Preparation method of durian nectar and durian nectar

Abstract

The application relates to the technical field of preparation of durian milk, and provides a preparation method of durian milk, which comprises the following steps: S1, raw material treatment: durian pulp is soaked in a low-temperature aqueous solution of bamboo leaf extract and chlorogenic acid; S2, microwave treatment: the soaked durian pulp is subjected to intermittent microwave heating until the pulp is softened to obtain durian paste; S3, shearing homogenization: water, lemon balm leaves, milk and sugar are added into the durian paste after the microwave treatment, the moisture is adjusted, shearing beating is carried out, and then high-pressure homogenization is carried out on the slurry; and S4, sterilization: the slurry after the homogenization is subjected to ultra-high temperature instant sterilization treatment. Based on the method, the browning of durian can be reduced, the core flavor can be reserved, and the taste of the durian milk can be improved. In addition, the application further provides durian milk.

Description

Technical Field

[0001] This invention relates to the field of durian syrup preparation technology, specifically to a method for preparing durian syrup and the durian syrup itself. Background Technology

[0002] In recent years, in addition to being sold as a single product, the durian deep-processing industry has also shown a diversified development trend, forming three major categories: ready-to-eat fruit pulp products, frozen prepared products, and canned desserts. Among them, durian sago has become a popular dessert category due to its scenario-based and youth-oriented transformation.

[0003] The unique flavor of durian is primarily determined by the interaction of sulfur-containing compounds and ester compounds. Some esters contribute a prominent sweet aroma, while sulfides are associated with characteristic odors. This creates a unique flavor balance during processing.

[0004] In industrial production, durian syrup needs to be sterilized at high temperatures to meet commercial sterility requirements, but this brings significant technical challenges: high temperatures can exacerbate enzymatic browning, leading to deterioration of the pulp color and degradation of heat-sensitive nutrients; at the same time, it can cause a large amount of key volatile flavor substances to escape, weakening the product's aroma; ultimately affecting the product's nutrition and flavor.

[0005] Therefore, this application studies a method for preparing durian syrup that reduces browning of durian, preserves the core flavor, and improves the taste of durian syrup. Summary of the Invention

[0006] To reduce browning of durian, preserve its core flavor, and improve the taste of durian syrup.

[0007] This application provides a method for preparing durian syrup, which adopts the following technical solution:

[0008] A method for preparing durian syrup includes the following steps:

[0009] S1: Raw material processing: Soak durian pulp in a low-temperature aqueous solution containing a mixture of bamboo leaf extract and chlorogenic acid;

[0010] S2: Microwave treatment: Intermittently microwave the soaked durian pulp until it softens to obtain durian puree;

[0011] S3: Shearing and homogenization: Add water, lemon peach leaves, milk and sugar to the microwave-treated durian puree, adjust the moisture content and shear and beat the puree, then homogenize the puree under high pressure.

[0012] S4: Sterilization: The homogenized slurry is subjected to ultra-high temperature instantaneous sterilization treatment.

[0013] By employing the above-mentioned technical solutions, combining pretreatment with bamboo leaf extract and chlorogenic acid with ultra-high temperature instantaneous sterilization, enzymatic reactions are blocked during pretreatment, and heat exposure time is shortened during posttreatment. The synergistic effect of these two processes effectively inhibits both enzymatic and non-enzymatic browning, thereby reducing durian browning and improving the color stability of durian pudding. Microwave treatment enables rapid and uniform heating, reducing the thermal decomposition time of flavor substances. Ultra-high temperature instantaneous sterilization greatly shortens the high-temperature treatment time. The combined effect of these two processes minimizes the loss and destruction of volatile aroma compounds, such as esters, allowing durian pudding to retain its rich, characteristic durian flavor. Shearing and high-pressure homogenization thoroughly break down the pulp fibers, forming a uniform and stable emulsion system, resulting in a smooth and delicate texture for durian pudding, avoiding graininess and layering sedimentation, and improving taste quality. The interconnected and mutually reinforcing steps reduce durian browning, preserve the core flavor, and enhance the taste of durian pudding.

[0014] Optionally, in step S1, the low-temperature aqueous solution containing the mixture of bamboo leaf extract and chlorogenic acid includes bamboo leaf extract with a mass concentration of 0.1%-0.3% and chlorogenic acid with a mass concentration of 0.1%-0.3%.

