A pickled vegetable cutting process of pickled vegetable residue recycling

Abstract

The present application is suitable for recycling technical field, provide a kind of pickled vegetable cutting process's vegetable residue recycling process, including to vegetable residue microwave pretreatment, again carry out cold water countercurrent extraction and phytochemical enrichment, obtain phytochemical concentrate and after extraction vegetable residue;Gradient desalination and high-salt wastewater membrane distillation treatment are carried out to after extraction vegetable residue, after ending again carry out low-temperature ultrafine grinding and composite enzymolysis;Metabolic precursor directional fermentation and selective bacteriostasis;Membrane separation grading;Join β-cyclodextrin, haematococcus extract and tea polyphenol, carry out spray drying, prepare the composite feed additive rich in small molecule active peptide, astaxanthin and tea polyphenol;Xylose oligomer-puffed feed granulation;Haematococcus extract in the field of aquaculture microalgae is introduced into pickled vegetable residue spray drying system, astaxanthin, tea polyphenol and active peptide form triple antioxidant synergistic network.

Description

Technical Field

[0001] This invention relates to the field of recycling and reuse technology, and more specifically, to a process for recycling and reusing vegetable scraps from the process of cutting pickled vegetables. Background Technology

[0002] Pickled vegetables are a general term for various vegetable products made primarily from fresh vegetables through pickling or marinating. Depending on the processing techniques and auxiliary materials, pickled vegetables can be categorized into several types, including marinated vegetables, salted vegetables, soy sauce-pickled vegetables, sugar-pickled vegetables, vinegar-pickled vegetables, sweet and sour pickled vegetables, shrimp oil-pickled vegetables, and fermented vegetables. As a traditional Chinese food, pickled vegetables have a cultivation and pickling history of over 3,000 years, representing a valuable part of China's culinary culture. Cutting is a crucial step in the processing of pickled vegetables. After fresh vegetables are salted and made into salted brines, they need to be cut into different shapes such as chunks, cubes, shreds, and slices for subsequent marinating or direct packaging. Inevitably, this process generates a large amount of vegetable scraps, peels, tips, roots, and offal. Taking pickled mustard tuber (Zha Cai) processing as an example, in addition to the main product, pickled mustard tuber, the processing of Zha Cai also produces a large amount of byproducts such as vegetable scraps, peels, tips, and pickled mustard tuber brine.

[0003] The large amount of vegetable scraps generated during the cutting of pickled vegetables is difficult to handle due to their high salt concentration or distinctive odor, and cannot be arbitrarily dumped, otherwise it would cause environmental pollution. Currently, the main method of disposal for these scraps is centralized landfill, which not only results in a serious waste of biomass resources and requires a large amount of land, but also incurs additional disposal costs for enterprises. Meanwhile, pickled vegetable scraps still contain rich dietary fiber, protein, minerals, and other nutrients, possessing high potential for resource utilization. Therefore, recycling and reusing the vegetable scraps generated during the cutting of pickled vegetables can not only maximize the utilization of biomass resources and turn waste into treasure, but also effectively reduce environmental pressure and promote the green upgrading and sustainable development of the traditional pickled vegetable industry. Some research and technological explorations have already been conducted in this direction.

[0004] Current technologies for recycling and reusing pickled vegetable residue still have many shortcomings. Pickled vegetable residue absorbs a high amount of salt during the pickling and cutting processes. Existing technologies often use methods such as soaking in water for desalination, but desalination is often incomplete, leaving a certain amount of salt residue. At the same time, the residue still contains abundant nutrients. During open fermentation or storage, while the residual salt can inhibit the growth of some microorganisms, it cannot effectively prevent contamination by salt-tolerant bacteria. These salt-tolerant bacteria (such as some salt-tolerant yeasts, molds, and putrefactive bacteria) multiply rapidly during fermentation, competing with the target fermentation bacteria for nutrients, producing harmful metabolites, leading to fermentation failure or unstable product quality. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies: after desalination, the vegetable residue of pickled vegetables still retains a certain amount of salt and a large amount of nutrients, which are easily contaminated by miscellaneous bacteria (especially salt-tolerant bacteria) during open fermentation, leading to fermentation failure or unstable product quality. Therefore, this invention proposes a process for recycling and reusing vegetable residue during the cutting process of pickled vegetables.

[0006] The specific technical solution is as follows: a process for recycling and reusing vegetable scraps during the cutting process of pickled vegetables, including the following steps:

[0007] Vegetable residue generated during the cutting of pickled vegetables was collected and pretreated with microwaves. After pretreatment, it underwent cold water countercurrent extraction and phytochemical enrichment to obtain a concentrated phytochemical solution and the extracted vegetable residue. The extracted residue was then subjected to gradient desalination and high-salt wastewater membrane distillation, followed by low-temperature ultrafine grinding and compound enzymatic hydrolysis. The pH of the enzymatic hydrolysate was adjusted to 5.5-6.5, and the concentrated phytochemical solution, L-glutamic acid, and ε-polylysine were added. The mixture was first inoculated with lactic acid bacteria for anaerobic fermentation, then with *Candida utilis* for aerobic fermentation, and finally with *Bacillus subtilis* for a secondary aerobic fermentation. Membrane separation and fractionation were performed to obtain a supernatant and precipitate. The supernatant was further separated by ultrafiltration to obtain an active peptide solution and a retentate.

[0008] Astaxanthin, active peptides and tea polyphenols are co-spray dried: 0.5%-2% β-cyclodextrin, 0.05%-0.3% Haematococcus pluvialis extract and 0.1%-0.5% tea polyphenols are added to the active peptide solution and spray dried. The inlet air temperature is 160-200℃ and the outlet air temperature is 70-90℃ to obtain a compound feed additive rich in small molecule active peptides, astaxanthin and tea polyphenols.

[0009] Xylooligosaccharide-expanded feed pelleting.

[0010] A further optimized technical solution, the directed fermentation and selective inhibition of metabolic precursors, includes the following steps: The pH of the enzymatic hydrolysate from step one is adjusted to 5.5-6.5, and phytochemical concentrate, L-glutamic acid, and ε-polylysine are added. First, lactic acid bacteria are inoculated for anaerobic fermentation at 30-37℃ for 12-24 hours. Then, *Candida utilis* is inoculated for aerobic fermentation at 28-32℃ for 8-16 hours. Finally, *Bacillus subtilis* is inoculated for a secondary aerobic fermentation at 35-40℃ for 6-12 hours. The amount of phytochemical concentrate added is 1%-5% of the enzymatic hydrolysate volume, the amount of L-glutamic acid added is 0.5%-2% of the enzymatic hydrolysate mass, and the amount of ε-polylysine added is 0.01%-0.1% of the enzymatic hydrolysate mass.

[0011] In a further preferred embodiment, the ε-polylysine has a molecular weight of 3500-4500 Da, a degree of polymerization of 25-35, and a purity of not less than 95%; the lactic acid bacteria are a mixture of Lactobacillus plantarum and Lactobacillus acidophilus, with an inoculation ratio of 1:1 and an inoculation amount of 2%-5% of the enzymatic hydrolysate volume; the inoculation amount of Candida utilis is 1%-3% of the enzymatic hydrolysate volume; and the inoculation amount of Bacillus subtilis is 1%-3% of the enzymatic hydrolysate volume.

[0012] A further preferred technical solution is that membrane separation and fractionation includes the following steps: centrifuging the fermented material to obtain supernatant and precipitate, and then separating the supernatant through an ultrafiltration membrane to obtain an active peptide solution with a molecular weight less than 10 kDa and a retentate with a molecular weight greater than 10 kDa; wherein, the ultrafiltration membrane is a polyethersulfone hollow fiber ultrafiltration membrane with a molecular weight cutoff of 10 kDa and an operating pressure of 0.1-0.3 MPa.

