Combination method for improving taste of cerasus humilis clear juice and increasing content of available calcium and zinc

Abstract

The invention belongs to the technical field of biology, and relates to a combined method for improving the taste of cerasus humilis clear juice and increasing the content of available calcium and zinc, which comprises the following operation steps: S1, removing impurities from cerasus humilis fruits, cleaning, denucleating and crushing to obtain cerasus humilis pulp; s2, performing primary enzymolysis on the cerasus humilis fruit pulp to obtain primary enzymolysis cerasus humilis fruit pulp; s3, fermenting the cerasus humilis fruit pulp to obtain fermented cerasus humilis fruit pulp; s4, performing secondary enzymolysis on the fermented cerasus humilis fruit pulp to obtain secondary enzymolysis cerasus humilis fruit pulp; and S5, filtering, sterilizing and filling the secondary enzymolysis cerasus humilis pulp to obtain a cerasus humilis clear juice product. The combined method of high-speed dispersion machine release, pectinase enzymolysis, issatchenkia terricola fermentation and joint enzymolysis of cellulase, beta-glucosidase and alpha-rhamnosidase is utilized, the product taste is effectively improved while the yield of the cerasus humilis clear juice product is increased, and the cerasus humilis clear juice product is palatable in sourness and sweetness, clear, transparent and bright, full in flavor and suitable for large-scale production. And the contents of calcium and zinc are increased by more than 65% and 59%. The product has good calcium and zinc supplementing effects.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and particularly relates to a combined method for improving the taste of lychee juice and increasing the contents of available calcium and zinc. Background Art

[0002] The European plum (Cerasus humilis) belongs to the genus Ceraras in the Rosaceae family. Its bushes are cold- and drought-tolerant, and its ability to retain soil and water, as well as prevent wind and sand, makes it well-suited to the cold climates of Northeast China and the arid climates of the central and western regions. Its fruit is brightly colored and its flesh is delicious. Rich in naturally active calcium, zinc, and iron, it is also known as the calcium fruit due to its high calcium content. The fruit is also rich in active substances such as polyphenols, flavonoids, vitamins, organic acids, unsaturated fatty acids, and other essential trace elements.

[0003] The active calcium in lychee can be directly absorbed and utilized by the human body. However, due to differences in processing techniques, the active calcium and zinc in lychee juice are significantly lost compared to the whole fruit, resulting in inadequate utilization. Calcium plays a vital role in the growth and development of bones, nerves, and muscles. In addition to directly influencing height, it also has other important physiological functions within the body. These functions are crucial for maintaining overall health and ensuring normal growth and development. Calcium also regulates heart rate, reduces cardiovascular permeability, controls inflammation and edema, and maintains acid-base balance. Zinc is an essential trace element for the human body, playing a crucial role in key physiological processes such as growth and development, reproduction and inheritance, immunity, and endocrine function. It has been dubbed the "flower of life," "source of intelligence," and "factor of marital harmony."

[0004] Prunus tiliaceus fruit is commonly processed into beverages, fruit milks, canned foods, and other foods, but clear tiliaceus fruit juice is extremely rare on the market. The high organic acid content in Prunus tiliaceus fruit results in a pronounced sour taste, which can also be a sharp sour sensation in juice, making it difficult for consumers to accept. Developing clear juice products with a pleasant taste and high calcium and zinc content would benefit the Prunus tiliaceus processing industry and provide consumers with a product that supplements calcium, zinc, and other minerals, promising promising market opportunities. Summary of the Invention

[0005] The object of the present invention is to provide a combined method for improving the taste of lychee juice and increasing the available calcium and zinc contents. After treatment by the combined method, the water-soluble and acid-soluble calcium and zinc contents in the lychee juice are increased by more than 65% and 59%, respectively. The obtained lychee juice has an appropriate sweet and sour taste, is refreshing and has a prominent lychee flavor, and is suitable for all ages.

[0006] The present invention is achieved through the following technical solutions.

[0007] A combined method for improving the taste of European prunes juice and increasing the available calcium and zinc contents, the operating steps comprising: S1: removing impurities, washing, removing cores, and crushing European prunes fruits to obtain European prunes pulp; S2: performing a first enzymatic hydrolysis on the European prunes pulp to obtain a primary enzymatic hydrolyzed European prunes pulp; S3: fermenting the European prunes pulp to obtain a fermented European prunes pulp; S4: performing a second enzymatic hydrolysis on the fermented European prunes pulp to obtain a secondary enzymatic hydrolyzed European prunes pulp; and S5: filtering, sterilizing, and filling the secondary enzymatic hydrolyzed European prunes pulp to obtain the European prunes juice product.

