Preparation method of pandan coconut juice beverage

Abstract

The invention discloses a preparation method of a pandan coconut milk beverage. The preparation method comprises the following steps: a coconut milk preparation process; pretreating a fresh pandan leaf enzyme preparation and preparing pandan pulp; compounding and emulsifying; and performing high-pressure homogenization and sterilization. According to the preparation method, the fresh natural plant pandan is processed by adopting an enzymolysis combined high-speed homogenization method to prepare the pandan primary pulp, the natural plant mint component is innovatively added, the special rich fragrance of pandan leaves after high temperature is effectively blended, the unique rich fragrance and the mellow fragrance of coconut meat form a well-layered composite fragrance system, and the sensory quality of the product is remarkably improved. In the aspect of nutrient enrichment, the dietary fiber component fructo-oligosaccharide is scientifically matched, so that the defect of dietary fiber in the traditional coconut juice beverage is overcome. The prepared pandan coconut juice beverage has excellent system stability, the innovative flavor combination breaks through the taste framework of a traditional product, and meanwhile, through the synergistic interaction effect of functional ingredients, double improvement of nutrition balance and sensory experience is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of beverage drinks, and particularly relates to a preparation method of a pandan coconut juice drink. Background Art

[0002] Pandan coconut juice is a plant protein drink made from high-quality pandan leaves with tropical characteristics in Hainan and fresh coconut meat, which is finely processed in sections and scientifically proportioned. In existing pandan coconut juice products, in terms of product stability, the rich protein and fat components in coconut juice cause the product to easily layer and precipitate during storage; in terms of raw material treatment, freshly squeezed pandan leaves are extremely easy to oxidize, and if the treatment process is improper, it will lead to a deterioration in the color and taste of the product; in terms of the sterilization process, traditional high-temperature long-time sterilization at 121°C (20 minutes) destroys the stability and flavor characteristics of the product.

[0003] The stabilizer components used in single coconut juice products on the market are simple. However, after adding the plant component pandan, the use of the original single stabilizer alone cannot meet the product stability. Therefore, in the present invention, an emulsifying stabilizer for a pandan coconut juice drink is obtained through compatibility on the basis of original mono- and diglycerides.

[0004] Existing products mostly use pandan powder for blending. However, due to the limitations of freeze-drying and pulverization technology, the products have quality defects such as obvious fiber feeling and rough taste; at the same time, after high-temperature treatment, the pandan flavor is too strong, covering up the unique mellow fragrance of coconut juice, and it is difficult to achieve an ideal flavor balance between the two.

[0005] Therefore, it is necessary to propose a preparation method of a pandan coconut juice drink to solve the above problems. Summary of the Invention

[0006] In view of the problem of poor taste and quality of existing natural pandan coconut juice drinks, the present invention proposes a preparation method of a pandan coconut juice drink.

[0007] The preparation method of this pandan coconut juice drink includes the following steps:

[0008] S1. Preparation of coconut milk;

[0009] S2. Pretreatment of fresh pandan leaves with enzyme preparation and preparation of pandan pulp;

[0010] S3. Compound blending and emulsification operation;

[0011] S4. Homogenization and sterilization.

[0012] In a preferred embodiment of the present invention, the method for preparing coconut milk in S1 is as follows: Manually crack the shell to obtain fresh coconut meat, remove the black skin on the surface, and rinse with cold water until there is no impurity; After cutting the coconut meat into pieces, place it in a microwave device for microwave treatment with a power of 500 - 800W and a time of 1 - 2 minutes; After microwave treatment, soak the coconut meat in hot water at 80°C for 2 - 3 minutes to soften the tissue, then put it into a wall breaker and make a pulp according to the ratio of coconut meat to hot water of 1:1, and at the same time turn on the ultrasonic assistance device with a frequency of 20 - 40kHz and a power of 200 - 400W to perform ultrasonic treatment during pulping for 5 - 10 minutes to obtain crude coconut milk; Squeeze and separate the coconut milk and fibers through a 200 - mesh filter bag, collect the initially filtered coconut milk, and re - pulp the remaining coconut flakes, add hot water at 80°C with a ratio of 1:1 to the coconut flakes, and filter through 200 - mesh to fully extract the active ingredients; Combine the coconut milk filtered twice to obtain coconut milk.

