Malt solubility evaluation method

Abstract

The invention discloses a malt solubility evaluation method, and belongs to the field of malt evaluation. According to the technical scheme, the malt solubility is defined according to the malt dissolution index, and the lower the malt dissolution index is, the better the malt dissolution is. The method is applied to the aspect of malt solubility evaluation, solves the problems of multi-index dependence, low detection efficiency and population mean value distortion in the existing method, realizes rapid and accurate quantitative detection of the malt solubility index, and meets the urgent requirements of mass production on rapid evaluation of the malt solubility and rapid adjustment of a malting process.

Description

Technical Field

[0001] The invention belongs to the field of malt evaluation, and in particular relates to a malt solubility evaluation method. Background Art

[0002] Malt, the core raw material for beer brewing, is a product obtained from barley through the malting process. During the malting process, barley absorbs water and germinates. The embryo secretes gibberellins, which stimulate the aleurone layer to produce various hydrolytic enzymes. These hydrolytic enzymes are transported to the endosperm and continuously break down macromolecules. The soluble low-molecular sugars and nitrogen-containing substances continuously increase, causing the entire endosperm structure to change from tough to loose. This phenomenon is called malt dissolution [Guan Dunyi, Beer Industry Handbook [M], Beijing: China Light Industry Press, 2007]. Solubility is a key indicator of malt quality and directly determines the quality, cost, and flavor stability of beer. Malt that is poorly dissolved contains more vitreous particles, has low enzyme activity, slow saccharification, and low extract, resulting in poor abiotic stability of the beer. Malt that is excessively dissolved grows vigorously, resulting in significant root and bud loss, resulting in a weak beer flavor and poor foam. Malt that is moderately dissolved has excellent brewing properties and is fundamental to stable beer quality.

[0003] Currently, there's no unified evaluation method or standard for determining malt solubility. During the germination stage, experienced malt makers often rub the green malt between their thumb and index finger to assess dissolution. If the endosperm is powdery and loose, it indicates good dissolution; if it forms clumps and cannot be crushed, it indicates poor dissolution. Finished malt is often judged by tasting. If the malt is loose and crumbly, it's considered good dissolution; if the kernels are hard and difficult to bite through, it indicates poor dissolution. These methods are highly subjective and cannot be quantified, making them suitable only for empirical, rough assessments.

[0004] The malt solubility evaluation system covers multiple dimensions of indicators, including indicators such as crispness, coarse-fine powder difference, and saccharification power, which indicate starch dissolution; Kuhlbach value (Kulbach value) and α-amino nitrogen, which indicate protein dissolution; and indicators such as β-glucan and viscosity, which reflect cell dissolution. OzkaRa et al. [R. OzkaRa, A. Basman, H. Koksel, et al. Effects of cultivar and environment on β-glucan content and malting quality of Turkish barleys. Journal of the Institute of Brewing. 1998, 104(4): 217-220] believe that β-glucan is a key indicator connecting variety characteristics and malt quality. Its content changes are significantly correlated with physical indicators such as crispness and viscosity, as well as chemical indicators such as the Kuhlbach index, and can be used as an important reference for evaluating malt solubility. High β-glucan content may correspond to lower crispness (insufficient endosperm dissolution) or higher viscosity (inadequate cell wall degradation). By measuring β-glucan content, key indicators such as brittleness (correlation coefficient: -0.899*), Kupelbach value (correlation coefficient: -0.734*), coarse / fine powder difference (correlation coefficient: 0.675*), and viscosity (correlation coefficient: 0.755*) can be indirectly assessed, providing data support for barley variety screening, growing area optimization, and malting process adjustments. Gastl et al. [M. Gastl, M. Kupetz, and T. Becker, Determination of Cytolytic Malt Modification–Part II Impact on Wort Separation. Journal of The American Society of Brewing Chemists. 2021, Vol. 79, No. 1, 66–74] believe that brittleness, viscosity, and β-glucan content are the primary analytical indicators for evaluating malt cell lysis in malt quality control. Cell lysis describes the enzymatic breakdown of grain cell wall polysaccharides, primarily β-glucan and arabinoxylan. Xu Jufei et al. [Xu Jufei, Kang Jian, Gu Fanghong et al., Key malting parameters affecting malt solubility and parameter optimization, Food and Fermentation Industries, 2015, 41(8):332] believe that the fluorescent staining method can more realistically reflect the dissolution of malt and is relatively simple and intuitive. Wheat kernels are cut into longitudinal sections and stained. Since Calcofluor fluorescent whitening agent can specifically bind to β-glucan, the undissolved cell walls will show blue fluorescence after staining, while the dissolved parts will show light blue. The malt solubility can be obtained by calculating the staining ratio.However, this method requires professional cutting equipment and fluorescence detector software, which is relatively cumbersome to operate and has subjective errors. The degradation degree of the endosperm cell wall can be indirectly evaluated by measuring the malt β-glucan content using the Megazyme kit. However, the β-glucan measured by this method includes partially degraded small molecules and undegraded macromolecules, which cannot accurately reflect the solubility of malt. Edney et al. [MJ Edney, JK Eglinton, HM Collins, et al. Importance of Endosperm Modification for Malt Wort Fermentability, The Institute of Brewing & Distilling, 2007, 113 (2)] believe that the endosperm dissolution process is very complex and is affected by a series of barley characteristics, including genetic genes, growth conditions and malt factory processing conditions. Each barley variety has its own specific dissolution mode and dissolution rate. Barley growth conditions will also affect the potential for endosperm dissolution. High protein caused by drought, excess nitrogen or other environmental factors will seriously change the dissolution properties of barley samples. Hard plasmids also show a slower dissolution rate than powdery plasmids.

[0005] Currently, most breweries comprehensively evaluate malt solubility by testing its crispness, coarse-fine ratio, saccharifying power, Kuhlbach value (Kulbach value), α-amino nitrogen, and β-glucan content. Research has shown that crispness (>80), coarse-fine ratio (<2.0%), saccharifying power (>250 WK), and Kuhlbach value (42%-45%) are key parameters for measuring the balance between starch and protein degradation, while β-glucan content (<110 mg / 100 g) reflects the uniformity of cell wall degradation. However, the solubility characteristics of different barley varieties vary significantly.

