Gelatin fruit pulp jelly and preparation method thereof

Abstract

The invention discloses gelatin fruit pulp jelly and a preparation method thereof, and belongs to the technical field of food. The gelatin fruit pulp jelly is prepared from the following components in parts by mass: 35 to 65 parts of water, 30 to 60 parts of NFC fruit pulp, 0 to 4.0 parts of gelatin, 0.1 to 0.5 part of konjaku flour, 0.05 to 0.3 part of locust bean gum and 0.1 to 5 parts of mulberry polyphenol extract. The mulberry polyphenol extract is prepared by combining ethanol ultrasonic-assisted extraction with macroporous resin purification and low-temperature spray drying. The pH (Potential of Hydrogen) value of the gelatin fruit pulp jelly is 3.0 to 4.5. The gelatin fruit pulp jelly is smooth in texture, and the natural flavor of fruits can be well kept. And the gel system disclosed by the invention has high gel stability and antioxidant activity in an acidic system.

Description

Technical Field

[0001] This invention belongs to the field of food technology, and in particular relates to a gelatin fruit jelly and its preparation method. Background Technology

[0002] Traditional jellies often use high-sugar syrups and synthetic colloids as raw materials, but this syrup and gel system easily masks the natural flavor of the fruit. NFC (Not From Concentrate) syrup is a non-concentrated juice, made by pressing, sterilizing, and directly bottling fruit juice, thus preserving the original juice's nutrients and flavor to a greater extent. Because fruits contain various organic acids, such as citric acid, malic acid, and tartaric acid, NFC syrup is highly acidic. Conventional synthetic colloids or gelatin alone are difficult to adapt to this low-sugar, high-acid NFC syrup system, easily leading to problems such as low gel strength and high water separation.

[0003] Furthermore, mulberries are rich in polyphenols such as anthocyanins and resveratrol, but traditional hot water extraction methods easily lead to the degradation of active ingredients in acidic jelly systems. Existing technologies typically employ supercritical CO2 extraction, which, while preserving activity, is costly and does not resolve compatibility issues with gelatin-konjac gum systems.

[0004] Therefore, there is a need for a fruit jelly that can retain the nutrients of mulberries, preserve the natural flavor of the fruit, and be compatible with acidic gel systems. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a gelatin fruit jelly and its preparation method. The gelatin fruit jelly of the present invention has a smooth texture, excellent flavor and stable gel system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a gelatin fruit jelly, comprising the following components in parts by weight: 35-65 parts water, 30-60 parts NFC fruit pulp, 2.0-4.0 parts gelatin, 0.1-0.5 parts konjac flour, 0.05-0.3 parts locust bean gum, and 0.5-3 parts mulberry polyphenol extract; the pH value of the gelatin fruit jelly is 3.0-4.5; the mulberry polyphenol extract is prepared by ethanol ultrasonic-assisted extraction combined with macroporous resin purification and low-temperature spray drying.

[0008] Preferably, the weight ratio of gelatin to konjac powder is (6-10):1.

[0009] Preferably, the NFC fruit pulp has a soluble solids content of ≥12% and a pH of 3-4. The NFC fruit pulp can provide a natural flavor and an acidic environment.

[0010] Preferably, the gelatin is in granular form and has a gel strength (1% aqueous solution, 25°C) ≥ 200 Blooms.

[0011] Preferably, the viscosity of the konjac powder is ≥15000mPa·s.

[0012] Preferably, the purity of the locust bean gum is ≥85% and the particle size is ≤100 mesh.

[0013] Furthermore, the gelatin fruit jelly also includes a pH adjuster selected from lemon juice and citric acid.

[0014] Preferably, the pH value of the gelatin fruit jelly is 3.5-4.

[0015] Preferably, the pH value of the gelatin fruit jelly is 3.8±0.1.

[0016] Preferably, the gelatin fruit jelly also includes 8-14 parts of sugar, said sugar being white sugar, to supplement the sweetness.

[0017] Preferably, the NFC fruit pulp is selected from at least one of NFC passion fruit pulp, NFC blueberry pulp, NFC mango pulp, and NFC mulberry pulp.

[0018] Preferably, the mulberry polyphenol extract has a mass fraction of 0.5-3 parts and a polyphenol content of ≥50%.

[0019] The mulberry polyphenol extract exhibits an anthocyanin retention rate of >90% after 30 days of light exposure in an acidic gel system with a pH of 3.0-4.5.

[0020] Furthermore, the preparation method of the mulberry polyphenol extract specifically includes the following steps:

[0021] (1) Remove the stems from the fresh mulberries, pulp them, and then sieve them to obtain mulberry juice;

[0022] (2) Add 50-70% ethanol solution to mulberry juice at a material-to-liquid ratio of (1:5)-(1:10), and ultrasonically extract at 50-60℃ for 20-40 min to obtain mulberry ultrasonic extract.

[0023] (3) Centrifuge the ultrasonic extract of mulberry, take the supernatant and remove it with AB-8 macroporous resin to obtain mulberry eluent;

[0024] (4) The mulberry eluent was concentrated and spray-dried at a low temperature of ≤160℃ to obtain a mulberry polyphenol extract with a polyphenol content of ≥50%.