[0013] Further, the specific method for treating fresh pandan leaves with enzyme preparation in S2 is as follows: Uniformly apply 1wt% sodium bicarbonate solution on the fresh pandan leaves. After the surface of the leaves is uniformly adhered, put them into the refrigerator and freeze for 24h to rupture the cell membranes of the leaves; Cut the fresh pandan leaves, blanch the pandan leaf segments with hot water at 80°C, and use ultrasonic technology to treat the pandan leaf segments during blanching with an ultrasonic power of 120W and ultrasonic treatment for 20 - 30min. Cool the blanched pandan leaves, and add an enzyme preparation composed of tannase and polyphenol oxidase with an addition ratio of 2:1 at a temperature of 30 - 60°C and a pH of 5 - 6 to treat the pandan leaf segments. The concentration of tannase is 0.2 - 1.5U / mL, the concentration of polyphenol oxidase is 0.1 - 0.75U / mL, the treatment time is 0.5 - 1.0h, and the ratio of the mixed enzyme solution to the pandan leaves in terms of solid - liquid ratio is 1:10 - 1:4. This treatment is mainly used to decompose phenolic substances to remove astringency.

[0014] Further, the method for preparing pandan pulp in S2 is that the pandan puree uses a composite enzyme preparation for treatment and adds herbs to reconcile the flavor and improve the product quality. Specifically: Mix the pandan leaf segments pretreated with the composite enzyme preparation and fresh mint leaves in a weight ratio of 9:1, put them into a high - speed juicer for homogenization, the rotation speed of the high - speed juicer > 10000r / min, and after homogenization, filter through 200 - mesh to obtain pandan pulp with a unique flavor.

[0015] Further, the compounding and emulsifying operation steps in S3 are as follows: First, pre-emulsify 7 - 12 parts of coconut milk for 1 minute; Second, pre-dissolve the following auxiliary materials with 80°C hot water respectively: 0.3 - 0.35 parts of stabilizer, 0.3 - 0.5 parts of sodium caseinate, 5 - 7 parts of granulated sugar, 0.5 - 1 part of fructooligosaccharide, 0.02 - 0.05 parts of baking soda, and pre-emulsify for 1 minute; and sequentially add them to the pre-emulsified coconut milk, continue to mix and emulsify at a constant temperature of 80°C for 1 - 2 minutes, add 0.5 - 1 part of pandan pulp, add purified water to make up to 100 parts, and emulsify for 6 minutes; control the concentration consistency by the amount of added water, so that the content of coconut meat in the product accounts for 70 - 120 g / L.

[0016] In a preferred embodiment of the present invention, the dietary fiber is fructooligosaccharide in water-soluble dietary fiber.

[0017] In a preferred embodiment of the present invention, the stabilizer is an emulsifying stabilizer composed of 0.1350 - 0.1575 parts of mono- and diglycerol fatty acid esters, 0.090 - 0.105 parts of sodium stearoyl lactate, 0.0330 - 0.0385 parts of maltodextrin, 0.018 - 0.021 parts of sodium citrate, 0.006 - 0.007 parts of xanthan gum, 0.006 - 0.007 parts of guar gum, 0.006 - 0.007 parts of sodium alginate, and 0.006 - 0.007 parts of sodium carboxymethylcellulose.

[0018] Further, the specific steps of homogenization and sterilization in S4 are as follows: Adopt a two-stage gradient homogenization process: 30 MPa for the first time and 35 MPa for the second time to ensure that the particle size ≤ 2 μm; finally, adopt ultra-high temperature instantaneous sterilization, UHT, at 139 - 141°C / 9 - 15 s, and quickly cool to below 25°C for filling to obtain the natural pandan coconut juice beverage.

[0019] Implementing the embodiments of the present invention has the following beneficial effects:

[0020] The natural pandan coconut juice beverage produced by the preparation method of the pandan coconut juice beverage of the present invention has high stability, and better preserves the color, flavor and taste of coconut juice and pandan; adding an enzyme preparation for pretreatment of pandan leaves effectively removes the astringency and reduces browning; at the same time, adding mint, the aroma of mint plays a role in modifying the strong "zongzi fragrance" of pandan, achieving a perfect balance between the pandan flavor and the mellow fragrance of coconut meat. Compared with traditional single coconut juice beverages, this product creates a rich and unique taste experience, bringing a new sensory enjoyment to consumers. Through technological and formulation innovation, the present invention not only solves the technical bottleneck in the industry, but also provides more competitive product choices for the plant protein beverage market. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 Photos of five stabilizers after 0 days of sterilization;

[0023] Figure 2 Photos of five stabilizers after 7 days of sterilization;