[0008] Among them, in S1, a high-speed disperser is used to crush the fruit pulp, pectinase is used for the first enzymatic hydrolysis, and cellulase, β-glucosidase and α-rhamnosidase are used for the second enzymatic hydrolysis.

[0009] The European plum pulp fermentation step adopts terrestrial Issatchenkia terricola WJL-G4 fermentation.

[0010] The biological deposit information of the terrestrial Issatchenkia terricola WJL-G4 is: deposited in the General Microbiology Center of the China Culture Collection Administration on October 17, 2019, with a deposit number of CGMCC No. 18712, and the proposed classification name is: Terrestrial Issatchenkia terricola, the test result is alive, and the deposit address is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.

[0011] The specific operation details are as follows.

[0012] S1: removing impurities, washing, removing cores and crushing the Prunus cerasus fruits to obtain Prunus cerasus fruit pulp.

[0013] Select mature, pest-free Prunus chinensis fruits, remove impurities such as the stems, rinse with clean water, drain the surface moisture, and cut the fruit to remove the core. This will yield pitted Prunus chinensis. The pitted Prunus chinensis are then pulped using a juice blender to obtain a crude Prunus chinensis pulp. Disperse 10-15 kg of the crude Prunus chinensis pulp in a dual-shaft high-speed disperser at 15,000-20,000 rpm for 3-5 minutes to obtain the Prunus chinensis pulp.

[0014] S2: The prune pulp is subjected to a first enzymatic hydrolysis to obtain a primary enzymatic hydrolyzed prune pulp.

[0015] Pectinase is added at a weight percentage of 0.01-0.05% of the jujube fruit pulp, and the pectinase activity is 100,000 U / g. The mixture is then placed in a sealed thermostatic container at 40-45°C for enzymatic hydrolysis for 2-2.5 hours, and then the temperature is rapidly raised to 90°C to inactivate the enzyme for 5 minutes. The mixture is then pasteurized and cooled to room temperature to obtain a once-enzymatically hydrolyzed jujube fruit pulp.

[0016] S3: fermenting the European plum pulp to obtain fermented European plum pulp.

[0017] First, the activation of Issaffine yeast WJL-G4 was performed. A loop of bacterial sludge from the slant culture medium stored in a 4°C refrigerator was picked and inoculated into YPD liquid culture medium. The activation culture conditions were as follows: temperature 25-28°C, rotation speed 140-240 rpm, liquid volume 20-45 mL / 250 mL conical flask, and incubation time 24 h. The culture medium was then transferred to YPD liquid culture medium again. The inoculation volume ratio during transfer was 1-3%, the culture temperature was 25-28°C, the rotation speed was 140-240 rpm, the YPD liquid culture medium volume was 20-45 mL / 250 mL conical flask, and the incubation time was 16-28 h. Distilled water was then added and the viable bacterial count was adjusted to 1-5 × 10 8 CFU / mL, and the acid-reducing fermentation seed liquid was obtained.

[0018] The acid-reducing fermentation seed liquid obtained in step S1 is inoculated with the acid-reducing fermentation seed liquid and the primary enzymatic hydrolyzed Prunus cerasus pulp at a weight ratio of 5-10:100, and then acid-reducing fermentation is performed at 25-28° C. and 120-240 rpm for 40-48 hours to obtain fermented Prunus cerasus pulp. The primary enzymatic hydrolyzed Prunus cerasus pulp is filled in a volume of 30-50 mL / 250 mL conical flask, i.e., the liquid volume ratio is 12-20%.

[0019] S4: The fermented European plum pulp is enzymatically hydrolyzed for the second time to obtain a secondary enzymatically hydrolyzed European plum pulp.

[0020] The double shafts of the double-shaft high-speed disperser are sterilized with food-grade 75% (v / v) alcohol. 10-15 kg of fermented European plum pulp is dispersed at a speed of 10000-12000 rpm using the double-shaft high-speed disperser for 20-30 seconds. Then, cellulase with an enzyme activity of 100000 U / g is added according to a weight ratio of fermented European plum pulp to cellulase of 1000:1-2. The mixture is mixed evenly to dissolve and disperse the pulp. The temperature is raised to 40-45°C and the enzymatic hydrolysis is carried out in a sealed state for 2-2.5 hours.

