Preparation method of antioxidant fruit juice

Abstract

The invention belongs to the technical field of food, and discloses a preparation method of antioxidant fruit juice. The preparation method of the fruit juice comprises the following steps: (1) taking pulp, pulping, adding a first compound enzyme, and carrying out first enzymolysis treatment to obtain a product; (2) freezing a product obtained in the step (1), then heating, adding a second compound enzyme, carrying out secondary enzymolysis treatment, colloid milling, filtering and sterilizing to obtain antioxidant fruit juice; the first compound enzyme comprises pectinase and endoglucanase; the temperature of the first enzymolysis treatment is 40-55 DEG C, and the treatment time is 20-30 minutes; the second compound enzyme comprises pectinase and glucose oxidase; the temperature of the second enzymolysis treatment is 40-45 DEG C, and the treatment time is 40-60 minutes. The fruit juice is good in anti-oxidation stability, not prone to browning and high in vitamin C content and carotenoid content.

Description

Technical Field

[0001] The invention belongs to the technical field of food, and particularly relates to a method for preparing antioxidant juice. Background Art

[0002] Different fruits have different nutritional content, which also makes the market prices of different fruits vary greatly. The skin and flesh of yellow peach are golden yellow to orange yellow, and the flesh is dense and tough. Yellow peach is very nutritious, containing rich vitamin C and a large amount of dietary fiber, carotene, lycopene, lycopene and trace elements (iron, calcium, etc.), and has both fresh eating and processable characteristics. Yellow peach has the functions of invigorating qi and blood and producing body fluids, so it is very popular in the domestic and foreign markets. Yellow peach has a thin skin, soft and juicy flesh, high water content, and the ripening period is mostly concentrated in July and August. It matures quickly after picking and is very easy to rot. Processing yellow peaches into fruit juice beverages is not only conducive to solving the problems of production, sales, transportation and storage during the fruit harvest season, but also can generate greater economic benefits.

[0003] However, during the production and processing of yellow peach juice beverages, browning problems are prone to occur due to the presence of polyphenol oxidase, oxygen, polyphenols and vitamin C. Browning not only affects the sensory perception of juice products, but also causes the loss of nutrients, while affecting the shelf life of products and reducing product stability. At present, the beverage industry generally adopts the method of adding more antioxidants to inhibit oxidation, but excessive use of oxidants may have adverse effects on human health.

[0004] Therefore, there is an urgent need to provide a safe antioxidant technology for producing yellow peach juice. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides a method for preparing an antioxidant juice. The juice preparation method of the present invention does not involve the addition of antioxidants, and also enables the juice to effectively release and stabilize antioxidant components during the processing process, thereby improving the antioxidant stability of the juice and maintaining rich application components. For example, the juice is not prone to browning, and has high content of vitamin C and carotenoids.

[0006] The present invention provides a method for preparing an antioxidant juice, comprising the following steps:

[0007] (1) taking pulp, beating it, adding a first complex enzyme, performing a first enzymatic hydrolysis treatment, and obtaining a product;

[0008] (2) freezing the product of step (1), then heating it, adding a second complex enzyme, performing a second enzymatic hydrolysis treatment, grinding, filtering, and sterilizing to obtain the antioxidant juice;

[0009] The first complex enzyme includes pectinase and endoglucanase;

[0010] The temperature of the first enzymatic hydrolysis treatment is 40-55°C, and the treatment time is 20-30 minutes;

[0011] The second complex enzyme includes pectinase and glucose oxidase;

[0012] The temperature of the second enzymatic hydrolysis treatment is 40-45°C, and the treatment time is 40-60 minutes.

[0013] Preferably, in step (1), the pulp is yellow peach pulp.

[0014] Preferably, in step (1), the mass of the first complex enzyme is 0.010-0.030% of the mass of the pulp, and more preferably 0.015-0.020%.

[0015] Preferably, in step (1), in the first complex enzyme, the mass ratio of pectinase to endoglucanase is 1:(0.3-0.8), and more preferably 1:(0.5-0.7).

[0016] Preferably, in step (1), the freezing temperature is -4°C to 4°C, more preferably 0-1°C.

[0017] Preferably, in step (1), the freezing time is 1-8 hours, more preferably 2-5 hours.

