Watermelon essence and preparation method thereof

Abstract

The invention relates to the technical field of microcapsules, in particular to watermelon essence and a preparation method thereof. The watermelon essence is composed of a composite core material and a wall material, the composite core material comprises a watermelon aldehyde pre-clathration core material, cis-3-hexenol, trans-2-hexenal, beta-ionone, leaf acetate and other flavor substances, and the wall material is coated with a pre-clathration layer and a composite nano layer from inside to outside in sequence. The three-stage process of reducing high-temperature volatilization loss in the preparation process through watermelon aldehyde pre-clathration, realizing precise cladding through nano-emulsification and preparing micro powder through spray drying and curing is adopted, so that the three problems of thermal instability, poor slow release property and high cost existing in the field of watermelon essence for a long time are solved, and the watermelon essence has the advantages of high embedding rate, uniform particle size distribution, low cost and the like. The effects of resisting high-temperature processing and prolonging the slow release property are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of microcapsules, in particular to a watermelon essence and a preparation method thereof. Background Art

[0002] Flavors are concentrated mixtures of natural or synthetic flavoring substances. Their core function is to impart specific flavors and aromas to foods, compensate for flavor loss during processing, and enhance the sensory quality of the product. Watermelon flavor, as a representative of water-soluble flavors, is widely used in: solid beverages such as instant juice powder and milk tea powder, confectionery products such as hard candy and jelly candy, dairy products such as flavored yogurt and ice cream, and baking premixes such as cakes and biscuits. Although traditional liquid watermelon flavor has a rich flavor, the volatility of watermelon aldehyde (C9 aldehyde) is >60% at 50°C and the retention rate after baking at 180°C is <30%. Its heat sensitivity, volatility, and chemical instability severely limit its application effectiveness in industrial production.

[0003] The current application of watermelon flavoring faces four major technical bottlenecks: ① Volatility loss: Core flavor substances, such as cis-6-nonenal and watermelon aldehyde, have low boiling points and volatilize by over 30% during mixing, drying, and storage, resulting in insufficient aroma intensity in the finished product. ② Poor processing tolerance: Aldehydes oxidize and decompose during baking temperatures >120°C or high-temperature sterilization, producing unpleasant flavors such as grassy notes. High temperatures also cause the reaction of aroma precursors to fail. ③ Uncontrollable release: Liquid flavoring is released prematurely when it encounters moisture in solid beverages, resulting in a rapid aroma decay during brewing. Due to premature volatilization during baking, a "baked aroma" cannot be formed. ④ Physical compatibility defects: The liquid form is difficult to mix evenly with powdered raw materials, which can easily cause clumping and uneven flavor distribution.

[0004] In view of the above-mentioned related technologies, there is an urgent need in this field to develop a watermelon flavor with thermal processing stability and directional release. Summary of the Invention

[0005] In order to meet the requirements of watermelon essence with fresh, juicy and sweet watermelon flavor, high temperature processing resistance and prolonged sustained release, a watermelon essence and a preparation method thereof are provided by nano-microcapsule technology.

[0006] In a first aspect, the present application provides a watermelon essence, which adopts the following technical solution: A watermelon flavor is composed of a composite core material and a wall material; the composite core material is prepared from the following raw materials in parts by weight: 3.5-5.5 parts of a watermelon aldehyde pre-encapsulation core material, 3-5 parts of cis-3-hexenol, 3-5 parts of trans-2-hexenal, 2-3.5 parts of β-ionone, 1.5-3 parts of leaf acetate, and 1-5 parts of other flavor substances; the wall material is sequentially coated from the inside out, comprising a pre-encapsulation layer and a composite nanolayer.

[0007] By adopting the above scheme, the core material formula of watermelon flavor is based on the aldehyde aroma of watermelon aldehyde, the grassy aroma of cis-3-hexenol, and the fruity sweet aroma of β-ionone, supplemented by leaf acetate and other flavor substances to enhance the freshness. The real flavor layers of watermelon are simulated through precise proportions to obtain a fresh, juicy and sweet watermelon flavor.

[0008] Preferably, the composite core material is prepared by the following raw materials in parts by weight: 4-5 parts of watermelon aldehyde pre-inclusion core material, 3.8-4.7 parts of cis-3-hexenol, 3.8-4.7 parts of trans-2-hexenal, 2.4-3.2 parts of β-ionone, and 2-2.5 parts of leaf acetate. and 2-4 portions of other flavoring substances.

[0009] Preferably, the other flavor substances in the composite core material are one or more of trans-2,6-nonadienal, hexanal, (E,Z)-2,6-nonadien-1-ol, ethyl acetate, γ-decalactone, linalool and ethyl maltol.

[0010] By adopting the above scheme, other flavor substances are mainly used to enhance the flavor layering, simulate the aroma characteristics of real watermelon, and improve the fullness of the taste. The various flavor substances synergistically enhance the effect. Trans-2,6-nonadienal is compounded with watermelon aldehyde to produce a green and fresh flavor; γ-decalactone and β-ionone are compounded to produce a superposition of creamy sweetness and floral sweetness, simulating the ripe and sweet flavor of sandy watermelon.

[0011] Preferably, the pre-encapsulation layer in the wall material is hydroxypropyl-β-cyclodextrin.

[0012] Preferably, the composite nanolayer in the wall material is made from the following raw materials in parts by weight: 25-35 parts of zein, 12.5-17.5 parts of chitosan, 0.5-1.2 parts of antioxidant, 1-1.5 parts of lecithin, and 1-2 parts of sucrose fatty acid ester.

