A method for optimizing a high-efficiency crushing process with high retention of desert algae actives

Abstract

This invention discloses an optimized method for a highly efficient fragmentation process of desert algae with high retention of active ingredients. The invention uses cell disruption rate, chlorophyll retention rate, and polysaccharide retention rate as core evaluation indicators, focusing on key parameters of the high-pressure homogenization fragmentation process (fracture pressure, fragmentation time, and algal liquor mass fraction). Effective ranges for these parameters are screened through single-factor experiments, and a multivariate synergistic regression model is constructed using response surface methodology to accurately predict the fragmentation effect and the retention rate of active ingredients. Experimental verification shows that the model has excellent fit; under optimal process conditions, the desert algae fragmentation rate is ≥91.5%, the chlorophyll retention rate is ≥76.9%, and the polysaccharide retention rate is ≥72.4%, significantly superior to existing ultrasonic fragmentation and enzymatic hydrolysis processes. This invention has advantages such as simple operation, high fragmentation efficiency, minimal loss of chlorophyll and polysaccharides, and high accuracy in predicting results. The fragmented products can be directly used in the development of desert algae fertilizers and other products, providing key technical support for the efficient industrial utilization of desert algae resources.

Description

Technical Field

[0001] This invention belongs to the field of desert algae resource development and utilization technology, specifically involving an optimized method for a high-efficiency crushing process that retains a high level of active ingredients in desert algae. It focuses on solving the problem of synergistic regulation between crushing efficiency and retention rate of active ingredients, providing technical support for the industrial application of desert algae in agriculture, food, and medicine. Background Technology

[0002] Desert algae are a special microalgal community that grows in extremely arid environments such as deserts and wastelands. They possess excellent characteristics such as drought resistance (due to intracellular polysaccharide accumulation), high temperature resistance, and UV resistance. Their cells are rich in active ingredients such as polysaccharides, amino acids, chlorophyll, and trace elements, which have broad application prospects in agriculture, food, and medicine. Among them, polysaccharides can improve soil water holding capacity (adding 0.5% algal polysaccharides can increase the water holding capacity of sandy soil by 30%) and improve soil structure (reducing soil bulk density by 0.1-0.2 g / cm³). 3 Chlorophyll can enhance plant photosynthetic efficiency (increasing the photosynthetic rate by 15%-20%), and together with plant polysaccharides, the two synergistically promote crop growth, which is crucial for the subsequent preparation of desert algae fertilizer. Furthermore, desert algae polysaccharides also possess antioxidant activity (DPPH free radical scavenging rate ≥60%), making them suitable as a natural food additive; chlorophyll derivatives have anti-inflammatory and antibacterial effects and can be used to prepare topical dressings.

[0003] To achieve efficient utilization of the active ingredients in desert algae, the core issue is to efficiently break down the thick and tough cell walls of desert algae (which are 2-3 times thicker than those of ordinary microalgae, while retaining more intracellular active substances). However, existing disruption technologies, such as the combined alkali solution and ultrasonic disruption method (invention patent CN202511078211.1), require continuous processing for 6-8 hours to achieve a moderate disruption rate (20%-30%). Moreover, the concentrated ultrasonic energy can easily lead to a sudden increase in local temperature (up to 50°C or higher). Since the chlorophyll and polysaccharides are temperature-sensitive and unstable, their retention rate will be less than 50%. The enzymatic hydrolysis method (invention patent CN202510981546.8) takes 12-24 hours, and the enzyme preparation is expensive (enzyme cost ≥ 500 yuan per ton of algal solution). The subsequent enzyme purification steps are cumbersome and difficult to scale up industrially. The traditional high-pressure homogenization method (invention patent CN201510219035.9) is mostly for microalgae with thin cell walls. It does not take into account the structural characteristics of desert algae cell walls and directly applies disruption conditions, resulting in "insufficient disruption" or "loss of active ingredients".