[0025] Preferably, in step (2), the ethanol solution also includes 0.1% citric acid by mass.

[0026] Preferably, the gelatin fruit jelly also includes 0.01-0.03 parts of ε-polylysine hydrochloride (food grade).

[0027] The ε-polylysine hydrochloride is positively charged and can work with polyphenols to disrupt microbial cell membranes, exhibiting a synergistic antibacterial effect. Combined with the sterilization process, it can further extend the shelf life while maintaining the stability of anthocyanins.

[0028] On the other hand, the present invention also discloses a method for preparing gelatin fruit jelly, which includes the following steps:

[0029] S1. Gelatin and a portion of water are swollen in a water bath at 60±2℃ for 20±5 minutes, stirred until completely dissolved, filtered, and a gelatin solution is obtained; the mass of the portion of water accounts for 20% of the total mass of water.

[0030] S2. Mix konjac powder with locust bean gum, add the remaining water and sugar, and stir evenly at 75±3℃ to obtain a mixed colloidal solution.

[0031] S3. Mix the gelatin solution and the mixed colloidal solution at 65±2℃, and homogenize to obtain a compound colloidal solution; add NFC fruit pulp and mulberry polyphenol extract preheated to 50±2℃ to the compound colloidal solution, stir evenly, and add pH adjuster to pH 3.0-4.5.

[0032] S4. After filling, sealing, sterilization, and cooling to below 25°C, gelatin fruit jelly is obtained.

[0033] Preferably, in step S1, the swelling time is 20±5 min, and the stirring is intermittent.

[0034] Preferably, the intermittent stirring is performed with a 5-second stirring interval followed by a 2-second interval.

[0035] Preferably, in step S1, a 100-mesh sieve is used for filtration to remove impurities.

[0036] Furthermore, in step S2, the stirring parameters are: rotation speed 500±50 rpm, time 15±3 min; the stirring is magnetic stirring.

[0037] Preferably, the homogenization parameters are: rotation speed 3000±50 rpm, time 1-3 min.

[0038] Preferably, in step S3, the stirring speed is 200±10 rpm and the stirring time is 3-8 min.

[0039] Preferably, step S3 further includes filtering the NFC pulp to remove the seeds before preheating.

[0040] Preferably, the sterilization is performed by water bath at 85±2℃ for 8-15 minutes.

[0041] Furthermore, the preparation method of the NFC fruit pulp includes the following steps: washing, peeling, pitting, pulping, aseptically filling, then performing low-temperature ultra-high pressure sterilization (HPP), and storing at -18℃.

[0042] The advantages of this invention compared to the prior art are:

[0043] The present invention uses NFC fruit pulp to prepare jelly, which can provide the natural flavor of fruit. By compounding gelatin, konjac powder and locust bean gum in a specific ratio, a stable gel system can be formed in the highly acidic fruit pulp system, so that the gelatin fruit jelly has a smooth texture and can well maintain the natural flavor. By compounding the components, the resulting gelatin fruit jelly has a smooth texture, high gel strength and is not easy to separate into water.

[0044] This invention combines mulberry polyphenol extract with NFC fruit pulp to enhance DPPH free radical scavenging rate; and the anthocyanins in the mulberry polyphenol extract can bind with the gelatin-konjac gum network through hydrogen bonds and hydrophobic interactions to form a stable encapsulation structure under pH 3.8±0.2 conditions, thereby prolonging the anthocyanin half-life.

[0045] This invention uses ultrasonic-assisted extraction combined with macroporous resin purification and low-temperature spray drying to prepare mulberry polyphenol extract, which can ensure the yield of mulberry polyphenols while maintaining low cost. Detailed Implementation

[0046] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0048] In addition, unless otherwise specified, all percentages mentioned in this invention are mass percentages; all parts are mass parts.

[0049] To better understand the technical content of the present invention, the technical solution of the present invention will be further introduced and explained below with reference to specific embodiments.

[0050] Example 1

[0051] A gelatin fruit jelly comprising the following components in parts by weight: 50 parts NFC passion fruit pulp, 34.5 parts water, 8 parts white sugar, 3 parts gelatin, 0.3 parts konjac powder, 0.2 parts locust bean gum, and 3 parts mulberry polyphenol extract; the gelatin fruit jelly has a pH of 3.8; and the NFC passion fruit pulp has a pH of 3.2.

[0052] This embodiment also discloses a method for preparing the above-mentioned gelatin fruit jelly, which includes the following steps:

[0053] S1. Soak gelatin and a portion of water in a 60°C water bath for 10 minutes, stir until completely dissolved, filter through a 100-mesh sieve to remove impurities, and obtain a gelatin solution; wherein, the mass of the water portion accounts for 20% of the total mass of water.

[0054] S2. Mix konjac powder and locust bean gum, add the remaining water and sugar, and magnetically stir at 500 rpm for 15 minutes at 75℃ to obtain a mixed colloidal solution.