[0013] The composite nano-layer double emulsifier, lecithin and sucrose fatty acid ester, makes the nanoparticle dispersion index <0.2, effectively improving the core material loading rate.

[0014] Preferably, the antioxidant in the composite nanolayer is a mixture of rosemary extract and ascorbyl palmitate in a mass ratio of (2-4):1.

[0015] The fat-soluble antioxidants rosemary extract and ascorbyl palmitate are preferably positioned in the hydrophobic area of ​​zein to directly protect the easily oxidized components in the core material. At the same time, they work together with the amino groups of chitosan and the sulfur amino acids of zein to scavenge free radicals and improve the antioxidant protection performance.

[0016] Preferably, in the composite nanolayer, the sucrose fatty acid ester is SE-15; and the lecithin PC is ≥90%.

[0017] By adopting this approach, the wall material utilizes a synergistic system of pre-encapsulated layers and composite nanolayers. The inner layer utilizes hydroxypropyl-β-cyclodextrin, forming a host-guest inclusion complex within its hydrophobic cavity, significantly reducing volatile losses. The outer layer, a zein-chitosan composite nanolayer, provides physical barrier and environmentally responsive protection. Compared to single-layer microcapsules, this design achieves dual controlled release, addressing flavor escape and oxidation during processing and storage. Its component design meets the food industry's core requirements for natural, efficient, and low-cost performance.

[0018] Hydroxypropyl-β-cyclodextrin has low hemolytic activity, is basically not decomposed and metabolized in the human body, and does not accumulate. It has almost no irritation to muscles and mucous membranes. The sulfur amino acids in zein and the added antioxidants form a free radical scavenging system, and the oxidation induction period of unsaturated components in the core material is extended by 3 times.

[0019] In a second aspect, the present application provides a method for preparing watermelon flavor, which adopts the following technical solution: S1 Raw material preparation: weigh the raw materials according to the proportion; Preparation of S2 pre-inclusion core material: watermelon aldehyde, hydroxypropyl-β-cyclodextrin and water were stirred and mixed under nitrogen protection for 1-3 hours, refrigerated at 4°C for crystallization, and filtered and dried to obtain watermelon aldehyde pre-inclusion core material; S3 nanoemulsification: NaOH solution is added dropwise to the zein / chitosan mixed solution to adjust the pH and allow to stand to form a composite aqueous phase; the watermelon aldehyde pre-inclusion core material prepared in S2, cis-3-hexenol, trans-2-hexenal, β-ionone, leaf acetate, other flavoring substances, lecithin, sucrose fatty acid esters, and antioxidants are mixed and dissolved in an organic solvent to form an oil phase, which is then injected into the aqueous phase; after high-speed shear emulsification, high-pressure homogenization at 100-200 MPa is performed to obtain a nanoemulsion; S4 high temperature spray drying: filter the nanoemulsion through a 200 mesh sieve to remove bubbles and impurities, heat to 40°C, adjust the feed rate to 18-22L / h, spray dry into powder under the conditions of inlet air temperature of 155-165°C, outlet air temperature of 70-80°C, and atomization pressure of 0.7-1.0MPa; S5 sieving: 40 mesh sieve; S6 product quality inspection and filling; S7 foreign body detection, packaging.

[0020] By adopting the above scheme, the hydroxypropyl-β-cyclodextrin pre-encapsulation layer forms a "molecular armor", which enables watermelon aldehyde to withstand high temperatures and obtain thermal stability; high-pressure homogenization and narrow distribution atomization make the encapsulation rate reach 92.5%, and the spray drying temperature is compatible with existing food production lines, without the need for equipment modification.

[0021] Preferably, the S2 pre-encapsulated core material is prepared by dissolving hydroxypropyl-β-cyclodextrin in ultrapure water at 40-50°C to obtain a transparent and viscous hydroxypropyl-β-cyclodextrin solution. Watermelon aldehyde is slowly added dropwise to the hydroxypropyl-β-cyclodextrin solution with stirring, and nitrogen protection is applied at a flow rate of 0.5 L / min. The mixture is placed in a water bath at 43-48°C and protected from light for 1-3 hours, and the solution changes from transparent to a milky white suspension; the mixture is transferred to a 4°C environment and allowed to stand for 10-12 hours to precipitate white crystals; the crystals are collected by suction and spread on a tray, and dried in a vacuum drying oven at 40-50°C and -0.07 to -0.09 MPa for 4-5 hours, and passed through an 80-mesh sieve to obtain a white powder of the pre-encapsulated core material.

[0022] By adopting the above solution, the pre-encapsulated core material produced by this process can withstand high-temperature spray drying, and the watermelon aldehyde retention rate is increased from ≤50% in the traditional process to ≥95%, providing core stability guarantee for the nano-microcapsules.

[0023] Preferably, the S2 pre-inclusion core material is prepared by mixing watermelon aldehyde, hydroxypropyl-β-cyclodextrin and ultrapure water in a mass ratio of 1:(13-15):(55-60).

[0024] Preferably, the composite aqueous phase in the S3 nanoemulsion is prepared by the following steps: mixing and dissolving zein and 80% ethanol solution in a mass ratio of 1-(4-5) to obtain a zein solution; mixing and dissolving chitosan and 0.8% acetic acid solution in a mass ratio of 1-(20-22) to obtain a chitosan solution; mixing the zein solution and the chitosan solution, removing ethanol by rotary evaporation at 50°C -0.08MPa, adding ultrapure water to the system after evaporation to restore the volume to the total volume before evaporation, and obtaining a zein / chitosan mixed solution; adding 0.1MNaOH solution dropwise to the zein / chitosan mixed solution, with a quantitative pump flow rate of 5mL / min, adjusting the pH to 6.0-7.0 and standing for 20-40 minutes to form a composite aqueous phase; electrostatic crosslinking of zein and chitosan to form a double network gel.

