Pomelo-shiso paste and method for preparing the same

Abstract

This invention relates to edible sauces, specifically to a grapefruit wasabi sauce and its preparation method. The preparation method includes: preparing grapefruit juice, grapefruit oil, and grapefruit peel derivatives; cutting wasabi rhizomes and leaves into pieces, mixing with grapefruit juice, pre-cooling, grinding, adding grapefruit oil, and homogenizing to obtain a preliminary sauce; adjusting the pH with whey protein solution, adding tea polyphenols, and dispersing to obtain a suspension; dispersing grapefruit peel derivatives in water to obtain a dispersion, mixing with the suspension, adjusting the pH, and stirring to obtain a composite granular material; adding the composite granular material to the preliminary sauce and dispersing to obtain a semi-finished product; adding granular wasabi, salt, sweetener, and grapefruit pulp, stirring, and filling to obtain grapefruit wasabi sauce. The wasabi sauce prepared by this invention can effectively retain the flavor components ITCs of wasabi, and still has a high content of ITCs after long-term storage; the addition of grapefruit pulp and sweetener to the sauce neutralizes the spiciness and enhances the overall flavor complexity and roundness.

Description

Technical Field

[0001] This invention relates to edible sauces, specifically to a grapefruit wasabi sauce and its preparation method. Background Technology

[0002] When wasabi tissue is broken, glucosinolates hydrolyze to produce volatile and irritating isothiocyanates, which produce a spicy flavor. However, the isothiocyanates produced are highly volatile and easily lost during processing and storage, causing the spicy flavor of the product to decay rapidly, resulting in insufficient spiciness in the finished wasabi paste.

[0003] Existing methods for enhancing the spiciness of finished wasabi paste include: adding exogenous flavor compounds such as mustard oil and isothiocyanate monomers for reinforcement, but the flavor authenticity is insufficient; using microencapsulation technology to encapsulate and protect extracted isothiocyanates, such as complex coagulated microcapsules with gelatin / gum arabic as the wall material, but this method requires pre-extraction of isothiocyanates, and the cost of curing agents such as genipin is high; and adding modified starch and other substances to the wasabi paste to improve the retention of isothiocyanates. However, these solutions either have problems such as complex processes and high costs, or fail to fundamentally solve the problem of in-situ protection of isothiocyanates.

[0004] Grapefruit (Citrus grandis) is rich in citric acid, vitamin C, pectin, and cellulose. Citric acid provides an acidic environment, and grapefruit peel contains abundant fiber, which has a wide range of applications in food.

[0005] To address the aforementioned problems, a technology that incorporates grapefruit ingredients and maintains a stable spicy flavor in wasabi sauce over the long term is still under research. Summary of the Invention

[0006] To address the problems in the background art, the present invention provides a grapefruit wasabi sauce and its preparation method.

[0007] This invention first provides a method for preparing grapefruit wasabi jam, comprising the following steps: Step 1: Juice grapefruit pulp and adjust pH to obtain grapefruit juice; press grapefruit seeds to obtain grapefruit oil; pulp grapefruit peel, treat with sodium hydroxide solution, filter, treat the residue with hydrogen peroxide solution, filter again, grind the residue with water, concentrate and treat with citric acid solution, centrifuge, wash and dry to obtain grapefruit peel derivatives; Step 2: Cut the wasabi root and leaves into pieces, mix with grapefruit juice, pre-cool, grind to obtain a ground mixture, add grapefruit oil and homogenize to obtain the initial sauce; Step 3: Adjust the pH of the whey protein solution, add tea polyphenols, and disperse to obtain a suspension; take grapefruit peel derivatives and disperse them in water to obtain a dispersion, mix with the suspension, adjust the pH again, stir, and obtain composite particulate material; Step 4: Add compound granular material to the initial sauce and disperse to obtain a semi-finished product; then add granular wasabi, salt, sweetener and grapefruit pulp, stir, and fill to obtain grapefruit wasabi sauce.

[0008] Preferably, in step 1, the pH of the grapefruit juice is 3.5-4.

[0009] Preferably, in step 1, grapefruit seeds are washed, dried, and then pressed at low temperature (temperature <50℃) using a screw press, followed by centrifugation to remove impurities, in order to obtain grapefruit oil.

