Method for preparing citrus fibers from citrus residues

Abstract

The invention discloses a method for preparing citrus fibers from citrus residues. The method comprises the following steps: S1, providing citrus pulp; s2, pretreating the citrus pulp; s3, adding petroleum ether and ethanol to carry out deoiling and decolorizing treatment on the citrus pulp; s4, performing drying, performing crushing and performing sieving so as to obtain bitter-free and light-yellow citrus powder; and S5, carrying out modification treatment on the citrus powder, and then carrying out grinding treatment to obtain the citrus fiber with a loose porous structure. The bitter taste of the orange peel is overcome, the taste of the orange fiber product is improved, the palatability is improved, the appearance of the orange fiber product is improved, the product quality is improved, the orange fiber with a loose and porous structure can be prepared through the method, the method has a positive effect on delaying glucose diffusion, and the health care product prepared from the orange fiber is better in health care effect and better in health care effect. Moreover, due to the loose and porous structure, the water absorption and expansibility of the citrus fibers are improved, and the processing adaptability is better.

Description

Technical Field

[0001] The invention relates to the technical field of citrus fiber production, in particular to a method for producing citrus fiber from citrus residues. Background Art

[0002] Citrus pulp is a product obtained by drying and crushing the remaining pulp, pits, peels, and discarded inferior fruits and inferior canned goods when citrus fruits (including sour oranges, grapefruits, and sweet oranges) are used as raw materials to produce juice and canned goods. There is a large amount of citrus fiber in the citrus pulp, which contains rich biologically active ingredients such as vitamin C, polyphenols, and flavonoids, and is widely used. For example, when citrus fiber is made into feed, it can provide a lot of energy for the growth of livestock such as beef cattle, and reduce the probability of acidosis and flatulence. For example, WHO stipulates that the amount of dietary fiber that the human body needs to consume every day is 16 to 24g / person, but most people are far from this standard. Therefore, citrus fiber is used to make edible cellulose powder, which is used in health products to help users supplement dietary fiber.

[0003] Reference is now made to the invention patent with application number 201810106852.7, which is a process for preparing citrus fiber from the residue after pectin extraction. The process uses an alkaline solution to treat the pomace, and then adds sodium carboxymethyl cellulose for emulsification and stabilization to produce the citrus fiber. The aforementioned patent has the following problems: the oil in the pomace is not removed, resulting in the presence of limonin-like bitter substances in the prepared citrus fiber, which affects the palatability of the prepared citrus fiber product. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing citrus fiber from citrus residue to overcome the bitterness of orange peel, improve the taste of citrus fiber products, enhance palatability, and prepare citrus fiber with a loose porous structure.

[0005] A method for preparing citrus fiber from citrus residues comprises the following steps:

[0006] S1 provided citrus pulp;

[0007] S2 pre-treats the citrus pulp;

[0008] S3 adds petroleum ether and ethanol to deoil and decolorize the citrus residue;

[0009] S4 is dried, crushed and sieved to obtain a non-bitter, light yellow citrus powder;

[0010] S5 modifies citrus powder and then grinds it to obtain citrus fiber with a loose porous structure.

[0011] In one embodiment, the remaining pulp, core, peel, discarded inferior fruit, inferior canned food, etc. when producing juice and canned food using citrus fruits as raw materials are dried and then crushed to obtain the citrus residue; the citrus fruits include sour oranges, grapefruits and sweet oranges.

[0012] In one embodiment, the specific operation of the pretreatment is as follows: soak the citrus pulp in water, add salt water and boil for 20 to 25 minutes, and then rinse with cold water for 1.5 to 2 hours; the concentration of the salt water is 0.9%. In the present invention, the salt water is used to inhibit bacteria and play a role in preservation, and the purpose of rinsing is to remove the residual salt water.

[0013] In one embodiment, the deoiling and decolorizing method is specifically performed as follows: petroleum ether, ethanol and pretreated citrus residue are stirred and mixed at 35-45°C for 2-3 hours, then subjected to microwave irradiation for 1 minute, and then heated to 60-80°C and distilled for 20-30 minutes.

[0014] Furthermore, the volume ratio of petroleum ether to ethanol is 1:1, and the power of the microwave radiation is 300-400W. Since the oil of citrus residue contains bitter substances such as limonin, which affects the palatability of the prepared citrus fiber product, the present invention uses petroleum ether to remove the oil from the citrus residue, and combines microwave radiation to accelerate the oil removal process, thereby overcoming the bitterness of orange peel, improving the taste of citrus fiber products, and improving palatability. In the present invention, ethanol is added for decolorization to improve the appearance of citrus fiber products and improve product quality.