[0021] The β-glucosidase with an enzyme activity of 30,000 U / g and the α-rhamnosidase with an enzyme activity of 50,000 U / g are evenly mixed in a weight ratio of 10:2-4 to obtain a mixed enzyme dry powder, and then the mixed enzyme is added to the pulp after cellulase hydrolysis in a weight ratio of 1,000:1-2 of the fermented European plum pulp and the mixed enzyme dry powder. Without inactivating the cellulase, the temperature is adjusted to 35-45°C, and the enzymatic hydrolysis is continued for 2.5-3.5 hours to obtain a secondary enzymatic hydrolysis European plum pulp.

[0022] S5: The prune pulp is subjected to secondary enzymatic hydrolysis and then filtered, sterilized, and bottled to obtain the prune juice product.

[0023] The secondary enzymatic hydrolysis of the jujube fruit pulp is subjected to enzyme inactivation, filtration, sterilization, and filling using conventional processes or methods to obtain the jujube fruit juice product. The product is then tested for indicators.

[0024] The measuring method used in the present invention is as follows.

[0025] Method for determining total acid: Use the second method in the national standard "National Food Safety Standard Determination of Total Acid in Food" (GB12456-2021), that is, the pH meter potentiometric titration method, for determination. The results are expressed as g / L based on citric acid.

[0026] Calcium determination method: Use the first method in the national standard "National Food Safety Standard Determination of Calcium in Food" (GB 5009.92-2016), namely flame atomic absorption spectrometry, for determination, and the results are expressed as mg / L.

[0027] Zinc determination method: Use the first method in the national standard "National Food Safety Standard Determination of Zinc in Food" (GB 5009.14-2017), namely flame atomic absorption spectrometry, for determination, and the results are expressed as mg / L.

[0028] Advantages of the present invention

[0029] The present invention utilizes a combined method of releasing the fruit with a high-speed disperser, enzymatic hydrolysis with pectinase, fermentation with terrestrial Issachus yeast, and co-enzymatic hydrolysis with cellulase, β-glucosidase, and α-rhamnosidase to produce a clear lychee juice product. While increasing yield, the product's taste is effectively improved, and the total acid content is significantly reduced. The resulting clear juice product, which is sweet and sour, clear, and full of lychee flavor, is obtained from high-acid raw materials. The calcium and zinc contents in the clear juice product are increased by 65% ​​and 59%, respectively, compared to products not treated using the combined method. The product has excellent calcium and zinc supplementation effects and is suitable for both young and old, with broad prospects. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0031] Example 1

[0032] A combined method for improving the taste of lychee juice and increasing the available calcium and zinc content, the operating steps comprising:

[0033] S1: removing impurities, washing, removing cores and crushing the Prunus cerasus fruits to obtain Prunus cerasus fruit pulp.

[0034] Select mature, pest-free Prunus chinensis fruits, remove impurities such as the stems, rinse with clean water, drain the surface moisture, and cut the fruit to remove the pits, obtaining 11 kg of pitted Prunus chinensis. After beating the pitted Prunus chinensis using a juice blender, 10.8 kg of crude Prunus chinensis pulp was obtained. This 10.8 kg of crude Prunus chinensis pulp was dispersed in a dual-shaft high-speed disperser at 15,000 rpm for 5 minutes, yielding 10.8 kg of Prunus chinensis pulp.

[0035] S2: The prune pulp is subjected to a first enzymatic hydrolysis to obtain a primary enzymatic hydrolyzed prune pulp.

[0036] Pectinase with an enzyme activity of 100,000 U / g was added at a weight ratio of 0.02% of the jujube pulp, and then placed in a constant temperature of 40°C for enzymatic hydrolysis for 2 hours, and then quickly heated to 90°C for enzyme inactivation for 5 minutes. After pasteurization, the mixture was cooled to room temperature to obtain a once enzymatic hydrolyzed jujube pulp.

[0037] S3: fermenting the European plum pulp to obtain fermented European plum pulp.

