Natural high-color and high-stability chili oil and preparation method thereof

Abstract

The invention discloses natural high-color and high-stability chili oil and a preparation method thereof. Through ultrasonic combined microwave treatment, the color value and capsaicin content of the chili oil are remarkably improved, and the color is brighter. The method comprises the following steps: mixing mature and dried capsicum annuum and capsicum frutescens serving as raw materials according to a mass ratio of 2: 1, crushing, and screening with a 80-mesh screen, so as to obtain chili powder; hot oil is added into the chili powder, the oil temperature is 85-88 DEG C, and the mass volume ratio of the chili powder to the hot oil is (1-2): (8-9); uniformly stirring, performing ultrasonic combined microwave treatment for 20 minutes, and performing filtering and centrifugal treatment to obtain the high-color and high-stability chili oil. The chili oil prepared by the invention has more excellent color stability, flavor and sensory quality, can be widely applied to various fields of food, and provides a technical solution for extraction of capsochrome and product processing.

Description

Technical Field

[0001] This invention relates to the field of condiment preparation technology, specifically a method for preparing natural, high-color, and highly stable chili oil. Background Technology

[0002] Chili peppers (Capsicum spp.) are annual or perennial herbaceous plants belonging to the Solanaceae family. They are one of the most widely cultivated and used seasoning vegetables globally. my country is the world's largest producer and consumer of chili peppers, with extensive planting areas, abundant varieties, and a complete industrial chain encompassing fresh peppers, dried peppers, chili powder, chili sauce, chili oil, and other products. Chili peppers are rich in various active ingredients such as capsaicin, vitamin C, carotenoids, and phenolic compounds. These components not only determine the vibrant color and unique flavor of chili peppers but also endow them with certain antioxidant and metabolic-promoting physiological activities. Chili oil, made primarily from chili peppers, is characterized by its bright red color, rich aroma, and pure flavor, and is therefore widely used in catering, condiments, and snack foods, enjoying high market demand and application value.

[0003] The quality of chili oil primarily depends on its color, flavor, and storage stability. Existing chili oils commonly suffer from problems during processing and storage, such as insufficient pigment release, pigment oxidation and degradation, dull color, or precipitation. Especially under light or high-temperature conditions, capsanthin is easily oxidized and decomposed, leading to a decrease in color value and a decline in appearance. Furthermore, traditional high-temperature roasting or long-term extraction processes easily cause the degradation of heat-sensitive components (such as capsanthin and capsaicin), thus affecting the product's color stability and flavor retention. Therefore, how to efficiently extract chili pigments at lower temperatures while maintaining system stability has become a key technical problem that urgently needs to be solved in the field of chili oil preparation. Summary of the Invention

[0004] To overcome the problems of unstable color, easy pigment degradation, and quality decline in existing chili oil products during processing and storage, this invention provides a natural, high-color, and highly stable chili oil and its preparation method. Using dried chili peppers and corn oil as the main raw materials, and combining ultrasonic and microwave processing technologies, efficient extraction and system stabilization of chili pigments and flavor substances are achieved. Through low-temperature pulverization, temperature-controlled oil immersion, ultrasonic cavitation, and the synergistic effect of microwaves, the cell structure of chili peppers is broken down under low energy consumption conditions, allowing fat-soluble components (including capsaicin and other pigments) to fully dissolve, thereby improving the color value and antioxidant properties of the chili oil. Subsequently, suspended impurities are removed through pressure filtration and centrifugal purification processes, yielding a bright, clear, and transparent natural chili oil with excellent color stability.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] This invention first discloses a method for preparing natural, high-color, and highly stable chili oil, comprising:

[0007] S1, Raw material pretreatment: Select fresh long peppers and horn peppers, dry them to constant weight, and then crush them to obtain chili powder for later use;

[0008] S2, Oil soaking: Add hot oil to chili powder and stir well. After soaking for 5 minutes, stir continuously to obtain the oil-soaked substance for later use.

