A beer brewing process of chlorella pyrenoidosa

Abstract

The application discloses a beer brewing process of chlorella pyrenoidosa, and comprises the following steps: crushing pale ale malt, performing saccharification, filtering and washing the saccharified wort to obtain wort; boiling the wort, adding hops, sea salt and coriander seeds in a boiling state, cooling, spinning, oxygenating, inoculating activated beer yeast, adding chlorella pyrenoidosa powder, performing primary fermentation; adding glucose after the primary fermentation, performing secondary fermentation, storing after maturation at low temperature, and obtaining a finished product. The beer product obtained by the process has significantly enhanced flavor, greatly improved antioxidant activity, excellent physical and chemical indexes, good product stability, and effectively solves the problem of algal fishy smell caused by the addition of chlorella. In addition, the application establishes a clear and scalable process path, the process operation is simple, can be conveniently implemented on the existing beer brewing equipment without additional modification, and provides a reliable technical scheme for developing new functional beer.

Description

Technical Field

[0001] This invention belongs to the field of beer brewing technology, specifically relating to a functional beer brewing process that significantly enhances the flavor characteristics and antioxidant activity of beer by adding Chlorella proteinensis. Background Technology

[0002] As one of the world's most consumed fermented alcoholic beverages, beer has enormous market value. In recent years, with the upgrading of health consumption concepts, functional craft beer, which combines nutritional benefits with distinctive flavors, has become a hot spot for industry innovation. However, traditional beer generally suffers from shortcomings such as low nutritional value, weak antioxidant activity, and homogenized flavors, making it difficult to meet consumers' demands for healthier and more diversified beverages.

[0003] Chlorella pyrenoidosa is a nutrient-rich and safe single-celled green algae, rich in polyphenols, flavonoids, polysaccharides, and other bioactive components. It possesses antioxidant, anti-inflammatory, and free radical scavenging functions, showing promising application prospects in the food and beverage industry. However, the research and application of chlorella in beer brewing is still in its early stages. In existing brewing processes, the effects of the addition stage, method, and dosage of chlorella on the physicochemical stability, retention rate of active ingredients, flavor characteristics, and sensory quality of beer are unclear, and a systematic process optimization and quality evaluation system is lacking. In particular, how to avoid undesirable flavors from chlorella (such as a fishy taste) and harmonize it with the complex flavor system of beer remains a key bottleneck restricting the improvement of chlorella beer quality and its industrial application. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a brewing process for Chlorella proteinensis beer, which, by adjusting the addition parameters of Chlorella, simultaneously and significantly improves the beer's antioxidant activity, the variety of characteristic flavor substances, and sensory purity.

[0005] To achieve the above results, the present invention adopts the following technical solution:

[0006] A brewing process for Chlorella proteinaceae beer, characterized by the following steps:

[0007] 1) Soak the light-colored ale malt in water and then grind it, controlling the degree of grinding so that the ground malt is generally coarse powder with an intact husk rate of ≥80%;

[0008] 2) The crushed malt is saccharified in stages at 45-78℃ with a material-to-water ratio of 1:3. The saccharified mash is then filtered and washed to obtain wort.

[0009] 3) Boil the wort, and while it is boiling, add bitter hops, aroma hops, sea salt and coriander seeds in stages. After boiling, adjust the wort concentration to 11-13°P.

[0010] 4) After cooling the wort, allow it to settle by vortexing. Transfer the clear wort from the top to a sterile fermentation vessel for aeration. After aeration, inoculate with activated brewer's yeast and simultaneously add sterilized Chlorella vulgaris powder. Initiate primary fermentation at 18–20°C. The primary fermentation is terminated when the apparent sugar content drops to 3.8–4.2°P and does not decrease further for two consecutive days. The amount of Chlorella vulgaris powder added is 1% of the malt mass.

[0011] 5) After the primary fermentation is completed, glucose is added and bottled for secondary fermentation. After low-temperature storage and ripening, the finished product is obtained.

