Beer with low in-vitro glycemic index and preparation method thereof

Abstract

The invention relates to the field of beer production, and discloses beer capable of reducing in-vitro glycemic index (GI) on the premise of maintaining typical flavor and a preparation method of the beer. On the basis of malt, hops and yeast, resistant dextrin which meets the requirements that DE is 8-20 and the number-average DP is 3-20 and contains an alpha (1-> 2) / alpha (1-> 3) bond is introduced; performing main fermentation until the weight loss of a unit volume sample is delta mmp; lt; and then adding 6 g / L glucose at 11 DEG C, and carrying out secondary fermentation for 14 days. AUC is measured through a DNS method (540 nm) according to an in-vitro digestion model, HI is converted, and GI is calculated according to the formula that GI = 39.71 + 0.548 * HI, and the obtained beer GI is smaller than or equal to 58; under a set caliber, the alpha-amylase (520 nm) and alpha-glucosidase (405 nm) have a high inhibition rate, and the foam retention, IBU and turbidity are kept in a contrast range. The method is clear in process, controllable in parameter and suitable for large-scale copying.

Description

Technical Field

[0001] This invention belongs to the field of beer production technology, and relates to a beer and its preparation method that reduces the in vitro glycemic index (GI) and increases the in vitro inhibition rate of two types of starch digestion-related enzymes while maintaining typical flavor. Background Technology

[0002] Beer is a fermented beverage with malt, hops, and yeast at its core. Its flavor and quality are determined by a combination of factors, including formulation, mashing process, hop addition, fermentation, and post-processing. Formulation and fermentation management alter residual sugar levels and sugar form distribution, thus affecting the exposure and release rate of hydrolyzable carbohydrates in vitro. For the quantitative evaluation of these effects, the industry commonly uses in vitro digestion models combined with the DNS method to obtain reducing sugar release at various time points, calculate the area under the curve (AUC), and obtain the hydrolysis index (HI). The in vitro glycemic index (GI) of the sample is then calculated using the empirical formula GI = 39.71 + 0.548 × HI to ensure comparability between different batches or products. To aid interpretation, the in vitro inhibition rates of α-amylase and α-glucosidase are often used as reference indicators of the formulation's impact on the starch / oligosaccharide hydrolysis process. While these methods are practical and verifiable in beverage evaluation, their application to beer systems requires consideration of the interference of alcohol and flavor matrices on color development and endpoint determination. To minimize differences in aperture, the following conventions are generally agreed upon: GI testing uses the DNSAUC / HI system and is measured at 540 nm; α-amylase inhibition rate is measured using DNS colorimetry at 520 nm; and α-glucosidase inhibition rate is measured using p-NPG as a substrate at 405 nm.

[0003] Existing technologies for reducing in vitro GI or slowing down in vitro hydrolysis rates generally follow four paths: (1) regulating sugar composition and fermentability through formulation and saccharification procedures; (2) regulating residual sugar and carbonation levels through fermentation management (such as primary fermentation endpoint determination, post-fermentation / secondary fermentation, etc.); (3) introducing dietary fiber / resistant polysaccharides to affect substrate accessibility or system viscosity; and (4) introducing the inhibition rates of two types of digestion-related enzymes in vitro as auxiliary indicators for formulation optimization. However, these paths are often constrained in beer systems by the trade-off between sensory acceptability and physicochemical boundaries (such as foam retention, bitterness value IBU, turbidity, and color). More commonly, there is a lack of uniformity among reports in terms of addition time, measurement units (such as the conversion between volume‰ and g / hL), fermentation endpoint determination methods, and statistical processing, leading to difficulties in cross-sectional comparisons and insufficient reproducibility of results.