[0038] First, the activation of Issaffine yeast WJL-G4 was performed. A loop of bacterial sludge stored in a 4°C refrigerator was picked from the slant culture medium and inoculated into YPD liquid medium. The activation culture conditions were: temperature 28°C, rotation speed 240 rpm, liquid volume 45 mL / 250 mL conical flask, and incubation time 24 h. The culture medium was then transferred to YPD liquid medium again. The inoculation volume ratio during transfer was 1%, the culture temperature was 28°C, the rotation speed was 240 rpm, the YPD liquid medium liquid volume was 45 mL / 250 mL conical flask, and the incubation time was 16 h. Distilled water was then added to adjust the viable count to 1×10 8 CFU / mL, and the acid-reducing fermentation seed liquid was obtained.

[0039] The acid-reducing fermentation seed liquid obtained in step S1 was inoculated at a weight ratio of 5:100 between the acid-reducing fermentation seed liquid and the once enzymatically hydrolyzed European plum pulp, and then the acid-reducing fermentation was carried out for 48 hours at 28° C., 240 rpm, and a once enzymatically hydrolyzed European plum pulp filling volume of 45 mL / 250 mL conical flask to obtain fermented European plum pulp.

[0040] S4: The fermented European plum pulp is enzymatically hydrolyzed for the second time to obtain a secondary enzymatically hydrolyzed European plum pulp.

[0041] The fermented European plum pulp in each conical flask was combined to obtain 10.5 kg of fermented European plum pulp. The double shafts of the double-shaft high-speed disperser were sterilized with food-grade 75% (v / v) alcohol, and then dispersed at a speed of 12000 rpm for 30 seconds using a double-shaft high-speed disperser. After that, cellulase with an enzyme activity of 100000 U / g was added according to a weight ratio of fermented European plum pulp to cellulase of 1000:2. The mixture was mixed evenly to dissolve and disperse, the temperature was raised to 40°C, and enzymatic hydrolysis was carried out for 2 hours.

[0042] The β-glucosidase with an enzyme activity of 30,000 U / g and the α-rhamnosidase with an enzyme activity of 50,000 U / g were evenly mixed in a weight ratio of 5:1 to obtain a mixed enzyme dry powder. The mixed enzyme was then added to the pulp after cellulase hydrolysis in a weight ratio of 1,000:2 of the fermented European plum pulp and the mixed enzyme dry powder. Without inactivating the cellulase, the temperature was adjusted to 35°C, and the enzymatic hydrolysis was continued in a sealed manner for 2.5 hours to obtain 10.5 kg of secondary enzymatic European plum pulp.

[0043] S5: Secondary enzymatic hydrolysis of the European prune pulp, filtering, sterilization, and filling to obtain the European prune juice product.

[0044] The secondary enzymatic hydrolysis of the jujube pulp was inactivated, filtered, sterilized, and bottled, yielding 7.6 kg of jujube juice. The jujube juice was assayed according to national standards, revealing a total acidity of 4.56 g / L. The juice was sweet and sour, with a typical jujube flavor. Calcium and zinc contents were measured to be 575.92 mg / L and 3.88 mg / L, respectively. Compared to the jujube juice in Comparative Example 1, which was not treated with the combined method, the total acidity decreased by 70.9%, while the calcium and zinc contents increased by 65.18% and 59.02%, respectively.

[0045] Example 2

[0046] A combined method for improving the taste of lychee juice and increasing the available calcium and zinc content, the operating steps comprising:

[0047] S1: removing impurities, washing, removing cores and crushing the Prunus cerasus fruits to obtain Prunus cerasus fruit pulp.

[0048] Mature, pest-free Prunus chinensis fruits were selected, the stems and other impurities removed, the fruits washed with clean water, and the surface moisture drained. The pits were removed by incision, yielding 15 kg of pitted Prunus chinensis fruits. The pitted Prunus chinensis fruits were then blended in a juice blender to yield 14.7 kg of crude Prunus chinensis fruit pulp. This crude Prunus chinensis fruit pulp was then dispersed in a dual-shaft high-speed disperser at 20,000 rpm for 3 minutes, yielding 14.7 kg of Prunus chinensis fruit pulp.

[0049] S2: The prune pulp is subjected to a first enzymatic hydrolysis to obtain a primary enzymatic hydrolyzed prune pulp.

[0050] 7 g of pectinase with an enzyme activity of 100,000 U / g was added to 14.7 kg of European plum pulp, and then placed in a sealed container at a constant temperature of 45°C for enzymatic hydrolysis for 2.5 hours. The temperature was then rapidly raised to 90°C for enzyme inactivation for 5 minutes. After pasteurization, the mixture was cooled to room temperature to obtain a once enzymatically hydrolyzed European plum pulp.