[0018] Preferably, in step (1), before pulping, the pulp is first soaked in a mixed solution of sodium D-isoascorbate and citric acid with a mass fraction of 0.04-0.1% for 30-50 minutes, and then the pulp is taken out and washed with water.

[0019] Preferably, in the mixed solution of sodium D-isoascorbate and citric acid, the mass ratio of sodium D-isoascorbate to citric acid is 1:(1-2), and more preferably 1:(1-1.5). Soaking in the mixed solution of sodium D-isoascorbate and citric acid helps to enhance the antioxidant effect of the juice.

[0020] Preferably, malic acid is also added to the mixed solution of sodium D-isoascorbate and citric acid. Preferably, the mass ratio of malic acid to citric acid is 1:(0.5-2), more preferably 1:(1-1.5). Further addition of malic acid helps to further increase the content of vitamin C and carotenoids in the juice.

[0021] Preferably, in step (1), the temperature of the first enzymatic hydrolysis treatment is 48-50°C, and the treatment time is 25-30 minutes.

[0022] Preferably, in step (2), the temperature of the second enzymatic hydrolysis treatment is 43-45° C., and the treatment time is 50-60 minutes.

[0023] Preferably, in step (2), the mass of the second complex enzyme is 0.015-0.040% of the mass of the pulp, and more preferably 0.020-0.025%.

[0024] Preferably, in step (2), in the second complex enzyme, the mass ratio of pectinase to glucose oxidase is 1:(0.3-0.8), and more preferably 1:(0.5-0.7).

[0025] Preferably, in step (2), the filtration screen has a mesh size of 100-200.

[0026] Preferably, in step (2), the sterilization is carried out at 95-100°C.

[0027] Preferably, in step (2), after filtering, sodium carboxymethyl cellulose is added, sheared for 5-10 minutes, and fructose syrup, acidulant and sweetener are added.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] The juice preparation method of the present invention performs enzymatic hydrolysis twice, and through specific composite enzymes and enzymatic hydrolysis conditions, the final juice has good antioxidant properties, high vitamin and carotenoid content, and the juice is not easy to brown and has good stability. The specific enzymatic hydrolysis conditions are that the first composite enzyme includes pectinase and endoglucanase; the temperature of the first enzymatic hydrolysis treatment is 40-55°C, and the treatment time is 20-30 minutes; after the first enzymatic hydrolysis treatment of pectinase and endoglucanase, the temperature is cooled and frozen to ensure the stability of antioxidant nutrients, and then the second enzymatic hydrolysis treatment is performed, and the second composite enzyme includes pectinase and glucose oxidase; the temperature of the second enzymatic hydrolysis treatment is 40-45°C, and the treatment time is 40-60 minutes, which further fully releases the nutrients in the pulp and maintains its stability. Thereby maintaining the flavor and color of the juice and extending the shelf life of the product. DETAILED DESCRIPTION

[0030] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0031] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0032] 1. Pretreatment of yellow peach pulp:

[0033] Screening of yellow peach pulp: 100 g of yellow peach pulp of different maturity from various manufacturers were selected, thawed at room temperature, pulped, and the sensory flavor was evaluated.

[0034] Table 1: Flavors of yellow peach pulp varieties

[0035]

[0036]

[0037] As can be seen from Table 1, the flesh of the 80% ripe yellow peach provided by Gelipu is golden in color, moderately soft and hard, relatively sweet, and has a strong aroma, which meets the production and processing requirements.

[0038] 2. Selection of thawing methods for yellow peach pulp: Take one piece (10kg) of yellow peach pulp and thaw it using different thawing methods. Compare and analyze the differences in yellow peach pulp color, juice loss rate, vitamin C content, soluble solid content and other indicators under five thawing methods: low-temperature air thawing (ambient temperature 4℃), normal temperature air thawing (room temperature 25℃), running water thawing (water temperature 24℃), warm water thawing (water temperature 50℃) and microwave thawing (thawing mode), and select the appropriate thawing method.

[0039] Table 2: Selection of thawing methods for yellow peach pulp

[0040]

[0041] As can be seen from Table 1, running water thawing has the advantages of short thawing time, low juice loss rate, low vitamin loss rate, etc. It is beneficial to maintain the quality of yellow peach pulp and is the best thawing method.

[0042] The yellow peach pulp used in the following examples and comparative examples is 80% ripe yellow peach pulp provided by Gelipu, and is thawed by running water thawing.