[0009] S3, Ultrasonic and Microwave Treatment: The oil-impregnated material is first ultrasonically treated, then microwaved, and after cooling, an oil mixture is obtained.

[0010] S4, Filtration: The oil mixture is pressure filtered through a pressure filtration unit to obtain filtered chili oil;

[0011] S5, Centrifugation: The filtered chili oil is processed through a tubular centrifuge to obtain high-color, high-stability chili oil.

[0012] Furthermore, in step S1, the mass ratio of dried long peppers and horn peppers to constant weight is 2:1; the pulverizing temperature is controlled below 35℃, the pulverizing time is 15-25s, and the chili powder is passed through an 80-mesh sieve.

[0013] Further, the temperature of the hot oil in step S2 is 85~88℃; the mass-volume ratio of the chili powder to the hot oil is (1~2):(8~9).

[0014] Further, the ultrasonic treatment conditions in step S3 are: power 400W, treatment time 16-18min; the microwave treatment conditions are: power 400W, treatment time 3-5min.

[0015] Further, the pressure filtration in step S4 is as follows: the operating pressure is 0.2-0.4 MPa, and a 200-mesh nylon (food grade) filter screen is used for filtration.

[0016] Furthermore, the centrifugation conditions described in step S5 are: centrifugal force 16000×g, flow rate 150-300L / h.

[0017] The present invention also discloses a natural high-color, high-stability chili oil prepared according to any of the above preparation methods.

[0018] The beneficial effects of this invention are as follows:

[0019] (1) High-efficiency extraction of capsicum pigments and active ingredients is achieved under low temperature conditions, avoiding component degradation caused by traditional high-temperature processes;

[0020] (2) By combining ultrasonic and microwave treatment, the pigment release efficiency and the stability of pigments in the oil phase are significantly improved, the color value and capsaicin content of chili oil are significantly increased, and the color is brighter.

[0021] (3) The chili oil obtained after centrifugation and filtration is clear and transparent, and is not prone to sedimentation during storage;

[0022] (4) The product has a high color value and excellent light and heat stability, and can maintain its color and flavor quality for a long time at room temperature. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the preparation process of the natural, high-color, and highly stable chili oil of this invention.

[0024] Figure 2 This is a product image of the natural, high-color, and highly stable chili oil of this invention.

[0025] Figure 3 This is a comparison chart of the indicators of the natural high-color and high-stability chili oil of this invention with those of commercial products, A (viscosity, sensory evaluation), B (L, a, b values), and C (comparison chart of capsaicin storage stability).

[0026] Figure 4 This is a comparison diagram of the storage light stability of capsanthin in the natural high-color, high-stability chili oil of this invention and commercially available products.

[0027] Figure 5 This is a comparison chart of the thermal stability of capsanthin in the natural, high-color, and high-stability chili oil of this invention with that of commercially available products during storage. Detailed Implementation

[0028] Comparative Example 1

[0029] (1) Raw materials: Cut the selected dried red chilies into 1cm segments and separate the chili skin and seeds;

[0030] (2) Stir-frying chili skin: Add 100g of cooking oil to a wok and heat for 2 minutes to bring the oil temperature to about 200℃; then add 5kg of chili skin and 150g of cooking oil and stir-fry for 20 minutes. Stir constantly during the stir-frying process. After turning off the heat, keep the temperature warm for 15 minutes to obtain the stir-fried chili skin for later use.

[0031] (3) Roasting chili seeds: Add 300g of cooking oil and 10kg of chili seeds to a wok and roast at 150℃ for 20 minutes. Stir constantly during the roasting process. After turning off the heat, keep the temperature warm for 20 minutes to obtain roasted chili seeds for later use.