[0015] By employing the above-mentioned technical solutions, bamboo leaf extract scavenge free radicals through flavonoids, blocking the lipid peroxidation chain reaction and reducing oxidative damage to biomolecules (such as DNA and proteins). Ketones, lactones, and phenolic acids in bamboo leaf extract can also react with quinone intermediates to form colorless complexes, blocking the browning chain reaction, reducing lipid oxidation levels, and decreasing the formation of oxidation products such as malondialdehyde (MDA). Chlorogenic acid can form hydroxyl radicals with antioxidant properties, effectively scavenging reactive oxygen species such as superoxide anions and hydroxyl radicals, reducing oxidative stress damage to cells, and competitively inhibiting polyphenol oxidase activity, reducing the binding of enzymes to natural substrates, thereby blocking enzymatic browning reactions.

[0016] Flavonoid glycosides (such as scutellarin and isoscutellarin) in bamboo leaf extract scavenge free radicals through electron transfer or hydrogen atom donation, blocking the chain reaction of aliphatic chain auto-oxidation. The combination of the two can significantly enhance the scavenging ability against superoxide anions and hydroxyl radicals. Thus, by utilizing the synergistic antioxidant and enzyme inhibitory effects of bamboo leaf extract and chlorogenic acid, a dual blockade against the oxidation of phenolic substances is formed in the pretreatment stage.

[0017] Optionally, in step S1, the soaking is carried out at 4°C for 15 minutes.

[0018] By adopting the above technical solutions, the browning reaction is reduced by inhibiting the reproduction of microorganisms and slowing down the activity of enzymes such as polyphenol oxidase. At the same time, the molecular thermal motion is reduced to slow down the oxidation process, thereby maintaining the stability of active ingredients and reducing the softening of durian chunks and loss of flavor. Ultimately, multiple preservation effects are achieved, such as extending shelf life and maintaining color and taste.

[0019] Optionally, in step S2, the power of the intermittent microwave heating is 500W, and the specific operation includes: heating for 1 minute, then taking it out and stirring, then heating for another 30 seconds, and repeating this cycle 2-3 times.

[0020] By adopting the above technical solution, the intermittent microwave heating process utilizes the unique interaction between high-frequency electromagnetic waves and the polar molecules of food, with its thermal and non-thermal effects working synergistically to achieve multiple goals of heating, sterilization, and flavor optimization. Unlike traditional surface heating methods such as steaming and baking, microwaves can penetrate the interior of durian, achieving three-dimensional synchronous heating, increasing thermal efficiency by 10-20 times, and eliminating the need for preheating, thus meeting the demands of rapid industrial production. The thermal effect raises the temperature of water within microorganisms, disrupting protein structures, while the non-thermal effect interferes with cell membrane potential, providing dual protection for efficient low-temperature sterilization. In terms of flavor, microwaves cleverly resolve the "fragrant and pungent" contradiction of durian, promoting the conversion of sulfur-containing compounds into roasting aroma components, reducing odor, and simultaneously triggering fructose caramelization to enhance sweetness. Regarding texture and nutrient retention, low-temperature short-time treatment allows for uniform evaporation of moisture inside the pulp, gradually softening the fiber structure, preventing fiber breakage, hardening, and browning, and maintaining a dense texture. It also reduces the degradation of heat-sensitive nutrients such as vitamin C, inhibits excessive browning, and enhances the product's color and nutritional value.

[0021] Optionally, in step S3, water is added before shearing and pulping to control the overall moisture content of the material at 60%-70%.

[0022] By adopting the above technical solution, the steaming process softens the fibers and particles in durian. While still hot, it is diluted with water through high-frequency shearing force to eliminate the grainy texture and form a uniform and stable emulsion or suspension, avoiding product layering or sedimentation and improving the smoothness of the taste.

[0023] Optionally, in step S3, the flavor modifier is lemon peach leaf, and the amount of lemon peach leaf added is 0.5% of the total mass of durian pulp.

[0024] By adopting the above technical solution, lemon peach leaves are added during the cutting process. Cutting can evenly disperse the lemon peach leaves in the durian puree, avoiding excessively high or low local concentrations, improving its contact efficiency with free radicals, thereby reducing the chance of browning of durian, maintaining the color stability of durian puree, and reducing the bacterial growth rate of durian puree.

