Preparation process of freeze-dried holboellia latifolia fruit powder with high solubility

Abstract

The invention discloses a preparation technology of freeze-dried holboellia latifolia fruit powder with high solubility in the technical field of food processing. The preparation technology comprises the following steps: S1, selecting holboellia latifolia with moderate maturity; s2, screening and removing bad fruits, then cleaning, sterilizing and air-drying according to the steps, peeling and taking out pulp; s3, manually separating and removing melon seeds in the pulp from the pulp by using a sieve; s4, crushing and grinding the pulp subjected to seed removal in the step S3 to obtain fruit pulp; s5, one of pectinase, protease or cellulase is added into the fruit pulp, the enzymolysis time is 1-6 h, and the enzymolysis pH is 2-4.5; the enzymolysis temperature is 20-70 DEG C; after the enzymolysis is completed, adding a drying aid into the fruit pulp; s6, the fruit pulp obtained in the step S5 is put into a mold to be pre-frozen; and after pre-freezing is completed, putting the fruit pulp and the mold into a vacuum freeze-drying device together, performing freeze-drying treatment under stable vacuum pressure until the fruit pulp is dried into powder, and sealing and storing. According to the scheme, the problem of low solubility of the existing holboellia latifolia powder is solved.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a preparation process of high-solubility freeze-dried wax gourd fruit powder. Background Art

[0002] August melon is a vine plant of the genus Akebia in the family Akebia, also known as August fried, wild banana, etc. It is mainly distributed in Guizhou, Yunnan, and Hunan. Many places in China, such as Hunan, Guizhou, Shaanxi, and Sichuan, have established food safety standards for "August melon". Guizhou Province is a major producer of high-quality August melons, among which the best are the wild resources in the shrubs on the edge of the forest in Tongren City, Guizhou Province. August melon is rich in a variety of nutrients, including carbohydrates, proteins, vitamins, minerals, as well as polyphenols, flavonoids, etc., and contains a variety of amino acids. In recent years, August melon has been established as a new type of fruit, which has been widely planted and developed. It has been developed and applied into fruit wine, fruit oil, fruit tea, etc., and can also play a great role in the fields of medicine and cosmetics.

[0003] Fruit powder is a common deep-processed product of fresh fruits. The main advantages of fruit powder products are: good rehydration, low water activity, no need to add preservatives, and effectively solve the problem that fresh fruits are easy to rot and difficult to sell. At the same time, fruit powder can also be used as a food raw material in beverages, snacks, candies and other foods. However, the solubility of existing August melon and fruit powder is not high, only about 35%, so it is easy to produce particles or lumps when brewing, affecting the taste and smoothness. Summary of the invention

[0004] The present invention aims to provide a preparation process of high-solubility wax gourd freeze-dried fruit powder to solve the problem of low solubility of existing wax gourd powder.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a preparation process of high-solubility freeze-dried wax gourd fruit powder, comprising the following steps:

[0006] S1 Fruit selection: Select wax gourds with moderate maturity;

[0007] S2: cleaning and peeling: screening and removing bad fruits, then cleaning, sterilizing and air-drying according to the steps, peeling and taking out the pulp;

[0008] S3 Seed-to-Pulp Separation: Use a sieve to manually separate the seeds from the pulp;

[0009] S4 beating and homogenizing: crushing and grinding the pulp after the seeds are removed in S3 to obtain wax gourd pulp;

[0010] S5 enzymatic hydrolysis: adding one of pectinase, protease or cellulase to the pulp; the amount of enzyme added is 400-900U / g per 20mL, the enzymatic hydrolysis time is 1-6h, the enzymatic hydrolysis pH is 2-4.5; the enzymatic hydrolysis temperature is 20-70℃; after the enzymatic hydrolysis is completed, a drying agent is added to the pulp, and the amount of the drying agent added is 5-30% of the mass of the pulp;

[0011] S6 vacuum drying: put the fruit pulp with drying aid added in S5 into the mold, put it into the pre-freezing chamber for pre-freezing, the pre-freezing time is 4-6 hours, the temperature is -50℃--45℃; after the pre-freezing is completed, put the pre-frozen fruit pulp together with the mold into the vacuum freeze-drying device, freeze-dry it under stable vacuum pressure until it is dried into powder, and store it in a sealed container.