[0032] (4) Crushing process: Mix and crush the fried chili skin and fried chili seeds for 10 minutes to obtain a chili mixture for later use;

[0033] (5) Frying treatment: Heat 100kg of cooking oil in a wok to 220℃, add 3kg of ginger and fry for 15min; then add 5kg of scallions and fry for 15min; the frying oil temperature for ginger and scallions is 145℃; then add chili mixture and continue to fry at 160℃ for 15min to obtain the mixture for later use.

[0034] (6) Filtration: The mixture is filtered to obtain the initial chili oil and the mixture residue;

[0035] (7) Low temperature extraction: Pump the initial chili oil into the extraction pot for low temperature extraction. When the oil temperature drops to 120℃, stir and extract for 20 minutes. When the oil temperature drops to 75℃, let it stand for 48 hours to extract the semi-finished chili oil for later use.

[0036] (8) Bottling: After the semi-finished chili oil is treated to reduce its spiciness and settle for 1 month, it is bottled to obtain the finished chili oil.

[0037] Example 1

[0038] A method for preparing natural, high-color, and highly stable chili oil

[0039] (1) Raw material selection: Fresh, dried to constant weight long peppers and horn peppers are required. Ensure that the surface of the peppers is dry, without moisture, makes a crisp sound when lightly squeezed, and has no musty smell or impurities.

[0040] (2) Crushing: Weigh out dried long peppers and horn peppers, making their total mass account for 20% of the total material; the mass ratio of dried long peppers to horn peppers is 2:1 (m:m). Place both in a grinding mill and crush them at 35°C for 20 seconds, then pass them through an 80-mesh sieve to obtain chili powder.

[0041] (3) Heat the oil: Pour the corn oil into a double-layer heating pot and heat it to 86°C. The amount of oil added should not exceed 2 / 3 of its volume. After the oil is heated, keep the oil warm for later use.

[0042] (4) Oil soaking: Heated corn oil and chili powder are added to a food-grade 304 stainless steel mixing tank in a ratio of 8.5:1.5 (v:m) and mixed evenly. After soaking for 5 minutes, the mixing system is turned on to continuously stir evenly to obtain mixed oil.

[0043] (5) Ultrasonic and microwave treatment: Place the ultrasonic probe into the well-stirred oil mixture, set the ultrasonic power to 400w, and the ultrasonic treatment time to 17min. Then, treat the well-stirred oil mixture in a microwave oven at 400w for 4min.

[0044] Ultrasonic-microwave synergistic extraction technology significantly improves the extraction efficiency and quality of chili oil through a synergistic physical mechanism. Its core mechanism lies in the fact that the cavitation and mechanical effects of ultrasound effectively disrupt the cell wall structure of chili peppers, accelerating the release of intracellular oils and lipid-soluble components such as capsaicin and cinnamon. Simultaneously, the penetrability and bulk heating effect of microwaves cause the internal moisture to vaporize instantly, generating strong pressure that breaks down the cell walls from within, creating a pressure difference that powerfully drives the oil to seep out.

[0045] (6) Filtration: The cooled oil mixture after processing is transported to the filtration unit and pressurized (operating pressure 0.3 MPa) through a 200-mesh nylon (food grade) filter screen (pore size 75μm) to obtain coarsely filtered chili oil.

[0046] (7) Centrifugation: The coarsely filtered chili oil is centrifuged through a tubular centrifuge (centrifugal force of 16000×g, flow rate of 225 L / h) to obtain high-color and high-stability chili oil.

[0047] Example 2

[0048] A method for preparing natural, high-color, and highly stable chili oil

[0049] (1) Raw material selection: Fresh, dried to constant weight long peppers and horn peppers are required. Ensure that the surface of the peppers is dry, without moisture, makes a crisp sound when lightly squeezed, and has no musty smell or impurities.

[0050] (2) Crushing: Weigh out dried long peppers and horn peppers, making their total mass account for 20% of the total material; the mass ratio of dried long peppers to horn peppers is 2:1 (m:m). Place both in a grinding mill and crush them at 35°C for 15 seconds, then pass them through an 80-mesh sieve to obtain chili powder.

