Method for predicting beer malt foam protein and application thereof

Abstract

The invention relates to a method for predicting beer malt foam protein and application thereof, and the method can predict whether the beer malt foam protein prepared from beer barley meets the requirements of a malt user or not by detecting the content of the beer malt foam protein. According to the method, a malt factory selects and determines a proper barley batch before purchasing barley, so that the prepared beer malt foam protein meets beer production requirements, a malt product of which the foam protein does not conform to beer brewing is prevented from being produced, and the prepared beer has good foam retention.

Description

Technical Field

[0001] This invention relates to the field of beer production technology, and to a method for predicting beer malt foam protein and its application. Background Technology

[0002] Beer foam is one of the key characteristics of beer products. As one of the main raw materials for beer brewing, the foaming proteins in malt are an important indicator for measuring the foam characteristics of beer. Current technology typically uses the Coomassie Brilliant Blue assay to detect proteins in malt, thereby evaluating the foam quality of beer brewed using that batch of malt. However, malt is a raw material for beer brewing made from barley through soaking, germination, drying, and roasting. Therefore, the detection of foaming proteins in malt usually requires starting from the preparation of malt from barley. Testing can only be performed after the malt is prepared, which has drawbacks such as long cycle time, retrospective nature, difficulty in product processing, and even impact on malt prices. Moreover, for malt products with foaming proteins unsuitable for beer brewing, it wastes energy and time, and using them in beer brewing may affect the quality of the beer foam. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a method for predicting the foam protein content of beer malt. This method can detect the foam protein content of brewing barley and thus predict whether the foam protein content of the brewing malt made from that barley meets product requirements. Malt mills can use this invention to select suitable barley batches before purchasing, ensuring that the foam protein content of the brewing malt meets the needs of beer production, avoiding the production of malt products with foam protein levels unsuitable for beer brewing, and guaranteeing that the resulting beer has good foam retention.

[0004] This invention provides a method for predicting beer malt foam proteins, comprising the following steps: Grinding: Grind the barley to be tested into barley flour to obtain the barley flour to be tested; Enzymatic hydrolysis: Mix the barley flour to be tested with water, heat, add the mixed enzyme, heat again, add water to obtain saccharified mash, keep warm, cool to room temperature, add water, stir, filter, collect the filtrate to obtain the sample to be tested; the mixed enzyme includes α-amylase, β-glucanase and complex enzyme, and the addition amounts of α-amylase, β-glucanase and complex enzyme are 13-17 μL / 50g barley flour, 18-22 μL / 50g barley flour, and 13-17 mg / 50g barley flour, respectively; Foam protein detection: Take bovine serum protein standard solution, add Coomassie brilliant blue solution to prepare standard sample, use blank sample as reference solution to prepare standard curve; Sample testing: Take the sample to be tested, place it in a colorimetric tube, dilute it with water, add Coomassie Brilliant Blue solution, mix well, and react at room temperature. Use a blank sample as a reference solution to measure the absorbance value. Calculate the foam protein content of the sample to be tested according to the standard curve. Predicting the foam protein content of beer malt: Based on the foam protein content of the sample to be tested, the foam protein content of beer barley is calculated, and the foam protein content of beer malt is predicted.

[0005] In one embodiment, the complex enzyme includes at least two of neutral protease, β-glucanase, xylanase, cellulase, and α-amylase.

[0006] In one embodiment, the enzymatic hydrolysis step includes: mixing the barley flour to be tested with water, carrying out a saccharification reaction, heating in a water bath to 43-47°C, adding mixed enzymes, heating the water bath at a heating rate of 0.8-1.2°C / min, raising the temperature to 68-72°C within 23-27 min, adding water at the same temperature to obtain saccharified mash, keeping it at 68-72°C for 0.8-1.2 h, cooling to room temperature within 10-15 min, adding water, stirring, filtering, and collecting the filtrate.

[0007] In one embodiment, the formula for the standard curve is shown in Equation 1: Equation 1: y = ax + b; Where y is the absorbance of the standard sample and x is the concentration of the standard sample.