[0012] Further, the heating saccharification process in step 2) above is as follows: the crushed malt is added to water at a material-to-water ratio of 1:3, the protein is first kept at 45°C for 30 minutes, and then the temperature is increased to 66°C at a rate of 1-1.5°C / min and kept at that temperature for at least 60 minutes for saccharification. After the iodine test is qualified, the temperature is increased to 78°C and kept at that temperature for 5 minutes to end the saccharification.

[0013] Further, the filtration and slag washing process in step 2) above is as follows: the mashed mash is pumped into the filter tank and filtered using the slag layer as the natural filter medium. The initial turbid wort is refluxed until it becomes clear, and the first wort is collected. Then, 78°C slag washing water is introduced in batches to wash the slag, with a total washing time not exceeding 90 minutes. The washing is stopped when the concentration of the slag residue drops to 1.0-1.5°P. The first wort and the slag washing wort are collected and combined, and the concentration of the combined wort is adjusted to 11°P.

[0014] Furthermore, in step 3) above, the wort is boiled and kept boiling for 75 minutes; the bitter hops are added 10 minutes after boiling, the aromatic hops are added 60 minutes after boiling, and the sea salt and coriander seeds are added 65 minutes after boiling.

[0015] Further, in step 4) above, the cooling treatment of the wort is as follows: the wort is cooled to 20°C using an ice water bath; the settling and vortexing time is 30 minutes; the oxygenation treatment is as follows: sterile air is introduced into the wort until the dissolved oxygen content of the wort reaches 8-10 mg / L, and the oxygenation is completed within 10-15 minutes.

[0016] Furthermore, in step 5) above, the amount of glucose added is 4g / L, and after bottling, it is stored at 18°C ​​in the dark for 10 days for secondary fermentation, and then refrigerated at 4°C for post-ripening.

[0017] Furthermore, in step 1) above, the proportion of coarse endosperm powder in the pulverized malt is 40% to 45%, and the proportion of fine powder is no more than 20%.

[0018] The beneficial effects of this invention are as follows:

[0019] 1) Significantly enhanced flavor: This invention effectively introduces characteristic terpenoid flavor substances, such as neroli terpenol (with elegant floral and woody aroma) and humulenol-II (with typical hop aroma), which are not detected in traditional ale beer, by adding a specific amount of Chlorella proteoglycans at the same time as yeast during the fermentation stage. Moreover, the three characteristic alcohols (linalool, neroli terpenol, and humulenol-II) can coexist synergistically, forming a complex, harmonious, and richly layered flavor system with the esters and alcohols already present in beer, significantly improving the sensory quality of beer.

[0020] 2) Significantly enhanced antioxidant activity: The Chlorella beer produced by the process of this invention has significantly higher total phenolic and total flavonoid content than the control group. Specifically, the total phenolic content of the Chlorella beer produced by the process of this invention can reach 498.19 mg GAE·L⁻¹. -1 The total flavonoid content reached 175.88 mg RE·L. -1 These figures represent increases of 60.4% and 51.1% respectively compared to the control group. Correspondingly, DPPH and ABTS... + The ability to scavenge free radicals is also significantly improved;

[0021] 3) Excellent physicochemical properties and good product stability: This invention, through a unique Chlorella addition process, avoids problems such as decreased alcohol content and excessive diacetyl content that may occur during saccharification or boiling. This invention quantitatively adds Chlorella during the fermentation stage, resulting in a 38.9% increase in alcohol content compared to the control group, while controlling the diacetyl content, a key off-flavor substance, to 0.11 mg·L⁻¹. -1 The levels are significantly lower than the national standard limits, ensuring the pure taste and fermentation stability of the beer;

[0022] 4) Overcoming the sensory defects of Chlorella application: This invention effectively solves the problem of algae odor caused by the addition of Chlorella. By adding it simultaneously with yeast during the fermentation stage, the flavor substances produced by Chlorella are integrated with the yeast metabolites, and the final product has no unpleasant flavor (including algae odor). The sensory score is the highest among all treatment groups, and the overall sensory quality is excellent.