[0025] Preferably, the oil phase in the S3 nanoemulsion is prepared by the following steps: mixing the watermelon aldehyde pre-inclusion core material prepared in S2, cis-3-hexenol, trans-2-hexenal, β-ionone, leaf acetate, other flavor substances, lecithin, sucrose fatty acid ester and antioxidant to obtain a premixed oil phase, dissolving the premixed oil phase in anhydrous ethanol solution at a mass ratio of 1:(5-7), ultrasonically treating at 35-45°C and 300-400W for 5-10 minutes until completely dissolved, and concentrating to a paste with 40% solids by nitrogen blowing to form an oil phase.

[0026] Preferably, in the S3 nanoemulsification, the oil phase is heated to 55-65°C and slowly added to the water phase heated to 50°C. The water phase and the oil phase are mixed in a mass ratio of 10:(0.8-1.2), and high-speed shear emulsification is performed: 10000-13000rpm, 3-5 minutes, to obtain a crude emulsion; the crude emulsion is homogenized at 130-150MPa and recycled 3 times; and immediately cooled to 25°C to obtain a nanoemulsion.

[0027] Preferably, the microcapsule has a particle size of 100-200 nm, an encapsulation efficiency of ≥90%, and a loading of 15-20 wt%.

[0028] This solution uses a three-stage process of pre-encapsulation to reduce volatile losses, nano-emulsification to achieve precise coating, and spray drying and solidification into micropowders. It breaks through the three long-standing problems of thermal instability, poor sustained release, and high cost in the field of watermelon flavors. It has an encapsulation rate exceeding 92%, uniform particle size distribution, and is resistant to high-temperature processing and instantaneous cold water dispersibility. It provides a process solution that combines high performance and low cost for highly volatile and heat-sensitive flavors.

[0029] In summary, this application has the following beneficial effects: 1. This application describes a watermelon flavor prepared in this application. The core material formula is based on the aldehyde aroma of watermelon aldehyde, the grassy aroma of cis-3-hexenol, and the fruity sweetness of β-ionone, supplemented by leaf acetate and other flavoring substances to enhance the sense of freshness. Through precise proportions, the flavor layers of real watermelon are simulated to achieve a fresh, juicy, and sweet watermelon flavor. The wall material is a synergistic system of pre-encapsulation layer and composite nanolayer. The inner layer uses hydroxypropyl-β-cyclodextrin to form a host-guest inclusion complex through its hydrophobic cavity, significantly reducing volatile losses. The outer layer is a zein / chitosan composite nanolayer that provides physical barrier and environmentally responsive protection. Compared to single-layer microcapsules, this design achieves dual controlled release, solving the problems of flavor escape and oxidation during processing and storage. Its component design meets the food industry's core requirements for naturalness, efficiency, and low cost.

[0030] 2. The present application discloses a method for preparing a watermelon flavor, which uses a three-stage process of pre-encapsulation of watermelon aldehyde to reduce volatilization losses, nanoemulsification to achieve precise coating, and spray drying and solidification into micropowders. This process solves the three long-standing problems in the field of watermelon flavors, namely thermal instability, poor sustained-release properties, and high costs. The method has the characteristics of high encapsulation rate, uniform particle size distribution, resistance to high-temperature processing, and prolonged sustained-release properties, providing a process solution with both high performance and low cost for highly volatile and heat-sensitive flavors.

[0031] 3. The present application discloses a method for preparing a watermelon flavor, which aims to encapsulate heat-sensitive volatile flavor substances in the watermelon flavor by adopting a layered structure from the inside out. Watermelon aldehyde adopts a pre-encapsulation layer, and cis-3-hexenol, trans-2-hexenal, β-ionone, leaf acetate, and other flavor substances are protected by a composite nanolayer. This is a very effective double-layer protection strategy that can improve its stability to heat, oxygen, light, humidity, and processing conditions. DETAILED DESCRIPTION

[0032] The technical solution of the present application is further illustrated below through specific embodiments. The specific embodiments do not limit the scope of protection of the present application; some non-essential modifications and adjustments made by others based on the concept of the present application still fall within the scope of protection of the present application.

[0033] Unless otherwise specified, the experimental methods described in the following examples are conventional methods. The reagents and materials described are all commercially available products.

[0034] The present application is further described in detail below with reference to the following examples and comparative examples. Example

[0035] Example 1 A preparation method of watermelon essence, the preparation method is as follows: S1 Raw material preparation: weigh the raw materials according to the proportion; Preparation of S2 pre-encapsulated core material: Dissolve 1400g of hydroxypropyl-β-cyclodextrin in 5800mL of 40-50℃ ultrapure water to obtain a transparent and viscous hydroxypropyl-β-cyclodextrin solution. Slowly add 100g of watermelonaldehyde dropwise to the hydroxypropyl-β-cyclodextrin solution with stirring. Protect with nitrogen at a flow rate of 0.5L / min. Place in a 45℃ water bath and avoid light for 2 hours. The solution turns from transparent to a milky white suspension. Transfer to a 4℃ environment and let stand for 12 hours to precipitate white crystals. Collect the crystals by suction and spread them flat on a tray. Dry in a vacuum drying oven at 45℃, -0.08MPa for 4 hours. Pass through an 80-mesh sieve to obtain a white powder of the pre-encapsulated core material.