[0055] S3. After filtering the NFC passion fruit pulp through a 40-mesh sieve to remove the seeds, preheat it to 50°C and set aside. Mix the gelatin solution and the mixed colloidal solution at 65°C, homogenize at 3000 rpm for 2 minutes, then add the mulberry polyphenol extract and the preheated NFC passion fruit pulp, and stir at 200 rpm for 5 minutes to obtain the jelly liquid.

[0056] S4. Fill the jelly liquid into PP cups (50g / cup), seal and sterilize in a water bath (80℃ / 10min), then cool to below 25℃ to obtain gelatin fruit jelly.

[0057] Specifically, the preparation method of mulberry polyphenol extract in this embodiment includes the following steps:

[0058] (1) Take 10kg of fresh mulberries (variety "Black Pearl"), remove the stems, pulp them, and filter the seeds through a 40-mesh sieve to obtain mulberry juice;

[0059] (2) Add 70L of 60% ethanol solution to mulberry juice and extract by ultrasonication (40kHz, 200W) at 55℃ for 30min to obtain mulberry ultrasonic extract.

[0060] (3) The mulberry ultrasonic extract was centrifuged at 4000 rpm for 10 min, and the supernatant was passed through an AB-8 resin column. After removing impurities with 30% ethanol solution, it was eluted with 50% ethanol solution to obtain mulberry eluent.

[0061] (4) The mulberry eluent was concentrated under reduced pressure to a solid content of 10%, and spray-dried (air intake 160℃) to obtain a brownish-red powder (mulberry polyphenol extract).

[0062] Specifically, the ethanol solution also contains 0.1% citric acid.

[0063] Example 2

[0064] A gelatin fruit jelly comprising the following components in parts by weight: 39.15 parts water, 45 parts NFC blueberry pulp, 10 parts white sugar, 3.5 parts gelatin, 0.2 parts konjac powder, 0.15 parts locust bean gum and mulberry polyphenol extract; the gelatin fruit jelly has a pH of 3.8; the NFC blueberry pulp has a pH of 3.5.

[0065] This embodiment also discloses a method for preparing the above-mentioned gelatin fruit jelly, which includes the following steps:

[0066] S1. Soak gelatin and a portion of water in a water bath at 62°C for 15 minutes, stir until completely dissolved, filter through a 100-mesh sieve to remove impurities, and obtain a gelatin solution; wherein, the mass of the water accounts for 20% of the total mass of water.

[0067] S2. Mix konjac powder and locust bean gum, add the remaining water and sugar, and magnetically stir at 450 rpm for 18 minutes at 78℃ to obtain a mixed colloidal solution.

[0068] S3. After filtering the NFC blueberry pulp through a 40-mesh sieve to remove the seeds, preheat it and the mulberry polyphenol extract to 52°C respectively, and set aside. Mix the gelatin solution and the mixed colloidal solution at 67°C, homogenize at 3050 rpm for 1 min, add the preheated NFC blueberry pulp and mulberry polyphenol extract, and stir at 190 rpm for 8 min to obtain the jelly liquid.

[0069] S4. Fill the jelly liquid into PP cups (50g / cup), seal and sterilize in a water bath (83℃ / 8min), then cool to below 25℃ to obtain gelatin fruit jelly.

[0070] Specifically, the preparation method of mulberry polyphenol extract in this embodiment includes the following steps:

[0071] (1) Take 10kg of fresh mulberries (variety "Black Pearl"), remove the stems, pulp them, and filter the seeds through a 40-mesh sieve to obtain mulberry juice;

[0072] (2) Add 50L of 70% ethanol solution to mulberry juice and extract it by ultrasonic extraction at 60℃ (40kHz, 200W) for 20min to obtain mulberry ultrasonic extract.

[0073] (3) The mulberry ultrasonic extract was centrifuged at 4000 rpm for 10 min, and the supernatant was passed through an AB-8 resin column. After removing impurities with 30% ethanol solution, it was eluted with 50% ethanol solution to obtain mulberry eluent.

[0074] (4) The mulberry eluent was concentrated under reduced pressure to a solid content of 10%, and spray-dried (air inlet 150℃) to obtain a brownish-red powder (mulberry polyphenol extract).

[0075] Example 3

[0076] A gelatin fruit jelly comprises the following components in parts by weight: 49 parts water, 40 parts NFC mango puree, 8 parts white sugar, 2.5 parts gelatin, 0.4 parts konjac powder, 0.1 parts locust bean gum, and 5 parts mulberry polyphenol extract; the pH value of the gelatin fruit jelly is 3.5; the pH value of the NFC mango puree is 3.2.

[0077] This embodiment also discloses a method for preparing the above-mentioned gelatin fruit jelly, which includes the following steps:

[0078] S1. Soak gelatin and a portion of water in a water bath at 58°C for 25 minutes, stir until completely dissolved, filter through a 100-mesh sieve to remove impurities, and obtain a gelatin solution; wherein, the mass of the water portion accounts for 20% of the total mass of water.

[0079] S2. Mix konjac powder and locust bean gum, add the remaining water and sugar, and magnetically stir at 550 rpm for 12 minutes at 72°C to obtain a mixed colloidal solution.

