Preparation method of apple puree

Abstract

According to the preparation method of the apple puree provided by the invention, nitrogen is introduced during pulping, and the nitrogen can replace ascorbic acid to play an anti-oxidation role, so that when a consumer opens a can to eat the apple puree, the process of gradually oxidizing and browning from the white color of fresh fruits can be clearly seen in the puree; the process is close to the duration time of the gradual oxidation process of fresh fruit incisions, which is daily recognized by people, so that consumers can more intuitively see the additive-free effect of the fruit paste. Meanwhile, the thickening effect of the chemical thickening agent can be improved by adding nitrogen in the pulping stage, and xanthan gum in the thickening agent can be removed under the condition that the pulping time is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of fruit puree production, and in particular relates to a method for preparing apple puree. Background Technology

[0002] Apple puree is prone to oxidation during processing and storage, leading to darkening of color, decreased flavor, and loss of nutrients. Current anti-oxidation technologies primarily involve adding antioxidants such as ascorbic acid (vitamin C) and citric acid to inhibit oxidative browning. When antioxidants are added during the existing puree manufacturing process, their antioxidant effect is long-lasting. Even after prolonged exposure to air, the puree will not show signs of oxidative browning, whereas fresh fruit will show browning at the cut surface after being exposed to air for more than 30 minutes. Consumers with this experience can easily identify whether additives have been added to puree products. As living standards improve, consumers have higher demands for product quality, and the presence or absence of additives is becoming an important factor in their product selection. Summary of the Invention

[0003] In view of this, the present invention aims to propose a method for preparing apple puree, in which nitrogen gas is introduced during the pulping process for anti-oxidation treatment, thereby reducing the use of additives and improving product quality.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A method for preparing apple puree, comprising the following steps: S1. Pre-treatment: Wash, peel, core and cut the apples into pieces to obtain apple pulp pieces; S2. Steaming to inactivate enzymes: The apple pulp pieces are heated and steamed through a steam tunnel; S3. Nitrogen purging: After the apple pulp chunks have cooled, put them into a closed pulping machine. After starting the equipment, purge nitrogen into the pulping tank. The nitrogen purging parameters are: inlet pressure 0.1-0.4MPa, gas flow rate 10-20L / min. S4. Pulping: While maintaining a continuous flow of nitrogen, start the pulper at a speed of 800 rpm; and add carboxymethyl cellulose and high-fat pectin solution while pulping. S5. Homogenization: Pump the prepared apple puree into a high-pressure homogenizer for homogenization. S6. Degassing: The homogenized apple puree is sent into a vacuum degassing tank for degassing. S7. Sterilization and filling: The apple puree is sterilized and then filled and sealed in a sterile environment.

[0005] Furthermore, the steaming conditions in S2 are: temperature 85-95℃, time 2-4 minutes.

[0006] Furthermore, the pulping time for S4 is 3-8 minutes, the amount of carboxymethyl cellulose is 0.05%-0.10%, and the amount of high-fat pectin is 0.25%-0.35%.

[0007] Furthermore, in S4, the high-fat pectin solution is obtained by mixing high-fat pectin dry powder and maltodextrin dry powder, mixing them evenly, and then dissolving them in hot water; then the high-fat pectin solution is pushed into the pulping machine in a solution state by nitrogen gas.

[0008] Furthermore, in S5, the homogenization pressure is 15-25 MPa.

[0009] Furthermore, in S6, the degassing method is to treat the gas under a vacuum of -0.06 to -0.08 MPa for 5-10 minutes.

[0010] Furthermore, in S7, sterilization employs ultra-high temperature instantaneous sterilization technology, which rapidly heats the apple puree to 110-135°C in a continuous flow system, holds it for 4-30 seconds, and then immediately cools it to below 25°C.

[0011] Furthermore, in S7, the headspace of the packaging is filled with nitrogen before and after filling to replace the residual oxygen inside the packaging.

[0012] Furthermore, it also includes cooling and inspection steps. Cooling is required for hot-filled products, which need to be cooled to room temperature by spraying. Inspection involves sampling and testing for sensory, physicochemical, and microbiological indicators, as well as the integrity of the packaging seal.

