CN107183312B - Method for promoting drying and dehydration of potato pulp and application thereof - Google Patents

Abstract

The invention discloses a method for promoting drying and dehydration of potato residues and an application thereof, belonging to the field of biomass resource utilization. In the present invention, fresh potato residue is used as fermentation substrate, at least one of pectinase, cellulase and hemicellulase is added to carry out enzymolysis treatment, and mixed bacterial liquid of Lactobacillus plantarum and yeast is inoculated, and solid-state anaerobic fermentation is carried out. , can effectively prevent the potato dregs from spoilage, improve the nutritional value of the potato dregs, and make the potato dregs quickly dehydrate, easy to dry, and have good economic and environmental benefits.

Description

A kind of method and application of promoting drying and dehydration of potato residue

technical field

The invention relates to a method for promoting drying and dehydration of potato residues and application thereof, and belongs to the field of biomass resource utilization.

Background technique

China's potato planting area and total output ranks first in the world, and a large amount of potato is used for starch and whole flour processing every year. In the process of producing potato starch, a large amount of waste potato dregs is produced, and about 6-7 tons of potato dregs are produced for every 1 ton of potato starch produced on average. With the rapid development of potato starch industry, the problem that potato residue cannot be well utilized has become a bottleneck problem restricting the development of potato starch processing industry.

Potato residue is mainly composed of water, cell debris and residual starch granules. The water content of fresh potato dregs can reach 90%, and there are also substances with strong water holding capacity such as cellulose, hemicellulose and pectin, which make the potato dregs not easy to dry, and the drying cost is high, and the potato dregs come with 33 kinds of bacteria: 28 kinds of bacteria, 4 kinds of molds, and 1 kind of yeast make potato dregs difficult to store and transport, easy to spoil, and produce bad smell. The transformation, utilization and efficiency improvement of potato residues cannot be solved, and it is easy to accumulate corruption, cause environmental problems, and bring trouble and losses to enterprises. The daily output of potato dregs is huge. At present, the research on potato dregs is still in small batch experimental research, and it is still impossible to solve the accumulation and corruption of potato dregs caused by anti-corrosion and rapid dehydration and drying. The growth of spoilage bacteria in the dregs, reducing the water holding capacity of potato dregs, realizing rapid dehydration of potato dregs, reducing drying costs and improving the nutritional value of potato dregs have become an urgent problem to be solved.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for inhibiting the growth of miscellaneous bacteria in potato dregs, improving the quality of potato dregs and realizing rapid dehydration and drying, which can effectively prevent potato dregs from spoilage, improve the nutritional value of potato dregs, and make potato dregs Rapid dehydration, easy drying, and good economic and environmental benefits.

The first object of the present invention is to provide a fermentation method of potato pomace, which uses fresh potato pomace as a fermentation substrate and adds at least one of pectinase, cellulase and hemicellulase to carry out enzymatic hydrolysis Treatment, and inoculated with Lactobacillus plantarum and yeast mixed bacterial liquid, solid-state anaerobic fermentation.

In an embodiment of the present invention, the fresh potato residue has a moisture content of 85-95%.

In one embodiment of the present invention, the enzymatic hydrolysis treatment is performed by mixing pectinase and cellulase in a ratio of 1-3:1-10, and adding pectinase in an amount of 0.25-13 U/g in fresh potato residue.

In one embodiment of the present invention, the enzymatic hydrolysis treatment is performed by mixing pectinase and hemicellulase in a ratio of 1-3:1-5, and adding pectinase in an amount of 0.25-13 U/g Add to fresh potato pulp.

In an embodiment of the present invention, the enzymatic hydrolysis treatment is performed by mixing pectinase: cellulase: hemicellulase in a ratio of 1 to 3: 1 to 10: 1 to 5, and pectinase to The addition amount of 0.25～13U/g is added to the fresh potato residue

In an embodiment of the present invention, the solid-state anaerobic fermentation is followed by mechanical dehydration and drying.

In one embodiment of the present invention, the inoculation is to inoculate a mixed bacterial solution of Lactobacillus plantarum and yeast with an inoculum amount of 2-14% (volume of bacterial solution mL/mass of fermentation substrate g), and the mixed bacterial solution is The concentration of the solution was (1.0～9.9)×10 ⁹ CFU/mL.