[0004] Existing crushing technologies suffer from limitations in achieving both efficient crushing of desert algae and preservation of active ingredients, and lack a correlation model between parameters and effects, hindering precise control of the crushing process. Therefore, there is an urgent need to develop a targeted, optimized crushing process and predictive model to address these shortcomings and lay a scientific foundation for adapting to large-scale industrial production. Summary of the Invention

[0005] To address the problems of low fragmentation efficiency, low chlorophyll and polysaccharide retention rates, and lack of accurate predictive models in existing technologies for desert algae, this invention aims to provide an optimized method for a highly efficient fragmentation process that retains a high level of active ingredients in desert algae. This method achieves the synergistic goal of "high fragmentation rate - high activity retention - industrial adaptability," overcoming the challenges of fragmentation due to the thick and tough cell walls of desert algae, as well as the technical bottlenecks of temperature sensitivity and easy decomposition of intracellular polysaccharides, chlorophyll, and other active ingredients.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides an optimized method for a highly efficient fragmentation process that retains a high concentration of active substances from desert algae, comprising the following steps: (1) Screening of characteristic parameters and single-factor experiments: The core characteristic parameters of the high-pressure homogenization method for breaking desert algae were screened: breaking pressure, breaking time and algal liquid mass fraction. Single-factor variable experiments were conducted to investigate the independent influence of each characteristic parameter on the breaking rate, chlorophyll retention rate and polysaccharide retention rate. (2) Response surface experimental design and data acquisition: Based on the effective range of parameters determined by the single-factor variable experiment in step (1), the response surface method was adopted, with the crushing pressure, crushing time and algal liquid mass fraction as input variables, and the crushing rate, chlorophyll and polysaccharide retention rate as response variables to design an experimental scheme and obtain statistically significant response surface design experimental data. (3) Construction of regression equation model: Based on the response surface design experimental data obtained in step (2), establish regression equation model, which includes the breakage rate regression equation Y1, the chlorophyll retention rate regression equation Y2, and the polysaccharide retention rate regression equation Y3. (4) Model verification and optimal process determination: The accuracy of the regression equation model obtained in step (3) is verified by experiments. The optimal crushing conditions predicted by the model are selected to meet the preset targets of crushing rate ≥90%, chlorophyll retention rate ≥70%, and polysaccharide retention rate ≥70%.

[0008] Based on the above technical solution, further, the desert algae mentioned in step (1) is from the genera Nostoc, Chlamydomonas, or Chlorella.

[0009] Based on the above technical solution, further, the crushing pressure in step (1) is 1000~1500 bar, the crushing time is 3~18 min, the algal liquid mass fraction is 2~10%, and the crushing temperature is 1~10℃.

[0010] Based on the above technical solution, further, after high-pressure homogenization and crushing in step (1), the crushing rate is determined by direct microscopic counting method, the chlorophyll retention rate is determined by acetone-ethanol (volume ratio 1:1) extraction method combined with absorbance at 645 nm and 663 nm, and the polysaccharide retention rate is determined by DNS method combined with absorbance at 540 nm and glucose standard curve (regression equation y=1.25049x+0.05092, R²=0.9992).

[0011] Based on the above technical solution, the key steps of the response surface experimental design in step (2) are as follows: select the optimal range of values ​​for each characteristic parameter according to the experimental results of the single-factor variables of each characteristic parameter, then take each characteristic parameter as the input variable and take the breakage rate, chlorophyll and polysaccharide retention rate as the response variables to conduct the experiment, and finally perform model fitting.

[0012] Based on the above technical solution, further, the regression equation model described in step (3) has R²≥0.97, p≤0.0001, and lack-fit term p≥0.05.

[0013] Based on the above technical solution, further, the regression equation model in step (3) simultaneously correlates the variable parameters with the breakage rate, chlorophyll retention rate, and polysaccharide retention rate, specifically as follows: Regression equation for breakage rate: Y1= 65.98 + 25.86A + 5.75B - 5.04C - 1.9A×B - 2.39A×C - 0.355B×C -5.39A 2 + 1.16B 2 - 0.7209C 2 (R) 2 =0.9986); The regression equation for chlorophyll retention rate is: Y2= 82.77 - 6.33A - 3.38B + 1.01C - 1.03A×B - 0.9062A×C + 1.80B×C- 0.4786A 2 + 0.8064B 2 + 3.62C 2 (R) 2 =0.9845); Regression equation for polysaccharide retention rate: Y3= 71.89 - 4.36A - 3.74B + 3.48C + 0.1425A×B - 1.13A×C - 0.4525B×C + 10.43A 2 - 1.15B 2 - 2.61C 2 - 3.66A 2 C(R) 2 =0.9751); Where A is the crushing pressure (bar), B is the crushing time (min), and C is the mass fraction of the added algal solution (%). The p-value of the model is <0.0001, and the p-value of the lack-of-fit term is >0.05.