[0080] S3. After filtering the NFC mango puree through a 40-mesh sieve to remove the seeds, preheat it with mulberry polyphenol extract to 48°C and set aside. Mix the gelatin solution and the mixed colloidal solution at 63°C, homogenize at 2950 rpm for 3 minutes, then add the preheated NFC mango puree and mulberry polyphenol extract, and stir at 210 rpm for 3 minutes to obtain the jelly liquid.

[0081] S4. Fill the pH-adjusted jelly solution into PP cups (50g / cup), seal and sterilize in a water bath (77℃ / 12min), then cool to below 25℃ to obtain gelatin fruit jelly.

[0082] Specifically, the preparation method of mulberry polyphenol extract in this embodiment includes the following steps:

[0083] (1) Take 10kg of fresh mulberries (variety "Black Pearl"), remove the stems, pulp them, and filter the seeds through a 40-mesh sieve to obtain mulberry juice;

[0084] (2) Add 100L of 50% ethanol solution to mulberry juice and extract by ultrasonication (40kHz, 200W) at 50℃ for 40min to obtain mulberry ultrasonic extract.

[0085] (3) The mulberry ultrasonic extract was centrifuged at 4000 rpm for 10 min, and the supernatant was passed through an AB-8 resin column. After removing impurities with 30% ethanol solution, it was eluted with 50% ethanol solution to obtain mulberry eluent.

[0086] (4) The mulberry eluent was concentrated under reduced pressure to a solid content of 10%, and spray-dried (air inlet 120℃) to obtain a brownish-red powder (mulberry polyphenol extract).

[0087] Example 4

[0088] A gelatin fruit jelly comprises the following components in parts by weight: 44.4 parts water, 40 parts NFC citrus pulp, 14 parts white sugar, 3.2 parts gelatin, 0.25 parts konjac flour, 0.15 parts locust bean gum, and 2 parts mulberry polyphenol extract; the pH value of the gelatin fruit jelly is 3.4; the pH value of the NFC citrus pulp is 3.0.

[0089] In this embodiment, the preparation methods of gelatin fruit jelly and mulberry polyphenol extract are the same as in Example 1.

[0090] Example 5

[0091] A gelatin fruit jelly comprises the following components in parts by weight: 55.45 parts water, 30 parts NFC mango puree, 12 parts white sugar, 2 parts gelatin, 0.5 parts konjac powder, 0.05 parts locust bean gum, and 0.1 parts mulberry polyphenol extract; the gelatin fruit jelly has a pH of 4.0; and the NFC mango puree has a pH of 3.6.

[0092] This embodiment also discloses a method for preparing the above-mentioned gelatin fruit jelly, which includes the following steps:

[0093] S1. Soak gelatin and a portion of water in a water bath at 58°C for 25 minutes, stir until completely dissolved, filter through a 100-mesh sieve to remove impurities, and obtain a gelatin solution; wherein, the mass of the water portion accounts for 20% of the total mass of water.

[0094] S2. Mix konjac powder and locust bean gum, add the remaining water and sugar, and magnetically stir at 550 rpm for 12 minutes at 72°C to obtain a mixed colloidal solution.

[0095] S3. After filtering the NFC mango puree through a 40-mesh sieve to remove the seeds, preheat it and the mulberry polyphenol extract to 48°C respectively, and set aside. Mix the gelatin solution and the mixed colloidal solution at 63°C, homogenize at 2950 rpm for 3 minutes, add the preheated NFC mango puree and mulberry polyphenol extract, and stir at 210 rpm for 3 minutes to obtain the jelly liquid.

[0096] S4. Fill the jelly liquid into PP cups (50g / cup), seal and sterilize in a water bath (77℃ / 12min), then cool to below 25℃ to obtain gelatin fruit jelly.

[0097] Specifically, the preparation method of mulberry polyphenol extract in this embodiment is the same as in Example 1.

[0098] Example 6

[0099] A gelatin fruit jelly comprises the following components in parts by weight: 35.4 parts water, 60 parts NFC mango puree, 4.0 parts gelatin, 0.1 parts konjac powder, 0.3 parts locust bean gum, 0.2 parts citric acid solution, and 3 parts mulberry polyphenol extract; the gelatin fruit jelly has a pH of 3.8; the NFC mango puree has a pH of 3.6; and the citric acid solution has a mass concentration of 10%.

[0100] This embodiment also discloses a method for preparing the above-mentioned gelatin fruit jelly, which includes the following steps:

[0101] S1. Soak gelatin and a portion of water in a water bath at 58°C for 25 minutes, stir until completely dissolved, filter through a 100-mesh sieve to remove impurities, and obtain a gelatin solution; wherein, the mass of the water portion accounts for 20% of the total mass of water.

[0102] S2. Mix konjac powder and locust bean gum, add the remaining water, and magnetically stir at 550 rpm for 12 minutes at 72°C to obtain a mixed colloidal solution.

