Preparation method of mashed lily

Abstract

The invention discloses a preparation method of mashed lily. The preparation method comprises the following steps: segmenting fresh lily bulbs, cleaning, blanching, protecting color, cooking and softening, grinding into thick liquid, sterilizing, cooling, and packaging in vacuum to obtain a finished product. In the cleaning link, a cleaning agent synergistic effect mode is selected through an ozone technology; according to the cleaning agent, functional auxiliaries are adopted, particularly stevioside and nisin cooperate with sodium citrate, sodium benzoate and ethyl alcohol to be combined, damage to the cleaning link in the processing process of the lily paste is effectively solved, and the prepared lily paste is good in anti-aging performance and long in follow-up storage life and has good commercial prospects.

Description

Technical Field

[0001] The present invention belongs to the field of food processing and relates to a method for preparing lily puree. Background Art

[0002] Lily (scientific name: Lilium brownii var. viridulum Baker) is a perennial herbaceous bulbous plant of the genus Lilium in the family Liliaceae. This plant is native to China and is widely distributed in the northern temperate regions of the Northern Hemisphere, such as eastern Asia, Europe, and North America. Its bulbs are rich in starch, edible, and also used medicinally. During the food processing process, lily scales are prone to deterioration, browning, and rotting, seriously affecting the taste and safety of the finished product.

[0003] During the processing of lily puree, problems such as deterioration, browning, and rotting of lily scales easily occur, which seriously affect the taste and safety of the lily puree finished product. The prior art CN106235215A prepares lily jelly through ultrasonic color protection of fresh lily scales with a mixed solution of sodium erythorbate / citric acid / sodium chloride after washing and then through deep food processing, enriching the variety of lily products and increasing the added value of lilies. CN114868912A discloses a method of adding water to lily scales to make a pulp, and after subjecting the obtained pulp to lipase enzymolysis, combining it with bean pods to prepare an expanded food. The corresponding lipase participates in the metabolism of lipid substances such as phospholipids in cell membranes, reducing the content of fatty acids in the finished product of large lilies and meeting the dietary needs of special populations. The browning of lilies is mainly caused by enzymatic browning. In actual production, it is necessary to reduce the content of antioxidant substances and phenolic compounds in lilies to avoid damage to the commercial value of its products. Summary of the Invention

[0004] In view of the defects of the prior art, the present invention discloses a processing technology for lily puree to maximize the retention of the nutritional components of the lily finished product; while extending its shelf life, effectively solving the browning problem existing in the processing of lily puree.

[0005] A processing technology for lily puree includes the following steps:

[0006] Fresh lily bulbs → Petaling → Washing → Blanching → Color protection → Cooking and softening → Pulping → Sterilization → Cooling → Vacuum packaging → Finished product.

[0007] Specifically, a method for preparing lily puree is as follows:

[0008] The fresh lily bulbs are separated into segments; 300 - 800 g of fresh lily scales are taken and soaked in 1000 - 2000 mL of water; 1 - 3 mg of ozone gas is continuously introduced into the above water for 1 - 3 min, 50 - 100 mL of a cleaning agent is added, and then shaken and mixed for 1 - 3 min. The fresh lily scales are taken out and air-dried for 0.5 - 2 h; then they are added to hot water at 80 - 100 °C and blanched for 5 - 10 min; taken out and placed in 500 - 1000 mL of 0.15 - 0.25% citric acid aqueous solution for color protection for 1 - 5 min; taken out and steamed and softened at 100 - 120 °C for 8 - 12 min, and then ground into pulp in a high-speed tissue grinder at 3000 - 8000 r / min for 1 - 3 min; sterilized at 90 - 120 °C for 10 - 20 min and cooled to room temperature; packed in a composite package at 80 - 150 g per package and vacuumized to obtain the lily paste.