[0036] S3 nanoemulsification: 300 g of zein was mixed and dissolved with 1200 mL of 80% ethanol solution to obtain a zein solution; 153 g of chitosan was mixed and dissolved with 3213 mL of 0.8% acetic acid solution to obtain a chitosan solution; after mixing the zein solution and the chitosan solution, the ethanol was removed by rotary evaporation at 50°C -0.08 MPa, and ultrapure water was added to the original mixed volume to obtain a zein / chitosan mixed solution; 0.1 M NaOH solution was added dropwise to the zein / chitosan mixed solution at a flow rate of 5 mL / min with a quantitative pump, the pH was adjusted to 6.55, and the mixture was allowed to stand for 30 minutes to form a composite aqueous phase.

[0037] 44 g of watermelon aldehyde pre-inclusion core material, 41 g of cis-3-hexenol, 41 g of trans-2-hexenal, 29 g of β-ionone, 23 g of leaf acetate, 32 g of other flavor substances, 13 g of lecithin, 16 g of sucrose fatty acid ester and 7 g of antioxidant were mixed to obtain a premixed oil phase; 200 g of the premixed oil phase was dissolved in 1200 mL of anhydrous ethanol solution and mixed, and ultrasonicated at 40°C and 350W for 8 minutes until completely dissolved, and concentrated by nitrogen blowing to a paste with a solid content of 40% to form an oil phase.

[0038] Heat 1000 mL of oil phase to 55-65°C, slowly add it to 100 mL of water phase heated to 50°C, mix, and high-speed shear emulsification: 12000 rpm, 5 minutes to obtain a crude emulsion; the crude emulsion is subjected to 140 MPa high-pressure homogenization, cycled 3 times; immediately cool to 25°C to obtain a nanoemulsion.

[0039] S4 high temperature spray drying: filter the nanoemulsion through a 200 mesh sieve to remove bubbles and impurities, raise the temperature to 40°C, adjust the feed rate to 20L / h, spray dry into powder under the conditions of inlet air temperature of 160°C, outlet air temperature of 75°C, and atomization pressure of 0.9MPa; S5 sieving: 40 mesh sieve; S6 product quality inspection and filling; S7 foreign body detection, packaging.

[0040] Among them, other flavor substances are: 12g trans-2,6-nonadienal, 10g γ-decanolide, 10g ethyl maltol; antioxidants are: 5.25g rosemary extract and 1.75g ​​ascorbyl palmitate.

[0041] Example 2 A preparation method of watermelon essence, the preparation method is as follows: S1 Raw material preparation: weigh the raw materials according to the proportion; Preparation of S2 pre-encapsulated core material: Dissolve 1300g of hydroxypropyl-β-cyclodextrin in 5500mL of 40°C ultrapure water to obtain a transparent, viscous hydroxypropyl-β-cyclodextrin solution. Slowly add 100g of watermelonaldehyde dropwise to the hydroxypropyl-β-cyclodextrin solution with stirring. Flow nitrogen at a flow rate of 0.5L / min in a 43°C water bath. Protect from light and react for 3 hours until the solution turns from transparent to a milky white suspension. Transfer to a 4°C environment and let stand for 10 hours to precipitate white crystals. Collect the crystals by filtration and spread them flat on a tray. Dry in a vacuum drying oven at 40°C, -0.09MPa for 4 hours. Pass through an 80-mesh sieve to obtain a white powder of the pre-encapsulated core material.

[0042] S3 nanoemulsification: 250g of zein was mixed and dissolved with 1250g of 80% ethanol solution to obtain a zein solution; 125g of chitosan was mixed and dissolved with 2500g of 0.8% acetic acid solution to obtain a chitosan solution; after mixing the zein solution and the chitosan solution, the ethanol was removed by rotary evaporation at 50°C -0.08MPa, and ultrapure water was added to the original mixed volume to obtain a zein / chitosan mixed solution; 0.1M NaOH solution was added dropwise to the zein / chitosan mixed solution at a flow rate of 5mL / min with a quantitative pump, the pH was adjusted to 6.0, and the mixture was allowed to stand for 20 minutes to form a composite aqueous phase.

[0043] 35 g of watermelon aldehyde pre-inclusion core material, 30 g of cis-3-hexenol, 50 g of trans-2-hexenal, 35 g of β-ionone, 30 g of leaf acetate, 10 g of other flavoring substances, 10 g of lecithin, 20 g of sucrose fatty acid ester and 5 g of antioxidant were mixed to obtain a premixed oil phase; 200 g of the premixed oil phase was mixed with 1000 mL of anhydrous ethanol solution, and ultrasonicated at 35° C. and 300 W for 10 minutes until completely dissolved, and concentrated by nitrogen blowing to a paste with a solid content of 40% to form an oil phase.

[0044] Heat 1000 mL of the oil phase to 55-65°C, slowly add it to 80 mL of the water phase heated to 50°C, mix, and high-speed shear emulsification: 10,000 rpm, 5 minutes to obtain a crude emulsion; the crude emulsion is subjected to 130 MPa high-pressure homogenization, cycled 3 times; and immediately cooled to 25°C to obtain a nanoemulsion.

[0045] S4 high temperature spray drying: filter the nanoemulsion through a 200 mesh sieve to remove bubbles and impurities, raise the temperature to 40°C, adjust the feed rate to 18L / h, spray dry into powder under the conditions of inlet air temperature of 155°C, outlet air temperature of 70-80°C, and atomization pressure of 0.7MPa; S5 sieving: 40 mesh sieve; S6 product quality inspection and filling; S7 foreign body detection, packaging.

[0046] Among them, other flavor substances are: 10g trans-2,6-nonadienal; antioxidants are: 3.33g rosemary extract and 1.67g ascorbyl palmitate.