[0010] Preferably, in step 1, the grapefruit peel is pulped using water at a ratio of 1:0.8-2 (by weight of the grapefruit peel). The sodium hydroxide solution treatment involves adding the pulped material to a 3-6 wt% sodium hydroxide solution and heating and stirring for 1-4 hours. The hydrogen peroxide solution treatment involves adding the filter residue to an alkaline solution of 1.5-5 wt% hydrogen peroxide (e.g., adjusting the pH to 10-12 using sodium hydroxide) and heating and stirring for 1-4 hours. The filter residue is then filtered and ground with water to a solid content of 5-10 wt% before grinding to obtain the ground material. The citric acid solution treatment involves adding a 45-55 wt% citric acid aqueous solution and reacting hydrothermally for 0.5-2.5 hours.

[0011] Preferably, the temperature for precooling, grinding and homogenizing in step 2 is 1-6°C.

[0012] Preferably, in step 2, the weight ratio of wasabi rhizome, wasabi leaves, grapefruit juice, and grapefruit oil is 1:(0.5-1):(1-2):(0.25-0.4).

[0013] Preferably, in step 3, the concentration of the whey protein solution is 2-4 wt%.

[0014] Preferably, in step 3, the pH of the whey protein solution is adjusted to 7.5-8.5, and then adjusted again to 3.7-4.2.

[0015] Preferably, in step 3, the weight ratio of whey protein, tea polyphenols, and grapefruit peel derivative is (1.2-1.7):(0.25-0.35):(3-5).

[0016] Preferably, in step 3, the process of dispersing to obtain a suspension includes ultrasonic dispersion at 0-10°C.

[0017] Preferably, in step 3, the grapefruit peel derivative is dispersed in water to obtain a dispersion, and the derivative content is 2-4 wt%.

[0018] Preferably, in step 4, the amount of composite granular material added is 0.85-1.1 times the weight of the initial sauce.

[0019] Preferably, in step 4, the granular wasabi, salt, sweetener, and grapefruit pulp account for 5-20%, 3-8%, 0.001-5%, and 5-15% of the weight of the semi-finished product, respectively.

[0020] Preferably, in step 4, the granular wasabi is made by freeze-drying wasabi rhizomes and wasabi leaves, crushing and screening them into granules, and then granulating them at a granule weight ratio of 1:(1-3).

[0021] Preferably, the sweetener includes at least one of sucrose, glucose, steviol glycosides, D-allulose, sorbitol, erythritol, xylitol, maltitol, and mogrosides.

[0022] The present invention also provides grapefruit wasabi sauce prepared according to the preparation method described above.

[0023] The advantages of this invention compared to the prior art are as follows: This invention uses grapefruit and wasabi to prepare a semi-finished product, and adds granulated wasabi, salt, sweetener and grapefruit pulp. The preparation of the semi-finished product can maintain the retention rate and continuous release ability of high-efficiency wasabi flavor substances. At the same time, the addition of grapefruit pulp and granulated wasabi increases the solid content of the sauce and produces a granular eating texture, thereby improving the eating effect and experience.

[0024] This invention uses whey protein solution to adjust the pH, adds tea polyphenols, and disperses them to obtain a suspension. This suspension is then mixed with a grapefruit peel derivative dispersion, the pH is adjusted again, and the mixture is stirred to obtain composite granular material. This material is then mixed with a primary sauce, and auxiliary ingredients are added to obtain grapefruit wasabi sauce. This sauce has a spicy wasabi flavor and also incorporates the aroma of grapefruit. Furthermore, it makes rational use of different parts of grapefruit and wasabi, reducing raw material waste and showing excellent application prospects. The natural cellulose abundant in grapefruit peel of this invention undergoes alkali treatment to remove hemicellulose, pectin, and other substances, hydrogen peroxide treatment to remove lignin, pigments, and other substances, and further citric acid treatment to partially depolymerize and remove amorphous regions, resulting in cellulose with high crystallinity and high porosity. The resulting interfacial film is dense and stable, effectively blocking oxygen and moisture, and effectively adsorbing and locking volatile isothiocyanates to prevent their volatilization. Furthermore, this invention selects whey protein and adjusts it to a specific pH of 7.5-8.5, allowing it to fully extend and adsorb onto the surface of the grapefruit peel derivative. In addition, tea polyphenols, rich in phenolic hydroxyl groups, can interact hydrophobically and bind with whey protein through hydrogen bonds, further modifying the particle surface and enhancing its interfacial stability and functionality. Furthermore, when the grapefruit peel derivative dispersion is mixed with a suspension containing whey protein / tea polyphenols and the pH is adjusted to 3.7-4.2, the electrostatic repulsion of the whey protein molecules decreases, causing them to tightly entangle with the grapefruit peel derivatives and tea polyphenols, forming stable, dense composite particulate materials. Their large specific surface area and hydrophobic surface regions rapidly adsorb and encapsulate the highly volatile isothiocyanates generated during the preparation process, locking in unstable flavor substances and forming a barrier that effectively isolates them from the external environment, significantly reducing their volatilization and degradation rates. This invention utilizes the positive charge carried by whey protein at pH 3.7-4.2, which electrostatically attracts the negatively charged grapefruit peel derivatives, self-assembling to form interface-stabilized particles for Pickering emulsions.