[0025] Optionally, in step S3, the pressure of high-pressure homogenization is 25-35 MPa.

[0026] By adopting the above technical solutions, the high-pressure homogenization process refines and evenly mixes durian pulp, milk, sugar, and other components through high-pressure shearing, impact, and cavitation effects, reducing particle size and density differences and resulting in a uniform and viscous texture. After homogenization, the pectin in the durian syrup can better bind with the pulp and emulsion, stabilizing the product structure. High-pressure homogenization also breaks down fat globules in the milk, dispersing them evenly in the emulsion and preventing fat from floating and avoiding stratification and sedimentation. Furthermore, the uniformly dispersed emulsion system reduces the hiding places for microorganisms, decreases the overall contact area between the material and oxygen, delays oxidation and deterioration, and reduces the risk of contamination. In addition, the homogenized durian syrup has improved gloss and fluidity, preventing clumping and hardening due to moisture loss.

[0027] Optionally, in step S4, the conditions for ultra-high temperature instantaneous sterilization are: treatment at 135-150℃ for 2-8 seconds.

[0028] By adopting the above technical solutions, from the perspective of browning, ultra-high temperature instantaneous sterilization, with its extremely short-term (2-8 seconds) high-temperature (135-150℃) treatment, reduces the prolonged exposure of heat-sensitive components, inhibits non-enzymatic browning, and maintains the natural color of the product. In contrast, traditional low-temperature long-term sterilization exacerbates browning. In terms of flavor, ultra-high temperature instantaneous sterilization precisely controls temperature and time, preventing the loss of volatile aroma components and preserving the characteristic aroma of durian, which is superior to traditional steaming and baking. In terms of nutrition, ultra-high temperature instantaneous sterilization shortens the heating time, reduces the degradation of heat-sensitive nutrients such as vitamin C, and has a higher nutrient retention rate than traditional methods. In addition, ultra-high temperature instantaneous sterilization technology is mature, allowing for continuous and automated production without the need for chemical preservatives, resulting in high production efficiency and low cost, meeting the needs of efficient production and market expansion.

[0029] Optionally, the durian pulp in step S1 is the pulp of the Golden Pillow durian.

[0030] On the other hand, the durian syrup provided in this application adopts the following technical solution:

[0031] A durian syrup is prepared by the above-mentioned method for preparing durian syrup.

[0032] In summary, this application includes the following beneficial technical effects:

[0033] 1. By combining bamboo leaf extract and chlorogenic acid pretreatment with ultra-high temperature instantaneous sterilization, enzymatic reactions are blocked in the pretreatment and the heat exposure time is shortened in the posttreatment. The synergistic effect of these two processes effectively inhibits both enzymatic and non-enzymatic browning, thereby reducing durian browning and improving the color stability of durian pudding. Microwave treatment enables rapid and uniform heating, reducing the thermal decomposition time of flavor substances. Ultra-high temperature instantaneous sterilization greatly shortens the high-temperature treatment time. The synergistic effect of these two processes minimizes the loss and destruction of volatile characteristic aroma substances, represented by esters, allowing durian pudding to retain its rich durian flavor. Shearing and high-pressure homogenization thoroughly break down the pulp fibers, forming a uniform and stable emulsion system, making the texture of durian pudding smooth and delicate, avoiding graininess and layering sedimentation, and improving the taste quality. The steps are interconnected and mutually reinforcing, thereby reducing durian browning, preserving the core flavor, and improving the taste of durian pudding.

[0034] 2. Bamboo leaf extract scavenge free radicals through flavonoids, blocking the lipid peroxidation chain reaction and reducing oxidative damage to biomolecules (such as DNA and proteins). Ketones, lactones, and phenolic acids can also react with quinone intermediates to form colorless complexes, blocking the browning chain reaction and reducing lipid oxidation levels, thus reducing the formation of oxidation products such as malondialdehyde (MDA). Chlorogenic acid can form hydroxyl radicals with antioxidant effects, effectively scavenging reactive oxygen species such as superoxide anions and hydroxyl radicals, reducing oxidative stress damage to cells, and blocking enzymatic browning reactions by competitively inhibiting polyphenol oxidase activity and reducing the binding of enzymes to natural substrates.

