Processing method for enhancing oil adsorption capacity of asparagus crude fiber powder

Abstract

The application belongs to the technical field of asparagus rough fiber modification, and particularly relates to a processing method for enhancing the oil adsorption capacity of asparagus rough fiber powder. The asparagus rough fiber in asparagus old stem waste is obtained by alkali leaching combined with treatment of two enzyme preparations, and then the obtained asparagus rough fiber is subjected to ultramicro-pulverization, rehydration, step-by-step low-temperature treatment, steam explosion treatment, and finally hot air microwave combined drying treatment for modification. After the above operation and treatment, the water holding property and oil adsorption capacity of the asparagus rough fiber powder are significantly improved compared with those before modification, which not only effectively solves the problem of processing and utilization of asparagus old stem and other high-rough-fiber-content waste resources, but also improves the added value of the asparagus rough fiber and expands the application range thereof.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of asparagus crude fiber modification, and particularly relates to a processing method for enhancing oil and fat adsorption capacity of asparagus crude fiber powder. BACKGROUND

[0002] Asparagus, also known as Lu Shun and Shidao Bai, is a perennial herbaceous plant of Asparagaceae Asparagus (Asparagus genus), and is rich in asparagus saponin, protein, carbohydrates, dietary fiber and other nutrients, and is a high-grade vegetable with extremely comprehensive nutrients, and is also listed as a "top product" of vegetables in Shennong's Classic of Materia Medica.

[0003] However, the output rate of asparagus shoots is only 1 / 3 of asparagus stems, and most of them are old stems, although the nutrients in the old stems have good effects on improving body immunity and preventing gastrointestinal diseases, due to the lack of corresponding utilization methods and technologies, most of the old stems are directly discarded, which not only causes great waste of resources, but also pollutes the environment.

[0004] At present, in order to expand the utilization range of asparagus, asparagus is made into cans, asparagus dry, fermented beverages, or directly beaten into powder to make noodles or biscuits and other foods, but the high content of crude fiber in asparagus old stems and the poor water holding capacity and oil adsorption capacity greatly restrict the development and utilization of asparagus old stems to some extent.

[0005] In fact, natural dietary fiber is very friendly to obese people, if the crude fiber rich in asparagus can be modified to improve the water holding capacity and oil holding capacity of the crude fiber and expand its application range in some functional foods, it will not only help to improve the utilization rate of asparagus crude fiber waste, but also provide a functional fiber raw material for the food industry.

[0006] There are few studies on the modification of asparagus fiber, and some studies show that the steam explosion technology is used to treat asparagus crude fiber in a short time, which realizes the conversion of part of the insoluble dietary fiber in asparagus into soluble dietary fiber, and so far, there is no report on the technology for improving the oil adsorption capacity of asparagus crude fiber. SUMMARY

[0007] In order to solve the above technical problems, the application provides a processing method for enhancing the oil and fat adsorption capacity of asparagus crude fiber powder.

[0008] The processing method for enhancing the oil and fat adsorption capacity of asparagus crude fiber powder provided by the application comprises the following steps:

[0009] S1, crushing the old stem of asparagus and soaking it in lye, then adding cellulase and trypsin in sequence and enzymatically hydrolyzing at 50-60 DEG C for 1-2 hours, discarding the supernatant after enzyme inactivation, and obtaining asparagus crude fiber;

[0010] S2, drying the asparagus crude fiber obtained in S1 to a moisture content of less than 5%, and ultra-finely grinding to 400-600 meshes to obtain asparagus crude fiber powder;

[0011] S3, rehydrating the asparagus crude fiber powder obtained in S2 and then performing low-temperature treatment, the operation of low-temperature treatment being as follows: sealing the rehydrated asparagus crude fiber powder, first standing at 0-6 DEG C for 4-6 hours, and then placing at -20 DEG C to -16 DEG C for 1-3 days to obtain asparagus crude fiber freeze-dried powder;

[0012] S4, naturally thawing the asparagus crude fiber freeze-dried powder after low-temperature treatment in S3, treating it by steam explosion, and then drying the obtained material by hot air and microwave to a moisture content of less than or equal to 7% to obtain asparagus crude fiber powder with strong oil adsorption capacity.