[0006] Chinese patent CN 112924337 B provides a method for evaluating malt solubility, which uses the wheat grains below the dry-soaked wheat layer before the end of the dry-soaking step as an indirect evaluation target for malt solubility. At least 50 wheat grain samples are randomly selected from each dry-soaking step, the surface moisture is wiped off and the grains are cut longitudinally. The number of wheat grains is counted based on the dissolution of the half-grain cut surface, and the soaking index (IT) is calculated. When the soaking index is less than 300, it reflects that the malt dissolution is good; when the soaking index is between 300-350, it reflects that the malt solubility is poor; when the soaking index is greater than 350, it reflects that the malt solubility is poor. This method is suitable for real-time determination of malt solubility in the soaking stage of large-scale production processes and timely process adjustments. However, the detection process is cumbersome and the judgment of the cut surface is subjective. It is only applicable to the soaking process and cannot be used to judge the finished malt.

[0007] From the above, it can be seen that the existing malt solubility evaluation technology has the following defects:

[0008] 1. Defect of multi-indicator reliance: The current solubility evaluation requires comprehensive consideration of multiple key indicators, such as brittleness, inventory value, β-glucan, etc. The indicators are complicated and there is a lack of unified judgment standards in the industry.

[0009] 2. Low detection efficiency: Traditional methods include six key indicators such as saccharification power, storage value, and β-glucan. Before testing, malt must be prepared into wort. The operation process is cumbersome, and different testing instruments must be used for each indicator test. The testing cost is high, time-consuming and labor-intensive, and the detection efficiency is low.

[0010] 3. Group mean distortion defect: The test results of conventional malt quality indicators reflect the group mean, which is actually the mixed mean of 50g of malt (about 1200-1400 grains) after crushing, and there is a problem of averaging. The crushed mixture cannot reflect the true solubility of a single grain, nor can it reflect the difference in solubility between different grains. For example, if 600 grains of under-dissolved malt are mixed and crushed with 600 grains of over-dissolved malt, the test results will show that they are well dissolved and meet the quality standards, but the solubility of the single grain malt does not meet the requirements, and the results may be misleading.

[0011] 4. Production lag: Malt factories usually feed materials continuously in large-scale production. Routine malt index testing takes 36 hours to complete. By the time abnormal malt indexes are discovered, continuous feeding has already occurred, which may result in multiple batches of products being unqualified and there is a lag in testing.

[0012] In summary, the existing malt solubility evaluation methods have problems such as multi-index dependence, low detection efficiency, and distortion of group means, which makes it difficult to meet the needs of large-scale production for rapid, accurate, and quantitative detection. Summary of the Invention

[0013] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to overcome the problems of multiple index dependence, low detection efficiency, and group mean distortion in the existing malt solubility evaluation methods. In order to meet the needs of large-scale production for rapid detection and accurate quantitative analysis of malt solubility, a fast, simple and accurate malt solubility index evaluation method is proposed.

[0014] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0015] The present invention provides a method for evaluating malt solubility, wherein malt solubility is defined according to a malt solubility index. The lower the malt solubility index, the better the malt solubility. The malt solubility index is calculated by the following method:

[0016] MI=5.867-0.031×ALI-0.026×FD;

[0017] In the above formula, MI is the malt solubility index, ALI is the leaf bud index, and FD is the single grain grinding degree.

[0018] Solubility is an important indicator for evaluating malt quality. For malt factories, it is an evaluation indicator to check whether the malting process is appropriate; for breweries, it is an important reference for formulating saccharification processes. Figure 1 As shown in Table 1, the above-mentioned malt solubility evaluation method innovatively introduces the dual parameters of leaf bud index (morphological index) and single grain crushing degree (physical index) to replace the traditional multi-biochemical index detection system, significantly simplifying the malt solubility evaluation process while improving detection efficiency and accuracy. The specific beneficial effects are shown in Table 1.

[0019] Table 1 Comprehensive comparison of detection methods

[0020]

[0021]

[0022] This invention significantly improves the efficiency and accuracy of malt solubility testing by streamlining detection indicators, optimizing evaluation formulas, and increasing detection resolution. Compared with traditional methods, this invention not only significantly reduces detection time and costs, but also significantly enhances the representativeness and reliability of test results through single-particle detection and a low coefficient of variation. These innovations and technical advantages provide malt mills and breweries with a more efficient and accurate malt quality evaluation tool that can better meet the needs of real-time process adjustments during production.

[0023] Furthermore, the R-square value of the above formula model was 0.893, indicating that the leaf bud index and single grain crushing degree could explain 89.3% of the variation of the malt solubility index.

[0024] Preferably, when 0.50<MI≤1.00, the malt dissolves well; when 1.00<MI≤1.50, the malt dissolves insufficiently; and when MI>1.50, the malt dissolves poorly.

[0025] Preferably, the leaf bud index is calculated by the following formula:

[0026]

[0027] In the above, N1, N2, N3, N4, and N5 represent the number of malt grains in which the ratio of leaf bud length to grain length is 0 to 1 / 4, 1 / 4 to 1 / 2, 1 / 2 to 3 / 4, 3 / 4 to 1, and >1, respectively.

[0028] Preferably, the leaf bud index is obtained by the following method: boiling a malt sample, cooling the grains, and making the epidermis transparent, observing the length of the leaf buds through the epidermis, analyzing the ratio of the leaf bud length of each grain of malt to the grain length, and classifying them according to 0-1 / 4, 1 / 4-1 / 2, 1 / 2-3 / 4, 3 / 4-1, and >1, and statistically obtaining N1, N2, N3, N4, and N5.

[0029] Preferably, the leaf bud index is obtained by the following method:

[0030] Sample preparation: Select 100 grains of malt sample, place them in a beaker, and add 100 mL of distilled water;

[0031] Boiling treatment: Place the beaker on the hotplate, boil for 5-6 minutes, and then cool at room temperature for 30 minutes;

[0032] Observation and classification: After the grains are cooled, the skin becomes transparent. Observe the length of the leaf buds through the skin and calculate the ratio of the leaf bud length to the grain length of each grain. Classify them according to 0-1 / 4, 1 / 2-3 / 4, 3 / 4-1, and >1, and statistically obtain N1, N2, N3, N4, and N5.