[0024] Figure 3 Photos of five stabilizers after 11 days of sterilization;

[0025] Figure 4 Photos of five stabilizers after 14 days of sterilization;

[0026] Figure 5 Photos of five stabilizers after 18 days of sterilization;

[0027] Figure 6 Radar charts of stabilizer 1 and stabilizer 3;

[0028] Figure 7 Electronic nose analysis charts of stabilizer 1 and stabilizer 3;

[0029] Figure 8 Particle size schematic diagram of sample 1;

[0030] Figure 9 Particle size schematic diagram of sample 3;

[0031] Figure 10 Zeta potential schematic diagrams of pandan coconut juice of samples 1 and 3;

[0032] Figure 11 Near-infrared spectra of samples 1 and 3;

[0033] Figure 12 Effect of coconut meat addition amount on sensory score

[0034] Figure 13 Effect of pandan addition amount on sensory score

[0035] Figure 14 Effect of casein addition amount on sensory score

[0036] Figure 15 Effect of white granulated sugar addition amount on sensory score

[0037] Figure 16 Photo of the stable state of the 0h sample;

[0038] Figure 17 It is a photo of the stable state of the 1h sample;

[0039] Figure 18 It is a photo of the stable state of the 3h sample;

[0040] Figure 19 It is a photo of the stable state of the 4h sample;

[0041] Figure 20 It is a photo of the stable state of the 5h sample;

[0042] Figure 21 It is a photo of the stable state of the 24h sample;

[0043] Figure 22 It is a photo of the stable state of the 72h sample;

[0044] Figure 23 It is a radar chart of the sample;

[0045] Figure 24 It is a PCA chart of the sample. Specific implementation mode

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] The preparation method of this pandan coconut juice beverage includes the following steps:

[0048] S1. Preparation of coconut milk: Manually crack the fresh coconut to obtain the coconut meat, remove the black skin on the surface, and rinse it with cold water until there is no impurity; after cutting the coconut meat into pieces, place it in a microwave device for microwave treatment with a power of 500 - 800W and a time of 1 - 2 minutes; after microwave treatment, soak the coconut meat in 80°C hot water for 2 - 3 minutes to soften the tissue, and then put it into a wall breaker to make pulp according to the ratio of coconut meat to hot water of 1:1, and at the same time turn on the ultrasonic auxiliary device with a frequency of 20 - 40kHz and a power of 200 - 400W to perform ultrasonic treatment for 5 - 10 minutes during pulping to obtain crude coconut milk; squeeze and separate the coconut milk and fibers through a 200 - mesh filter bag, collect the initially filtered coconut milk, and re - pulp the remaining coconut shreds, add 80°C hot water with a ratio of 1:1 to the coconut shreds, and filter through 200 - mesh to fully extract the active ingredients; combine the coconut milk filtered twice to obtain coconut milk.

[0049] S2. Pretreatment of fresh pandan leaves with enzyme preparation and preparation of pandan pulp:

[0050] The specific method for treating fresh pandan leaves with enzyme preparation is as follows: evenly apply 1 wt% sodium bicarbonate solution on the fresh pandan leaves. After the leaf surface is evenly attached, put them into the refrigerator and freeze for 24 h to rupture the cell membrane of the leaves. Cut the fresh pandan leaves, blanch the pandan leaf segments with 80°C hot water, and use ultrasonic technology to treat the pandan leaf segments during the blanching process. The ultrasonic power is 120 W, and ultrasonic treatment is carried out for 20 - 30 min. Cool the blanched pandan leaves, and add an enzyme preparation composed of tannase and polyphenol oxidase with an addition ratio of 2:1 at a temperature of 30 - 60°C and a pH of 5 - 6 to treat the pandan leaf segments. This treatment is mainly used to decompose phenolic substances to remove astringency.

[0051] The preparation method of pandan pulp is as follows: mix the pandan leaf segments pretreated with the composite enzyme preparation and fresh mint leaves at a weight ratio of 9:1, put them into a high-speed juicer for pressing. The rotation speed of the high-speed juicer is >10000 r / min. After pressing, filter with a 200-mesh sieve to obtain pandan pulp with a unique flavor.