[0013] The present application uses the old stem waste of asparagus, which is low in price and low in utilization rate, as the source of asparagus crude fiber powder, and uses the combination of alkali soaking and enzyme method to obtain insoluble dietary fiber in the old stem waste, and based on the fact that asparagus stems are rich in asparagus fiber, asparagus protein, asparagus acid and other components, after alkali treatment, the insoluble crude fiber in the asparagus stem can be almost completely released under the action of cellulase and trypsin in sequence, thereby improving the utilization rate of asparagus stem waste.

[0014] In addition, the obtained asparagus crude fiber is further modified by ultra-fine grinding, rehydration, low-temperature treatment, steam explosion and the like, wherein the process of ultra-fine grinding can destroy the overall structure of the crude fiber, which is beneficial to the breaking of macromolecules into small molecular fiber components; then the broken asparagus crude fiber is rehydrated, and the rehydration process is also a softening process for asparagus fiber molecules, when subjected to low-temperature treatment, these small molecules are intertwined together due to the presence of a large number of hydrogen bonds, maintaining the stability of the fiber polysaccharide, under the action of low temperature, part of the hydrogen bonds are broken, so that pores appear between the fibers, which is beneficial to loosening the dense structure and increasing the specific surface area of the powder, and finally under the action of steam explosion, the asparagus polysaccharide molecules are further broken into smaller molecules under the action of instantaneous high pressure, the particle size of the fiber powder is reduced again, and the specific surface area is further improved on the basis of the original, so that the oil adsorption capacity of the asparagus crude fiber powder can be maximized, and a high physiological activity asparagus crude fiber powder is obtained.

[0015] In the above steps, preferably, in S1, the mass-volume ratio of the asparagus old stem powder to the NaOH solution is 1 g:6-10 mL, the temperature of the alkali leaching is 50-70°C, the pH is 9.0-10.0, and the alkali leaching time is 1-3 h.

[0016] Preferably, in S1, the cellulase is added in an amount of 0.3%-5% of the weight of the asparagus old stem raw material, and the trypsin is added in an amount of 0.05-0.6% of the weight of the asparagus old stem raw material.

[0017] Preferably, in S2, the ultrafine grinding is performed by using a vibration type ultrafine grinder, and the ultrafine grinding time is 1-30 min.

[0018] Preferably, in S3, the asparagus crude fiber powder obtained in S2 is soaked in water until the rehydration amount of the asparagus crude fiber powder is 25-45% of the mass of the asparagus crude fiber powder raw material.

[0019] Preferably, in S3, the rehydration amount of the asparagus crude fiber powder is 35% of the mass of the asparagus crude fiber powder raw material.

[0020] Preferably, in S3, the rehydrated asparagus crude fiber powder is sealed and first placed under refrigeration at 4°C for 6 h, and then placed under the condition of -18°C for 1 d to obtain the asparagus crude fiber freeze-dried powder.

[0021] Preferably, in S4, in the steam explosion treatment, the ratio of the material volume to the total volume of the cavity during the treatment is 4-7:8, the steam explosion pressure is 0.8-1.8 MPa, and the pressure holding time is 40-180 s.

[0022] Preferably, in S4, in the steam explosion treatment, the ratio of the material volume to the total volume of the cavity during the treatment is 6:8, the steam explosion pressure is 0.9 MPa, and the steam pressure holding time is 90 s.

[0023] Preferably, in S4, in the hot air and microwave combined drying treatment, the material is first subjected to microwave drying and then moved to a hot air drying oven for further drying until the water content of the material is ≤7%, wherein the microwave drying power is 400-1500 W, the microwave drying time is 3-10 min, and the hot air drying temperature is 40-90°C.