[0014] Based on the above technical solution, further, the optimal crushing conditions described in step (4) can take into account high crushing rate, chlorophyll and polysaccharide retention rate, crushing pressure 1486~1490 bar, crushing time 11 min, algal liquid mass fraction 3%, crushing rate ≥91.5%, chlorophyll retention rate ≥76.9%, and polysaccharide retention rate ≥72.4%.

[0015] Secondly, the present invention provides a highly efficient crushing process for highly retaining active substances from desert algae, comprising the following steps: At 1~10℃, a desert algae suspension with a mass fraction of 2~4% was added to the hopper of a high-pressure homogenizer. The crushing pressure was set to 1480~1490 bar and the crushing time was 10~12 min for pressure crushing to obtain a crushed product with high retention of desert algae active substances.

[0016] Based on the above technical solution, the desert algae is further defined as belonging to the genera *Nostoc*, *Chlamydomonas*, or *Chlorella*.

[0017] Based on the above technical solution, the Chlorella genus further includes Chlorella sorokin.

[0018] Based on the above technical solution, the crushing pressure is 1485~1490 bar, the crushing time is 11 min, and the mass fraction of the desert algae suspension is 3%.

[0019] Based on the above technical solution, furthermore, the solvent for the desert algae suspension is water.

[0020] Based on the above technical solution, further, the breakage rate is ≥90%, the chlorophyll retention rate is ≥70%, and the polysaccharide retention rate is ≥70%.

[0021] Compared with the prior art, the present invention has the following beneficial effects: This invention optimizes the parameters for high-pressure homogenization and crushing, addressing the characteristics of thick and tough desert algae cell walls. It solves the problems of low crushing efficiency, long processing time, and low chlorophyll and polysaccharide retention rates in traditional processes (such as ultrasonic crushing). The optimized parameter range conforms to the conventional operating range of industrial-grade high-pressure homogenizers. The constructed model can predict actual results. Verification shows that under optimal conditions, it can achieve a crushing rate ≥90% and a chlorophyll and polysaccharide retention rate ≥70%, with short processing time and excellent results. It reconciles the contradiction between crushing rate and active ingredient retention rate, making it suitable for large-scale production. The crushed product can be directly used in the development of desert algae fertilizers and other products, providing key technical support for the efficient industrial utilization of desert algae resources. Attached Figure Description

[0022] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0023] Figure 1 This is a standard curve of glucose absorbance versus concentration.

[0024] Figure 2 The figure shows the results of a single-factor analysis of the effects of crushing pressure on the crushing rate (a), chlorophyll retention rate (b), and polysaccharide retention rate (c) when the crushing time is 6 min and the mass fraction of algal solution is 6%.

[0025] Figure 3 The figure shows the results of a univariate analysis of the effects of crushing time on the crushing rate (a), chlorophyll retention rate (b), and polysaccharide retention rate (c) when the crushing pressure is 1400 bar and the mass fraction of added algae solution is 6%.

[0026] Figure 4 The figure shows the results of a univariate analysis of the effects of the mass fraction of algal solution on the breakup rate (a), chlorophyll retention rate (b), and polysaccharide retention rate (c) when the breakup pressure is 1400 bar and the breakup time is 6 min.

[0027] Figure 5 The response surface plots show the effects of crushing pressure A and crushing time B (a), the mass fraction of algae solution C, crushing pressure A (b), the mass fraction of algae solution C, and crushing time B (c) on the crushing rate.

[0028] Figure 6 The response surface graphs show the effects of crushing pressure A and crushing time B (a), the mass fraction of algal solution C, crushing pressure A (b), the mass fraction of algal solution C, and crushing time B (c) on chlorophyll retention.

[0029] Figure 7The response surface methodology plots show the effects of crushing pressure A and crushing time B (a), the mass fraction of algal solution C, crushing pressure A (b), the mass fraction of algal solution C, and crushing time B (c) on polysaccharide retention.

[0030] Figure 8 A schematic diagram explaining why different mass fractions of added algae solution affect the crushing effect.

[0031] Figure 9 Microscopic images of desert algae cells before (a) and after (b) disruption using the high-pressure homogenization method of this invention. Detailed Implementation

[0032] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0033] 1. Evaluation of Disruption Effect: Before and after disruption, aspirate algal solution onto a slide of an optical microscope using a pipette. Rotate the objective lens until the algae are clearly visible in the field of view, then observe and count them. During this process, change the observation area and select 5 areas to obtain the total number of intact cells before disruption and the total number of intact cells after disruption. Calculate the disruption rate using the formula: Disruption Rate = (Total number of intact cells before disruption - Total number of intact cells after disruption) / Total number of intact cells before disruption × 100%.