[0052] S3. Compound and emulsify operation:

[0053] The compound and emulsify operation steps are as follows: First, pre-emulsify 7 - 12 parts of coconut milk for 1 minute. Second, pre-dissolve the following auxiliary materials with 80°C hot water in sequence: 0.3 - 0.35 parts of stabilizer, 0.3 - 0.5 parts of sodium caseinate, 5 - 7 parts of granulated sugar, 0.5 - 1 part of fructooligosaccharide, 0.02 - 0.05 parts of baking soda, and pre-emulsify for 1 minute; and add them to the pre-emulsified coconut milk in sequence, continue to mix and emulsify at a constant temperature of 80°C for 1 - 2 minutes, add 0.5 - 1 part of pandan pulp, add purified water to make up to 100 parts, and emulsify for 6 min; control the concentration consistency by the amount of added water to make the content of coconut meat in the product account for 70 - 120 g / L.

[0054] The dietary fiber is fructooligosaccharide in water-soluble dietary fiber.

[0055] The stabilizer is an emulsifying stabilizer composed of 0.1350 - 0.1575 parts of mono- and diglycerol fatty acid esters, 0.090 - 0.105 parts of sodium stearoyl lactate, 0.0330 - 0.0385 parts of maltodextrin, 0.018 - 0.021 parts of sodium citrate, 0.006 - 0.007 parts of xanthan gum, 0.006 - 0.007 parts of guar gum, 0.006 - 0.007 parts of sodium alginate, and 0.006 - 0.007 parts of sodium carboxymethylcellulose.

[0056] S4. Homogenize and sterilize: Adopt a two-stage gradient homogenization process: 30 MPa for the first time and 35 MPa for the second time to ensure that the particle size is ≤2 μm; finally, adopt ultra-high temperature instantaneous sterilization, UHT, at 139 - 141°C / 9 - 15 s, and quickly cool to below 25°C for filling to obtain the natural pandan coconut juice beverage.

[0057] The preparation of this pandan coconut natural beverage uses ultra-high temperature instantaneous sterilization technology (UHT sterilization) to effectively protect the flavor, color, and nutritional components of the beverage while extending its shelf life.

[0058] In addition to using different sterilization methods, this solution achieves the purpose of developing a new type of healthy beverage through the following technologies:

[0059] Enzymatic hydrolysis operation of pandan pulp: By controlling temperature, pH value, enzymatic hydrolysis time, and enzyme type, the stability and flavor release of pandan pulp can be improved. In addition, other enzymes (such as hemicellulase or protease) can be tried to further decompose complex polysaccharides and proteins in pandan, enhancing the taste and stability.

[0060] Using ultrasonic technology for pandan pulp treatment, this solution uses ultrasonic waves before the pressing process. Utilizing the cavitation effect and mechanical effect of ultrasonic waves, it accelerates the rupture of pandan cells, improves the pressing efficiency. At the same time, the thermal effect of ultrasonic waves helps to further remove the astringent taste.

[0061] Enzyme preparations are used in the research and development of pandan coconut juice products and are applied to enhance the fragrance of pandan leaves through enzymatic hydrolysis. At the same time, enzyme preparation treatment can degrade proteins in pandan leaves into small molecule substances, thereby improving their dissolution rate and reducing precipitation. It is one of the effective ways to improve the stability of pandan coconut juice.

[0062] When extracting pandan juice, by adding mint extract, its natural antioxidant components such as flavonoids, phenols, and phytosterols can effectively inhibit the activity of polyphenol oxidase in pandan leaves, reduce the oxidation and discoloration of pandan pulp during processing and storage, and can also delay the degradation of lipids, pigments, and other easily oxidized components in pandan pulp, thereby extending the shelf life of the product. In addition, the aroma of mint complements the natural aroma of pandan leaves, forming a more complex and pleasant flavor combination. Moreover, the phenolic compounds contained in mint have a broad-spectrum antibacterial effect, which can inhibit the growth of microorganisms that may exist in pandan pulp, reduce the risk of spoilage and deterioration, and reduce the dependence on chemical preservatives, making the product more natural and healthy. The alcohol and ester components in mint volatile oil work together to form a stable emulsion system.

[0063] Use of emulsifying stabilizers: By compounding different types of stabilizers (a combination of xanthan gum, sodium carboxymethyl cellulose, and sodium alginate), a synergistic effect can be produced, further enhancing the stability and taste of the beverage, increasing the suspension and viscosity of the beverage, and preventing precipitation.

[0064] Comparison of five different compositions of stabilizers:

[0065] Stabilizer 1: Mono- and diglycerol fatty acid esters 45%, sodium stearoyl lactylate 30%, maltodextrin 11%, sodium citrate 6%, xanthan gum 2%, guar gum 2%, sodium alginate 2%, sodium carboxymethyl cellulose 2%.

