阅读说明：本技术 一种甘薯淀粉生产排放水中有益物质回收工艺 (Process for recovering beneficial substances in discharged water in sweet potato starch production ) 是由 单守水 张毅 刘苹 于飞 隋彩伟 于 2021-02-25 设计创作，主要内容包括：一种甘薯淀粉生产排放水中有益物质回收工艺,根据甘薯淀粉排放水中成分分析,采用生物分离技术,获得排放水中的不同的生物活性物质或营养成分,如甘薯蛋白、低糖含量甘薯汁、甘薯蛋白肽等高附加值的产品,从而使排放水得到综合利用,降低生产用水量,降低生产成本。本发明采用过滤、超滤、浓缩获得高附加值的甘薯蛋白肽及低热量低糖含量的浓缩甘薯汁,富含各种氨基酸、矿物质及多种非淀粉多糖等生物活性物质,可广泛应用于发酵、保健食品、功能性饮料等食品工业中；最终反渗透水回收循环利用于生产,极大程度减少了排放水的处理工序并避免了资源的浪费。本发明降低处理排放水的成本并将排放水进行了资源再利用,降低生产成本,增加了利润点。(A process for recovering the useful substances from the water discharged from the production of sweet potato starch features that the different bioactive substances or nutritive components in the water, such as sweet potato protein, low-sugar sweet potato juice, sweet potato protein peptide, etc, are obtained by bioseparation technique according to the analysis of components in the water. The invention adopts filtration, ultrafiltration and concentration to obtain the sweet potato protein peptide with high added value and the concentrated sweet potato juice with low calorie and low sugar content, is rich in various amino acids, mineral substances, various non-starch polysaccharides and other bioactive substances, and can be widely applied to food industries such as fermentation, health food, functional beverage and the like; finally, the reverse osmosis water is recycled for production, so that the treatment process of the discharged water is greatly reduced, and the waste of resources is avoided. The invention reduces the cost of treating the discharged water, recycles the resources of the discharged water, reduces the production cost and increases the profit.)

1. A process for recovering beneficial substances in water discharged in sweet potato starch production is characterized by comprising the following steps:

(1) solid-liquid separation of discharged water:

(11) primary plate and frame filtration: adding 5-10% of diatomite of a first specification and 0.3-1% of diatomite of a second specification into the discharged water of sweet potato starch production, mixing, uniformly stirring, and performing plate-frame filtration to obtain a plate-frame liquid of primary clarification;

(12) and (3) ultrafiltration: carrying out ultrafiltration concentration on the plate-and-frame liquid subjected to primary clarification by using an ultrafiltration membrane with the molecular weight of 50000-60000 to obtain an ultrafiltration concentrated solution and a primary filter cake;

(2) preparation of sweet potato protein peptide:

(21) adding water into the primary filter cake obtained in the step (12) for redissolving, uniformly stirring under the condition that the pH value is 4.0-4.5, adding 0.5-1% of non-starch polysaccharide hydrolase according to the dry matter content of the feed liquid, carrying out enzymolysis at 45-55 ℃ for 2-4h, and then heating the feed liquid for inactivating enzyme;

(22) secondary filtration: performing plate-frame filtration on the feed liquid subjected to enzyme deactivation in the step (21) to obtain a secondary clarified plate-frame liquid and a secondary filter cake, concentrating the secondary clarified plate-frame liquid to prepare sweet potato concentrated juice, and using the secondary filter cake for enzymolysis;

(23) and (3) proteolysis: mixing the secondary filter cake obtained in the step (22) with water for redissolution, adjusting the pH value to 8.0-8.5 by using sodium hydroxide, adding 1-2% of alkaline protease and neutral protease according to the protein content, carrying out enzymolysis for 4-6h at 45-60 ℃, and then heating the feed liquid for enzyme deactivation;

(24) and (3) filtering for three times: performing plate-frame filtration on the feed liquid subjected to enzyme deactivation in the step (23) to obtain three-time clarified plate-frame liquid and three-time filter cakes;

(25) decoloring and desalting: adding 0.5-1% of activated carbon into the plate-frame liquid clarified for the third time for decolorization, and performing nanofiltration and desalination treatment on the filtrate obtained by filtration by using a 200-500nm membrane;

(26) concentration: carrying out vacuum concentration on the decolorized and desalted feed liquid to obtain feed liquid with 10% -15% of dry matter;

(27) and (3) drying: and (4) carrying out spray drying on the feed liquid concentrated in the step (26) to obtain high-purity protein peptide powder.