[0034] 2. Evaluation of chlorophyll retention rate: The acetone-ethanol extraction method was used. 10 mL of live algae solution (V mL) and 10 mL of the corresponding broken algae solution were weighed and added to 10 mL of extraction solution (acetone:ethanol = 1:1). The mixtures were then placed in a constant-temperature shaker (30℃, 16 h) in the dark. After centrifugation (12000 rpm, 10 min), the absorbance values ​​(A) of chlorophyll a and chlorophyll b at wavelengths of 645 nm and 663 nm were measured. The retention rates of chlorophyll a, chlorophyll b, and total chlorophyll were calculated using the following formulas: Chlorophyll a (mg / mL) = (12.71) A 663 -2.59 A 645 ) / 1000; Chlorophyll b (mg / mL) = (22.88) A 645 -4.67 A 663 ) / 1000; Total chlorophyll (mg) = (chlorophyll a + chlorophyll b) 2 V; Chlorophyll retention rate (%) = Chlorophyll content of the broken group / Chlorophyll content of the live algae group 100%; 3. Evaluation of polysaccharide retention rate: Plotting the standard curve Using glucose as a standard, a series of glucose solutions with concentrations (0.0~1.0 mg / mL) were prepared. The absorbance was measured using the DNS method, and an absorbance-concentration standard curve was plotted to evaluate the retention rate of desert algae polysaccharides after high-pressure homogenization and crushing under different conditions.

[0035] The results of the glucose standard curve are as follows: Figure 1 As shown, the regression curve has the equation y = 1.25049x + 0.05092, and R² = 0.9992, which is close to 1, indicating a good fit.

[0036] This experiment produced reducing sugars from desert algae by acid hydrolysis with 12 mol / L hydrochloric acid: Equal volumes (V mL) of desert algae liquid before and after crushing were taken, and 12 mol / L HCl (liquid-to-solid ratio 1:1) were added. Hydrolysis was carried out in a 100℃ water bath for 2 h. After the reaction, the pH was adjusted to 7.0 with 6 mol / L NaOH. After centrifugation (12000 rpm, 10 min), 1 mL of the supernatant was collected, and 1 mL of DNS reagent was added. The mixture was then boiled in a water bath for 10 min, and the absorbance (A) of the reducing sugar was measured at 540 nm. The polysaccharide content was determined by substituting the measured absorbance (A) of the reducing sugar into a standard curve.

[0037] The formula for calculating the polysaccharide retention rate is as follows: Polysaccharide (mg) = (A - 0.05092) / 1.25049 V 0.9; Polysaccharide retention rate (%) = Polysaccharide content of the broken group / Polysaccharide content of the live algae group 100%.

[0038] Example 1 This embodiment first determines the simulation range of each variable based on the results of single-factor analysis. Then, it optimizes the simulation using a central composite design (CCD) response surface experiment based on the actual conditions and analysis results to predict the relationship between different fragmentation conditions and the effects of desert algae fragmentation rate, chlorophyll and polysaccharide retention rate. The embodiment also provides the corresponding fitting model and regression equation, and finally finds the optimal conditions according to actual needs.

[0039] First, a single-factor experiment was conducted: After cyclic cooling at 4℃, 100 mL of desert algae (Chlorophyta, Chlorella, Chlorella sorokiniana) aqueous suspension was added to the hopper of a high-pressure homogenizer, and the homogenization valve was rotated to pressurize and crush the algae.

[0040] 1. When the crushing time was 6 min and the mass fraction of algal solution was 6%, the crushing pressure was changed (1000, 1100, 1200, 1300, 1400, 1500 bar) to study the effect of high pressure homogenizer crushing on the crushing rate, chlorophyll retention rate and polysaccharide retention rate under the condition. 2. At a crushing pressure of 1400 bar and an algal solution mass fraction of 6%, the crushing time was varied (3, 6, 9, 12, 15, 18 min) to study the effects of high-pressure homogenizer crushing on the crushing rate, chlorophyll retention rate and polysaccharide retention rate under these conditions. 3. At a crushing pressure of 1400 bar and a crushing time of 6 min, the mass fraction of the algal solution was changed (2%, 4%, 6%, 8%, 10%) to study the effect of high-pressure homogenizer crushing on the crushing rate, chlorophyll retention rate and polysaccharide retention rate under these conditions.