[0023] 5) A clear and scalable process route has been established: Based on a systematic study of the timing and dosage of Chlorella addition, this invention has developed unique Chlorella addition process parameters and methods. This process is simple to operate and can be easily implemented on existing beer brewing equipment without additional modifications, providing a reliable technical solution for developing new functional beers. Attached Figure Description

[0024] Figure 1 Radar charts for multi-dimensional evaluation of the sensory quality of Chlorella beer prepared in each embodiment. Detailed Implementation Plan

[0025] The invention's technical solution will be further explained below with reference to specific embodiments.

[0026] Example 1

[0027] 1) Weigh out light-colored ale malt, spray with an appropriate amount of brewing water to moisten it, and then crush it with a grinder. Control the degree of crushing so that the crushed malt is generally coarse powder, and the husks are kept intact but not broken. The husk integrity rate is ≥80%, of which coarse powder accounts for 45%, fine powder accounts for 20%, there are no whole malt grains left, and the rest are husk fragments and medium-sized endosperm particles.

[0028] 2) Slowly add the crushed malt to 50℃ hot water at a material-to-water ratio of 1:3. After the system temperature naturally reaches 45℃ after addition, keep it at this temperature for 30 minutes to allow protein rest. After protein rest, raise the temperature to 66℃ at a rate of 1-1.5℃ / min and keep it at this temperature for at least 60 minutes for saccharification. During this time, perform an iodine test. After passing the iodine test, raise the temperature to 78℃ and keep it at this temperature for 5 minutes to end saccharification. Pump the saccharified mash obtained from saccharification into a filter tank and filter it using the washer layer as the natural filter medium. Recirculate the initial turbid wort until it becomes clear and collect the first wort. When the washer surface is exposed, wash the washer in batches with 78℃ washer water, with a total washing time not exceeding 90 minutes. Stop washing the washer when the concentration of the washer residual liquid drops to 1.5°P. Collect and combine the first wort and the washer wort. Adjust the concentration of the combined wort to 11°P by adjusting the amount of washer water or adding water.

[0029] 3) Bring the wort to a boil and keep it boiling for 75 minutes. Add bitter hops (Tsingtao hops) 10 minutes after boiling, add aroma hops (Saz hops) 60 minutes after boiling, and add sea salt and coriander seeds 65 minutes after boiling. After boiling, measure and adjust the wort concentration to 12°P.

[0030] 4) Cool the wort to 20°C using an ice-water bath. After cooling, allow the wort to settle in a fermentation vessel for 30 minutes to allow the heat-coagulated material and hops to settle completely. After settling, transfer the clear wort from the top to a sterile fermentation vessel and aerate it with sterile air for 15 minutes to achieve a dissolved oxygen content of 10 mg / L. After aeration, when the wort temperature drops to 16°C, inoculate with activated English ale yeast (Femandis S-04). Simultaneously, while stirring, evenly add sterilized Chlorella vulgaris powder (1% of the malt mass) for primary fermentation. Main fermentation temperature is controlled between 18 and 20°C. During fermentation, monitor the wort sugar content (°P) and specific gravity regularly. Primary fermentation ends when the wort sugar content drops to 4.0°P and does not decrease further for two consecutive days. In this example, the primary fermentation time is 7 days.

[0031] 5) After the primary fermentation is completed, the product is cold-stored, glucose is added at a rate of 4g / L, and after bottling, it is stored at 18℃ in the dark for 10 days for secondary fermentation. After that, it is refrigerated at 4℃ for post-fermentation to obtain the finished Chlorella beer.

[0032] Example 2

[0033] This embodiment is basically the same as the process in embodiment 1, except that in step 4), the amount of Chlorella proteinensis powder added is 0.5% of the malt mass.

[0034] Example 3

[0035] This embodiment is basically the same as the process in embodiment 1, except that in step 4), the amount of Chlorella proteinensis powder added is 1.5% of the malt mass.