[0033] Calculation of leaf bud index.

[0034] The leaf bud length ratio reflects the overall solubility of malt. Kernels with a leaf bud length ratio of 0 to 1 / 4 are ungerminated or slow-growing, resulting in poor solubility. Kernels with a leaf bud length ratio of 1 / 4 to 1 / 2 indicate insufficient solubility. Kernels with a leaf bud length ratio of 1 / 2 to 3 / 4 have good solubility. Kernels with a leaf bud length ratio of 3 / 4 to 1 have good solubility. Kernels with a length ratio greater than 1 may be over-soluble. Therefore, a leaf bud index is obtained by weighting the 100 kernels of malt to comprehensively reflect the overall solubility of malt.

[0035] Preferably, the single particle crushing degree is calculated by the following formula:

[0036] Single particle grinding degree FD = [1-(Mresidual / Mtotal)] × 100%;

[0037] In the above, Mresidual is the total mass of whole grains, half grains and broken grains remaining in the sieve; Mtotal is the total mass of malt initially weighed.

[0038] Preferably, the single particle crushing degree is obtained by the following method:

[0039] Sample preparation: Weigh the malt sample and record its total mass as Mtotal;

[0040] Single grain crushing: Each grain of malt is placed in a centrifuge tube, steel balls are added, and the single grain malt is crushed using a grinder;

[0041] Observation of the degree of crushing: After the crushing is completed, observe the degree of crushing of the wheat kernels in the centrifuge tube. Well-dissolved wheat kernels will be in a fine powder state after crushing; ungerminated or insufficiently dissolved wheat kernels will have glassy or semi-glassy particles and cannot be completely crushed, and may leave large particles such as whole kernels or half kernels. Collect the centrifuge tubes that were not completely crushed and count the number of tubes with whole kernels and half kernels. The more tubes there are, the worse the dissolution uniformity.

[0042] Residue treatment: For wheat kernels that are not completely crushed, the whole kernels, half kernels, broken kernels, husks and wheat flour in the tube are collected and sieved into the sieve. Fine powder and small particles are sieved out, and large particles are retained on the sieve.

[0043] Weighing the residue: Collect all the whole grains, half grains and broken grains in the sieve into a weighing dish, weigh them and record the mass of the residue as Mresidue;

[0044] Calculation of the degree of pulverization: Based on the mass of the residue and the total number of tubes of whole grains and half grains, a comprehensive evaluation is performed to calculate the degree of pulverization of the single grain.

[0045] Preferably, each grain of malt is placed in a 2.0 ml centrifuge tube, a 7 mm diameter steel ball (stainless steel) is added, and the single grain of malt is pulverized using a high-throughput tissue grinder at a grinding frequency of 1000-1200 rpm / min and a grinding time of 30-40 seconds. For malt that is well soluble and easy to grind, such as malt obtained from two-row barley, the grinding frequency can be controlled at 1000 rpm / min and the grinding time can be 30 seconds; for malt that is difficult to dissolve and has hard grains that are difficult to grind, such as malt obtained from six-row barley or high-protein barley, the grinding frequency is increased to 1200 rpm / min and the grinding time is extended to 40 seconds;

[0046] Preferably, for wheat kernels that have not been completely pulverized, the broken kernels, husks, and wheat flour in the tube are collected on a 0.2 x 0.2 mm sieve, and the sieve is gently tapped to allow the wheat flour to fall into a collection box. Fine powder and small particles can pass through the 0.2 x 0.2 mm sieve, while large particles such as whole kernels and half kernels are retained on the sieve. These particles are considered the insoluble portion of the wheat kernels and are used to calculate the degree of pulverization.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The present invention provides a method for evaluating malt solubility. This method innovatively introduces the dual parameters of leaf bud index (morphological index) and single grain crushing degree (physical index), replacing the traditional multi-biochemical index detection system. This simplifies the evaluation process and enables rapid determination of malt solubility. Compared with traditional methods, the present invention has the following advantages:

[0049] (1) Streamlining the testing indicators: The six key testing indicators were reduced to two, namely the leaf bud index and the single grain crushing degree, replacing the original multi-indicator comprehensive evaluation and establishing a unified malt solubility index judgment standard;

[0050] (2) High detection efficiency: detection time is shortened from 36 hours to 3 hours; simple operation, no need for expensive precision instruments; detection costs are significantly reduced, making it more suitable for promotion and use in large-scale production;

[0051] (3) Strong representativeness: Compared with the group mean of mixed malt crushing in traditional testing, the evaluation results of single-grain testing can better reflect the actual dissolution degree of the malt grains, facilitate horizontal comparison between samples of different varieties or different batches of the same variety, and are more representative;

[0052] (4) High practicality: It is conducive to the timely adjustment of the malting process of the malt factory, convenient for the rapid formulation of the saccharification process of the brewery, improves production efficiency, and ensures the consistency of product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The present invention provides a comparison of the detection indicators of the traditional method and the method of the present invention. DETAILED DESCRIPTION

[0054] The following is a detailed and complete description of the technical solutions in specific embodiments of the present invention, with reference to the accompanying drawings. It should be understood that the described embodiments are merely partial implementations of the overall technical solution of the present invention, and are not exhaustive. All other embodiments derived by those skilled in the art based on the overall concept of the present invention are intended to fall within the scope of protection of the present invention.

[0055] The above technical solutions of the present invention and the determination and verification process of the technical solutions are as follows:

[0056] Step 1: Barley cleaning

[0057] (1) Primary selection: Use a wind-powered primary selection machine to remove larger impurities (stones, ropes, straw, sack pieces) and smaller impurities (sand, dust, etc.).

[0058] (2) Selection: Use an awn remover to remove wheat awns, an electromagnetic iron remover to remove iron debris, a stone remover to remove mixed stones, and a hole sorter to remove impurities from the wheat kernels. After processing, the barley / wheat used for feeding must be free of iron filings, earth, and other harmful inclusions. The purity rate of barley / wheat must be ≥99.5%.

