A gardenia flower extract, a preparation method thereof and application thereof in edible essence

Abstract

The present application relates to the technical field of essence, in particular to a gardenia flower extract, a preparation method thereof and application of the gardenia flower extract in edible essence, the preparation method of the gardenia flower extract comprises the following steps: S1, raw material liquid nitrogen freezing fresh preservation pretreatment; S2, raw material pre-soaking; S3, primary ultrasonic-assisted extraction; S4, secondary ultrasonic-assisted extraction; S5, cold storage treatment and coarse filtration and centrifugation; S6, membrane separation and purification; S7, blending. The method significantly improves the aroma authenticity, freshness, reality and storage stability of the extract through liquid nitrogen freezing fresh preservation, low-temperature ultrasonic-assisted extraction, membrane separation and purification and calyx trace blending technology, and realizes high-value utilization of gardenia flower by-products. The prepared gardenia flower extract is obtained by grading extraction and trace blending of petals and calyces, has fresh, full, sweet and characteristic gardenia flower aroma, and has good solubility and storage stability in a food system.

Description

Technical Field

[0001] This invention relates to the field of flavor technology, specifically to a gardenia extract, its preparation method, and its application in edible flavorings. Background Technology

[0002] Gardenia flowers, with their delicate fragrance and unique sweet aroma, have broad application prospects in the field of food flavoring. Traditional methods for preparing gardenia flower extract mainly involve two key steps: pretreatment and extraction. However, existing technologies have varying degrees of shortcomings in each step.

[0003] Regarding pretreatment techniques, both low-temperature vacuum drying and freeze-drying processes significantly reduce the loss of volatile aromatic compounds in gardenia flowers during the process of embrittlement and moisture capture. The root cause lies in the fact that the continuous vacuuming by the vacuum pump and the condenser's capture and discharge of water vapor simultaneously remove a large amount of volatile aromatic components, resulting in incomplete aroma and a lack of top notes even at the pretreatment stage. Furthermore, these drying techniques are typically time-consuming, further exacerbating aroma loss and making it difficult to meet the production requirements of high-quality gardenia extract.

[0004] Regarding extraction technology, existing methods also have many shortcomings. 1) Steam distillation: Although simple to operate, prolonged high-temperature heating easily leads to the loss, oxidation, or isomerization of heat-sensitive aroma components (such as linalool and jasmine lactone), which is particularly damaging to top notes. The resulting essential oils lack freshness and authenticity, and the yield is generally low. 2) Organic solvent extraction: Commonly used organic solvents such as petroleum ether and hexane, although the yield is relatively high, there is a risk of solvent residue, and the desolvation process also damages aroma components. At the same time, the use of organic solvents is environmentally unfriendly and does not conform to the development trend of green and clean production. 3) Ordinary maceration or reflux extraction: The extraction time is long and the efficiency is low. During the extraction process, a large number of impurities (such as polysaccharides, proteins, colloids, etc.) co-dissolve with the target aroma components, causing the extract to easily become turbid and precipitate, resulting in poor stability. This seriously limits its application in the food industry, especially failing to meet the high clarity requirements of products such as transparent beverage systems.

[0005] In summary, existing gardenia extraction techniques generally suffer from problems such as distorted aroma, insufficient freshness, high impurity content, poor stability, and environmental unfriendliness. Therefore, developing a preparation method that can maximize the preservation of the natural aroma characteristics of gardenia and improve the quality and stability of the extract has significant practical application value. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art by providing a gardenia extract, its preparation method, and its application in edible flavorings. This method significantly improves the authenticity, freshness, physical feel, and storage stability of the extract through liquid nitrogen freezing for freshness preservation, low-temperature ultrasonic-assisted extraction, membrane separation purification, and micro-adjustment of the calyx, and also realizes the high-value utilization of gardenia by-products.