[0015] In one embodiment, the drying is performed in a constant temperature oven, and the working temperature of the constant temperature oven is 50-60° C. In the present invention, the citrus material is dried by drying so that the water content thereof is less than 10%.

[0016] In one embodiment, the modification method is specifically performed as follows:

[0017] Step 1: Mix citrus powder and hydrogen peroxide solution, adjust the pH to 10-12, and keep warm at 45-55°C for 2-3 hours;

[0018] Step 2: Centrifuge at 4000-5000 rpm for 10-20 min, discard the supernatant and retain the precipitate.

[0019] Furthermore, the w / v ratio of the citrus powder to the hydrogen peroxide solution is 1:20-25, and the concentration of the hydrogen peroxide solution is 1-2%. The present invention removes some cellulose, hemicellulose, lignin and other components in the citrus material through the hydrogen peroxide solution, making the fiber product loose and porous, thereby improving the water absorption and expansion of the dietary fiber.

[0020] In one embodiment, the grinding method is specifically performed as follows: drying the precipitate, and then mechanically grinding it to obtain citrus fiber. The present invention performs dry surface treatment based on grinding, so that the average particle size of the citrus fiber decreases, the specific surface area increases, and the agglomerated particles of the citrus fiber are depolymerized, so that more hydrophilic groups are exposed on the surface of the citrus fiber, thereby improving its water absorption and making the fiber structure more loose and porous.

[0021] In one embodiment, the drying process is carried out in a dryer until the drying reaches a constant weight, and the drying temperature is 60-70°C; the grinding speed of the mechanical grinding is 500-1000r / min, and the time is 2-5h.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The invention uses petroleum ether to remove oil from citrus residues, combines microwave radiation to accelerate the oil removal process, thereby overcoming the bitterness of orange peel, improving the taste of citrus fiber products, and improving the palatability; ethanol is added for decolorization to improve the appearance of the citrus fiber products and improve the product quality.

[0024] The present invention can produce citrus fibers with a loose and porous structure. The fiber particles act as a physical barrier for glucose molecules and retain glucose in the fiber-formed network. When the fiber structure becomes loose and porous, exposing more surface functional groups, the interaction between the fiber and glucose is enhanced, thereby having a positive effect on delaying the diffusion of glucose. The health care products made from the citrus fibers have better health care effects. In addition, due to the looseness and porosity, the water absorption and expansion properties of the citrus fibers are improved, and the processing adaptability is better. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. Additional aspects and advantages of the present invention will be given in part in the following description, and will become apparent from the following description, or will be understood through the practice of the present invention. It should be understood that the following description is only used to explain the present invention and is not intended to limit the present invention.

[0026] As used herein, the terms "comprises," "including," "contains," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0027] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range limited by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including a range of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. When a numerical range is described in this article, unless otherwise specified, the range is intended to include its end values ​​and all integers and fractions within the range.

[0028] The specific embodiments of the present invention are described in detail below.

[0029] Example 1

[0030] This embodiment provides a method for preparing citrus fiber from citrus residues, which comprises the following steps:

[0031] S1 provides the citrus pulp obtained by drying and crushing the remaining pulp, pits, peels, discarded inferior fruits, inferior cans, etc. when producing juice and canned food using sour orange as raw materials;

[0032] S2 Soak the citrus pulp in water, add 0.9% salt water and boil for 20 minutes, then rinse with cold water for 1.5 hours to remove the residual salt water.

[0033] S3: petroleum ether, ethanol and pretreated citrus pulp were stirred and mixed at 35°C for 3 hours, then microwaved for 1 minute, and then heated to 60°C for distillation for 30 minutes to deoil and decolorize the citrus pulp. The volume ratio of petroleum ether to ethanol was 1:1, and the power of microwave radiation was 300W.

[0034] In this embodiment, petroleum ether is used to remove the oil from the citrus residue, and microwave radiation is combined to accelerate the oil removal process, thereby overcoming the bitterness of the orange peel, improving the taste of the citrus fiber product, and improving the palatability. Ethanol is added for decolorization to improve the appearance of the citrus fiber product and improve the product quality.

[0035] S4 drying, crushing and sieving to obtain a bitter-free, light yellow citrus powder. The drying is performed in a constant temperature oven, and the working temperature of the constant temperature oven is 50°C.

[0036] S5 modifies citrus powder and then grinds it to obtain citrus fiber with a loose porous structure.

[0037] In this embodiment, the cellulose, hemicellulose, lignin and other components in the citrus material are partially removed by modification with hydrogen peroxide solution, so that the fiber product is loose and porous inside, thereby improving the water absorption and swelling of the dietary fiber. The specific operation of the modification treatment method is as follows:

[0038] Step 1: Mix citrus powder and hydrogen peroxide solution, adjust the pH to 10, and keep warm at 45° C. for 2 hours. The w / v ratio of citrus powder to hydrogen peroxide solution is 1:20, and the concentration of hydrogen peroxide solution is 1%.