[0012] Furthermore, the wax gourd with moderate maturity in S1 is characterized by a softened fruit that feels like a ripe persimmon when pinched, and a noticeable white ventral suture, but is not split.

[0013] Furthermore, pectinase is used for enzymatic hydrolysis in S5.

[0014] Furthermore, the drying aid in S5 is one of soluble starch, maltodextrin or β-cyclodextrin.

[0015] Furthermore, the drying aid in S5 is maltodextrin, and the addition amount is 15%.

[0016] Furthermore, the enzymolysis temperature is 30° C. and the enzymolysis pH value is 3.5.

[0017] Beneficial effects of the present invention:

[0018] The solubility of the August melon and fruit powder prepared by this scheme reaches 62.14%, which is about 27% higher than the solubility of the existing August melon and fruit powder of 35%, and the solubility of the August melon and fruit powder is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a single factor result diagram of an embodiment of the preparation process of a high-solubility wax gourd freeze-dried fruit powder of the present invention. DETAILED DESCRIPTION

[0020] The following is further described in detail through specific implementation methods:

[0021] Example 1

[0022] A preparation process of high-solubility freeze-dried wax gourd fruit powder comprises the following steps:

[0023] S1 Fruit selection: Select wax gourds that are moderately mature. The fruit should be soft and feel like a ripe persimmon when picked up. The ventral suture should be obviously white but not split.

[0024] S2: cleaning and peeling: screening and removing bad fruits, then cleaning, sterilizing and air-drying according to the steps, peeling and taking out the pulp;

[0025] S3 Seed-to-Pulp Separation: Use a sieve to manually separate the seeds from the pulp;

[0026] S4 beating and homogenizing: crushing and grinding the pulp after the seeds are removed in S3 to obtain wax gourd pulp;

[0027] S5 enzymatic hydrolysis: add cellulase to the pulp; the amount of enzyme added is 400U / g per 20mL, the enzymatic hydrolysis time is 1h, the enzymatic hydrolysis pH is 2, the enzymatic hydrolysis temperature is 20℃; after the enzymatic hydrolysis is completed, add soluble starch to the pulp, the amount of soluble starch added is 5% of the mass of the pulp,

[0028] S6 vacuum drying: put the fruit pulp with soluble starch added in S5 into a mold and put it into a pre-freezing chamber for pre-freezing. The pre-freezing time is 4 hours and the temperature is -50°C. After the pre-freezing is completed, put the pre-frozen fruit pulp together with the mold into a vacuum freeze-drying device and perform freeze-drying treatment under stable vacuum pressure until it is dried into powder and then sealed for storage.

[0029] Example 2

[0030] A preparation process of high-solubility freeze-dried wax gourd fruit powder comprises the following steps:

[0031] S1 Fruit selection: Select wax gourds that are moderately mature. The fruit should be soft and feel like a ripe persimmon when picked up. The ventral suture should be obviously white but not split.

[0032] S2: cleaning and peeling: screening and removing bad fruits, then cleaning, sterilizing and air-drying according to the steps, peeling and taking out the pulp;

[0033] S3 Seed-to-Pulp Separation: Use a sieve to manually separate the seeds from the pulp;

[0034] S4 beating and homogenizing: crushing and grinding the pulp after the seeds are removed in S3 to obtain wax gourd pulp;

[0035] S5 enzymatic hydrolysis: pectinase was added to the pulp; the amount of enzyme added was 500U / g per 20mL, the enzymatic hydrolysis time was 2h, the enzymatic hydrolysis pH was 3.5, and the enzymatic hydrolysis temperature was 30°C; after the enzymatic hydrolysis was completed, maltodextrin was added to the pulp, and the amount of maltodextrin added was 15% of the mass of the pulp,

[0036] S6 vacuum drying: put the fruit pulp with maltodextrin added in S5 into a mold and put it into a pre-freezing chamber for pre-freezing. The pre-freezing time is 5 hours and the temperature is -48°C. After the pre-freezing is completed, put the pre-frozen fruit pulp together with the mold into a vacuum freeze-drying device and perform freeze-drying treatment under stable vacuum pressure until it is dried into powder and then sealed for storage.