[0043] Example 1

[0044] A method for preparing an antioxidant juice comprises the following steps:

[0045] (1) taking 1 kg of yellow peach pulp, beating it, adding a first complex enzyme, and performing a first enzymatic hydrolysis treatment to obtain a product;

[0046] (2) freezing the product of step (1) at 0° C. for 2 hours, then heating to 45° C., adding a second complex enzyme, performing a second enzymatic hydrolysis treatment, grinding in a colloid mill for 2 minutes, filtering through a 100-mesh filter, and sterilizing at 95° C. for 20 minutes to obtain an antioxidant juice;

[0047] The first complex enzyme includes pectinase and endoglucanase, and the mass ratio of pectinase to endoglucanase is 1:0.5;

[0048] The temperature of the first enzymatic hydrolysis treatment was 50°C and the treatment time was 25 minutes;

[0049] The mass of the first complex enzyme is 0.020% of the mass of yellow peach pulp;

[0050] The second complex enzyme includes pectinase and glucose oxidase, and the mass ratio of pectinase to glucose oxidase is 1:0.5;

[0051] The temperature of the second enzymatic hydrolysis treatment was 45°C and the treatment time was 50 minutes;

[0052] The mass of the second complex enzyme is 0.025% of the mass of the pulp.

[0053] Example 2

[0054] A method for preparing an antioxidant juice comprises the following steps:

[0055] (1) taking 1 kg of yellow peach pulp, soaking the yellow peach pulp in a mixed solution of sodium D-isoascorbate and citric acid with a mass fraction of 0.05% for 50 minutes, then taking out the yellow peach pulp, washing it with water for 5 times, mixing it with a mixed solution of sodium D-isoascorbate and citric acid, wherein the mass ratio of sodium D-isoascorbate to citric acid is 1:1, then beating the pulp, adding a first complex enzyme, and performing a first enzymatic hydrolysis treatment to obtain a product;

[0056] (2) freezing the product of step (1) at 0° C. for 2 hours, then heating to 45° C., adding a second complex enzyme, performing a second enzymatic hydrolysis treatment, grinding in a colloid mill for 2 minutes, filtering through a 100-mesh filter, and sterilizing at 95° C. for 20 minutes to obtain an antioxidant juice;

[0057] The first complex enzyme includes pectinase and endoglucanase, and the mass ratio of pectinase to endoglucanase is 1:0.5;

[0058] The temperature of the first enzymatic hydrolysis treatment was 50°C and the treatment time was 25 minutes;

[0059] The mass of the first complex enzyme is 0.020% of the mass of yellow peach pulp;

[0060] The second complex enzyme includes pectinase and glucose oxidase, and the mass ratio of pectinase to glucose oxidase is 1:0.5;

[0061] The temperature of the second enzymatic hydrolysis treatment was 45°C and the treatment time was 50 minutes;

[0062] The mass of the second complex enzyme is 0.025% of the mass of the pulp.

[0063] Example 3

[0064] A method for preparing an antioxidant juice comprises the following steps:

[0065] (1) taking 1 kg of yellow peach pulp, soaking the yellow peach pulp in a mixed solution of sodium D-isoascorbate, citric acid and malic acid with a mass fraction of 0.05% for 50 minutes, then taking out the yellow peach pulp, washing it with water for 5 times, mixing the mixed solution of sodium D-isoascorbate and citric acid, wherein the mass ratio of sodium D-isoascorbate to citric acid and malic acid is 1:1:1, then beating the pulp, adding a first complex enzyme, performing a first enzymatic hydrolysis treatment, and obtaining a product;

[0066] (2) freezing the product of step (1) at 0° C. for 2 hours, then heating to 45° C., adding a second complex enzyme, performing a second enzymatic hydrolysis treatment, grinding in a colloid mill for 2 minutes, filtering through a 100-mesh filter, and sterilizing at 95° C. for 20 minutes to obtain an antioxidant juice;

[0067] The first complex enzyme includes pectinase and endoglucanase, and the mass ratio of pectinase to endoglucanase is 1:0.5;

[0068] The temperature of the first enzymatic hydrolysis treatment was 50°C and the treatment time was 25 minutes;

[0069] The mass of the first complex enzyme is 0.020% of the mass of yellow peach pulp;

[0070] The second complex enzyme includes pectinase and glucose oxidase, and the mass ratio of pectinase to glucose oxidase is 1:0.5;

[0071] The temperature of the second enzymatic hydrolysis treatment was 45°C and the treatment time was 50 minutes;

[0072] The mass of the second complex enzyme is 0.025% of the mass of the pulp.