[0039] Step 2: Centrifuge at 4000 rpm for 20 min, discard the supernatant and retain the precipitate.

[0040] In this embodiment, dry surface treatment is performed based on grinding, so that the average particle size of citrus fiber decreases, the specific surface area increases, and the agglomerated particles of citrus fiber are depolymerized, so that more hydrophilic groups are exposed on the surface of citrus fiber, thereby improving its water absorption, and the fiber structure becomes looser and more porous. The method of the grinding treatment is specifically operated as follows: the precipitate is dried, and then mechanically ground to obtain citrus fiber. The drying treatment is carried out in a dryer until it is dried to constant weight, and the drying temperature is 60°C. The grinding speed of the mechanical grinding is 500r / min, and the time is 5h.

[0041] Example 2

[0042] This embodiment provides a method for preparing citrus fiber from citrus residues, which comprises the following steps:

[0043] S1 provides the citrus pulp obtained by drying and crushing the remaining pulp, pits, peels, discarded inferior fruits, inferior cans, etc. when producing juice and canned food using grapefruit as raw materials;

[0044] S2: Soak the citrus pulp in water, add 0.9% salt water and boil for 22 minutes, then rinse with cold water for 1.8 hours to remove the residual salt water;

[0045] S3: petroleum ether, ethanol and pretreated citrus pulp are stirred and mixed at 40°C for 2-3 hours, then microwaved for 1 minute, and then heated to 70°C for distillation for 25 minutes to deoil and decolorize the citrus pulp. The volume ratio of petroleum ether to ethanol is 1:1, and the power of microwave radiation is 350W.

[0046] In this embodiment, petroleum ether is used to remove the oil from the citrus residue, and microwave radiation is combined to accelerate the oil removal process, thereby overcoming the bitterness of the orange peel, improving the taste of the citrus fiber product, and improving the palatability. Ethanol is added for decolorization to improve the appearance of the citrus fiber product and improve the product quality.

[0047] S4 drying, crushing and sieving to obtain a bitter-free, light yellow citrus powder. The drying is performed in a constant temperature oven, and the working temperature of the constant temperature oven is 55°C.

[0048] S5 modifies citrus powder and then grinds it to obtain citrus fiber with a loose porous structure.

[0049] In this embodiment, the cellulose, hemicellulose, lignin and other components in the citrus material are partially removed by modification with hydrogen peroxide solution, so that the fiber product is loose and porous inside, thereby improving the water absorption and swelling of the dietary fiber. The specific operation of the modification treatment method is as follows:

[0050] Step 1: Mix citrus powder and hydrogen peroxide solution, adjust the pH to 11, and keep warm at 50° C. for 2.5 hours. The w / v ratio of citrus powder to hydrogen peroxide solution is 1:23, and the concentration of hydrogen peroxide solution is 1.5%.

[0051] Step 2: Centrifuge at 4500 rpm for 15 min, discard the supernatant and retain the precipitate.

[0052] In this embodiment, dry surface treatment is performed based on grinding, so that the average particle size of citrus fiber decreases, the specific surface area increases, and the agglomerated particles of citrus fiber are depolymerized, so that more hydrophilic groups are exposed on the surface of citrus fiber, thereby improving its water absorption, and the fiber structure becomes looser and more porous. The method of the grinding treatment is specifically operated as follows: the precipitate is dried, and then mechanically ground to obtain citrus fiber. The drying treatment is carried out in a dryer until it is dried to constant weight, and the drying temperature is 65°C. The grinding speed of the mechanical grinding is 800r / min, and the time is 4h.

[0053] Example 3

[0054] This embodiment provides a method for preparing citrus fiber from citrus residues, which comprises the following steps:

[0055] S1 provides the citrus pulp obtained by drying and crushing the remaining pulp, pits, peels, discarded inferior fruits, inferior cans, etc. when producing juice and canned food using sweet orange as raw materials;

[0056] S2: Soak the citrus pulp in water, add 0.9% salt water and boil for 25 minutes, then rinse with cold water for 2 hours to remove the residual salt water;

[0057] S3: petroleum ether, ethanol and pretreated citrus pulp are stirred and mixed at 45°C for 2 hours, then microwaved for 1 minute, and then heated to 80°C for distillation for 20 minutes to deoil and decolorize the citrus pulp. The volume ratio of petroleum ether to ethanol is 1:1, and the power of the microwave radiation is 400W.

[0058] In this embodiment, petroleum ether is used to remove the oil from the citrus residue, and microwave radiation is combined to accelerate the oil removal process, thereby overcoming the bitterness of the orange peel, improving the taste of the citrus fiber product, and improving the palatability. Ethanol is added for decolorization to improve the appearance of the citrus fiber product and improve the product quality.