[0024] Preferably, in S4, in the hot air and microwave combined drying treatment, the microwave drying power is 1000 W, the microwave drying time is 5 min, and the hot air drying temperature is 80°C.

[0025] In addition, the application of the asparagus stem waste powder prepared by the processing method to the preparation of a weight-reducing product also falls within the technical scope of the present application, and the asparagus stem waste powder accounts for 20-30% of the total weight of the weight-reducing product. The weight-reducing product includes any food or medicine containing dietary fiber and beneficial to the absorption of body fat, and specifically includes any one of a weight-reducing beverage, a biscuit, a food, a health product, and a medicine.

[0026] The present application has the following advantages:

[0027] 1. The present application effectively solves the problem of processing and utilization of high-fiber-containing fruit and vegetable resources such as asparagus stem waste, reduces environmental pollution, and turns waste into treasure to improve resource utilization;

[0028] 2. The asparagus stem waste is modified by integrated use of ultrafine grinding, rehydration, low-temperature treatment, steam explosion, and other operation techniques, which not only increases the content of soluble dietary fiber, but also significantly reduces the molecular weight of the obtained asparagus stem waste, loosens the internal structure of the asparagus stem waste, and increases the specific surface area of the powder, thereby maximizing the oil absorption capacity of the asparagus stem waste powder and developing a new use of the asparagus stem waste powder, i.e., for use in the oil absorption process in the body, thereby expanding the application range of the asparagus stem waste powder. Dietary fiber is mainly composed of various polysaccharides, and the molecular surface has many active groups, which have obvious effects on the absorption of heavy metals, toxic substances, chemical drugs, and other organic compounds. Similarly, dietary fiber also affects the absorption of fat, cholesterol, and other substances. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Water holding capacity and oil absorption capacity of asparagus stem waste powder obtained by different treatment methods;

[0030] Figure 2 Content of asparagus stem waste fiber under different extraction methods. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the present application, the present application will be further described in conjunction with specific embodiments.

[0032] Example 1

[0033] A processing method for enhancing the oil absorption capacity of asparagus stem waste powder, comprising the following steps:

[0034] S1, the asparagus old stem is crushed and then soaked in NaOH solution with pH of 9.0 at 60℃ for 3h, the mass-volume ratio of asparagus old stem powder to NaOH solution is 1g:10mL, after soaking, 3% of cellulase by weight of asparagus old stem powder is added and enzymolysis is carried out at 55℃ for 2h, after enzyme inactivation, 0.2% of trypsin by weight of asparagus old stem powder is added and enzymolysis is carried out at 50℃ for 1h, after enzyme inactivation, the supernatant is discarded, and asparagus crude fiber is obtained;

[0035] S2, the asparagus crude fiber obtained in S1 is dried to a moisture content of 2%, and is ultra-micro ground for 5min to obtain asparagus crude fiber powder;

[0036] S3, the asparagus crude fiber powder obtained in S2 is rehydrated to a rehydration amount of 35% of the raw material mass of the asparagus crude fiber powder, and then the rehydrated asparagus crude fiber powder is sealed, and is first placed at 4℃ for 5h, and then is placed at -18℃ for 1d to obtain asparagus crude fiber freeze-dried powder;

[0037] S4, the asparagus crude fiber freeze-dried powder after low-temperature treatment in S3 is naturally thawed, and after steam explosion treatment, the obtained material is dried by hot air and microwave to a water content of ≤7% to obtain asparagus crude fiber powder with strong oil adsorption capacity;

[0038] The specific operation is as follows: during steam explosion, the ratio of the volume of the material to the total volume of the cavity is 5:8, the steam explosion pressure is 0.9MPa, and the steam pressure holding time is 120s; the conditions for hot air and microwave combined drying are as follows: the material is first subjected to microwave drying treatment and then is moved to a hot air drying oven for continuous drying, and the specific conditions are as follows: the vacuum microwave drying power is 1000w, the microwave drying time is 5min, and the hot air drying temperature is 80℃, and the material is dried to a water content of less than or equal to 7%.

