Instant raspberry fruit powder and preparation method thereof

Abstract

The invention provides instant raspberry fruit powder and a preparation method thereof, and belongs to the technical field of food processing. The preparation method of the instant rubus corchorifolius fruit powder comprises the following steps: crushing rubus corchorifolius, homogenizing, heating the homogenate, and cooling; centrifuging the cooled homogenate for the first time to obtain a centrifugate 1, refrigerating and standing the centrifugate 1, centrifuging for the second time to obtain a centrifugate 2, and filtering the centrifugate 2 through a ceramic membrane to obtain a filtrate; and dehydrating the filtrate through a reverse osmosis membrane to obtain a concentrated solution, and carrying out vacuum concentration and drying on the concentrated solution to obtain the raspberry fruit powder. According to the method disclosed by the invention, the original flavor of rubus corchorifolius can be reserved to the greatest extent, the rubus corchorifolius has excellent water solubility and comfortable taste, and the defects and defects of the existing fruit powder production method are overcome.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to instant raspberry powder and a preparation method thereof. Background Art

[0002] Raspberries, also known as raspberries and blackberries, have bright colors, sweet and sour taste, and are rich in various nutrients. Raspberries are rich in antioxidants such as vitamin C, vitamin E, superoxide dismutase (SOD), and flavonoids, and have antioxidant, anti-aging, and immune-enhancing effects. In addition, raspberries are also rich in dietary fiber, which helps promote intestinal peristalsis and prevent constipation.

[0003] As a seasonal fruit, raspberry has a short supply period of fresh fruit and is not easy to store and transport. Traditional raspberry processing methods mainly include making jams, fruit wines, etc., but these products often add a lot of additives such as sugar and preservatives during the processing, which reduces the nutritional value and health value of raspberries. At the same time, the shape and taste of these products are relatively simple and cannot meet the diverse needs of consumers. In order to make full use of the nutritional value of raspberries, it is of great practical significance to develop a new type of raspberry processed product.

[0004] At present, there are many conventional methods for producing fruit powder, such as washing the fruit, peeling, removing the core, drying, crushing, and packaging. The fruit powder produced by this method can retain a small part of the original flavor, but the water solubility is extremely poor and the taste is poor; for example, the fruit and vegetables are added with water to squeeze the juice, filtered after decoction, clarified by sedimentation, concentrated under reduced pressure after high-temperature steam heating, and the concentrated liquid is spray-dried to prepare dry powder after adding excipients. The fruit powder produced by this method basically has no original flavor, and is easy to coke during the production process, has general water solubility, has some suspended matter, and has a poor taste; for example, the fruit and vegetables are washed, drained, cut, freeze-dried, and low-temperature crushed to obtain fruit powder. The fruit powder produced by this method can retain the original flavor to the greatest extent, but the microorganisms are high, the water solubility is extremely poor, and the taste is general. Therefore, the development of a raspberry fruit powder with high utilization rate of effective ingredients and good instant solubility is a technical problem that needs to be solved at this stage. Summary of the invention

[0005] In view of this, the object of the present invention is to provide an instant raspberry powder and a preparation method thereof, wherein the raspberry powder can retain the original flavor to the greatest extent, has excellent water solubility and a comfortable taste.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] The invention provides a preparation method of instant raspberry fruit powder, comprising the following steps: crushing raspberries into homogenate, heating the homogenate and then cooling it; centrifuging the cooled homogenate for the first time to obtain a centrifuge 1, refrigerating and standing the centrifuge 1, centrifuging for the second time to obtain a centrifuge 2, filtering the centrifuge 2 through a ceramic membrane to obtain a filtrate; dehydrating the filtrate through a reverse osmosis membrane to obtain a concentrated solution, vacuum concentrating the concentrated solution, and drying to obtain the raspberry fruit powder.

[0008] Preferably, the mass volume ratio of raspberries to water in the raspberry crushed homogenate is 1:0.5-2.