[0013] Compared with existing technologies, the apple puree preparation method of the present invention has the following advantages: (1) In the preparation method of apple puree described in this invention, nitrogen gas is introduced during the pulping process. Nitrogen gas can replace ascorbic acid to play an anti-oxidation role. When consumers open the can to eat, the puree can be clearly seen to gradually turn from the white color of fresh fruit to brown color. This process is similar to the gradual oxidation process of fresh fruit cut surface that people usually recognize, allowing consumers to see the additive-free effect of the puree more intuitively.

[0014] (2) In the method for preparing apple puree described in this invention, adding nitrogen during the pulping stage can improve the thickening effect of the chemical thickener. In the case of extending the pulping time, xanthan gum in the thickener can be eliminated. Detailed Implementation

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0016] In this document, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0017] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​falling within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0018] In this article, the terms "multiple" or "more than" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0019] In this document, the terms "preferred" and "more preferred" are used only to describe implementation methods or embodiments with better effects, and should be understood as not constituting a limitation on the scope of protection of this invention.

[0020] In this document, terms such as "further" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0021] In this article, the term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0022] In this document, the term "about" means a specified value of + / - 10%, preferably + / - 5%, and more preferably + / - 1%.

[0023] In this article, the terms “include,” “including,” “have,” “contain,” etc., are all open-ended terms, meaning that they include but are not limited to.

[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention.

[0025] The technical solutions 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] This invention provides a method for preparing apple puree, the method comprising the following steps: S1. Preprocessing: Acceptance and Inspection: Use apple raw materials that meet the standards, and require that pesticide residues, sugar content, acidity and sensory inspections be qualified.

[0027] Washing: Wash the apples with clean water that meets drinking water standards to remove surface dirt, impurities, and some microorganisms.

[0028] Peeling and core removal: Use a mechanical peeler to remove the peel, and then use a corer to remove the core and seed pods to obtain apple pulp chunks.

[0029] S2. Enzyme inactivation by boiling: Apple pulp chunks are heated through a steam tunnel with the following parameters: temperature 85-95℃, time 2-4 minutes.

[0030] S3, Nitrogen filling: After the apple pulp chunks have cooled, they are fed into a closed pulping machine. After starting the equipment, nitrogen gas is introduced into the pulping tank. The nitrogen filling parameters are: inlet pressure 0.1-0.4MPa, gas flow rate 10-20L / min. S4. Pulping: With nitrogen continuously flowing in, start the pulper at 800 rpm for 2-4 minutes to break down and refine the apple pulp.

[0031] Carboxymethyl cellulose (CMC) and high-fat pectin are added during pulping; the amount of carboxymethyl cellulose is 0.05%-0.10%, and the amount of high-fat pectin is 0.25%-0.35%.

[0032] The high-fat pectin is first heated to 90℃-100℃ to completely dissolve the powder, and then pushed into the pulping machine in the solution state by nitrogen gas.

[0033] S5, Homogenization: The prepared apple puree is pumped into a high-pressure homogenizer and homogenized at a pressure of 15-25 MPa. This step aims to further break down the fine particles in the puree, making the thickener network more evenly distributed and obtaining an extremely fine and stable texture.

[0034] S6, Degassing: The homogenized apple puree is then placed in a vacuum degassing tank and treated at a vacuum level of -0.06 to -0.08 MPa for 5-10 minutes. This removes dissolved oxygen from the puree and air bubbles introduced during the pulping and homogenization processes.

[0035] S7. Sterilization: Ultra-high temperature instantaneous sterilization technology is used. The apple puree is rapidly heated to 110-135°C in a continuous flow system, held for 4-30 seconds, and then immediately cooled to below 25°C.

[0036] S8. Aseptic filling and sealing Under aseptic conditions, the cooled apple puree is poured into pre-sterilized packaging containers. The containers are then sealed immediately after filling. Before and after filling, the headspace of the packaging can be purged with nitrogen (headspace purging) to replace any residual oxygen inside the packaging.

[0037] S9, Cooling, Inspection Cooling: For hot-filled products, spray cooling is required to bring them to room temperature.

[0038] Inspection: Sampling is conducted to inspect sensory, physicochemical, and microbiological indicators, as well as the integrity of the packaging seal.