[0025] This invention selects wasabi rhizomes and leaves and mixes them with grapefruit juice at a low temperature of 1-6℃. This can slow down the inactivation of enzymes, reduce the reactivity of enzymes and other active ingredients, and control the formation rate of isothiocyanates, preventing them from volatilizing instantly due to violent reactions.

[0026] This invention adjusts the pH of grapefruit juice to 3.5-4.0, providing the necessary conditions for the precipitation of whey protein and facilitating the formation of composite particulate materials. In addition, it can effectively inhibit the reaction of active ingredients in wasabi and reduce the formation rate of isothiocyanates.

[0027] This invention utilizes all parts of the pomelo—peel, pulp, and seeds—effectively reducing raw material waste. It also utilizes different parts of the wasabi, such as roots and leaves, reducing the composition of raw materials. Furthermore, this invention rationally utilizes pomelo seeds to obtain pomelo oil for preparing wasabi paste, which can effectively extract and dissolve isothiocyanates, allowing for their preservation and improving the retention rate of ITCs.

[0028] The grapefruit peel derivative prepared by this invention possesses a rigid structure and high crystallinity. It can form a dense interparticle film at the oil-water interface, exhibiting extremely high mechanical strength and resistance to aggregation and agglomeration, as well as high barrier properties against oxygen and moisture. After citric acid treatment, the surface carboxyl groups of the grapefruit peel derivative undergo protonation under acidic conditions, generating electrostatic attraction and hydrogen bonding with positively charged whey protein. Simultaneously, the phenolic hydroxyl groups of tea polyphenols form a multi-layered hydrogen bond network with the surfaces of whey protein and cellulose. All three components self-assemble to form a stable composite particle structure. These composite particles are enriched at the oil-water interface, allowing the antioxidant activity of tea polyphenols to be fully utilized, further inhibiting the oxidative degradation of isothiocyanates and enhancing system stability.

[0029] In this invention, whey protein and tea polyphenols self-assemble to form a tea polyphenol-whey protein complex with an amphiphilic structure. Whey protein provides hydrophobic regions and charged residues, while tea polyphenols provide antioxidant activity and additional hydrogen bond binding sites. Together with grapefruit peel derivatives, it anchors itself at the oil-water interface, resulting in increased interfacial adsorption rate and high interfacial film density. Furthermore, the presence of hydrophobic regions of whey protein enhances its affinity for the oil-water interface, thereby improving the interfacial protection effect and increasing the retention rate of ITCs.

[0030] In this invention, the tea polyphenols in the composite granular material possess extremely strong free radical scavenging capabilities. After accumulating at the oil-water interface, they block the reactive inactivation of isothiocyanates. The presence of whey protein enhances the adsorption of grapefruit peel derivatives at the interface and provides a better amphiphilic balance on the surface of the composite particles. Furthermore, the rigid structure of the grapefruit peel derivatives forms a dense, interlocking film at the oil-water interface, providing a high-strength physical barrier that stabilizes the system and inhibits the decomposition of ITCs. The optimal effect is achieved through the combination of the dispersion containing grapefruit peel derivatives and the composite granular material containing whey protein and tea polyphenols, resulting in a synergistic effect in inhibiting ITC inactivation and preserving ITC content after storage.

[0031] This invention adds grapefruit pulp and sweetener to wasabi sauce, which can neutralize the spiciness, enhance the overall flavor profile and roundness, and bring the product to a balanced state. Detailed Implementation

[0032] The technical solutions described below will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, unless otherwise specified, the raw materials used in the specific embodiments should be food-grade.