[0009] Preferably, the heating is to boiling and the temperature is kept for 5-15 minutes.

[0010] Preferably, the rotation speed of the first centrifugation is 3500-4500 rpm.

[0011] Preferably, the refrigerated storage temperature is 0-8°C and the time is greater than or equal to 48 hours.

[0012] Preferably, the second centrifugation speed is 10000-22000 rpm.

[0013] Preferably, the pore size of the ceramic membrane filtration is greater than or equal to 0.1 μm.

[0014] Preferably, the precipitate concentrate after ceramic membrane filtration is diluted with water, and the filtrate is collected by filtration.

[0015] Preferably, the temperature of the vacuum concentration is less than 55°C.

[0016] The invention provides instant raspberry powder obtained by the preparation method.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a method for preparing raspberry fruit powder for the first time, which comprises extracting effective ingredients after homogenizing and squeezing juice, removing suspended impurities through a ceramic membrane after refrigerated sedimentation, low-temperature concentration through an organic membrane, low-temperature concentration to collect a paste, and spray drying to prepare dry powder. The technical solution of this series of step combination can retain the original flavor of raspberry to the greatest extent, and has excellent water solubility and a comfortable taste, overcoming the shortcomings and defects of other existing fruit powder production methods. The method is simple to operate, has low production cost, good product quality, and is suitable for large-scale industrial production.

[0019] Furthermore, the raspberry fruit powder prepared by the present invention is easily soluble in water without precipitation, can pass 100% through an 80-mesh sieve, has uniform particle size, has no methanol and ethanol residue, does not need to add other additives, and can be directly taken with warm water. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1The figure is a flow chart for the preparation of instant raspberry powder. DETAILED DESCRIPTION

[0021] The present invention provides a method for preparing instant raspberry fruit powder, comprising the following steps: crushing raspberries into homogenate, heating the homogenate and then cooling it; centrifuging the cooled homogenate for the first time to obtain centrifuge 1, refrigerating and standing the centrifuge 1, centrifuging for the second time to obtain centrifuge 2, filtering the centrifuge 2 through a ceramic membrane to obtain a filtrate; dehydrating the filtrate through a reverse osmosis membrane to obtain a concentrate, vacuum concentrating the concentrate, and drying to obtain raspberry fruit powder. The present invention extracts effective ingredients after homogenization and juicing, removes suspended impurities through a ceramic membrane after refrigeration and sedimentation, and then concentrates at low temperature through an organic membrane to collect a paste, and spray-drying to prepare a dry powder. The technical solution of the combination of the series of steps can retain the original flavor to the greatest extent, and has excellent water solubility and a comfortable taste, overcoming the shortcomings and defects of other existing fruit powder production methods.

[0022] In the present invention, the mass volume ratio of raspberries to water in the raspberry crushing homogenate is 1:0.5-2, preferably 1:0.8-1.5, and more preferably 1:1. The raspberries used in the present invention are ripe raspberry fruits. Before the raspberries are crushed and homogenized, the present invention needs to sort the picked ripe raspberries to remove impurities, then wash them with deionized water, and then wash them with secondary reverse osmosis pure water (σ<2μs / cn). The number of washing times in the present invention is not less than 2 times.

[0023] In the present invention, the heating to boiling and keeping warm is 5-15 minutes, preferably 8-13 minutes, and more preferably 10 minutes. The purpose of the present invention heating the homogenate to boiling and keeping warm is to extract nutrients as much as possible and maximize the content of effective ingredients. The present invention requires that the slurry after heating, boiling and keeping warm is quickly cooled, and then centrifuged to remove the pomace. The purpose of the rapid cooling treatment of the present invention is to avoid the destruction of anthocyanins and product discoloration under long-term high temperature.