[0066] Stabilizer 2: Mono- and diglycerol fatty acid esters 40%, sodium stearoyl lactylate 35%, maltodextrin 11%, sodium citrate 6%, xanthan gum 2%, guar gum 2%, sodium alginate 2%, sodium carboxymethyl cellulose 2%.

[0067] Stabilizer 3: Mono- and diglycerol fatty acid esters 45%, sodium stearoyl lactylate 35%, maltodextrin 6%, sodium citrate 6%, xanthan gum 2%, guar gum 2%, sodium alginate 2%, sodium carboxymethyl cellulose 2%. Stabilizer 4: Mono- and diglycerol fatty acid esters 50%, sodium stearoyl lactylate 30%, maltodextrin 6%, sodium citrate 6%, xanthan gum 2%, guar gum 2%, sodium alginate 2%, sodium carboxymethyl cellulose 2%.

[0068] Stabilizer 5: Mono- and diglycerol fatty acid esters 45%, sodium stearoyl lactylate 25%, maltodextrin 11%, sodium citrate 11%, xanthan gum 2%, guar gum 2%, sodium alginate 2%, sodium carboxymethyl cellulose 2%

[0069] Samples were prepared using the above stabilizer formulations with five different ratios, and the stability of the samples after sterilization was compared:

[0070] For the stabilizers at different times 0d, 7d, 11d, 14d, 18d after sterilization, please refer to Figures 1 - 5 ;

[0071] At 0d, floating fat: Stabilizer 1: No floating oil; Stabilizer 2: 1 mm; Stabilizer 3: No floating oil; Stabilizer 4: Less than 1 mm; Stabilizer 5: 1 mm;

[0072] Thickness of the lower layer precipitate: Stabilizer 1: No obvious precipitate; Stabilizer 2: No obvious precipitate; Stabilizer 3: No obvious precipitate; Stabilizer 4: 1 cm; Stabilizer 5: No obvious precipitate.

[0073] At 7d, floating fat; Stabilizer 1: 1.5 mm, showing a small amount of foam; Stabilizer 2: 1 mm, with obvious stratification and obvious separation of floating oil; Stabilizer 3: Almost no floating oil; Stabilizer 4: Less than 1 mm; Stabilizer 5: Less than 1 mm

[0074] Thickness of the lower layer precipitate: Stabilizer 1: No obvious precipitate; Stabilizer 2: There are a small amount of granular suspended substances; Stabilizer 3: No obvious precipitate; Stabilizer 4: 2 cm; Stabilizer 5: 3 cm.

[0075] At 11 d, floating fat: Stabilizer 1: 4 mm (slightly foamy); Stabilizer 2: 3 mm (with an obvious grease layer on the upper layer); Stabilizer 3: There is a small amount of grease pattern on the surface, with a thickness of less than 1 mm; Stabilizer 4: 3 mm; Stabilizer 5: 2 mm;

[0076] Thickness of the lower-layer sediment: Stabilizer 1: No obvious sediment; Stabilizer 2: No obvious sediment; Stabilizer 3: No obvious sediment; Stabilizer 4: 8 mm; Stabilizer 5: 2.2 cm.

[0077] At 14 d, floating fat: Stabilizer 1: 2 mm (slightly foamy); Stabilizer 2: < 2 mm (with an obvious grease layer on the upper layer); Stabilizer 3: < 1 mm; Stabilizer 4: 1 mm; Stabilizer 5: < 1 mm

[0078] Thickness of the lower-layer sediment: Stabilizer 1: A small amount of dark sediment; Stabilizer 2: A small amount of white sediment; Stabilizer 3: No obvious sediment; Stabilizer 4: < 1 cm; Stabilizer 5: There is more sediment at the bottom of the bottle, 3 cm.

[0079] At 18 d, floating fat: Stabilizer 1: 8 mm (slightly foamy); Stabilizer 2: 3 mm (with an obvious grease layer on the upper layer); Stabilizer 3: < 2 mm; Stabilizer 4: < 1 mm; Stabilizer 5: < 2 mm

[0080] Thickness of the lower-layer sediment: Stabilizer 1: A trace amount of green sediment; Stabilizer 2: A small amount of green sediment; Stabilizer 3: A small amount of green sediment; Stabilizer 4: There are a large number of suspended sediments in the bottle; Stabilizer 5: There is a large amount of sediment at the bottom of the bottle, 4 cm.