2. The process for recovering beneficial substances in discharged water of sweet potato starch production according to claim 1, further comprising (3) preparation of low-calorie sweet potato concentrated juice:

(31) carrying out reverse osmosis treatment on the ultrafiltration concentrated solution obtained in the step (22) to obtain sweet potato concentrated juice with dry matter of more than 35%, and recycling the permeate obtained by reverse osmosis as feeding water for production;

(32) the sweet potato concentrated juice with the concentration of more than 35 percent is subjected to vacuum concentration to obtain the sweet potato high concentrated juice with the concentration of more than 70 percent, and the evaporated water is directly recycled for production.

3. The process for recovering beneficial substances in water discharged from sweet potato starch production according to claim 1, wherein in the step (11), the first specification diatomite is 300 meshes, and the second specification diatomite is 10 meshes.

4. The process for recovering beneficial substances in effluent from sweet potato starch production as claimed in claim 1, wherein in step (12), the primary clarified plate-and-frame liquid is subjected to ultrafiltration concentration by using an ultrafiltration membrane with molecular weight of 50000-.

5. The process for recovering beneficial substances in water discharged in the production of sweet potato starch as claimed in claim 1, wherein in the steps (21) and (23), the feed liquid is heated to 80 ℃ to inactivate enzyme for 10 min.

6. The process for recovering beneficial substances in water discharged in sweet potato starch production according to claim 1, wherein in the step (25), 0.5-1% of activated carbon is added into the plate-and-frame liquid clarified for three times for decolorization at 50 ℃;

in the step (25), the permeate liquid after nanofiltration desalination is directly recycled as feeding water for production.

7. The process for recovering beneficial substances in discharged water in sweet potato starch production according to claim 1, wherein the primary filter cake, the secondary filter cake and the tertiary filter cake are sold as auxiliary materials for preparing fermented feed or fertilizer.

Technical Field

The invention belongs to the technical field of sweet potato starch production, and particularly relates to a process for recovering beneficial substances in discharge water of sweet potato starch production.

Background

At present, sweet potato starch is mainly produced by taking sweet potatoes as raw materials, crushing the sweet potatoes, mixing the crushed sweet potatoes with water for precipitation to obtain starch, discharging the rest water, discharging 15t of water when 1t of starch is produced, and discharging a large amount of water. The starch discharge water has high COD, high suspended matter concentration and high organic matter content, and is easy to be infected with bacteria, acidified and corrupted due to rich nutrient substances in water, and can enter a sewage treatment tank for treatment only through complex treatment, so the alkali consumption in the process is high, and the treatment process has high cost.

The sweet potatoes are agricultural products, discharged water after starch removal contains various other nutrient substances except starch, such as sugar, protein, inorganic salt and various bioactive substances, and if the sweet potatoes are completely discharged, the waste of resources is also caused. The starch discharge water treatment is a problem which is difficult to solve by starch manufacturers at present, and the waste water causes serious pollution and harm to the environment and farmlands. A technical scheme for recovering beneficial substances in the discharged water in the production of sweet potato starch is needed urgently.

Disclosure of Invention

Therefore, the invention provides a process for recovering beneficial substances in sweet potato starch production discharge water, and solves the problems of resource waste and environmental pollution caused by direct discharge of the sweet potato starch production discharge water.