[0041] Based on the results of the univariate analysis, appropriate ranges for each parameter were selected for response surface analysis. The univariate results of crushing pressure on crushing rate are as follows: Figure 2 As shown in Figure a, the breakage rate gradually increases with the increase of the breaking pressure, but when the pressure is 1000 bar, the cell wall of the desert algae disintegrates due to insufficient breaking pressure, so the breakage rate approaches 0. Figure 2 b, 2c, 3b, and 3c show that the retention rates of chlorophyll and polysaccharides generally tend to decrease with increasing crushing pressure and crushing time, with a significant decrease in chlorophyll and polysaccharide retention rates when the crushing pressure is greater than 1400 bar. Figure 3 The data shows that the breakage rate gradually increases with the increase of crushing time. Figure 4 The data shows that increasing the mass fraction of the algae solution gradually decreases the breakage rate. Figure 8 This explains the phenomenon: the high-pressure homogenizer breaks down desert algae cells through pressurized shear force. However, an excessively high algae concentration leads to excessively high concentrations and agglomeration, resulting in lower shear force on the inner cells compared to the outer cells, thus preventing cell lysis and leaving some intact cells. Furthermore, in actual homogenization, homogenizer blockage occurs when the algae concentration exceeds 10%. Figure 4 b and 4c show that increasing the mass fraction of the algal solution initially decreased chlorophyll retention and then increased it, while polysaccharide retention initially increased and then decreased.

[0042] Based on the above reasons, in order to broaden the scope of influence and make it more suitable for practical applications, the value ranges of each variable were selected as follows: crushing pressure 1100-1500 bar, crushing time 3-15 min, and mass fraction of added algae solution 2-10%. The specific design is shown in Table 1.

[0043] Table 1 Response Surface Design

[0044] Analyze the fitting results. Analysis of variance was performed on the experimental values ​​of breakage rate (Y1), chlorophyll retention rate (Y2), and polysaccharide retention rate (Y3) in Table 2 using a central composite design (CCD) response surface methodology. The response surface experimental design and results are shown in Table 2. Table 2 Response Surface Experimental Design and Results

[0045] The regression equations for the response surface model, expressed in terms of coded values, are as follows: Y1= 65.98 + 25.86A + 5.75B - 5.04C - 1.9A×B - 2.39A×C - 0.355B×C -5.39A 2 + 1.16B 2 - 0.7209C 2 (R) 2 =0.9986) Y2= 82.77 - 6.33A - 3.38B + 1.01C - 1.03A×B - 0.9062A×C + 1.80B×C- 0.4786A 2 + 0.8064B 2 + 3.62C 2 (R) 2 =0.9845) Y3= 71.89 - 4.36A - 3.74B + 3.48C + 0.1425A×B - 1.13A×C - 0.4525B×C + 10.43A 2 - 1.15B 2 - 2.61C 2 - 3.66A 2 C(R) 2 =0.9751) The above regression equations show that the R-squared values ​​of each regression equation are... 2 A value greater than 0.97 and approaching 1 indicates that the model fits well.

[0046] The statistical results of the response surface methodology experiment on the breakup rate of breakup pressure, breakup time, and mass fraction of added algae solution are shown in Table 3. The p-value of the model is <0.0001, which is extremely significant, while the p-value of the lack-of-fit term is 0.1396, which is not significant. Therefore, the experimental error is very small, indicating that the regression model can predict the experimental results well.

[0047] Table 3 Statistical results of the response surface methodology experiment (breakdown rate)

[0048] Note: This indicates a statistically significant difference (P<0.05). This indicates a highly statistically significant difference (P<0.01). As shown in Table 3, the F-values ​​were ranked as follows: A (6564.23) > B (324.30) > C (248.94), all of which were highly significant (p < 0.0001). The priority of influence was: crushing pressure (A) > crushing time (B) > mass fraction of algal solution added (C). This indicates that crushing pressure is the most critical factor affecting the crushing rate, followed by crushing time, while the influence of algal solution mass fraction is relatively weak.

[0049] The response surface methodology results for the effects of crushing pressure, crushing time, and algal liquor mass fraction on the crushing rate are as follows: Figure 5 As shown, the results indicate that with increasing crushing pressure and crushing time, the desert algae are crushed more thoroughly, thus increasing the crushing rate. Gradually increasing the mass fraction of the algal solution leads to a more viscous solution, and excessively high concentrations may result in insufficient crushing, thus reducing the crushing rate.