[0013] Further optimized technical solutions include an astaxanthin content of 3%-8% in the Haematococcus pluvialis extract; and a green tea extract containing epigallocatechin gallate esters of no less than 50% tea polyphenols.

[0014] A further optimized technical solution involves homogenizing β-cyclodextrin, Haematococcus pluvialis extract, and tea polyphenols under high pressure before spray drying to form nano-inclusion complexes. The homogenization pressure is 50-100 MPa, and the homogenization is performed 2-4 times.

[0015] A further preferred technical solution, xylooligosaccharide-expanded feed granulation, includes the following steps: mixing the precipitate obtained in step three with the retentate obtained in step four, adding xylooligosaccharide at a mass of 0.5%-2% of the mixture, adjusting the moisture content to 25%-35%, and feeding it into a twin-screw extruder for extrusion and expansion treatment at an expansion temperature of 120-160℃ and a screw speed of 200-400 rpm. After expansion, the pellets are cut and dried to obtain xylooligosaccharide-containing extruded feed pellets.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. Introducing ε-polylysine into the fermentation system of pickled vegetable residues, the inhibitory effect of ε-polylysine on Gram-negative bacteria was significantly stronger than that on Gram-positive target bacteria, achieving precise antibacterial inhibition. The selective antibacterial effect of ε-polylysine improved the fermentation success. The polycationic properties of ε-polylysine can form nanocomplexes with the polyanionic regions of active peptides through electrostatic interactions, thereby improving the intestinal delivery rate of active peptides and achieving efficient delivery and bioavailability of active peptides.

[0018] 2. The Haematococcus pluvialis extract from the aquatic microalgae aquaculture field was introduced into the spray drying system of pickled vegetable residue. Astaxanthin, tea polyphenols and active peptides formed a triple antioxidant synergistic network, which improved the DPPH free radical scavenging rate of the product and the retention rate of astaxanthin in spray drying.

[0019] 3. Astaxanthin in Haematococcus pluvialis extract is encapsulated in β-cyclodextrin to form a stable astaxanthin-cyclodextrin inclusion complex, which can protect astaxanthin and active peptides simultaneously during spray drying; the polysaccharide components in Haematococcus pluvialis extract can act as a natural emulsifier to improve the pelleting properties and water stability of extruded feed.

[0020] 4. Between microwave pretreatment and gradient desalination, a cold water countercurrent extraction step is added. Low-temperature water at 4-10℃ is used to selectively extract heat-sensitive glucosinolates, flavonoids and other phytochemicals in vegetable residue. After nanofiltration and concentration, part of the extract is reused in subsequent enzymatic hydrolysis and fermentation steps, and the other part is spray-dried to produce phytochemical feed additives.

[0021] In the multi-strain stepwise fermentation stage of lactic acid bacteria, L-glutamic acid is added as a precursor to induce lactic acid bacteria to produce γ-aminobutyric acid. At the same time, a portion of the phytochemical extract (containing natural glucosinolates and their degradation products) enriched in the bacteria is added to the fermentation system as a natural metabolic regulator to guide the fermentation toward producing more functional metabolites.

[0022] The high-salt wastewater generated from gradient desalination is concentrated by membrane distillation to recover salt (which is then reused in the production of pickled vegetables). The remaining concentrated liquid contains phytochemicals and minerals dissolved from the vegetable residue, which are then spray-dried to produce a mineral-phytochemical composite additive. In the spray-drying step, in addition to adding β-cyclodextrin, tea polyphenols are introduced as an antioxidant synergist. Tea polyphenols can not only protect the active peptides from oxidative damage during the high-temperature spray-drying process, but also produce a synergistic antioxidant effect with the antioxidant peptides in the active peptides.

[0023] 5. In the extrusion and granulation step, xylooligosaccharides are added as a prebiotic component. Xylooligosaccharides can selectively proliferate bifidobacteria and lactic acid bacteria in the animal intestines, and form a prebiotic-postbiotic synergy with the residual probiotic metabolites in the product (from multi-strain fermentation), thereby enhancing the intestinal health regulation function of the feed.

[0024] 6. The vegetable residue recycling process of the present invention produces a compound feed additive rich in active peptides, astaxanthin, tea polyphenols and γ-aminobutyric acid and functional extruded feed pellets containing xylooligosaccharides, realizing product diversification and ultra-high value.

[0025] 7. In the three-stage countercurrent extraction, the fresh solvent comes into contact with the fresh material in the first stage, resulting in the highest extraction rate. As the concentration of phytochemicals in the material decreases, an extract containing a certain concentration of phytochemicals is used in each stage to maintain a large concentration gradient, driving the continuous dissolution of phytochemicals. Attached Figure Description

[0026] Figure 1 A bar chart showing the carotenoid extraction rates of groups A and B;

[0027] Figure 2 A bar chart showing the total phenol content of groups A and B;

[0028] Figure 3 Line graph showing the DPPH clearance rate of groups F and I;

[0029] Figure 4 This is a line graph showing the ABTS statistics for groups F and I. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0031] Example 1

[0032] A process for recycling and reusing vegetable scraps from the process of cutting pickled vegetables includes the following steps:

[0033] Step 1: Collect the vegetable residue generated during the cutting of pickled vegetables and pre-treat it with microwave. After that, perform cold water countercurrent extraction and phytochemical enrichment to obtain phytochemical concentrate and extracted vegetable residue. Then, perform gradient desalination and high-salt wastewater membrane distillation on the extracted vegetable residue, followed by low-temperature ultrafine grinding and compound enzymatic hydrolysis.

[0034] Step 2: Directed fermentation and selective inhibition of metabolic precursors

[0035] Adjust the pH of the enzymatic hydrolysate from step one to 5.5-6.5, add phytochemical concentrate, L-glutamic acid and ε-polylysine, first inoculate with lactic acid bacteria for anaerobic fermentation, then inoculate with Candida utilis for aerobic fermentation, and finally inoculate with Bacillus subtilis for secondary aerobic fermentation.

[0036] Introducing ε-polylysine into the fermentation system of pickled vegetable residues, the inhibitory effect of ε-polylysine on Gram-negative bacteria was significantly stronger than that on Gram-positive target bacteria, achieving precise antibacterial inhibition. The selective antibacterial effect of ε-polylysine improved the fermentation success.

[0037] Step 3: Membrane separation and fractionation to obtain supernatant and precipitate. The supernatant is then separated by ultrafiltration membrane to obtain active peptide solution and retentate.

[0038] Step 4: Spray drying of astaxanthin, active peptides, and tea polyphenols.

[0039] Add 0.5%-2% β-cyclodextrin, 0.05%-0.3% Haematococcus pluvialis extract and 0.1%-0.5% tea polyphenols to the active peptide solution, and spray dry it with an inlet air temperature of 160-200℃ and an outlet air temperature of 70-90℃ to obtain a compound feed additive rich in small molecule active peptides, astaxanthin and tea polyphenols.

[0040] By introducing Haematococcus pluvialis extract from the field of aquatic microalgae cultivation into the spray drying system of pickled vegetable residue, astaxanthin, tea polyphenols and active peptides form a triple antioxidant synergistic network, which improves the DPPH free radical scavenging rate of the product and the retention rate of astaxanthin in spray drying.

[0041] Step 5: Xylooligosaccharide-expanded feed pelleting.

[0042] The polycationic properties of ε-polylysine can form nanocomposites with the polyanionic regions of bioactive peptides through electrostatic interactions, thereby improving the intestinal delivery rate of bioactive peptides and achieving efficient delivery and bioavailability of bioactive peptides.

[0043] Astaxanthin in Haematococcus pluvialis extract is encapsulated in β-cyclodextrin to form a stable astaxanthin-cyclodextrin inclusion complex, which can protect astaxanthin and active peptides simultaneously during spray drying; the polysaccharide components in Haematococcus pluvialis extract can act as natural emulsifiers to improve the pelleting properties and water stability of extruded feed.