[0103] S3. After filtering the NFC mango puree through a 40-mesh sieve to remove the seeds, preheat it and the mulberry polyphenol extract to 48°C respectively, and set aside. Mix the gelatin solution and the mixed colloidal solution at 63°C, homogenize at 2950 rpm for 3 minutes, then add the preheated NFC mango puree and mulberry polyphenol extract, and stir at 210 rpm for 3 minutes to obtain the jelly liquid. Add 10% citric acid solution to the jelly liquid to adjust the pH value.

[0104] S4. Fill the pH-adjusted jelly solution into PP cups (50g / cup), seal and sterilize in a water bath (77℃ / 12min), then cool to below 25℃ to obtain gelatin fruit jelly.

[0105] Specifically, the preparation method of mulberry polyphenol extract in this embodiment is the same as in Example 1.

[0106] Example 7

[0107] A gelatin fruit jelly comprises the following components in parts by weight: 38 parts water, 45 parts NFC mulberry pulp, 3.2 parts gelatin, 0.25 parts konjac flour, 0.15 parts locust bean gum, and 2 parts mulberry polyphenol extract; the gelatin fruit jelly has a pH of 3.6; and the NFC mulberry pulp has a pH of 3.3.

[0108] This embodiment also discloses a method for preparing the above-mentioned gelatin fruit jelly, which includes the following steps:

[0109] S1. Soak gelatin and a portion of water in a water bath at 58°C for 10 minutes, stir until completely dissolved, filter through a 100-mesh sieve to remove impurities, and obtain a gelatin solution; wherein, the mass of the water portion accounts for 20% of the total mass of water.

[0110] S2. Mix konjac powder and locust bean gum, add the remaining water and sugar, and magnetically stir at 500 rpm for 15 minutes at 75℃ to obtain a mixed colloidal solution.

[0111] S3. After filtering the NFC mulberry pulp through a 40-mesh sieve to remove the seeds, preheat it to 50°C and set aside. Mix the gelatin solution and the mixed colloidal solution at 65°C, homogenize at 3000 rpm for 2 minutes, then add the mulberry polyphenol extract and the preheated NFC mulberry pulp, and stir at 200 rpm for 5 minutes to obtain the jelly liquid.

[0112] S4. Fill the jelly liquid into PP cups (50g / cup), seal and sterilize in a water bath (83℃ / 15min), then cool to below 25℃ to obtain gelatin fruit jelly.

[0113] Specifically, the preparation method of mulberry polyphenol extract in this embodiment is the same as in Example 1.

[0114] Example 8

[0115] The gelatin fruit jelly of this embodiment, based on Example 7, also includes 0.02 parts of ε-polylysine hydrochloride.

[0116] Specifically, the preparation method of gelatin fruit jelly includes the following steps:

[0117] S1. Soak gelatin and a portion of water in a water bath at 60°C for 20 minutes, stir until completely dissolved, filter through a 100-mesh sieve to remove impurities, and obtain a gelatin solution; wherein, the mass of the water accounts for 20% of the total mass of water.

[0118] S2. Mix konjac powder and locust bean gum, add the remaining water, and magnetically stir at 500 rpm for 15 minutes at 75°C to obtain a mixed colloidal solution.

[0119] S3, after filtering the NFC mulberry pulp through a 40-mesh screen, preheat it to 50℃ and set aside; mix the gelatin solution and the mixed colloidal solution at 65℃, homogenize at 3000rpm for 2min, then add the mulberry polyphenol extract powder and the preheated NFC mulberry pulp, and stir at 200rpm for 5min to obtain the jelly liquid; add ε-polylysine hydrochloride (food grade) to the jelly liquid with a material temperature <60℃ and add citric acid to adjust the pH value;

[0120] S4. Fill the jelly liquid into PP cups (50g / cup), seal and sterilize in a water bath (85℃ / 15min), then cool to below 25℃ to obtain gelatin fruit jelly.

[0121] Specifically, the preparation method of mulberry polyphenol extract in this embodiment is the same as in Example 1. To illustrate the technical effects of the present invention, the following tests / verifications were conducted based on the above embodiments:

[0122] (I) Anthocyanin retention rate and polyphenol content test

[0123] Based on the above, comparative examples 1-3 are set as follows:

[0124] Comparative Example 1

[0125] The only difference between this comparative example and the mulberry polyphenol extract of Example 1 is that macroporous resin purification was not performed.

[0126] The preparation method of mulberry polyphenol extract in this comparative example includes the following steps:

[0127] (1) Take 10kg of fresh mulberries (variety "Black Pearl"), remove the stems, pulp them, and filter the seeds through a 40-mesh sieve to obtain mulberry juice;

[0128] (2) Add 100L of 50% ethanol solution to mulberry juice and extract by ultrasonication (40kHz, 200W) at 50℃ for 40min to obtain mulberry ultrasonic extract.

[0129] 3) Centrifuge the mulberry ultrasonic extract at 4000 rpm for 10 min. Remove impurities from the supernatant with 30% ethanol solution and then elute with 50% ethanol solution to obtain mulberry eluent.

[0130] (4) The mulberry eluent was concentrated under reduced pressure to a solid content of 10%, and spray-dried (air inlet 120℃) to obtain a brownish-red powder (mulberry polyphenol extract).