[0009] Preferably, the preparation method of the cleaning agent is as follows: 5 - 100 mg of a functional auxiliary agent and 0.3 - 0.8 g of sodium citrate are taken and mixed and added to 50 - 100 mL of water, and stirred at 30 - 80 °C and 100 - 200 r / min for 5 - 15 min; then 0.1 - 0.5 g of sodium benzoate and 10 - 30 mL of ethanol are successively added, and stirred at 100 - 200 r / min for 8 - 10 min.

[0010] The functional auxiliary agent involved in the cleaning agent is any one of chitosan, sodium alginate, stevioside, span - 60, tween - 80, and nisin. Preferably, the functional auxiliary agent is a mixture of stevioside and nisin.

[0011] The present invention also discloses the above preparation method for lily paste, which is specifically as follows:

[0012] The fresh lily bulbs are separated into segments; 300 - 800 g of fresh lily scales are taken and soaked in 1000 - 2000 mL of water; 50 - 100 mL of a cleaning agent is added, and then shaken and mixed for 1 - 3 min. The fresh lily scales are taken out and air-dried for 0.5 - 2 h; then they are added to hot water at 80 - 100 °C and blanched for 5 - 10 min; taken out and placed in 500 - 1000 mL of 0.15 - 0.25% citric acid aqueous solution for color protection for 1 - 5 min; taken out and steamed and softened at 100 - 120 °C for 8 - 12 min, and then ground into pulp at 3000 - 8000 r / min for 1 - 3 min; sterilized at 90 - 120 °C for 10 - 20 min and cooled to room temperature; packed in a composite package at 80 - 150 g per package and vacuumized to obtain the lily paste.

[0013] The beneficial effects of the present invention:

[0014] 1. Compared with the prior art, through the intervention of ozone technology, the present invention can destroy the chemical structure of pesticide molecules and decompose them into harmless small molecule substances. For some pesticides containing easily oxidizable structures such as double bonds and benzene rings, ozone can degrade them through addition, oxidative bond cleavage and other reactions. Moreover, the reactive oxygen free radicals generated by the decomposition of ozone in water can also participate in the oxidation reaction, further improving the removal effect of pesticide residues.

[0015] 2. Compared with the prior art, the present invention adds a cleaning agent in the cleaning step. The functional additives added to this cleaning agent can form a protective film on the surface of lilies. This film can reduce the contact between oxygen and polyphenol oxidase and peroxidase in lily cells, thereby reducing their activity. Taking nisin, an antibacterial peptide, as an example, it can specifically bind to the active sites of polyphenol oxidase and peroxidase, changing the spatial conformation of the enzyme, so that the enzyme cannot normally bind to the substrate, thus directly inhibiting the catalytic activity of the enzyme.

[0016] 3. Compared with the prior art, the nisin involved in the present invention synergizes with other functional additives in the cleaning agent system containing other components, enhancing the chemical reactions between functional groups such as amino and carboxyl groups in nisin and specific groups in propiconazole, cyprodinil, and flutriafol, changing the chemical properties and physical states of pesticide residue molecules, making them more likely to fall off from the surface of lilies and dissolve in the cleaning solution, achieving the effect of removing pesticide residues. Description of the Drawings

[0017] Figure 1 It is a flow chart for the preparation of the finished lily paste. Detailed Embodiments

[0018] A method for preparing lily paste is as follows:

[0019] The fresh lily bulbs are separated into petals. 300 - 800 g of fresh lily scales are taken and added to 1000 - 2000 mL of water for soaking. At the same time, 1 - 3 mg of ozone gas is continuously introduced into the above water for 1 - 3 min. After adding 50 - 100 mL of the cleaning agent, it is oscillated and mixed for 1 - 3 min. The fresh lily scales are taken out and air-dried for 0.5 - 2 h; then they are added to hot water at 80 - 100 °C for blanching for 5 - 10 min; taken out and placed in 800 mL of 0.15 - 0.25% citric acid aqueous solution for color protection for 1 - 5 min; taken out and steamed and softened at 100 - 120 °C for 8 - 12 min, and then put into a high-speed tissue grinder at 3000 - 8000 r / min for grinding for 1 - 3 min; sterilized at 90 - 120 °C for 10 - 20 min and cooled to room temperature; packed into a composite package at 80 - 150 g per package and vacuumized to obtain the lily paste.