[0008] In one embodiment, the foam protein content of the sample to be tested is calculated according to Equation 2: Equation 2: X1 = (A 595 -b) / a*Dilution factor; Where X1 represents the foam protein content of the sample to be tested, in mg / L, and A 595 The absorbance of the sample to be tested is given by equation 1. The dilution factor is the dilution factor in the sample detection process.

[0009] In one embodiment, the calculation of the foam protein content of brewing barley includes: calculating the foam protein content of brewing barley according to Formula 3; Equation 3: X2 = X1 * 8 / 1000; Where X2 is the foam protein content of malting barley, in g / kg, and X1 is the foam protein content of the sample to be tested, in mg / L.

[0010] In one embodiment, the prediction of the foam protein content of beer malt includes: comparing the foam protein content of beer barley with a predetermined value of the foam protein content of beer malt; if the foam protein content of beer barley is ≥ the predetermined value, then the barley to be tested is deemed qualified and the foam protein content of the beer malt made from the barley to be tested is deemed qualified.

[0011] The predetermined values ​​for the foam protein content of the aforementioned beer malt are determined based on the beer brewing requirements.

[0012] In one embodiment, the sample detection step includes: taking the sample to be tested, placing it in a colorimetric tube, adding water at a volume ratio of (6-8):1 to dilute it, taking the diluted sample to be tested, adding Coomassie Brilliant Blue solution at a volume ratio of (4-6):1 to dilute it, mixing it well, reacting it at room temperature for 8-12 minutes, using a blank sample as a reference solution, measuring the absorbance value at a wavelength of 595 nm using a spectrophotometer, and calculating the foam protein content of the sample to be tested according to the standard curve.

[0013] In one embodiment, the absorbance value was measured using a 1 cm cuvette.

[0014] This invention also provides the application of the method in the quality control of brewing barley.

[0015] The present invention also provides a quality control method for brewing barley, comprising the following steps: using the method to test the barley to be tested, and when the prediction result indicates that the barley to be tested is qualified, it is retained.

[0016] The present invention also provides the application of the quality control method for brewing barley in the quality control of brewing malt.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for predicting foam protein in beer malt and its application. This method can predict whether the foam protein content of beer malt made from that barley meets product requirements by detecting the foam protein content. Malt plants can use this invention to select suitable barley batches before purchasing, ensuring that the foam protein in the resulting beer malt meets the needs of beer production, avoiding the production of malt products with foam protein that does not meet beer brewing requirements, and guaranteeing that the brewed beer has good foam retention. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description will be given below with reference to relevant embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0020] source: The α-amylase used in this embodiment is a commercially available liquid enzyme preparation, with the product instructions indicating α-amylase ≥280,000 U / mL; the β-glucanase is a commercially available liquid enzyme preparation, with the product instructions indicating β-glucanase ≥320 EGU / g; the complex enzyme is a commercially available solid enzyme preparation, with the product instructions indicating it contains neutral protease ≥8,000 U / g, β-glucanase ≥1,500 U / g, xylanase ≥5,000 U / g, cellulase ≥10,000 U / g, and α-amylase ≥3,000 U / g.

[0021] Unless otherwise specified, all reagents, materials, and equipment used in this embodiment are commercially available; unless otherwise specified, all test methods are conventional test methods in this field.

[0022] Example 1 A method for predicting beer malt foam protein.