[0131] Comparative Example 2

[0132] The only difference between the preparation process of this comparative example and the mulberry polyphenol extract in Example 1 is that the spray drying temperature is 200°C.

[0133] Comparative Example 3

[0134] The only difference between this comparative example and Example 7 is that the mulberry polyphenol extract was extracted using conventional supercritical CO2 extraction.

[0135] The total phenolic content and anthocyanin content of the mulberry polyphenol extracts in Examples 1-3 and Comparative Examples 1-3 were determined according to GB / T 31740.2-2015, and the polyphenol retention rate after storage at 60℃ for 7 days was tested. The test results are shown in Table 1 below.

[0136] Table 1. Test results of total phenol content, anthocyanin content, and polyphenol retention rate in mulberry polyphenol extract.

[0137]

[0138]

[0139] As shown in Table 1, the mulberry polyphenol extract prepared by the method of the present invention has a total phenol content of ≥58% and anthocyanin content of ≥15%, and its polyphenol retention rate can be significantly improved after being stored at 60°C for 7 days compared with other methods.

[0140] To verify the technical effect of mulberry polyphenol extract in gelatin fruit jelly, the anthocyanin retention rate of gelatin fruit jelly from Example 7 and Comparative Examples 1-3 was detected by HPLC (30-day light experiment), and the total phenol content was detected by Folin-Ciocalteu method. The test results are shown in Table 2 below.

[0141] Table 2. Detection of anthocyanin retention rate and total phenolic content in gelatin fruit jelly

[0142] index Anthocyanin retention rate (%) Total phenol content (mgGAE / 100g) Example 7 92 85 Comparative Example 1 76.5 62.3 Comparative Example 2 68.2 58.7 Comparative Example 3 88.7 79.8

[0143] As shown in Table 2, the total phenol content of the mulberry polyphenol extract of the present invention can reach 85 mg GAE / 100g in the acidic gel system of the gelatin fruit jelly of the present invention, and the anthocyanin retention rate is maintained at more than 92%. However, the mulberry polyphenol extract prepared by the preparation methods of Comparative Examples 1-3 has reduced anthocyanin retention rate and total phenol content in the acidic gel system.

[0144] (II) Gel properties and sensory testing

[0145] 1) To illustrate the technical effects of the above embodiments of the present invention, the gelatin fruit jelly of the embodiments was subjected to performance tests, and its gel strength, water separation rate and sensory evaluation were tested respectively.

[0146] The gel strength was tested by puncture, using a probe with a P / 0.5 probe; the water separation rate was tested by storing the gelatin fruit jelly at 4°C for 30 days; the sensory evaluation method involved a 20-person tasting panel who scored the flavor release, refreshing taste, and appearance of the gelatin fruit jelly in each embodiment on a 10-point scale, and the average sensory score was taken.

[0147] The test results are shown in Table 3 below:

[0148] Table 3 Performance test results of the embodiments

[0149] gel strength (g) Water separation rate (%) Sensory rating Example 1 320 1.5 9.0 Example 2 300 2.0 8.5 Example 3 280 2.5 8.7 Example 4 310 1.8 8.6 Example 5 250 3.5 7.8 Example 6 350 2.8 8.0 Example 7 305 1.7 8.9 Example 8 318 1.5 9.1

[0150] 2) To illustrate the technical effects of the gel system of the present invention on water activity and flavor release, comparative examples 4 and 5 were set up based on Example 1 as follows:

[0151] Comparative Example 4

[0152] The only difference between this comparative example and Example 1 is that the gelatin content in this comparative example is 4.0 parts and it does not contain konjac powder or locust bean gum.

[0153] Comparative Example 5

[0154] The only difference between this comparative example and Example 1 is that the amount of gelatin in this comparative example is 3.0 parts, and 0.5 parts of carrageenan is used to replace konjac powder and locust bean gum.

[0155] Performance tests were conducted on Comparative Examples 4 and 5, using the same testing methods as in the embodiments. The test results are shown in Table 4 below.

[0156] Table 4 Performance test results of Example 1, Comparative Example 4 and Comparative Example 5

[0157]

[0158]

[0159] As shown in Table 4, when only gelatin is used, or when carrageenan is used to replace konjac flour and locust bean gum, the gel strength decreases significantly, the water separation rate increases significantly, the passion fruit flavor is poor, and the water activity increases. Furthermore, the jelly obtained by replacing konjac flour and locust bean gum with carrageenan has a heavier, stickier texture. Therefore, the gel system of this invention uses a compound of gelatin, konjac flour, and locust bean flour, which exhibits high gel strength, low water separation rate, and a rich passion fruit flavor in acidic systems. In addition, the gel compound system of this invention can form a dense gel network, limiting water activity (Aw≤0.85), which can achieve a certain degree of microbial inhibition.

[0160] 3) To further illustrate the technical effects of the proportions of each substance in the gel system of the present invention, comparative examples 6-14 are further set up based on Example 1 as follows:

[0161] Comparative Example 6

[0162] The only difference between this comparative example and Example 1 is that in this comparative example, the amount of gelatin is 1.5 parts, the amount of konjac powder is 0.3 parts, and the amount of locust bean gum is 0.2 parts.