[0020] The preparation method of the above cleaning agent is specifically as follows:

[0021] The preparation method of the cleaning agent is as follows: Take 5 - 100 mg of functional auxiliary agent and 0.3 - 0.8 g of sodium citrate, mix and add them to 50 - 100 mL of water, stir at 30 - 80 °C and 100 - 200 r / min for 5 - 15 min; then continue to add 0.1 - 0.5 g of sodium benzoate and 10 - 30 mL of ethanol in sequence, and stir at 100 - 200 r / min for 8 - 10 min.

[0022] Nisin: It can specifically bind to the active sites of polyphenol oxidase and peroxidase, inhibit the enzyme activity, and reduce browning.

[0023] Stevioside: It has a preliminary dissolving and dispersing effect on hydrophilic stains; it may solubilize nisin and stabilize the cleaning agent formulation system; it inhibits the growth of surface microorganisms of lilies by virtue of its biocompatibility and antibacterial properties, indirectly stabilizing the enzyme activity; it collaborates with ozone free radicals to inhibit the enzyme activity and reduce the color change of lily puree.

[0024] Sodium citrate: Adjust the acidity and alkalinity of the cleaning agent, maintain the stability of the system, and help other components play their roles better.

[0025] Sodium benzoate: Inhibit the growth and reproduction of microorganisms and prevent lilies from deteriorating during processing and storage.

[0026] The parameters and sources of some substances in the examples are as follows:

[0027] Lily: The fresh lilies used in the examples of the present invention are produced in Qujing, Yunnan.

[0028] Example 1

[0029] A preparation method of lily puree is as follows:

[0030] Separate the fresh lily bulbs into petals; take 500 g of fresh lily scales, add them to 1500 mL of water and soak; continuously introduce 3 mg of ozone gas into the above water for 1 min; add 80 mL of the cleaning agent, then oscillate and mix for 1 min, take out the fresh lily scales and air-dry for 1 h; then add them to hot water at 90 °C and blanch for 6 min; take out and place them in 800 mL of 0.2% citric acid aqueous solution for color protection for 3 min; take out, cook and soften at 100 °C for 10 min, then put them into a high-speed tissue homogenizer at 5000 r / min and grind for 1 min; sterilize at 100 °C for 15 min, and cool at room temperature; pack 100 g per portion into a composite package and vacuumize to obtain the lily puree.

[0031] The preparation method of the cleaning agent is as follows: Take 0.01 g of chitosan and 0.5 g of sodium citrate, mix and add them to 100 mL of water, stir in a water bath at 50 °C and 200 r / min for 10 min; then continue to add 0.3 g of sodium benzoate and 20 mL of ethanol in sequence, and stir at 100 r / min for 8 min.

[0032] Example 2

[0033] A method for preparing lily puree is as follows:

[0034] Separate the fresh lily bulbs into petals, take 500 g of fresh lily scales and soak them in 1500 mL of water; continuously introduce 3 mg of ozone gas into the above water for 1 min; add 80 mL of cleaning agent and then oscillate and mix for 1 min, take out the fresh lily scales and air-dry them for 1 h; then add them to hot water at 90 °C and blanch for 6 min, take out and place them in 800 mL of 0.2% citric acid aqueous solution for color protection for 3 min; take out and carry out softening by steaming at 100 °C for 10 min, then put them into a high-speed tissue homogenizer at 5000 r / min and grind for 1 min; sterilize at 100 °C for 15 min and cool at room temperature; pack them into a composite package at 100 g per package and vacuumize to obtain the lily puree.

[0035] The preparation method of the cleaning agent is as follows: take 0.01 g of sodium alginate and 0.5 g of sodium citrate, mix and add 100 mL of water, stir at 50 °C in a water bath and 200 r / min for 10 min; then sequentially add 0.3 g of sodium benzoate and 20 mL of ethanol, and stir at 100 r / min for 8 min.