[0081] Due to the addition of pandan, a small amount of dark sediment is a normal phenomenon. The floating grease layer indicates that the stabilizer has poor effect and cannot play a role in stabilizing the solution. The floating small amount of foam layer indicates a relatively high protein content. Appropriately reducing the protein content may significantly improve the stability.

[0082] By monitoring the products under five stabilizer formulation processes, those with better stability are Stabilizer 1 and Stabilizer 3. A review panel consisting of 21 professionals was invited to conduct a sensory evaluation of pandan coconut juice from four aspects: color, flavor, taste, and texture state. The specific evaluation criteria are shown in Table 2-4. The scores of the products formed by the two stabilizer formulations are shown in Table 1. Statistics show that the sensory flavor of the product formed by the Stabilizer 3 formulation is better than that of Stabilizer 1. The sensory scores of the samples of Stabilizer 1 and Stabilizer 3 are 89.19 and 82.37 points respectively.

[0083] Table 1 Product Scoring Standard Table

[0084]

[0085]

[0086] Samples of stabilizers 1 and 3 were respectively detected for their aroma components by 14 sensors (responding to substances / reference substances (groups): 1 part alkanes / propane, smoke; 2 part alkanes / alcohol, smoke, isobutane, formaldehyde; 3 ozone / ozone; 4 sensitive to sulfides / hydrogen sulfide; 5 nitrogen (oxygen) compounds, amines / ammonia, nitrogen dioxide, methylamine, aniline; 6 alcohols, (alkene) aldehydes, ketones, ethers, etc. / acetone, ethanol, ether, etc.; 7 sensitive to short-chain alkanes / methane, etc.; 8 sensitive to short-chain alkanes / propane, etc.; 9 aromatic compounds, etc. / toluene, etc.; 10 hydrides / H2; 11 VOC / hydrocarbons, halogenated hydrocarbons, oxygenated hydrocarbons and nitrogenated hydrocarbons; 12 part alkanes, esters / methane, etc.; 13 long-chain alkanes / CH3; 14 part alkanes, alkenes / combustible gases, smoke), and analyzed by an electronic nose. Please refer to Figures 6 - 7 , indicating that there are significant differences in the volatile gas components between the samples of stabilizer 1 and stabilizer 3 formulations, and they can be effectively identified by the electronic nose.

[0087] Stability tests were carried out on samples with different stability formulations:

[0088] Stabilizers 1 and 3 are hereinafter referred to as samples 1 and 3 respectively. Please refer to Figures 8 - 10 , according to the particle size, Zeta potential and stability results of samples 1 and 3 detected:

[0089] The particle sizes of samples 1 and 3 are relatively concentrated. Among them, the average particle size of sample 1 is 0.176 μm, and the average particle size of sample 3 is 0.231 μm. It can be concluded that the average particle sizes of samples 1 and 3 are both relatively small.

[0090] Zeta potential can reflect the stability of pandan coconut juice beverage. The higher the absolute value, the more stable the system, that is, dissolution or dispersion can resist aggregation. According to the Zeta potential results, the absolute value of Zeta potential of sample 1 > sample 3.

[0091] A multi-light scattering stability analyzer was used to systematically analyze samples 1 and 3 of pandan coconut juice. According to different time periods, a comprehensive scan was carried out on the pandan coconut juice in the sample cell from the bottom to the top, and the obtained data were incrementally marked from blue to red in the order of the number of scans. In the data processing stage, the transmitted light or backscattered light data was set as the reference mode to generate a detailed spectrogram. Please refer to Figure 11 . After in-depth analysis of the spectrogram, it was found that the increase in light intensity at the top of samples 1 and 3 increased significantly. The results show that in terms of stability, the instability of samples 1 and 3 is mainly manifested as an obvious floating and stratification phenomenon at the top. Please refer to Table 2 for the stability kinetic index.

[0092] Table 2 Stability kinetic index

[0093] Measurement 25℃ TSI (Overall) Sample 1 0.60 Sample 3 0.93

[0094] The comprehensive change range of the concentration and particle size during the entire placement time. The larger the change range, the larger the stability kinetic index (TSI), and the more unstable the system. The results show that Sample 1 is the most stable, followed by Sample 3.

[0095] The absolute value of the light intensity represents the initial difference of the sample. The absolute value of the light intensity is affected by the particle size, concentration, and composition of the sample, while the change value of the light intensity represents the ability of particle aggregation. When the change value of the light intensity is less than 0.2%, it indicates very stable. When the change value of the light intensity is between 0.2% and 0.5%, it indicates medium stability. When the change value of the light intensity is greater than 0.8%, it indicates significant instability. The absolute values of the light intensity changes of the two samples are both around 0.2, indicating good stability and no obvious particle aggregation phenomenon. Please refer to Table 3.