[0059] (3) Grading: Thin wheat grains are removed through grading screens. The proportion of wheat grains with a belly diameter of less than 2.0 mm in the barley / wheat production feed shall not exceed 1.0%, in order to create conditions for uniform impregnation and germination, thereby improving the extraction rate of malt.

[0060] Step 2: Specific steps of malt preparation (1) Steeping: Taking Copeland as an example, a three-steeping and two-break steeping process is adopted. The water temperature of the steeping is controlled at 15-17℃. Continuous ventilation and oxygen supply are used during the steeping process, including the first steeping stage (wet steeping for 5 hours), the first break stage (dry steeping for 6 hours), the second steeping stage (wet steeping for 7 hours), the second break stage (dry steeping for 6 hours) and the third steeping stage (wet steeping for 4 hours), with a total duration of 28 hours. This process needs to be appropriately adjusted according to the barley variety to ensure that the final steeping degree reaches 40.5% and the germination rate exceeds 90%.

[0061] (2) Germination: The germination temperature is controlled at 16-18°C, and the germination time is 96 hours. The wheat should be turned over every 12 hours, and continuous ventilation and oxygen supply are required during the germination process. The fresh air usage is 80% within 24-36 hours of germination, and the fresh air usage is reduced to 60% for 48-72 hours, and further reduced to 50% for 72-96 hours.

[0062] (3) Drying: The green malt obtained in the above steps was transferred to a separate drying oven for ventilation and moisture removal. The drying process was: 50°C (5 hours) → 55°C (4 hours) → 65°C (4 hours) → 75°C (2 hours), then the temperature was raised to 84°C and roasted at a constant temperature for 3 hours.

[0063] (4) Root removal: After drying, wait for the malt to cool to room temperature and carry out root removal within 12 hours to obtain the finished malt.

[0064] Step 3: Testing of general malt quality indicators

[0065] 1. Crispness

[0066] (1) Instrument preparation: Install the brittleness tester in place, press the power switch button, and preheat for more than 30 minutes.

[0067] (2) Sample weighing: Use a plastic liter cup to weigh 50±0.01g of the cleaned malt sample and add it to the upper discharge funnel of the brittle meter. At the same time, place the collection box at the lower discharge port.

[0068] (3) Instrument operation: Move the control handle from the upper node to the lower node, press the operation switch, the operation indicator light flashes, and the instrument runs for 8 minutes.

[0069] (4) Stop operation: When the set time is reached, the instrument automatically stops. Move the control handle from the lower node to the upper node, remove the outer cover, press the copper button on the upper left corner, and remove the screen.

[0070] (5) Sample collection: Use a brush to collect the broken grains, husks, and wheat flour on the pressure roller into the sieve, and tap the sieve gently to allow the wheat flour that can pass through the sieve holes to fall into the collection box.

[0071] (6) Particle treatment: Collect all the particles in the sieve (use a hard brush to remove the particles in the sieve holes) into a plastic beaker and weigh them.

[0072] (7) Calculation of results: The friability calculation formula is: F = (100-2W) ÷ 100 × 100%, where: F (Friability) represents the friability of the sample, and W represents the weight of the remaining particles and husks in the sieve, in grams.

[0073] 2. Inventory value

[0074] (1) Determination of soluble nitrogen: Take two dry and clean digestion tubes, add 10 mL of wort to each, then add 2-3 drops of concentrated sulfuric acid to each, place them in a digestion furnace and carefully evaporate to dryness, then take them out for later use.

[0075] (2) Determination of total nitrogen: Accurately weigh 1 g of the finely powdered sample (accurate to 0.0001 g) and carefully add it to the digestive tube.

[0076] (3) Digestion and distillation: Process according to conventional digestion and distillation operations.

[0077] (4) Titration operation: Titrate the distillate with 0.1 mol / L hydrochloric acid standard solution, shaking the bottle while titrating and observing the color change until the color of the distillate changes from green to slightly red. This is the titration end point, and record the amount of hydrochloric acid consumed.

[0078] 3. Beta-glucan

[0079] (1) Sample preparation: Take three 25 ml stoppered colorimetric tubes and label them as follows: No. 1 (blank), No. 2 (sample), and No. 3 (sample). Tubes No. 2 and No. 3 are parallel samples.

[0080] (2) Solution addition: Accurately pipette 2 ml of distilled water into tube 1 (blank), and pipette 2 ml of the diluted sample into tubes 2 and 3 (samples) respectively.

[0081] (3) Constant temperature treatment: Place the three colorimetric tubes in a constant temperature water bath at (20±0.1)℃ and keep the temperature constant for 5 minutes.

[0082] (4) Color development reaction: Add 4 ml of Congo red solution kept at 20°C to the blank and sample colorimetric tubes respectively, shake well, start timing, and keep the temperature in a constant temperature water bath at (20±0.1)°C for 10 minutes.

[0083] (5) Colorimetric determination: After 10 minutes of incubation, immediately use a 10 mm glass cuvette to measure the absorbance of the sample at a wavelength of 550 nm, using a blank colorimetric tube as a reference.

[0084] Step 4: Development of single-kernel malt detection index and its operation steps

[0085] The present invention provides two detection indices for evaluating the solubility of single malt grains, namely the leaf bud index and the malt single grain crushing degree, aiming to achieve a rapid evaluation of malt solubility. The specific operation steps are as follows:

[0086] 1. Leaf bud index:

[0087] (1) Sample preparation: 100 grains of malt samples were placed in a beaker and about 100 ml of distilled water was added.

[0088] (2) Boiling treatment: Place the beaker on an electric stove and boil for 5-6 minutes, then cool at room temperature for 30 minutes.

[0089] (3) Observation and classification: After the wheat kernels cool down, the epidermis becomes transparent. The length of the leaf bud is observed through the epidermis and classified according to the ratio of the leaf bud length to the whole wheat kernel, which are 0-1 / 4, 1 / 4-1 / 2, 1 / 2-3 / 4, 3 / 4-1, and >1. For example, 0-1 / 4 refers to wheat kernels with no germination and a leaf bud length less than 1 / 4 (excluding 1 / 4), 3 / 4-1 refers to wheat kernels with a leaf bud length from 3 / 4 to 1 (including 1), and >1 refers to wheat kernels with a leaf bud length exceeding the length of the malt kernel.