[0047] Example 3 A preparation method of watermelon essence, the preparation method is as follows: S1 Raw material preparation: weigh the raw materials according to the proportion; Preparation of S2 pre-encapsulated core material: Dissolve 1500g of hydroxypropyl-β-cyclodextrin in 6000mL of 40-50℃ ultrapure water to obtain a transparent and viscous hydroxypropyl-β-cyclodextrin solution. Slowly add 100g of watermelonal dropwise to the hydroxypropyl-β-cyclodextrin solution with stirring, and purify it with nitrogen protection at a flow rate of 0.5L / min. Place it in a 48℃ water bath and avoid light for 1 hour. The solution will turn from transparent to a milky white suspension. Transfer it to a 4℃ environment and let it stand for 12 hours to precipitate white crystals. Collect the crystals by suction and spread them on a tray. Dry them in a vacuum drying oven at 50℃, -0.07MPa for 5 hours. Pass them through an 80-mesh sieve to obtain a white powder of the pre-encapsulated core material.

[0048] S3 nanoemulsification: 350g of zein was mixed and dissolved with 1400g of 80% ethanol solution to obtain a zein solution; 175g of chitosan was mixed and dissolved with 3850g of 0.8% acetic acid solution to obtain a chitosan solution; after mixing the zein solution and the chitosan solution, the ethanol was removed by rotary evaporation at 50°C and -0.08MPa, and ultrapure water was added to the original mixed volume to obtain a zein / chitosan mixed solution; 0.1M NaOH solution was added dropwise to the zein / chitosan mixed solution at a flow rate of 5mL / min using a quantitative pump, the pH was adjusted to 7.0, and the mixture was allowed to stand for 40 minutes to form a composite aqueous phase.

[0049] 55 g of watermelon aldehyde pre-inclusion core material, 50 g of cis-3-hexenol, 30 g of trans-2-hexenal, 20 g of β-ionone, 15 g of leaf acetate, 50 g of other flavor substances, 15 g of lecithin, 10 g of sucrose fatty acid ester and 12 g of antioxidant were mixed to obtain a premixed oil phase; 200 g of the premixed oil phase was dissolved in 1400 mL of anhydrous ethanol solution and mixed, and ultrasonicated at 45° C. and 400 W for 5 minutes until completely dissolved, and concentrated by nitrogen blowing to a paste with a solid content of 40% to form an oil phase.

[0050] Heat 1000 mL of the oil phase to 65°C, slowly add it to 120 mL of the water phase heated to 50°C, mix, and high-speed shear emulsification: 13000 rpm, 3 minutes to obtain a crude emulsion; the crude emulsion is subjected to 150 MPa high-pressure homogenization, cycled 3 times; and immediately cooled to 25°C to obtain a nanoemulsion.

[0051] S4 high temperature spray drying: filter the nanoemulsion through a 200 mesh sieve to remove bubbles and impurities, raise the temperature to 40°C, adjust the feed rate to 22L / h, spray dry into powder under the conditions of inlet air temperature of 165°C, outlet air temperature of 80°C, and atomization pressure of 1.0MPa; S5 sieving: 40 mesh sieve; S6 product quality inspection and filling; S7 foreign body detection, packaging.

[0052] Among them, other flavor substances are: 10g trans-2,6-nonadienal, 10g γ-decalactone, 10g ethyl acetate, 10g linalool and 10g ethyl maltol; antioxidants are: 9.6g rosemary extract and 2.4g ascorbyl palmitate.

[0053] Example 4 A preparation method of watermelon essence, the preparation method is as follows: S1 Raw material preparation: weigh the raw materials according to the proportion; Preparation of S2 pre-encapsulated core material: Dissolve 1350g of hydroxypropyl-β-cyclodextrin in 5700mL of 40-50℃ ultrapure water to obtain a transparent and viscous hydroxypropyl-β-cyclodextrin solution. Slowly add 100g of watermelonaldehyde dropwise to the hydroxypropyl-β-cyclodextrin solution with stirring. Protect with nitrogen at a flow rate of 0.5L / min. Place in a 45℃ water bath and avoid light for 3 hours. The solution turns from transparent to a milky white suspension. Transfer to a 4℃ environment and let stand for 12 hours to precipitate white crystals. Collect the crystals by filtration and spread them flat on a tray. Dry in a vacuum drying oven at 40℃, -0.07MPa for 4 hours. Pass through an 80-mesh sieve to obtain a white powder of the pre-encapsulated core material.

[0054] S3 nanoemulsification: 280g of zein was mixed and dissolved with 1400g of 80% ethanol solution to obtain a zein solution; 135g of chitosan was mixed and dissolved with 2835g of 0.8% acetic acid solution to obtain a chitosan solution; after mixing the zein solution and the chitosan solution, the ethanol was removed by rotary evaporation at 50°C -0.08MPa, and ultrapure water was added to the original mixed volume to obtain a zein / chitosan mixed solution; 0.1M NaOH solution was added dropwise to the zein / chitosan mixed solution at a flow rate of 5mL / min using a quantitative pump, the pH was adjusted to 6.3, and the mixture was allowed to stand for 30 minutes to form a composite aqueous phase.

[0055] 50 g of watermelon aldehyde pre-inclusion core material, 38 g of cis-3-hexenol, 47 g of trans-2-hexenal, 32 g of β-ionone, 20 g of leaf acetate, 20 g of other flavor substances, 12 g of lecithin, 18 g of sucrose fatty acid ester and 8 g of antioxidant were mixed to obtain a premixed oil phase; 200 mL of the premixed oil phase was dissolved in 1200 mL of anhydrous ethanol solution, and ultrasonicated at 42° C. and 300 W for 8 minutes until completely dissolved, and concentrated by nitrogen blowing to a paste with a solid content of 40% to form an oil phase.

