Starch flocculation characteristic detection method based on enzymatic liquefaction and visual identification

Abstract

The invention discloses a starch flocculation characteristic detection method based on enzymatic liquefaction and visual identification, and relates to the technical field of starch quality detection and performance evaluation.The starch flocculation characteristic detection method comprises the steps that firstly, a sample is prepared, a to-be-detected starch sample and tap water are mixed according to a preset mass-volume ratio, and oscillation and shaking up are conducted to form a starch milk suspension; adjusting the system, namely adjusting the pH value of the starch emulsion suspension to 5.2-6.5 by using a dilute acid or dilute alkali solution; carrying out enzymolysis and liquefaction, adding a proper amount of amylase solution into the starch milk suspension with the adjusted pH value, and continuously oscillating or stirring under a heating condition until the system is completely liquefied; cooling, standing and observing, naturally cooling the completely liquefied liquid to room temperature, standing, observing whether floccules are generated on the liquid level or the solution in the standing process or after standing, and evaluating the aggregation state of the floccules; and finally judging a result. Compared with the prior art, the method has the advantages of rapidness, intuition, low cost, strong simulation, good discrimination and flexibility.

Description

Technical Field

[0001] This invention relates to the field of starch quality testing and performance evaluation technology, specifically to a method for detecting starch flocculation characteristics based on enzymatic liquefaction and visual recognition. Background Technology

[0002] The flocculation properties of starch are a key indicator affecting its performance in applications such as food, papermaking, textiles, and brewing. Starches with good flocculation properties (typically with a high amylose content) are more likely to form stable gels or flocs in specific processes, which is crucial to the texture, water retention, or sedimentation effect of the final product. Currently, methods for assessing starch flocculation properties mostly employ instrumental analysis, such as turbidimeters, rheometers, or sedimentation centrifugation. While these methods are accurate, they suffer from drawbacks such as expensive equipment, complex operation, long processing times, and unsuitability for rapid screening on production lines.

[0003] Therefore, there is an urgent need for a detection method that is low-cost, easy to operate, provides intuitive results, and can quickly determine the quality of starch flocculation. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rapid detection method for starch flocculation characteristics based on enzymatic liquefaction and visual recognition. This method does not require complex instruments and can effectively distinguish and evaluate the flocculation characteristics of starch by simulating specific process conditions and observing the morphology of flocs.

[0005] Specifically, the technical solution provided by this invention is: a method for detecting starch flocculation characteristics based on enzymatic liquefaction and visual recognition, comprising: Step 1, Sample preparation: Mix the starch sample to be tested with tap water at a predetermined mass-volume ratio, shake well to form a starch emulsion suspension; Step 2, System Adjustment: Adjust the pH of the starch milk suspension to 5.2-6.5 using a dilute acid or dilute alkali solution; Step 3, Enzymatic hydrolysis and liquefaction: Add an appropriate amount of amylase solution to the starch milk suspension with the pH value adjusted, and continue to shake or stir under heating conditions until the system is completely liquefied; Step 4, Cooling and Observation: Allow the completely liquefied liquid to cool naturally to room temperature and let it stand. Observe whether flocculent matter is generated on the surface of the liquid or in the solution during and after the standing process, and assess the aggregation state of the flocculent matter. Step 5, Result Judgment: (1) If the amount of flocculent material produced is large, the particles are obvious, and they can quickly clump together to form a compact clump that is easy to settle, then the flocculation characteristics of the starch sample to be tested are good. (2) If the generated flocs are sparse, small, loosely clustered or suspended and dispersed and do not settle easily, the starch sample to be tested is judged to have poor flocculation characteristics. (3) If almost no visible flocculent matter is produced, the starch sample is considered to have no flocculation properties.

[0006] Preferably, in step 1, the ratio of the starch sample to tap water is 1:2 to 1:4 g / mL.

[0007] Preferably, the ratio of the starch sample to tap water is 1:3 g / mL.

[0008] Preferably, in step 2, the pH value of the starch milk suspension is 5.6-5.8.

[0009] Preferably, in step 3, the criteria for complete liquefaction are: the system changes from turbid to clear or translucent, and the viscosity decreases significantly; heating is performed using an electric furnace or water bath, and the system is kept in a state of slight boiling several times during the heating process to promote the reaction.

[0010] Preferably, in step 3, the amylase is a thermostable α-amylase, and the amount added is 2-6 drops of 2000-4000 U / mL enzyme solution per 25g of starch.

[0011] Compared with the prior art, the advantages of this invention are: (1) fast and intuitive: the entire detection process can be completed in 20-50 minutes, and the results can be judged by visual observation without waiting for long sedimentation or relying on instrument readings.

[0012] (2) Low cost: Only conventional laboratory glassware, heating source and pH test paper (or pH meter) are needed. The reagent consumption is very small, making it particularly suitable for quality control in small and medium-sized enterprises or production sites.

[0013] (3) Strong simulation: The gelatinization and liquefaction process of starch in many industrial applications was simulated by enzymatic hydrolysis and heating. The subsequent aggregation behavior of the components that were not completely decomposed in this process was observed. The results showed good correlation with the flocculation performance of starch in actual applications.

[0014] (4) Good differentiation: By using the core visual criteria of "whether it clumps together" and "the tightness of the clumps", it can effectively distinguish the significant differences in flocculation characteristics between high amylose, ordinary starch and modified starch (such as hydroxypropylated and acetate esterified starch).

[0015] (5) Flexible methods: It can be used as a qualitative screening method, or semi-quantitative analysis can be carried out by introducing simple image comparison cards or sedimentation volume measurement, and it has strong scalability. Attached Figure Description

[0016] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0017] Figure 1This is a schematic diagram of a compact clump with good flocculation properties after starch flocculation characteristic testing according to the present invention.