[0036] Example 3

[0037] A method for preparing lily puree is as follows:

[0038] Separate the fresh lily bulbs into petals, take 500 g of fresh lily scales and soak them in 1500 mL of water, continuously introduce 3 mg of ozone gas into the above water for 1 min; add 80 mL of cleaning agent and then oscillate and mix for 1 min, take out the fresh lily scales and air-dry them for 1 h; then add them to hot water at 90 °C and blanch for 6 min; take out and place them in 800 mL of 0.2% citric acid aqueous solution for color protection for 3 min; take out and carry out softening by steaming at 100 °C for 10 min, then put them into a high-speed tissue homogenizer at 5000 r / min and grind for 1 min; sterilize at 100 °C for 15 min and cool at room temperature; pack them into a composite package at 100 g per package and vacuumize; thus obtaining the lily puree.

[0039] The preparation method of the cleaning agent is as follows: take 0.01 g of stevioside and 0.5 g of sodium citrate, mix and add 100 mL of water, stir at 50 °C in a water bath and 200 r / min for 10 min; then add 0.3 g of sodium benzoate and 20 mL of ethanol, and stir at 100 r / min for 8 min.

[0040] Example 4

[0041] A method for preparing lily puree is as follows:

[0042] The fresh lily bulbs are separated into segments, and 500 g of fresh lily scales are taken and soaked in 1500 mL of water; 3 mg of ozone gas is continuously introduced into the above water for 1 min; after adding 80 mL of cleaning agent, it is oscillated and mixed for 1 min, and the fresh lily scales are taken out and air-dried for 1 h; then it is added to hot water at 90 °C for blanching for 6 min, taken out and placed in 800 mL of 0.2% citric acid aqueous solution for color protection for 3 min; taken out and steamed and softened at 100 °C for 10 min, then put into a high-speed tissue homogenizer at 5000 r / min for pulping for 1 min; sterilized at 100 °C for 15 min and cooled at room temperature; filled into a composite package at 100 g per portion and vacuumized to obtain the said lily paste.

[0043] The preparation method of the said cleaning agent is: take 0.01 g of Span-60 and 0.5 g of sodium citrate, mix and add 100 mL of water, stir at 200 r / min under water bath heating at 50 °C for 10 min; continue to add 0.3 g of sodium benzoate and 20 mL of ethanol, and stir at 100 r / min for 8 min.

[0044] Example 5

[0045] A preparation method of lily paste is as follows:

[0046] The fresh lily bulbs are separated into segments, and 500 g of fresh lily scales are taken and soaked in 1500 mL of water; 3 mg of ozone gas is continuously introduced into the above water for 1 min; after adding 80 mL of cleaning agent, it is oscillated and mixed for 1 min, and the fresh lily scales are taken out and air-dried for 1 h; then it is added to hot water at 90 °C for blanching for 6 min; taken out and placed in 800 mL of 0.2% citric acid aqueous solution for color protection for 3 min; taken out and steamed and softened at 100 °C for 10 min; then put into a high-speed tissue homogenizer at 5000 r / min for pulping for 1 min; sterilized at 100 °C for 15 min and cooled at room temperature; filled into a composite package at 100 g per portion and vacuumized to obtain the said lily paste.

[0047] The preparation method of the said cleaning agent is: take 0.01 g of Tween-80 and 0.5 g of sodium citrate, mix and add 100 mL of water, stir at 200 r / min under water bath heating at 50 °C for 10 min; continue to add 0.3 g of sodium benzoate and 20 mL of ethanol, and stir at 100 r / min for 8 min.

