Eutectic solvent for decrystallization of honey of various flowers as well as preparation method and application of eutectic solvent

Abstract

The invention belongs to the technical field of eutecticevaporate solvent application, and particularly relates to an eutecticevaporate solvent for decrystallization of honey of various flowers as well as a preparation method and application of the eutecticevaporate solvent. The eutectic solvent is composed of a hydrogen bond acceptor L-proline and a hydrogen bond donor L-ascorbic acid in a molar ratio of (16: 5)-(16: 7). The preparation method comprises the following steps: weighing L-proline and L-ascorbic acid in proportion, adding deionized water, and reacting at 55-70 DEG C for 1.5-2.5 hours; the invention also provides an application of the eutectic solvent in improving the crystal dissolution rate, the oxidation resistance and the sensory property of the honey and reducing the content of 5-HMF, the addition amount of the eutectic solvent is 1-15% of the mass of the honey, and the mixing temperature of the eutectic solvent and the honey is 35-45 DEG C. According to the method, the eutectic solvent in a specific ratio is used for regulating and modifying the honey of various flowers, the decrystallization rate of the honey of various flowers can be effectively increased, the quality index of the honey of various flowers can be improved, the operation is simple and convenient, and the method has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of eutectic solvent technology, specifically relating to a eutectic solvent for the decrystallization of multifloral honey, its preparation method, and its application. Background Technology

[0002] Liquid honey currently has a large market demand. However, in traditional decrystallization processes, especially those using heating methods, while the crystal content of honey can be reduced, the Maillard reaction is also promoted, leading to an increase in 5-hydroxymethylfurfural (5-HMF) content and affecting honey quality. Adjusting the fructose-to-glucose ratio in honey is a newer method, but this method requires strict control over the ratio; failure to do so may promote honey crystallization, and this method is difficult to promote and industrialize. Therefore, slowing down the quality deterioration of honey during the decrystallization process is one of the important solutions in the development of liquid honey preparation processes.

[0003] Current research on honey crystallization techniques has yielded numerous studies, but its shortcomings mainly lie in the following aspects: Currently, the main methods for decrystallizing honey are heating and adjusting the fructose-glucose ratio. Heating methods can be further divided into water bath heating, hot air heating, microwave heating, and ultrasonic methods. While these methods allow for continuous operation, their drawbacks include high temperatures that can easily damage the product, causing the loss of bioactive components. Secondly, the 5-HMF content in liquid honey prepared through heating increases, resulting in a loss of honey quality. Finally, heat processing methods suffer from uneven heating, low heat transfer efficiency, and poor temperature controllability, affecting the application effects of liquid honey products. Based on the fructose-glucose ratio, honey can be classified into three categories: rapid crystallization (fructose-glucose < 1.11), medium-speed crystallization (1.11 < fructose-glucose < 1.33), and slow crystallization (fructose-glucose > 1.33). Adjusting the fructose-glucose ratio achieves decrystallization by regulating the ratio between the two. The disadvantages of this method are that the wide variety of honey types makes it difficult to control the fructose-glucose ratio, and it requires strict operation. An imbalance in the ratio can actually promote crystallization, thus hindering its widespread adoption and industrial application. Therefore, this invention introduces a low eutectic solvent (DESs) into honey to prepare liquid honey. The heating temperature is relatively low, which reduces the impact of heat on honey quality, avoids complicated operations, and produces a liquid honey product with good quality and high crystallization rate.