[0039] Example 1: Screening of Nitrogen Purging Parameters To determine whether nitrogen can replace ascorbic acid in its antioxidant effect and to approximate the natural oxidation effect of an apple's everyday cut surface, the following experiment was conducted.

[0040] Experimental conditions: At room temperature of 20℃, use Fuji apples, blend for 3 minutes, and blend at 800 rpm.

[0041] Ascorbic acid, as an antioxidant, is typically added at a concentration of 0.2%-0.5% (by mass).

[0042] Nitrogen addition amount: Nitrogen is not measured in "grams", but is expressed as the volume or pressure of gas filled into the tank. Pressure range: 0.1Mpa-0.4MPa (maintain the tank pressure during processing); continuous gas filling is carried out during pulping, and the nitrogen flow rate is 10-20L / min.

[0043] During the pulping process, six experimental groups and two control groups were set up. The six experimental groups included three ascorbic acid groups and three nitrogen-filled groups. The ascorbic acid groups were supplemented with only 0.2%, 0.3%, and 0.5% ascorbic acid, respectively. The nitrogen-filled groups were supplemented with 0.1 MPa + 10 L / min, 0.2 MPa + 15 L / min, and 0.4 MPa + 20 L / min, respectively. The two control groups were a control group without added apple puree and a control group without added apple cut surfaces. The browning time of each group was observed, and the results are shown in Table 1.

[0044] Table 1 Comparison of data on nitrogen and ascorbic acid

[0045] The experimental results table shows that the oxidation rate of additive-free apple puree is higher than that of naturally cut apples. Even a small amount of ascorbic acid provides a long-lasting antioxidant effect, and the antioxidant time increases with the amount added. The antioxidant effect varies significantly with the amount of nitrogen injected; nitrogen's antioxidant time is significantly shorter than that of ascorbic acid. While the antioxidant time increases with the amount of nitrogen injected, its effectiveness weakens over time. Furthermore, when the nitrogen inlet pressure is 0.1 MPa and the gas flow rate is 10 L / min, the oxidation effect is comparable to that of naturally cut apples. Therefore, based on the above experiments, the optimal nitrogen injection method is determined to be: an inlet pressure of 0.1 MPa and a gas flow rate of 10 L / min, which best approximates the effect of additive-free treatment and has the lowest cost.

[0046] Example 2 Selection of Thickener Thickeners are usually added when preparing fruit puree. In order to reduce the amount of additives, the following is a screening of the selection and dosage of thickeners.

[0047] Experimental conditions: At room temperature of 20℃, using Fuji apples, the pulping time was 3 minutes, the pulping speed was 800 rpm, and the nitrogen charge was 0.1 MPa at 10 L / min.

[0048] The viscosity testing equipment used was a rotational viscometer (NDJ-8S, 25℃, 60r / min). The viscosity value characterizes the flow resistance of the pulp; the higher the value, the greater the consistency.

[0049] The fluid consistency testing equipment uses a Bostwick consistency meter to characterize the fluidity of fruit puree; the smaller the value, the greater the consistency.

[0050] Table 2 Comparison Experiment of Chemical Thickeners

[0051] The table above shows that nitrogen gas alone has a slight thickening effect. Adding CMC, xanthan gum, and nitrogen gas simultaneously results in the highest viscosity. Even with gradually reducing CMC and xanthan gum while maintaining nitrogen gas, a viscosity of over 2000 mPa·s can still be achieved, indicating that reducing the amount of thickener while maintaining nitrogen gas can maintain the thickening effect. Experiments 7 and 8 show that, with the same thickener, extending the beating time improves the thickening effect, and this effect is comparable to that of experiment 6, which adds both types of xanthan gum. Therefore, xanthan gum can be eliminated from the thickener list when extending the beating time.

[0052] Furthermore, experiments numbered 8 and 9 showed that the combination of CMC and nitrogen was more effective than that of xanthan gum and nitrogen.

[0053] Therefore, the preferred solution is: CMC 0.05%, nitrogen 0.1MPa, 10L / min, crushing time 5 minutes, and no xanthan gum needs to be added.

[0054] Example 3: Method of Adding High-Fat Pectin High-fat pectin can be used as a stabilizer to make apple puree stable in structure, with a good taste and easy to swallow.