[0033] Granular wasabi: Wasabi rhizomes and leaves were freeze-dried separately, then crushed and granulated (selecting particles between 10 and 40 mesh), and composed of rhizomes and leaves in a particle weight ratio of 1:2.5. The wasabi variety used in the examples is Daruma.

[0034] Example 1 Step 1: Select ripe pomelos (Dongshi Early Pomelo (also known as Dai Pomelo)), juice the pomelo pulp directly, then filter it. Adjust the pH of the filtrate to 3.7 with citric acid to obtain pomelo juice. Grapefruit seeds were washed, dried to a water content of 2.73 wt%, and then pressed at low temperature using a screw press (press chamber temperature not exceeding 45℃). After obtaining crude oil, the seeds were centrifuged at 5000 rpm to remove impurities, thus obtaining grapefruit oil.

[0035] Grapefruit peel (without the white pith) and water were blended in a 1:1 weight ratio. A 5wt% sodium hydroxide solution (1.8 times the weight of the grapefruit peel) was added, and the mixture was heated to 80°C and stirred at 80 rpm for 2.5 hours. After cooling to 40°C, the mixture was filtered. A 2.0wt% hydrogen peroxide solution (adjusted to pH 10.5 with sodium hydroxide) (twice the weight of the filter residue) was added to the filter residue, and the mixture was heated to 50°C and stirred at 100 rpm for 2 hours. After cooling to 40°C, the mixture was filtered again. Water was added to the filter residue to dilute it to a solid content of 7.5wt%. The mixture was then ground in a colloid mill for 12 minutes (80 μm gap) to obtain the desired product. The ground material was concentrated to a water content of 35 wt% to obtain a concentrate. Eight times the weight of the concentrate was mixed with a 50 wt% citric acid aqueous solution. The mixture was then placed in a pressure reactor and hydrothermally reacted at 105°C for 1.5 hours. After cooling to room temperature, the mixture was centrifuged at 10,000 rpm for 10 minutes. The centrifuged precipitate was washed three times with water (this process can be combined with multiple centrifugation and washing processes to check whether the residues of sodium hydroxide, hydrogen peroxide, citric acid, etc. meet food safety requirements; the same applies below). The washed solids were freeze-dried to a water content of 3.76 wt% to obtain a grapefruit peel derivative. Step 2: Cut the wasabi rhizome and leaves into pieces (approximately 1cm in length, width, and height), mix with grapefruit juice, pre-cool to 3°C, add to a colloid mill and grind at 3°C ​​for 12 minutes (80μm gap) to obtain ground material, add grapefruit oil and homogenize at 3°C ​​(500 bar) for 5 minutes to obtain the initial sauce; The weight ratio of Daruma wasabi root, wasabi leaves, grapefruit juice, and grapefruit oil is 1:0.6:1.6:0.3. Step 3: Adjust the pH of a 3 wt% whey protein (food grade, model Hilmar 8010, hereinafter the same) solution to 8.0 using sodium hydroxide, add tea polyphenols (food grade, tea polyphenol TP-95, hereinafter the same), and ultrasonically disperse under ice bath conditions (20 kHz, 200 W, 10 min, pulse mode: 5 s on / 3 s off) to obtain a suspension; take grapefruit peel derivative and water, stir and mix at room temperature and homogenize (1000 bar, room temperature, 5 min) to obtain a dispersion with a derivative content of 3 wt%, then mix with the suspension, adjust the pH to 4.0 using citric acid, stir at 500 rpm for 15 min to obtain composite granular material; The weight ratio of whey protein, tea polyphenols, and grapefruit peel derivatives is 1.5:0.3:4. Step 4: Add compound granular material at a weight of 1 times to the initial sauce, and ultrasonically disperse in an ice water bath (20kHz, 150W, 10min) to obtain a semi-finished product; then add 10% granular wasabi, 4.5% salt, 0.02% sweetener mogroside, and 10% grapefruit pulp (granular and sterilized) relative to the weight of the semi-finished product, stir in an ice water bath for 10 minutes, and fill into containers to obtain grapefruit wasabi sauce.

[0036] Example 2 Step 1: Select ripe pomelos (Menglun early pomelo (big puff fruit)), juice the pomelo pulp directly, then filter it. Adjust the pH of the filtrate to 3.6 with citric acid to obtain pomelo juice; Grapefruit seeds are washed, dried to a water content of 2.54 wt%, and then pressed at low temperature using a screw press (press chamber temperature not exceeding 45℃). After obtaining crude oil, the seeds are centrifuged at 5000 rpm to remove impurities, thus obtaining grapefruit oil.