[0090] (4) Calculation of leaf bud index:

[0091] The leaf bud lengths of malt samples were tested, and the calculation formula for the Acrospire Length Index (ALI) was determined by regression analysis of various leaf bud lengths and related dissolution indices, as follows:

[0092]

[0093] Among them, N1-N5 represent the number of malt grains with leaf bud lengths of 0 to 1 / 4, 1 / 4 to 1 / 2, 1 / 2 to 3 / 4, 3 / 4 to 1, and >1, respectively.

[0094] 2. Single particle crushing degree determination

[0095] The determination of single-grain crushing degree is an indirect assessment of malt solubility based on physical brittleness. A high-throughput tissue grinder is used to subject single malt grains to high-frequency impact treatment with steel balls. After crushing, the degree of crushing of the grains in the centrifuge tube is observed. Well-dissolved grains are easy to crush and form a fine powder after crushing; ungerminated or insufficiently dissolved grains contain glassy or semi-glassy particles that cannot be completely crushed, and may retain whole or half-grain malt. This method obtains the different crushing degrees of single-grain malt under the same frequency of steel ball impact by weighing and calculating the residue after crushing, and then determines the actual dissolution of each single grain of malt.

[0096] Single particle crushing degree determination includes:

[0097] (1) Sample preparation: Select 100 grains of malt sample and record their total mass (denoted as Mtotal).

[0098] (2) Single grain grinding: Place each grain of malt into a 2.0 ml centrifuge tube and add a 7 mm diameter steel ball (made of stainless steel). Use a high-throughput tissue grinder to grind the single grain of malt. The recommended grinding frequency is 1000-1200 rpm / min and the grinding time is 30-40 seconds.

[0099] (3) Observation of the degree of crushing: After the crushing is completed, observe the degree of crushing of the wheat grains in the centrifuge tube. Well-dissolved wheat grains are in a fine powder state after crushing; wheat grains that have not germinated or are insufficiently dissolved have glassy or semi-glassy particles and cannot be completely crushed, and whole grains or half-grains may remain. Summarize the centrifuge tubes that have not been completely crushed, and count the number of whole grain and half-grain tubes. The more tubes there are, the worse the dissolution uniformity.

[0100] (4) Residue treatment: For wheat grains that are not completely crushed, collect the broken grains, husks and wheat flour in the tube into a sieve with a pore size of 0.2×0.2 mm, and tap the sieve gently to make the wheat flour fall into the collection box.

[0101] (5) Weighing the residue: Collect all the whole grains, half grains and broken grains in the sieve into a weighing dish, weigh them and record the mass of the residue (recorded as Mresidue).

[0102] Calculation of the degree of fragmentation: Calculate the degree of fragmentation (FD) of a single particle based on the mass of the residue. The calculation formula is as follows:

[0103] Single particle grinding degree FD = [1-(M residual / M total)] × 100% (Formula 2)

[0104] Residual rate = Mresidual / Mtotal, crushing degree = 1-residual rate,

[0105] Wherein, FD is the single grain grinding degree, which indicates the degree of malt grinding; Mresidual is the total mass of whole grains, half grains and broken grains remaining in the sieve; Mtotal is the total mass of malt initially weighed.

[0106] 3. Calculation formula of malt solubility index

[0107] A total of 121 representative two-row barley malt samples, including commercial malt and micro malt, were collected from major barley producing regions worldwide, including Canada, Australia, France, Argentina, and China, and refrigerated for future use. The leaf bud index and single-kernel crushing degree of the samples were tested and analyzed, and a regression model was established to correlate the malt solubility index with the leaf bud index and single-kernel crushing degree.

[0108] Through linear regression analysis, the calculation formula of malt solubility index (Index of Modification, MI) was established:

[0109] MI=5.867-0.031×ALI-0.026×FD (Formula 3)

[0110] Among them, ALI: leaf bud index; FD: single grain crushing degree; the R-square value of the model is 0.893, indicating that the leaf bud index and single grain crushing degree can explain 89.3% of the variation of malt solubility index.

[0111] 4. Verification of method accuracy

[0112] To verify the accuracy and reliability of the proposed malt solubility index evaluation method, 48 additional batches of malt samples (16 batches of micro-malt and 32 batches of commercial malt) were selected for method validation. Correlation analysis was performed between traditional evaluation indicators such as crispness and β-glucan and the malt solubility index (MI) to determine the correlation coefficient and verify the accuracy and reliability of the method.

[0113] Verification steps (1) Routine indicator testing

[0114] Each batch of malt samples is tested for routine indicators, including crispness, saccharifying power, extract, storage value, α-amino nitrogen, and β-glucan. Currently, breweries mainly use crispness and coarse-fine powder difference to reflect the solubility of starch, storage value and FAN to reflect the solubility of protein, and β-glucan to reflect the degree of endosperm cell wall degradation.

[0115] (2) Malt solubility index evaluation

[0116] The malt solubility index of 48 batches of samples was evaluated simultaneously, including rapid detection of leaf bud index and single grain crushing degree, calculation of malt solubility index (MI), and evaluation of malt solubility.

[0117] (3) Correlation analysis

[0118] The correlation between the conventional indicators (crispness, storage value, β-glucan) and malt solubility index (MI) values ​​of 48 batches of malt samples was analyzed.

[0119] From the correlation analysis, it can be seen that the malt solubility index MI is significantly correlated with indicators such as β-glucan, storage value, and crispness, indicating that the malt solubility index can comprehensively reflect the starch solubility, protein solubility and cell wall solubility of malt, and comprehensively reflect the overall solubility degree of malt.

[0120] 5. Range of malt solubility and malt solubility index

[0121] According to the different solubility degrees of malt, the malt solubility index is defined as follows:

[0122] Good solubility: 0.50<MI≤1.00

[0123] Insufficient dissolution: 1.00<MI≤1.50

[0124] Poor solubility: MI>1.50

[0125] Comprehensive evaluation capability: The malt solubility index provides a more comprehensive and accurate method for evaluating malt solubility, solving the problems of traditional evaluation methods such as reliance on multiple indicators, cumbersome operations, and lack of unified standards.