[0004] Furthermore, the source and structural differences of resistant dextrin, which are optional formulation elements (such as the DE / DP range and α(1→2) / α(1→3) bond type composition), can significantly affect system performance. If the specifications of raw materials and their spectroscopic recording caliber are not clearly defined beforehand, batch-to-batch discrepancies may occur even with similar processes, increasing the difficulty of data interpretation and reducing the efficiency of verification during the review stage. At the same time, if the definition of control samples (whether functional components are added, whether secondary fermentation for sugar supplementation is performed, and whether the original wort concentration and fermentation procedure are consistent) are not standardized, it will directly affect the comparability of comparative data and the robustness of conclusions.

[0005] In summary, existing technologies generally suffer from the following weaknesses: inconsistent evaluation criteria, insufficient decoupling of formulation and process variables, lack of prior standardization in definitions and units of measurement, and lack of spectroscopic evidence for raw material structure indicators. Against this backdrop, it is practically necessary to construct an integrated, verifiable, and scalable standard encompassing formulation, process, and evaluation criteria for the beer system, in order to simultaneously achieve both a "low in vitro GI target" and "non-deteriorating sensory / physicochemical indicators." Summary of the Invention

[0006] Technical problems to be solved Without compromising the main sensory and physicochemical qualities of beer, a replicable brewing scheme integrating formula, process, and evaluation criteria was constructed. This scheme ensured that the resulting beer achieved a GI≤58 under a unified in vitro standard (DNSAUC / HI→GI=39.71+0.548×HI, measured at 540nm), and exhibited high inhibition rates against α-amylase and α-glucosidase in in vitro experiments. At the same time, key indicators such as foam retention, bitterness value (IBU), and turbidity remained within the control range.

[0007] Technical solution This invention provides a beer and a method for preparing the same, comprising the following steps: (1) The wort is prepared by crushing, gelatinizing, saccharifying, filtering, boiling and adding flocculants in stages, vortexing and cooling, using malt as the main raw material. (2) Add resistant dextrin that meets the specifications before inoculating yeast or after filtering the finished product as needed and mix well; (3) The primary fermentation was stopped when the weight loss per unit volume of sample Δm was less than 0.2 g / 100 mL; (4) Secondary fermentation is carried out to supplement sugar in order to achieve carbonation and post-ripening; (5) Filter and perform necessary finishing modifications to obtain the finished beer.

[0008] Preferred parameters: primary fermentation temperature 11°C; secondary fermentation 11°C × 14 days; sugar supplementation 6 g / L (calculated as glucose); resistant dextrin 1.5–2.0 wt%.

[0009] The resistant dextrin has a reducing sugar equivalent (DE) of 8–20 and a number-average degree of polymerization (DP) of 3–20, and contains at least one glycosidic bond selected from α(1→2) and α(1→3), preferably both. The relative peak areas of the two bonds and their sum are recorded according to the spectroscopic aperture of detection method 5. The total amount of hops added in segments is 150 g / hL (converted from volume mass of 20°C, granular hops, bulk density ρ=500 g / L; other formulations are converted accordingly). The primary fermentation endpoint is determined according to detection method 4; the in vitro GI is determined according to detection method 1 (DNSAUC / HI→GI=39.71+0.548×HI, 540 nm).

[0010] In this invention, "control beer" refers to a sample with the same wort concentration and fermentation process as the test sample, without the addition of resistant dextrin, and without secondary fermentation for sugar supplementation.

[0011] Beneficial effects Under the synergistic effect of the above-mentioned technical features, the performance of the present invention in engineering applications is mainly reflected in the following aspects; the following effects are for illustration only and do not constitute a limitation on the claims.

[0012] (1) In vitro GI is reduced and verifiable: Under the same standard, the GI of the representative sample is 55.49±1.23, which is lower than that of the control ordinary beer (64.25±1.67) and several commercially available samples (62.78–72.65), with significant differences (P<0.05); AUC / HI and the calculation process are shown and verifiable.

[0013] (2) Increased inhibition rates of two types of digestion-related enzymes: Under the condition of 1.5–2.0 wt% resistant dextrin, the inhibition rates of α-amylase were 41–56% and α-glucosidase were 6–12%, which were significantly higher than those of the control (P<0.05); when added to 3.7 wt%, the inhibition rates were approximately 77.51% and 13.87%, respectively (P<0.05).