[0051] (3) Heat the oil: Pour the corn oil into a double-layer heating pot and heat it to 85°C. The amount of oil added should not exceed 2 / 3 of its volume. After the oil is heated, keep the oil warm for later use.

[0052] (4) Oil soaking: Heat the corn oil and chili powder in a ratio of 9:2 (v:m) into a food-grade 304 stainless steel mixing tank and mix evenly. After soaking for 5 minutes, turn on the mixing system and stir continuously until the mixture is evenly mixed to obtain the mixed oil.

[0053] (5) Ultrasonic and microwave treatment: Place the ultrasonic probe into the well-stirred oil mixture, set the ultrasonic power to 400w, and the ultrasonic treatment time to 18min. Then, microwave the well-stirred oil mixture in a microwave oven at 400w for 3min.

[0054] (6) Filtration: The cooled oil mixture after processing is transported to the filtration unit and pressurized (operating pressure 0.4 MPa) through a 200-mesh nylon (food grade) filter screen (pore size 75μm) to obtain coarsely filtered chili oil.

[0055] (7) Centrifugation: The coarsely filtered chili oil is centrifuged through a tubular centrifuge (centrifugal force is 16000×g, flow rate is 300 L / h) to obtain high-color and high-stability chili oil.

[0056] Example 3

[0057] A method for preparing natural, high-color, and highly stable chili oil

[0058] (1) Raw material selection: Fresh, dried to constant weight long peppers and horn peppers are required. Ensure that the surface of the peppers is dry, without moisture, makes a crisp sound when lightly squeezed, and has no musty smell or impurities.

[0059] (2) Crushing: Weigh out dried long peppers and horn peppers, making their total mass account for 20% of the total material; the mass ratio of dried long peppers to horn peppers is 2:1 (m:m). Place both in a grinding mill and crush them at 35°C for 25 seconds, then pass them through an 80-mesh sieve to obtain chili powder.

[0060] (3) Heat the oil: Pour the corn oil into a double-layer heating pot and heat it to 88°C. The amount of oil added should not exceed 2 / 3 of its volume. After the oil is heated, keep the oil warm for later use.

[0061] (4) Oil soaking: Heat the corn oil and chili powder in a ratio of 8:1 (v:m) into a food-grade 304 stainless steel mixing tank and mix evenly. After soaking for 5 minutes, turn on the stirring system and stir continuously until evenly mixed to obtain the mixed oil.

[0062] (5) Ultrasonic and microwave treatment: Place the ultrasonic probe into the well-stirred oil mixture, set the ultrasonic power to 400w, and the ultrasonic treatment time to 16min. Then, microwave the well-stirred oil mixture in a microwave oven at 400w for 5min.

[0063] (6) Filtration: The cooled oil mixture after processing is transported to the filtration unit and pressurized (operating pressure 0.2 MPa) through a 200-mesh nylon (food grade) filter screen (pore size 75μm) to obtain coarsely filtered chili oil.

[0064] (7) Centrifugation: The coarsely filtered chili oil is centrifuged through a tubular centrifuge (centrifugal force is 16000×g, flow rate is 150 L / h) to obtain high-color and high-stability chili oil.

[0065] Experimental Example 1

[0066] The physical properties of the chili oils prepared in Example 1 and Comparative Example 1 were measured.

[0067] Table 1. Test results of various indicators of naturally colored, highly stable chili oil.

[0068]

[0069] Analysis of Experimental Results

[0070] (1) Results and analysis of color value determination

[0071] Table 1 shows that the color value of the chili oil after combined treatment (sample of Example 1) was 2.21, which was approximately 25.57% higher than that of Comparative Example 1. The study indicates that the cavitation effect of ultrasound generates a powerful impact force, causing tiny vacuoles to form around chili cells and collapse instantly, resulting in strong mechanical shearing of the cells; microwaves utilize high-frequency electromagnetic waves to cause high-speed vibration and frictional heat generation of molecules within chili cells. The synergy of these two methods can rapidly and efficiently disrupt the structure of chili cells, making it easier for intracellular pigments to dissolve into the oil. Compared to traditional methods, this allows for the extraction of more pigments, thereby increasing the color value of the chili oil. A detailed visual color comparison of the two methods can be found in [link to relevant documentation]. Figure 2 The unprocessed left side is Comparative Example 1, and the combined processed right side is Example 1. Figure 2 It is evident that the color of the sample in Example 1 is significantly better than that in Comparative Example 1.