[0051] S3: fermenting the European plum pulp to obtain fermented European plum pulp.

[0052] First, the activation of Issaffine yeast WJL-G4 was performed. A loop of bacterial sludge stored in a 4°C refrigerator was picked from the slant culture medium and inoculated into YPD liquid medium. The activation culture conditions were as follows: temperature of 25°C, rotation speed of 140 rpm, liquid volume of 30 mL / 250 mL conical flask, and incubation time of 24 h. The culture medium was then transferred to YPD liquid medium again. The inoculation volume ratio during transfer was 3%, the culture temperature was 25°C, the rotation speed was 140 rpm, the YPD liquid medium liquid volume was 30 mL / 250 mL conical flask, and the incubation time was 28 h. Distilled water was then added to adjust the viable count to 5×10 8 CFU / mL, and the acid-reducing fermentation seed liquid was obtained.

[0053] The acid-reducing fermentation seed liquid obtained in step S1 was inoculated with the acid-reducing fermentation seed liquid and the primary enzymatically hydrolyzed Prunus cerasus fruit pulp at a weight ratio of 10:100, and then acid-reducing fermentation was carried out at 28° C. and 200 rpm for 48 hours to obtain fermented Prunus cerasus fruit pulp. The primary enzymatically hydrolyzed Prunus cerasus fruit pulp was filled in a volume of 30 mL / 250 mL conical flask, i.e., the volume ratio was 12%.

[0054] S4: The fermented European plum pulp is enzymatically hydrolyzed for the second time to obtain a secondary enzymatically hydrolyzed European plum pulp.

[0055] The fermented European plum pulp obtained in step S3 was combined to obtain 14.5 kg of fermented European plum pulp. The double shafts of the double-shaft high-speed disperser were sterilized with food-grade 75% (v / v) alcohol. The fermented European plum pulp was dispersed at a speed of 12000 rpm for 20 seconds using a double-shaft high-speed disperser. After that, 14.5 g of cellulase with an enzyme activity of 100000 U / g was added according to a weight ratio of fermented European plum pulp to cellulase of 1000:1. The mixture was mixed evenly to dissolve and disperse, the temperature was raised to 45°C, and the enzymatic hydrolysis was carried out for 2.5 hours.

[0056] The β-glucosidase with an enzyme activity of 30,000 U / g and the α-rhamnosidase with an enzyme activity of 50,000 U / g were evenly mixed in a weight ratio of 10:4 to obtain a mixed enzyme dry powder. Then, 14.5 g of the mixed enzyme was added to the pulp after cellulase hydrolysis in a ratio of 1000:1 of the weight ratio of fermented European plum pulp to the weighed mixed enzyme dry powder. Without inactivating the cellulase, the temperature was adjusted to 40°C, and the enzymatic hydrolysis was continued for 3.5 hours to obtain a secondary enzymatic hydrolysis of European plum pulp.

[0057] S5: Secondary enzymatic hydrolysis of the European prune pulp, filtering, sterilization, and filling to obtain the European prune juice product.

[0058] The secondary enzymatic hydrolysis of the jujube pulp was subjected to enzyme inactivation, filtration, sterilization, and canning using conventional processes or methods to produce 10.2 kg of jujube juice. The jujube juice was assayed according to national standards, revealing a total acidity of 2.95 g / L. The juice was sweet and sour, with a typical jujube flavor. The calcium and zinc contents were determined to be 595.65 mg / L and 4.12 mg / L, respectively. Compared to the jujube juice in Comparative Example 1 that was not treated with the combined method, the total acidity decreased by 81.17%, while the calcium and zinc contents increased by 70.83% and 68.85%, respectively.

[0059] Example 3

[0060] A combined method for improving the taste of lychee juice and increasing the available calcium and zinc content, the operating steps comprising:

[0061] S1: removing impurities, washing, removing cores and crushing the Prunus cerasus fruits to obtain Prunus cerasus fruit pulp.

[0062] Mature, pest-free Prunus chinensis fruits were selected, the stems and other impurities removed, the fruits washed with clean water, and the surface moisture drained. The pits were removed by incision to obtain 11 kg of pitted Prunus chinensis fruits. The pitted Prunus chinensis fruits were pulped using a juice blender to obtain 10.8 kg of crude Prunus chinensis pulp, which was then dispersed using a dual-shaft high-speed disperser at 18,000 rpm for 4 minutes to obtain 10.8 kg of Prunus chinensis pulp.