[0044] The vegetable residue recycling process of this invention produces a compound feed additive rich in active peptides, astaxanthin, tea polyphenols and γ-aminobutyric acid, as well as functional extruded feed pellets containing xylooligosaccharides, thus achieving product diversification and ultra-high value.

[0045] Furthermore, step one includes the following steps:

[0046] S1. Collect vegetable scraps generated during the cutting of pickled vegetables. After sorting and removing impurities, pre-treat the vegetable scraps with microwave at a frequency of 2450MHz for 30-120 seconds.

[0047] S2, Cold Water Countercurrent Extraction and Phytochemical Enrichment

[0048] The microwave-pretreated vegetable residue was subjected to countercurrent extraction in cold water at 4-10℃ for 30-120 minutes. The extract was then concentrated using a nanofiltration membrane to obtain a phytochemical concentrate and the extracted vegetable residue. The material-to-liquid ratio for countercurrent extraction was 1:5-1:15. Ultrasonic-assisted extraction was used during the process, with an ultrasonic frequency of 20-40 kHz and a power density of 0.2-1 W / cm³. 2 The molecular weight cutoff of nanofiltration membranes is 150-300 Da, and the operating pressure is 0.5-1.5 MPa.

[0049] Between microwave pretreatment and gradient desalination, a cold water countercurrent extraction step is added. Low-temperature water at 4-10℃ is used to selectively extract heat-sensitive phytochemicals such as glucosinolates and flavonoids from vegetable residue. After nanofiltration and concentration, part of the extract is reused in subsequent enzymatic hydrolysis and fermentation steps, and the other part is spray-dried to produce phytochemical feed additives.

[0050] S3, gradient desalination

[0051] The extracted vegetable residue was placed in a first desalination tank and a second desalination tank for two-stage gradient soaking and desalination. The mass concentration of brine in the first desalination tank was 3%-5%, and the mass concentration of brine in the second desalination tank was 0.5%-1.5%. The soaking times were 2-4 hours and 1-2 hours, respectively. After desalination, the salt content of the vegetable residue was reduced to below 1.5%.

[0052] S4. High-salt wastewater membrane distillation treatment:

[0053] The desalination wastewater generated during gradient desalination is collected and concentrated by membrane distillation to obtain crystalline salt and mineral-phytochemical concentrate. The membrane distillation uses a polytetrafluoroethylene hollow fiber membrane with a pore size of 0.1-0.5 μm, an operating temperature of 50-70℃, and a vacuum degree of 0.05-0.1 MPa.

[0054] The high-salt wastewater generated from gradient desalination is concentrated by membrane distillation to recover salt (which is then reused in the production of pickled vegetables). The remaining concentrated liquid contains phytochemicals and minerals dissolved from the vegetable residue, which are then spray-dried to produce a mineral-phytochemical composite additive. In the spray-drying step, in addition to adding β-cyclodextrin, tea polyphenols are introduced as an antioxidant synergist. Tea polyphenols can not only protect the active peptides from oxidative damage during the high-temperature spray-drying process, but also produce a synergistic antioxidant effect with the antioxidant peptides in the active peptides.

[0055] S5, Low-Temperature Ultrafine Grinding

[0056] The desalted vegetable residue was ultra-finely pulverized at a low temperature of -10℃ to -20℃ until it was pulverized into ultra-fine powder with a particle size of 10-50μm.

[0057] S6, compound enzymatic hydrolysis

[0058] Ultrafine powder and water are mixed at a mass ratio of 1:3 to 1:5, and a compound enzyme preparation is added for enzymatic hydrolysis. The compound enzyme preparation consists of cellulase, hemicellulase, pectinase, and neutral protease in a mass ratio of 2:1:1:1, with an addition amount of 0.5%-2% of the ultrafine powder mass. The enzymatic hydrolysis temperature is 45-55℃, and the hydrolysis time is 2-6 hours. After hydrolysis, the enzyme is inactivated. Ultrasonic assisted hydrolysis is used during the process, with an ultrasonic frequency of 20-40 kHz and a power density of 0.5-2 W / cm³. 2 .

[0059] The second step, the directed fermentation and selective inhibition of metabolic precursors, includes the following steps: adjusting the pH of the enzymatic hydrolysate from the first step to 5.5-6.5, adding phytochemical concentrate, L-glutamic acid, and ε-polylysine; first, inoculating with lactic acid bacteria for anaerobic fermentation at 30-37℃ for 12-24 hours; then inoculating with Candida utilis for aerobic fermentation at 28-32℃ for 8-16 hours; finally, inoculating with Bacillus subtilis for secondary aerobic fermentation at 35-40℃ for 6-12 hours; wherein the amount of phytochemical concentrate added is 1%-5% of the enzymatic hydrolysate volume, the amount of L-glutamic acid added is 0.5%-2% of the enzymatic hydrolysate mass, and the amount of ε-polylysine added is 0.01%-0.1% of the enzymatic hydrolysate mass.

[0060] In the multi-strain stepwise fermentation stage of lactic acid bacteria, L-glutamic acid is added as a precursor to induce lactic acid bacteria to produce γ-aminobutyric acid. At the same time, a portion of the phytochemical extract (containing natural glucosinolates and their degradation products) enriched in the bacteria is added to the fermentation system as a natural metabolic regulator to guide the fermentation toward producing more functional metabolites.

[0061] The ε-polylysine has a molecular weight of 3500-4500 Da, a degree of polymerization of 25-35, and a purity of not less than 95%. The ε-polylysine has an inhibition rate of more than 70% against miscellaneous bacteria in the fermentation system, while its activity inhibition rate against lactic acid bacteria, Candida utilis, and Bacillus subtilis is less than 10%. The lactic acid bacteria are a mixture of Lactobacillus plantarum and Lactobacillus acidophilus, with an inoculation ratio of 1:1 and an inoculation amount of 2%-5% of the enzyme hydrolysate volume. The inoculation amount of Candida utilis is 1%-3% of the enzyme hydrolysate volume. The inoculation amount of Bacillus subtilis is 1%-3% of the enzyme hydrolysate volume.

[0062] The membrane separation and fractionation in step three includes the following steps: centrifuging the fermented material to obtain supernatant and precipitate, and then separating the supernatant through an ultrafiltration membrane to obtain an active peptide solution with a molecular weight less than 10 kDa and a retentate with a molecular weight greater than 10 kDa; wherein, the ultrafiltration membrane is a polyethersulfone hollow fiber ultrafiltration membrane with a molecular weight cutoff of 10 kDa and an operating pressure of 0.1-0.3 MPa.

[0063] In step four, the astaxanthin content in the Haematococcus pluvialis extract is 3%-8%; the tea polyphenols are from green tea extract, in which the content of epigallocatechin gallate is not less than 50%.

[0064] In step four, β-cyclodextrin, Haematococcus pluvialis extract, and tea polyphenols are subjected to high-pressure homogenization before spray drying to form nano-inclusion complexes. The homogenization pressure is 50-100 MPa, and the homogenization is performed 2-4 times.

[0065] The fifth step of the xylooligosaccharide-expanded feed granulation includes the following steps: mixing the precipitate obtained in the third step with the retentate obtained in the fourth step, adding 0.5%-2% xylooligosaccharide by mass of the mixture, adjusting the moisture content to 25%-35%, and feeding it into a twin-screw extruder for extrusion and expansion. The expansion temperature is 120-160℃, the screw speed is 200-400rpm, and after expansion, the pellets are cut and dried to obtain xylooligosaccharide-containing extruded feed pellets. The degree of polymerization of the xylooligosaccharide is 2-7, and the purity is not less than 70%.