[0004] There are generally two processes for decrystallizing honey using heating methods (see appendix). Figure 1) The first type: According to the research of Peláez-Acero et al. (Peláez-Acero A, Cobos-Velasco JE, González-Lemus U, etal. Bioactive compounds and antibacterial activities in crystallized honeyliquefied with ultrasound[J]. Ultrasonics Sonochemistry, 2021, 76: 105619;Kabbani D, Sepulcare F, Wedekind J. Ultrasound-assisted liquefaction ofrosemary honey: Influence on rheology and crystal content[J]. Journal of FoodEngineering, 2011, 107(2): 173-178; Pasias IN, Raptopoulou KG, MakrigennisG, et al. Finding the optimum treatment procedure to delay honeycrystallization without reducing its quality[J]. Food chemistry, 2022, 381:132301; Dżugan M, Grabek-Lejko D, Sidor E, et al. The impact of ultrasounddecrystallization on enzymatic, antioxidant and antibacterial properties of honey[J]. Innovative food science & emerging technologies, 2021, 71: 102709; Xu Sijia, Luo Shiye, Wang Chaoli, et al. Effect of ultrasound decrystallization on the physicochemical properties of loquat honey[J]. Food Science, 2025, 46(13): 292-303; Fang Chongwei. Effect of heating decrystallization on the antibacterial activity of honey[J]. Bee Journal, 2022, 42(02): 10-12; Liu Ning, Li Chenchen, Song Xiuchao, et al. Optimization of decrystallization technology for Northeast black bee linden honey[J]. Food Science, 2014, 35(22): 68-72.The Chinese patents filed regarding the heating and crystallization of honey, namely "An Energy-Saving Honey Crystallization Device" (Patent No.: 202423010867.3), "A Method and Device for Honey Crystallization" (Patent No.: 202210265615.1), and "A Honey Crystallization Heating Equipment" (Patent No.: 202321221706.1), directly heat the honey to achieve crystallization. The advantage of this preparation method is that it is fast and convenient. The disadvantage is that heating promotes the occurrence of the Merahedral reaction in honey and increases its reaction rate, resulting in an increase in the 5-HMF content in the final product. The second method, based on the research of Amariei Sonia et al. (Amariei Sonia, Liliana Norocel, and Laura Agripina Scripcă. An innovative method for preventing honey crystallization. Innovative foodscience&emerging technologies, 2020, 66: 102481; Wang Hairong, Zhang Chuntao, Liang Wendong. Study on erythritol-honey co-crystallization and its co-crystallization process [J]. China Food Additives, 2016, (11): 88-93.), involves adjusting the ratio of fructose to glucose to reduce crystallization. While this method avoids the negative effects of heating, adjusting the ratio of fructose to glucose is difficult and requires strict control, making it difficult to promote and utilize widely.

[0005] DESs are mixtures of two or more substances whose melting points are significantly lower than the initial components. They can be used as solvents and even exist in liquid form at room temperature. DESs have been developed into a green solvent with characteristics of biocompatibility, recyclability, biodegradability, and low or non-toxicity (Zeba U, Minaxi S, Manikant T, et al. Biobased natural deep eutectic system as versatile solvents: Structure, interaction and advanced applications[J]. The Science of the total environment, 2023, 881: 163002). Related studies have shown that (Craveiro R, Rocha Â, Fernandes C, et al. Determination of mometasone furoate solubility, using deep eutectic systems, and topical formulation-experimental and computational studies[J]. Sustainable Chemistry and Pharmacy, 2024, 42: 101783.; Sharma, Anshu, et al. Deep eutectic solvents enhancing drug solubility and its delivery. Journal of Medicinal Chemistry 67.17 (2024): 14807-14819; Xue Ying, Cao Yejun, Wang Yinan, et al. Screening and efficacy evaluation of hydrochlorothiazide eutectic systems[J]. Central South Pharmacy, 2025, 23(12): 3564-3569.) DESs can significantly improve drug solubility and increase bioavailability, providing a safe and efficient technical path for the development of novel formulations. In the food industry, DESs have been used as extractants and cryoprotectants. Therefore, promoting the use of this novel green solvent is particularly important. DESs are typically composed of amino acids, organic acids, and sugars. Sugars can act as both hydrogen bond acceptors and donors, and honey, rich in sugars, is an excellent "container" for preparing DESs. This combination can achieve both increased honey crystallization rate and improved honey quality at lower temperatures, a process not yet documented in existing literature.This invention combines DESs with honey (see appendix). Figure 2 Improving the molar ratio between hydrogen bond donors and acceptors in the original honey system increases the binding of donors and acceptors, thereby improving the honey crystallization rate and producing honey with high antioxidant capacity and low 5-HMF, thus improving the quality of honey.

[0006] This invention selects L-proline and ascorbic acid as raw materials for the preparation of DESs. After adjusting their molar ratio, the two materials are fully combined under heating and stirring to form a eutectic solvent that remains liquid at room temperature. Amino acids and vitamins are widely used and safe food additives. L-proline and ascorbic acid have good solubility and can improve the quality and flavor of food. The L-proline and ascorbic acid used in this invention are both food-grade raw materials, reducing food safety risks. In addition, honey contains a large amount of fructose and glucose, both of which can be used as raw materials for the preparation of DESs. When DESs are introduced into honey, the molar ratio between the original system changes, which may cause fructose and glucose to combine with DESs, lowering the melting point and reducing the solid content, thereby increasing the honey crystallization rate. In this invention, the honey crystallization rate reaches about 90%.