[0048] Example 6

[0049] A preparation method of lily paste is as follows:

[0050] The fresh lily bulbs are separated into petals, and 500 g of fresh lily scales are taken and soaked in 1500 mL of water; 3 mg of ozone gas is continuously introduced into the above water for 1 min; 80 mL of a cleaning agent is added and shaken and mixed for 1 min, and then the fresh lily scales are taken out and air-dried for 1 h; then they are added to hot water at 90 °C and blanched for 6 min; taken out and placed in 800 mL of 0.2% citric acid aqueous solution for color protection for 3 min; taken out and cooked and softened at 100 °C for 10 min, then put into a high-speed tissue homogenizer at 5000 r / min and ground for 1 min; sterilized at 100 °C for 15 min and cooled to room temperature; packed in a composite package at 100 g per portion and vacuumized to obtain the said lily paste.

[0051] The preparation method of the said cleaning agent is as follows: Take 0.01 g of nisin and 0.5 g of sodium citrate, mix and add to 100 mL of water, stir at 200 r / min under water bath heating at 50 °C for 10 min; continue to add 0.3 g of sodium benzoate and 20 mL of ethanol, and stir at 200 r / min for 8 min.

[0052] Example 7

[0053] A preparation method of lily paste is as follows:

[0054] The fresh lily bulbs are separated into petals, and 500 g of fresh lily scales are taken and soaked in 1500 mL of water; 3 mg of ozone gas is continuously introduced into the above water for 1 min; after adding 80 mL of a cleaning agent, it is shaken and mixed for 1 min, and then the fresh lily scales are taken out and air-dried for 1 h; then they are added to hot water at 90 °C and blanched for 6 min; taken out and placed in 800 mL of 0.2% citric acid aqueous solution for color protection for 3 min; taken out and cooked and softened at 100 °C for 10 min, then put into a high-speed tissue homogenizer at 5000 r / min and ground for 1 min; sterilized at 100 °C for 15 min and cooled to room temperature; packed in a composite package at 100 g per portion and vacuumized to obtain the said lily paste.

[0055] The preparation method of the said cleaning agent is as follows: Take 5 mg of nisin and 5 mg of stevioside, 0.5 g of sodium citrate, mix and add to 100 mL of water, stir at 200 r / min under water bath heating at 50 °C for 10 min; continue to add 0.3 g of sodium benzoate and 20 mL of ethanol, and stir at 200 r / min for 8 min.

[0056] Comparative Example 1

[0057] A preparation method of lily paste is as follows:

[0058] The fresh lily bulbs are separated into segments. Take 500 g of fresh lily scales and soak them in 1500 mL of water. At the same time, continuously introduce 3 mg of ozone gas into the above water for 1 minute, shake for 1 minute, take out the fresh lily scales and air-dry for 1 hour; then add them to hot water at 90 °C and blanch for 6 minutes; take out and place them in 800 mL of 0.2% citric acid aqueous solution for color protection for 3 minutes; then carry out softening by steaming at 100 °C for 10 minutes; put them into a high-speed tissue grinder at 5000 r / min and grind for 1 minute; sterilize at 100 °C for 15 minutes, and cool at room temperature; pack them into a composite package at 100 g per portion and vacuumize to obtain the said lily puree.

[0059] Comparative Example 2

[0060] A preparation method of lily puree is as follows:

[0061] The fresh lily bulbs are separated into segments. Take 500 g of fresh lily scales and soak them in 1500 mL of water; add 80 mL of cleaning agent and shake and mix for 1 minute, take out the fresh lily scales and air-dry for 1 hour; then add them to hot water at 90 °C and blanch for 6 minutes; take out and place them in 800 mL of 0.2% citric acid aqueous solution for color protection for 3 minutes; take out and carry out softening by steaming at 100 °C for 10 minutes, then put them into a high-speed tissue grinder at 5000 r / min and grind for 1 minute; sterilize at 100 °C for 15 minutes, and cool at room temperature; pack them into a composite package at 100 g per portion and vacuumize to obtain the said lily puree.

[0062] The preparation method of the said cleaning agent is: take 5 mg of nisin and 5 mg of stevioside, 0.5 g of sodium citrate, mix and add 100 mL of water, stir at 200 r / min under a water bath at 50 °C for 10 minutes; continue to add 0.3 g of sodium benzoate and 20 mL of ethanol, and stir at 100 r / min for 8 minutes.