[0056] Heat 1000 mL of the oil phase to 55-65°C, slowly add it to 110 mL of the water phase heated to 50°C, mix, and high-speed shear emulsification: 11000 rpm, 4 minutes to obtain a crude emulsion; the crude emulsion is subjected to 130 MPa high-pressure homogenization, cycled 3 times; immediately cooled to 25°C to obtain a nanoemulsion.

[0057] S4 high temperature spray drying: filter the nanoemulsion through a 200 mesh sieve to remove bubbles and impurities, heat to 40°C, adjust the feed rate to 19L / h, spray dry into powder under the conditions of inlet air temperature of 160°C, outlet air temperature of 70°C, and atomization pressure of 0.9MPa; S5 sieving: 40 mesh sieve; S6 product quality inspection and filling; S7 foreign body detection, packaging.

[0058] Among them, other flavor substances are: 10g of gamma-decalactone and 10g of ethyl maltol; and antioxidants are: 6g of rosemary extract and 2g of ascorbyl palmitate.

[0059] Example 5 A preparation method of watermelon essence, the preparation method is as follows: S1 Raw material preparation: weigh the raw materials according to the proportion; Preparation of S2 pre-encapsulated core material: Dissolve 1460g of hydroxypropyl-β-cyclodextrin in 5900mL of 40-50℃ ultrapure water to obtain a transparent and viscous hydroxypropyl-β-cyclodextrin solution. Slowly add 100g of watermelonal dropwise to the hydroxypropyl-β-cyclodextrin solution with stirring. Protect with nitrogen at a flow rate of 0.5L / min. Place in a 48℃ water bath and avoid light for 2 hours. The solution turns from transparent to a milky white suspension. Transfer to a 4℃ environment and let stand for 11 hours to precipitate white crystals. Collect the crystals by suction and spread them flat on a tray. Dry in a vacuum drying oven at 45℃, -0.09MPa for 4 hours. Pass through an 80-mesh sieve to obtain a white powder of pre-encapsulated core material.

[0060] S3 nanoemulsification: 320 g of zein was mixed and dissolved with 1280 g of 80% ethanol solution to obtain a zein solution; 165 g of chitosan was mixed and dissolved with 3465 g of 0.8% acetic acid solution to obtain a chitosan solution; after mixing the zein solution and the chitosan solution, the ethanol was removed by rotary evaporation at 50°C and -0.08 MPa, and ultrapure water was added to the original mixed volume to obtain a zein / chitosan mixed solution; 0.1 M NaOH solution was added dropwise to the zein / chitosan mixed solution at a flow rate of 5 mL / min using a quantitative pump, the pH was adjusted to 6.8, and the mixture was allowed to stand for 30 minutes to form a composite aqueous phase.

[0061] 40 g of watermelon aldehyde pre-inclusion core material, 47 g of cis-3-hexenol, 38 g of trans-2-hexenal, 24 g of β-ionone, 25 g of leaf acetate, 40 g of other flavor substances, 14 g of lecithin, 12 g of sucrose fatty acid ester and 10 g of antioxidant were mixed to obtain a premixed oil phase; 200 mL of the premixed oil phase was dissolved in 1300 mL of anhydrous ethanol solution, mixed, and ultrasonically treated at 42° C. and 350 W for 8 min, and concentrated by nitrogen blowing to a paste with a solid content of 40%, thereby forming an oil phase.

[0062] Heat 1000 mL of the oil phase to 55-65°C, slowly add it to 90 mL of the water phase heated to 50°C, mix, and high-speed shear emulsification: 13000 rpm, 5 minutes to obtain a crude emulsion; the crude emulsion is subjected to 150 MPa high-pressure homogenization, cycled 3 times; and immediately cooled to 25°C to obtain a nanoemulsion.

[0063] S4 high temperature spray drying: filter the nanoemulsion through a 200 mesh sieve to remove bubbles and impurities, raise the temperature to 40°C, adjust the feed rate to 21L / h, spray dry into powder under the conditions of inlet air temperature of 165°C, outlet air temperature of 70°C, and atomization pressure of 0.8MPa; S5 sieving: 40 mesh sieve; S6 product quality inspection and filling; S7 foreign body detection, packaging.

[0064] Among them, other flavor substances are: 10g trans-2,6-nonadienal, 10g γ-decanolide, 10g ethyl acetate and 10g linalool; antioxidants are: 7.5g rosemary extract and 2.5g ascorbyl palmitate.

[0065] Comparative Example Comparative Example 1 The same as Example 1, except that no other flavor substances are added to the composite core material, and the composite core material is: 44g watermelon aldehyde pre-encapsulated core material, 41g cis-3-hexenol, 41g trans-2-hexenal, 29g β-ionone and 23g leaf acetate.

[0066] Comparative Example 2 The same as Example 1, except that the addition amount of the composite core material is different. The composite core material is: 30g watermelon aldehyde pre-encapsulated core material, 25g cis-3-hexenol, 25g trans-2-hexenal, 38g β-ionone, 32g leaf acetate, and 15g other flavor substances; other flavor substances are: 5g trans-2,6-nonadienal, 4g γ-decalactone, and 6 ethyl acetate.

[0067] Comparative Example 3 The same as Example 1, except that the addition amount of the composite core material is different. The composite core material is: 58g watermelon aldehyde pre-inclusion core material, 28g cis-3-hexenol, 52g trans-2-hexenal, 14g β-ionone, 12g phytol acetate, 60g other flavor substances; other flavor substances are: 14g trans-2,6-nonadienal, 14g γ-decalactone, 8 ethyl acetate, 10g linalool and 14g ethyl maltol.