[0007] Honey has a complex chemical composition and is rich in nutrients, containing sugars, organic acids, proteins, amino acids, vitamins, minerals, flavonoids, phenolic acids, and enzymes. It possesses a wide range of biological activities, including antioxidant, antibacterial, and anti-inflammatory properties, making it a natural functional food with significant development potential. Its biological activity is influenced by its plant source, geographical origin, processing methods, and storage conditions. Fructose and glucose are the main sugars in honey. Because glucose has low solubility in water and is prone to crystallization, glucose crystal formation during storage leads to honey crystallization, altering its physicochemical and sensory properties. Although crystallization is a natural phenomenon in honey, consumers have lower acceptance of crystallized honey, and it is also unfavorable for industrial processing and transportation. Therefore, decrystallization is a crucial step in the deep processing of honey to address the processing inconveniences and low consumer acceptance caused by crystallization. Summary of the Invention

[0008] This invention prepares a novel eutectic solvent (DESs) by mixing a specific hydrogen bond donor and a hydrogen bond acceptor in a certain molar ratio and heating and stirring, and applies it to the crystallization process of multifloral honey.

[0009] Firstly, this invention provides a eutectic solvent for the crystallization of multifloral honey. The eutectic solvent is composed of a hydrogen bond acceptor and a hydrogen bond donor. The hydrogen bond acceptor is L-proline, and the hydrogen bond donor is L-ascorbic acid. The molar ratio of L-proline to L-ascorbic acid is 16:5 to 16:7.

[0010] The eutectic solvent contains no more than 30% deionized water by mass and is prepared by heating and reacting at 55-70°C for 1.5-2.5 h.

[0011] The eutectic solvent is used to regulate the modified wildflower honey crystals and improve the crystallization rate of wildflower honey.

[0012] The eutectic solvent is used to reduce the 5-HMF content of wildflower honey and improve its antioxidant and sensory properties.

[0013] The amount of the eutectic solvent added is 1-15% of the honey by mass.

[0014] The present invention also provides a method for preparing a eutectic solvent for decrystallizing multifloral honey, characterized by comprising the following steps: weighing L-proline and L-ascorbic acid in a molar ratio of 16:5 to 16:7, adding no more than 30% deionized water, mixing, and heating the mixture at 55 to 70°C for 1.5 to 2.5 h to obtain a eutectic solvent with uniform color and no solids.

[0015] This invention provides a method for decrystallizing wildflower honey with a eutectic solvent, comprising the following steps: adding the eutectic solvent to wildflower honey at an addition amount of 1-15%, stirring evenly at 35-45°C to obtain a regulated modified wildflower honey crystal system. Beneficial effects

[0016] This invention presents a eutectic solvent prepared from proline and ascorbic acid. Its preparation process requires no complex chemical synthesis steps; a homogeneous and stable liquid system is formed simply by mixing proline and ascorbic acid in a specific molar ratio and stirring at a certain temperature. This eutectic solvent interacts with glucose molecules in honey through intermolecular forces such as hydrogen bonds and van der Waals forces, disrupting the ordered structure of glucose crystals and reducing crystal formation and growth. Simultaneously, it does not damage the original nutrients and bioactive substances of honey, effectively preserving its natural characteristics and health value. In practical applications, adding this eutectic solvent at a ratio of 2-10% to crystallized honey, with appropriate stirring and temperature control, can significantly improve the decrystallization rate to approximately 90%, while simultaneously reducing the 5-HMF content, greatly minimizing product losses caused by heating. The prepared liquid honey solves the problems of low acceptability, poor stability, poor taste, and high processing difficulty associated with crystallized honey; it maintains good fluidity and uniform texture, meeting the needs of subsequent processing and consumers.

[0017] Meanwhile, proline and ascorbic acid, as food-grade raw materials, avoid the potential health threats posed by chemical reagents. This eutectic solvent has widely available and low-cost raw materials, and its preparation process is simple, time-efficient, and requires no organic solvents or toxic chemicals, exhibiting excellent green and environmentally friendly characteristics that meet the safety and sustainability requirements of modern food processing. Furthermore, it exhibits excellent compatibility with honey, performing its de-crystallization function without introducing off-flavors or altering the original flavor characteristics of honey, further enhancing the quality and market competitiveness of the processed honey product.