[0007] The objective of this invention is achieved through the following technical solution: a method for preparing gardenia flower extract, comprising the following steps: S1. Pretreatment of raw materials by freezing and locking freshness with liquid nitrogen: Select fresh gardenia flowers, remove impurities and flower stems, and retain the calyx; place the treated gardenia flowers and calyxes in two stainless steel containers respectively, add liquid nitrogen to 0.1-1cm above the material, and place them in a non-sealed container for 2-8 minutes. S2. Pre-soaking of raw materials: Place the pre-treated gardenia flowers and calyxes into two extraction tanks, add extraction solvent, and soak for 10-20 minutes. The extraction solvent should be refrigerated at 10-20℃ for 2-4 hours before use. S3. Initial ultrasonic-assisted extraction: At a temperature of 15℃-28℃, the gardenia flowers and calyxes soaked in step S2 were subjected to repeated ultrasonic extraction 2-4 times. Each ultrasonic treatment lasted 15-30 minutes, and the ultrasonic treatment was stopped and the soaking was maintained for 15-25 minutes until the last ultrasonic treatment was completed. After filtration, the initial gardenia flower extract solution and the initial calyx extract solution were obtained respectively. S4. Secondary ultrasonic-assisted extraction: At a temperature of 15℃-28℃, the gardenia flower material and calyx material in the tank after ultrasonic-assisted extraction in step S3 are subjected to repeated ultrasonic extraction 2-4 times. Each ultrasonic treatment lasts for 15-20 minutes. After each ultrasonic treatment, the ultrasonic treatment is stopped and the soaking is maintained for 15-25 minutes until the last ultrasonic treatment is completed. After filtration, secondary gardenia flower extract solution and secondary calyx extract solution are obtained. S5. Cold storage treatment, coarse filtration and centrifugation: Mix the first and second gardenia flower extract solutions evenly to obtain gardenia flower extract; mix the first and second calyx extract solutions evenly to obtain calyx extract; refrigerate the gardenia flower extract and calyx extract at 10-20℃ for 25-35 minutes; filter the refrigerated gardenia flower extract and calyx extract separately through a 180-220 mesh filter to remove flower residue; then centrifuge the filtrate to obtain gardenia flower extract concentrate and calyx extract concentrate, respectively. S6. Membrane separation and purification: Gardenia flower extract and calyx extract are processed sequentially through a three-stage membrane system of microfiltration, ultrafiltration and nanofiltration. The microfiltration and ultrafiltration permeate from gardenia flower are partially retained, and the microfiltration and ultrafiltration permeate from calyx are partially retained for later use. S7. Preparation: Mix the microfiltration permeate, ultrafiltration permeate, and nanofiltration retentate from gardenia flowers at a volume ratio of 1:(1.5-2.5):1 to obtain gardenia flower preparation solution; mix the microfiltration permeate, ultrafiltration permeate, and nanofiltration retentate from calyx flowers at a volume ratio of 1:(1.5-2.5):1 to obtain calyx preparation solution; add the calyx preparation solution to the gardenia flower preparation solution to obtain gardenia flower extract, wherein the amount of calyx preparation solution added accounts for 0.0008-0.0012% of the mass fraction of gardenia flower extract.

[0008] This invention involves several steps, including liquid nitrogen freezing for freshness preservation, low-temperature ultrasonic-assisted extraction, refrigeration, coarse filtration and centrifugation, and membrane separation purification of gardenia petals and calyxes. The liquid nitrogen freezing technique, used to treat the gardenia petals and calyxes separately, maximizes the preservation of volatile, heat-sensitive aroma components, resulting in an extract with a fresh, full, and sweet gardenia aroma. This process also embrittles the material for easier subsequent extraction. Furthermore, the extraction solvent is refrigerated before use to prevent the heat generated by molecular motion during subsequent ultrasonication from raising its temperature, which would otherwise lead to the loss of volatile substances. This method minimizes the loss of volatile aroma compounds. The extraction process alternates between stepwise ultrasonic extraction and low-temperature soaking. During ultrasonic extraction, molecular motion generates heat, raising the temperature of the extraction solvent. This increased solvent temperature accelerates the loss of volatile aroma compounds. To maintain the integrity of the aroma, the material is soaked in a static state after ultrasonic extraction for a period of time to lower the solvent temperature. This prevents the temperature rise caused by prolonged continuous ultrasonic extraction and avoids the loss of volatile aroma compounds due to ultrasonic heat generation, thus ensuring the integrity of the top notes. Refrigeration lowers the temperature of the extract immediately after ultrasonic extraction, retaining more volatile aroma compounds. It also allows for the separation of large molecules in the extract, facilitating subsequent filtration and centrifugation. A three-stage membrane separation purification process (microfiltration, ultrafiltration, and nanofiltration) is used to fractionate the extract. This not only removes large molecular impurities and colloidal substances, improving the stability of the extract, but also achieves cold concentration at room temperature through nanofiltration, avoiding the destruction of heat-sensitive aroma components. It is worth mentioning that the entire preparation process employs low-temperature (≤35℃) extraction and membrane separation concentration, avoiding the damage to aroma components caused by traditional thermal concentration or distillation. This improves the dissolution rate of gardenia aroma substances and further blends the aromas of gardenia petals and calyxes, maximizing the reproduction of the natural fragrance of the entire gardenia flower, resulting in a realistic and layered aroma. Finally, by blending different membrane-separated components of gardenia in a specific ratio and adding a trace amount of calyx extract, the resulting gardenia extract possesses a fresh, full-bodied, and sweet characteristic gardenia aroma, with rich aroma layers and a strong sense of realism.

[0009] Furthermore, in step S2, the extraction solvent is a food-grade ethanol-water mixture with a volume ratio of 6-8:3 and a material-liquid volume ratio of 1:18-22.

[0010] Furthermore, in step S3, at a temperature of 15-28℃, the gardenia flowers and calyxes soaked in step S2 are first subjected to ultrasonic extraction for 25-35 minutes, and after stopping the ultrasonic treatment, the soaking is maintained for 15-25 minutes; then ultrasonic treatment is performed for 10-20 minutes, and after stopping the ultrasonic treatment, the soaking is maintained for 15-25 minutes; finally, ultrasonic treatment is performed for 10-20 minutes, and after the ultrasonic treatment is completed, the initial gardenia flower extract solution and the initial calyx extract solution are obtained by filtration.