[0035] Flavonoid glycosides (such as scutellarin and isoscutellarin) in bamboo leaf extract and chlorogenic acid scavenge free radicals through electron transfer or hydrogen atom donation, blocking the chain reaction of aliphatic chain auto-oxidation. The combination of the two can significantly enhance the scavenging ability against superoxide anions and hydroxyl radicals. Thus, by utilizing the synergistic antioxidant and enzyme inhibition effects of bamboo leaf extract and chlorogenic acid, a dual blockade against the oxidation of phenolic substances is formed in the pretreatment stage.

[0036] 3. During intermittent microwave heating, the unique interaction between high-frequency electromagnetic waves and the polar molecules of food allows for the synergistic effect of thermal and non-thermal processes, achieving multiple goals of heating, sterilization, and flavor optimization. Unlike traditional surface heating methods such as steaming and baking, microwaves can penetrate the interior of the durian, achieving three-dimensional simultaneous heating, increasing thermal efficiency by 10-20 times, and eliminating the need for preheating, thus meeting the demands of rapid industrial production. The thermal effect raises the temperature of water within microorganisms, disrupting protein structures, while the non-thermal effect interferes with cell membrane potential, providing dual protection for efficient low-temperature sterilization. In terms of flavor, microwaves cleverly resolve the "fragrant and pungent" contradiction of durian, promoting the conversion of sulfur-containing compounds into roasting aroma components, reducing odor, and simultaneously triggering fructose caramelization to enhance sweetness. Regarding texture and nutrient retention, low-temperature, short-time treatment allows for uniform evaporation of moisture within the pulp, gradually softening the fiber structure, preventing fiber breakage, hardening, and browning, and maintaining a smooth texture. It also reduces the degradation of heat-sensitive nutrients such as vitamin C, inhibits excessive browning, and enhances the product's color and nutritional value. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0038] In the diagram:

[0039] Figure 1 The durian syrup is obtained by the preparation methods of Example 2, Comparative Example 9, Comparative Example 14, Comparative Example 4, Comparative Example 6, and Comparative Example 15 of this application. Detailed Implementation

[0040] This application discloses a method for preparing durian syrup.

[0041] Example 1:

[0042] The preparation method of durian nectar includes S1: raw material processing: soaking durian pulp in a low-temperature aqueous solution containing bamboo leaf extract and chlorogenic acid;

[0043] The durian pulp is from the Golden Pillow durian; the low-temperature aqueous solution containing bamboo leaf extract and chlorogenic acid includes bamboo leaf extract with a mass concentration of 0.1% and chlorogenic acid with a mass concentration of 0.1%; the soaking is carried out at 4℃ (low temperature) for 15 minutes.

[0044] S2: Microwave treatment: Intermittently microwave the soaked durian pulp until it softens;

[0045] The intermittent microwave heating method has a power of 500W. The specific operation includes heating for 1 minute, then removing and stirring, then heating for another 30 seconds, and repeating this cycle 2-3 times.

[0046] S3: Shearing and homogenization: Add water, lemon peach leaves, milk and sugar to the microwave-treated durian puree, adjust the moisture content and shear and beat the puree, then homogenize the puree under high pressure.

[0047] The mass fraction ratio of sugar, milk and durian puree is as follows: sugar 5%, milk 80%, durian puree 15%. Water is added before shearing and pulping to control the overall moisture content of the material at 60%-70%.

[0048] The amount of lemon-scented peach leaves added was 0.5% of the total mass of durian pulp in S1;

[0049] The pressure for high-pressure homogenization is 25-35 MPa.

[0050] S4: Sterilization: The homogenized slurry is subjected to ultra-high temperature instantaneous sterilization treatment;

[0051] The conditions for ultra-high temperature instantaneous sterilization are: treatment at 135-150℃ for 2-8 seconds.

[0052] Example 2:

[0053] The difference between this embodiment and Embodiment 1 is that in step S1, the low-temperature aqueous solution containing bamboo leaf extract and chlorogenic acid includes bamboo leaf extract with a mass concentration of 0.2% and chlorogenic acid with a mass concentration of 0.2%.

[0054] Everything else is the same as in Example 1.