[0072] (2) Results and analysis of capsaicin content determination

[0073] As shown in Table 1, the capsaicin content of the chili oil after co-treatment (sample of Example 1) was 83.96%, which was approximately 14.5% higher than that of Comparative Example 1. The mechanical vibration of ultrasound can enhance the diffusion and mass transfer efficiency of substances within the system; microwaves intensify the molecular motion in chili peppers and oils, increasing molecular activity and collision frequency. More capsaicin can dissolve into the oil and disperse uniformly within the system, ultimately increasing the overall capsaicin content of the chili oil.

[0074] (3) Results and analysis of refractive index measurement

[0075] As shown in Table 1, after ultrasonic and microwave treatment, the refractive index of the chili oil prepared in Example 1 was not significantly different from that of Comparative Example 1, and was close to that of corn oil. This indicates that the fat-soluble components (such as capsaicin and pigments) in chili peppers were fully dissolved and the oil phase concentration was high.

[0076] (4) Results and analysis of peroxide value determination

[0077] Peroxide value is an indicator for measuring the content of hydroperoxides in oils. As shown in Table 1, the peroxide value of chili oil (sample of Example 1) after ultrasonic and microwave treatment was 47 mg / 100g. Compared with the peroxide value of 46 mg / 100g of the product of Comparative Example 1, it was not significantly increased. This indicates that the process can efficiently extract the functional components of chili while having minimal impact on the stability of the oil, and is reasonable.

[0078] (5) Results and analysis of DPPH and ABTS clearance rates

[0079] Enhanced antioxidant capacity is a crucial indicator for improving oil quality, especially for products like chili oil rich in unsaturated fatty acids. Stronger antioxidant activity can delay oxidative rancidity and extend shelf life. Table 1 shows that after combined treatment, the DPPH and ABTS removal rates of the chili oil sample prepared in Example 1 were 85.95% and 86.76%, respectively, representing increases of 5.8% and 8.3% compared to Comparative Example 1. The cavitation effect of ultrasound and the thermal effect of microwaves may disrupt the cell structure of chili peppers, making it easier for antioxidants such as phenolic substances, capsaicin, and their derivatives, originally encapsulated within the cells, to dissolve into the oil. The treatment process did not damage the antioxidants (e.g., due to high-temperature degradation); instead, it optimized the dissolution efficiency of the components through physical action, enhancing the antioxidant activity of the oil.

[0080] Experimental Example 2

[0081] The chili oil prepared in Example 1 was compared with commercially available chili oils.

[0082] Figure 3 A represents the sensory evaluation and viscosity values ​​of different samples. The sensory score of the sample in Example 1 was 4.3 and 6.5 points higher than that of Brand A and Brand B, respectively, and the viscosity values ​​were 223 mPa·s and 351 mPa·s higher, respectively.

[0083] Figure 3 B represents the color analysis results of different samples. The L* value of the sample in Example 1 increased by 34.6% and 37.9% compared with Brand A and Brand B, respectively, the a* value increased by 71.5% and 79.8% respectively, while the b* value decreased by 20% and 33.5% respectively, indicating that the sample in Example 1 has a brighter color and higher redness.

[0084] Figure 3 C represents the results of capsaicin storage stability experiments for different samples. Throughout the entire storage period, the capsaicin retention rate of the sample in Example 1 was significantly higher than that of Brand A and Brand B. After 9 days of storage, the capsaicin retention rate was 10% and 21% higher than that of Brand A and Brand B, respectively.