[0024] In the present invention, the cooled homogenate is centrifuged for the first time to obtain the centrifuge 1. The rotation speed of the first centrifugation in the present invention is 3500-4500 rpm; preferably, the rotation speed of the centrifugation is 3800-4200 rpm; more preferably, the rotation speed is 4000 rpm.

[0025] In the present invention, the centrifuge 1 obtained by the first centrifugation is placed in a refrigerated state at 0-8°C for more than or equal to 48 hours. The temperature of the refrigerated state of the present invention is preferably 2-4°C, and the time is preferably 48-72 hours; the temperature of the refrigerated state is further preferably 2°C, and the time is further preferably 48 hours. The purpose of the refrigerated state of the centrifuge in the present invention is to precipitate impurities in the solution at low temperature, such as tannins, proteins, etc.

[0026] In the present invention, the centrifuge 1 is subjected to a high-speed second centrifugation to obtain the centrifuge 2. The second centrifugation speed of the present invention is 10000-22000 rpm; preferably, the centrifugation speed is 12000-20000 rpm; more preferably, the speed is 16000 rpm.

[0027] In the present invention, the centrifuge 2 is filtered through a ceramic membrane of greater than or equal to 0.1 μm, and then the filtered precipitation slurry is replaced with pure water of a reverse osmosis membrane (RO membrane) and the filtrate is collected and combined with the ceramic membrane filtrate to proceed to the next step. The pore size of the ceramic membrane filtration of the present invention is preferably 0.3-0.1 μm, and more preferably 0.1 μm. The purpose of using ceramic membrane filtration in the present invention is to filter out suspended particles and make the solution clear and transparent. The reverse osmosis membrane of the present invention is a 115-205mwco RO membrane, preferably a 200mwco RO membrane.

[0028] In the present invention, the filtrate collected in the ceramic membrane filtration step is dehydrated and concentrated by a reverse osmosis membrane, and then vacuum dried at a vacuum degree of -0.05 to 0.15 mPa and a temperature of <55°C. The reverse osmosis membrane of the present invention can retain a molecular weight greater than 100 and allow water molecules to pass through. The vacuum degree of the vacuum concentration of the present invention is preferably -0.098 mPa, and the temperature is preferably <55°C. The present invention spray-dries the concentrated liquid, and then the dried and crushed raspberry fruit powder is mixed and sieved and packaged under the conditions of an 80-mesh sieve, an environment not lower than a Class D clean area, a temperature of 18-20°C, and a humidity of less than 30%.

[0029] The present invention also provides instant raspberry fruit powder obtained by the preparation method. The instant raspberry fruit powder of the present invention has a moisture content of less than 3%, a particle size of less than 180 μm, a total heavy metal content of less than 5 ppm, no pesticide residue detected, an anthocyanin content of not less than 0.5% (UV), a solubility in warm water less than 30° C. of ≥10 g / 100 ml, no suspended impurities, no methanol residue detected, and no ethanol residue detected.

[0030] In the present invention, unless otherwise specified, all components or reagents are commercially available products well known to those skilled in the art.

[0031] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] A method for preparing instant raspberry powder, comprising the following steps:

[0034] (1) Take 100 kg of mature raspberry fruits, select and remove impurities, first wash them with deionized water, then wash them with secondary reverse osmosis pure water (σ<2μs / cn), transfer them to a high-speed homogenizer, and add 100 kg of pure water for homogenization (36000rpm).

[0035] (2) The homogenate was transferred into a 300 L multifunctional extraction tank, heated to a boil and kept warm for 10 min, rapidly cooled, and centrifuged (4000 rpm) to remove the pomace to obtain 180 L of centrifuge; the centrifuge was placed in a 0-8°C cold storage for 48 h, and then transferred into a high-speed centrifuge (16000 rpm, fs=11000) to obtain centrifuge.

[0036] (3) The centrifuged liquid is filtered through a 0.1 μm ceramic membrane to collect the filtrate, and then the filtered precipitate concentrate is diluted with pure water and filtered again to collect the filtrate, and the filtrate is mixed.

