Method for processing gardenia by adopting vacuum low-temperature freeze-drying technology, dried gardenia and application

Abstract

The invention discloses a method for processing gardenia by adopting a vacuum low-temperature freeze-drying technology, a dried gardenia product and application, and belongs to the technical field of food processing. The method comprises the following steps: picking fresh cape jasmine flowers which bloom initially, removing impurities such as pedicels, sepals and leaves, and cleaning for later use; withering, draining, dishing, and carrying out low-temperature quick-freezing; transferring the quick-frozen gardenia to a freeze dryer, and performing freeze drying; and packaging. The invention also discloses the dried gardenia product prepared by the method, and application of the dried gardenia product in preparation of tea drink raw materials, flower substitutional tea, aromatherapy products and handicrafts. The dried gardenia processed by the method can retain more than 90% of original forms and active components, is good in rehydration effect, sweet, mellow and full in taste and resistant to storage and transportation, can be directly used as a novel tea drink raw material, can be directly brewed with flower substitutional tea, can be applied to application scenes such as aromatherapy products and handicrafts, and is suitable for commercial production or family small-scale production.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a method for processing gardenia flowers using vacuum low-temperature freeze-drying technology, dried gardenia flowers, and their applications. Background Technology

[0002] Gardenia, belonging to the genus Gardenia in the family Rubiaceae, is widely distributed in many regions of my country, including East China, South China, North China, and Southwest China. It is a valuable floral resource with significant economic, cultural, and medicinal value. Beyond its ornamental appeal, gardenia is also frequently used in food processing and traditional Chinese medicine preparations. Its flowers and fruits are rich in geniposide, chlorogenic acid, and volatile oils, possessing properties that clear heat and dampness, cool the blood, and detoxify. It has wide applications in both traditional Chinese medicine and modern functional foods.

[0003] Because gardenia petals have a high water content and delicate tissue, they are highly susceptible to enzymatic browning, microbial contamination, and the volatilization of aromatic substances after harvesting, leading to rapid deterioration in quality and significant losses during storage and transportation. This severely limits the commercial development and cross-regional distribution of gardenias. To extend shelf life, drying is the commonly used processing method for gardenias, including natural sun drying and hot air drying. However, these traditional drying processes have significant drawbacks: prolonged high-temperature processing easily causes a large loss of volatile aromatic components, resulting in a weak floral fragrance; heat-sensitive substances such as gardenia yellow pigment degrade significantly, leading to a dull color and widespread browning in the finished product; the petal structure collapses, rehydration is poor, the taste is bland, and the overall quality is low.

[0004] Existing drying technologies fail to effectively balance drying efficiency and quality preservation, impacting not only the sensory properties and commercial value of dried gardenia flowers but also reducing consumer acceptance and repurchase rates. This hinders the high-value development of gardenia resources and the sustainable development of the industry. Therefore, a gardenia drying process that can balance drying rate and quality stability is urgently needed.

[0005] Therefore, providing a drying method for gardenia flowers that can preserve the original morphology and active ingredients of gardenia flowers, with good rehydration effect, sweet and mellow taste, and good storage and transportation properties has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the problems of weak aroma, browning, deteriorated taste, and poor shape retention in existing dried gardenia flower products caused by traditional drying methods, this invention provides a method for processing gardenia flowers using vacuum low-temperature freeze-drying technology. Gardenia flowers processed using this method retain over 90% of their original shape and active ingredients, exhibit excellent rehydration properties, a sweet and full-bodied taste, and good storage and transportation resistance. They can be directly used as a raw material for new-style teas, as a substitute for flower teas, in aromatherapy products, and in handicrafts, among other applications. Suitable for commercial production or small-scale home production, this method has significant application and promotional value.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The first aspect of this invention discloses a method for processing gardenia flowers using vacuum low-temperature freeze-drying technology, the method comprising the following steps:

[0009] (1) Preparation of fresh gardenia flowers: Pick fresh gardenia flowers that have just opened, remove the flower stems, sepals, leaves and other debris, and wash them for later use;

[0010] (2) Draining: Wither the fresh flowers to drain off the water attached to the surface, then put them on a plate for quick freezing at low temperature;

[0011] (3) Vacuum freeze drying: Transfer the quick-frozen gardenia flowers to a freeze dryer for freeze drying;

[0012] (4) Packaging: After drying, immediately place the flowers into a sealed bag or nitrogen-filled packaging.