[0068] Comparative Example 4 The same as Example 1, except that the addition amount of the composite core material is different. The composite core material is: 30g watermelon aldehyde pre-encapsulated core material, 30g trans-2-hexenal, 35g β-ionone, 22g γ-decanolide and 15g ethyl acetate.

[0069] Comparative Example 5 The same as Example 1, except that the watermelon aldehyde in the composite core material is not pre-enclosed by hydroxypropyl-β-cyclodextrin.

[0070] Comparative Example 6 The same as Example 1, except that the wall material coating material is different: the wall material is coated from the inside to the outside, the pre-encapsulation layer and the composite nanolayer, the pre-encapsulation layer is β-cyclodextrin; the composite nanolayer is made of the following raw materials in parts by weight: 350g casein, 170g chitosan, 7g antioxidant, 13g lecithin, and 16g sucrose fatty acid ester.

[0071] Comparative Example 7 The same as Example 1, except that the wall material coating materials are different: the wall material is coated from the inside to the outside, the pre-encapsulation layer and the composite nanolayer, the pre-encapsulation layer is β-cyclodextrin; the composite nanolayer is made of the following raw materials in parts by weight: 250g sodium alginate, 150g pectin, 7g antioxidant, 13g lecithin, and 16g sucrose fatty acid ester.

[0072] Comparative Example 8 The same as Example 1, except that the antioxidant in the composite nanolayer of the wall material is different, and the antioxidant is: 3g vitamin E, 2g tert-butylhydroquinone.

[0073] Comparative Example 9 The same as Example 1, except that the high-temperature spray drying process parameters are different: the nanoemulsion feed rate is adjusted to 15 L / h, and the nanoemulsion is spray-dried into powder under the conditions of an inlet air temperature of 170°C, an outlet air temperature of 90°C, and an atomization pressure of 1.0 MPa.

[0074] Comparative Example 10 The same as Example 1, except that the nanoemulsification process parameters are different: the oil phase is heated to 70°C and slowly added to the water phase heated to 70°C, the water phase and the oil phase are mixed in a mass ratio of 10:1.5, the water-oil mixture is homogenized under a high pressure of 150 MPa and circulated 3 times; and immediately cooled to room temperature to obtain a nanoemulsion.

[0075] Performance testing 30 people were randomly selected to taste the candies and breads prepared in the above examples and comparative examples to evaluate the aroma restoration, naturalness, and persistence of the watermelon flavor in the hard candies and breads, and to determine consumers' preference for the watermelon flavor. The sensory evaluation score sheet is shown in Table 1: Table 1: Sensory evaluation score of hard candies and bread made with watermelon flavor The watermelon flavors prepared in Examples 1-5 and Comparative Examples 1-10 were used in the production of hard candies and bread, and the test results were obtained through sensory evaluation, as shown in Table 2.

[0076] Table 2 Sensory evaluation scores The results show that the watermelon flavor prepared by Examples 1-5 and the powder flavor obtained by nano-microcapsule technology scored in the range of 91.5-94.5 when making watermelon-flavored hard candies, and scored in the range of 92.4-95.8 when making watermelon-flavored bread. The watermelon flavor exhibits excellent flavor stability and sustained-release performance. No burnt or grassy taste is detected in the hard candies after high-temperature boiling. The evaluators described it as "as refreshing as a freshly cut watermelon", which is significantly better than the traditional process. The flavor layers of the hard candies and bread show a strong green peel feeling in the early stage of chewing, release a sweet and mellow melon aroma in the middle stage of chewing, leave a faint mint-like aftertaste after dissolution, and the layer transition is natural.

[0077] Comparative Examples 1-10 scored lower than 76.4 points when making watermelon-flavored hard candies, and scored lower than 79.2 points when making watermelon-flavored bread, indicating that the watermelon flavors prepared in Comparative Examples 1-10 exposed obvious defects in high-temperature processing and oral release. Volatile aldehydes polymerized during the high-temperature processing process. Six evaluators tasted a "muffled sweetness like cooked pumpkin". The aroma was too explosive at the beginning of the mouthfeel, but it rapidly decayed to a faint sweetness after 10 seconds, and the layer separation was low. The evaluators described it as "the flavor was pungent at the beginning, and only saccharin taste was left at the end. The evaluators reported that "it had no taste after chewing a few times, and it felt like eating ordinary sweet candy", and there was "a slight bitter feeling".

[0078] From the above test results, it can be seen that the watermelon flavor prepared by this application uses nano-microcapsule technology to encapsulate HP-β-CD molecules with the zein / chitosan sustained-release layer to solve the three major pain points of traditional watermelon flavor in candy, namely high-temperature decomposition, flavor discontinuity, and short-lasting fragrance, with obvious sensory advantages.

[0079] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as they are within the scope of the present invention, they are protected by patent law.

Claims

1. A watermelon flavor, characterized in that: The invention is composed of a composite core material and a wall material; the composite core material is made from the following raw materials in parts by weight: 3.5-5.5 parts of watermelon aldehyde pre-encapsulated core material, 3-5 parts of cis-3-hexenol, 3-5 parts of trans-2-hexenal, 2-3.5 parts of β-ionone, 1.5-3 parts of leaf acetate and 1-5 parts of other flavor substances; the wall material is coated from the inside to the outside in sequence, with a pre-encapsulated layer and a composite nanolayer.