[0163] Comparative Example 7

[0164] The only difference between this comparative example and Example 1 is that in this comparative example, the amount of gelatin is 5.0 parts, the amount of konjac powder is 0.1 parts, and the amount of locust bean gum is 0.1 parts.

[0165] Comparative Example 8

[0166] The only difference between this comparative example and Example 1 is that in this comparative example, the amount of gelatin is 3.0 parts, the amount of konjac powder is 0.8 parts, and the amount of locust bean gum is 0.2 parts.

[0167] Comparative Example 9

[0168] The only difference between this comparative example and Example 1 is that in this comparative example, the amount of gelatin is 3.0 parts, the amount of konjac powder is 0.2 parts, and the amount of locust bean gum is 0.5 parts.

[0169] Comparative Example 10

[0170] The only difference between this comparative example and Example 1 is that 0.3 parts of carrageenan are used instead of gelatin in this comparative example.

[0171] Comparative Example 11

[0172] The only difference between this comparative example and Example 1 is that 0.2 parts of gellan gum were used to replace gelatin in this comparative example, and the mass fraction of locust bean gum was 0.1 parts.

[0173] Comparative Example 12

[0174] The only difference between this comparative example and Example 1 is that 0.4 parts of pectin were used to replace gelatin in this comparative example, and the mass fraction of locust bean gum was 0.1 parts.

[0175] Comparative Example 13

[0176] The only difference between this comparative example and Example 1 is that 0.3 parts of xanthan gum are used instead of gelatin in this comparative example.

[0177] Comparative Example 14

[0178] The only difference between this comparative example and Example 1 is that 0.4 parts of sodium alginate were used to replace gelatin in this comparative example.

[0179] The performance of the above comparative examples was tested using the same method as the examples, and the test results are shown in Table 5 below.

[0180] Table 5 Performance test results of Example 1 and Comparative Examples 6-14

[0181]

[0182]

[0183] As shown in Tables 4 and 5 above, when the formulation or ratio of the gel system in the gelatin fruit jelly of this application is changed, it is impossible to balance the gel strength and water separation rate well in acidic NFC fruit pulp, and there are cost or flavor problems.

[0184] 4) To illustrate the effect of the mulberry polyphenol extract of the present invention on the gelling system in gelatin fruit jelly, comparative examples 15 and 16 were set up based on Example 7 as follows:

[0185] Comparative Example 15

[0186] The only difference between this comparative example and Example 7 is that mulberry polyphenol extract is not added in this comparative example.

[0187] Comparative Example 16

[0188] The only difference between this comparative example and Example 7 is that the amount of mulberry polyphenol extract added in this comparative example is increased to 6 parts.

[0189] Similarly, the gel strength and water separation rate of Example 7 and Comparative Examples 15 and 16 were tested according to the above method, and sensory scores and flavor descriptions were performed. At the same time, the DPPH free radical scavenging rate in their gelatin fruit jelly was tested, as shown in Table 6 below.

[0190] Table 6: Effects of Mulberry Polyphenol Extract on the Jelly Properties of Gelatin Fruit Berry

[0191]

[0192] As shown in Table 6, the mulberry polyphenol extract of the present invention can significantly improve the scavenging rate of DPPH free radicals, thereby removing the astringency in the jelly and enhancing its fruit flavor.

[0193] (III) Microbial stability testing

[0194] Accelerated aging conditions description:

[0195] Q 10 Value determination (temperature acceleration factor)

[0196] 25℃→37℃ (temperature difference 12℃)

[0197] Q 10 =t 25℃ / t 37℃ =3.5;

[0198] 25℃→45℃ (temperature difference 20℃)

[0199] Q 10 =t 25℃ / t 45℃ =3.8.

[0200] The shelf life was derived using the Arrhenius model:

[0201] Acceleration conditions at 45℃ (Q 10 =3.8), derive the shelf life at room temperature (25℃):

[0202]

[0203] Where ln(3.8) / ln(2.5) is the temperature acceleration factor; 7 days is the test duration at 45℃; and 30 is the unit conversion factor (converting weeks to days).

[0204] Similarly, when accelerated at 37°C, its shelf life is approximately 120 days.

[0205] 1) To further illustrate the gel stability of the present invention, the gelatin fruit jelly of Example 1 was subjected to stability testing, and its pH value after 30 days of storage and its microbial safety under accelerated aging conditions were tested.

[0206] In Example 1, the pH values ​​of the jelly before and after 30 days of storage were 3.8 and 3.7, respectively.

[0207] The detection methods and standards for microbial safety are as follows:

[0208] The experimental and control groups are set up as shown in Table 7 below:

[0209] Table 7 Experimental and control groups for microbial safety

[0210]

[0211] The testing indicators (based on GB 4789 series standards) are shown in Table 8 below.

[0212] Table 8 Microbiological safety testing indicators

[0213]

[0214] The specific testing steps are as follows:

[0215] Sample pretreatment: Open the jelly under sterile conditions, take 25g of sample and mix it with 225mL of sterile physiological saline, homogenize for 2min, and prepare a 1:10 sample homogenate.