In order to achieve the above purpose, the invention provides the following technical scheme: a process for recovering beneficial substances in discharged water in sweet potato starch production comprises the following steps:

(1) solid-liquid separation of discharged water:

(11) primary plate and frame filtration: adding 5-10% of diatomite of a first specification and 0.3-1% of diatomite of a second specification into the discharged water of sweet potato starch production, mixing, uniformly stirring, and performing plate-frame filtration to obtain a plate-frame liquid of primary clarification;

(12) and (3) ultrafiltration: carrying out ultrafiltration concentration on the plate-and-frame liquid subjected to primary clarification by using an ultrafiltration membrane with the molecular weight of 50000-60000 to obtain an ultrafiltration concentrated solution and a primary filter cake;

(2) preparation of sweet potato protein peptide:

(21) adding water into the primary filter cake obtained in the step (12) for redissolving, uniformly stirring under the condition that the pH value is 4.0-4.5, adding 0.5-1% of non-starch polysaccharide hydrolase according to the dry matter content of the feed liquid, carrying out enzymolysis at 45-55 ℃ for 2-4h, and then heating the feed liquid for inactivating enzyme;

(22) secondary filtration: performing plate-frame filtration on the feed liquid subjected to enzyme deactivation in the step (21) to obtain a secondary clarified plate-frame liquid and a secondary filter cake, concentrating the secondary clarified plate-frame liquid to prepare sweet potato concentrated juice, and using the secondary filter cake for enzymolysis;

(23) and (3) proteolysis: mixing the secondary filter cake obtained in the step (22) with water for redissolution, adjusting the pH value to 8.0-8.5 by using sodium hydroxide, adding 1-2% of alkaline protease and neutral protease according to the protein content, carrying out enzymolysis for 4-6h at 45-60 ℃, and then heating the feed liquid for enzyme deactivation;

(24) and (3) filtering for three times: performing plate-frame filtration on the feed liquid subjected to enzyme deactivation in the step (23) to obtain three-time clarified plate-frame liquid and three-time filter cakes;

(25) decoloring and desalting: adding 0.5-1% of activated carbon into the plate-frame liquid clarified for the third time for decolorization, and performing nanofiltration and desalination treatment on the filtrate obtained by filtration by using a 200-500nm membrane;

(26) concentration: carrying out vacuum concentration on the decolorized and desalted feed liquid to obtain feed liquid with 10% -15% of dry matter;

(27) and (3) drying: and (4) carrying out spray drying on the feed liquid concentrated in the step (26) to obtain high-purity protein peptide powder.

The preferable scheme of the process for recovering the beneficial substances in the discharge water of the sweet potato starch production also comprises (3) the preparation of low-calorie sweet potato concentrated juice:

(31) carrying out reverse osmosis treatment on the ultrafiltration concentrated solution obtained in the step (22) to obtain sweet potato concentrated juice with dry matter of more than 35%, and recycling the permeate obtained by reverse osmosis as feeding water for production;

(32) the sweet potato concentrated juice with the concentration of more than 35 percent is subjected to vacuum concentration to obtain the sweet potato high concentrated juice with the concentration of more than 70 percent, and the evaporated water is directly recycled for production.

As a preferable scheme of the process for recovering the beneficial substances in the discharge water of the sweet potato starch production, in the step (11), the first specification diatomite is 300 meshes, and the second specification diatomite is 10 meshes.

As a preferred scheme of the process for recovering beneficial substances in the sweet potato starch production discharge water, in the step (12), the plate-and-frame liquid which is clarified for the first time is subjected to ultrafiltration concentration by using an ultrafiltration membrane with the molecular weight of 50000-60000 to obtain an ultrafiltration concentrated solution which is concentrated by 20 times.

As a preferred scheme of the recovery process of beneficial substances in the discharged water in sweet potato starch production, in the step (21) and the step (23), the feed liquid is heated to 80 ℃ to inactivate enzyme for 10 min.

As a preferred scheme of the recovery process of beneficial substances in the discharged water of sweet potato starch production, in the step (25), 0.5 to 1 percent of activated carbon is added into the plate-frame liquid clarified for three times for decolorization at 50 ℃;

in the step (25), the permeate liquid after nanofiltration desalination is directly recycled as feeding water for production.