[0037] (4) The filtrate was dehydrated through a 200mwco RO membrane (reverse osmosis membrane) to obtain a concentrated solution, and the concentrated solution was further concentrated at low temperature (vacuum degree -0.098mPa, T<55°C) to obtain a paste of 10kg, which was then spray-dried to obtain 3.7kg of dry powder.

[0038] Example 2

[0039] A method for preparing instant raspberry powder, comprising the following steps:

[0040] (1) Take 100 kg of mature raspberry fruits, select and remove impurities, first wash them with deionized water, then wash them with secondary reverse osmosis pure water (σ<2μs / cn), transfer them to a high-speed homogenizer, and add 80 kg of pure water for homogenization (36000 rpm).

[0041] (2) The homogenate was transferred into a 300 L multifunctional extraction tank, heated to a boil and kept warm for 5 min, rapidly cooled, and centrifuged (3500 rpm) to remove the pomace to obtain 180 L of centrifuge; the centrifuge was placed in a 0-8°C cold storage for 48 h, and then transferred into a high-speed centrifuge (10000 rpm, fs=11000) to obtain centrifuge.

[0042] (3) The centrifuged liquid is filtered through a 0.2 μm ceramic membrane to collect the filtrate, and then the filtered precipitate concentrate is diluted with pure water and filtered again to collect the filtrate, and the filtrate is mixed.

[0043] (4) The filtrate was dehydrated through a 200mwco RO membrane (reverse osmosis membrane) to obtain a concentrated solution, and the concentrated solution was further concentrated at low temperature (vacuum degree -0.098mPa, T<55°C) to obtain a paste of 10kg, which was then spray-dried to obtain 3.1kg of dry powder.

[0044] Example 3

[0045] A method for preparing instant raspberry powder, comprising the following steps:

[0046] (1) 100 kg of ripe raspberry fruits were selected to remove impurities, first washed with deionized water, then washed with secondary reverse osmosis pure water (σ<2μs / cn), transferred to a high-speed homogenizer, and 200 kg of pure water was added for homogenization (36000 rpm).

[0047] (2) The homogenate was transferred into a 300 L multifunctional extraction tank, heated to a boil and kept warm for 15 min, rapidly cooled, and centrifuged (4500 rpm) to remove the pomace to obtain 180 L of centrifuge; the centrifuge was placed in a 0-8°C cold storage for 48 h, and then transferred into a high-speed centrifuge (22000 rpm, fs=11000) to obtain centrifuge.

[0048] (3) The centrifuged liquid is filtered through a 0.3 μm ceramic membrane to collect the filtrate, and then the filtered precipitate concentrate is diluted with pure water and filtered again to collect the filtrate, and the filtrate is mixed.

[0049] (4) The filtrate was dehydrated through a 200mwco RO membrane (reverse osmosis membrane) to obtain a concentrated solution, and the concentrated solution was further concentrated at low temperature (vacuum degree -0.098mPa, T<55°C) to obtain a paste of 10kg, which was then spray-dried to obtain 3.4kg of dry powder.

[0050] Comparative Example 1

[0051] (1) Take 10 kg of ripe raspberry fruits, select and remove impurities, wash them with drinking water, transfer them into a high-speed homogenizer, add 10 kg of water and homogenize them (36000 rpm).

[0052] (2) The homogenate was transferred into a 50 L multifunctional extraction tank, heated to a boil and kept warm for 15 min, rapidly cooled, centrifuged (4500 rpm) to remove the pomace to obtain the centrifuge, and then the centrifuge was transferred into a high-speed centrifuge (22000 rpm, fs=11000) for centrifugation to collect the centrifuge.

[0053] (3) The centrifuged liquid was dehydrated through a 200mwco RO membrane (reverse osmosis membrane) to obtain a concentrated liquid, which was then concentrated at low temperature to obtain a paste (vacuum degree -0.098mPa, T<55°C), and spray-dried to obtain 0.48kg of dry powder.