[0055] Example 3:

[0056] The difference between this embodiment and Embodiment 1 is that in step S1, the low-temperature aqueous solution containing bamboo leaf extract and chlorogenic acid includes bamboo leaf extract with a mass concentration of 0.3% and chlorogenic acid with a mass concentration of 0.3%.

[0057] Everything else is the same as in Example 1.

[0058] Comparative Example 1:

[0059] The difference between this comparative example and Example 1 is that the durian is not soaked in step S1.

[0060] Everything else is the same as in Example 1.

[0061] Comparative Example 2:

[0062] The difference between this comparative example and Example 1 is that in step S1, the low-temperature aqueous solution only contains bamboo leaf extract with a mass concentration of 0.2%.

[0063] Everything else is the same as in Example 1.

[0064] Comparative Example 3:

[0065] The difference between this comparative example and Example 1 is that in step S1, the low-temperature aqueous solution contains only chlorogenic acid with a mass concentration of 0.2%.

[0066] Everything else is the same as in Example 1.

[0067] Comparative Example 4:

[0068] The difference between this comparative example and Example 1 is that in step S1, the low-temperature aqueous solution includes 0.2% sodium D-isoascorbate.

[0069] Everything else is the same as in Example 1.

[0070] Comparative Example 5:

[0071] The difference between this comparative example and Example 1 is that in step S1, the low-temperature aqueous solution containing bamboo leaf extract and chlorogenic acid includes bamboo leaf extract with a mass concentration of 0.05% and chlorogenic acid with a mass concentration of 0.2%.

[0072] Everything else is the same as in Example 1.

[0073] Comparative Example 6:

[0074] The difference between this comparative example and Example 1 is that in step S1, the low-temperature aqueous solution containing bamboo leaf extract and chlorogenic acid includes bamboo leaf extract with a mass concentration of 0.4% and chlorogenic acid with a mass concentration of 0.2%.

[0075] Everything else is the same as in Example 1.

[0076] Comparative Example 7:

[0077] The difference between this comparative example and Example 1 is that in step S1, the low-temperature aqueous solution containing bamboo leaf extract and chlorogenic acid includes bamboo leaf extract with a mass concentration of 0.2% and chlorogenic acid with a mass concentration of 0.05%.

[0078] Everything else is the same as in Example 1.

[0079] Comparative Example 8:

[0080] The difference between this comparative example and Example 1 is that in step S1, the low-temperature aqueous solution containing bamboo leaf extract and chlorogenic acid includes bamboo leaf extract with a mass concentration of 0.2% and chlorogenic acid with a mass concentration of 0.4%.

[0081] Everything else is the same as in Example 1.

[0082] Comparative Example 9:

[0083] The difference between this comparative example and Example 1 is that the microwave treatment in step S2 is replaced by steaming, which is carried out for 30 minutes until the durian pulp softens.

[0084] Everything else is the same as in Example 1.

[0085] Comparative Example 10:

[0086] The difference between this comparative example and Example 1 is that no cutting process is performed in step S3.

[0087] Everything else is the same as in Example 1.

[0088] Comparative Example 11:

[0089] The difference between this comparative example and Example 1 is that lemon peach leaves are not added during the cutting process in step S3.

[0090] Everything else is the same as in Example 1.

[0091] Comparative Example 12:

[0092] The difference between this comparative example and Example 1 is that 0.4% lemon myrtle leaves were added in step S3.

[0093] Everything else is the same as in Example 1.

[0094] Comparative Example 13:

[0095] The difference between this comparative example and Example 1 is that 0.6% lemon myrtle leaves were added in step S3.

[0096] Everything else is the same as in Example 1.

[0097] Comparative Example 14:

[0098] The difference between this comparative example and Example 1 is that no homogenization process is performed in step S3.

[0099] Comparative Example 15:

[0100] The difference between this comparative example and Example 1 is that step S4 uses a traditional low-temperature long-time sterilization process, which is treated at 121°C for 18 minutes.

[0101] The durian syrups obtained in Examples 1-3 and Comparative Examples 1-15 were subjected to the following tests, and 30 volunteers were selected to observe and taste the color, smoothness, and flavor for sensory evaluation.