[0037] Example 3

[0038] A preparation process of high-solubility freeze-dried wax gourd fruit powder comprises the following steps:

[0039] S1 Fruit selection: Select wax gourds that are moderately mature. The fruit should be soft and feel like a ripe persimmon when picked up. The ventral suture should be obviously white but not split.

[0040] S2: cleaning and peeling: screening and removing bad fruits, then cleaning, sterilizing and air-drying according to the steps, peeling and taking out the pulp;

[0041] S3 Seed-to-Pulp Separation: Use a sieve to manually separate the seeds from the pulp;

[0042] S4 beating and homogenizing: crushing and grinding the pulp after the seeds are removed in S3 to obtain wax gourd pulp;

[0043] S5 enzymatic hydrolysis: add one of pectinase, protease or cellulase to the pulp; the enzyme addition amount is 900U / g per 20mL, the enzymatic hydrolysis time is 6h, the enzymatic hydrolysis pH is 4.5, the enzymatic hydrolysis temperature is 70℃; after the enzymatic hydrolysis is completed, add β-cyclodextrin to the pulp, the addition amount of β-cyclodextrin is 30% of the mass of the pulp,

[0044] S6 vacuum drying: put the fruit pulp with β-cyclodextrin added in S5 into a mold and put it into a pre-freezing chamber for pre-freezing. The pre-freezing time is 4-6 hours and the temperature is -50℃--45℃. After the pre-freezing is completed, put the pre-frozen fruit pulp together with the mold into a vacuum freeze-drying device and perform freeze-drying treatment under stable vacuum pressure until it is dried into powder and sealed for storage.

[0045] Single factor experiment

[0046] Under fixed process parameters, 1.00 g of August melon fruit powder was weighed and the solid-liquid ratio was 1:20 g / mL. The effects of pectinase addition amount (400, 500, 600, 700, 900 U / g), enzymolysis time (1, 2, 3, 4, 5, 6 h), enzymolysis pH (2, 2.5, 3, 3.5, 4, 4.5) and enzymolysis temperature (20, 30, 40, 50, 60, 70 ℃) on the dissolution of August melon fruit powder were investigated.

[0047] Under fixed process parameters, 1.00 g of wax gourd fruit powder was weighed, with a solid-liquid ratio of 1:20 g / mL, and the effect of the addition amount of maltodextrin (5%, 10%, 15%, 20%, 25%, 30%) on the dissolution of wax gourd freeze-dried fruit powder was investigated.

[0048] Orthogonal Experimental Design

[0049] On the basis of single factor experiment, taking significant single factor as experimental factor and solubility of August melon fruit powder as evaluation index, orthogonal test analysis was carried out to optimize the production process conditions of August melon fruit powder.

[0050] Solubility determination

[0051] Weigh 1.00g of August melon fruit powder in a 50mL beaker, add 10mL of distilled water, mix well, take 1mL of solution, centrifuge at 1500r / min for 3min, collect the supernatant in a plate, freeze-dry and weigh, calculate the solubility. Calculation formula: Solubility (%) = (total mass of solid residue and culture dish after freeze-drying - mass of culture dish) × volume of distilled water added / mass of fruit powder × 100%.

[0052] Determination of caking degree

[0053] The vacuum freeze-dried and crushed fruit powder was weighed, passed through a 40-mesh sieve, and the residual mass on the sieve was recorded. The agglomeration degree was calculated by the ratio of the mass of the fruit powder remaining on the sieve to the mass of the original sample.

[0054] Oil retention determination

[0055] According to the method of Shi Li et al., with slight modifications, 0.10 g of August melon fruit powder sample was accurately weighed, 5 mL of vegetable oil was added, shaken, placed in a refrigerator at 4°C, and allowed to stand for 24 hours. Centrifuged at 4500 r / min for 15 minutes in a centrifuge, the supernatant was removed, and the residual liquid was absorbed with oil-absorbing paper, and the wet weight of the sample was weighed.