[0011] Furthermore, in step S4, at a temperature of 15-28℃, the gardenia flower material and calyx material in the tank after ultrasonic-assisted extraction in step S3 are first ultrasonically extracted for 15-25 minutes respectively. After stopping the ultrasonic treatment, the material is kept soaked for 15-25 minutes. Then, the material is ultrasonically treated for 10-20 minutes, and the ultrasonic treatment is stopped while the material is kept soaked for 15-25 minutes. Finally, the material is ultrasonically treated for 10-20 minutes. After the ultrasonic treatment is completed, the material is filtered to obtain secondary gardenia flower extract solution and secondary calyx extract solution.

[0012] Furthermore, in step S6, the microfiltration employs a ceramic membrane or tubular organic membrane with a pore size of 0.1-0.5 μm, and the operating pressure is 0.1-0.3 MPa. This microfiltration step effectively removes bacteria, fine particles, and some large-molecule polysaccharides and proteins, resulting in a clear and transparent microfiltration permeate.

[0013] Furthermore, in step S6, the ultrafiltration employs a spiral-wound organic membrane with a molecular weight cutoff of 5-20 kDa, and the operating pressure is 0.3-0.8 MPa. This ultrafiltration step selectively retains colloidal substances with larger molecular weights, such as proteins and pectin, ensuring the long-term stability of the extract during subsequent storage and application.

[0014] Furthermore, in step S6, the nanofiltration employs a solvent-resistant nanofiltration membrane with a molecular weight cutoff of 150-500 Da, operating at a pressure of 1.5-2.5 MPa. This nanofiltration step cold-concentrates the ethanol-water solution, utilizing the selective separation characteristics of the nanofiltration membrane at room temperature to effectively retain the target aroma components. Specifically, the molecular weights of key aroma components in gardenia are typically between 50 Da and 300 Da. Although some components have molecular weights lower than the nominal molecular weight cutoff of the nanofiltration membrane, these aroma components can still be efficiently retained by the nanofiltration membrane due to the interactions between the solute and solvent in the ethanol-water mixed solvent system (such as hydrogen bonding and hydrophobic interactions) and the hydrophobic properties of the membrane material itself. Simultaneously, water and small amounts of small-molecule acids and alcohols can pass through the nanofiltration membrane smoothly, thus achieving the dual effect of enriching the target aroma components and removing some undesirable odor precursors (such as certain low-molecular-weight organic acids). The entire process is carried out at room temperature without heating, which avoids the degradation or volatilization of heat-sensitive aroma components and significantly reduces energy consumption. It is a green, mild, and efficient concentration and purification method.

[0015] Furthermore, in step S7, the gardenia extract is pale yellow to pale yellow-green, possessing a fresh, full, and sweet gardenia aroma. Specifically, the gardenia flower blending liquid is pale yellow, the calyx blending liquid is green, and the calyx blending liquid is added to the gardenia flower blending liquid to obtain a gardenia extract that is pale yellow to pale yellow-green. The resulting extract is pale yellow to pale yellow-green in color, with a pure and stable aroma, making it suitable for use in various edible flavorings such as gardenia, green tea, and apple, significantly improving the overall aroma quality and palatability of the flavorings.

[0016] The present invention also provides a gardenia flower extract, which is prepared by the above-described method for preparing a gardenia flower extract.

[0017] The gardenia extract obtained by this invention possesses a fresh, full, and sweet gardenia aroma, with a pale yellow to pale yellow-green color. It is free of significant macromolecular colloidal impurities and unpleasant odor precursors, and exhibits good solubility and storage stability in food systems. Through graded extraction of petals and calyxes and micro-compounding, this extract significantly enhances the authenticity and complexity of the aroma, overcoming the problems of distorted aroma, insufficient freshness, and poor physical texture associated with traditional gardenia extracts.

[0018] The present invention also provides the application of the above-mentioned gardenia extract in edible flavorings, wherein the amount of gardenia extract added is 0.5-2% of the mass fraction of the edible flavoring.

[0019] Furthermore, the food flavorings include gardenia flavoring, green tea flavoring, or apple flavoring. Using gardenia extract in gardenia flavoring, with an addition amount of 0.8-1.5% of the gardenia flavoring's mass fraction, can make the flavoring aroma more delicate, the sweetness more mellow, and the palatability significantly improved. Using gardenia extract in green tea flavoring, with an addition amount of 0.5-0.8% of the green tea flavoring's mass fraction, can reduce the astringency of the tea and enhance the lingering fresh aroma. Using gardenia extract in apple flavoring, with an addition amount of 0.06-0.2% of the apple flavoring's mass fraction, can add a unique floral aroma and make the sweetness more layered.

[0020] When the gardenia flower extract of this invention is used in food flavorings, it can impart a more natural, full-bodied, and sweet floral aroma, enhancing the freshness and texture of the flavoring. This extract is suitable for various food flavoring systems and has broad application prospects and commercial value.

[0021] The beneficial effects of this invention are as follows: 1) This invention employs liquid nitrogen freezing technology to preserve freshness, using low-temperature extraction and membrane separation concentration at temperatures below 35°C throughout the process. This avoids the damage to aroma components caused by traditional heat concentration or distillation, significantly improving the dissolution rate of gardenia aroma substances. By combining the aromas of gardenia petals and calyxes, the natural fragrance of the entire gardenia flower is restored to the greatest extent possible. The resulting extract has a realistic aroma with strong layers, possessing the characteristic fresh, full-bodied, and sweet aroma of gardenia.