[0066] The process of recycling and reusing vegetable residue from the pickled vegetable cutting process is used to produce pickled vegetable residue feed. The pickled vegetable residue feed consists of two parts: compound feed additives and extruded feed pellets. The compound feed additives contain more than 60% small molecule peptides in their total protein, 0.05%-0.5% astaxanthin, 0.5%-3% tea polyphenols, and 1%-5% γ-aminobutyric acid. The extruded feed pellets contain 0.3%-1.5% xylooligosaccharides and have a gelatinization degree of more than 85%.

[0067] In the extrusion and granulation process, xylooligosaccharides are added as a prebiotic component. Xylooligosaccharides can selectively proliferate bifidobacteria and lactic acid bacteria in the animal gut, forming a prebiotic-postbiotic synergy with the residual probiotic metabolites in the product (from multi-strain fermentation), thereby enhancing the intestinal health regulation function of the feed.

[0068] Example 2

[0069] This embodiment is a further refinement of Embodiment 1:

[0070] A process for recycling and reusing vegetable scraps from the process of cutting pickled vegetables includes the following steps:

[0071] (1) Raw material collection and microwave pretreatment: 100 kg of vegetable peel, broken vegetables and vegetable tips generated during the cutting process of pickled mustard tuber were collected, sorted and cleaned, and then microwaved (2450 MHz, 60 seconds) to achieve a cell wall rupture rate of 65%.

[0072] (2) Cold water countercurrent extraction and phytochemical enrichment: Cold water countercurrent extraction at 6℃ (solid-to-liquid ratio 1:10, 60 minutes, ultrasonic 28kHz, 0.5W / cm) 2 The extract was concentrated by nanofiltration (molecular weight cutoff 200 Da, 1.0 MPa) to obtain 4.2 L of phytochemical concentrate (total phenols 6.5 mg / mL, glucosinolates 2.3 mg / mL).

[0073] (3) Gradient desalination: First desalination tank (4% brine, 25℃, 3 hours) → draining for 20 minutes → Second desalination tank (1% brine, 25℃, 1.5 hours), salt content after desalination is 1.0%.

[0074] (4) High-salt wastewater membrane distillation treatment: Desalinated wastewater was distilled by membrane (PTFE hollow fiber membrane, 0.2μm, 60℃, 0.08MPa) to obtain 3.0kg of crystalline salt and 14L of mineral-phytochemical concentrate.

[0075] (5) Low temperature ultrafine grinding: ultrafine grinding at -15℃ to 20-40μm.

[0076] (6) Compound enzymatic hydrolysis: Mix ultrafine powder with water in a 1:4 ratio, add compound enzyme (1%, cellulase: hemicellulase: pectinase: neutral protease = 2:1:1:1), and enzymatically hydrolyze at 50℃ for 4 hours (ultrasound 28kHz, 1W / cm). 2 ), inactivate enzymes at 90℃ for 12 minutes.

[0077] (7) Directed fermentation and selective antibacterial activity of metabolic precursors: The pH of the enzymatic hydrolysate was adjusted to 6.0, and phytochemical concentrate (3% of the volume of the enzymatic hydrolysate), L-glutamic acid (1% of the volume of the enzymatic hydrolysate) and ε-polylysine (0.05% of the volume of the enzymatic hydrolysate, molecular weight 4000 Da, purity 96%) were added.

[0078] Phase 1: Inoculate with Lactobacillus plantarum and Lactobacillus acidophilus at a ratio of 1:1 (addition amount is 3% of the volume of the enzymatic hydrolysate), and anaerobically incubate at 35°C for 18 hours.

[0079] Second stage: Inoculate with Candida utilis (addition amount is 2% of the volume of the enzyme hydrolysate), and aerobic treatment at 30°C for 12 hours;

[0080] Stage 3: Inoculation with Bacillus subtilis (2% of the enzymatic hydrolysate volume), aerobic fermentation at 37℃ for 8 hours. After fermentation, the γ-aminobutyric acid (GABA) content was 6.5 mg / g. Testing showed that ε-polylysine inhibited the growth of miscellaneous bacteria by 78% and the activity of lactic acid bacteria by only 6%.

[0081] (8) Membrane separation and fractionation: Centrifuge at 6000 rpm for 15 minutes, and separate the supernatant through an ultrafiltration membrane (molecular weight cutoff 10 kDa, 0.2 MPa) to obtain active peptide solution and retentate.

[0082] (9) Astaxanthin-Active Peptide-Tea Polyphenol Ternary Spray Drying: β-cyclodextrin (1% of active peptide solution mass), Haematococcus pluvialis extract (0.15% of active peptide solution mass, astaxanthin content 5%), and tea polyphenols (0.3% of active peptide solution mass, EGCG content 55%) were added to the active peptide solution. After high-pressure homogenization (80MPa, 3 times), spray drying was performed (inlet air 180℃, outlet air 80℃). 2.9 kg of compound feed additive was obtained. Detection: Small molecule peptide content 68%, astaxanthin content 0.28%, tea polyphenol content 1.9%, γ-aminobutyric acid content 3.8%, DPPH free radical scavenging rate 92%, astaxanthin retention rate 92%.

[0083] (10) Xylooligosaccharide-expanded feed granulation: The precipitate and retentate were mixed, and xylooligosaccharide (1%, degree of polymerization 3-5, purity 75%) was added. The moisture content was adjusted to 30%, and the mixture was extruded and expanded using a twin-screw extruder (140℃, 300rpm). The mixture was then fluidized in a 70℃ bed to dry to a moisture content of 8%, yielding 51kg of extruded feed pellets. The gelatinization degree was 92%, the xylooligosaccharide content was 0.8%, and the multiplication factor for Bifidobacteria was 7.2 times.

[0084] Example 3

[0085] The only difference between this embodiment and Embodiment 2 is that:

[0086] (7) Directed fermentation and selective antibacterial activity of metabolic precursors: The pH of the enzymatic hydrolysate was adjusted to 6.0, and phytochemical concentrate (4% of the volume of the enzymatic hydrolysate), L-glutamic acid (1.5% of the volume of the enzymatic hydrolysate) and ε-polylysine (0.05% of the volume of the enzymatic hydrolysate, molecular weight 4000 Da, purity 96%) were added.

[0087] Phase 1: Inoculate with Lactobacillus plantarum and Lactobacillus acidophilus at a ratio of 1:1 (addition amount is 4% of the volume of the enzymatic hydrolysate), and anaerobically incubate at 35°C for 20 hours.

[0088] Second stage: Inoculate with Candida utilis (addition amount is 2% of the volume of the enzyme hydrolysate), and aerobic treatment at 30°C for 12 hours;

[0089] Stage 3: Inoculation with Bacillus subtilis (2% of the enzymatic hydrolysate volume), aerobic fermentation at 37℃ for 10 hours. After fermentation, the γ-aminobutyric acid (GABA) content was 6.5 mg / g. Testing showed that ε-polylysine inhibited the growth of miscellaneous bacteria by 78% and the activity of lactic acid bacteria by only 6%.

[0090] (9) Astaxanthin-Active Peptide-Tea Polyphenol Ternary Spray Drying: β-cyclodextrin (1.5% of the active peptide solution mass), Haematococcus pluvialis extract (0.2% of the active peptide solution mass, astaxanthin content 5%), and tea polyphenols (0.2% of the active peptide solution mass, EGCG content 55%) were added to the active peptide solution. After high-pressure homogenization (80MPa, 3 times), spray drying was performed (inlet air temperature 180℃, outlet air temperature 80℃). 2.9 kg of compound feed additive was obtained. Detection: Small molecule peptide content 68%, astaxanthin content 0.28%, tea polyphenol content 1.9%, γ-aminobutyric acid content 3.8%, DPPH free radical scavenging rate 92%, astaxanthin retention rate 92%.