[0056] Oil retention (g / g) = (m-m0) / m0

[0057] Where: wet weight of oil-saturated sample m, g; dry weight of sample m0, g.

[0058] Water holding capacity determination

[0059] Take 0.50g of August melon fruit powder in a 50mL centrifuge tube, add 20mL of distilled water, stir magnetically for 30min, and then centrifuge at 4500r·min-1 for 15min at room temperature. After removing the supernatant, weigh the precipitate.

[0060] Oil retention (g / g) = (m-m0) / m0

[0061] Where: m: wet weight of the sample after saturation with water, g; m0: dry weight of the sample, g.

[0062] Depend on Figure 1 As shown in Figure A, with the increase of enzyme addition, the solubility of August melon powder shows a trend of first increasing and then stabilizing. When the enzyme addition reaches 500U / g, the solubility reaches the highest point, which is 53.66%. This may be because when it is lower than 500U / g, the pectinase fails to fully enzymolyze the pectin in the pulp, resulting in the pectin in the pectin tissue not being fully broken and exposed. When the enzyme addition is greater than 500U / g, the pectinase fully enzymolyzes, keeping the reaction in a hydrolysis equilibrium state, and the solubility no longer changes. In summary, a pectinase concentration of 500U / g was selected for subsequent experiments.

[0063] Figure 1 As shown in Figure B, maltodextrin is beneficial for removing moisture during vacuum freeze drying, and maltodextrin can form a film on the surface of fruit powder, which can reduce the problems of fruit powder agglomeration and wall sticking during drying and improve the yield of the product. With the increase of maltodextrin addition, the solubility of August melon fruit powder gradually increases. It may be that the water molecules embedded in maltodextrin have to penetrate the maltodextrin with a larger molecular weight and sublimate during the drying process. When the amount of maltodextrin added is increased to 15%, the solubility reaches the highest point. If the amount of maltodextrin added is further increased, the performance of the fruit powder will decrease. In summary, this experiment selects a maltodextrin dosage of 10% to 20% for subsequent orthogonal experiments.

[0064] Figure 1 As shown in Figure C, before 2 hours, as the enzymatic hydrolysis time increased, the solubility of August melon and fruit powder gradually increased until the solubility reached the highest point of 54.50% at 2 hours; then, even if the enzymatic hydrolysis time continued to be extended, the solubility remained unchanged. The essence of enzyme catalysis is the combination of enzyme and substrate, thereby reducing the activation energy of the reactants and increasing the solubility. Therefore, the enzymatic hydrolysis time is not a significant factor affecting the experiment. In summary, 2 hours was selected for subsequent experiments.

[0065] Figure 1 As shown in Figure D, the solubility of August melon and fruit powder is significantly affected by the enzymatic hydrolysis temperature. As the temperature rises, the solubility gradually increases. Specifically, when the temperature rises to 40°C, the solubility reaches its highest point, which is 54.34%. However, as the temperature continues to rise, the solubility decreases rapidly. The main influencing factor is the activity of the enzyme. Appropriately increasing the temperature can enhance the enzyme activity, promote the reaction, and accelerate the molecular thermal motion; but too high a temperature will inactivate the enzyme, thereby inhibiting the enzymatic hydrolysis reaction and reducing the efficiency

[28] . In summary, 30-50°C was selected for the subsequent orthogonal experiment.

[0066] Figure 1As shown in Figure E, the solubility of August melon fruit powder is significantly affected by the pH of the enzymatic hydrolysis. As the pH of the enzymatic hydrolysis increases, the solubility gradually increases. Specifically, when the pH reaches 3.5, the solubility reaches its highest point, which is 54.73%; then, as the pH further increases, the solubility decreases rapidly and tends to stabilize. The main influencing factor is the activity of the enzyme. The pH suitable for the pectinase reaction can enhance the enzyme activity, promote the reaction, and accelerate the molecular thermal motion; but when the pH exceeds the appropriate pH, the efficiency will decrease

[29] . In summary, the enzymatic hydrolysis pH value of 3 to 4 was selected for subsequent orthogonal experiments.

