifier is a phospholipid and its derivatives, mono- and diglycerides of fatty acids, and propylene glycol fatty acid esters in a mass ratio of 0.5-4:0.5-4:0.5-1.5; or the emulsifier is a phospholipid and its derivatives, mono- and diglycerides of fatty acids, and citrate fatty acid glycerides in a mass ratio of 0.5-4:0.5-4:0.5-1.

5. The solvent is at least one of water, propylene glycol, glycerol, acetic acid, phytic acid, or ethyl acetate; The chelating agent is citric acid and / or phytic acid; The phospholipids and their derivatives are phospholipids and / or enzymatically hydrolyzed soybean phospholipids and / or modified soybean phospholipids.

4. A method for preparing an antioxidant suitable for high-temperature oil oxidation according to any one of claims 1 to 3, characterized in that, include: Step S1: Dissolve the water-soluble rosemary extract in a solvent, a chelating agent, and a partial emulsifier to prepare solution A; Step S2: Water-dispersible rosemary oil is added to solution A and stirred to emulsify and dissolve, resulting in an O / W type emulsion B; Step S3: Dissolve the fat-soluble rosemary extract into solution C using an oil mixture and the remaining emulsifier; Step S4: By mixing and emulsifying O / W type emulsion B and solution C, a multi-emulsion type antioxidant is obtained.

5. The preparation method according to claim 4, characterized in that, In step S1, the emulsifier is enzymatically hydrolyzed soybean lecithin and / or modified soybean lecithin; in step S3, the emulsifier is mono- and diglyceride fatty acid esters and propylene glycol fatty acid esters, or the emulsifier is mono- and diglyceride fatty acid esters and citrate fatty acid glycerides.

6. The preparation method according to claim 4, characterized in that, The main active ingredients of the water-dispersible rosemary oil added in step S2 are rosemary oil and fat-soluble rosemary extract. Rosemary oil also acts as a solvent to dissolve and disperse the fat-soluble rosemary extract.

7. The preparation method according to claim 4, characterized in that, The mass ratio of the fat-soluble rosemary extract in the water-dispersible rosemary oil added in step S2 to the fat-soluble rosemary extract added in step S3 is 0.1-1:1-2.

8. The preparation method according to claim 4, characterized in that, In step S1, the solvent, chelating agent, partial emulsifier and water-soluble rosemary extract are mixed, stirred and heated to 60-85℃.

9. The preparation method according to claim 4, characterized in that, In step S2, when the temperature of solution A is 60-70℃, water-dispersible rosemary oil is slowly added to solution A, and stirring is continued at 3000-8000 r / min for 15-30 min. In step S3, the oil mixture is taken, fat-soluble rosemary extract and the remaining emulsifier are added, stirred, and heated to 60-85℃. In step S4, when the temperature of O / W emulsion B and solution C drops below 55℃, O / W emulsion B is slowly added to solution C, and stirring is continued at 600-2000 r / min for 5-20 min.

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