[0018] Figure 2 This is a schematic diagram of loose flocculent material with poor flocculation properties after starch flocculation characteristic testing according to the present invention.

[0019] Figure 3 This is a schematic diagram of a turbid liquid with extremely poor or no flocculation after testing for starch flocculation characteristics according to the present invention. Detailed Implementation

[0020] Example 1 This embodiment uses this method to compare the flocculation properties of corn starch from different sources.

[0021] Step 1: Weigh 25.0g each of three different brands of ordinary corn starch samples A, B and C, and place them in 250mL Erlenmeyer flasks.

[0022] Step 2: Add 75mL of tap water from the same batch to each bottle, stopper the bottles, and shake vigorously for 2 minutes to form a uniform suspension.

[0023] Step 3: Use 0.1 mol / L dilute hydrochloric acid or sodium hydroxide solution to precisely adjust the pH of each suspension to 5.7 ± 0.1.

[0024] Step 4: Add 4 drops of α-amylase solution with an activity of approximately 3000 U / mL to each conical flask.

[0025] Step 5: Place the conical flask on a temperature-controlled electric stove and gently shake the flask with your wrist while heating. Keep the liquid at a gentle boil until it becomes clear and fluid. This process takes approximately 5-10 minutes. You can briefly stop heating to observe the liquid during this time. If it is not completely liquefied, reheat it until it reaches a gentle boil again.

[0026] Step 6: Stop heating, place the conical flask on the lab bench to cool naturally to room temperature (about 25°C), and then let it stand for 20 minutes.

[0027] Step 7, Observation and Judgment: (1) such as Figure 1 As shown, after sample A cooled, a large amount of cotton-like precipitate quickly appeared. The precipitate clumped tightly together. When the bottle was gently shaken, the upper layer of liquid became clear, while the lower layer remained a solid mass. This indicates good flocculation properties.

[0028] (2) For example Figure 2 As shown, sample B exhibited a small amount of cloud-like flocculent matter, but the particles were fine and dispersed in the liquid. After standing, only some of them slowly settled, without forming dense clumps. It was determined to have poor flocculation properties.

[0029] (3) such as Figure 3As shown, sample C remained a turbid liquid with only a very small amount of powdery precipitate at the bottom and no flocculent matter. It was determined to have extremely poor flocculation properties.

[0030] Example 2 This embodiment follows the steps of Example 1 to test potato starch (typically high in amylose) and cassava starch (typically low in amylose). The results showed that potato starch, upon liquefaction and cooling, formed very typical and compact white flocculent clumps; while cassava starch produced only a very small amount of loose flocculent matter. This method clearly distinguishes the inherent differences in flocculation characteristics between the two.

[0031] In terms of industrial applications, this method can be widely used for rapid screening of the quality of starch products leaving the factory, and for monitoring the stability of the flocculation performance of different batches of products. It can also be applied to the incoming material inspection of starch users (such as food factories, paper mills, and feed mills) to quickly determine whether the raw starch meets the flocculation requirements of the production process.

[0032] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for detecting starch flocculation characteristics based on enzymatic liquefaction and visual recognition, characterized in that... include: Step 1, Sample preparation: Mix the starch sample to be tested with tap water at a predetermined mass-volume ratio, shake well to form a starch emulsion suspension; Step 2, System Adjustment: Adjust the pH of the starch milk suspension to 5.2-6.5 using a dilute acid or dilute alkali solution; Step 3, Enzymatic hydrolysis and liquefaction: Add an appropriate amount of amylase solution to the starch milk suspension with the pH value adjusted, and continue to shake or stir under heating conditions until the system is completely liquefied; Step 4, Cooling and Observation: Allow the completely liquefied liquid to cool naturally to room temperature and let it stand. Observe whether flocculent matter is generated on the surface of the liquid or in the solution during and after the standing process, and assess the aggregation state of the flocculent matter. Step 5, Result Judgment: (1) If the amount of flocculent material produced is large, the particles are obvious, and they can quickly clump together to form a compact clump that is easy to settle, then the flocculation characteristics of the starch sample to be tested are good. (2) If the generated flocs are sparse, small, loosely clustered or suspended and dispersed and do not settle easily, the starch sample to be tested is judged to have poor flocculation characteristics. (3) If almost no visible flocculent matter is produced, the starch sample is considered to have no flocculation properties.

2. The method for detecting starch flocculation characteristics based on enzymatic liquefaction and visual recognition according to claim 1, characterized in that: In step 1, the ratio of the starch sample to tap water is 1:2 to 1:4 g / mL.

3. The method for detecting starch flocculation characteristics based on enzymatic liquefaction and visual recognition according to claim 2, characterized in that: The ratio of the starch sample to tap water was 1:3 g / mL.

4. The method for detecting starch flocculation characteristics based on enzymatic liquefaction and visual recognition according to claim 1, characterized in that: In step 2, the pH value of the starch milk suspension is 5.6-5.

8.

5. The method for detecting starch flocculation characteristics based on enzymatic liquefaction and visual recognition according to claim 1, characterized in that... In step 3, the criteria for complete liquefaction are: the system changes from turbid to clear or translucent, and the viscosity decreases significantly; heating is carried out using an electric furnace or water bath, and the system is kept in a state of slight boiling several times during the heating process to promote the reaction.

6. The method for detecting starch flocculation characteristics based on enzymatic liquefaction and visual recognition according to claim 1, characterized in that: In step 3, the amylase is a thermostable α-amylase, and the amount added is 2-6 drops of 2000-4000 U / mL enzyme solution per 25g of starch.

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