[0037] Grapefruit peel (with the white pith removed) and water were blended at a weight ratio of 1:0.95. A 5.5wt% sodium hydroxide solution (1.75 times the weight of the grapefruit peel) was added, and the mixture was heated to 75°C and stirred at 80 rpm for 2.2 hours. After cooling to 40°C, the mixture was filtered. A 2.2wt% hydrogen peroxide solution (adjusted to pH 10.8 with sodium hydroxide) (2.5 times the weight of the filter residue) was added to the filter residue, and the mixture was heated to 55°C and stirred at 100 rpm for 2.5 hours. After cooling to 40°C, the mixture was filtered, and water was added to the filter residue to dilute it to a final consistency. The material was ground in a colloid mill for 10 min (60 μm gap) with 8 wt% water content to obtain a concentrate. The concentrate was then concentrated to a water content of 32.5 wt%. A 48 wt% citric acid aqueous solution was added at 8.2 times the weight of the concentrate and mixed. The mixture was then placed in a pressure reactor and hydrothermally reacted at 108 °C for 1.7 h. After cooling to room temperature, the mixture was centrifuged at 10,000 rpm for 12 min. The precipitate was washed with water four times. The washed solids were freeze-dried to a water content of 3.91 wt% to obtain a grapefruit peel derivative. Step 2: Cut the wasabi rhizome and leaves into pieces (approximately 1cm in length, width, and height), mix with grapefruit juice, pre-cool to 4°C, add to a colloid mill and grind at 3°C ​​for 10 minutes (80μm gap) to obtain ground material, add grapefruit oil and homogenize at 4°C (500 bar) for 6 minutes to obtain the initial sauce; The weight ratio of wasabi root, wasabi leaves, grapefruit juice, and grapefruit oil is 1:0.65:1.5:0.35. Step 3: Adjust the pH of a 3.5 wt% whey protein solution to 8.2 using sodium hydroxide, add tea polyphenols, and ultrasonically disperse under ice bath conditions (20 kHz, 200 W, 12 min, pulse mode: 5 s on / 3 s off) to obtain a suspension; take grapefruit peel derivative and water, stir and mix at room temperature and homogenize (1000 bar, room temperature, 5 min) to obtain a dispersion with a derivative content of 3.5 wt%, then mix it with the suspension, adjust the pH to 4.2 using citric acid, stir at 500 rpm for 12 min to obtain composite granular material; The weight ratio of whey protein, tea polyphenols, and grapefruit peel derivatives was 1.7:0.35:4.5. Step 4: Add 0.95 times the weight of the composite granular material to the initial sauce, and ultrasonically disperse it in an ice water bath (20kHz, 150W, 10min, pulse mode: 5s on / 3s off) to obtain a semi-finished product; then add 9.5% granular wasabi, 4.2% salt, 2.5% sweetener maltitol and 12.5% ​​grapefruit pulp (granular and sterilized) relative to the weight of the semi-finished product, stir in an ice water bath for 15 minutes, and fill into containers to obtain grapefruit wasabi sauce.

[0038] Comparative Example 1: After filling in Example 1, a pasteurization process of 75°C / 20s was performed, with all other steps remaining the same.

[0039] Comparative Example 2: Compared to Example 1, the preparation of grapefruit oil was omitted and grapefruit oil was not used in step 2, but everything else was the same.

[0040] Comparative Example 3: Compared to Example 1, the grapefruit peel derivative was replaced with an equal weight of gum arabic, and everything else was the same.