[0014] (3) The main physicochemical and sensory indicators do not deteriorate: Under the program of 6g / L@11°C×14d, the sample's foam retention is not lower than that of the control, and the IBU and turbidity are not higher than those of the control; the comprehensive sensory score of the five dimensions of n=20 is not lower than that of the control.

[0015] (4) In vitro correlation support of animal models: Under the condition of uniform gavage volume and time point, the peak time of postprandial blood glucose in the sample group was extended from 15 min to 30 min, and the decline was more gradual; this article includes 120 min time point data to enhance the temporal integrity (this result is only used for methodological support and does not constitute a claim for medical use). Attached Figure Description

[0016] Figure 1Curves showing the effects of different beers on postprandial blood glucose in rats (0 / 15 / 30 / 60 / 90 / 120 min). Detailed Implementation

[0017] General Instructions and Raw Material Specifications The definition of a reference beer is: beer with the same original wort concentration and fermentation process as the test sample, without the addition of resistant dextrin, and without secondary fermentation for sugar replenishment.

[0018] Resistant dextrin specifications: DE 8–20, number-average DP 3–20, containing α(1→2) / α(1→3) bonds; the relative proportion of α(1→2)+α(1→3) is recorded according to spectroscopic methods (see detection method 5). The α(1→2) / α(1→3) bond type ratio and spectroscopic points of the corresponding batches are shown in Table 10.

[0019] Hop measurement standard: "3‰ (v / v) based on wort volume" is uniformly converted to a mass-volume ratio of 150 g / hL (20°C, bulk density of pellet hops ρ=500 g / L); other dosage forms or densities are converted according to the formula in General Note A and noted.

[0020] Determination of the primary fermentation endpoint: Weight loss per unit volume of sample Δm < 0.2 g / 100 mL (see detection method 4).

[0021] Methodology validation batches (A–D): These are internal process exploration samples used for statistical and methodological validation, not for mainline comparisons; their data are listed in Tables 6, 7, 5-continued, and 9, and are not used as comparison objects for the main conclusions of beneficial effects.

[0022] Detection methods Detection Method 1: In vitro digestion model and determination of GI Digestion was performed in the gastric and small intestinal phases using a phosphate buffer system: pepsin was added to the gastric phase, and after incubation at 37 °C, the pH was adjusted to 6.9 before entering the small intestinal phase; amylase was added, and the mixture was incubated at a constant temperature with shaking. Small intestinal sampling time points were 0 / 30 / 60 / 90 / 120 min; after enzyme inactivation at each time point, the mixture was treated with glucoamylase. Absorbance was measured at 540 nm using the DNS method, and reducing sugars were converted based on the glucose standard curve to calculate the hydrolysis rate. The AUC was calculated with hydrolysis time on the x-axis and hydrolysis rate on the y-axis. HI was converted from the AUC of the bread control curve, and the GI was calculated using GI = 39.71 + 0.548 × HI. Hydrolysis rate (%) = (reducing sugar release × 0.9 / dry matter mass) × 100.

[0023] Detection Method 2: Determination of α-amylase inhibition rate 1 U / mL α-amylase was used to react with potato starch substrate at 37 °C, followed by DNS color development (boiling water bath for 5 min), and the absorbance was measured at 520 nm. Let A2 (sample group), A0 (inactivated enzyme background), and A1 (blank control) be defined. The inhibition rate was calculated using the formula: Inhibition rate (%) = [1-(A2 - A0) / A1] × 100.

[0024] Detection Method 3: Assay for α-glucosidase inhibition rate Using p-NPG as a substrate, 0.25 U / mL α-glucosidase was added and incubated at 37 °C. The reaction was terminated with 0.2 mol / L Na₂CO₃. The absorbance was measured at 405 nm. Acarbose was used as a positive control, and the inhibition rate was calculated. Inhibition rate (%) = [1 - (A₂ - A₀) / (A₁ - A₀)] × 100.