[0018] This eutectic solvent can disrupt the structural stability of glucose crystals by forming hydrogen bonds with glucose molecules in honey, thereby effectively promoting the melting of crystallized honey. Experimental results show that under optimized process conditions, the crystallization rate of wildflower honey treated with this eutectic solvent can stably reach about 90%, and the retention rate of major nutrients in honey, such as sugars, vitamins, and phenolic acids, is high, avoiding the nutrient loss and quality degradation problems that may be caused by traditional crystallization methods. In addition, this eutectic solvent has the advantages of simple preparation process, low cost, and biodegradability, and has good application prospects in the field of honey processing.

[0019] This invention, by incorporating low-temperature technology, significantly reduces the negative impacts of product heating. It is a preferred novel food additive. As a functional component in the food industry, it has practical significance for people's health and well-being, and its future development prospects are promising. Attached Figure Description

[0020] Figure 1 Traditional honey crystallization process. Note: Although ultrasonic crystallization does not involve external heat application, the ultrasound generates a large amount of heat during the preparation process, which will also increase 5-HMF and affect the quality of honey. Therefore, the ultrasonic method is classified as a heating crystallization method.

[0021] Figure 2 This invention describes a process for preparing decrystalline honey using a eutectic solvent.

[0022] Figure 3 Images of multifloral honey prepared with different amounts of eutectic solvent. Note: From left to right, the samples in the images are CK group, DESs-2%, DESs-4%, DESs-6%, DESs-8%, and DESs-10%, respectively.

[0023] Figure 4 Polarized micrographs of wildflower honey prepared with different amounts of eutectic solvent.

[0024] Figure 5 Crystallization rate of wildflower honey prepared with different amounts of eutectic solvent. Note: The same letter in the same column indicates no significant difference.P ≥ 0.05); different letters in the same column's subheadings indicate significant differences ( P <0.05).

[0025] Figure 6 Antioxidant activity of wildflower honey prepared with different amounts of eutectic solvent. Note: Figure A represents DPPH scavenging ability; B represents ABTS scavenging ability; C represents ·OH scavenging ability. The same letter in the same column indicates no significant difference. P ≥0.05); different letters in the same column's shoulder labels indicate significant differences ( P <0.05).

[0026] Figure 7 Color of wildflower honey prepared with different amounts of eutectic solvent. Note: The same letter in the same column indicates no significant difference. P ≥ 0.05); different letters in the same column's subheadings indicate significant differences ( P <0.05).

[0027] Figure 8 The effect of different amounts of eutectic solvent added on the odor of wildflower honey. Note: Figure A shows the radar image of the electronic nose; Figure B shows the PCA analysis of the electronic nose.

[0028] Figure 9 : 5-HMF content of wildflower honey prepared with different amounts of eutectic solvent. Note: The same letter in the same column indicates no significant difference. P ≥ 0.05); different letters in the same column's shoulder labels indicate significant differences ( P <0.05).

[0029] Figure 10 Rheological properties of wildflower honey prepared with different amounts of eutectic solvent. Note: A represents viscosity; B represents storage modulus; C represents loss modulus.

[0030] Figure 11 FTIR images of wildflower honey prepared with different amounts of eutectic solvent.

[0031] Figure 12 Sensory scores of wildflower honey prepared with different amounts of eutectic solvent. Note: The same letter in the same column indicates no significant difference. P ≥ 0.05); different letters in the same column's subheadings indicate significant differences ( P <0.05).

[0032] Figure 13 Other amino acids cannot form a eutectic solvent with ascorbic acid (actual image).

[0033] Figure 14Table 1 shows the effect of different amounts of eutectic solvent added on the crystallization rate of wildflower honey crystals.

[0034] Figure 15 Table 2: Performance Description of Electronic Nose Sensor

[0035] Figure 16 Table 3. Sensory Evaluation Standards for Honey.

[0036] Figure 17 Table 4 shows whether different proportions of each substance form a eutectic solvent.

[0037] Figure 18 Table 5 shows the crystallization rate and sensory scores of wildflower honey with 10% eutectic solvent and the same amount of amino acids and ascorbic acid. Detailed Implementation

[0038] The following describes, in conjunction with embodiments, a method for controlling modified wildflower honey crystals using a eutectic solvent, as proposed in this invention.

[0039] In this embodiment, the multifloral honey is commercially available, and all other reagents are food-grade. Example 1

[0040] This embodiment takes commercially available multifloral honey as the research object and provides a low eutectic solvent suitable for the crystallization of multifloral honey.

[0041] Based on previous experiments, it was found that L-proline and L-ascorbic acid can form a eutectic solvent suitable for the crystallization of wildflower honey within a specific ratio range. Therefore, L-proline and L-ascorbic acid were selected to prepare a eutectic solvent for the low-temperature crystallization of natural wildflower honey.