[0023] After barley grains are crushed, they are hydrolyzed with enzymes to produce wort. The content of barley foam protein is then tested and calculated, as follows: (1) Crushing: Crush the barley grains to a mesh size of 60-80; (2) Enzymatic hydrolysis: Weigh 50g of crushed barley grains (accurate to 0.1g) into a saccharification cup, add 200mL of deionized water, mix well, and place in a saccharification apparatus. Heat in a water bath to 45℃, then add α-amylase, β-glucanase, and a complex enzyme at 15μL / 50g, 20μL / 50g, and 15mg / 50g, respectively. Then heat the water bath at a rate of 1℃ / min, reaching 70℃ within 25min. Add 100mL of 70℃ water to the saccharification cup, keep the mash at 70℃ for 1h, and then rapidly cool to room temperature within 10min-15min. Rinse the stirrer with water, wipe the outer wall of the saccharification cup dry, and add water to ensure the contents are accurately weighed to 450.0g. Stir the saccharification mash with a glass rod and filter it with medium-speed filter paper. Return the initial 100 mL of filtrate to be filtered again and collect the filtrate in a dry beaker to obtain the sample to be tested. (3) Foam protein detection: ① Preparation of Standard Curve: Pipette 0.0 mL, 1 mL, 2 mL, 3 mL, 4 mL, 5 mL, and 6 mL of bovine serum protein standard solution into 10 mL volumetric flasks (protein concentrations of 0 mg, 0.2 mg, 0.3 mg, 0.5 mg, 0.8 mg, and 1.0 mg, respectively). Dilute to volume with distilled water. Pipette 1 mL of each of the above samples (1-6) into a colorimetric tube, add 5 mL of Coomassie Brilliant Blue G-250 solution, and mix well (gently invert twice to avoid excessive foaming). For the blank sample, pipette 1 mL of sample 0 into a colorimetric tube, add 5 mL of Coomassie Brilliant Blue solution, and mix well. React at room temperature for 10 min. Using a 1 cm thick cuvette and the blank sample as a reference, measure the absorbance at 595 nm using a spectrophotometer. Plot a standard curve with absorbance as the ordinate and standard protein concentration (mg / L) as the abscissa. Calculate the values ​​of a and b using the curve y = ax + b.

[0024] ② Sample Detection: Pipette 1 mL of the sample to be tested (the volume can be adjusted appropriately according to the protein content in the sample) into a 10 mL colorimetric tube, add 7 mL of distilled water, then pipette 1 mL of the diluted sample into the colorimetric tube, add 5 mL of Coomassie Brilliant Blue G-250 solution, and shake well (gently invert twice to avoid excessive foaming). Incubate at constant room temperature for 10 min. For the blank sample, pipette 1 mL of distilled water into a colorimetric tube, add 5 mL of Coomassie Brilliant Blue solution, and shake well. Using a 1 cm cuvette with the blank sample as a reference solution, measure the absorbance at a wavelength of 595 nm using a spectrophotometer. 595 The protein content in the sample is calculated based on the standard curve.

[0025] ③ Protein content calculation: X1 = (A 595 -b) / a*Dilution factor X2 = X1 * 8 / 1000 In the formula: X1 — Sample foam protein content, mg / L X2 – The content of foam protein in brewing barley, g / kg A 595 —Sample absorbance a, b — Values ​​of a and b obtained from the curve. (4) Prediction: The foam protein content of the calculated brewing barley is compared with the predetermined value of the foam protein content required for brewing malt. If the foam protein content of the brewing barley is ≥ the predetermined value, the batch of barley is deemed qualified and the foam protein content of the malt made from the barley will meet the requirements for beer brewing.

[0026] Example 2 Following the method in Example 1, the foam protein content of barley varieties Copeland, Maximus, Spartacus, and Synergy was detected. Simultaneously, the foam protein content of beer malt produced from these four barley varieties using conventional malting processes was detected according to the beer malt foam protein detection method (specifically, the Coomassie Brilliant Blue method). The above barley was used to prepare lager beer, and the foam protein content of the beer malt was required to be ≥4 g / kg, i.e., the predetermined value was 4 g / kg. The results are shown in Table 1.

[0027] Table 1. Predicted values ​​of various barley varieties obtained according to the method in Example 1, and foam protein detection values ​​of the prepared beer malt.

[0028] Note: The data in the table above are the average values ​​after three parallel experiments, with the detection error bar added.

[0029] The results showed that the foam protein content of barley detected by the method of this invention was close to that of the beer malt produced from it. The foam protein content of barley detected by this method was greater than the predetermined value. Therefore, it was predicted that the foam protein content of malt produced from the aforementioned different barley varieties should also meet the requirements for beer brewing. Furthermore, the foam protein content of malt actually obtained through conventional malting processes was also greater than the predetermined value, meeting the requirements for beer brewing. The results were consistent. It is evident that the method of this invention, by detecting the foam protein content of beer barley, can effectively predict the foam protein content of beer malt and determine whether barley meets the requirements for beer brewing at the barley procurement stage.

[0030] The beer malt obtained from the above barley was used to brew bottled beer, and the foam retention of the bottled beer was tested. The test results of the foam retention are shown in Table 2, which meet the requirements of GB4927 "Beer" for premium bottled beer.