[0063] Test Example 1

[0064] Pesticide residue test

[0065] During the planting process, the pesticides sprayed will directly contact the surface of the lily scales, and most of the pesticides adhere to them. In addition, the waxy layer on the scale surface hinders the penetration of pesticides into the interior, making more pesticides remain on the surface. At the same time, the lily scales wrap around each other, and it is difficult to thoroughly wash the gaps between the internal scales during cleaning. Even after soaking and rinsing, some hidden parts may still retain pesticides. Therefore, the pesticide residues in edible lilies are mainly concentrated in the scales.

[0066] Propiconazole: Lilies are vulnerable to fungal diseases such as leaf spot and rust during their growth process. Propiconazole is a systemic triazole fungicide with protective and therapeutic effects. It can be absorbed by the roots, stems, leaves and other parts of lilies and conducted within the plant. By inhibiting the biosynthesis of ergosterol in the fungal cell membrane, it damages the structure and function of the fungal cell membrane, thereby preventing the growth and reproduction of fungi and achieving the purpose of disease control. Therefore, it is often used in lily cultivation.

[0067] Cyprodinil: Botrytis cinerea of lilies is one of the important diseases in lily production. Cyprodinil has good control effects on Botrytis cinerea and other pathogens. It acts on the mitosis process of fungal cells and inhibits the growth and infection of the pathogens. In lily cultivation, in order to control Botrytis cinerea and other related diseases, cyprodinil is used for spraying or root irrigation treatment, etc.

[0068] Flutriafol: For some soil-borne diseases and leaf diseases of lilies, flutriafol is an effective control agent. Flutriafol belongs to triazole fungicides and has characteristics such as strong systemic absorption and long residual efficacy. It can inhibit the biosynthesis of sterols in fungi and has good control effects on diseases caused by various basidiomycetes and ascomycetes fungi. It is often used in lily cultivation to control rust, leaf spot, etc. to ensure the healthy growth of lilies.

[0069] During the cleaning process of the lily puree products prepared in Examples 1-7 and Comparative Examples 1-2, after taking 1 g of the washed sample and mashing it, 50 mL of acetonitrile was used for extraction, and dispersive solid-phase extraction was used for purification. Detection was carried out using a liquid chromatography-mass spectrometry (Shimadzu, model: LCMS-8050). Monitor and record the real-time data of lily pesticide residues. The results are shown in Table 1.

[0070] Table 1 Pesticide residue test results

[0071]

[0072] Note: According to the standard conversion principle, the pesticide residue limits that can be co-detected by this method in lily (dry) in GB 2763-2021 are converted into the pesticide residue limits of lily finished products. Among them, the pharmacopoeia limit value of propiconazole is 0.20 mg / kg, the pharmacopoeia limit value of cyprodinil is 1.00 mg / kg, and the pharmacopoeia limit value of flutriafol is 0.20 mg / kg.

[0073] Examples 1-7 compared with Comparative Example 1 showed that in the preparation process of lily puree, the combination of cleaning agent and ozone played a key role in reducing pesticide residues. Chitosan, sodium alginate, and stevioside added in Examples 1-3 have adsorption and complexation abilities, can bind to pesticide molecules, and promote their detachment from the lily surface into the cleaning solution. Although the chitosan added in Example 1 has certain antibacterial properties, similar to the sodium alginate added in Example 2, it is prone to form gels or precipitates when encountering some high-valent metal ions, limiting its application in the cleaning agent used in the present invention. The surfactants added in Examples 4 and 5 can better change the surface properties of the cleaning solution, enabling pesticides to form a stable dispersion system therein. In contrast, during the lily cleaning process in Examples 6-7, the molecular structure of nisin contains special active regions, which may reduce the binding force between the drug and the lily surface. For pesticide residues such as propiconazole, cyprodinil, and flutriafol, it can more effectively wash them off from the gaps, depressions, etc. on the lily surface, and can decompose quickly in the natural environment to avoid environmental pollution.