[0039] Example 2

[0040] A processing method for enhancing the oil adsorption capacity of asparagus crude fiber powder, the steps are as follows:

[0041] S1, the operation and conditions of S4 are the same as those in Example 1; the remaining steps are as follows:

[0042] S2, the asparagus crude fiber obtained in S1 is dried to a moisture content of 2%, and is ultra-micro ground for 8min to obtain asparagus crude fiber powder;

[0043] S3, the asparagus crude fiber powder obtained in S2 is rehydrated to a rehydration amount of 35% of the raw material mass of the asparagus crude fiber powder, and then the rehydrated asparagus crude fiber powder is sealed, and is first placed at 4℃ for 6h, and then is placed at -18℃ for 2d to obtain asparagus crude fiber freeze-dried powder.

[0044] Example 3

[0045] A processing method for enhancing the oil adsorption capacity of asparagus crude fiber powder, the steps are as follows:

[0046] The operations and conditions of S1 and S4 are the same as in Example 1; the remaining steps are as follows:

[0047] S2, the asparagus crude fiber obtained in S1 is dried to a moisture content of 2%, and is ultra-finely pulverized for 8 min to obtain asparagus crude fiber powder;

[0048] S3, the asparagus crude fiber powder obtained in S2 is rehydrated to a rehydration amount of asparagus crude fiber powder accounting for 45% of the mass of the asparagus crude fiber powder raw material, and then the rehydrated asparagus crude fiber powder is sealed and first placed under refrigeration at 0°C for 5 h, and then placed under conditions of -20°C for 1 d to obtain asparagus crude fiber lyophilized powder.

[0049] Comparative Example 1

[0050] Unlike Example 2, the asparagus crude fiber powder prepared in S1 is not subjected to any modification treatment, and is directly dried by hot air to obtain asparagus crude fiber powder.

[0051] Comparative Example 2

[0052] Unlike Example 2, the asparagus crude fiber prepared in S1 is not subjected to ultra-fine pulverization treatment, and the remaining steps are the same as in Example 2.

[0053] Comparative Example 3

[0054] Unlike Example 2, the asparagus crude fiber powder is not rehydrated or subjected to low-temperature treatment, and the asparagus crude fiber powder obtained by ultra-fine pulverization of S2 is rehydrated and then subjected to steam explosion, microwave and hot air combined drying treatment to obtain asparagus crude fiber powder.

[0055] Comparative Example 4

[0056] Unlike Example 2, the low-temperature treatment operation is as follows: the asparagus crude fiber powder obtained in S2 is rehydrated to a rehydration amount of asparagus crude fiber powder accounting for 35% of the mass of the asparagus crude fiber powder raw material, and then the rehydrated asparagus crude fiber powder is sealed and directly placed under conditions of -40°C for 2 d to obtain asparagus crude fiber lyophilized powder.

[0057] Comparative Example 5

[0058] Unlike Example 2, the low-temperature treatment operation is as follows: the asparagus crude fiber powder obtained in S2 is rehydrated to a rehydration amount of asparagus crude fiber powder accounting for 35% of the mass of the asparagus crude fiber powder raw material, and then the rehydrated asparagus crude fiber powder is sealed and directly placed under conditions of 0°C for 2 d to obtain asparagus crude fiber lyophilized powder.

[0059] Comparative Example 6

[0060] Different from Example 2, the asparagus crude fiber was first subjected to steam explosion treatment and then subjected to ultrafine grinding operation, that is, the ultrafine grinding in step S2 was replaced with steam explosion in step S4, and the rest was the same as Example 2.