In an embodiment of the present invention, the mixing ratio of Lactobacillus plantarum and yeast in the mixed bacterial solution is 1-4:1-5

In one embodiment of the present invention, the method performs mechanical stirring and mixing after adding the enzyme liquid or bacterial liquid, or adopts

Evenly spray the mixture of enzyme and bacterial strains and then lay them up in layers.

In an embodiment of the present invention, the fermentation adopts a device such as a sealed bag, a pit stacking seal, or a closed fermenter to achieve anaerobic or anaerobic conditions.

In an embodiment of the present invention, the fermentation temperature is 25-39° C., and the fermentation time is 48-120 h.

In an embodiment of the present invention, the dehydration method is plate and frame filter press, screw extrusion, centrifugal dehydration or a combination thereof.

In one embodiment of the present invention, the drying method is forced air drying, air flow drying, circulation drying, flash drying or a combination thereof.

In one embodiment of the present invention, the method specifically includes the following steps:

(1) Using fresh potato residue as the fermentation substrate, adjusting the moisture content to 85-95%,

(2) Mix pectinase or the mixed enzyme of pectinase, cellulase and hemicellulase with the fermentation substrate, the enzyme addition amount is 0.25-13U/g, and the mixing ratio is (pectinase) 1-3 : (Cellulase) 1-10: (Hemicellulase) 1-5, inoculate Lactobacillus plantarum or Lactobacillus plantarum mixed bacterial liquid with highly active yeast after mechanical stirring or stirring to make it evenly mixed, the amount of bacterial liquid inoculum It is 2-14% (bacteria liquid volume mL/fermentation substrate mass g), and the mixed bacterial liquid ratio is (Lactobacillus plantarum) 1-4: (highly active yeast) 1-5. Mechanical stirring or turning to make it evenly mixed, sealing bags and pits to seal or airtight fermenters to achieve anaerobic or anaerobic conditions, and solid-state anaerobic fermentation at 25-39 °C for 48-120 hours.

(3) After the fermentation is completed, the dehydration of potato residue is realized by means of plate and frame filter press, screw extrusion and centrifugation.

(4) After dehydration, use blast drying, air drying, circulation drying, flash drying or a combination thereof to dry the potato dregs.

Beneficial effects: (1) In the present invention, anaerobic fermentation is carried out by inoculating mixed microorganisms, combined with enzymatic treatment of potato residues, with pectinase as the main ingredient and cellulose or hemicellulose as a supplement, so as to provide suitable enzymes for enzymatic hydrolysis during the growth of microorganisms. pH, and the products of enzymatic hydrolysis provide a nutrient source for the growth of bacteria, so that the two can play a synergistic role with each other, and improve the fermentation level of fresh potato residue without adding additional nutrients. The metabolites of the bacteria enrich the nutritional composition of potato residues, improve the application value of potato residues as feed, and at the same time enhance the ability to inhibit spoilage, and release the water bound by potato residues to a large extent, realizing rapid dehydration of potato residues And efficient drying, the moisture content is less than 30% after drying for 120min, and the moisture content is less than 10% after drying for 240min. Compared with the extraction of effective components and silage from potato residues, the cost advantage is obvious, and it can better adapt to the current situation and needs of comprehensive utilization of potato residues in my country.

(2) The method of the present invention uses fresh potato dregs as a fermentation substrate, and can directly process potato dregs. Compared with other raw material fermentation processes such as mixed wheat bran and rice bran, the pretreatment cost and the processing difficulty are greatly reduced, and the cost of The yield of potato residues treated by the method of the invention is increased by 1.38-1.88 times.

(3) The present invention adopts enzyme-combined strain fermentation to synergize enzymes and microorganisms, improve fermentation level, and bacterial strain metabolites are beneficial to enrich the nutritional composition of potato dregs and inhibit potato spoilage, and can also greatly reduce the amount of fresh potato dregs. Viscosity, enhance its dehydration ability, reduce its processing difficulty and achieve its rapid drying.