[0074] Furthermore, in Example 7, the use of stevioside and nisin in the cleaning agent can enhance the removal effect of pesticide residues. During the growth process of lilies, pesticide residues may be wrapped by biological membranes, forming a protective structure that increases the difficulty of cleaning. Among them, nisin can destroy these biological membrane structures, expose the encapsulated pesticides, making them more likely to come into contact with other components in the cleaning agent and water, and then be removed by cleaning; it also has good biocompatibility and environmental friendliness. The added stevioside and nisin can interact with the hydroxyl radicals and superoxide generated by ozone, regulate oxidative stress, damage the fungal cell membrane, make the reactive oxygen free radicals more likely to enter the cell interior, enhance oxidative damage; it also remodels the surface structure of lily cells, changes the surface properties of the petals, promotes ozone adsorption and penetration, and the reactive oxygen free radicals generated by decomposition in water also contribute to the oxidation reaction, thereby enhancing the activity of functional auxiliaries. The two complement each other, providing technical support for improving the quality and safety of the subsequent prepared lily puree products.

[0075] Test Example 2

[0076] Stability test

[0077] The lily puree products prepared in Examples 1-7 and Comparative Examples 1-2 were exposed to air at a temperature of 25 °C and a humidity of 55% for 1 day, 3 days, and 5 days to study the change rules of the activities of polyphenol oxidase and peroxidase during storage, and observe the change of the lily color.

[0078] Polyphenol oxidase (Solarbio; Catalog number: BC0195) and peroxidase (Solarbio; Catalog number BC0095) were determined according to the methods described in the commercial kits. 0.1 g of the lily puree products prepared in Examples 1-7 and Comparative Examples 1-2 were homogenized in 1 mL of the kit extract respectively, and the supernatant was taken after centrifugation to determine the activities of polyphenol oxidase and peroxidase. Polyphenol oxidase can catalyze catechol to produce o-benzoquinone, and the activity of polyphenol oxidase was calculated by analyzing the characteristic light absorption of o-benzoquinone at 410 nm. The peroxidase activity was based on the peroxidation of a specific substrate catalyzed by peroxidase, with characteristic light absorption at 470 nm. The results are shown in Table 2.

[0079] Table 2 Stability test results

[0080]

[0081] During the preparation of lily puree, the combined use of cleaning agent and ozone has a key impact on the activity values of polyphenol oxidase and peroxidase. Natural macromolecular compounds such as chitosan, sodium alginate, and stevioside added to the cleaning agent in Examples 1-3 have poor solubility in water and are difficult to form a dense and effective protective film uniformly on the surface of lilies. The amino and hydroxyl groups and other active groups in their molecular structures can interact with enzyme molecules, partially covering the active sites of the enzymes, thereby inhibiting the progress of enzymatic reactions. The inhibitory effect is not stable enough and the effect is relatively limited. The surfactants added to the cleaning agent in Examples 4-5, Span-60 and Tween-80, can both reduce the surface tension of the cell surface, reduce the release amount of intracellular enzymes, and greatly reduce the contact opportunities between enzymes and substrates, thereby effectively reducing the activities of polyphenol oxidase and peroxidase. However, this effect is mainly concentrated on the contact level between enzymes and substrates, and the effect on the active sites of enzymes themselves is relatively weak. The addition of nisin in the cleaning agent in Example 6 can specifically and tightly bind to enzyme molecules, directly acting on the active center or key parts of the enzymes, and fundamentally inhibiting the activities of polyphenol oxidase and peroxidase. Examples 1-7 and Comparative Example 1 involve ozone technology, which can directly attack the active center structure of polyphenol oxidase and peroxidase, resulting in a change in the spatial conformation of the enzymes and ultimately losing their catalytic activity. Further, the free radicals generated by the decomposition of ozone in water also actively participate in the oxidative modification process of polyphenol oxidase and peroxidase, enhancing the inhibition of enzyme activity.