[0042] According to preliminary experiments, the best results are achieved when hydrogen bond donors and hydrogen bond acceptors are mixed in a molar ratio of 16:5, that is, the molar ratio of hydrogen bond acceptors (amino acid substances) to hydrogen bond donors (organic acid substances) is 16:5.

[0043] The method for preparing the eutectic solvent used for the crystallization of wildflower honey is as follows.

[0044] ① Preparation of eutectic solvent: Based on the molar ratio of hydrogen bond acceptor (amino acid) to hydrogen bond donor (organic acid) of 16:5, L-proline and L-ascorbic acid were introduced, with the molar ratio of L-proline to L-ascorbic acid being 16:5. The calculated masses of L-proline and L-ascorbic acid were 1840 g and 880 g, respectively. 20% (w / w) deionized water (544 g) was added. L-proline, L-ascorbic acid and deionized water were mixed according to the above ratio and heated at a constant temperature of 60℃ for 2 h to obtain eutectic solvent, which finally formed a system with uniform color and no solids.

[0045] ② The prepared eutectic solvent was stirred uniformly with wildflower honey at 40℃ according to the mass ratio to ensure that the eutectic solvent and wildflower honey were fully combined and the system was homogeneous, thus obtaining a low-temperature regulated modified wildflower honey crystal system. The eutectic solvent was added at mass ratios of 2%, 4%, 6%, 8%, and 10% (w / w), respectively. Various indicators of the modified wildflower honey crystal system were measured, and the specific measurement methods are as follows.

[0046] a: Determination of crystallization rate and polarizing microscopy According to the method of Xu Sijia et al. (Xu Sijia, Luo Shiye, Wang Chaoli, et al. Effect of ultrasonic crystallization on the physicochemical properties of loquat honey [J]. Food Science, 2025, 46(13): 292-303.), the mixed sample was weighed into a centrifuge tube, centrifuged at 8000 r / min for 5 min at 25℃, the supernatant was taken and weighed, and the crystallization rate was calculated as follows:

[0047] To better visualize the effect of the eutectic solvent on the crystals of wildflower honey, a polarizing microscope (POM) was used to observe the crystal structure of the system. One to two drops of sample were added to a glass slide, covered with a coverslip, and the slide containing the sample was transferred to the stage. The field of view and focus were adjusted to obtain a clear image of the sample. Figure 3 , 4 5 and Table 1 ( Figure 14 As shown in the figure, with the continuous increase in the amount of DESs added, the crystal size of wildflower honey is continuously reduced and becomes smaller, the graininess of wildflower honey gradually decreases, and the crystallization rate also gradually increases. This proves the feasibility of using DESs to regulate honey crystals.

[0048] b: Determination of in vitro antioxidant activity According to Zhang et al. (Zhang Y, Xu M, Hu C, Liu A, Chen J, Gu C, Zhang (1):8918914; Cho KJ, Kim MU, Jeong GJ, Khan F, Jo DM, Kim Y M. Optimization of Protease Treatment Conditions for Chlorella pyrenoidosa Protein Extractionand Investigation of Its Potential as an Alternative Protein Source[J].Foods, 2024, 13(3):366.; He J, Dong Y, Liu X, et al. Comparison of chemical compositions, antioxidant, and anti-photoaging activities of Paeoniasuffruticosa flowers The method of determining DPPH, ABTS, and hydroxyl radical scavenging ability at different flowering stages[J]. Antioxidants, 2019, 8(9): 345.) was used.

[0049] DPPH: Take 0.1 mL of sample solution and 0.2 mL of 0.1 mmol / L DPPH working solution, mix well, and measure the absorbance at 517 nm at room temperature in the dark for 30 min. The DPPH calculation formula is as follows:

[0050] A0: Results obtained by replacing the sample group with ethanol; A: Results obtained by the experimental group; A1: Results obtained by replacing DPPH with ethanol.