2. The watermelon essence according to claim 1, characterized in that The other flavor substances in the composite core material are one or more of trans-2,6-nonadienal, hexanal, (E,Z)-2,6-nonadien-1-ol, ethyl acetate, γ-decalactone, linalool and ethyl maltol.

3. The watermelon flavor according to claim 1, characterized in that The composite nano layer in the wall material is prepared from the following raw materials in parts by weight: 25-35 parts of zein, 12.5-17.5 parts of chitosan, 0.5-1.2 parts of antioxidant, 1-1.5 parts of lecithin and 1-2 parts of sucrose fatty acid ester.

4. The watermelon flavor according to claim 1, characterized in that The antioxidant in the composite nanolayer is a compound of rosemary extract and ascorbyl palmitate in a mass ratio of (2-4):

1.

5. A method for preparing the watermelon flavor according to any one of claims 1 to 4, characterized in that: It includes the following steps: S1 Raw material preparation: weigh the raw materials according to the proportion; Preparation of S2 pre-inclusion core material: watermelon aldehyde, hydroxypropyl-β-cyclodextrin and water were stirred and mixed under nitrogen protection for 1-3 hours, refrigerated at 4°C for crystallization, and filtered and dried to obtain watermelon aldehyde pre-inclusion core material; S3 nanoemulsification: NaOH solution is added dropwise to the zein / chitosan mixed solution to adjust the pH and allow to stand to form a composite aqueous phase; the watermelon aldehyde pre-inclusion core material prepared in S2, cis-3-hexenol, trans-2-hexenal, β-ionone, leaf acetate, other flavoring substances, lecithin, sucrose fatty acid esters, and antioxidants are mixed and dissolved in an organic solvent to form an oil phase, which is then injected into the aqueous phase; after high-speed shear emulsification, high-pressure homogenization at 100-200 MPa is performed to obtain a nanoemulsion; S4 high temperature spray drying: filter the nanoemulsion through a 200 mesh sieve to remove bubbles and impurities, heat to 40°C, adjust the feed rate to 18-22 L / h, spray dry into powder under the conditions of inlet air temperature of 155-165°C, outlet air temperature of 70-80°C, and atomization pressure of 0.7-1.0 MPa; S5 sieving: 40 mesh sieve; S6 product quality inspection and filling; S7 Foreign body detection, packaging.

6. The preparation method of watermelon flavor according to claim 5, characterized in that, The S2 pre-encapsulated core material is prepared as follows: hydroxypropyl-β-cyclodextrin is dissolved in 40-50°C ultrapure water to obtain a transparent and viscous hydroxypropyl-β-cyclodextrin solution; watermelonal is slowly added dropwise to the hydroxypropyl-β-cyclodextrin solution with stirring, and nitrogen protection is applied at a flow rate of 0.5 L / min. The solution is kept in a 43-48°C water bath and protected from light for 1-3 hours until the solution turns from transparent to a milky white suspension; the solution is transferred to a 4°C environment and allowed to stand for 10-12 hours to precipitate white crystals; the crystals are collected by filtration and spread on a tray, and dried in a vacuum drying oven at 40-50°C and -0.07 to -0.09 MPa for 4-5 hours, and passed through an 80-mesh sieve to obtain a white powder of the pre-encapsulated core material.

7. The method for preparing the watermelon flavor according to claim 6, wherein The S2 pre-inclusion core material is prepared by mixing watermelon aldehyde, hydroxypropyl-β-cyclodextrin and ultrapure water in a mass ratio of 1:(13-15):(55-60).

8. The method for preparing watermelon flavor according to claim 5, wherein The composite aqueous phase in the S3 nanoemulsion is prepared by the following steps: mixing and dissolving zein with an 80% ethanol solution in a mass ratio of 1-(4-5) to obtain a zein solution; mixing and dissolving chitosan with a 0.8% acetic acid solution in a mass ratio of 1-(20-22) to obtain a chitosan solution; mixing the zein solution and the chitosan solution, removing ethanol by rotary evaporation at 50°C and -0.08 MPa, and adding ultrapure water to the evaporated system to restore the volume to the total volume before evaporation to obtain a zein / chitosan mixed solution; 0.1M NaOH solution was added dropwise to the zein / chitosan mixed solution at a flow rate of 5 mL / min with a quantitative pump. The pH was adjusted to 6.0-7.0 and the mixture was allowed to stand for 20-40 minutes to form a composite aqueous phase. Zein and chitosan were electrostatically cross-linked to form a double network gel.

9. The method for preparing watermelon flavor according to claim 5, wherein The oil phase in the S3 nanoemulsion is prepared by the following steps: mixing the watermelon aldehyde pre-inclusion core material prepared in S2, cis-3-hexenol, trans-2-hexenal, β-ionone, leaf acetate, other flavoring substances, lecithin, sucrose fatty acid esters and antioxidants to obtain a premixed oil phase, dissolving the premixed oil phase in anhydrous ethanol solution at a mass ratio of 1:(5-7), ultrasonically treating at 35-45°C and 300-400W for 5-10 minutes until completely dissolved, and concentrating with nitrogen blow-through to a paste with a solid content of 40%, thereby forming an oil phase.

10. The method for preparing the watermelon flavor according to claim 5, wherein: In the S3 nanoemulsification, the oil phase is heated to 55-65°C and slowly added to the water phase heated to 50°C. The water phase and the oil phase are mixed in a mass ratio of 10:(0.8-1.2). High-speed shear emulsification is performed at 10,000-13,000 rpm for 3-5 minutes to obtain a crude emulsion. The crude emulsion is then subjected to high-pressure homogenization at 130-150 MPa for three cycles. The crude emulsion is then immediately cooled to 25°C to obtain a nanoemulsion.

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