[0063] S2: The prune pulp is subjected to a first enzymatic hydrolysis to obtain a primary enzymatic hydrolyzed prune pulp.

[0064] Pectinase was added at a weight ratio of 0.02% of the jujube pulp, with an activity of 100,000 U / g. The mixture was then placed in a sealed container at a constant temperature of 40°C for enzymatic hydrolysis for 2.5 hours, and then the temperature was rapidly raised to 90°C for enzyme inactivation for 5 minutes. The mixture was pasteurized and cooled to room temperature to obtain a once enzymatically hydrolyzed jujube pulp.

[0065] S3: fermenting the European plum pulp to obtain fermented European plum pulp.

[0066] A loop of bacterial slurry of terrestrial Issaffine WJL-G4 stored in a 4°C refrigerator was picked from the slant culture medium and inoculated into YPD liquid medium. The activation culture conditions were as follows: temperature of 26°C, rotation speed of 180 rpm, liquid volume of 45 mL / 250 mL conical flask, and incubation time of 24 h. The culture medium was then transferred to YPD liquid medium again. The inoculation volume ratio during transfer was 3%, the culture temperature was 26°C, the rotation speed was 180 rpm, the YPD liquid medium liquid volume was 45 mL / 250 mL conical flask, and the incubation time was 24 h. Distilled water was then added and the viable count was adjusted to 2.5 × 10 8 CFU / mL, and the acid-reducing fermentation seed liquid was obtained.

[0067] The acid-reducing fermentation seed liquid obtained in step S1 was inoculated at a weight ratio of 8:100 between the acid-reducing fermentation seed liquid and the primary enzymatically hydrolyzed Prunus cerasus pulp. The acid-reducing fermentation seed liquid was then fermented at 26° C. and 180 rpm for 44 hours to obtain fermented Prunus cerasus pulp. The primary enzymatically hydrolyzed Prunus cerasus pulp was loaded into a 250 mL conical flask at a volume of 45 mL.

[0068] S4: The fermented European plum pulp is enzymatically hydrolyzed for the second time to obtain a secondary enzymatically hydrolyzed European plum pulp.

[0069] The fermented European plum pulp was collected into a sterile container, totaling 10.6 kg. The double shafts of the double-shaft high-speed disperser were sterilized with food-grade 75% alcohol and dispersed at a speed of 11,000 rpm for 25 seconds using a double-shaft high-speed disperser. Then, 10.6 g of cellulase with an enzyme activity of 100,000 U / g was added according to a weight ratio of fermented European plum pulp to cellulase of 1,000:1. The mixture was mixed evenly to dissolve and disperse the pulp. The temperature was raised to 40°C and enzymatic hydrolysis was performed for 2.5 hours.

[0070] The β-glucosidase with an enzyme activity of 30,000 U / g and the α-rhamnosidase with an enzyme activity of 50,000 U / g were evenly mixed in a weight ratio of 10:3 to obtain a mixed enzyme dry powder. Then, 21.2 g of the mixed enzyme was added to the pulp after cellulase hydrolysis in a ratio of 1000:2 of the fermented European plum pulp to the weighed mixed enzyme dry powder. Without inactivating the cellulase, the temperature was maintained at 40°C, and the enzymatic hydrolysis was continued for 3.5 hours. Secondary enzymatic hydrolysis of European plum pulp was obtained.

[0071] S5: Secondary enzymatic hydrolysis of the European prune pulp, filtering, sterilization, and filling to obtain the European prune juice product.

[0072] The secondary enzymatic hydrolysis of the jujube pulp was subjected to enzyme inactivation, filtration, sterilization, and canning using conventional processes or methods to produce 7.52 kg of jujube juice. The jujube juice was assayed according to national standards, revealing a total acidity of 4.21 g / L. The juice was sweet and sour, with a typical jujube flavor. The calcium and zinc contents were determined to be 589.76 mg / L and 3.97 mg / L, respectively. Compared to the jujube juice in Comparative Example 1 that was not treated with the combined method, the total acidity decreased by 73.13%, while the calcium and zinc contents increased by 69.15% and 62.7%, respectively.