[0013] In some embodiments of the present invention, the gardenia is a variety of gardenia with a milky fragrance.

[0014] In some embodiments of the present invention, all the work in step (1) and the withering, draining and traying work in step (2) need to be completed within 6 hours.

[0015] In some embodiments of the present invention, in step (3), low-temperature freeze drying is performed by heating with a partition.

[0016] In some embodiments of the present invention, in step (3), the gardenia flowers that have been quick-frozen at low temperature are transferred to a freeze dryer, freeze-drying parameters are set, and freeze-drying is performed.

[0017] Preferably, the temperature control parameters are as follows: within 15 hours, the temperature is raised to 4-6°C and maintained for 3-5 hours; the temperature is raised to 9-11°C and maintained for 3-5 hours; the temperature is raised to 14-16°C and maintained for 3-5 hours; and then the temperature is lowered to -6--4°C and maintained for 0.5-2 hours, with the cold trap temperature being -40--30°C.

[0018] In some embodiments of the present invention, the temperature control parameters are as follows: within 15 hours, the temperature is increased to 5°C and maintained for 5 hours; the temperature is increased by 10°C and maintained for 5 hours; the temperature is increased by 15°C and maintained for 5 hours; the temperature is decreased to -5°C and maintained for 2 hours; and the cold trap temperature is -35°C.

[0019] In some embodiments of the present invention, the temperature control parameters are as follows: within 15 hours, the temperature is increased to 5°C and maintained for 5 hours; the temperature is increased by 10°C and maintained for 5 hours; the temperature is increased by 15°C and maintained for 4 hours; the temperature is decreased to -5°C and maintained for 1 hour; and the cold trap temperature is -35°C.

[0020] In some embodiments of the present invention, the temperature control parameters are as follows: within 15 hours, the temperature is increased to 5°C and maintained for 4 hours; the temperature is increased to 10°C and maintained for 4 hours; the temperature is increased to 15°C and maintained for 4 hours; the temperature is decreased to -5°C and maintained for 1 hour; and the cold trap temperature is -35°C.

[0021] In some embodiments of the present invention, the vacuum degree during freeze drying is controlled to be -40 to -30 kPa, preferably -35 kPa.

[0022] The second aspect of this invention also discloses dried gardenia flowers processed using the aforementioned vacuum low-temperature freeze-drying technology.

[0023] In some embodiments of the present invention, the dried gardenia flowers have a moisture content of less than 5%.

[0024] The third aspect of this invention discloses the application of the above-mentioned dried gardenia flowers in the preparation of tea raw materials, flower substitute teas, aromatherapy products, and handicrafts.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention is scientifically designed and ingeniously conceived. Gardenia flower products prepared through vacuum low-temperature freeze-drying have diverse applications. They can be used directly as raw materials for new-style tea drinks, as flower substitutes for tea, and also in aromatherapy products and craft decorations. They are suitable for both commercial-scale production and small-scale home production, demonstrating broad application and promotional value.

[0027] The dried gardenia flowers prepared using the method of this invention are of excellent quality. The preparation process is based on the original water content characteristics of fresh flowers and employs a reasonable gradient cooling and heating procedure, which is not only energy-efficient but also achieves high-quality drying results in a short time. The resulting dried gardenia flowers have good rehydration properties and release a natural milky aroma with a unique flavor.

[0028] Furthermore, the preparation method disclosed in this invention is highly operable, has a clear process, and is easy to standardize and industrialize. Overall, it has good practicality and market prospects, and is especially suitable for the development and promotion of flower tea products. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0030] Example 1

[0031] This embodiment discloses a method for processing gardenia flowers using vacuum low-temperature freeze-drying technology, as detailed below:

[0032] (1) Preparation of fresh gardenia flowers: Pick fresh gardenia flowers that have just opened, remove the flower stems, sepals, leaves and other debris, and wash them for later use; the gardenia flowers in this embodiment are the gardenia varieties with a milky fragrance.

[0033] (2) Draining: Wither the fresh flowers to drain off the water attached to the surface, then put them on a plate for quick freezing at low temperature;

[0034] In steps (1) and (2), from picking fresh gardenia flowers to withering, draining, and plating, the entire process is completed within 6 hours.