[0022] 2) This invention extracts petals and sepals separately and uses a specific membrane separation permeation and component retention compounding strategy to achieve graded recovery and recombination of aroma components, which significantly improves the aroma coordination, stability and fragrance retention of the extract.

[0023] 3) This invention significantly enhances the freshness and texture of the extract by adding trace amounts of calyx extract, thereby achieving high-value utilization of by-products and avoiding resource waste.

[0024] 4) This invention effectively removes large molecules such as polysaccharides, proteins, and colloids that cause precipitation through the combined action of microfiltration and ultrafiltration. The nanofiltration concentration process is carried out at low temperature, further avoiding component polymerization or deterioration caused by heating concentration. The resulting extract can be stored for a long time and used in beverage systems, remaining clear and transparent, without precipitation or flocculent matter, significantly improving the product's shelf stability and application suitability.

[0025] 5) This invention employs ultrasonic-assisted extraction, significantly improving extraction efficiency and reducing solvent consumption. Membrane separation technology achieves physical separation and concentration at room temperature, eliminating the need for high-temperature evaporation and resulting in significantly lower energy consumption compared to traditional vacuum distillation. The entire process does not use toxic or harmful organic solvents, leaving no harmful solvent residues, thus meeting the development requirements of clean production and natural food additives, and possessing high industrial application value.

[0026] 6) The gardenia extract prepared by this invention can be directly applied to various edible flavorings such as gardenia, green tea, and apple, significantly improving the overall aroma quality and palatability of the flavorings. It has a wide range of applications and good prospects for industrialization. Detailed Implementation

[0027] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0028] Example 1 This embodiment provides a method for preparing gardenia flower extract, including the following steps: S1. Pretreatment of raw materials by freezing and locking freshness with liquid nitrogen: Select fresh gardenia flowers, remove impurities and flower stems, and retain the calyx; place the treated gardenia flowers and calyxes in two stainless steel containers respectively, add liquid nitrogen to 0.5cm above the material, and treat in a non-sealed container for 5 minutes. S2. Pre-soaking of raw materials: The pre-treated gardenia flowers and calyxes are placed into two extraction tanks, and the extraction solvent is added. They are soaked for 15 minutes. The extraction solvent is refrigerated at 15°C for 3 hours before use. S3. Initial ultrasonic-assisted extraction: At a temperature of 22℃, the gardenia flowers and calyxes soaked in step S2 were first ultrasonically extracted for 30 minutes, and after stopping the ultrasonic treatment, the soaking was maintained for 20 minutes; then ultrasonic treatment was performed for 15 minutes, and after stopping the ultrasonic treatment, the soaking was maintained for 20 minutes; finally, ultrasonic treatment was performed for 15 minutes. After the ultrasonic treatment was completed, the initial gardenia flower extract solution and the initial calyx extract solution were obtained by filtration. S4. Secondary ultrasonic-assisted extraction: At a temperature of 22℃, the gardenia flower material and calyx material in the tank after ultrasonic-assisted extraction in step S3 were ultrasonically extracted for 20 minutes respectively. After stopping the ultrasonic treatment, the material was kept soaked for 20 minutes. Then, the material was ultrasonically treated for 15 minutes. After stopping the ultrasonic treatment, the material was kept soaked for 20 minutes. Finally, the material was ultrasonically treated for 15 minutes. After the ultrasonic treatment was completed, the material was filtered to obtain the secondary gardenia flower extract solution and the secondary calyx extract solution respectively. S5. Cold storage treatment, coarse filtration and centrifugation: Mix the first and second gardenia flower extract solutions evenly to obtain gardenia flower extract; mix the first and second calyx extract solutions evenly to obtain calyx extract; refrigerate the gardenia flower extract and calyx extract at 15℃ for 30 min; coarsely filter the refrigerated gardenia flower extract and calyx extract through a 200-mesh filter to remove flower residue; then centrifuge the filtrates to obtain gardenia flower extract concentrate and calyx extract concentrate, respectively. S6. Membrane separation and purification: Gardenia flower extract and calyx extract are processed sequentially through a three-stage membrane system of microfiltration, ultrafiltration and nanofiltration. The microfiltration and ultrafiltration permeate from gardenia flower are partially retained, and the microfiltration and ultrafiltration permeate from calyx are partially retained for later use. S7. Preparation: The microfiltration permeate, ultrafiltration permeate, and nanofiltration retentate from gardenia flowers are mixed in a volume ratio of 1:2:1 to obtain gardenia flower preparation solution; the microfiltration permeate, ultrafiltration permeate, and nanofiltration retentate from calyx flowers are mixed in a volume ratio of 1:2:1 to obtain calyx preparation solution; the calyx preparation solution is added to the gardenia flower preparation solution to obtain gardenia flower extract, wherein the amount of calyx preparation solution added accounts for 0.001% of the mass fraction of gardenia flower extract.

[0029] Furthermore, in step S2, the extraction solvent is a food-grade ethanol-water mixture with a volume ratio of 7:3 and a material-liquid volume ratio of 1:20.