[0050] The statistical results of the response surface methodology experiment on chlorophyll retention rate of crushing pressure, crushing time, and mass fraction of added algae solution are shown in Table 4. The p-value of the model is <0.0001, which is extremely significant, while the p-value of the lack-of-fit term is 0.0811, which is not significant. Therefore, the experimental error is very small, indicating that the regression model can predict the experimental results well.

[0051] Table 4 Statistical results of the response surface methodology experiment (chlorophyll retention rate)

[0052] Note: This indicates a statistically significant difference (P<0.05). This indicates a highly statistically significant difference (P<0.01). As shown in Table 4, the F values ​​were ranked as follows: A (396.22) > B (112.56) > C (10.12), all of which were highly significant (p < 0.01). The priority of influence was: crushing pressure (A) > crushing time (B) > mass fraction of algal solution added (C). This indicates that crushing pressure has the most significant negative impact on chlorophyll retention rate, followed by crushing time, while the mass fraction of algal solution has the least impact.

[0053] The response surface methodology results for the effects of disruption pressure, disruption time, and algal solution mass fraction on chlorophyll retention are as follows: Figure 6 As shown, the results indicate that although the breakage rate gradually increases with increasing breakage pressure and breakage time, the chlorophyll retention rate decreases due to the decomposition of chlorophyll caused by local overheating. Gradually increasing the mass fraction of algal solution, although the breakage rate gradually decreases, the chlorophyll retention rate slightly increases because the unbroken algal cells can continue to maintain chlorophyll activity.

[0054] The statistical results of the response surface methodology experiment on polysaccharide retention rate of crushing pressure, crushing time, and mass fraction of added algal solution are shown in Table 5. The p-value of the model is <0.0001, which is extremely significant, while the p-value of the lack-of-fit term is 0.0822, which is not significant. Therefore, the experimental error is very small, indicating that the regression model can predict the experimental results well.

[0055] Table 5 Statistical results of response surface methodology (polysaccharide retention rate)

[0056] Note: This indicates a statistically significant difference (P<0.05). This indicates a highly statistically significant difference (P<0.01). As shown in Table 5, the F values ​​were ranked as follows: A (91.42) > B (67.15) > C (11.59), all of which were highly significant (p < 0.01). The order of influence was: crushing pressure (A) > crushing time (B) > mass fraction of added algal solution (C). This indicates that crushing pressure is the primary factor affecting polysaccharide retention rate.

[0057] The response surface methodology results for the effects of disruption pressure, disruption time, and algal liquor mass fraction on polysaccharide retention are as follows: Figure 7As shown, the results indicate that although the crushing rate gradually increases with increasing crushing pressure and time, local overheating leads to polysaccharide decomposition. The polysaccharide retention rate slightly increases at 1500 bar, possibly due to the significantly increased flow rate caused by high pressure, which shortens the residence time of the material in the high-temperature zone, thus reducing polysaccharide pyrolysis. Furthermore, the increased algal liquor mass fraction has a highly significant impact on polysaccharide retention. This may be because small-molecule chlorophyll is easily released, and the total amount effect dominates, leading to an increased retention rate. Conversely, large-molecule polysaccharides suffer from limited mass transfer, resulting in a greater decrease in extraction efficiency than the increase in total amount, thus leading to a decreased retention rate.

[0058] Example 2 Validate the optimal conditions for the model predictions. Comparative experiment: 100 mL of desert algae suspension was ultrasonically broken up under the conditions of 300 W, total duration of 6 h (5 s of ultrasound, 5 s of intermittent), and ice bath. The mass fraction of algae added was 3%. The results showed that the breakage rate of desert algae was only 20.03%, and the chlorophyll and polysaccharide retention rates were 54.03% and 40.86%, respectively.

[0059] If the actual requirement is a breakage rate ≥90% and a chlorophyll / polysaccharide retention rate ≥70%, the optimal breakage conditions and results recommended by the response surface methodology of the central composite design are as follows: under the conditions of a breakage pressure of 1486 bar, a breakage time of 11 min, and an added algal solution mass fraction of 3%, the breakage rate is 91.59%, the chlorophyll retention rate is 76.93%, and the polysaccharide retention rate is 74.81%.

[0060] To facilitate experimental verification, a specific experiment was conducted under the conditions of a crushing pressure of 1490 bar, a crushing time of 11 min, and an added algal solution mass fraction of 3%. The experimental procedure was as follows: after circulating cooling at 4℃, 100 mL of desert algae suspension (Chlorophyta phylum, Chlorella genus, Chlorella sorokiniana) was added to the hopper of a high-pressure homogenizer, and the homogenization valve was rotated to apply pressure for crushing.