[0041] Comparative Example 4: Compared to Example 1, the preparation method of the grapefruit peel derivative omits the treatment process of citric acid aqueous solution, and is as follows: Grapefruit peel (without white pith) and water are pulped at a weight ratio of 1:1. A 5wt% sodium hydroxide solution with a concentration of 1.8 times the weight of the grapefruit peel is added, and the mixture is heated to 80°C and stirred at 80 rpm for 2.5 hours. After cooling to 40°C, the mixture is filtered. A 2.0wt% hydrogen peroxide solution with a concentration of 2 times the weight of the filter residue (the pH is adjusted to 10.5 with sodium hydroxide) is added to the filter residue, and the mixture is heated to 50°C and stirred at 100 rpm for 2 hours. After cooling to 40°C, the mixture is filtered. Water is added to the filter residue to dilute it to a solid content of 7.5wt%. The mixture is then ground in a colloid mill for 12 minutes (with a gap of 80 μm) to obtain the ground material. The mixture is centrifuged at 10,000 rpm for 10 minutes. The centrifuged precipitate is washed with water 3 times (this process can be combined with multiple centrifugation and washing processes to check whether the residues of sodium hydroxide, hydrogen peroxide, citric acid, etc., meet food safety requirements; the same applies below). The washed solids are freeze-dried to a water content of 3.76wt% to obtain the grapefruit peel derivative. Comparative Example 5: Compared to Example 1, the pH of the filtrate in step 1 was adjusted to 6.8 using sodium hydroxide, while the rest remained the same.

[0042] Comparative Example 6: Compared to Example 1, the 3 wt% whey protein solution was replaced with a 3 wt% sodium alginate solution, and everything else remained the same.

[0043] Comparative Example 7: Compared to Example 1, in step 3, no suspension was used, the composite particulate material was replaced with a dispersion containing 3 wt% derivative, and in step 4, a dispersion containing 3 wt% derivative, equal to one times the weight of the initial sauce, was added to the initial sauce. All other aspects were the same.

[0044] Comparative Example 8: Compared to Example 1, in step 3, a dispersion with a derivative content of 3 wt% was not used, and a suspension was used instead of composite particulate material. In step 4, a suspension with a weight of 1 times that of the initial sauce was added to the initial sauce. All other aspects were the same.

[0045] Comparative Example 9: Compared to Example 1, tea polyphenols were not added in step 3, but everything else was the same.

[0046] Comparative Example 10: Compared to Example 1, in step 2: Wasabi rhizomes and leaves were cut into pieces (approximately 1 cm in length, width, and height), mixed with grapefruit juice, added to a colloid mill and ground at room temperature for 12 minutes (80 μm gap) to obtain ground material, grapefruit oil was added and homogenized at room temperature (500 bar) for 5 minutes to obtain the initial sauce.

[0047] The sauces from the above embodiments and comparative examples were tested to determine the isothiocyanate content in the prepared sauces and the isothiocyanate content after storage. The test steps are as follows: To plot the standard curve: Take different volumes (e.g., 0, 0.1, 0.3, 0.5, 0.8, 1, 2, 3 mL) of standard solution (1 g / L allyl isothiocyanate in dichloromethane), add dichloromethane to make up to 10 mL, shake well, and then measure the absorbance at a wavelength of 249 nm (where isothiocyanate has the maximum absorption). Plot the concentration on the x-axis and the absorbance on the y-axis to obtain the standard curve. Isothiocyanate content determination: 10g of wasabi paste prepared in the examples and comparative examples (0 days, 90 days stored at 25℃ in the dark, and 180 days stored at 25℃ in the dark) were placed in a stirring container. 100mL of disodium hydrogen phosphate-citric acid buffer solution (pH 7.0) was added, followed by L-ascorbic acid to a final concentration of 0.15mg / mL. After enzymatic hydrolysis in a sealed water bath at 45℃ for 1.5h, 750mL of dichloromethane was added, and the mixture was sonicated at 25℃ for 15min. The mixture was then filtered under reduced pressure. The filtrate was allowed to stand at 20℃ for 1 hour, and the lower layer was separated. The absorbance at 249nm was measured. The isothiocyanate content in the wasabi paste was calculated based on the absorbance value. The retention rate of isothiocyanates was calculated by converting the content at different storage days under room temperature conditions. The results are shown in Table 1.

[0048] Table 1: Isothiocyanate content in wasabi paste treated at room temperature

[0049] In addition, this invention also tested the preservation effect of isothiocyanates after low-temperature storage. The test steps are as follows: 10g of wasabi paste prepared in the examples and comparative examples were taken respectively, and the isothiocyanate content in the wasabi paste after 0 days and after 180 days of refrigeration at 4℃ was tested. The test method is as follows: the wasabi paste was placed in a stirring container, 100mL of disodium hydrogen phosphate-citric acid buffer solution with pH 7.0 was added, and then L-ascorbic acid was added to 0.15mg / mL. After enzymatic hydrolysis in a sealed water bath at 45℃ for 1.5h, 750mL of dichloromethane was added, and the mixture was sonicated at 25℃ for 15min. Then, the mixture was filtered under reduced pressure, and the filtrate was allowed to stand at 20℃ for 1 hour before separation. The absorbance value of the lower layer was measured at a wavelength of 249nm. The isothiocyanate content in the wasabi paste was calculated based on the absorbance value. The retention rate of isothiocyanates was obtained by converting the content at different storage days. The results are shown in Table 2.