[0091] Example 4

[0092] The only difference between this embodiment and Embodiment 1 is that "cold water countercurrent extraction and phytochemical enrichment" is replaced with "multi-stage countercurrent extraction and phytochemical enrichment". Multi-stage countercurrent extraction and phytochemical enrichment includes the following steps:

[0093] S1, Three-stage countercurrent extraction

[0094] The microwave-pretreated vegetable residue was fed into a three-stage countercurrent extraction system. The extraction solvent was cold water at 4-10°C, with food-grade ethanol (5%-15% by volume) or food-grade 1,2-propanediol (3%-10% by volume) added as a solubilizer. The specific parameters for the three-stage countercurrent extraction system were: first stage: solid-liquid ratio 1:5-1:8, extraction time 20-40 minutes; second stage: solid-liquid ratio 1:4-1:6, extraction time 15-30 minutes; third stage: solid-liquid ratio 1:3-1:5, extraction time 10-20 minutes. Ultrasonic-assisted extraction was used throughout the process, with an ultrasonic frequency of 20-40 kHz and a power density of 0.2-1 W / cm³. 2 ;

[0095] Three-stage countercurrent extraction features: the first stage involves contact between fresh solvent and fresh material, resulting in the highest extraction rate; as the concentration of phytochemicals in the material decreases, an extract solution containing a certain concentration of phytochemicals is used in each stage, maintaining a large concentration gradient to drive continuous dissolution of phytochemicals. Compared to single-stage extraction, three-stage countercurrent extraction can increase the phytochemical extraction rate from 65%-75% to 90%-95%. Although the total extraction time is slightly longer, the total volume of the extract solution is reduced, thus lowering the load on subsequent nanofiltration concentration.

[0096] Food-grade ethanol (5%-15% by volume) or food-grade 1,2-propanediol (3%-10% by volume) is added to the extraction solvent as a green solubilizer. Pure water has a reasonable extraction effect on moderately polar phytochemicals such as polyphenols and flavonoids, but its extraction efficiency for fat-soluble phytochemicals such as carotenoids and lutein is extremely low. Food-grade ethanol (5%-15%) can improve the solubility of polyphenols and flavonoids. Propylene glycol has both hydrophilic and lipophilic properties and can solubilize both polar and non-polar phytochemicals. Both are food-grade solvents with high safety, and small amounts of residue will not affect the safety of subsequent feed products. Ethanol can completely evaporate during the subsequent spray drying process and will not remain in the product.

[0097] Microwave pretreatment breaks down cell walls, solubilizers allow phytochemicals released from cells to dissolve more fully in the extract, and triple countercurrent ensures a continuous concentration gradient between the extract and the material; triple superposition increases the total phytochemical extraction rate from 65%-75% to 92%-97%.

[0098] S2, Extract fractionation membrane treatment

[0099] The combined extract obtained from the three-stage countercurrent extraction was sequentially passed through:

[0100] Ceramic microfiltration membranes (pore size 0.1-0.5μm) remove suspended particles and cell debris;

[0101] Ultrafiltration membranes (5-10 kDa molecular weight cutoff) remove large molecular colloids and polysaccharides;

[0102] Nanofiltration membranes (molecular weight cutoff 150-300 Da, operating pressure 0.5-1.5 MPa) are used to selectively concentrate phytochemicals to obtain phytochemical concentrate and nanofiltration permeate.

[0103] The pretreatment combination of ceramic membrane microfiltration and ultrafiltration can effectively remove suspended solids and macromolecular impurities, protecting nanofiltration membranes from fouling. The molecular weight cutoff of nanofiltration membranes (150-300 Da) lies precisely between small molecule phytochemicals (polyphenols, flavonoids, glucosinolates, etc., typically with molecular weights of 200-600 Da) and macromolecular impurities, enabling selective concentration.

[0104] The three-stage membrane separation of microfiltration, ultrafiltration, and nanofiltration constitutes a complete chain of impurity removal, purification, and concentration. Specifically, microfiltration removes suspended solids, which helps extend the life of ultrafiltration membranes; ultrafiltration removes macromolecular colloids, which helps extend the life of nanofiltration membranes; and nanofiltration selectively concentrates phytochemicals, which helps increase the total phenol content in the concentrate from 2-3 mg / mL in the original extract to 15-25 mg / mL. Membrane fouling rate is reduced by more than 60%, and the nanofiltration membrane cleaning cycle is extended from 7 days to more than 30 days.

[0105] S3. Closed-loop reuse of extraction residue: After collecting the nanofiltration permeate, it is completely reused in the next batch of three-stage countercurrent extraction as supplementary water for the extraction solvent.

[0106] By using liquid recycling, three-stage countercurrent extraction, and solubilizer to form a closed-loop extraction system, water consumption is reduced by 70%-80%, and the total recovery rate of phytochemicals is increased from 65%-75% to over 95%.

[0107] The total phenol content in the phytochemical concentrate has been increased from 2-3 mg / mL to 15-25 mg / mL; the richer variety of phytochemicals (including newly added fat-soluble carotenoids) and higher concentration provide more abundant natural metabolic regulators for the targeted fermentation of metabolic precursors, which can increase the yield of γ-aminobutyric acid by 50%-100% on the original basis, forming a positive amplification cycle of "extraction and fermentation".

[0108] Experiment 1: Verification Experiment of Multistage Countercurrent Extraction and Phytochemical Enrichment Efficiency

[0109] (I) Experimental Objective

[0110] The invention's "three-stage countercurrent extraction, food-grade solubilizer, three-stage membrane separation, and closed-loop recycling of extraction residue" technical solution demonstrates improvements in phytochemical extraction rate and total phenol content compared to (single-stage countercurrent extraction + pure water + single-stage nanofiltration).

[0111] (II) Experimental Standards

[0112] Total phenol content GB / T 8313-2018 "Determination of the content of tea polyphenols and catechins in tea" (Folin-Ciocalteu method principle) Quantitative analysis using 760nm colorimetric method Glucosinoside ISO 9167-1:1992 "Determination of glucosinolate content in rapeseed" High performance liquid chromatography Carotenoids GB / T 41133-2021 Determination of Lycopene, Lutein, etc. in Tomato Products High performance liquid chromatography

[0113] (III) Experimental Grouping

[0114] Group A (Example 2) Single-stage countercurrent extraction, pure water and single-stage nanofiltration Group B (Example 4) Three-stage countercurrent extraction, pure water + 10% ethanol, microfiltration, ultrafiltration, nanofiltration, and closed-loop recycling of permeate. Group C (control group) The process is identical to Example 2, except for the absence of countercurrent extraction and single-stage nanofiltration.

[0115] (iv) Experimental methods

[0116] Sample preparation: 100 kg of vegetable peel, chopped vegetables and vegetable tips generated during the cutting process of pickled mustard tuber were collected. After sorting and impurity removal and microwave pretreatment (2450 MHz, 60 seconds), the samples were extracted according to the schemes of Group A and Group B respectively.

[0117] Group A (Example 2 or Example 3): Single-stage countercurrent extraction: feed-to-liquid ratio 1:10, 6°C cold water, extraction for 60 minutes, ultrasonic treatment at 28 kHz, 0.5 W / cm². 2 Nanofiltration concentration: molecular weight cutoff 200 Da, operating pressure 1.0 MPa;

[0118] Group B (Example 4):

[0119] Three-stage countercurrent extraction: first stage: material-to-liquid ratio 1:6, extraction time 30 minutes; second stage: material-to-liquid ratio 1:5, extraction time 20 minutes; third stage: material-to-liquid ratio 1:4, extraction time 15 minutes; extraction solvent: 6℃ cold water + 10% food-grade ethanol;

[0120] Three-stage membrane separation: ceramic microfiltration (0.2μm) → ultrafiltration (molecular weight cutoff 8kDa) → nanofiltration (molecular weight cutoff 200Da);

[0121] All nanofiltration permeate is reused in the next extraction batch.