[0035] (3) Vacuum freeze drying: The quick-frozen gardenia flowers were transferred to a freeze dryer, the freeze drying parameters were set, and the low-temperature freeze drying with a vacuum degree of -35 kPa was carried out by partition heating. The temperature control parameters were: within 15 hours, the temperature was raised to 5℃ and maintained for 5 hours, the temperature was raised to 10℃ and maintained for 5 hours, the temperature was raised to 15℃ and maintained for 5 hours, the temperature was lowered to -5℃ and maintained for 2 hours, and the cold trap temperature was -35℃.

[0036] This embodiment yields gardenia dried flower products with a moisture content of less than 4%.

[0037] (4) Packaging: After drying, immediately put the flowers into a sealed bag for packaging.

[0038] The freeze-drying parameters in this embodiment can be adjusted as needed based on actual conditions.

[0039] Example 2

[0040] This embodiment discloses a method for processing gardenia flowers using vacuum low-temperature freeze-drying technology, as detailed below:

[0041] (1) Preparation of fresh gardenia flowers: Pick fresh gardenia flowers that have just opened, remove the flower stems, sepals, leaves and other debris, and wash them for later use; the gardenia flowers in this embodiment are the gardenia varieties with a milky fragrance.

[0042] (2) Draining: Wither the fresh flowers to drain off the water attached to the surface, then put them on a plate for quick freezing at low temperature;

[0043] In steps (1) and (2), from picking fresh gardenia flowers to withering, draining, and plating, the entire process is completed within 6 hours.

[0044] (3) Vacuum freeze drying: The quick-frozen gardenia flowers were transferred to a freeze dryer, the freeze drying parameters were set, and the low-temperature freeze drying with a vacuum degree of -35 kPa was carried out by partition heating. The temperature control parameters were: within 15 hours, the temperature was raised to 5℃ and maintained for 5 hours, the temperature was raised to 10℃ and maintained for 5 hours, the temperature was raised to 15℃ and maintained for 4 hours, the temperature was lowered to -5℃ and maintained for 1 hour, and the cold trap temperature was -35℃.

[0045] This embodiment yields gardenia dried flower products with a moisture content of less than 4.2%.

[0046] (4) Packaging: After drying, immediately put the flowers into a sealed bag for packaging.

[0047] The freeze-drying parameters in this embodiment can be adjusted as needed based on actual conditions.

[0048] Example 3

[0049] This embodiment discloses a method for processing gardenia flowers using vacuum low-temperature freeze-drying technology, as detailed below:

[0050] (1) Preparation of fresh gardenia flowers: Pick fresh gardenia flowers that have just opened, remove the flower stems, sepals, leaves and other debris, and wash them for later use; the gardenia flowers in this embodiment are the gardenia varieties with a milky fragrance.

[0051] (2) Draining: Wither the fresh flowers to drain off the water attached to the surface, then put them on a plate for quick freezing at low temperature;

[0052] In steps (1) and (2), from picking fresh gardenia flowers to withering, draining, and plating, the entire process is completed within 6 hours.

[0053] (3) Vacuum freeze drying: The quick-frozen gardenia flowers were transferred to a freeze dryer, the freeze drying parameters were set, and the low-temperature freeze drying with a vacuum degree of -35 kPa was carried out by partition heating. The temperature control parameters were: within 15 hours, the temperature was raised to 5℃ and maintained for 4 hours, the temperature was raised to 10℃ and maintained for 4 hours, the temperature was raised to 15℃ and maintained for 4 hours, the temperature was lowered to -5℃ and maintained for 1 hour, and the cold trap temperature was -35℃.

[0054] This embodiment yields gardenia dried flower products with a moisture content of less than 4.5%.

[0055] (4) Packaging: After drying, immediately pack the flowers with nitrogen gas.

[0056] The freeze-drying parameters in this embodiment can be adjusted as needed based on actual conditions.

[0057] The sensory quality of the dried gardenia flowers prepared in Examples 1-3 was evaluated, and the results are shown in Table 1.

[0058] Table 1. Sensory quality evaluation of gardenia-based substitute teas in three examples.