[0061] The results showed a breakage rate of 91.94% (error = 0.38%), a chlorophyll retention rate of 78.25% (error = 1.72%), and a polysaccharide retention rate of 72.41% (error = 3.21%). This indicates that the actual results are close to the model's predicted values, and the errors are all less than 5%, indicating that the model fits reliably and can be used. Chlorophyll and polysaccharides are temperature-sensitive; under ultrasonic conditions, localized overheating can easily lead to decomposition of all three. Compared with the ultrasonic method, the high-pressure homogenization method improved the breakage rate by 71.91%, the chlorophyll retention rate by 24.22%, and the polysaccharide retention rate by 31.55%. The high-pressure homogenization method described in this invention is suitable for the breakage of desert algae and the retention of their active substances.

[0062] Example 3 A range-based single-factor experiment was conducted to validate the model at its predicted optimal value. To verify the optimal value predicted by the model, five gradient experiments were conducted under the conditions of a crushing pressure of 1490 bar and an added algal solution mass fraction of 3%, varying the crushing time (3-15 min) to verify the model fitting results. The experimental procedure was the same as in Implementation 2, and the results are as follows: Gradient 1: When the breaking time is 3 min, the model predicts the following results: breakage rate = 87.66%, chlorophyll retention rate = 84.68%, and polysaccharide retention rate = 79.17%. The actual results are: breakage rate = 84.15% (error: 4.00%); chlorophyll retention rate = 80.97% (error: 4.38%); polysaccharide retention rate = 75.45% (error: 4.70%). Gradient 2: When the breaking time is 6 min, the model predicts the following results: breakage rate = 88.89%, chlorophyll retention rate = 81.24%, and polysaccharide retention rate = 78.07%. The actual results are: breakage rate = 90.85% (error: 2.20%); chlorophyll retention rate = 78.64% (error: 3.20%); and polysaccharide retention rate = 76.35% (error: 2.20%). Gradient 3: When the breaking time is 9 min, the model predicts the following results: breaking rate = 90.70%, chlorophyll retention rate = 78.19%, and polysaccharide retention rate = 76.39%. The actual results are: breaking rate = 92.85% (error: 2.37%); chlorophyll retention rate = 75.99% (error: 2.81%); polysaccharide retention rate = 75.15% (error: 1.62%). Gradient 4: When the breaking time is 12 min, the model predicts the following results: breaking rate = 93.09%, chlorophyll retention rate = 75.55%, and polysaccharide retention rate = 74.13%. The actual results are: breaking rate = 93.85% (error: 0.82%); chlorophyll retention rate = 73.09% (error: 3.26%); and polysaccharide retention rate = 70.71% (error: 4.61%). Gradient 5: When the breaking time is 15 min, the model predicts the following results: breaking rate = 96.06%, chlorophyll retention rate = 73.31%, and polysaccharide retention rate = 71.30%. The actual results are: breaking rate = 97.85% (error: 2.90%), chlorophyll retention rate = 72.18% (error: 1.54%), and polysaccharide retention rate = 70.15% (error: 1.61%).

[0063] The above results show that the actual results are close to the model's predicted values ​​and the errors are all less than 5%, indicating that the model fits reliably and can be used.

[0064] In summary, this invention specifically optimizes the parameters for high-pressure homogenization and disruption of desert algae due to their thick and tough cell walls. It solves the problems of low disruption efficiency, long processing time, and low chlorophyll and polysaccharide retention rates in traditional processes (such as ultrasonic disruption). The optimized parameter range conforms to the conventional operating range of industrial-grade high-pressure homogenizers. The constructed model can predict actual results. After verification, under optimal conditions, it can achieve a disruption rate of ≥90% and a chlorophyll and polysaccharide retention rate of ≥70%, with short processing time (only 9-15 min, shorter than the 15-25 h time required by repeated freeze-thaw disruption (authorization announcement number CN104289281B)) and excellent results. It reconciles the contradiction between disruption rate and active ingredient retention rate, making it suitable for large-scale production.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optimized method for a highly efficient fragmentation process that retains a high concentration of active ingredients from desert algae, characterized in that, Includes the following steps: (1) Screening of characteristic parameters and single-factor experiments: The core characteristic parameters of the high-pressure homogenization method for breaking desert algae were screened: breaking pressure, breaking time and algal liquid mass fraction. Single-factor variable experiments were conducted to investigate the independent influence of each characteristic parameter on the breaking rate, chlorophyll retention rate and polysaccharide retention rate. (2) Response surface experimental design and data acquisition: Based on the effective range of parameters determined by the single-factor variable experiment in step (1), the response surface method was adopted, with crushing pressure, crushing time and algal liquid mass fraction as input variables, and crushing rate, chlorophyll retention rate and polysaccharide retention rate as response variables to design an experimental scheme and obtain statistically significant response surface design experimental data. (3) Construction of regression equation model: Based on the response surface design experimental data obtained in step (2), establish regression equation model, which includes the breakage rate regression equation Y1, the chlorophyll retention rate regression equation Y2, and the polysaccharide retention rate regression equation Y3. (4) Model verification and optimal process determination: The accuracy of the regression equation model obtained in step (3) is verified by experiments. The optimal crushing conditions predicted by the model are selected to meet the preset targets of crushing rate ≥90%, chlorophyll retention rate ≥70%, and polysaccharide retention rate ≥70%.