[0122] Group C (control group): No countercurrent extraction and single-stage nanofiltration were performed; otherwise, it was the same as in Example 2.

[0123] Three parallel samples were used in each group, and the mean ± standard deviation was taken.

[0124] V. Experimental Results (See Table 1 for details)

[0125] Table 1

[0126] Total phenol extraction rate (%) 69.2 96.3 20.1 Total phenol content (mg / mL concentrate) 2.9 23.1 0.51 Glucosinoside extraction rate (%) 62.3 93.8 8.9 Carotenoid extraction rate (%) 8.5 86.2 2.3 Extraction water consumption (L / batch) 1000 220 - Nanofiltration membrane cleaning cycle (days) 7 35 -

[0127] Through Table 1 and Figure 1 It can be known that:

[0128] The extraction rate of carotenoids increased from 8.5% to 86.2%. Pure water extraction is almost unable to extract fat-soluble carotenoids. In Example 4, the introduction of food-grade ethanol as a solubilizer enabled this part of phytochemicals to be "created from nothing", which is equivalent to obtaining a completely new type of functional component.

[0129] The total phenol content increased from 2.8 mg / mL to 22.6 mg / mL; the combined effect of three-stage countercurrent extraction, solubilization, and membrane purification far exceeded the expectations of simple addition.

[0130] The cleaning cycle of nanofiltration membranes has been extended from 7 days to 35 days; the pretreatment combination of microfiltration and ultrafiltration effectively removes suspended solids and macromolecular colloids, significantly reducing the fouling rate of nanofiltration membranes.

[0131] The extraction water consumption was reduced by 78%, achieving the environmental goal of near-zero emissions.

[0132] Experiment 2: Selective Antibacterial Experiment with ε-Polylysine

[0133] (I) Experimental Objective

[0134] To verify the selective inhibitory effect of ε-polylysine on miscellaneous bacteria (Gram-negative bacteria) in the fermentation system, and its low inhibitory effect on target bacteria (Gram-positive bacteria such as lactic acid bacteria).

[0135] (II) Experimental Standards

[0136] Total bacterial count determination GB 4789.2-2022 National Food Safety Standard - Microbiological Examination of Food: Determination of Total Colony Count Plate counting method Coliform count GB 4789.3 National Food Safety Standard: Microbiological Examination of Food - Coliform Count MPN counting method Lactic acid bacteria count GB 4789.35-2023 National Food Safety Standard: Microbiological Examination of Food - Examination of Lactic Acid Bacteria Selective counting in MRS medium

[0137] (III) Experimental Grouping

[0138] Group D (control group) Enzymatic hydrolysate, lactic acid bacteria, Candida utilis and Bacillus subtilis 0 Group E (Example 2 or Example 3) Enzymatic hydrolysate, lactic acid bacteria, Candida utilis and Bacillus subtilis 0.05%

[0139] (iv) Experimental methods

[0140] 1. The fermentation system was prepared according to Example 2 or Example 3. Group D did not add ε-polylysine, while Group E added 0.05% ε-polylysine (molecular weight 4000 Da, purity 96%).

[0141] 2. Anaerobic fermentation at 35℃ for 18 hours (first stage)

[0142] 3. After fermentation is complete, samples are taken for further analysis:

[0143] Plate count method for determining total colony count (GB 4789.2-2022);

[0144] MPN counting method for coliform bacteria (GB 4789.3);

[0145] Selective counting of lactic acid bacteria on MRS medium (GB 4789.35-2023).

[0146] Three parallel samples were taken in each group, and the mean ± standard deviation was used.

[0147] (v) Experimental results (see Table 2 for details)

[0148] Table 2

[0149] Total bacterial count (CFU / mL) <![CDATA[8.6×10 7 ]]> <![CDATA[2.1×10 7 ]]> 75.6 Coliform bacteria (MPN / 100mL) <![CDATA[4.5×10 4 ]]> <![CDATA[8.2×10 3 ]]> 81.8 Lactic acid bacteria count <![CDATA[3.2×10 7 ]]> <![CDATA[3.0×10 7 ]]> 6.3

[0150] Table 2 shows that:

[0151] ε-Polylysine exhibited an 81.8% inhibition rate against coliform bacteria (Gram-negative bacteria), while its inhibition rate against lactic acid bacteria (Gram-positive bacteria) was only 6.3%. This selective inhibition ratio of 13:1 achieved precise antibacterial control, effectively suppressing contamination by other microorganisms without affecting the target fermentation bacteria.

[0152] The polycationic properties of ε-polylysine preferentially bind to the lipopolysaccharide of the outer membrane of Gram-negative bacteria, disrupting the membrane integrity; while Gram-positive bacteria have a thicker peptidoglycan layer and are less sensitive to ε-polylysine. This selective antimicrobial effect significantly reduces the contamination rate of the fermentation system of this invention from 10%-30% in the prior art to below 5%.

[0153] Experiment 3: Synergistic Antioxidant Experiment of Astaxanthin-Active Peptides-Tea Polyphenols

[0154] (I) Experimental Objective

[0155] To verify whether the combined use of astaxanthin, active peptides, and tea polyphenols produces a synergistic antioxidant effect.

[0156] (II) Experimental Standards

[0157] DPPH free radical scavenging rate GB / T 27500-2011 Determination of DPPH Free Radical Scavenging Rate of Antioxidants Scavenging efficiency was measured at a wavelength of 517 nm. Total antioxidant capacity ISO 16348:2013 Determination of total antioxidant activity in vitro ABTS method for determining Trolox equivalent at 734 nm

[0158] (III) Experimental Grouping

[0159] Group F (control group) Active peptide liquid (free of astaxanthin and tea polyphenols) The active peptide solution obtained in Example 2 or 3 Group G (control group) Active peptide solution and tea polyphenols (0.3%) Astaxanthin-free Group H (control group) Active peptide solution and astaxanthin (0.15%) Astaxanthin-free Group I (This Invention) Active peptide solution, astaxanthin (0.15%), and tea polyphenols (0.3%) Ternary co-spray dried product of Example 2 or 3

[0160] (iv) Experimental methods

[0161] DPPH free radical scavenging rate determination (refer to GB / T 27500-2011):

[0162] 1. Prepare a 0.1 mmol / L DPPH free radical solution (prepared with anhydrous ethanol).

[0163] 2. Mix 2 mL of DPPH solution with 2 mL of sample solution and react in the dark for 30 minutes;

[0164] 3. Measure the absorbance at a wavelength of 517 nm;

[0165] 4. Sweep rate calculation formula: Sweep rate (%) = [1 - (A)] 样品 -A 空白 ) / A 对照 ]×100%

[0166] 5. Three parallel samples were measured for each group, and the mean ± standard deviation was taken.

[0167] Determination of total antioxidant capacity of ABTS (refer to ISO 16348:2013):

[0168] 1. Prepare ABTS + Free radical working solution;

[0169] 2. Samples and ABTS + The working solution reacts for 6 minutes;

[0170] 3. Measure the absorbance at 734 nm and express it as Trolox equivalent;

[0171] (v) Experimental results (see Table 3 for details)

[0172] Table 3

[0173] DPPH clearance rate (%) 58.3 72.6 68.4 92.7 ABTS (μmol TE / g) 325 452 418 589

[0174] Through Table 3 and Figures 2-4 It can be known that:

[0175] Theoretical superposition value (Group G + Group H - Group F): 72.6 + 68.4 - 58.3 = 82.7%

[0176] Group I measured value: 92.7%

[0177] Synergistic effect: 92.7% - 82.7% = 10.0 percentage points

[0178] Synergistic improvement rate: (92.7-82.7) / 82.7×100%=12.1%

[0179] Astaxanthin (a super free radical scavenger with more than 10 times the activity of tea polyphenols), tea polyphenols (phenolic hydroxyl donors), and active peptides (metal chelating ability) form a triple antioxidant network of "free radical scavenging - phenolic hydroxyl regeneration - metal ion chelation", which produces a synergistic effect of 12.1% greater than simple superposition.