(4) The solid-state anaerobic fermentation of the present invention can obviously improve the fermentation effect of potato dregs as a culture medium, shorten the fermentation period (60h has a higher fermentation level), improve the nutritional value of potato dregs, and the bacterial species are rich and beneficial The metabolites of organic acids, single-cell protein, etc. increase the advantages of potato residues used in feed. The organic acid content (especially lactic acid) in the fermented potato residue is significantly higher than that of the untreated potato residue. The lactic acid content increases from 0.0012mg/g to 4.787mg/g, and the crude protein content increases by 42%, which is significantly richer. Potato dregs as a nutritional component of feed.

Description of drawings

Fig. 1 is the mildew condition of the fresh potato dregs after being placed at room temperature for five days with enzyme method combined with bacterial strain fermentation treatment, uninoculated fermentation treatment and without any treatment; A, control; B, potato dregs after inoculation with microorganisms;

Figure 2 shows the relationship between the moisture content and drying time of potato residues in different treatments; A is the addition of pectinase of 0.25U/g, inoculated with 4% Lactobacillus plantarum; B is only inoculated with 4% Lactobacillus plantarum; C is without Potato dregs of any treatment; D is the addition amount of pectinase 3.75U/g, the enzyme activity ratio of pectinase:cellulase is 1:1, inoculated with 4% Lactobacillus plantarum; E is the addition amount of pectinase is 0.25 U/g, the enzyme activity ratio of pectinase: cellulase: hemicellulase is 1:2:3, inoculated with 4% Lactobacillus plantarum; F is the addition amount of pectinase is 0.25U/g, pectinase , the enzyme activity ratio of cellulase is 1:4; G is potato starch; H is microcrystalline cellulose;

Figure 3 shows the relationship between the drying rate and moisture content of potato residues in different treatments; A is the amount of pectinase added is 0.25U/g, inoculated with 4% Lactobacillus plantarum; B is only inoculated with 4% Lactobacillus plantarum; C is without Potato dregs of any treatment; D is the addition amount of pectinase 3.75U/g, the enzyme activity ratio of pectinase:cellulase is 1:1, inoculated with 4% Lactobacillus plantarum; E is the addition amount of pectinase is 0.25 U/g, the enzyme activity ratio of pectinase: cellulase: hemicellulase is 1:2:3, inoculated with 4% Lactobacillus plantarum; F is the addition amount of pectinase is 0.25U/g, pectinase , The enzyme activity ratio of cellulase is 1:4; G is potato starch; H is microcrystalline cellulose.

Detailed ways

The Lactobacillus plantarum in the specific embodiment is Lactobacillus plantarum CCTCC M 2017138 or Lactobacillus plantarum CCFM8661 (published in the national invention patent with publication number CN102586148A), and the yeast is commercialized Angel soy sauce yeast (Saccharomyces ruckeri).

Example 1

Add the pectinase of 1U/g to the fresh potato residue, and inoculate the bacterial liquid of Lactobacillus plantarum CCTCC M 2017138 that the bacterial liquid concentration is 5.6×10 ⁹ CFU/mL, and the inoculation amount is 10% (the bacterial liquid volume mL/fermentation bottom). Material amount g), after mixing evenly, solid-state anaerobic fermentation was carried out at 37°C for 72h. After the fermentation, centrifuge dehydration, the total number of colonies in the fermentation system was determined, and a certain amount of potato residue was taken out to observe the mildew condition at room temperature. Using fresh potato residue as a control, it was cultured under the same conditions (solid-state anaerobic fermentation at 37°C for 72h).

As shown in Table 1, the addition of pectinase and Lactobacillus plantarum fermentation treatment can significantly reduce the total number of colonies in the fresh potato residue system, from 2.20×10 ⁸ to 3.46×10 ⁷ (at least one order of magnitude). The uninoculated fresh potato dregs had mildew in some areas after being placed at room temperature for 2 days, and the potato dregs fermented with Lactobacillus plantarum did not appear mildew after being placed for 5 days (Figure 1).

Table 1 Changes in the total number of colonies in the system before and after the treatment of fresh potato residues.

It shows that this treatment method can inhibit the growth of other bacteria in the fresh potato dregs system, achieve the effect of anti-corrosion, prolong its storage period, and can be stored for more than 15 days in a closed room at room temperature, which relieves the pressure of processing fresh potato dregs with huge daily output.