[0073] Comparative Example 1

[0074] The steps of obtaining the European juicy syrup include:

[0075] Select mature European plum fruits that are free of diseases and insect pests, remove impurities such as the fruit stalks, wash them with clean water, drain the surface moisture, cut and remove the cores, and obtain 11kg of cored European plums. After the cored European plums are pulped three times with a juice beater, 10.8kg of European plum pulp is obtained, which is then filtered, sterilized, and filled using conventional processes or methods to obtain 5.89kg of comparative European plum juice products. According to the national standard method, the indicators of the comparative European plum juice products were measured, and the total acidity was 15.67g / L. The juice has a typical European plum fruit aroma, but the sour taste is sharp and unacceptable. After measurement, the calcium and zinc contents were 348.67mg / L and 2.44mg / L, respectively.

[0076] The above descriptions are only some embodiments of the present invention and are not intended to limit the present invention. The scope of patent protection of the present invention shall be based on the claims. Any equivalent structural changes made using the contents of the description of the present invention shall also be included in the scope of protection of the present invention.

Claims

1. A combined method for improving the taste of lychee juice and increasing the available calcium and zinc content, the method comprising the following steps: S1: removing impurities, washing, removing cores, and crushing lychee fruits to obtain lychee pulp; S2: performing a first enzymatic hydrolysis on the lychee pulp to obtain a primary enzymatic hydrolyzed lychee pulp; S3: fermenting the lychee pulp to obtain a fermented lychee pulp; S4: performing a second enzymatic hydrolysis on the fermented lychee pulp to obtain a secondary enzymatic hydrolyzed lychee pulp; and S5: filtering, sterilizing, and bottling the secondary enzymatic hydrolyzed lychee pulp to obtain the lychee juice product. in, In S1, a high-speed disperser was used to crush the pulp, and the first enzymatic hydrolysis was performed using pectinase, and the second enzymatic hydrolysis was performed using cellulase, β-glucosidase, and α-rhamnosidase; The European plum pulp fermentation step adopts terrestrial Issatchenkia terricola WJL-G4 fermentation.

2. The combination method according to claim 1, wherein: In step S1, 10-15 kg of crude prune pulp is dispersed in a double-shaft high-speed disperser at a rotation speed of 15,000-20,000 rpm for 3-5 minutes.

3. The combination method according to claim 1, wherein: In step S2, pectinase with an enzyme activity of 100,000 U / g is added according to 0.01-0.05% by weight of the jujube pulp, and then placed in a sealed constant temperature container at 40-45°C for enzymatic hydrolysis for 2-2.5 hours to obtain a primary enzymatic hydrolyzed jujube pulp.

4. The combination method according to claim 1, wherein: In step S3, the acid-reducing fermentation seed liquid obtained in step S1 is inoculated at a weight ratio of 5-10:100 between the acid-reducing fermentation seed liquid and the once enzymatically hydrolyzed European plum pulp, and then the acid-reducing fermentation is carried out at 25-28° C. and 120-240 rpm for 40-48 hours to obtain fermented European plum pulp.

5. The combined method according to claims 1 and 4, characterized in that The liquid volume of the enzymatic hydrolysis of the European plum pulp is 30-50 mL / 250 mL conical flask, that is, the liquid volume ratio is 12-20%.

6. The combination method according to claim 1, wherein: In step S4, the fermented European plum pulp is dispersed at a speed of 10000-12000 rpm using a double-shaft high-speed disperser for 20-30 seconds, and then cellulase with an enzyme activity of 100000 U / g is added according to a weight ratio of fermented European plum pulp to cellulase of 1000:1-2, mixed evenly to dissolve and disperse, and the temperature is increased to 40-45°C, and the enzymatic hydrolysis is sealed for 2-2.5 hours.

7. The combination method according to claim 1, wherein: In step S4, the β-glucosidase with an enzyme activity of 30,000 U / g and the α-rhamnosidase with an enzyme activity of 50,000 U / g are mixed in a weight ratio of 10:2-4 to obtain a mixed enzyme dry powder, and then the mixed enzyme is added to the pulp after cellulase hydrolysis in a weight ratio of 1,000:1-2 of the fermented European plum pulp and the mixed enzyme dry powder. Without inactivating the cellulase, the temperature is adjusted to 35-45°C, and the enzymatic hydrolysis is continued for 2.5-3.5 hours to obtain a secondary enzymatic hydrolysis of the European plum pulp.

8. The lychee juice obtained by the combined method according to claim 1, characterized in that: After being treated by the combined method, the total acid content in the European juicy juice was significantly reduced, the juice was sweet and sour, and the calcium and zinc contents were increased by 65% ​​and 59% respectively compared with those not treated by the combined method.