[0050] Table 2: Isothiocyanate content in refrigerated wasabi paste

[0051] According to the test results in the table, the wasabi paste prepared by this invention can retain a large amount of isothiocyanate. The loss rate of isothiocyanate during the preparation process is low, and the retention rate of isothiocyanate is high after 90 and 180 days of storage at room temperature and low temperature. Among them, the storage of wasabi paste at room temperature and low temperature is challenging, but the wasabi paste prepared by this invention still retains a high content of isothiocyanate. The process of this invention has a great effect on improving the storage capacity of wasabi paste at room temperature.

[0052] Comparative Example 1 added a pasteurization process at 75°C for 20 seconds after filling, while everything else remained the same. Example 1, however, did not require sterilization during preparation. The absence of this heat treatment process improved the wasabi paste's ability to retain effective isothiocyanate content, particularly during room temperature storage.

[0053] In Comparative Example 2, omitting the grapefruit oil from Example 1 reduced the ITCs content at day 0 from 485.79 mg / kg to 453.47 mg / kg, and the retention rate at day 180 from 89.86% to 46.15%. Grapefruit oil can reduce the loss rate of ITCs during preparation and also reduce the loss rate during storage.

[0054] In Comparative Example 3, gum arabic was used instead of grapefruit peel derivatives, resulting in a decrease in ITCs content from 485.79 mg / kg to 459.04 mg / kg at day 0, and a decrease in retention rate from 89.86% to 55.31% after 180 days of storage at room temperature. The grapefruit peel derivatives prepared in this invention possess a rigid structure and high crystallinity, forming a dense interparticle film at the oil-water interface, exhibiting extremely high mechanical strength and resistance to aggregation and agglomeration, as well as high barrier properties against oxygen and moisture. After citric acid treatment, the surface carboxyl groups of the grapefruit peel derivatives are protonated under acidic conditions, generating electrostatic attraction and hydrogen bonding with positively charged whey protein. Simultaneously, the phenolic hydroxyl groups of tea polyphenols form a multiple hydrogen bond network with the surfaces of whey protein and cellulose, and the three components self-assemble to form a stable composite particle structure. These composite particles are enriched at the oil-water interface, allowing the antioxidant activity of tea polyphenols to be fully utilized, further inhibiting the oxidative degradation of isothiocyanates and improving system stability. In contrast, Comparative Example 3 used gum arabic, which resulted in poor system stability. During storage, oil droplets tended to coalesce, reducing the interfacial area and increasing the proportion of isothiocyanates exposed to the aqueous phase and oxygen. Consequently, the retention rates at 90 and 180 days were significantly lower than those in Example 1.

[0055] In the preparation of grapefruit peel derivatives in Comparative Example 4, the citric acid solution treatment was omitted, which reduced the ITCs content at day 0 from 485.79 mg / kg to 446.35 mg / kg, and the retention rate after 180 days of storage at room temperature from 89.86% to 61.05%.

[0056] Comparative Example 5 grapefruit juice had a pH of 6.8, which is outside the 3.5-4 range of this invention. This resulted in a lower efficiency in inhibiting the formation of ITCs from glucosinolate substrates during the wasabi paste preparation process, leading to significant ITC loss during the preparation. Since a large amount of glucosinolate substrates had already been consumed in the previous processing, the ability to generate ITCs during the later storage process was reduced, and the ITC content obtained after storage was also lower.

[0057] Comparative Example 6 did not use whey protein, while in Example 1, whey protein and tea polyphenols self-assembled to form a tea polyphenol-whey protein complex with an amphiphilic structure. Whey protein provided hydrophobic regions and charged residues, while tea polyphenols provided antioxidant activity and additional hydrogen bond binding sites. In contrast, the sodium alginate-tea polyphenol complex and the grapefruit peel derivative existed independently and could not be synergistically anchored at the oil-water interface, resulting in low interfacial adsorption rate and poor interfacial film density. At the same time, sodium alginate lacked the hydrophobic regions of whey protein and had weak affinity for the oil-water interface, further weakening the interfacial protection effect and thus reducing the retention rate of ITCs.