[0073] Comparative Example 1

[0074] Compared with Example 1, the difference of Comparative Example 1 is that an equal amount of glucose oxidase is used to replace endoglucanase, and the rest of the process is the same as Example 1.

[0075] Comparative Example 2

[0076] Compared with Example 1, the difference of Comparative Example 2 is that the freezing process is replaced by placing the mixture at room temperature for 2 hours, and the rest of the process is the same as that of Example 1.

[0077] Comparative Example 3

[0078] Compared with Example 1, the difference of Comparative Example 3 is that the first enzymatic hydrolysis and freezing are not performed, and the rest of the process is the same as that of Example 1. That is, Comparative Example 3 performs one enzymatic hydrolysis.

[0079] Comparative Example 4

[0080] Compared with Example 1, the difference of Comparative Example 4 is that the temperature of the first enzymatic hydrolysis treatment is 38°C and the treatment time is 25 minutes; the temperature of the second enzymatic hydrolysis treatment is 50°C and the treatment time is 50 minutes, and the rest of the process is the same as Example 1.

[0081] Product effect testing

[0082] The juices prepared in the above examples and comparative examples were tested for vitamin C and carotenoid content in the juices according to conventional methods. The results are shown in Table 3.

[0083] Table 3

[0084]

[0085] It can be seen from Table 3 that the vitamin C and carotenoid contents in the juice prepared in the examples of the present invention are significantly higher than those in comparative examples 1 to 4. It can also be seen that the two enzymatic hydrolysis treatments and the freezing process in the juice preparation method of the present invention have a significant effect on the vitamin C and carotenoid contents of the juice.

Claims

1. A method for preparing an antioxidant juice, characterized in that: The following steps are involved: (1) taking pulp, beating it, adding a first complex enzyme, performing a first enzymatic hydrolysis treatment, and obtaining a product; (2) freezing the product of step (1), then heating it, adding a second complex enzyme, performing a second enzymatic hydrolysis treatment, grinding, filtering, and sterilizing to obtain the antioxidant juice; The first complex enzyme includes pectinase and endoglucanase; The temperature of the first enzymatic hydrolysis treatment is 40-55°C, and the treatment time is 20-30 minutes; The second complex enzyme includes pectinase and glucose oxidase; The temperature of the second enzymatic hydrolysis treatment is 40-45°C, and the treatment time is 40-60 minutes.

2. The method for preparing juice according to claim 1, characterized in that: In step (1), the fruit pulp is yellow peach pulp; and / or the mass of the first complex enzyme is 0.010-0.030% of the mass of the fruit pulp.

3. The method for preparing juice according to claim 1, characterized in that: In step (1), in the first complex enzyme, the mass ratio of pectinase to endoglucanase is 1:(0.3-0.8).

4. The method for preparing juice according to claim 1, characterized in that: In step (1), the freezing temperature is between -4°C and 4°C.

5. The method for preparing juice according to claim 4, characterized in that: In step (1), the freezing time is 1-8 hours.

6. The method for preparing juice according to any one of claims 1 to 5, characterized in that: In step (1), before pulping, the pulp is first soaked in a mixed solution of sodium D-isoascorbate and citric acid with a mass fraction of 0.04-0.1% for 30-50 minutes, and then the pulp is taken out and washed with water.

7. The method for preparing juice according to claim 6, characterized in that: In the mixed solution of sodium D-isoascorbate and citric acid, the mass ratio of sodium D-isoascorbate to citric acid is 1:(1-2).

8. The method for preparing juice according to claim 6, characterized in that: Malic acid is also added to the mixed solution of sodium D-isoascorbate and citric acid.

9. The method for preparing juice according to claim 1, characterized in that: The mass of the second complex enzyme is 0.015-0.040% of the mass of the pulp.

10. The method for preparing juice according to claim 1, characterized in that: In step (2), in the second complex enzyme, the mass ratio of pectinase to glucose oxidase is 1:(0.3-0.8); and / or, in step (2), the sterilization is carried out at 95-100°C.

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