[0051] ABTS: Prepare a mixture of 7 mmol / L ABTS solution and 2.45 mmol / L potassium persulfate solution, incubate at 25°C in the dark for 12 h, and dilute with PBS to a absorbance of 0.7 ± 0.05 at 734 nm before use. Mix 0.1 mL of the test solution with 2.9 mL of ABTS stock solution, incubate in the dark for 15 min, and measure the absorbance (A1) at 734 nm using a microplate reader. Use 0.1 mL of distilled water mixed with 2.9 mL of ABTS reagent and incubate in the dark for 15 min as a blank control (A). The ABTS calculation formula is as follows:

[0052] Hydroxyl radical scavenging capacity (·OH): Prepare 6 mmol / L FeSO4 solution, 6 mmol / L salicylic acid-ethanol solution, and 6 mmol / L H2O2 solution. Pipette 200 μL of the sample solution into a test tube, add 200 μL of 6 mmol / L FeSO4 solution and 200 μL of 6 mmol / L salicylic acid-ethanol solution sequentially, mix thoroughly, and then add 200 μL of 6 mmol / L H2O2 solution to initiate the reaction. After reacting in a water bath at 37℃ in the dark for 1 h, measure the absorbance at 510 nm using a microplate reader (A1). Replace the H2O2 solution with anhydrous ethanol and perform the same experimental procedure to measure the absorbance (A0). Replace the sample solution with anhydrous ethanol and perform the same experimental procedure to measure the absorbance (A2). Calculate the hydroxyl radical scavenging rate using the following formula:

[0053] In the formula: A1 is the absorbance of the sample group; A2 is the absorbance of the blank control; A0 is the background absorbance of the sample.

[0054] from Figure 6 The addition of DESs can significantly improve the antioxidant capacity of wildflower honey, likely because DESs contains L-ascorbic acid. L-ascorbic acid is a natural antioxidant with strong reducing power. This enhanced antioxidant activity indicates that DESs can not only regulate the crystal structure of honey but also improve its physicochemical properties.

[0055] c: Determination of color and odor The color of the samples was determined using a colorimeter according to the method described by Zhang et al. (Zhang L, Yu Y, Wen Q, et al. Decoding the effects of brining time on the sensory quality, physicochemical properties and flavor characteristics of marinated grass carp meat[J]. Food Chemistry: X, 2025, 25:102081.). Odor was determined using an electronic nose; specific parameters are shown in Table 2. Figure 15 ).

[0056] Accurately weigh 3 g of sample into a headspace vial and seal the vial. Washing time: 120 s, detection time: 100 s, internal flow rate: 400 mL / min, injection flow rate: 400 mL / min. Select the values ​​corresponding to 10 time points where the response value is stable and take the average. From... Figure 6 As can be seen, the addition of DESs can significantly improve the color of wildflower honey.

[0057] The color of honey is primarily determined by its plant origin, but also depends on its ash content and the temperature and storage time it spends in the beehive. Figure 7 As shown, different amounts of DESs added significantly affect the color of honey, increasing the brightness of multifloral honey. For example... Figure 8 As shown in Figure A, the flavor characteristics of each sample were analyzed using an electronic nose to determine the contribution rate of each flavor. It was found that the addition of DESs primarily affected the S2 (nitrogen oxides), S6 (methyl compounds), S7 (sulfides), S8 (alcohols and aldehydes / ketones), and S9 (organosulfur compounds) sensors within the honey system, indicating that different amounts of DESs alter the volatile compounds in honey. Figure 8 As shown in B, PC1 contributes 91.78% of the variance, PC2 contributes 5.98%, and the cumulative variance contribution is 97.76%.

[0058] Determination of d:5-HMF Following a slight modification of the method described by Zhu et al. (Zhu Y, Lv H, Jiang M, et al. Effect of dual-frequency ultrasonic vacuum drying on drying characteristics and quality of honey[J]. LWT, 2024, 213: 117071.), the sample and standard solutions were first filtered through a 0.22 μm organic membrane. Separation was then performed on a Waters UHPLC (I-Class, Waters US) column equipped with an Eclipse Plus-C18 (2.1 × 100 mm 1.8-Micron) and analyzed at 284 nm. The column temperature was 35℃; the injection volume was 10 μL; the mobile phase was 90% ultrapure water + 10% methanol; and the flow rate was 1.00 mL / min. A standard curve was plotted with the concentration (μg / mL) of the 5-HMF standard on the x-axis and the peak area on the y-axis.

[0059] like Figure 9 As shown, the 5-HMF content in honey with added DESs was significantly lower than that in the control group (CK), and far below the levels stipulated in Codex Alimentarius and GH / T 18796-2012. This indicates that DESs crystallization did not promote the accumulation of 5-HMF, avoiding the drawbacks of increased 5-HMF content after traditional heating and ultrasonic crystallization. Compared to traditional heating and ultrasonic crystallization, the decrease in 5-HMF under this method may be due to the lower crystallization temperature and the improved antioxidant capacity of the honey.