[0030] Furthermore, in step S6, the microfiltration uses a ceramic membrane or a tubular organic membrane with a pore size of 0.3 μm and an operating pressure of 0.2 MPa.

[0031] Furthermore, in step S6, the ultrafiltration uses a spiral wound organic membrane with a molecular weight cutoff of 10-20 kDa and an operating pressure of 0.5 MPa.

[0032] Furthermore, in step S6, the nanofiltration uses a solvent-resistant nanofiltration membrane with a molecular weight cutoff of 150-500 Da and an operating pressure of 2 MPa.

[0033] Furthermore, in step S7, the gardenia extract is pale yellow to pale yellow-green in color and has a fresh, full, and sweet gardenia aroma.

[0034] This embodiment also provides a gardenia extract, which is prepared by the above-described method for preparing a gardenia extract.

[0035] Comparative Example 1 Unlike Example 1, the amount of calyx preparation added in this comparative example is 0.0001% of the mass fraction of gardenia extract.

[0036] Comparative Example 2 Unlike Example 1, the amount of calyx preparation added in this comparative example is 0.01% of the mass fraction of gardenia extract.

[0037] Comparative Example 3 Unlike Example 1, the gardenia extract in this comparative example did not contain calyx extract.

[0038] Comparative Example 4 Unlike Example 1, the gardenia extract in this comparative example was obtained by a mixed extraction of petals and calyx. That is, the preparation method of the gardenia extract in this comparative example includes the following steps: S1. Pretreatment of raw materials by freezing and locking freshness with liquid nitrogen: Select fresh gardenia flowers, remove impurities and flower stems, and retain the calyx; place the treated gardenia flowers and calyx in the same stainless steel container, wherein the mass ratio of gardenia flowers to calyx is 23:1, add liquid nitrogen to 0.5cm above the material, and place in a non-sealed container for 5 minutes. S2. Pre-soaking of raw materials: Put the pre-treated gardenia flower-calyx mixture into the extraction tank, add the extraction solvent, and soak for 15 minutes. The extraction solvent is refrigerated at 15°C for 3 hours before use. S3. Initial ultrasonic-assisted extraction: At a temperature of 22℃, the gardenia flower-calyx mixture soaked in step S2 was first ultrasonically extracted for 30 min, and after stopping the ultrasonic treatment, the soaking was maintained for 20 min; then ultrasonic treatment was performed for 15 min, and after stopping the ultrasonic treatment, the soaking was maintained for 20 min; finally, ultrasonic treatment was performed for 15 min, and after the ultrasonic treatment was completed, the initial gardenia flower-calyx mixture extract solution was obtained by filtration. S4. Secondary ultrasonic-assisted extraction: At a temperature of 22℃, the gardenia-calyx mixture in the tank after ultrasonic-assisted extraction in step S3 was first ultrasonically extracted for 20 minutes. After stopping the ultrasonic treatment, it was kept soaking for 20 minutes. Then, it was ultrasonically treated for 15 minutes. After stopping the ultrasonic treatment, it was kept soaking for 20 minutes. Finally, it was ultrasonically treated for 15 minutes. After the ultrasonic treatment was completed, it was filtered to obtain the secondary gardenia-calyx mixture extract solution. S5. Cold storage treatment and coarse filtration and centrifugation: Mix the first gardenia flower-calyx mixed extract solution and the second gardenia flower-calyx mixed extract solution evenly to obtain the gardenia flower-calyx mixed extract stock solution; S6. Membrane separation and purification: The gardenia flower-calyx mixed extract is processed sequentially through a three-stage membrane system of microfiltration, ultrafiltration and nanofiltration. The permeate from microfiltration and ultrafiltration is partially retained for later use. S7. Preparation: The microfiltration permeate, ultrafiltration permeate, and nanofiltration retentate are mixed in a volume ratio of 1:2:1 to obtain a gardenia-calyx mixed preparation solution, wherein the amount of gardenia-calyx mixed preparation solution added accounts for 0.001% of the mass fraction of gardenia extract.

[0039] Performance Test 1 Fifteen experienced fragrance tasters were selected and, in a professional fragrance tasting room, used tasting sticks dipped into gardenia extract prepared in Example 1 and Comparative Examples 1-3 to a height of 10 mm. The extracts were then smelled from 10-15 mm in front of the nose. The tasters evaluated and scored the extracts based on seven aspects: aroma characteristics, mouthfeel characteristics, fresh aroma, floral aroma, sweet aroma, freshness, and physical texture (out of 10). The scores were the average of the remaining scores after removing the highest and lowest scores. The results are shown in Table 1 below: Table 1