[0096] Table 3 Light intensity change values

[0097] Measurement Light intensity change value at 25℃ Sample 1 -0.08％ Sample 3 0.13％

[0098] The dispersion uniformity index characterizes the degree of dispersion uniformity of each dispersed component in the sample in the system. The larger the dispersion uniformity index, the worse the dispersion uniformity degree of the sample. The dispersion uniformity of the two samples is good. Please refer to Table 4.

[0099] Table 4 Dispersion uniformity index

[0100] Measurement Uniformity index at 25℃ Sample 1 0.08 Sample 3 0.08

[0101] Based on the above sensory evaluation scores, electronic nose analysis, and stability test analysis of the two stabilizer samples, it shows that Stabilizer 1 has a better effect on the stability and flavor quality of this pandan coconut juice product.

[0102] For Stabilizer 1, single-factor experiments were conducted on four factors: coconut meat content, pandan content, white sugar content, and casein content. Five levels were selected for each factor: coconut meat content (6.5%, 7.0%, 7.5%, 8.0%, 8.5%), pandan content (0.15%, 0.30%, 0.6%, 1.2%, 2.4%), white sugar content (5.5%, 6.0%, 6.5%, 7.0%, 7.5%), casein content (0.25%, 0.30%, 0.35%, 0.40%, 0.45%). Using sensory evaluation as the main measurement index, 21 people were invited to taste and score through a scoring form. After removing the highest and lowest scores, the average score was calculated. The results of the coconut meat content, pandan content, white sugar content, and casein content on the pandan coconut juice score are as Figures 12 - 15As shown. The optimal coconut meat content, pandan content, white granulated sugar content, and casein content were determined to be 7.5%, 0.6%, 6.5%, and 0.4% in sequence.

[0103] For this stabilizer 1, considering the two factors of product taste and cost control, the following 6 formulations were screened to determine their sensory scores and quality stability. The formulations are shown in Table 5.

[0104] Table 5 Formulations of six groups of samples

[0105] Observe the changes in the stable state of the samples at different times (0h, 1h, 3h, 4h, 5h, 24h, 72h) after opening the lid. Please refer to Figures 16 - 22 .

[0106] The stability of the samples was detected at different times after opening the lid. All formulations could maintain a high stable state within 24h after opening the lid. At 5h, slight floating and delamination occurred in the three formulations with high pandan content (Samples 1, 2, 3). At 24h, white foams appeared in the floating layer of Sample 6 among the three formulations with low pandan content. At 72h, all formulation samples showed a non-uniform state except for Sample 5, indicating that Sample 5 had better stability.

[0107] Six samples, namely Samples 1, 2, 3, 5, 6, and 7, were analyzed by an electronic nose-sensory analyzer. Please refer to Figures 23 - 24 . It shows that there are significant differences in the volatile gas components among the six samples, and they can be effectively identified by the electronic nose.

[0108] The sensory scores of the six samples were evaluated. 21 people were invited to taste and score through a scoring form. After removing the highest and lowest scores, the average scores of the 6 samples were 76.31, 75.83, 70.92, 86.41, 84.67, and 69.55 in sequence. It indicates that the taste quality and stability of Sample 5 are the best.

[0109] Based on the above, Sample 5 is the optimal formulation of pandan coconut juice, and the test results of its physical and chemical indexes are shown in Table 6.

[0110] Table 6 Test results of the physical and chemical indexes of the product

[0111]

[0112] As shown in Table 6, the soluble solid content of the pandan coconut juice was measured to be 9.1%, the protein was 0.58%, and the pH was 7.0. All the above results meet the national standards.

[0113] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a pandan coconut juice beverage, characterized in that, It includes the following steps: S1. Preparation of coconut milk; S2. Pretreatment of fresh pandan leaves with enzyme preparation and preparation of pandan pulp; S3. Compound and emulsification operation; S4. Homogenization and sterilization.