[0060] e: Determination of rheological properties According to the method of Zhang Fuqiang et al. (Zhang Fuqiang, Bao Qichang, Chen Maoshen. Effect of syrup addition on rheological behavior of jujube honey [J] Food Industry, 2024, 45(3): 151-155), an appropriate amount of the mixed sample was placed in a rheometer for equilibration for 2 min. A rotor with a radius of 40 mm was selected, and the rheological behavior of the sample was measured at 25℃ in the range of 1 to 100 s. -1 Viscosity within the shear rate range. The storage modulus (G) and loss modulus (G") of the samples were determined under the conditions of a strain level of 2%, a frequency of 0.1 to 10 Hz, and a temperature of 25 °C.

[0061] The viscosity of the control group (CK) decreased with increasing shear rate and eventually remained constant. However, the viscosity of the honey remained almost unchanged after the addition of DESs. This indicates that DESs alters the rheological properties of honey by reducing crystal content. Figure 10As shown in B and C, the loss modulus (G") of all samples is greater than the storage modulus (G'), indicating that the honey exhibits strong viscosity. Honey is reported to be a typical viscous fluid (G > G'), and increased temperature increases its fluidity. As crystallization proceeds, the loss modulus decreases significantly, indicating that crystallization significantly reduces the content of solid crystals, causing the honey to exhibit liquid-like (viscous) behavior. Furthermore, the honey in the DESs-added group has lower G" and G' values ​​than the CK group.

[0062] f: Fourier transform infrared determination The attenuated total internal reflection (ATR) method was used for testing, with a scanning range of 4000 ~ 400 cm. -1 Spectral resolution of 4 cm -1 Infrared spectra of all samples were acquired at room temperature. Background correction was performed using signals from pure KBr pellets before each acquisition. Data were processed using OMNIC™ software after acquisition.

[0063] from Figure 11 Adding DESs to honey slightly alters the positions of chemical bonds, further illustrating the binding between honey and DESs. This bond shift may be due to a resetting of the hydrogen bond network within the system. The vibrational frequency shift to lower wavenumbers indicates that more hydrogen bonds have formed between DESs and honey.

[0064] g: Sensory evaluation Sensory evaluation was conducted according to the method described by Nikolova et al. (Nikolova YA, Vangelova VD, Balev D, et al. Comparative Study of Bulgarian Linden Honey (Tilia sp.)[J]. Foods, 2025, 14(2): 175-175.). Ten food science students were selected and their sensory evaluations were performed according to Table 3. Figure 16 The scoring criteria for honey are based on sensory evaluation. Each sample must be rinsed with warm water before evaluation, and no communication is allowed among the participants to ensure the independence of the scoring process.

[0065] like Figure 12 As shown, adding DESs can improve the sensory score of honey, but the sensory score decreases as the amount added increases. This may be because the addition of DESs reduces the graininess and color of wildflower honey, thus altering the sensory score. Comparative Example

[0066] First, the inventors tested various amino acids (glycine, arginine, glutamic acid, etc.) and ascorbic acid, citric acid, etc., in molar ratios to prepare eutectic solvents, but none of them could form a eutectic solvent. (See...) Figure 13 Table 4 ( Figure 17 As shown in the diagram. Because citric acid alters the flavor of honey, wildflower honey exhibits a noticeable sour taste after adding citric acid to a eutectic solvent, severely affecting its flavor. Therefore, citric acid cannot be used to prepare eutectic solvents.

[0067] Subsequently, the inventors directly calculated the corresponding weights of various amino acids and ascorbic acid in a molar ratio of 16:5, and added them to commercially available wildflower honey (without forming a eutectic solvent) at a mass ratio of 10%. The mixture was stirred evenly with the wildflower honey at 40°C until fully mixed and homogeneous. The crystallization rate and sensory score of the wildflower honey were then measured, as shown in Table 5. Figure 18 As shown in the figure.

[0068] Example 2

[0069] This embodiment takes commercially available multifloral honey as the research object and provides a low eutectic solvent suitable for the crystallization of multifloral honey.

[0070] In this embodiment, the hydrogen bond donor and the hydrogen bond acceptor are mixed in a molar ratio of 16:7, that is, the molar ratio of hydrogen bond acceptor (L-proline) to hydrogen bond donor (L-ascorbic acid) is 16:7.

[0071] The method for preparing the eutectic solvent used for the crystallization of wildflower honey is as follows.