Example 2

Add the following substances to the fresh potato dregs separately:

(1) Mixed enzyme solution of pectinase and cellulase with a mixing ratio of 1:4 (enzyme activity ratio); (2) pectinase and cellulase with a mixing ratio of 1:2:3 (enzyme activity ratio) Mix the enzyme solution with hemicellulase, the amount of pectinase added is 0.25U/g; (3) the mixing ratio of pectinase and cellulase is 1:1 (enzyme activity ratio), the amount of pectinase added is 3.75 U/g; (4) The amount of pectinase added was 0.25 U/g.

(2) after above-mentioned enzyme liquid and fresh potato residue are mixed, inoculation concentration is respectively 4.40 × 10 ⁹ CFU/mL Lactobacillus plantarum CCFM 8661 bacterial liquid, inoculum amount 4% (bacteria liquid volume mL/fermentation substrate mass g), after mixing evenly, spread out, seal the bag or seal it with a film. Solid-state anaerobic fermentation at 37°C for 72h. After fermentation, centrifugal dehydration was used, and blast drying was used to measure the drying characteristic curves of potato residues treated in different ways, with potato starch and microcrystalline cellulose as controls.

The results are shown in Figures 2 and 3. Compared with the untreated potato residue, the drying characteristics of the potato residue treated with enzyme combined with inoculation with Lactobacillus plantarum were significantly improved. Under the same drying conditions (55℃ as an example), compared with the untreated potato residue, the potato residue treated by the enzyme method combined with the bacteria has a lower water content. The moisture content of the potato residue was lower than 10%, while the untreated and only inoculated potato residues still had a moisture content higher than 30% after drying for 240 min. The treated potato dregs have a short drying time, and no longer have the gelatinous form of fresh potato dregs, but have a certain fluidity. The drying characteristics of the potato residue treated by enzymatic method combined with strain fermentation were better than those treated only by inoculation strain fermentation and untreated potato residue.

Example 3

Add pectinase and cellulase with a mixing ratio of 1:4 to the fresh potato residue, with the amount of pectinase added as 0.25U/g, mix well, inoculate the mixed bacterial liquid of Lactobacillus plantarum and highly active yeast, inoculate The amount is 6%, the concentration of Lactobacillus plantarum (CCFM 8661) is 3.2×10 ⁹ CFU/mL, the rehydration ratio of high-activity yeast is 40:1 (water quality: yeast powder quality), high-activity yeast live bacteria The number is 7.9×10 ⁷ CFU/mL, and the mixing ratio of the two strains is 1:2 (volume ratio). After mixing evenly, it is spread out, sealed in a sealed bag or sealed with a film. Solid-state anaerobic fermentation at 37°C for 48h. After the fermentation, the samples were centrifuged and dehydrated, and then air-dried at 55°C. Record the drying time of the sample, the moisture content at the end of drying, and the yield after drying. The results are shown in Figure 2.

The fresh potato residue (wet residue, moisture content of 92%) was fermented by adding enzymes combined with bacterial strains, and the moisture content was reduced to 10% after drying for 240 min. In addition, the treatment method of the present invention can significantly reduce the moisture content of the potato residue after centrifugation and filter-pressing. After drying, the potato residue has an estery odor and can be used as feed to improve the feeding of animals. The water content of the potato residue treated by the invention is 13.4%, and the material yield is 7.20g/100g.

Example 4

Add pectinase and cellulase with a mixing ratio of 1:3 to the fresh potato residue (wet residue, moisture content of 91%), the amount of pectinase added is 3.75U/g, and the mixture is uniform, and the inoculation concentration is 7.4× 10 ⁹ CFU/mL of Lactobacillus plantarum and highly active yeast mixed bacterial solution, the mixing ratio is 1:2 (volume ratio), and the inoculum amount of Lactobacillus plantarum (the Lactobacillus plantarum is provided by the School of Bioengineering, Jiangnan University) is 8% (mL volume of bacterial liquid/mass g of fermentation substrate), after mixing evenly, spread out, seal the bag or seal it with a membrane. Solid-state anaerobic fermentation at 37°C for 48h. After the fermentation, the sample plate frame was press-filtered and air-dried. After drying for 10s, the moisture content of the obtained sample was 12.3%, and the material yield was 5.29g/100g.