[0025] Detection Method 4: Fermentation weight loss (determination of the primary fermentation endpoint) Using a container with an air valve, record the initial mass m0 and the liquid volume V; during fermentation, weigh the container mass mt periodically and calculate the weight loss per unit volume of sample Δm: Δm (g / 100 mL) = (m0 - mt) / V × 100.

[0026] The main fermentation is considered complete when Δm < 0.2 g / 100 mL is satisfied in two consecutive detection intervals.

[0027] Detection Method 5: Spectroscopic recording of α(1→2) / α(1→3) bonds in resistant dextrin The fingerprint region was obtained by 13C NMR (D2O, 25 °C) and HSQC, and GC-MS was performed as needed after methylation-hydrolysis-reduction-acetylation. The relevant peaks were deconvolved and normalized, and the relative peak area percentages of α(1→2) and α(1→3) and their sum were recorded.

[0028] Test Method 6: Basic Physicochemical Indicators Alcohol content, original wort concentration, foam retention (EBC method), bitterness value IBU (EBC / ASBC method), turbidity (EBC method), pH, etc., shall be performed in accordance with industry standards.

[0029] Test Method 7: Sensory Evaluation Recruit no fewer than 20 evaluators to score the appearance, aroma, texture, taste, and overall performance. Each item has a maximum score of 20 points, and the overall score is the sum of all items.

[0030] Example Example 1: Preparation of beer that can balance postprandial blood sugar (added before inoculation) The feed-to-water ratio was 1:4. After malting, the malt was mixed with 1.7 wt% resistant dextrin at 45 °C, incubated at 48 °C for 30 min, 63 °C for 60 min, 72 °C for 20 min, and 78 °C for 10 min, then filtered. The mixture was boiled for 60 min, and yeast was added in three portions, totaling 150 g / hL: half at the beginning, and 1 / 4 at 30 min and 50 min respectively. The wort was cooled and inoculated with brewer's yeast at a 1% inoculum rate, fermenting at 11 °C. Primary fermentation was stopped when Δm < 0.2 g / 100 mL. The mixture was transferred to a brown glass bottle, 6 g / L glucose was added, and a secondary fermentation was carried out at 11 °C for 14 days. Sample I was obtained by filtration.

[0031] Example 2: Preparation of beer that can balance postprandial blood sugar (added after adjusting the original wort) The wort was prepared according to the procedure in Example 1. The original wort concentration was adjusted to 10.5 °P and 1.7 wt% resistant dextrin was added. The inoculum was 1% and fermented at 11 °C until Δm < 0.2 g / 100 mL. The mixture was then transferred to a bottle, 6 g / L glucose was added, and the mixture was fermented again at 11 °C for 14 days. The mixture was then filtered to obtain sample II.

[0032] Example 3: Preparation of beer that can balance postprandial blood sugar (added after filtration) The sample was prepared according to the procedure in Example 1, and after secondary fermentation and filtration, 1.7 wt% resistant dextrin was added after filtration of the finished product to obtain sample III.

[0033] Example 4 (Control): Preparation of regular beer The same saccharification and boiling procedure as in Example 1 was followed, with a total floret addition of 150 g / hL in three stages (divided into 1 / 2, 1 / 4, and 1 / 4 portions). A 1% inoculum was used, and primary fermentation was carried out at 11 °C until Δm < 0.2 g / 100 mL, followed by direct cold storage for post-maturation. No resistant dextrin was added, and no secondary fermentation was performed for sugar replenishment. The control beer was obtained by filtration.

[0034] Example 5: Digestive enzyme inhibition experiment The inhibition rates of different samples were measured according to detection methods 2 and 3, and statistical analysis was performed (P<0.05 was considered significant). The original and summary results of the α-amylase and α-glucosidase inhibition rates of each sample are shown in Tables 3 and 4; the significance test is shown in Table 9.