[0216] Gradient dilution: Preparation of 10 -1 , 10 -2 , 10 -3 Diluent.

[0217] Inoculation and culture: Total bacterial count: Pour plate method, incubate at 36℃ for 48 h;

[0218] Coliform bacteria: MPN method, incubated at 36℃ for 24h;

[0219] Mold & Yeast: Spread coating method, incubate at 28℃ for 5 days;

[0220] Pathogenic bacteria: isolated using selective culture media and confirmed according to standard procedures.

[0221] The test results are shown in Table 9 below:

[0222] Table 9. Microbiological safety test results under accelerated aging conditions

[0223]

[0224] As can be seen from the pH value changes and microbial safety test results, the gelatin fruit jelly of the present invention has good pH stability. After being stored at 37°C for 14 days, the total number of colonies is ≤200 CFU / g and no pathogenic bacteria are detected, which meets the commercial sterility requirements (GB4789.26-2023). Therefore, its shelf life can reach 6 months at 25°C.

[0225] 2) To further illustrate the synergistic antibacterial effect of ε-polylysine hydrochloride and mulberry polyphenols, the gelatin fruit jelly from Examples 7 and 8 was subjected to accelerated aging tests to observe changes in colony count and sensory scores, and anthocyanin retention was tested according to the GB 37545-2019 test standard. The test results are shown in Table 10 below.

[0226] Table 10 Performance Comparison of Example 7 and Example 8

[0227]

[0228]

[0229] As shown in Table 10, ε-polylysine hydrochloride and mulberry polyphenols have a synergistic antibacterial effect. When used together, they can expand the diameter of the inhibition zone, enhance the antibacterial effect, and further extend the shelf life of gelatin pectin jelly.

[0230] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A gelatin-based fruit jelly, characterized in that, The product comprises the following components in parts by weight: 35-65 parts water, 30-60 parts NFC fruit pulp, 2.0-4.0 parts gelatin, 0.1-0.5 parts konjac flour, 0.05-0.3 parts locust bean gum, and 0.1-5 parts mulberry polyphenol extract; the pH value of the gelatin fruit jelly is 3.0-4.5; the mulberry polyphenol extract is prepared by ultrasonic-assisted extraction with ethanol combined with purification with macroporous resin and then low-temperature spray drying.

2. The gelatin fruit jelly as described in claim 1, characterized in that, The weight ratio of gelatin to konjac powder is (6-10):

1.

3. The gelatin fruit jelly as described in claim 1, characterized in that, It also includes a pH adjuster selected from lemon juice and citric acid.

4. The gelatin fruit jelly as described in claim 3, characterized in that, The pH value of the gelatin fruit jelly is 3.5-4.

0.

5. The gelatin fruit jelly as described in claim 1, characterized in that, The NFC pulp has a soluble solids content of ≥12% and a pH value of 3-4.

6. The gelatin fruit jelly as described in claim 1, characterized in that, It also includes 0.01-0.03 parts of food-grade ε-polylysine hydrochloride.

7. The gelatin fruit jelly as described in claim 1, characterized in that, The NFC fruit pulp is selected from at least one of NFC passion fruit pulp, NFC blueberry pulp, NFC mango pulp, and NFC mulberry pulp.

8. The gelatin fruit jelly as described in claim 1, characterized in that, The mulberry polyphenol extract has a polyphenol content of ≥50% and a mass fraction of 0.5-3 parts.

9. The gelatin fruit jelly as described in claim 8, characterized in that, The preparation method of the mulberry polyphenol extract specifically includes the following steps: (1) Remove the stems from the fresh mulberries, pulp them, and then sieve them to obtain mulberry juice; (2) Add 50-70% ethanol solution to mulberry juice at a material-to-liquid ratio of (1:5)-(1:10), and ultrasonically extract at 50-60℃ for 20-40 min to obtain mulberry ultrasonic extract. (3) Centrifuge the ultrasonic extract of mulberry, and use macroporous resin to remove the supernatant to obtain mulberry eluent; (4) The mulberry eluent was concentrated and spray-dried at low temperature under an air inlet temperature of ≤160℃ to obtain mulberry polyphenol extract.

10. A method for preparing gelatin fruit jelly as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Gelatin and a portion of water are swollen in a water bath at 60±2℃ for 20±5 minutes, stirred until completely dissolved, filtered, and a gelatin solution is obtained; the mass of the portion of water accounts for 20% of the total mass of water. S2. Mix konjac powder and locust bean gum, add the remaining water, and stir evenly at 75±3℃ to obtain a mixed colloidal solution. S3. Mix the gelatin solution and the mixed colloidal solution at 65±2℃, and homogenize to obtain a compound colloidal solution; add NFC fruit pulp and mulberry polyphenol extract preheated to 50±2℃ to the compound colloidal solution, stir evenly, and adjust the pH to 3.0-4.

5. S4. After filling, sealing, sterilization, and cooling to below 25°C, gelatin fruit jelly is obtained.

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