As the optimal scheme of the recovery process of beneficial substances in the discharged water in the production of sweet potato starch, the primary filter cake, the secondary filter cake and the tertiary filter cake are sold as auxiliary materials for preparing fermented feed or fertilizer.

According to the invention, different bioactive substances or nutritional ingredients in the discharged water, such as high-added-value products of sweet potato protein, low-sugar content sweet potato juice, sweet potato protein peptide and the like, are obtained by selecting a proper bioseparation technology according to the component analysis of the sweet potato starch discharged water, so that the discharged water is comprehensively utilized, the water consumption for production is reduced, and the production cost is reduced. The invention adopts filtration, ultrafiltration and concentration to obtain the sweet potato protein peptide with high added value and the concentrated sweet potato juice with low calorie and low sugar content, is rich in various amino acids, mineral substances, various non-starch polysaccharides and other bioactive substances, and can be widely applied to food industries such as fermentation, health food, functional beverage and the like; the final reverse osmosis water can be recycled for production, thereby greatly reducing the treatment process of the discharged water and avoiding the waste of resources. The invention reduces the cost of treating the discharged water, recycles the resources of the discharged water, reduces the production cost and increases the profit.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention provides a process for recovering beneficial substances in discharged water in sweet potato starch production, which comprises the following steps:

(1) solid-liquid separation of discharged water:

(11) primary plate and frame filtration: adding 5-10% of 300-mesh diatomite and 0.3-1% of 10-mesh diatomite into the sweet potato starch production discharge water, mixing, uniformly stirring, and performing plate-frame filtration to obtain a primarily clarified plate-frame liquid;

(12) and (3) ultrafiltration: carrying out ultrafiltration concentration on the plate-and-frame liquid subjected to primary clarification by using an ultrafiltration membrane with the molecular weight of 50000-60000 to obtain ultrafiltration concentrated liquid of 40 times and a primary filter cake;

(2) preparation of sweet potato protein peptide:

(21) adding water into the primary filter cake obtained in the step (12) for redissolving, uniformly stirring under the condition that the pH value is 4.0-4.5, adding 0.5-1% of non-starch polysaccharide hydrolase according to the dry matter content of the feed liquid, carrying out enzymolysis at 45-55 ℃ for 2-4h, and then heating the feed liquid to 80 ℃ for inactivating enzyme for 10 min;

(22) secondary filtration: performing plate-frame filtration on the feed liquid subjected to enzyme deactivation in the step (21) to obtain a secondary clarified plate-frame liquid and a secondary filter cake, concentrating the secondary clarified plate-frame liquid to prepare sweet potato concentrated juice, and using the secondary filter cake for enzymolysis;

(23) and (3) proteolysis: mixing the secondary filter cake obtained in the step (22) with water for redissolution, adjusting the pH value to 8.0-8.5 by using sodium hydroxide, adding 1-2% of alkaline protease and neutral protease according to the protein content, carrying out enzymolysis for 4-6h at 45-60 ℃, and then heating the feed liquid to 80 ℃ for enzyme deactivation for 10 min;

(24) and (3) filtering for three times: performing plate-frame filtration on the feed liquid subjected to enzyme deactivation in the step (23) to obtain three-time clarified plate-frame liquid and three-time filter cakes;

(25) decoloring and desalting: adding 0.5-1% of activated carbon into the three-time clarified plate-and-frame liquid, decoloring at 50 ℃, carrying out nanofiltration desalination on the filtrate obtained by filtration by using a 200-plus-500 nm membrane, and directly recovering the permeate obtained by the nanofiltration desalination as feed water for production;

(26) concentration: carrying out vacuum concentration on the decolorized and desalted feed liquid to obtain feed liquid with 10% -15% of dry matter;

(27) and (3) drying: and (4) carrying out spray drying on the feed liquid concentrated in the step (26) to obtain high-purity protein peptide powder.