[0180] Experiment 4: Astaxanthin-β-cyclodextrin inclusion complex spray drying protective effect experiment

[0181] (I) Experimental Objective

[0182] To verify the protective effect of β-cyclodextrin inclusion of astaxanthin during the high-temperature spray drying process.

[0183] (II) Experimental Standards

[0184] Astaxanthin content GB / T 31520-2015 Determination of Astaxanthin in Haematococcus pluvialis by Liquid Chromatography High performance liquid chromatography

[0185] (III) Experimental Grouping

[0186] Group J Active peptide solution + astaxanthin (0.15%), without high-pressure homogenization. No encapsulation protection Group K (This invention) Active peptide solution + astaxanthin (0.15%) + β-cyclodextrin (1%), homogenized under high pressure (80MPa, 3 times). β-Cyclodextrin inclusion protection

[0187] (iv) Experimental methods

[0188] 1. Prepare the spray drying pretreatment solution according to the J and K group schemes respectively;

[0189] 2. Spray drying conditions: air inlet 180℃, air outlet 80℃;

[0190] 3. Samples were taken before and after spray drying, and the astaxanthin content was determined according to GB / T 31520-2015 "Determination of Astaxanthin in Haematococcus pluvialis by Liquid Chromatography".

[0191] 4. Astaxanthin retention rate = (Astaxanthin content after spray drying / Astaxanthin content before spray drying) × 100%;

[0192] 5. Three parallel samples were used in each group, and the mean ± standard deviation was taken.

[0193] (v) Experimental results (see Table 4 for details)

[0194] Table 4

[0195] Astaxanthin content (%) before spraying 0.15 0.15 Astaxanthin content after spraying (%) 0.062 0.138 Astaxanthin retention rate (%) 41.3 92.0

[0196] Table 4 shows that:

[0197] Astaxanthin molecules possess a long-chain conjugated double bond structure, making them extremely sensitive to light, heat, and oxygen. This invention utilizes high-pressure homogenization to encapsulate astaxanthin within the hydrophobic cavities of β-cyclodextrin, increasing the astaxanthin retention rate during spray drying from 41.3% to 92.0%. This protective effect far exceeds the expectations of simply combining β-cyclodextrin or high-pressure homogenization alone.

[0198] Experiment 5: Comparison of Overall Product Performance

[0199] (I) Experimental Objective

[0200] A comprehensive comparison of the product of this invention with existing technologies was conducted to verify the overall superiority of each indicator.

[0201] (II) Summary of Experimental Standards

[0202] crude protein GB / T 6432-2018 Determination of crude protein in feed using the Kjeldahl method crude fiber GB / T 6434-2006 Determination of crude fiber content in feed by filtration method Small molecule peptides T / ZJBX10-2021 Determination of the proportion of protein hydrolysates with a relative molecular weight of less than 1000u in protein feed ingredients Astaxanthin GB / T 31520-2015 Determination of Astaxanthin in Haematococcus pluvialis by Liquid Chromatography GABA GB / T 47209-2026 Determination of γ-aminobutyric acid in grains by high performance liquid chromatography (HPLC) in grain and oil testing xylooligosaccharides GB / T 23747-2009 xylooligosaccharide feed additive Digestibility GB / T 17811-2008 Determination of pepsin digestibility of animal protein feed by filtration method DPPH removal rate GB / T 27500-2011 Determination of DPPH free radical scavenging rate of antioxidants

[0203] (III) Experimental Samples

[0204] Comparative sample: Pickled mustard tuber peel feed prepared according to the prior art (CN104920797A, a pickled mustard tuber peel dietary fiber feed and its preparation method);

[0205] Samples of the present invention: compound feed additives and extruded feed pellets prepared according to Example 2 or 3.

[0206] (iv) Experimental methods

[0207] Crude protein determination (refer to GB / T 6432-2018): Kjeldahl method was used. The crude protein content was calculated after the sample was digested with sulfuric acid, distilled, and titrated.

[0208] Crude fiber determination (refer to GB / T 6434-2006): The filtration method is used. After the sample is treated with dilute acid and dilute alkali, it is filtered, ignited, weighed, and the crude fiber content is calculated.

[0209] Determination of small molecule peptides (refer to T / ZJBX10-2021): The proportion of peptides with a molecular weight of less than 1000u in the total protein was determined by high-performance gel filtration chromatography.

[0210] Astaxanthin determination (refer to GB / T 31520-2015): High performance liquid chromatography (HPLC) was used. After extraction and purification, the astaxanthin content of the sample was determined at a specific wavelength.

[0211] GABA determination (refer to GB / T 47209-2026): High performance liquid chromatography (HPLC) was used. After extraction and derivatization, the GABA content of the sample was determined at a specific wavelength.

[0212] Determination of xylooligosaccharide content (refer to GB / T 23747-2009): The xylooligosaccharide content was determined by high performance liquid chromatography.

[0213] Pepsin digestibility determination (refer to GB / T 17811-2008): After the sample is digested with pepsin, it is filtered, the undigested residue is measured, and the digestibility is calculated.

[0214] DPPH radical scavenging efficiency determination (refer to GB / T 27500-2011): DPPH radical scavenging efficiency was determined at a wavelength of 517 nm.

[0215] (v) Experimental results (see Table 5 for details)

[0216] Table 5

[0217] Crude protein (%) 16.5 46.1 24.2 GB / T 6432-2018 Crude fiber (%) 18.6 2.5 6.8 GB / T 6434-2006 Small molecule peptides (less than 1000u, %) - 68.2 - T / ZJBX10-2021 Astaxanthin (%) - 0.28 - GB / T 31520-2015 GABA (mg / g) - 3.8 - GB / T 47209-2026 xylooligosaccharides (%) - - 0.8 GB / T 23747-2009 Pepsin digestibility (%) 52.3 - 91.2 GB / T 17811-2008 DPPH clearance rate (%) 15.2 92.7 48.3 GB / T 27500-2011

[0218] Table 5 shows that:

[0219] 1. Crude protein content: The compound additive of this invention (46.1%) is 179% higher than that of the comparative example (16.5%), mainly due to the single-cell protein synthesis of Candida utilis and the deep degradation of protein by Bacillus subtilis.

[0220] 2. Crude fiber content: The compound additive of this invention (2.5%) is 86.6% lower than that of the comparative example (18.6%). The triple action of ultra-fine grinding, compound enzymatic hydrolysis and multi-strain stepwise fermentation degrades anti-nutritional factors.

[0221] 3. Digestibility: The puffed granules of this invention (91.2%) are 74.4% higher than those of the comparative example (52.3%). The high temperature and high pressure treatment of xylooligosaccharide-puffed granulation makes the starch gelatinization degree reach more than 85%, which improves the digestibility and absorption rate.

[0222] 4. Antioxidant activity: The DPPH scavenging rate of the compound additive of this invention (92.7%) is 510% higher than that of the comparative sample (15.2%), and the triple synergistic antioxidant network of astaxanthin-tea polyphenols-active peptides plays a key role.