[0058] Comparative Example 7 used only a dispersion containing grapefruit peel derivatives without using the composite particulate material containing whey protein-tea polyphenols; Comparative Example 8 used only a suspension containing whey protein-tea polyphenols without using a dispersion containing grapefruit peel derivatives. The tested ITCs and retention rates decreased. The tea polyphenols in the composite particulate material have extremely strong free radical scavenging capabilities. After accumulating at the oil-water interface, they block the reaction and inactivation of isothiocyanates. The presence of whey protein enhances the adsorption of grapefruit peel derivatives at the interface and provides a better amphiphilic balance on the surface of the composite particles. The rigid structure of the grapefruit peel derivatives forms a dense, interlocking film at the oil-water interface, providing a high-strength physical barrier, stabilizing the system and inhibiting the decomposition of ITCs. A comparison of Comparative Examples 7-8 with Example 1 shows that the optimal effect is achieved by combining the dispersion containing grapefruit peel derivatives with the composite particulate material containing whey protein-tea polyphenols, exhibiting a synergistic effect in inhibiting ITC inactivation and retaining ITC content after storage.

[0059] Comparative Example 9 lacked tea polyphenols, and the grinding at room temperature in Comparative Example 10 reduced the content of ITCs in the finished product, and the retention rate of ITCs also decreased after storage.

[0060] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A method for preparing grapefruit wasabi jam, characterized in that, Includes the following steps: Step 1: Juice the grapefruit pulp and adjust the pH to obtain grapefruit juice; press the grapefruit seeds to obtain grapefruit oil; pulp the grapefruit peel, add sodium hydroxide solution for treatment, filter, add hydrogen peroxide solution to the filter residue, filter again, add water to the filter residue, grind, concentrate and add citric acid solution for treatment, centrifuge, wash and dry to obtain grapefruit peel derivatives; Step 2: Cut the wasabi root and leaves into pieces, mix with grapefruit juice, pre-cool, grind to obtain a ground mixture, add grapefruit oil and homogenize to obtain the initial sauce; Step 3: Adjust the pH of the whey protein solution, add tea polyphenols, and disperse to obtain a suspension; take grapefruit peel derivatives and disperse them in water to obtain a dispersion, mix with the suspension, adjust the pH again, stir, and obtain composite particulate material; Step 4: Add compound granular material to the initial sauce and disperse to obtain a semi-finished product; then add granular wasabi, salt, sweetener and grapefruit pulp, stir, and fill to obtain grapefruit wasabi sauce.

2. The preparation method according to claim 1, characterized in that, The pH of grapefruit juice is 3.5-4.

3. The preparation method according to claim 1, characterized in that, The temperature for precooling, grinding and homogenization in step 2 is 1-6℃.

4. The preparation method according to claim 1, characterized in that, In step 3, the pH of the whey protein solution is adjusted to 7.5-8.5, and then adjusted again to 3.7-4.

2.

5. The preparation method according to claim 1, characterized in that, In step 1, the sodium hydroxide solution treatment involves adding a 3-6 wt% sodium hydroxide solution and heating and stirring for 1-4 hours; the hydrogen peroxide solution treatment involves adding a 1.5-5 wt% alkaline hydrogen peroxide solution and heating and stirring for 1-4 hours; and the citric acid solution treatment involves adding a 45-55 wt% citric acid aqueous solution and hydrothermally reacting for 0.5-2.5 hours.

6. The preparation method according to claim 1, characterized in that, In step 2, the weight ratio of wasabi root, leaves, grapefruit juice and grapefruit oil is 1:(0.5-1):(1-2):(0.25-0.4).

7. The preparation method according to claim 1, characterized in that, In step 3, the weight ratio of whey protein, tea polyphenols, and grapefruit peel derivatives is (1.2-1.7):(0.25-0.35):(3-5).

8. The preparation method according to claim 1, characterized in that, In step 4, the amount of compound granular material added is 0.85-1.1 times the weight of the initial sauce.

9. The preparation method according to claim 1, characterized in that, In step 4, the granular wasabi, salt, sweetener, and grapefruit pulp account for 5-20%, 3-8%, 0.001-5%, and 5-15% of the weight of the semi-finished product, respectively.

10. A grapefruit wasabi sauce prepared by the preparation method according to any one of claims 1-9.

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