[0085] Figure 4The results of the photostability test for chili oil pigments are presented. As shown in the figure, under light conditions, the capsanthin retention rate of all samples showed a decreasing trend. However, the capsanthin retention rate of the sample from Example 1 was higher than that of Brand A and Brand B at all stages of storage. At the end of the test (9 days), the capsanthin retention rate of the sample from Example 1 was 15% and 24% higher than that of Brand A and Brand B, respectively, indicating that the combined ultrasonic-microwave treatment can enhance the photostability of chili oil, which helps maintain good color during storage.

[0086] Figure 5 The results of the capsanthin thermal stability test of chili oil at 4℃, 25℃, and 50℃ showed that although the pigment retention rate of each sample decreased over time at different temperatures, the pigment retention rate of the sample in Example 1 was higher than that of Brand A and Brand B at all temperatures and time points. Specifically, after storage at 4℃ for 9 days, the capsanthin retention rate of the sample in Example 1 was 14.67% and 6.71% higher than that of Brand A and Brand B, respectively; after storage at 25℃ for 9 days, the capsanthin retention rate of the sample in Example 1 was 11.93% and 10.19% higher than that of Brand A and Brand B, respectively; and after storage at 50℃ for 9 days, the capsanthin retention rate of the sample in Example 1 was 10.58% and 6.47% higher than that of Brand A and Brand B, respectively. The above data indicate that the ultrasonic-microwave combined processing technology used in this invention can significantly enhance the thermal stability of pigments in chili oil. It is speculated that the mechanism is that the ultrasonic-microwave combination promotes the full release of pigment components and makes the pigments and proteins form a more stable chemical structure, thereby enhancing the thermal stability of capsanthin in chili oil.

[0087] In summary, compared with commercially available chili oil products, the sample obtained in Example 1 is superior to Brand A and Brand B in terms of sensory quality, color, viscosity, capsaicin stability, and photothermal stability of capsanthin, demonstrating excellent overall quality.

Claims

1. A preparation method of natural high-color and high-stability chili oil, comprising: S1, raw material pretreatment: fresh linear peppers and horn peppers are dried to constant weight, and then crushed to obtain chili powder for use; S2, oil immersion: hot oil is added to the chili powder and stirred uniformly, and after 5 min of immersion and continuous stirring, an oil immersion product is obtained for use; S3, ultrasonic and microwave treatment: the oil immersion product is first subjected to ultrasonic treatment, and then subjected to microwave treatment, and after cooling, an oil mixture is obtained; S4, filtration: the oil mixture is subjected to pressure filtration through a pressure filtration unit to obtain filtered chili oil; S5, centrifugation: the filtered chili oil is subjected to centrifugation through a tubular centrifuge to obtain high-color and high-stability chili oil.

2. The preparation method of claim 1, wherein: the mass ratio of linear peppers to horn peppers dried to constant weight in step S1 is 2:1; the crushing temperature is controlled below 35℃, and the crushing time is 15-25 s; the chili powder is passed through an 80-mesh screen.

3. The preparation method of claim 1, wherein: the temperature of the hot oil in step S2 is 85-88℃; the mass-volume ratio of chili powder to hot oil is (1-2):(8-9).

4. The preparation method of claim 1, wherein: the ultrasonic treatment conditions in step S3 are: power 400w, and treatment time 16-18 min; the microwave treatment conditions are: power 400w, and treatment time 3-5 min.

5. The preparation method of claim 1, wherein: the pressure filtration in step S4 is: the operating pressure is 0.2-0.4 MPa, and a 200-mesh nylon filter screen is used for filtration treatment.

6. The preparation method of claim 1, wherein: the centrifugation treatment conditions in step S5 are: centrifugal force 16000xg, and flow rate 150-300 L / h.

7. Natural high-color and high-stability chili oil prepared by the preparation method of any one of claims 1-6.

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