[0126] Reliability Verification: Through the analysis and verification of a large number of malt samples, the reliability and accuracy of the malt solubility index have been fully demonstrated, which can provide strong support for malt quality control and production optimization.

[0127] In order to more clearly and in detail introduce the malt solubility evaluation method provided by the embodiments of the present invention, it will be described below with reference to specific examples.

[0128] Example 1

[0129] Use the malt solubility index to replace traditional testing methods and quickly adjust the malting process.

[0130] In theory, the quality indicators of barley of the same variety should be consistent, and the malting process and malt quality should also remain stable. However, as an agricultural crop, barley is subject to the influence of climate and soil, and its quality fluctuations are inevitable. Differences may also exist between batches of the same variety. In actual production, the production process must be adjusted promptly based on the quality of the barley and its malting properties to ensure consistent malt quality.

[0131] Malt, the main raw material for beer, is obtained from barley after soaking, germination, drying, and root removal. Generally, a single-round malting cycle is about 168 hours. After obtaining the malt, the malt quality analysis should be completed as soon as possible. If the indicators are qualified, it means that the malting process is suitable and production can continue. If the malt indicators are unqualified, the reasons need to be investigated and the production process needs to be adjusted in time to ensure that the malt quality is qualified. There are many conventional malt quality evaluation indicators, which have problems such as cumbersome operation, long testing cycle, and high cost. Malt factories usually implement continuous malting production with a feed volume of hundreds of tons. Traditional quality testing has a lag. By the time problems with malt quality are discovered, multiple batches of unqualified malt have already appeared, seriously affecting the consistency of product quality.

[0132] This patent proposes a method for evaluating malt solubility, innovatively introducing dual parameters of leaf bud index (morphological index) and single grain crushing degree (physical index), replacing the traditional multi-biochemical index detection system. The detection can be completed in only 3 hours, and can quickly evaluate malt solubility, saving 91.7% of the detection time compared with traditional methods. It can realize real-time adjustment of the malting process, especially the rapid optimization of soaking and germination processes.

[0133] Step 1: Malt solubility index evaluation to quickly adjust the malting process

[0134] The malting process of a shipload of Australian two-row barley, Spartacus, was tracked. The leaf bud index and single-kernel crushing degree of each batch of malt were tested. The solubility index was used to quickly determine malt solubility, enabling real-time adjustments to the large-scale production process. A total of 26 batches of malt samples were tracked, and the test results for some of the malt are shown in Table 2.

[0135] Table 2 Solubility evaluation of some batches of Australian Spartacus malt

[0136] index Standard range Batch 1 Batch 12 Batch 13 Batch 14 Batch 25 Batch 26 Leaf bud index ≥86 89 80 90 94 87 92 Single particle crushing degree ≥84 84 81 86 85 82 87 Solubility Index 0.50-1.00 0.92 1.28 0.84 0.78 1.04 0.75 Solubility evaluation / Good dissolution Insufficient dissolution Good dissolution Good dissolution Insufficient dissolution Good dissolution

[0137] Result analysis:

[0138] As shown in the table, 24 of the 26 batches of Spartacus malt had a solubility index below 1.00, indicating good solubility. Two batches had a solubility index greater than 1, indicating insufficient solubility. The solubility index for batch 12 was 1.28, with both the leaf bud index and single-kernel crushing below the standard range. The number of tubes containing whole and half kernels after single-kernel crushing was twice that of batch 11, indicating significant malt solubility deficiency, which was attributed to insufficient starch and protein dissolution. Upon discovering the anomaly, the malt mill promptly adjusted the malting process, extending the first steeping time by 2 hours and raising the germination temperature by 2°C between 24 and 72 hours to maximize the dissolution of the malt endosperm cells. Following these adjustments, the leaf bud index for batch 13 increased from 80% to 90%, the single-kernel crushing increased from 81% to 86%, and the malt solubility index decreased from 1.28 to 0.84, indicating normal malt solubility. As production continued, the malt dissolution index for batch 25 was 1.04, indicating low single-kernel grinding. The number of tubes for whole and half kernels after single-kernel grinding increased by 20% compared to batch 24, indicating insufficient starch dissolution. The malt plant further adjusted the malt steeping process, extending the third steeping time by 2 hours while keeping the germination temperature unchanged. After this adjustment, the single-kernel grinding index for batch 26 increased from 82% to 87%, and the malt dissolution index decreased from 1.04 to 0.75, returning to normal. This indicates that the process adjustments were effective.

[0139] Step 2: Routine malt quality evaluation and result verification

[0140] Later, the above 26 batches of malt were retested using conventional methods, and the results of the malt solubility index were verified using conventional test indicators to ensure the reliability of the malt solubility index. The test results of some batches are shown in Table 3.

[0141] Routine test results of 6 batches

[0142] Table 3 General quality indicators of Australian Spartacus malt

[0143] index Standard range Batch 1 Batch 12 Batch 13 Batch 14 Batch 25 Batch 26 Moisture% ≤4.5 4.1 3.8 4 4.1 4.5 4.5 Extract% ≥80.0 82.2 81.7 81.3 81.2 80.6 81.5 Saccharification power WK ≥240 307 316 314 303 307 277 Saccharification time min ≤10 8 9 9 8 10 9 Crispness% ≥80 97 74 97 94 75 88 Difference between coarse and fine powder% ≤1.5 1.1 1.3 0.8 0.7 1.4 0.8 Inventory value% 43.5±2 45.5 40.1 45.3 43.5 42.5 44.5 Amino nitrogen g / 100g 155±15 162 158 152 155 143 151 β-glucan mg / 100g ≤110 78 92 86 91 98 66 Filtering time Min ≤40 33 47 36 30 38 31 Total acid ml / 100ml ≤1.15 0.92 0.92 0.89 0.92 0.87 0.9 Chroma EBC 4.0±1.0 4.2 3.7 3.5 3.9 3.8 4.7 Boiling color EBC 8.0±1.0 7.8 7.8 7.6 7.7 7.9 7.8

[0144] Result analysis:

[0145] Analysis of conventional indicators revealed that 24 of the 26 batches of Spartacus malt had normal parameters and dissolved well. The 12th batch had a malt crispness of 74% and a storage value of 40.1%, indicating insufficient solubility of starch and protein, consistent with the results of the malt solubility index. The 25th batch had a malt crispness of 75%, below standard, indicating that starch solubility needs to be improved, consistent with the results of the malt solubility index.