[0102] Table 1: Detection 1: OD value of browning index (A) 420The following test was conducted: 1 g of durian syrup was mixed with 10 mL of 80% ethanol solution and reacted in the dark at room temperature for 0.5 h, stirring every 5 min. The mixture was then centrifuged at 8000 r / min for 10 min at 4℃. The supernatant was collected and the absorbance was measured at a wavelength of 420 nm.

[0103] Detection 2: Retention rate of ethyl 2-methylbutyrate was tested. The following detection method was used: headspace-solid phase microextraction (HS-SPME) was employed to determine volatile flavor compounds. A 2g sample unit was diluted to 20mL with distilled water and homogenized in a high-speed homogenizer at 10000 rpm for 2 minutes. 5mL of homogenate, 1g of sodium chloride, 2μL of 5μ / mL cyclohexanone solution, and a magnetic stir bar were added to the extraction flask. The solid phase extraction head was inserted and adsorbed at 60℃ for 30 minutes. Then, the extraction head was inserted into the GC-MS inlet for sample injection, and the sample was desorbed at 250℃ for 5 minutes.

[0104] Chromatographic conditions: Column: DB-5MS capillary column (30m × 250um, 0.25um); Temperature program: Initial temperature of the column was 40℃, held for 2 min; increased to 120℃ at a rate of 5℃ / min, held for 3 min; increased to 230℃ at a rate of 10℃, held for 3 min. Carrier gas: He; Flow rate: 1.0 mL / min; Split ratio: 20:1.

[0105] Mass spectrometry conditions: Ion source (EI) temperature 230℃; electron energy 70 eV; scan mode Scan; scan range 30~450 aum.

[0106] Qualitative analysis: Volatile components detected by GC-MS were qualitatively analyzed by computer matching with two standard spectral libraries, Wiley and NIST 08. The samples underwent GC-MS volatile component detection.

[0107] Quantitative analysis: Semi-quantitative analysis was performed using the peak area normalization method, as shown in the following formula:

[0108] C i =(S i ×M0) / (S0×M d )

[0109] In the formula C i Si: Peak area of ​​a certain component; S0: Peak area of ​​the internal standard; M0: Mass of the internal standard, μg; M d : Mass of the added test sample (all considered to be 2g of fresh durian in the initial stage), g.

[0110] The retention rate of ethyl 2-methylbutyrate is calculated using the following formula:

[0111] R i =(C ie / C i0 ) x100

[0112] In the formula R i Retention rate of ethyl 2-methylbutyrate, %; C ie : Content of ethyl 2-methylbutyrate in different samples, μg / g; C i0 : Content of ethyl 2-methylbutyrate in fresh samples, μg / g.

[0113] Test 3: The centrifugation sedimentation rate was tested. The following test method was used: 1g of durian syrup sample was weighed and placed into a centrifuge tube. The total weight of the sample and the centrifuge tube was recorded as m1. The centrifuge tube was placed in a centrifuge and centrifuged at 3000r / min for 10min. After centrifugation, the supernatant was poured out and allowed to stand for 10min to remove residual liquid. The total weight of the precipitate and the centrifuge tube was then weighed as m2.

[0114] Centrifugal sedimentation rate (%) = (m2 - m1) × 100%

[0115] Table 2: Sensory evaluation results of color, fineness, and flavor observation and tasting.

[0116] Figure 1 Specifically, the images are of durian sago from Examples 2, 4, 9, 6, 14, and 15.

[0117] Table 1:

[0118]

[0119] Browning index OD value (A 420 The data in the table are expressed as mean ± standard deviation; different letters indicate significant differences. P <0.05).

[0120] Based on Table 1, the results of the browning index (OD value), ethyl 2-methylbutyrate retention rate, and centrifugation sedimentation rate of durian nectar were analyzed.

[0121] Regarding the browning index (OD) value of durian nectarine.

[0122] The durian gan puddings from Examples 1-3 had the lowest browning index, with Example 2 having the lowest browning index of only 0.154, indicating that Example 2 had the lowest degree of browning. This demonstrates that the soaking regimens of Examples 1-3 were effective in reducing the browning degree of durian gan puddings.

[0123] Compared with Examples 1-3, the durian chunks in Comparative Example 1 were not soaked, and the browning index of the finished durian nectar was significantly higher than that of other groups.