[0054] Result analysis: The raspberry powder prepared by this process had a lot of precipitation when it was re-dissolved in room temperature water, and its solubility was poor. The reason was that the first centrifuge liquid was refrigerated and static and the ceramic membrane filtration step was not performed.

[0055] Comparative Example 2

[0056] (1) Take 10 kg of ripe raspberry fruits, select and remove impurities, wash them with drinking water, transfer them into a high-speed homogenizer, add 10 kg of water and homogenize them (36000 rpm).

[0057] (2) The homogenate was transferred into a 50 L multifunctional extraction tank, heated to a boil and kept warm for 15 min, rapidly cooled, centrifuged (4500 rpm) to remove the pomace to obtain the centrifuge, and then the centrifuge was transferred into a high-speed centrifuge (22000 rpm, fs=11000) for centrifugation to collect the centrifuge.

[0058] (3) The centrifuged liquid was filtered through a 0.3 μm ceramic membrane to collect the filtrate, and the ceramic membrane filtrate was dehydrated through a 200 mwco RO membrane (reverse osmosis membrane) to obtain a concentrate, and the concentrate was further concentrated at low temperature (vacuum degree -0.098 mPa, T < 55°C) to obtain a paste, and spray dried to obtain 0.43 kg of dry powder.

[0059] Result analysis: The raspberry powder prepared by this process had a small amount of suspended precipitation when it was re-dissolved in room temperature water and failed to dissolve completely. The reason was that the first centrifuge liquid refrigeration and standing step was omitted.

[0060] Experimental Example 1

[0061] The properties of the dry powder prepared in Examples 1-3 were observed, and the solubility, moisture, particle size, anthocyanin, total heavy metals, methanol residue, ethanol residue, pesticide residue and yield were measured with reference to the relevant determination methods of the Pharmacopoeia of the People's Republic of China. At the same time, the same method as above was used to detect the indicators of the raspberry powder of Comparative Example 1 and Comparative Example 2. The results are shown in Table 1.

[0062] Table 1 Test results of indicators of raspberry powder

[0063]

[0064] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing instant raspberry powder, characterized in that: The steps include: Crush the raspberries into a homogenate, heat the homogenate and then cool it; The cooled homogenate is centrifuged for the first time to obtain centrifuge 1, the centrifuge 1 is refrigerated and allowed to stand, the centrifuge is centrifuged for the second time to obtain centrifuge 2, and the centrifuge 2 is filtered through a ceramic membrane to obtain a filtrate; The filtrate is dehydrated through a reverse osmosis membrane to obtain a concentrated solution, and the concentrated solution is vacuum concentrated and dried to obtain raspberry powder.

2. The preparation method according to claim 1, characterized in that The mass volume ratio of raspberries to water in the raspberry crushing homogenate is 1:0.5-2.

3. The preparation method according to claim 1, characterized in that: The heating is to boiling and kept warm for 5-15 minutes.

4. The preparation method according to claim 1, characterized in that: The rotation speed of the first centrifugation is 3500-4500 rpm.

5. The preparation method according to claim 1, characterized in that: The temperature of the refrigerated storage is 0-8°C, and the time is greater than or equal to 48 hours.

6. The preparation method according to claim 1, characterized in that: The rotation speed of the second centrifugation is 10000-22000 rpm.

7. The preparation method according to claim 1, characterized in that: The pore size of the ceramic membrane filtration is greater than or equal to 0.1 μm.

8. The preparation method according to claim 1, characterized in that: The precipitate concentrate after ceramic membrane filtration is diluted with water, and the filtrate is collected by filtration.

9. The preparation method according to claim 1, characterized in that: The temperature of the vacuum concentration is <55°C.

10. Instant raspberry powder obtained by the preparation method according to any one of claims 1 to 9.

Images