[0146] Comparisons show that the malt solubility index yields essentially the same results as conventional indicators, but the testing time is reduced from 36 hours to 3 hours, a 91.7% reduction, and the testing cost is reduced by 95.8%. Multiple rounds of experiments have validated this method as accurate and reliable, effectively supporting real-time quality control in malt production. The malt solubility index has significant application value in adjusting production processes and ensuring malt quality.

[0147] Example 2

[0148] Use the malt solubility index to replace traditional testing methods to quickly adjust the saccharification formula and saccharification process.

[0149] Tracking the arrival of two new batches of purchased Canadian two-row barley malt, Copeland and Churchill. During the peak beer production season, malt indicators should be tested as soon as possible after entering the warehouse. Based on the malt's quality characteristics, a corresponding saccharification formula and saccharification process should be developed to ensure consistent beer quality.

[0150] Step 1: Use conventional malt quality evaluation to develop a mashing process

[0151] According to traditional methods, the two batches of malt were tested for routine malt indicators, including crispness, storage value, β-glucan and other solubility indicators. The testing of both batches of malt was completed within 36 hours.

[0152] The quality indicators of the two batches of malt are shown in Table 4.

[0153] Table 4 Conventional quality indicators of two batches of malt

[0154] project standard Copeland Churchill Moisture% ≤4.5 4.3 4.4 Extract% ≥80 81.0 81.1 Saccharification power WK ≥300 330 269 Saccharification time Min ≤10 9 9 Crispness% ≥80 88 75 Difference between coarse and fine powder% ≤1.5 1.1 1.3 Inventory value% 42.5±2 43.6 41.3 Amino nitrogen mg / 100g 160±15 165 151 β-glucan mg / 100g ≤110 65 98 Filtering time Min ≤40 30 33 Total acid ml / 100L ≤1.15 1.12 1.04 Chroma EBC 4.0±1 4.5 3.9 Boiling color EBC 8.0±1 8.5 7.5

[0155] Result analysis:

[0156] As can be seen from the table, Copeland malt meets the requirements for general indicators such as crispness, storage value, and β-glucan. Churchill malt falls below the standard in two key indicators: saccharification power and crispness. While indicators such as storage value and β-glucan meet the requirements, it suffers from insufficient starch solubility. Therefore, when formulating the saccharification process, it is possible to increase amylase activity by adding amylase preparations, or consider extending the saccharification time and lowering the saccharification temperature to promote starch solubility. In summary, different saccharification recipes were formulated based on the solubility characteristics of the two malts, as shown in Table 5.

[0157] Table 5 Saccharification formula and saccharification scheme 1

[0158] content comparison Test 1 Test 2 malt Existing malt Copeland Churchill Malt recipe Canadian wheat: Australian wheat 2:1 Canadian wheat: Australian wheat 2:1 Canadian wheat: Australian wheat 2:1 saccharification process 65℃60min 65℃60min 65℃70min

[0159] Since Copeland malt dissolves well, the saccharification process in Experiment 1 is consistent with the control. However, Churchill malt has low saccharifying enzyme activity, low brittleness, insufficient starch solubility, and average malt solubility. Therefore, when formulating the saccharification recipe, the saccharification time can be extended from 60 minutes to 70 minutes to enhance the effect of the enzyme. By tracking the subsequent saccharification process, it was found that after saccharification at 65°C for 60 minutes, the filtration time of the first wort was 70 minutes, and the turbidity of the cold wort was 0.5 EBC, indicating low saccharifying enzyme activity and slow speed. After extending the saccharification time to 70 minutes, the filtration time of the first wort was reduced to 60 minutes, the turbidity of the cold wort was reduced to 0.27 EBC, and other quality indicators of the wort were normal, indicating that the saccharification recipe and saccharification process were appropriately formulated and can meet the requirements of large-scale production.

[0160] Option 2: Use the malt solubility index instead of the traditional method to quickly develop the saccharification process

[0161] The leaf bud index and single grain crushing degree of two batches of malted Copeland and Churchill were tested respectively. The malt solubility was quickly determined based on the malt solubility index in just 3 hours, which is 91.3% shorter than the 36 hours of the traditional detection method.

[0162] The results of malt solubility index are shown in Table 6.

[0163] Table 6 Solubility index of two batches of malt

[0164] project standard Copeland Churchill Leaf bud index ≥86 88 87 Single particle crushing degree ≥84 87 81 Solubility Index 0.50-1.00 0.88 1.06 Solubility evaluation / Good dissolution Insufficient dissolution

[0165] Result analysis:

[0166] The results show that the Copeland malt solubility index was 0.88, indicating good solubility. However, the solubility index of the Churchill malt with added malt was 1.06, indicating insufficient solubility. Specific analysis revealed that the malt leaf bud index was normal, but the single-grain crushing degree was below standard. The number of tubes in whole and half grains was significantly higher than that of Copeland, indicating low solubility, indicating insufficient starch solubility. When formulating saccharification recipes and processes, starch solubility can be promoted by extending the saccharification time or adding enzyme preparations. Therefore, to address the issue of insufficient starch solubility in Churchill, saccharification plan 2 was developed, as shown in Table 7.

[0167] Table 7 Saccharification formula and saccharification scheme 2

[0168] content comparison Test 1 Test 2 malt Existing malt Copeland Churchill Malt recipe Canadian wheat: Australian wheat 2:1 Canadian wheat: Australian wheat 2:1 Canadian wheat: Australian wheat 2:1 saccharification process 65℃60min 65℃60min 65℃65-70min

[0169] Compared to the control, the mashing process for Experiment 1 with Copeland malt remained the same. However, due to slightly lower solubility in Churchill malt, the mashing time was increased by 10 minutes, and a thermostable amylase was added to promote full starch dissolution. Tracking the mashing process revealed normal wort quality indicators, indicating that the mashing recipe and process were appropriately formulated and met production requirements.