[0124] Comparative Examples 2-8 showed an increase in browning index compared to Examples 1-3 when using a single raw material for soaking, adjusting the proportion of the soaking material, or using other antioxidants. This indicates that the content of the soaking material (adjusting the proportion) and the replacement of bamboo leaf extract and chlorogenic acid with the antioxidant sodium D-isoascorbate will affect the browning index. Therefore, only the preparation method of Examples 1-3 can achieve better results.

[0125] Comparative Example 9 used steaming to soften durian fibers, which increased its browning index. This was likely due to the excessively long steaming time, which caused the durian flesh to come into contact with oxygen. However, the influence of other conditions such as temperature and humidity during the steaming process cannot be ruled out.

[0126] Comparative Examples 11-13 adjusted the amount of lemon myrtle leaves added during the cutting process and found that the addition of lemon myrtle leaves could also reduce the browning index of the finished product. The optimal concentration of lemon myrtle leaves was 0.5%, and both decreasing and increasing the concentration affected the browning index. Comparative Example 15 used a traditional sterilization process, which extended the sterilization time. The sugars and proteins in durian reacted for a longer time at high temperatures, increasing the degree of browning.

[0127] Regarding the retention rate of ethyl 2-methylbutyrate.

[0128] The durian syrup samples of Examples 1-3 showed relatively high retention rates of ethyl 2-methylbutyrate, meaning relatively high content and low loss rates. Comparative Examples 10 and 14 showed lower retention rates, slightly higher loss rates, and slightly lower content of ethyl 2-methylbutyrate. Comparative Examples 2-8 and 11-13 showed lower retention rates, higher loss rates, and lower content of ethyl 2-methylbutyrate. This indicates that Examples 1-3 have a certain advantage in retaining ethyl 2-methylbutyrate.

[0129] Comparative Example 9 used steaming to soften durian flesh, and its ethyl 2-methylbutyrate retention rate was low, loss rate was high, and content was low. This may be because the steaming time was long, and other factors such as temperature and pressure affected the retention of volatile flavor substances.

[0130] The retention rates of ethyl 2-methylbutyrate in durian syrups from comparative examples 6, 8, and 13, which had excessive amounts of infusion, were lower. This may be due to the flavor of the infusion masking or destroying the flavor of the durian, or it may have triggered other chemical reactions that affect the stability of ethyl 2-methylbutyrate.

[0131] The product obtained by the low-temperature, long-time sterilization process in Comparative Example 15 showed a lower retention rate, higher loss rate, and lower content of ethyl 2-methylbutyrate. This may be because ethyl 2-methylbutyrate itself underwent decomposition and volatilization during the sterilization process. These results are consistent with the sensory evaluation results in Table 2.

[0132] Regarding the centrifugal sedimentation rate.

[0133] The durian sago from Examples 1-3 exhibited the lowest centrifugal sedimentation rate, indicating the most uniform product condition. Comparative Example 14, without the homogenization step, showed a significantly higher centrifugal sedimentation rate than the other groups. This demonstrates that the homogenization process in this example significantly improves the product's condition and uniformity.

[0134] Compared with Examples 1-3, the centrifugal sedimentation rate of durian pulp in Comparative Example 1 that was not soaked was slightly higher than that in Examples 1-3. This may be because the soaking process softens the durian pulp, changes its structure, makes it looser, and thus makes it easier to mix evenly with other ingredients, ultimately improving the product quality.

[0135] In Comparative Example 9, changing the durian softening step from microwave to steaming, or in Comparative Example 10, omitting the shearing step, both significantly increased the centrifugal sedimentation rate. This may be because the processing cannot completely break down the durian fibers, making it difficult to mix evenly with other ingredients, ultimately resulting in a less smooth finished product. Alternatively, the overall viscosity of the product may change, thus affecting the centrifugal sedimentation rate.

[0136] Furthermore, the durian syrup produced by Comparative Example 15 using a traditional low-temperature long-time sterilization process had higher sedimentation levels than the Example. Considering factors such as product condition and flavor, it was concluded that ultra-high temperature instantaneous sterilization is more suitable as the sterilization process for this product.