Example 5

Add pectinase 0.25U/g to the fresh potato residue, the mixing ratio of pectinase and cellulase is 1:1, mix evenly, and inoculate Lactobacillus plantarum with a concentration of 7.4×10 ⁹ CFU/mL (CCTCC M 2017138) Mix bacterial liquid with highly active yeast, the mixing ratio is 1:1 (volume ratio), the inoculum amount of Lactobacillus plantarum is 8% (bacteria liquid volume mL/fermentation substrate mass g), after mixing evenly, spread it out and seal the bag Sealed or closed with membrane. Solid-state anaerobic fermentation at 37°C for 60h. After fermentation, a certain amount of fermentation product was centrifuged at 4500 rpm for 15 min, and the supernatant was taken to measure the organic acid content. A certain amount of fermented samples were freeze-dried to determine their crude protein content.

Quantitative lactic acid determination by high performance liquid chromatography in potato residue after enzymatic method combined with strain fermentation showed that the lactic acid content increased from 0.0012mg/g in raw potato residue to 4.787mg/g. Crude protein content increased from 9.80% (w/w) to 13.92% (w/w).

Comparative Example 1

The specific embodiment is the same as in Example 4, except that no enzyme or strain is added, or only strain is inoculated for fermentation, or only enzyme is added for treatment.

The untreated potato residue and the fermented potato residue only inoculated with bacterial cells are typical gelatinous, with high viscosity and no fluidity, and cannot be dried by air flow. The fermentation level of the potato residue treated with only enzyme was reduced, the organic acid content was only half of that of the enzyme combined with bacterial strain fermentation treatment, and the antibacterial performance was greatly reduced, and obvious mildew began to appear after 5 days.

Comparative Example 2

The specific embodiment is the same as Example 3, except that when the amount of pectinase added is 13 U/g, the moisture content of the sample is lower than 10% after drying, and the yield of the product is only 3.83 g/100 g.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone who is familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention should be defined by the claims.

Claims (6)

1. a fermentation method of potato dregs, is characterized in that, described method is fermentation substrate with fresh potato dregs, adds in pectinase, cellulase, hemicellulase with the addition of 0.25～7.5U/g At least one of Lactobacillus plantarum and yeast is inoculated, and enzymolysis and anaerobic solid-state fermentation are carried out simultaneously at 25 to 39 ° C; the inoculation is 2 to 14% (bacteria liquid volume mL/fermentation substrate mass g) The inoculation amount of Lactobacillus plantarum and yeast mixed bacterial liquid is inoculated, and the concentration of the bacterial liquid is (1.0～9.9)×10 ⁹ CFU/mL; the ratio of the bacterial cells of Lactobacillus plantarum and yeast in the bacterial liquid is 1: 1 to 5; volume of bacterial liquid: the mass of fermentation substrate is 1 to 7: 50 mL/g; the enzymatic hydrolysis is any one of the following processes: (a) adding one of pectinase, cellulase and hemicellulase in an amount of 0.25-7.5 U/g; (b) Pectinase and cellulase are added in a ratio of 1-3:1-4, and pectinase is added to the fresh potato residue in an addition amount of 0.25-3.75U/g, and the total enzyme addition amount is 0.25- 7.5U/g; (c) In the enzymatic hydrolysis treatment, pectinase: cellulase: hemicellulase is added in a ratio of 1-3:1-10:1-5, and pectinase is added in a ratio of 0.25-3.75 U/g The total amount of enzyme added is 0.25-7.5U/g. 2. The method according to claim 1, wherein the moisture content of the fresh potato residue is 85-95%. 3. The method according to claim 1, characterized in that, after the solid-state anaerobic fermentation, mechanical dehydration and drying are also performed. 4. The method according to claim 3, wherein the fermentation adopts a sealed bag, a pit stacking seal, or an airtight fermentation tank. 5. The method according to claim 3, wherein the dehydration method is plate and frame filter press, screw extrusion, centrifugal dehydration or a combination thereof; the drying method is blast drying, airflow drying, circulation drying, Flash drying or a combination thereof. 6. The potato dregs prepared by any one of claims 1 to 5.

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