[0082] Example 7 Stevioside and nisin were compounded, and the activities of polyphenol oxidase and peroxidase in the prepared lily puree were more effectively regulated, with significantly reduced enzyme activities. This indicates that the synergistic effect of the selected functional adjuvant and ozone has a unique and subtle mechanism in regulating the activities of polyphenol oxidase and peroxidase. Stevioside has certain hydrophilicity, and its hydrophilic property may be utilized in the cleaning agent to initially dissolve and disperse some hydrophilic stains, helping the stains to detach from the surface of the object. At the same time, it may have a certain solubilizing effect on nisin in the cleaning agent, making the formulation system of the cleaning agent more stable. By adjusting the microenvironment around the enzyme, such as changing the local pH and ionic strength, the microenvironment where the enzyme is located becomes more stable, enhancing the resistance of the enzyme molecule to the attack of free radicals, and enabling the active site of the enzyme to better maintain the integrity of its structure and function when facing the attack of free radicals.

[0083] Stevioside and nisin were compounded and then collaborated with the free radicals generated by ozone to guide the free radicals to precisely attack the active site of the enzyme, effectively reducing the color change of the lily puree obtained in subsequent preparation due to enzymatic reactions, and ensuring the stability of the lily puree during storage.

Claims

1. A preparation method of lily paste, characterized in that it comprises the following steps: fresh lily bulbs → petal separation → cleaning → blanching → color protection → steaming and softening → grinding → sterilization → cooling → vacuum packaging → finished product.

2. The preparation method of the lily puree according to claim 1, characterized in that, It comprises the following steps: performing petal separation treatment on fresh lily bulbs; adding 300 - 800 g of fresh lily scales to 1000 - 2000 mL of water for soaking; continuously introducing 1 - 3 mg of ozone gas into the above water for 1 - 3 min; adding 50 - 100 mL of cleaning agent and then performing oscillating mixing for 1 - 3 min, taking out the fresh lily scales and air-drying for 0.5 - 2 h; then adding to hot water for blanching for 5 - 10 min; taking out and placing in 500 - 1000 mL of citric acid aqueous solution for color protection for 1 - 5 min; taking out and performing steaming and softening for 8 - 12 min and then grinding at 3000 - 8000 r / min for 1 - 3 min; taking out and performing sterilization for 10 - 20 min, and cooling at room temperature; packing into a composite package at 80 - 150 g per package and then vacuumizing to obtain the lily paste.

3. The preparation method of the lily puree according to claim 1 or 2, characterized in that, The preparation method of the cleaning agent is: taking 5 - 100 mg of functional auxiliary agent, 0.3 - 0.8 g of sodium citrate, mixing and adding to 50 - 100 mL of water, stirring at 30 - 80 °C and 100 - 200 r / min for 5 - 15 min; then successively adding 0.1 - 0.5 g of sodium benzoate and 10 - 30 mL of ethanol, and stirring at 100 - 200 r / min for 8 - 10 min.

4. The preparation method of the lily puree according to claim 1 or 3, characterized in that, The functional auxiliary agent is at least one of chitosan, sodium alginate, stevioside, span - 60, tween - 80, nisin.

5. The preparation method of the lily puree according to claim 1 or 2, characterized in that, In the blanching step, the temperature of the hot water is 80 - 100 °C.

6. The preparation method of the lily paste according to claim 1 or 2, characterized in that, In the color protection step, the concentration of the citric acid solution is 0.15 - 0.25%.

7. The preparation method of the lily paste according to claim 1 or 2, characterized in that, In the steaming and softening step, the steaming temperature is 100 - 120 °C.

8. The preparation method of the lily puree according to claim 1 or 2, characterized in that, In the sterilization step, the sterilization temperature is 90 - 120 °C.

9. A lily puree, characterized in that, Prepared by using the preparation method according to any one of claims 1 - 8.

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