[0035] Example 6: Effect of resistant dextrin addition on indicators Based on the process in Example 2, the amounts of resistant dextrin added were 1.7%, 2.2%, 2.7%, 3.2%, and 3.7 wt%, respectively, yielding samples 1–5. These samples were then measured and evaluated according to detection methods 2, 3, and 7. The inhibition rates of the two enzymes and sensory results for the gradient samples are shown in Tables 3, 4, and 7; the significance test is shown in Table 9.

[0036] Example 7: Comparison of physicochemical properties and glycemic index (GI) with commercially available beer The preferred sample obtained in Example 6 was selected and subjected to basic physicochemical analysis (see Table 6) and in vitro GI determination, along with the control beer and four commercially available beers with similar original wort concentrations. GI was measured at 540 nm using detection method 1, with sampling at 0 / 30 / 60 / 90 / 120 min. The AUC / HI was calculated and converted using GI = 39.71 + 0.548 × HI. The results are shown in Table 5-continued.

[0037] Example 8: Postprandial blood glucose response experiment in rats Animal experiments were conducted in accordance with ethical approval requirements. Twenty-four SD rats were randomly divided into four groups (n=6), and each rat was administered a gavage of 20 mL / kg. Blood glucose levels were monitored at 0, 15, 30, 60, 90, and 120 min, and curves were plotted. The control group was administered regular beer by gavage; the three L / M / H groups were administered the L / M / H sample of this invention by gavage, respectively. Results are shown below. Figure 1 See Table 8.

[0038] Research and Development Record Forms (Tables 1–10) To facilitate verification and scale-up, the specifications of raw materials and excipients, brewing batch records, raw / summary data of two enzyme inhibition and GI, statistical tests and resistant dextrin bond type spectroscopic records are shown in Tables 1–10.

[0039] Table 1 Raw Material and Auxiliary Material Specification Registration Form Table Note: Indicators are based on supplier COA; unless otherwise noted, units are indicated in the column headings.

[0040] Table 2 Brewing Batch Record Sheet Note: Hop addition is uniformly expressed in g / hL; α-acid percentage is as stated by the supplier; °P is the original wort concentration.

[0041] Table 3 Raw data from the α-amylase inhibition experiment (mean ± SD) Note: Absorbance was measured at 520 nm; inhibition rate and grouping are given in "Detection Method 2"; values ​​are mean ± SD. Table 4. Raw data from the α-glucosidase inhibition experiment (mean ± SD) Note: Inhibition rate and grouping are described in "Detection Method 3"; substrate is p-NPG; values ​​are mean ± SD. Table 5 Raw data from in vitro GI assays (single sample example) Note: The calculation caliber of GI is given in "Detection Method 1" (DNS-AUC / HI→GI=39.71+0.548×HI). Table 5 - Continued Calculations and Results Summary Note: Results are expressed as mean ± SD; significance tests are shown in Table 9. Table 6 Basic Physicochemical Indicators Note: Foam retention and turbidity are measured according to the EBC method; IBU is measured according to the EBC / ASBC method; the rest are measured according to industry standard methods. Table 7 Sensory Evaluation (Total Score 100) - Summary of Average Scores (n=20) Note: Rating dimensions are shown in the column headings; panel n=20; statistical tests are shown in Table 9. Table 8. Animal experimental groupings and blood glucose data (mean ± SD) Table Note: Results are mean ± SD; this table is used to support methodological consistency and does not involve claims of medical use. Table 9. Statistical test results (one-way ANOVA + Tukey HSD, α=0.05) Note: Significance threshold α = 0.05; Tukey HSD was used for multiple comparisons; complete raw data can be found in the relevant tables. Table 10. Ratio of bond types in resistant dextrins (spectral record) Note: For spectroscopic recording standards, see "Detection Method 5". General Note A: Conversion from 3‰ (v / v) to g / hL 3‰ (v / v) refers to the volume of hops being 0.3% of the wort volume. In 1 hL (=100 L) of wort, the hop volume V_hop = 0.003 × 100 = 0.3 L. Mass-volume conversion: g / hL = V_hop(L) × ρ(g / L) = 0.3 × ρ. Assuming 20 °C pellet hops (ρ = 500 g / L): 3‰ (v / v) = 150 g / hL. Other formulations (such as cone hops, T45 pellets) should be converted accordingly and noted.