2. The optimization method according to claim 1, characterized in that, The desert algae mentioned in step (1) are from the genera Nostoc, Chlamydomonas, or Chlorella; the crushing pressure is 1000~1500 bar, the crushing time is 3~18 min, the algal liquid mass fraction is 2~10%, and the crushing temperature is 1~10℃.

3. The optimization method according to claim 1, characterized in that, The key steps of the response surface experimental design in step (2) are as follows: based on the experimental results of the single-factor variables of each characteristic parameter, select the optimal range of values ​​for each characteristic parameter, then use each characteristic parameter as the input variable, and conduct experiments with the breakage rate, chlorophyll retention rate and polysaccharide retention rate as response variables, and finally perform model fitting.

4. The optimization method according to claim 1, characterized in that, The regression equation model described in step (3) has R² ≥ 0.97, p ≤ 0.0001, and a lack-of-fit term p ≥ 0.

05.

5. The optimization method according to claim 1, characterized in that, The regression equation model described in step (3) simultaneously correlates the variable parameters with the breakage rate, chlorophyll retention rate, and polysaccharide retention rate, specifically as follows: Regression equation for breakage rate: Y1 = 65.98 + 25.86A + 5.75B - 5.04C - 1.9A×B - 2.39A×C - 0.355B×C - 5.39A 2 + 1.16B 2 - 0.7209C 2 ; The regression equation for chlorophyll retention rate is: Y2= 82.77 - 6.33A - 3.38B + 1.01C - 1.03A×B - 0.9062A×C + 1.80B×C -0.4786A 2 + 0.8064B 2 + 3.62C 2 ; Regression equation for polysaccharide retention rate: Y3 = 71.89 - 4.36A - 3.74B + 3.48C + 0.1425A×B - 1.13A×C - 0.4525B×C + 10.43A 2 - 1.15B 2 - 2.61C 2 - 3.66A 2 C; Where A is the crushing pressure (bar), B is the crushing time (min), and C is the mass fraction of the added algal solution (%). The p-value of the model is <0.0001, and the p-value of the lack-of-fit term is >0.

05.

6. The optimization method according to claim 1, characterized in that, The optimal crushing conditions described in step (4) can balance high crushing rate, chlorophyll retention rate and polysaccharide retention rate. The crushing pressure is 1486~1490 bar, the crushing time is 11 min, the algal liquid mass fraction is 3%, the crushing rate is ≥91.5%, the chlorophyll retention rate is ≥76.9%, and the polysaccharide retention rate is ≥72.4%.

7. A highly efficient crushing process for preserving active ingredients from desert algae, characterized in that, Includes the following steps: At 1~10℃, a desert algae suspension with a mass fraction of 2~4% was added to the hopper of a high-pressure homogenizer. The crushing pressure was set to 1480~1490 bar and the crushing time was 10~12 min for pressure crushing to obtain a crushed product with high retention of desert algae active substances.

8. The high-efficiency crushing process according to claim 7, characterized in that, The desert algae are from the genera *Nostoc*, *Chlamydomonas*, or *Chlorella*; the solvent for the desert algae suspension is water.

9. The high-efficiency crushing process according to claim 7, characterized in that, The crushing pressure was 1485~1490 bar, the crushing time was 11 min, and the mass fraction of the desert algae suspension was 3%.

10. The high-efficiency crushing process according to claim 7, characterized in that, Breakage rate ≥90%, chlorophyll retention rate ≥70%, polysaccharide retention rate ≥70%.

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