[0055] Currently, when using high-fat pectin, to achieve better dispersion, the high-fat pectin powder needs to be mixed with 5-10 parts by weight of granulated sugar and pre-dissolved in 85°C hot water to form a high-temperature high-fat pectin solution. Then, after the pulping process, the high-temperature high-fat pectin solution is added to the apple puree for mixing. However, the large size of the granulated sugar particles makes nitrogen blowing difficult, this method is complex, and the high temperature can affect the mixing quality of the fruit puree.

[0056] In this embodiment, the high-fat pectin solution is prepared by mixing high-fat pectin powder with 6 times its weight of maltodextrin powder, mixing well, and then dissolving in hot water.

[0057] The following is a comparative experiment on the state of different high-fat pectin types when high-fat pectin is added during the pulping stage.

[0058] Experimental conditions: At room temperature of 20℃, using Fuji apples, the pulping time was 3 minutes, the pulping speed was 800 rpm, the nitrogen injection rate was 0.1 MPa and 10 L / min, and the amount of high-fat pectin added as a thickener was 0.25% (by weight).

[0059] Table 3 Comparison of states when different high-fat pectins are added

[0060] The experimental data above shows that high-fat pectin, when in powder form, does not disperse well after being blown in with nitrogen. Furthermore, when preparing a high-fat pectin solution, if the pectin is poorly dispersed, the introduction of nitrogen gas does not improve its solubility. Similarly, high-fat pectin solutions dissolved at 90℃-100℃ show browning marks when directly mixed with fruit puree, but no browning marks are observed when nitrogen is introduced into the puree. This is because the high-speed flow of nitrogen gas rapidly lowers the temperature of the high-temperature pectin solution, preventing high-temperature oxidation when added to apple puree at near-100°C.

[0061] Example 4 Preparation of fruit puree A method for preparing apple puree, comprising the following steps: S1. Preprocessing: Acceptance and Inspection: Use apple raw materials that meet the standards, and require that pesticide residues, sugar content, acidity and sensory inspections be qualified.

[0062] Washing: Wash the apples with clean water that meets drinking water standards to remove surface dirt, impurities, and some microorganisms.

[0063] Peeling and core removal: Use a mechanical peeler to remove the peel, and then use a corer to remove the core and seed pods to obtain apple pulp chunks.

[0064] S2. Enzyme inactivation by boiling: Apple pulp chunks are heated through a steam tunnel with the following parameters: temperature 90℃, time 3 minutes.

[0065] S3, Nitrogen filling: After the apple pulp chunks have cooled, they are fed into a closed pulping machine. After starting the equipment, nitrogen gas is introduced into the pulping tank. The nitrogen filling parameters are: inlet pressure 0.1 MPa, gas flow rate 10 L / min. S4. Pulping: With nitrogen continuously flowing in, start the pulper at 800 rpm for 5 minutes to break down and refine the apple pulp.

[0066] Carboxymethyl cellulose (CMC) and high-fat pectin were added during pulping; the amount of carboxymethyl cellulose was 0.05% and the amount of high-fat pectin was 0.25%.

[0067] High-fat pectin powder is mixed with 6 times its weight of maltodextrin powder. After mixing, the mixture is added to water at 90℃-100℃ to completely dissolve the powder. Then, the solution is pushed into a pulping machine by nitrogen gas and stirred.

[0068] S5, Homogenization: The prepared apple puree is pumped into a high-pressure homogenizer and homogenized at a pressure of 20 MPa. This step aims to further break down the fine particles in the puree, making the thickener network more evenly distributed and obtaining an extremely fine and stable texture.

[0069] S6, Degassing: The homogenized apple puree was then placed in a vacuum degassing tank and treated for 5 minutes at a vacuum of -0.08 MPa. This process removed dissolved oxygen and air bubbles introduced during the pulping and homogenization processes.

[0070] S7. Sterilization: Ultra-high temperature instantaneous sterilization technology is used. The apple puree is rapidly heated to 120°C in a continuous flow system, held for 15 seconds, and then immediately cooled to below 25°C.