[0170] Comparative Analysis

[0171] Comparing the saccharification schemes given by the traditional method and the malt solubility index of the present invention, the saccharification formulas and saccharification process schemes formulated by the two methods are basically the same, but the detection time of the present invention is shortened by 91.3%, and production adjustments can be guided 33 hours in advance. The malt solubility index evaluation technology proposed in the present invention can play a good indicative role in the formulation of saccharification formulas and saccharification processes. In actual production, the single grain malt rapid evaluation technology can be used in conjunction with the traditional method to achieve complementary advantages. Judging from the performance of the subsequent large-scale production of wort and brewing process, the problem of insufficient dissolution of Churchill added malt was effectively solved by adjusting the saccharification formula and process, ensuring smooth saccharification and fermentation, and the final quality indicators of the finished wine met the requirements and the sensory evaluation was qualified.

[0172] In summary, the rapid malt solubility index evaluation technology proposed in this invention can quickly and accurately detect malt solubility, significantly shortening detection time and improving detection efficiency. Through rapid detection, factories can adjust malting and saccharification processes in real time, reducing the production of substandard products and ensuring product quality consistency. This method, combined with traditional detection methods, can better meet the needs of large-scale production and improve the overall efficiency and quality control level of malt production.

Claims

1. A method for evaluating malt solubility, characterized in that: Malt solubility is defined according to the malt solubility index. The lower the malt solubility index, the better the malt solubility. The malt solubility index is calculated by the following method: MI=5.867-0.031×ALI-0.026×FD; In the above formula, MI is the malt solubility index, ALI is the leaf bud index, and FD is the single grain grinding degree.

2. The malt solubility evaluation method according to claim 1, wherein When 0.50<MI≤1.00, the malt dissolves well; when 1.00<MI≤1.50, the malt dissolves insufficiently; when MI>1.50, the malt dissolves poorly.

3. The malt solubility evaluation method according to claim 1, wherein The leaf bud index is calculated by the following formula: In the above, N1, N2, N3, N4, and N5 represent the number of malt grains in which the ratio of leaf bud length to grain length is 0 to 1 / 4, 1 / 4 to 1 / 2, 1 / 2 to 3 / 4, 3 / 4 to 1, and >1, respectively.

4. The malt solubility evaluation method according to claim 3, wherein The leaf bud index is obtained by the following method: The malt samples were boiled, and after the grains cooled, the epidermis became transparent. The length of the leaf buds was observed through the epidermis, and the ratio of the leaf bud length of each grain of malt to the grain length was calculated. The malt was classified according to 0-1 / 4, 1 / 4-1 / 2, 1 / 2-3 / 4, 3 / 4-1, and >1, and the statistics obtained were N1, N2, N3, N4, and N5.

5. The malt solubility evaluation method according to claim 4, wherein: The leaf bud index is obtained by the following method: Sample preparation: Weigh 100 grains of malt sample, place them in a beaker, and add 100 mL of distilled water; Boiling treatment: Place the beaker on the electric stove, boil for 5-6 minutes, and cool at room temperature for 30 minutes; Observation and classification: After the wheat kernels are cooled, the skin becomes transparent. The length of the leaf buds is observed through the skin. The ratio of the leaf bud length to the length of the wheat kernel is calculated. The ratios are classified into 0-1 / 4, 1 / 4-1 / 2, 1 / 2-3 / 4, 3 / 4-1, and >1. The statistical results are N1, N2, N3, N4, and N5. Calculation of leaf bud index.

6. The method for evaluating malt solubility according to claim 1, wherein: The single particle crushing degree is calculated by the following formula: Single particle grinding degree FD = [1-(Mresidual / Mtotal)] × 100%; In the above, Mresidual is the total mass of whole grains, half grains and broken grains remaining in the sieve; Mtotal is the total mass of malt initially weighed.

7. The method for evaluating malt solubility according to claim 6, wherein: The single particle grinding degree is obtained by the following method: Sample preparation: Weigh the malt sample and record its total mass as Mtotal; Single grain crushing: Each grain of malt is placed in a centrifuge tube, steel balls are added, and the single grain malt is crushed using a grinder; Observation of the degree of crushing: After the crushing is completed, observe the degree of crushing of the wheat kernels in the centrifuge tube. Well-dissolved wheat kernels will be in a fine powder state after crushing; ungerminated or insufficiently dissolved wheat kernels will have glassy or semi-glassy particles and cannot be completely crushed, and may leave whole kernels or half-grain large particles. Collect the centrifuge tubes that were not completely crushed and count the number of tubes with whole kernels and half-grains. The more tubes there are, the worse the dissolution uniformity. Residue treatment: For wheat kernels that are not completely crushed, the whole kernels, half kernels, broken kernels, husks and wheat flour in the tube are collected and sieved into the sieve. Fine powder and small particles are sieved out, and large particles are retained on the sieve. Weighing the residue: Collect all the whole grains, half grains and broken grains in the sieve into a weighing dish, weigh them and record the mass of the residue as Mresidue; Calculation of the degree of pulverization: Based on the mass of the residue, the degree of pulverization of the single grain is calculated and a comprehensive evaluation is performed based on the total number of tubes of whole grains and half grains.

8. The method for evaluating malt solubility according to claim 7, wherein: Each grain of malt was placed in a 2.0 ml centrifuge tube, and a steel ball with a diameter of 7 mm was added. The single grain of malt was crushed using a high-throughput tissue grinder with a grinding frequency of 1000-1200 rpm / min and a grinding time of 30-40 seconds.

9. The method for evaluating malt solubility according to claim 7, wherein: For the wheat kernels that are not completely crushed, collect the whole kernels, half kernels, broken kernels, husks and wheat flour in the tube into a sieve with a pore size of 0.2×0.2mm, and tap the sieve gently to make the wheat flour fall into the collection box.

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