[0031] Table 2. Foam retention of finished beer products

[0032] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0033] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for predicting beer malt foam proteins, characterized in that, Includes the following steps: Grinding: Grind the barley to be tested into barley flour to obtain the barley flour to be tested; Enzymatic hydrolysis: Mix the barley flour to be tested with water, heat, add the mixed enzyme, heat again, add water to obtain saccharified mash, keep warm, cool to room temperature, add water, stir, filter, collect the filtrate to obtain the sample to be tested; the mixed enzyme includes α-amylase, β-glucanase and complex enzyme, and the addition amounts of α-amylase, β-glucanase and complex enzyme are 13-17 μL / 50g barley flour, 18-22 μL / 50g barley flour, and 13-17 mg / 50g barley flour, respectively; Foam protein detection: Take bovine serum protein standard solution, add Coomassie brilliant blue solution to prepare standard sample, use blank sample as reference solution to prepare standard curve; Sample testing: Take the sample to be tested, place it in a colorimetric tube, dilute it with water, add Coomassie Brilliant Blue solution, mix well, and react at room temperature. Use a blank sample as a reference solution to measure the absorbance value. Calculate the foam protein content of the sample to be tested according to the standard curve. Predicting the foam protein content of beer malt: Based on the foam protein content of the sample to be tested, the foam protein content of beer barley is calculated, and the foam protein content of beer malt is predicted.

2. The method according to claim 1, characterized in that, The enzymatic hydrolysis step includes: mixing the barley flour to be tested with water, carrying out a saccharification reaction, heating in a water bath to 43-47℃, adding mixed enzymes, heating the water bath at a heating rate of 0.8-1.2℃ / min, raising the temperature to 68-72℃ within 23-27 min, adding water at the same temperature to obtain saccharified mash, keeping it at 68-72℃ for 0.8-1.2 h, cooling it to room temperature within 10-15 min, adding water, stirring, filtering, and collecting the filtrate.

3. The method according to claim 1, characterized in that, The formula for the standard curve is shown in Equation 1: Equation 1: y = ax + b; Where y is the absorbance of the standard sample and x is the concentration of the standard sample.

4. The method according to claim 3, characterized in that, The foam protein content of the sample to be tested was calculated according to Formula 2: Equation 2: X1 = (A 595 -b) / a*Dilution factor; Where X1 represents the foam protein content of the sample to be tested, in mg / L, and A 595 The absorbance of the sample to be tested is given by equation 1. The dilution factor is the dilution factor in the sample detection process.

5. The method according to claim 4, characterized in that, The calculation of the foam protein content of malting barley includes: calculating the foam protein content of malting barley according to Formula 3; Equation 3: X2 = X1 * 8 / 1000; Where X2 is the foam protein content of malting barley, in g / kg, and X1 is the foam protein content of the sample to be tested, in mg / L.

6. The method according to claim 5, characterized in that, The prediction of foam protein content in beer malt includes: comparing the foam protein content of beer barley with a predetermined value of foam protein content in beer malt; if the foam protein content of beer barley is ≥ the predetermined value, then the barley to be tested is deemed qualified, and the foam protein content of beer malt made from the barley to be tested is deemed qualified.

7. The method according to any one of claims 1-6, characterized in that, The sample detection steps include: taking the sample to be tested, placing it in a colorimetric tube, adding water at a volume ratio of (6-8):1 to dilute it, taking the diluted sample to be tested, adding Coomassie Brilliant Blue solution at a volume ratio of (4-6):1 to the diluted sample to be tested, mixing well, reacting at room temperature for 8-12 minutes, using a blank sample as a reference solution, measuring the absorbance value at a wavelength of 595 nm using a spectrophotometer, and calculating the foam protein content of the sample to be tested according to the standard curve.

8. The application of the method according to any one of claims 1-7 in the quality control of brewing barley.

9. A method for quality control of brewing barley, characterized in that, The method includes the following steps: testing the barley to be tested using the method described in any one of claims 1-7, and retaining the barley when the prediction result indicates that it is qualified.

10. The application of the quality control method for brewing barley according to claim 9 in the quality control of brewing malt.

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