[0042] Terms and Abbreviations GI: Glycemic Index; HI: Hydrolysis Index; DNS: 3,5-Dinitrosalicylic Acid Method; IBU: Bitterness Value; EBC: European Beer Council; ASBC: American Society of Brewing Chemists; HSQC: Heteronuclear Single Quantum Correlation Spectroscopy; p-NPG: p-Nitrophenyl-α-D-Glucoside.

[0043] Industrial applicability The method of this invention is based on conventional brewing equipment and common auxiliary materials. The process steps are clear, the parameters are controllable, and it is easy to scale up and replicate. By controlling the timing of addition, the fermentation endpoint, and the secondary fermentation, a low in vitro GI and a high inhibition rate of two digestion-related enzymes are obtained while maintaining flavor and physicochemical boundaries, which has industrial application value.

[0044] Terms and Abbreviations GI: Glycemic Index; HI: Hydrolysis Index; DNS: 3,5-Dinitrosalicylic Acid Method; IBU: Bitterness Value; EBC: European Brewers Association; ASBC: American Society of Brewing Chemists.

Claims

1. A beer made from malt, hops, yeast, and resistant dextrin; wherein the resistant dextrin has a reducing sugar equivalent of 8–20 and a number-average degree of polymerization of 3–20, and contains α(1→2) and / or α(1→3) glycosidic bonds; the in vitro glycemic index (GI) of the beer is determined by the 3,5-dinitrosalicylic acid method (540 nm) according to an in vitro digestion model and calculated according to the formula GI=39.71+0.548×HI based on AUC and HI, and the glycemic index (GI) of the beer is ≤58.

2. The beer according to claim 1, wherein, The resistant dextrin has a mass fraction of 1.5% to 2.0% in the finished product.

3. The beer according to claim 1, wherein, The resistant dextrin has a reducing sugar equivalent of 10–18 and a number-average degree of polymerization of 4–15.

4. The beer according to claim 1, wherein, The sum of the relative peak areas of α(1→2) and α(1→3) glycosidic bonds, as measured by nuclear magnetic resonance and related two-dimensional spectroscopy, is 20%–30%.

5. The beer according to claim 1, wherein, The total amount of hops added was 150 g / hL, and it was added in three batches at the beginning of boiling, 30 min after boiling, and 50 min after boiling, with the proportions of the three additions being 1 / 2, 1 / 4, and 1 / 4 respectively.

6. The beer according to claim 1, wherein, Under the following in vitro test conditions, the inhibition rates of α-amylase and α-glucosidase were 40%–60% and 6%–12%, respectively: α-amylase was measured at 520 nm using the DNS method; α-glucosidase was measured at 405 nm using p-NPG as a substrate.

7. A method for preparing beer, comprising: a) Prepare wort from malt and perform segmented sporulation; b) Add resistant dextrin before yeast inoculation or after filtration of the finished product, wherein the resistant dextrin has a reducing sugar equivalent of 8 to 20, a number-average degree of polymerization of 3 to 20, and contains α(1→2) and / or α(1→3) glycosidic bonds; c) Primary fermentation at 11 °C until the weight loss per unit volume of sample Δm < 0.2 g / 100 mL; d) Add 6 g / L glucose to the beer and carry out secondary fermentation at 11 °C for 14 days; e) Filter to obtain the finished beer; The GI of the resulting beer, calculated according to the test caliber described in claim 1, is no greater than 58.

8. The method according to claim 7, wherein, The resistant dextrin is added at a mass fraction of 1.5–2.0%.

9. The method according to claim 7, wherein, The total amount of floret added in step a) is 150 g / hL, and it is added in three parts at the beginning of boiling, 30 min after boiling, and 50 min after boiling. The proportions of the three additions are 1 / 2, 1 / 4, and 1 / 4 respectively.

10. The method according to claim 7, wherein, The resulting beer has a GI of 50–58.

Images