In this embodiment, the method further comprises (3) preparing the low-calorie sweet potato concentrated juice:

(31) carrying out reverse osmosis treatment on the ultrafiltration concentrated solution obtained in the step (22) to obtain sweet potato concentrated juice with dry matter of more than 35%, and recycling the permeate obtained by reverse osmosis as feeding water for production;

(32) the sweet potato concentrated juice with the concentration of more than 35 percent is subjected to vacuum concentration to obtain the sweet potato high concentrated juice with the concentration of more than 70 percent, and the evaporated water is directly recycled for production.

In one embodiment of the process for recovering beneficial substances in the discharge water of sweet potato starch production, the primary filter cake, the secondary filter cake and the tertiary filter cake are sold as auxiliary materials for preparing fermented feed or fertilizer.

Specifically, in the step (12), indexes of protein concentrated solution obtained by filtering sweet potato starch discharge water by a plate frame and then performing ultrafiltration are shown in table 1:

TABLE 1 protein concentrate index

	Feed liquid	Volume/m3	Solids content/%)	Protein content/%)
					1	Sweet potato drainage	10	3	1.6
2	Ultrafiltered concentrated solution	0.5	20	17
					3	Solid protein product			88

The protein concentrated solution is gray green in appearance and is viscous liquid, and the product is subjected to spray drying to obtain a solid powdery product.

Specifically, the pH change of the feed liquid in the enzymolysis process in step (23) is shown in table 2:

TABLE 2 feed solution pH Change during enzymolysis

Indexes of the filtrate obtained after enzymolysis and 150nm nanofiltration desalination in the step (23) are shown in the table 3:

TABLE 3 index of the filtrate after enzymolysis

	Feed liquid	Mass/g	Solids content/%)	Protein content/%)	Protein distribution/%	Protein purity/%)
							1	Sweet potato drainage	1800	5	2.16	100	43.2
2	Ultrafiltered concentrated solution	860	7	3.2	70.7	45.7
							3	Ultrafiltrate	2082	1	0.41	32.51	41

Specifically, protease is added for enzymolysis, the molecular weight of protein peptide is within 5000Da, and the protein purity reaches 86% after nanofiltration.

Specifically, the low-calorie sweet potato concentrated juice obtained in the step (3) and the permeate with 2% of dry matter are concentrated by reverse osmosis, and are added by 10m³The feed liquid is concentrated to 6% dry matter in the first stage, enters the second stage for reverse osmosis, is concentrated to 25%, is used for 4h, and then 400kg of concentrated solution is discharged with the average speed of 2.4m³And/h, concentrating the mixture by a triple-effect evaporator until the dry matter is 70 percent, and obtaining the indexes of the finished product, which are shown in a table 4:

TABLE 4 index of the final product obtained by concentration of the triple effect evaporator to 70% dry matter

Specifically, all nutrient components such as polyphenol and the like can be recovered by reverse osmosis, and a refrigeration system is arranged to reduce the deterioration risk of feed liquid, reduce the energy consumption of evaporation and concentration and accelerate the processing speed.

According to the invention, different bioactive substances or nutritional ingredients in the discharged water, such as high-added-value products of sweet potato protein, low-sugar content sweet potato juice, sweet potato protein peptide and the like, are obtained by selecting a proper bioseparation technology according to the component analysis of the sweet potato starch discharged water, so that the discharged water is comprehensively utilized, the water consumption for production is reduced, and the production cost is reduced. The invention adopts filtration, ultrafiltration and concentration to obtain the sweet potato protein peptide with high added value and the concentrated sweet potato juice with low calorie and low sugar content, is rich in various amino acids, mineral substances, various non-starch polysaccharides and other bioactive substances, and can be widely applied to food industries such as fermentation, health food, functional beverage and the like; the final reverse osmosis water can be recycled for production, thereby greatly reducing the treatment process of the discharged water and avoiding the waste of resources. The invention reduces the cost of treating the discharged water, recycles the resources of the discharged water, reduces the production cost and increases the profit.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.