[0040] As shown in Table 1, the amount of calyx extract added in Comparative Example 1 was 0.0001% of the mass fraction of gardenia extract, which is lower than the range of 0.0008-0.0012% specified in this invention. Although its aroma characteristics (9.2 points), taste characteristics (9.2 points), and physical texture (9.4 points) remained at a high level, its freshness (8.5 points) and green aroma (4.5 points) were significantly lower than those in Example 1 (8.8 points and 6 points, respectively), indicating that insufficient calyx extract could not effectively enhance its freshness and balance the green aroma. In Comparative Example 2, the amount of calyx extract added was increased to 0.01%, which is far higher than the range specified in this invention. Its aroma characteristics (8.2 points), taste characteristics (7.5 points), sweet aroma (7.9 points), and physical texture (8 points) were all significantly lower than those in Example 1, especially the excessively high green aroma (8 points), which led to a decrease in overall aroma harmony and a poorer palatability. This indicates that excessive addition of calyx extract has a negative effect, masking the delicate floral fragrance of the petals and giving the extract an overly astringent taste, which is detrimental to its application in food flavorings. Comparative Example 3, a pure calyx extract (without added petal extract), performed poorly in terms of aroma and taste. While its floral aroma (8 points) was acceptable, its aroma characteristics (9 points) and taste characteristics (9 points) were still lower than Example 1, and its green aroma (3.8 points) was significantly lower, as were its freshness (7.8 points) and texture (9.2 points). This suggests that calyx extract is not suitable for use alone as a flavoring ingredient; direct use in food flavorings leads to a monotonous aroma, lack of complexity, and reduced palatability. However, when added in trace amounts to petal extract, calyx extract effectively compensates for the deficiencies of petal extract in terms of freshness and texture, resulting in an overall improvement in aroma. Comparative Example 4 combined the extraction of petals and calyxes. Due to the difficulty in precisely controlling the relative proportion of calyxes in the mixed system, the overall aroma harmony of the product decreased. Its aroma characteristics (7 points), taste characteristics (6.5 points), floral aroma (7 points), and physical characteristics (7.2 points) were all significantly lower than in Example 1, while the green aroma (9 points) was too high, resulting in an overly strong green aroma, a lack of prominent floral fragrance, and an overall unpleasant aroma. This indicates that the aroma components of petals and calyxes interfere with each other during extraction, failing to achieve the synergistic effect obtained in Example 1 through separate extraction and trace-level blending.

[0041] It is evident that only when calyx extract is added in extremely small amounts can it produce a synergistic effect with petal extract, significantly enhancing the freshness and texture of gardenia extract without compromising the overall aroma harmony due to an overly strong green fragrance. This is a key technical means to obtain high-quality gardenia extract.

[0042] Comparative Example 5 Unlike Example 1, the gardenia flower preparation solution in this comparative example only contains microfiltration permeate, that is, the gardenia flower preparation solution is microfiltration permeate.

[0043] Comparative Example 6 Unlike Example 1, the gardenia flower preparation solution in this comparative example only contains ultrafiltration permeate, that is, the gardenia flower preparation solution is an ultrafiltration permeate.

[0044] Comparative Example 7 Unlike Example 1, the gardenia flower preparation in this comparative example only contains nanofiltration cut-off solution, that is, the gardenia flower preparation is a nanofiltration cut-off solution.

[0045] Comparative Example 8 Unlike Example 1, the gardenia flower preparation solution in this comparative example is prepared by mixing microfiltration permeate and ultrafiltration permeate from gardenia flowers at a volume ratio of 1:1.

[0046] Comparative Example 9 Unlike Example 1, the gardenia flower preparation solution in this comparative example is prepared by mixing ultrafiltration permeate and nanofiltration retentate from gardenia flowers at a volume ratio of 1:1.

[0047] Comparative Example 10 Unlike Example 1, the gardenia flower preparation solution in this comparative example is a mixture of microfiltration permeate, ultrafiltration permeate, and nanofiltration retentate derived from gardenia flowers in a volume ratio of 1:1:1.

[0048] Performance Test 2 Fifteen experienced perfumers were selected to use a professional perfumery evaluation room to apply perfume strips containing gardenia extract prepared in Example 1 and Comparative Examples 5-10 to a height of 10 mm. The perfumes were then smelled from a distance of 10-15 mm in front of the nose. The perfumes were evaluated and scored based on five aspects: aroma intensity, harmony, comfort, longevity, and stability (20 points per aspect, 100 points total). The scores are the average of the remaining scores after removing the highest and lowest scores. The results are shown in Table 2 below. Table 2

[0049] As shown in Table 2, the gardenia extract prepared in Example 1 achieved the highest comprehensive score of 90 points in terms of aroma intensity, harmony, comfort, longevity, and stability, significantly outperforming all comparative examples. Comparative Example 5, using only the microfiltration permeate, showed high aroma intensity (18 points), but poor harmony (13 points) and stability (9 points), indicating that a single membrane component cannot achieve aroma balance and long-term stability. Comparative Example 6, using only the ultrafiltration permeate, had unsatisfactory aroma intensity and longevity. Comparative Example 7, using only the nanofiltration cut-off solution, had the lowest aroma intensity (9.5 points) and poor longevity (12 points), indicating that while the nanofiltration cut-off solution enriched some aroma components, it lacked the coordination of low molecular weight aroma substances. Comparative Examples 8 and 9 used blends of two membrane components, with overall scores of 69.5 and 69 respectively, still lower than Example 1. This indicates that a 1:2:1 ratio of the three membrane components (microfiltration permeate, ultrafiltration permeate, and nanofiltration retentate) is key to achieving harmonious aroma, moderate intensity, long-lasting fragrance, and excellent stability. Comparative Example 10, although using a blend of three components, had a volume ratio of 1:1:1, and achieved an overall score of 81.5, still lower than Example 1, further demonstrating the synergistic optimization effect of the volume ratio range defined in this invention.