[0137] Table 2:

[0138]

[0139] As shown in Table 2, the durian syrups from Examples 1-3 exhibit a bright yellow color and a rich aroma of durian pulp. Through experiments with multiple control groups, it was found that removing the shearing step in Comparative Example 10 and removing the homogenization step in Comparative Example 14 reduced the smoothness of the durian syrup. In particular, removing the homogenization step resulted in a noticeable grainy texture in the durian syrup.

[0140] Comparative Examples 1, 4, 6, 7, 11, and 13 show that if durian flesh is not soaked or if the proportions of bamboo leaf extract and chlorogenic acid aqueous solution used in the comparative examples are used for soaking, the flavor of the durian syrup will be affected. Specifically, the durian flavor will be weakened, the color of the finished product will be changed, and the eating experience will be affected.

[0141] Comparative Example 15 shows that using a low-temperature, long-duration sterilization process may cause the product to develop a sweet taste due to the Maillard reaction, and the product color may change to a milky apricot color.

[0142] Figure 1 The first row shows durian syrups prepared in Example 2, Comparative Example 9, and Comparative Example 14, respectively; the second row shows durian syrups prepared in Comparative Example 4, Comparative Example 6, and Comparative Example 15, respectively.

[0143] As can be seen from the image, the durian syrup in Example 2 has a bright yellow color and a good appearance. In Comparative Example 9, the steaming time was too long, which accelerated the oxidation of the durian and caused the color to darken. Comparative Example 14 lacked a homogenization process, resulting in a noticeable grainy texture in the finished durian syrup.

[0144] Comparative Example 4 used a different soaking solution, which masked the natural color of the durian, altering its appearance and reducing consumer appetite. Comparative Example 6 added excessive bamboo leaf extract, which similarly masked the natural color of the durian, altering its appearance and reducing consumer appetite. Comparative Example 15 used low-temperature, long-term sterilization, giving the durian a brownish hue, making it significantly less appealing than Example 2.

[0145] The preparation methods described in Examples 1-3 can improve the fineness and uniformity of durian syrup, enhance the overall color, and take into account both taste and microbial safety, thus better meeting consumer demand.

[0146] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0147] It should be understood that, as used herein, the singular form "a" is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations of one or more of the associatedly listed items. The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0148] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for preparing durian syrup, characterized in that: Includes the following steps: S1: Raw material processing: Soak durian pulp in a low-temperature aqueous solution containing a mixture of bamboo leaf extract and chlorogenic acid; soaking is carried out at 4°C; S2: Microwave treatment: Intermittently microwave the soaked durian pulp until it softens to obtain durian puree; S3: Shearing and homogenization: Add water, lemon peach leaves, milk and sugar to the microwave-treated durian puree, adjust the moisture content and shear and beat the puree, then homogenize the puree under high pressure. S4: Sterilization: The homogenized slurry is subjected to ultra-high temperature instantaneous sterilization treatment; In step S1, the low-temperature aqueous solution containing the mixture of bamboo leaf extract and chlorogenic acid comprises bamboo leaf extract with a mass concentration of 0.1%-0.3% and chlorogenic acid with a mass concentration of 0.1%-0.3%. In step S3, the amount of lemon peach leaves added is 0.5% of the total mass of durian pulp in S1.

2. The method for preparing durian syrup according to claim 1, characterized in that: In step S1, the soaking time is 15 minutes.

3. The method for preparing durian syrup according to claim 1, characterized in that: In step S2, the power of the intermittent microwave heating is 500W. The specific operation includes: heating for 1 minute, then taking it out and stirring, then heating for another 30 seconds, and repeating this cycle 2-3 times.

4. The method for preparing durian syrup according to claim 1, characterized in that: In step S3, water is added before shearing and pulping to control the overall moisture content of the material at 60%-70%.

5. The method for preparing durian syrup according to claim 1, characterized in that: In step S3, the pressure for high-pressure homogenization is 25-35 MPa.

6. The method for preparing durian syrup according to claim 1, characterized in that: In step S4, the conditions for ultra-high temperature instantaneous sterilization are: treatment at 135-150℃ for 2-8 seconds.

7. The method for preparing durian syrup according to claim 1, characterized in that: The durian pulp mentioned in step S1 is the pulp of the Golden Pillow durian.

8. A durian syrup, characterized in that: It is prepared by the method of preparation of durian syrup as described in any one of claims 1-7.

Images