[0059] S4 drying, crushing and sieving to obtain a bitter-free, light yellow citrus powder. The drying is carried out in a constant temperature oven, and the working temperature of the constant temperature oven is 60°C.

[0060] S5 modifies citrus powder and then grinds it to obtain citrus fiber with a loose porous structure.

[0061] In this embodiment, the cellulose, hemicellulose, lignin and other components in the citrus material are partially removed by modification with hydrogen peroxide solution, so that the fiber product is loose and porous inside, thereby improving the water absorption and swelling of the dietary fiber. The specific operation of the modification treatment method is as follows:

[0062] Step 1: Mix citrus powder and hydrogen peroxide solution, adjust the pH to 12, and keep warm at 55° C. for 3 hours. The w / v ratio of citrus powder to hydrogen peroxide solution is 1:25, and the concentration of hydrogen peroxide solution is 2%.

[0063] Step 2: Centrifuge at 5000 rpm for 10 min, discard the supernatant and retain the precipitate.

[0064] In this embodiment, dry surface treatment is performed based on grinding, so that the average particle size of citrus fiber decreases, the specific surface area increases, and the agglomerated particles of citrus fiber are depolymerized, so that more hydrophilic groups are exposed on the surface of citrus fiber, thereby improving its water absorption and making the fiber structure more loose and porous. The method of the grinding treatment is specifically performed as follows: the precipitate is dried and then mechanically ground to obtain citrus fiber. The drying treatment is carried out in a dryer until it is dried to constant weight, and the drying temperature is 70°C. The grinding speed of the mechanical grinding is 1000r / min, and the time is 2h.

[0065] The above embodiments are merely preferred implementations of the present invention. Any simple modification, amendment and substitution of the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for producing citrus fiber from citrus residues, It is characterized in that The following steps are involved: S1 provided citrus pulp; S2 pre-treats the citrus pulp; S3 adds petroleum ether and ethanol to deoil and decolorize the citrus residue; S4 is dried, crushed and sieved to obtain a non-bitter, light yellow citrus powder; S5 modifies citrus powder and then grinds it to obtain citrus fiber with a loose porous structure.

2. The method for producing citrus fiber from citrus residues according to claim 1, It is characterized in that The citrus pulp is obtained by drying and crushing the remaining pulp, core, peel, discarded inferior fruit, inferior canned food, etc. when producing juice and canned food using citrus fruits as raw materials to obtain the citrus residue; The citrus fruits include limes, grapefruits and sweet oranges.

3. The method for producing citrus fiber from citrus residues according to claim 1, It is characterized in that The specific operation of the pretreatment is as follows: soak the citrus residue in water, add salt water and boil for 20 to 25 minutes, and then rinse with cold water for 1.5 to 2 hours; The concentration of the brine was 0.9%.

4. The method for producing citrus fiber from citrus residues according to claim 1, It is characterized in that The deoiling and decolorizing method is specifically operated as follows: petroleum ether, ethanol and pretreated citrus residue are stirred and mixed for 2 to 3 hours at 35 to 45° C., then subjected to microwave irradiation for 1 minute, and then heated to 60 to 80° C. and distilled for 20 to 30 minutes.

5. The method for producing citrus fiber from citrus residues according to claim 4, It is characterized in that The volume ratio of petroleum ether to ethanol is 1:1, and the power of the microwave radiation is 300-400W.

6. The method for producing citrus fiber from citrus residues according to claim 1, It is characterized in that The drying is carried out in a constant temperature oven, and the working temperature of the constant temperature oven is 50-60°C.

7. The method for producing citrus fiber from citrus residues according to claim 1, It is characterized in that The modification method is specifically performed as follows: Step 1: Mix citrus powder and hydrogen peroxide solution, adjust the pH to 10-12, and keep warm at 45-55°C for 2-3 hours; Step 2: Centrifuge at 4000-5000 rpm for 10-20 min, discard the supernatant and retain the precipitate.

8. The method for producing citrus fiber from citrus residues according to claim 7, It is characterized in that The w / v ratio of the citrus powder to the hydrogen peroxide solution is 1:20-25, and the concentration of the hydrogen peroxide solution is 1-2%.

9. The method for producing citrus fiber from citrus residues according to claim 8, It is characterized in that The grinding method has the following specific operations: drying the precipitate, and then mechanically grinding it to obtain citrus fiber.

10. The method for producing citrus fiber from citrus residues according to claim 9, It is characterized in that The drying process is carried out in a drying machine until the drying reaches a constant weight, and the drying temperature is 60-70°C; The grinding speed of the mechanical grinding is 500-1000 r / min, and the time is 2-5 hours.