[0061] Performance test of asparagus crude fiber powder in Test Example 1

[0062] 1. Water absorption test

[0063] 0.5 g of asparagus crude fiber powder was accurately weighed in a centrifuge tube, and a solution with a concentration of 20 g / L was prepared by adding purified water, and the solution was fully shaken and mixed in the centrifuge tube, and then the solution was placed in a water bath at 60°C for 30 min. After centrifugation, the volume of the supernatant was measured, and the water absorption of the asparagus crude fiber powder was calculated. The water absorption was expressed by the weight of water absorbed per gram of asparagus crude fiber powder.

[0064]

[0065] 2. Oil absorption test

[0066] 0.5 g of asparagus crude fiber powder was accurately weighed in a centrifuge tube, and then 10 g of first grade salad oil was added, and mixed for 30 min, and then centrifuged, and after standing for 10 min, the volume of the supernatant salad oil was measured, and the oil absorption of the asparagus crude fiber powder was calculated. The oil absorption was expressed by the mass of oil absorbed per gram of asparagus crude fiber powder.

[0067]

[0068] The water holding capacity and oil absorption of the asparagus crude fiber powder prepared in Examples 1-3 and Comparative Examples 1-6 of the present application are shown in Table 1 and FIG. 1, respectively. Figure 1

[0069] Table 1 Water holding capacity and oil absorption of products

[0070]

[0071] From the data in the table, it can be seen that in Comparative Example 1, the water holding capacity and oil absorption of the asparagus crude fiber powder obtained by the conventional method are poor.

[0072] ​In Comparative Examples 2-6, the water holding capacity and oil absorption of the asparagus crude fiber powder prepared after the asparagus crude fiber powder was modified in different ways were improved compared to Comparative Example 1, which indicated that ultrafine grinding, steam explosion and other operations were beneficial to the improvement of the oil absorption and other properties of the asparagus crude fiber powder. In addition, appropriate low-temperature treatment operation could also adjust the water holding capacity and oil absorption of the asparagus crude fiber powder. However, if the asparagus crude fiber powder was directly treated at an extremely low temperature, the pore size of the fiber might be severely broken due to the lack of step-by-step temperature reduction operation, which might not be conducive to the increase of the specific surface area of the fiber powder, and the oil absorption performance of the crude fiber powder might be reduced.

[0073] In Examples 1-3, the asparagus crude fiber was subjected to step-by-step low-temperature treatment, followed by steam explosion, microwave combined with hot air drying and other operations, and the oil absorption of the asparagus crude fiber powder obtained was about three times that of Comparative Example 1. The reason for this phenomenon might be that the step-by-step low-temperature operation was beneficial to the formation of the pore size track of asparagus crude fiber polysaccharide, and the excessive low temperature did not cause the breaking of most hydrogen bonds, which was beneficial to the formation of the dense pore size of the asparagus crude fiber polysaccharide, thereby improving the specific surface area and the oil absorption effect.

[0074] In addition, the content of the asparagus crude fiber obtained by different extraction methods was also explored to obtain the optimal extraction conditions of the asparagus crude fiber.

[0075] Example 4

[0076] The asparagus crude fiber was extracted by the following method, and the specific operation was as follows:

[0077] The asparagus old stem was crushed and then soaked in a NaOH solution with a pH of 10.0 at 70℃ for 2h, and the mass-volume ratio of the asparagus old stem powder to the NaOH solution was 1g:8mL. After soaking, 1% of cellulase based on the weight of the asparagus old stem powder was added for enzymatic hydrolysis at 55℃ for 2h. After enzyme inactivation, 0.05% of trypsin based on the weight of the asparagus old stem powder was added for enzymatic hydrolysis at 50℃ for 1h. After enzyme inactivation, the supernatant was discarded to obtain the asparagus crude fiber.

[0078] Example 5

[0079] The asparagus crude fiber was extracted by the following method, and the specific operation was as follows:

[0080] The asparagus old stem was crushed and then soaked in a NaOH solution with a pH of 9.0 at 60℃ for 3h, and the mass-volume ratio of the asparagus old stem powder to the NaOH solution was 1g:10mL. After soaking, 3% of cellulase based on the weight of the asparagus old stem powder was added for enzymatic hydrolysis at 55℃ for 2h. After enzyme inactivation, the supernatant was discarded to obtain the asparagus crude fiber.