[0071] S8. Aseptic filling and sealing Under aseptic conditions, the cooled apple puree is poured into pre-sterilized packaging containers. The containers are then sealed immediately after filling. Before and after filling, the headspace of the packaging can be purged with nitrogen (headspace purging) to replace any residual oxygen inside the packaging.

[0072] S9, Cooling, Inspection Cooling: For hot-filled products, spray cooling is required to bring them to room temperature.

[0073] Inspection: Sampling is conducted to inspect sensory, physicochemical, and microbiological indicators, as well as the integrity of the packaging seal.

[0074] The fruit puree prepared by the above method was tested and evaluated, including sensory, physicochemical and microbiological indicators.

[0075] Table 4 Fruit Puree Evaluation

[0076] In summary, the apple puree preparation method described in this invention allows for the introduction of nitrogen gas during the pulping process, which can replace ascorbic acid as an antioxidant and enables the use of a small amount of additives while still meeting the antioxidant requirements. Furthermore, adding nitrogen gas during the pulping stage enhances the thickening effect of chemical thickeners, allowing for the elimination of xanthan gum in the thickener category by extending the pulping time. Adding high-fat pectin during the pulping stage also allows for the use of nitrogen gas to cool the high-temperature high-fat pectin solution (approximately 100°C), eliminating the need to add large amounts of sucrose to improve the solubility of the high-fat pectin, thus allowing it to be added during the pulping stage as well; and completely eliminating the step of pouring the pectin from the pulping tank into the mixing tank.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing apple puree, characterized in that: The method includes the following steps: S1. Pre-treatment: Wash, peel, core and cut the apples into pieces to obtain apple pulp chunks; S2. Steaming to inactivate enzymes: The apple pulp pieces are heated and steamed through a steam tunnel; S3. Nitrogen purging: After the apple pulp chunks have cooled, put them into a closed pulping machine. After starting the equipment, purge nitrogen into the pulping tank. The nitrogen purging parameters are: inlet pressure 0.1-0.4MPa, gas flow rate 10-20L / min. S4. Pulping: While maintaining a continuous flow of nitrogen, start the pulper at a speed of 800 rpm; and add carboxymethyl cellulose and high-fat pectin solution while pulping. S5. Homogenization: Pump the prepared apple puree into a high-pressure homogenizer for homogenization. S6. Degassing: The homogenized apple puree is sent into a vacuum degassing tank for degassing. S7. Sterilization and filling: The apple puree is sterilized and then filled and sealed in a sterile environment.

2. The method for preparing apple puree according to claim 1, characterized in that: The steaming conditions in S2 are: temperature 85-95℃, time 2-4 minutes.

3. The method for preparing apple puree according to claim 1, characterized in that: The pulping time for S4 is 3-8 minutes, the amount of carboxymethyl cellulose is 0.05%-0.10%, and the amount of high-fat pectin is 0.25%-0.35%.

4. The method for preparing apple puree according to claim 1, characterized in that: In S4, the high-fat pectin solution is obtained by mixing high-fat pectin dry powder and maltodextrin dry powder, mixing them evenly, and then dissolving them in hot water; then the high-fat pectin solution is pushed into the pulping machine in a solution state by nitrogen gas.

5. The method for preparing apple puree according to claim 1, characterized in that: In S5, the homogenization pressure is 15-25 MPa.

6. The method for preparing apple puree according to claim 1, characterized in that: In S6, the degassing method is to process the gas under a vacuum of -0.06 to -0.08 MPa for 5-10 minutes.

7. The method for preparing apple puree according to claim 1, characterized in that: In the S7, sterilization uses ultra-high temperature instantaneous sterilization technology, which rapidly heats the apple puree to 110-135℃ in a continuous flow system, holds it for 4-30 seconds, and then immediately cools it to below 25℃.

8. The method for preparing apple puree according to claim 1, characterized in that: In S7, nitrogen is purged into the headspace of the packaging before and after filling to replace residual oxygen inside the packaging.

9. The method for preparing apple puree according to claim 1, characterized in that: It also includes cooling and inspection steps. Cooling is required for hot-filled products, which need to be cooled to room temperature by spraying. Inspection involves sampling and testing for sensory, physicochemical, and microbiological indicators, as well as the integrity of the packaging seal.

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