[0067] Analysis of orthogonal test results

[0068] Taking maltodextrin addition (A), enzymatic hydrolysis temperature (B), and enzymatic hydrolysis pH (C) as experimental factors and August melon fruit powder solubility as evaluation index, L9 (33) three-factor three-level orthogonal test analysis was carried out to optimize the production process conditions of August melon fruit powder. The values ​​of each factor level are shown in Table 1 Orthogonal test design table

[0069]

[0070] Table 1 Orthogonal experimental design table

[0071]

[0072] Table 2 Orthogonal test results

[0073] As shown in Table 2, the order of influence of various factors on the solubility of August melon and fruit powder is: A>C>B, that is, maltodextrin addition>enzyme hydrolysis pH>enzyme hydrolysis temperature. The best combination is A2B1C2, that is, maltodextrin addition of 15%, enzyme hydrolysis temperature of 30℃, and enzyme hydrolysis pH of 3.5.

[0074] To verify the results of the orthogonal test, three parallel tests were conducted according to the process flow. The average solubility of the fruit powder was measured to be 60.87%. The results proved that the process obtained by the orthogonal test is feasible.

[0075] Product physical characteristics test results

[0076]

[0077] Table 3 Product physical characteristics results

[0078] As shown in Table 3, the physical and chemical properties of the fruit powder after treatment will be different. The solubility of the fruit powder after the process optimization in this study reached 62.14%, which was 27.56% higher than the solubility of the original fruit powder of 34.58%. This shows that the solubility of August melon fruit powder can be significantly improved after the process optimization.

Claims

1. A preparation process of high-solubility freeze-dried wax gourd fruit powder, characterized in that: The following steps are involved: S1 Fruit selection: Select wax gourds with moderate maturity; S2: cleaning and peeling: screening and removing bad fruits, then cleaning, sterilizing and air-drying according to the steps, peeling and taking out the pulp; S3 Seed-to-Pulp Separation: Use a sieve to manually separate the seeds from the pulp; S4 beating and homogenizing: crushing and grinding the pulp after the seeds are removed in S3 to obtain wax gourd pulp; S5 enzymatic hydrolysis: adding one of pectinase, protease or cellulase to the pulp; the amount of enzyme added is 400-900U / g per 20mL, the enzymatic hydrolysis time is 1-6h, the enzymatic hydrolysis pH is 2-4.5; the enzymatic hydrolysis temperature is 20-70℃; after the enzymatic hydrolysis is completed, a drying agent is added to the pulp, and the amount of the drying agent added is 5-30% of the mass of the pulp; S6 vacuum drying: put the fruit pulp with drying aid added in S5 into the mold, put it into the pre-freezing chamber for pre-freezing, the pre-freezing time is 4-6 hours, the temperature is -50℃--45℃; after the pre-freezing is completed, put the pre-frozen fruit pulp together with the mold into the vacuum freeze-drying device, freeze-dry it under stable vacuum pressure until it is dried into powder, and store it in a sealed container.

2. The preparation process of the high-solubility freeze-dried wax gourd fruit powder according to claim 1, characterized in that: The wax gourd with moderate maturity in S1 is characterized by a softened fruit that feels like a ripe persimmon when pinched, and a noticeable white ventral suture, but is not split.

3. The preparation process of the high-solubility freeze-dried wax gourd fruit powder according to claim 2, characterized in that: Pectinase was used for enzymatic hydrolysis in S5.

4. The preparation process of the high-solubility freeze-dried wax gourd fruit powder according to claim 3, characterized in that: The drying aid in S5 is one of soluble starch, maltodextrin or β-cyclodextrin.

5. The process for preparing the high-solubility freeze-dried wax gourd fruit powder according to claim 4, characterized in that: The drying aid in S5 is maltodextrin, and the addition amount is 15%.

6. The process for preparing the high-solubility freeze-dried wax gourd fruit powder according to claim 5, characterized in that: The enzymolysis temperature is 30° C., and the enzymolysis pH value is 3.5.

Images