[0059] Product Name shape soup color aroma taste leaf base Overall Score Example 1 milky white Bright The scent is distinctly milky, long-lasting, and has a subtle hint of gardenia. Sweet and mellow White, in clusters 96 Example 2 milky white Bright The milky aroma is pronounced, long-lasting, and slightly milky. Sweet and mellow White, in clusters 95 Example 3 milky white Bright The scent is distinctly gardenia with a hint of milk. Sweet and mellow White, in clusters 93

[0060] Finally, it should be noted that the above embodiments are merely preferred embodiments of the present invention used to illustrate the technical solutions of the present invention, and are not intended to limit the invention, nor are they intended to limit the scope of the patent. Any modifications or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but which still solve the same technical problem as the present invention, should be included within the scope of protection of the present invention. In addition, the direct or indirect application of the technical solutions of the present invention to other related technical fields are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for processing gardenia flowers using vacuum low-temperature freeze-drying technology, characterized in that, Includes the following steps: (1) Preparation of fresh gardenia flowers: Pick fresh gardenia flowers that have just opened, remove the flower stems, sepals, leaves and other debris, and wash them for later use; (2) Draining: Wither the fresh flowers to drain off the water attached to the surface, then put them on a plate for quick freezing at low temperature; (3) Vacuum freeze drying: Transfer the quick-frozen gardenia flowers to a freeze dryer for freeze drying; (4) Packaging: After drying, immediately place the flowers into a sealed bag or nitrogen-filled packaging.

2. The method for processing gardenia flowers using vacuum low-temperature freeze-drying technology according to claim 1, characterized in that, The gardenia mentioned is a variety with a milky fragrance.

3. The method for processing gardenia flowers using vacuum low-temperature freeze-drying technology according to claim 1, characterized in that, All the work in step (1) and the withering, draining and plating work in step (2) need to be completed within 6 hours.

4. The method for processing gardenia flowers using vacuum low-temperature freeze-drying technology according to claim 1, characterized in that, In step (3), low-temperature freeze drying is performed using a partition heating method.

5. A method for processing gardenia flowers using vacuum low-temperature freeze-drying technology according to claim 1, characterized in that, In some embodiments of the present invention, in step (3), the gardenia flowers that have been quick-frozen at low temperature are transferred to a freeze dryer, freeze-drying parameters are set, and freeze-drying is performed. Preferably, the temperature control parameters are as follows: within 15 hours, the temperature is raised to 4-6°C and maintained for 3-5 hours; the temperature is raised to 9-11°C and maintained for 3-5 hours; the temperature is raised to 14-16°C and maintained for 3-5 hours; and then the temperature is lowered to -6--4°C and maintained for 0.5-2 hours, with the cold trap temperature being -40--30°C. More preferably, the temperature control parameters are: within 15 hours, the temperature is increased to 5°C and maintained for 5 hours; the temperature is increased by 10°C and maintained for 5 hours; the temperature is increased by 15°C and maintained for 5 hours; the temperature is decreased to -5°C and maintained for 2 hours; and the cold trap temperature is -35°C. More preferably, the temperature control parameters are: within 15 hours, the temperature is increased to 5°C and maintained for 5 hours; the temperature is increased to 10°C and maintained for 5 hours; the temperature is increased to 15°C and maintained for 4 hours; the temperature is decreased to -5°C and maintained for 1 hour; and the cold trap temperature is -35°C. More preferably, the temperature control parameters are: within 15 hours, the temperature is increased to 5°C and maintained for 4 hours; the temperature is increased to 10°C and maintained for 4 hours; the temperature is increased to 15°C and maintained for 4 hours; the temperature is decreased to -5°C and maintained for 1 hour; and the cold trap temperature is -35°C.

6. A method for processing gardenia flowers using vacuum low-temperature freeze-drying technology according to claim 1, characterized in that, The vacuum level during freeze drying is controlled at -40 to -30 kPa, preferably -35 kPa.

7. A dried gardenia flower product, characterized in that, The gardenia was prepared by the method described in any one of claims 1-6, which uses vacuum low-temperature freeze-drying technology.

8. The dried gardenia flower product according to claim 7, characterized in that, The dried gardenia flowers have a moisture content of less than 5%.

9. The application of the dried gardenia flowers according to claim 7 or 8 in the preparation of tea raw materials, flower substitute teas, aromatherapy products, and handicrafts.