[0050] Application Example 1 This application example provides an example of the use of gardenia extract in gardenia fragrance. Specifically, the amount of gardenia extract prepared in Example 1 added is 1.2% of the mass fraction of gardenia fragrance. Aroma evaluations were performed on gardenia fragrance with and without gardenia extract, and the results are shown in Table 3. Table 3

[0051] As shown in Table 3, the gardenia fragrance with the gardenia extract prepared in Example 1 of this invention scored 8.6 points in aroma and 9.0 points in taste, which are 1.1 and 2.0 points higher than the gardenia fragrance without the gardenia extract (7.5 and 7.0 points, respectively). This indicates that the addition of the gardenia extract of this invention makes the overall aroma of the gardenia fragrance fuller, more delicate, and sweeter, resulting in significantly improved palatability in products, allowing consumers to experience the true taste of gardenia more comfortably and naturally. In contrast, the gardenia fragrance without the gardenia extract has a thinner aroma, insufficient sweetness, and a certain chemical and irritating taste, with poor overall harmony. Therefore, the gardenia extract of this invention can effectively modify and enhance the aroma quality of gardenia fragrance, giving it a more natural and elegant floral fragrance, significantly improving its taste performance in food systems, and possessing outstanding application value.

[0052] Application Example 2 This application example provides an example of the use of gardenia extract in green tea flavoring. Specifically, the amount of gardenia extract prepared in Example 1 added is 0.6% of the mass fraction of the green tea flavoring. Aroma evaluations were performed on the green tea flavoring with and without gardenia extract, and the results are shown in Table 4. Table 4

[0053] As shown in Table 4, the green tea flavoring with the gardenia extract prepared in Example 1 of this invention scored 9.2 points in aroma and 9.5 points in taste, which are 1.2 and 1.7 points higher than the green tea flavoring without gardenia extract (8.0 and 7.8 points, respectively). This indicates that after adding the gardenia extract of this invention, the overall floral and sweet aroma of the green tea flavoring is more memorable. When applied to the product, this manifests as a significant reduction in astringency and a more lingering and pleasant fresh aroma. The green tea flavoring without gardenia extract has a relatively simple aroma, a heavier astringency, a shorter fresh aroma, and lacks complexity and aftertaste. The floral and sweet components in the gardenia extract of this invention can effectively neutralize the astringent substances in the green tea flavoring, while complementing the fresh aroma in the tea fragrance, making the overall aroma more rounded and harmonious, and the taste more mellow and comfortable. Therefore, the gardenia extract of the present invention can not only enhance the recognizability of floral and sweet aromas in green tea flavoring, but also significantly improve the astringency of tea and enhance the extension of the green aroma, thus having outstanding application value.

[0054] Application Example 3 This application example provides an example of the use of gardenia extract in apple flavoring. Specifically, the amount of gardenia extract prepared in Example 1 added is 0.6% of the apple flavoring by mass. Aroma evaluations were performed on apple flavoring with and without gardenia extract, and the results are shown in Table 5. Table 5

[0055] As shown in Table 5, the apple flavoring with the gardenia extract prepared in Example 1 of this invention achieved an aroma score of 9.0 and a taste score of 9.2, which are 0.5 and 0.6 points higher than the apple flavoring without gardenia extract (8.5 and 8.6 points, respectively). This indicates that the addition of the gardenia extract of this invention gives the apple flavoring a unique floral aroma and a more layered sweetness. When applied to products, it manifests as a fruity sweetness enveloped by a subtle floral aroma, resulting in a more pleasant and richer overall taste experience. The apple flavoring without gardenia extract has a relatively simple aroma, a more direct and flat sweetness, and lacks aftertaste and layered variations. The sweet floral components in the gardenia extract of this invention can form a good synergistic effect with the fruity sweet components in the apple flavoring, transforming the sweetness from a single fruity sweetness to a complex sweetness interwoven with fruity and floral sweetness, resulting in a more three-dimensional and delicate aroma. Meanwhile, the subtle floral aroma of gardenia extract effectively enhances the overall elegance of the fragrance, allowing consumers to experience a more natural and comfortable taste. Therefore, the gardenia extract of this invention not only adds a unique floral aroma to apple flavoring but also significantly improves the layers of sweetness and overall sensory pleasure, demonstrating outstanding application value.