[0081] Example 6

[0082] The asparagus crude fiber is extracted according to the following method, and the specific operation is as follows:

[0083] The asparagus old stem is crushed and soaked in NaOH solution with pH of 9.0 at 60℃ for 3h, the mass-volume ratio of asparagus old stem powder and NaOH solution is 1g:10mL, then 0.6% of trypsin by weight of asparagus old stem powder is added and enzymolysis is carried out at 60℃ for 2h, after enzyme inactivation, the supernatant is discarded, and the asparagus crude fiber is obtained.

[0084] The content of the asparagus crude fiber obtained by different preparation methods is shown in Table 2 and the attached Figure 2 .

[0085] Table 2 Content of asparagus crude fiber obtained by different preparation methods (%)

[0086] Experimental group Example 1 Example 4 Example 5 Example 6 Content of crude fiber of asparagus (%) 66.51 53.29 50.03 36.30

[0087] The data in the table shows that in Example 1 and Example 4, both of which use alkali method + enzyme method treatment, and the enzyme preparation is two, including cellulase and trypsin, after the treatment, the content of the asparagus crude fiber prepared is much higher than the fiber content obtained by using only one kind of enzyme preparation, in other words, the treatment of asparagus stem by cellulase and trypsin is beneficial to the better release of polysaccharide components wrapped by protein, cellulose and other components in the stem, thereby improving the release amount of dietary fiber.

Claims

1. A processing method for enhancing the oil adsorption capacity of asparagus stem fiber powder, characterized in that, Comprising the following steps: S1, after crushing asparagus old stem, it is placed in NaOH solution with pH 9.0 and soaked at 60 DEG C for 3h, the mass volume ratio of asparagus old stem powder and NaOH solution is 1g:10ml, then 3% of cellulase by weight of asparagus old stem powder is added in turn and enzymolysis at 55 DEG C for 2h, after enzyme inactivation, 0.2% of trypsin by weight of asparagus old stem powder is added and enzymolysis at 50 DEG C for 1h, after enzyme inactivation, the supernatant is discarded, and asparagus crude fiber is obtained; S2, the asparagus crude fiber obtained in S1 is dried to a moisture content of less than 5%, and is ultra-finely pulverized to 400-600 meshes to obtain asparagus crude fiber powder; S3, the asparagus crude fiber powder obtained in S2 is rehydrated and then subjected to low temperature treatment, specifically: the asparagus crude fiber powder obtained in S2 is rehydrated to a rehydration amount of 35%-45% of the original mass of the asparagus crude fiber powder, then the rehydrated asparagus crude fiber powder is sealed, and is first placed at 4 DEG C for 6h, and then is placed at-18 DEG C for 2d to obtain asparagus crude fiber freeze-dried powder; S4, the asparagus crude fiber freeze-dried powder after low temperature treatment in S3 is naturally thawed, and after steam explosion treatment, the obtained material is dried by hot air and microwave to a moisture content of ≤7% to obtain asparagus crude fiber powder with strong oil adsorption capacity, wherein, during steam explosion, the ratio of material volume to total cavity volume is 5:8, the steam explosion pressure is 0.9MPa, and the steam pressure holding time is 120s; the conditions for hot air and microwave combined drying are as follows: the material is first subjected to microwave drying treatment and then is moved to a hot air drying oven for continuous drying, and the specific conditions are as follows: the vacuum microwave drying power is 1000w, the microwave drying time is 5min, the hot air drying temperature is 80 DEG C, and the material is dried to a moisture content of ≤7%.

2. Use of the asparagus rough fiber powder prepared according to the processing method of claim 1 in the preparation of a slimming product, characterized in that, The asparagus crude fiber powder accounts for 20-30% of the total weight of the weight loss product.

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