[0072] ① Preparation of eutectic solvent: Based on the molar ratio of hydrogen bond acceptor (amino acid) to hydrogen bond donor (organic acid) of 16:7, L-proline and L-ascorbic acid were introduced, with the molar ratio of L-proline to L-ascorbic acid being 16:7. The calculated masses of L-proline and L-ascorbic acid were 1840 g and 1232 g, respectively. 30% (w / w) of deionized water (921.6 g) was added. L-proline, L-ascorbic acid and deionized water were mixed according to the above ratio and heated at a constant temperature of 55℃ for 2.5 h to obtain eutectic solvent, finally forming a system with uniform color and no solids.

[0073] ② The prepared eutectic solvent was mixed with wildflower honey at a mass ratio of 15% (w / w) and stirred evenly at 35°C to ensure that the eutectic solvent and wildflower honey were fully combined and the system was homogeneous, thus obtaining a low-temperature regulated modified wildflower honey crystal system.

[0074] The multifloral honey produced in this embodiment achieved a crystallization rate of 94.61%; a 5-HMF content of 7.48 μg / mL; and a sensory score of 70.80. Example 3

[0075] This embodiment takes commercially available multifloral honey as the research object and provides a low eutectic solvent suitable for the crystallization of multifloral honey.

[0076] In this embodiment, the hydrogen bond donor and the hydrogen bond acceptor are mixed in a molar ratio of 16:6, that is, the molar ratio of hydrogen bond acceptor (L-proline) to hydrogen bond donor (L-ascorbic acid) is 16:6.

[0077] The method for preparing the eutectic solvent used for the crystallization of wildflower honey is as follows.

[0078] ① Preparation of eutectic solvent: Based on the molar ratio of hydrogen bond acceptor (amino acid) to hydrogen bond donor (organic acid) of 16:6, L-proline and L-ascorbic acid were introduced, with the molar ratio of L-proline to L-ascorbic acid being 16:6. The calculated masses of L-proline and L-ascorbic acid were 1840 g and 1056 g, respectively. 10% (w / w) of deionized water (289.6 g) was added. L-proline, L-ascorbic acid and deionized water were mixed according to the above ratio and heated at a constant temperature of 70℃ for 1.5 h to obtain eutectic solvent, which finally formed a system with uniform color and no solids.

[0079] ② The prepared eutectic solvent was mixed with wildflower honey at a mass ratio of 1% (w / w) and stirred uniformly at 45℃ to ensure that the eutectic solvent and wildflower honey were fully combined and the system was homogeneous, thus obtaining a low-temperature regulated modified wildflower honey crystal system.

[0080] The multifloral honey produced in this embodiment achieved a crystallization rate of 68.31%; a 5-HMF content of 8.91 μg / mL; and a sensory score of 69.40.

Claims

1. A eutectic solvent for the decrystallization of multifloral honey, characterized in that, The eutectic solvent is composed of a hydrogen bond acceptor and a hydrogen bond donor, wherein the hydrogen bond acceptor is L-proline and the hydrogen bond donor is L-ascorbic acid, and the molar ratio of L-proline to L-ascorbic acid is 16:5 to 16:

7.

2. The eutectic solvent for multifloral honey crystallization according to claim 1, characterized in that, The eutectic solvent also contains no more than 30% deionized water by mass, and is prepared by heating and reacting at 55-70°C for 1.5-2.5 h.

3. The application of the eutectic solvent of claim 1 for the crystallization of multifloral honey, characterized in that, The eutectic solvent is used to regulate the crystals of modified wildflower honey and improve the crystallization rate of wildflower honey.

4. The application of the eutectic solvent of claim 1 for the crystallization of multifloral honey, characterized in that, The eutectic solvent is used to reduce the 5-HMF content of wildflower honey, thereby improving its antioxidant properties and sensory characteristics.

5. The application of the eutectic solvent for the crystallization of multifloral honey according to claim 3 or 4, characterized in that, The amount of the eutectic solvent added is 1-15% of the honey by mass.

6. A method for preparing a eutectic solvent for the decrystallization of multifloral honey as described in claim 1 or 2, characterized in that, Includes the following steps: Weigh L-proline and L-ascorbic acid in a molar ratio of 16:5 to 16:7, add no more than 30% deionized water, mix, and heat at 55 to 70°C for 1.5 to 2.5 h to obtain a eutectic solvent with uniform color and no solids.

7. A method for decrystallizing wildflower honey using the eutectic solvent according to any one of claims 1 to 3, characterized in that, Includes the following steps: The eutectic solvent was added to wildflower honey at an amount of 1-15%, and stirred evenly at 35-45°C to obtain a regulated modified wildflower honey crystal system.

Images