2. The preparation method of the pandan coconut juice beverage according to claim 1, characterized in that, The preparation method of coconut milk in S1 is as follows: Manually break the shell to obtain fresh coconut meat, remove the black skin on the surface, and rinse with cold water until there is no impurity; After cutting the coconut meat into pieces, place it in a microwave device for microwave treatment with a power of 500 - 800W and a time of 1 - 2 minutes; After microwave treatment, soak the coconut meat in 80°C hot water for 2 - 3 minutes to soften the tissue, then put it into a blender, and make pulp according to the ratio of coconut meat to hot water of 1:

1. At the same time, turn on the ultrasonic auxiliary device with a frequency of 20 - 40kHz and a power of 200 - 400W, and perform ultrasonic treatment during pulping for 5 - 10 minutes to obtain crude coconut milk; Squeeze and separate the coconut milk and fiber through a 200 - mesh filter bag, collect the initially filtered coconut milk, re - pulp the remaining coconut flakes, add 80°C hot water with a ratio of 1:1 to the coconut flakes, and pass through 200 - mesh to fully extract the active ingredients; Combine the coconut milk filtered twice to obtain coconut milk.

3. The preparation method of the pandan coconut juice beverage according to claim 2, characterized in that, The specific method of treating fresh pandan leaves with enzyme preparation in S2 is as follows: Uniformly apply 1wt% sodium bicarbonate solution on the fresh pandan leaves. After the leaf surface is uniformly attached, put it into the refrigerator and freeze for 24h to rupture the cell membrane of the leaves; Cut the fresh pandan leaves, blanch the pandan leaf segments with 80°C hot water, and use ultrasonic technology to treat the pandan leaf segments during blanching. The ultrasonic power is 120W, and the ultrasonic treatment is for 20 - 30min. Cool the blanched pandan leaves, and add an enzyme preparation composed of tannase and polyphenol oxidase with an addition ratio of 2:1 at a temperature of 30 - 60°C and a pH of 5 - 6. The concentration of tannase is 0.2 - 1.5U / mL, the concentration of polyphenol oxidase is 0.1 - 0.75U / mL, the treatment time is 0.5 - 1.0h, and the ratio of the mixed enzyme solution to the pandan leaves is 1:10 - 1:

4.

4. The preparation method of the pandan coconut juice beverage according to claim 3, wherein, The preparation method of pandan pulp in S2 is as follows: Mix the pandan leaf segments pretreated with the compound enzyme preparation and fresh mint leaves according to a weight ratio of 9:1, put them into a high - speed juicer for pressing, the rotation speed of the high - speed juicer > 10000r / min, and filter with 200 - mesh after pressing to obtain pandan pulp with a unique flavor.

5. The preparation method of the pandan coconut juice beverage according to claim 4, characterized in that, The steps of compound and emulsification operation in S3 are as follows: First, pre - emulsify 7 - 12 parts of coconut milk for 1 minute; Secondly, pre - dissolve the following auxiliary materials with 80°C hot water in sequence: 0.3 - 0.35 parts of stabilizer, 0.3 - 0.5 parts of sodium caseinate, 5 - 7 parts of granulated sugar, 0.5 - 1 part of fructooligosaccharide, 0.02 - 0.05 parts of baking soda, and pre - emulsify for 1 minute; And add them to the pre - emulsified coconut milk in sequence, continue to mix and emulsify at 80°C for 1 - 2 minutes, add 0.5 - 1 part of pandan pulp, add pure water to make up to 100 parts, and emulsify for 6min; Control the concentration consistency by the amount of added water so that the content of coconut meat in the product accounts for 70 - 120g / L.

6. The preparation method of the pandan coconut juice beverage according to claim 5, characterized in that, The dietary fiber is fructooligosaccharide in water - soluble dietary fiber.

7. The preparation method of the pandan coconut juice beverage according to claim 5, characterized in that, The stabilizer is an emulsifying stabilizer composed of 0.1350 - 0.1575 parts of mono- and diglycerol fatty acid esters, 0.090 - 0.105 parts of sodium stearoyl lactate, 0.0330 - 0.0385 parts of maltodextrin, 0.018 - 0.021 parts of sodium citrate, 0.006 - 0.007 parts of xanthan gum, 0.006 - 0.007 parts of guar gum, 0.006 - 0.007 parts of sodium alginate, and 0.006 - 0.007 parts of sodium carboxymethyl cellulose.

8. The preparation method of the pandan coconut juice beverage according to claim 7, characterized in that, The specific steps of homogenization and sterilization in S4 are as follows: adopt a two-stage gradient homogenization process: 30 MPa for the first time and 35 MPa for the second time to ensure that the particle size is ≤ 2 μm; finally, adopt ultra-high temperature instantaneous sterilization, UHT, at 139 - 141 °C for 9 - 15 s, and quickly cool it to below 25 °C for filling to obtain the pandan coconut natural beverage.

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