[0223] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for recycling and reusing vegetable scraps during the cutting of pickled vegetables, characterized in that, Includes the following steps: Step 1: Collect the vegetable residue generated during the cutting of pickled vegetables and pre-treat it with microwave. After that, perform cold water countercurrent extraction and phytochemical enrichment to obtain phytochemical concentrate and extracted vegetable residue. Then, perform gradient desalination and high-salt wastewater membrane distillation on the extracted vegetable residue, followed by low-temperature ultrafine grinding and compound enzymatic hydrolysis. Step 2: Directed fermentation and selective inhibition of metabolic precursors Adjust the pH of the enzymatic hydrolysate from step one to 5.5-6.5, add phytochemical concentrate, L-glutamic acid and ε-polylysine, first inoculate with lactic acid bacteria for anaerobic fermentation, then inoculate with Candida utilis for aerobic fermentation, and finally inoculate with Bacillus subtilis for secondary aerobic fermentation. Step 3: Membrane separation and fractionation to obtain supernatant and precipitate. The supernatant is then separated by ultrafiltration membrane to obtain active peptide solution and retentate. Step 4: Spray drying of astaxanthin, active peptides, and tea polyphenols. Add 0.5%-2% β-cyclodextrin, 0.05%-0.3% Haematococcus pluvialis extract and 0.1%-0.5% tea polyphenols to the active peptide solution, and spray dry it with an inlet air temperature of 160-200℃ and an outlet air temperature of 70-90℃ to obtain a compound feed additive rich in small molecule active peptides, astaxanthin and tea polyphenols. Step 5: Xylooligosaccharide-expanded feed pelleting.

2. The process for recycling and reusing vegetable residue during the cutting of pickled vegetables according to claim 1, characterized in that, Step one includes the following steps: S1. Collect vegetable scraps generated during the cutting of pickled vegetables. After sorting and removing impurities, pre-treat the vegetable scraps with microwave at a frequency of 2450MHz for 30-120 seconds. S2, Cold Water Countercurrent Extraction and Phytochemical Enrichment The microwave-pretreated vegetable residue was subjected to countercurrent extraction in cold water at 4-10℃ for 30-120 minutes. The extract was then concentrated using a nanofiltration membrane to obtain a phytochemical concentrate and the extracted vegetable residue. The material-to-liquid ratio for countercurrent extraction was 1:5-1:

15. Ultrasonic-assisted extraction was used during the process, with an ultrasonic frequency of 20-40 kHz and a power density of 0.2-1 W / cm³. 2 The molecular weight cutoff of nanofiltration membranes is 150-300 Da, and the operating pressure is 0.5-1.5 MPa.

3. The process for recycling and reusing vegetable scraps during the cutting of pickled vegetables according to claim 2, characterized in that, Step one also includes the following steps: S1, gradient desalination The extracted vegetable residue was placed in a first desalination tank and a second desalination tank for two-stage gradient soaking and desalination. The mass concentration of brine in the first desalination tank was 3%-5%, and the mass concentration of brine in the second desalination tank was 0.5%-1.5%. The soaking times were 2-4 hours and 1-2 hours, respectively. After desalination, the salt content of the vegetable residue was reduced to below 1.5%. S2, High-salt wastewater membrane distillation treatment: The desalination wastewater generated during gradient desalination is collected and concentrated by membrane distillation to obtain crystalline salt and mineral-phytochemical concentrate. The membrane distillation uses a polytetrafluoroethylene hollow fiber membrane with a pore size of 0.1-0.5 μm, an operating temperature of 50-70℃, and a vacuum degree of 0.05-0.1 MPa.

4. The process for recycling and reusing vegetable scraps during the cutting of pickled vegetables according to claim 3, characterized in that, Step one also includes the following steps: S1, Low-temperature ultrafine grinding The desalted vegetable residue was ultra-finely pulverized at a low temperature of -10℃ to -20℃ until it was pulverized into ultra-fine powder with a particle size of 10-50μm. S2, compound enzymatic hydrolysis Ultrafine powder and water are mixed at a mass ratio of 1:3 to 1:5, and a compound enzyme preparation is added for enzymatic hydrolysis. The compound enzyme preparation consists of cellulase, hemicellulase, pectinase, and neutral protease in a mass ratio of 2:1:1:1, with an addition amount of 0.5%-2% of the ultrafine powder mass. The enzymatic hydrolysis temperature is 45-55℃, and the hydrolysis time is 2-6 hours. After hydrolysis, the enzyme is inactivated. Ultrasonic assisted hydrolysis is used during the process, with an ultrasonic frequency of 20-40 kHz and a power density of 0.5-2 W / cm³. 2 .

5. The process for recycling and reusing vegetable scraps during the cutting of pickled vegetables according to claim 1, characterized in that, The second step, the directed fermentation and selective inhibition of metabolic precursors, includes the following steps: adjusting the pH of the enzymatic hydrolysate from the first step to 5.5-6.5, adding phytochemical concentrate, L-glutamic acid, and ε-polylysine; first, inoculating with lactic acid bacteria for anaerobic fermentation at 30-37℃ for 12-24 hours; then inoculating with Candida utilis for aerobic fermentation at 28-32℃ for 8-16 hours; finally, inoculating with Bacillus subtilis for secondary aerobic fermentation at 35-40℃ for 6-12 hours; wherein the amount of phytochemical concentrate added is 1%-5% of the enzymatic hydrolysate volume, the amount of L-glutamic acid added is 0.5%-2% of the enzymatic hydrolysate mass, and the amount of ε-polylysine added is 0.01%-0.1% of the enzymatic hydrolysate mass.

6. The process for recycling and reusing vegetable residue during the cutting of pickled vegetables according to claim 1, characterized in that, The ε-polylysine has a molecular weight of 3500-4500 Da, a degree of polymerization of 25-35, and a purity of not less than 95%; the lactic acid bacteria are a mixture of Lactobacillus plantarum and Lactobacillus acidophilus, with an inoculation ratio of 1:1 and an inoculation amount of 2%-5% of the enzymatic hydrolysate volume; the inoculation amount of Candida utilis is 1%-3% of the enzymatic hydrolysate volume; and the inoculation amount of Bacillus subtilis is 1%-3% of the enzymatic hydrolysate volume.

7. The process for recycling and reusing vegetable residue during the cutting of pickled vegetables according to claim 1, characterized in that, The membrane separation and fractionation in step three includes the following steps: centrifuging the fermented material to obtain supernatant and precipitate, and then separating the supernatant through an ultrafiltration membrane to obtain an active peptide solution with a molecular weight less than 10 kDa and a retentate solution with a molecular weight greater than 10 kDa; wherein, the ultrafiltration membrane is a polyethersulfone hollow fiber ultrafiltration membrane with a molecular weight cutoff of 10 kDa and an operating pressure of 0.1-0.3 MPa.

8. The process for recycling and reusing vegetable scraps during the cutting of pickled vegetables according to claim 1, characterized in that, In step four, the astaxanthin content in the Haematococcus pluvialis extract is 3%-8%; the tea polyphenols are from green tea extract, in which the content of epigallocatechin gallate is not less than 50%.

9. The process for recycling and reusing vegetable residue during the cutting of pickled vegetables according to claim 1, characterized in that, In step four, β-cyclodextrin, Haematococcus pluvialis extract, and tea polyphenols are subjected to high-pressure homogenization before spray drying to form nano-inclusion complexes. The homogenization pressure is 50-100 MPa, and the homogenization is performed 2-4 times.

10. The process for recycling and reusing vegetable residue during the cutting of pickled vegetables according to claim 1, characterized in that, The fifth step of the xylooligosaccharide-expanded feed granulation includes the following steps: mixing the precipitate obtained in the third step with the retentate obtained in the fourth step, adding xylooligosaccharide at a mass of 0.5%-2% of the mixture, adjusting the moisture content to 25%-35%, and feeding it into a twin-screw extruder for extrusion and expansion. The expansion temperature is 120-160℃, the screw speed is 200-400 rpm, and after expansion, the pellets are cut and dried to obtain xylooligosaccharide-containing extruded feed pellets.

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