[0056] The specific embodiments described above are further illustrations of the technical solution and beneficial effects of the present invention, and are not intended to limit the implementation methods. For those skilled in the art, any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A method for preparing gardenia flower extract, characterized in that: Includes the following steps: S1. Pretreatment of raw materials by freezing and locking freshness with liquid nitrogen: Select fresh gardenia flowers, remove impurities and flower stems, and retain the calyx; place the treated gardenia flowers and calyxes in two stainless steel containers respectively, add liquid nitrogen to 0.1-1cm above the material, and place them in a non-sealed container for 2-8 minutes. S2. Pre-soaking of raw materials: Place the pre-treated gardenia flowers and calyxes into two extraction tanks, add extraction solvent, and soak for 10-20 minutes. The extraction solvent should be refrigerated at 10-20℃ for 2-4 hours before use. S3. Initial ultrasonic-assisted extraction: At a temperature of 15℃-28℃, the gardenia flowers and calyxes soaked in step S2 were subjected to repeated ultrasonic extraction 2-4 times. Each ultrasonic treatment lasted 15-30 minutes, and the ultrasonic treatment was stopped and the soaking was maintained for 15-25 minutes until the last ultrasonic treatment was completed. After filtration, the initial gardenia flower extract solution and the initial calyx extract solution were obtained respectively. S4. Secondary ultrasonic-assisted extraction: At a temperature of 15℃-28℃, the gardenia flower material and calyx material in the tank after ultrasonic-assisted extraction in step S3 are subjected to repeated ultrasonic extraction 2-4 times. Each ultrasonic treatment lasts for 15-20 minutes. After each ultrasonic treatment, the ultrasonic treatment is stopped and the soaking is maintained for 15-25 minutes until the last ultrasonic treatment is completed. After filtration, secondary gardenia flower extract solution and secondary calyx extract solution are obtained. S5. Cold storage treatment, coarse filtration and centrifugation: Mix the first and second gardenia flower extract solutions evenly to obtain gardenia flower extract; mix the first and second calyx extract solutions evenly to obtain calyx extract; refrigerate the gardenia flower extract and calyx extract at 10-20℃ for 25-35 minutes; filter the refrigerated gardenia flower extract and calyx extract separately through a 180-220 mesh filter to remove flower residue; then centrifuge the filtrate to obtain gardenia flower extract concentrate and calyx extract concentrate, respectively. S6. Membrane separation and purification: Gardenia flower extract and calyx extract are processed sequentially through a three-stage membrane system of microfiltration, ultrafiltration and nanofiltration. The microfiltration and ultrafiltration permeate from gardenia flower are partially retained, and the microfiltration and ultrafiltration permeate from calyx are partially retained for later use. S7. Preparation: Mix the microfiltration permeate, ultrafiltration permeate, and nanofiltration retentate from gardenia flowers at a volume ratio of 1:(1.5-2.5):1 to obtain gardenia flower preparation solution; mix the microfiltration permeate, ultrafiltration permeate, and nanofiltration retentate from calyx flowers at a volume ratio of 1:(1.5-2.5):1 to obtain calyx preparation solution; add the calyx preparation solution to the gardenia flower preparation solution to obtain gardenia flower extract, wherein the amount of calyx preparation solution added accounts for 0.0008-0.0012% of the mass fraction of gardenia flower extract.

2. The method for preparing gardenia extract according to claim 1, characterized in that: In step S2, the extraction solvent is a food-grade ethanol-water mixture with a volume ratio of 6-8:3 and a material-liquid volume ratio of 1:18-22.

3. The method for preparing gardenia extract according to claim 1, characterized in that: In step S3, at a temperature of 15-28℃, the gardenia flowers and calyxes soaked in step S2 are first subjected to ultrasonic extraction for 25-35 min, respectively. After stopping the ultrasonic treatment, the soaking is maintained for 15-25 min. Then, the ultrasonic treatment is performed for 10-20 min, and the ultrasonic treatment is stopped while maintaining the soaking for 15-25 min. Finally, the ultrasonic treatment is performed for 10-20 min. After the ultrasonic treatment is completed, the initial gardenia flower extract solution and the initial calyx extract solution are obtained by filtration.

4. The method for preparing gardenia extract according to claim 1, characterized in that: In step S4, the gardenia flower material and calyx material in the tank after ultrasonic-assisted extraction in step S3 are first ultrasonically extracted for 15-25 minutes, respectively. After stopping the ultrasonic treatment, the material is kept soaked for 15-25 minutes. Then, the material is ultrasonically treated for 10-20 minutes, and the ultrasonic treatment is stopped while keeping the material soaked for 15-25 minutes. Finally, the material is ultrasonically treated for 10-20 minutes. After the ultrasonic treatment is completed, the material is filtered to obtain the secondary gardenia flower extract solution and the secondary calyx extract solution.

5. The method for preparing gardenia extract according to claim 1, characterized in that: In step S6, the microfiltration uses a ceramic membrane or tubular organic membrane with a pore size of 0.1-0.5 μm and an operating pressure of 0.1-0.3 MPa.

6. The method for preparing gardenia extract according to claim 1, characterized in that: In step S6, the ultrafiltration uses a spiral wound organic membrane with a molecular weight cutoff of 5-20 kDa and an operating pressure of 0.3-0.8 MPa.

7. The method for preparing gardenia extract according to claim 1, characterized in that: In step S6, the nanofiltration uses a solvent-resistant nanofiltration membrane with a molecular weight cutoff of 150-500 Da and an operating pressure of 1.5-2.5 MPa.

8. The method for preparing gardenia extract according to claim 2, characterized in that: In step S7, the gardenia extract is pale yellow to pale yellow-green in color and has a fresh, full, and sweet gardenia aroma.

9. A gardenia extract, characterized in that: It is prepared by the method for preparing gardenia extract according to any one of claims 1-8.

10. The application of gardenia extract in edible flavoring according to claim 9, characterized in that: The food flavorings include gardenia flavoring, green tea flavoring, or apple flavoring.

Images