[0036] Example 4

[0037] This embodiment serves as a blank group, and the process is basically the same as that in Example 1, except that no Chlorella powder is added in step 4).

[0038] Example 5

[0039] This embodiment is basically the same as the process in embodiment 1, except that: the Chlorella proteinensis powder is added in step 3), specifically 65 minutes after boiling, along with sea salt and coriander seeds, and the amount added is 1% of the malt mass.

[0040] Example 6

[0041] This embodiment is basically the same as the process in embodiment 1, except that: the protein-core Chlorella powder is added in step 2), specifically before saccharification, together with the pulverized malt, and the amount added is 1% of the malt mass.

[0042] Example 7

[0043] This embodiment is basically the same as the process in embodiment 1, except that: the Chlorella proteinensis powder is added after the main fermentation in step 4), and the amount added is 1% of the malt mass. After stirring evenly, the secondary fermentation and post-ripening are carried out according to step 5) of embodiment 1.

[0044] Example 8

[0045] The physicochemical properties, bioactive components, antioxidant activity, volatile flavor compounds, and sensory qualities of the beer products obtained in Examples 1-7 were systematically analyzed. The results are shown in Tables 2, 3, and 4. Figure 1 .

[0046] 1) Physicochemical index determination: The alcohol content, diacetyl and other indexes were determined in accordance with GB / T 4927-2008 "Analytical Methods for Beer".

[0047] 2) Determination of total phenol content: The Folin-Ciocalteu method was used.

[0048] 3) Determination of total flavonoid content: The aluminum nitrate colorimetric method was used.

[0049] 4) Anthocyanin content determination: pH differential method was used for determination.

[0050] 5) Antioxidant activity assay: DPPH and ABTS were used. + Free radical scavenging rate method.

[0051] 6) Determination of volatile flavor compounds: Solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) was used.

[0052] 7) Sensory evaluation: Ten professional wine tasters will give a comprehensive score based on four aspects: appearance, foam, aroma, and taste (out of 100 points). See Table 1 for the scoring criteria.

[0053] Table 1 Sensory Evaluation Criteria for Chlorella Beer

[0054]

[0055] The physicochemical and active ingredient determination results showed that the product of Example 1 exhibited the best overall performance in terms of physicochemical stability, bioactive components, and sensory quality. Specifically, as shown in Table 2: Compared to Example 4 (blank), Example 1 showed a 38.9% increase in alcohol content, and increases in total phenols and total flavonoids by 60.4% and 51.1%, respectively. The total phenols, total flavonoids, and sensory scores of Examples 2 and 3 were all lower than those of Example 1, indicating that there is a critical suitable range for the amount of Chlorella added, and the increase is not linear.

[0056] Although Example 5 had a high total flavonoid content, its diacetyl content reached 0.21 mg·L⁻¹.-1 It significantly exceeds the national standard limit (0.15 mg·L⁻¹). -1 Example 6 has the highest alcohol content and also higher total phenol and total flavonoid content, but due to poor flavor coordination, its overall sensory score is significantly lower than that of Example 1.

[0057] The diacetyl content in Example 7 was the lowest among all groups. Although the alcohol content, total phenols, and total flavonoids were higher than those in Example 4, they were all significantly lower than those in Example 1. The key characteristic terpenoid alcohols (linalool, nerolidol, and humulene-II, see Table 3) were not detected, and the sensory score was only 53.5 points, the lowest among all groups. It had a distinct algal fishy smell. The results of this group indicate that the addition of Chlorella after the main fermentation missed the active window period of synergistic metabolism between yeast and Chlorella, resulting in the inability to generate flavor substances and the inability of fishy substances to be metabolized and decomposed by yeast.

[0058] Regarding antioxidant activity, Example 1 showed a DPPH free radical scavenging rate of 78.4%, and ABTS... + The free radical scavenging capacity is 3.21 mg GAE·L⁻¹ -1 All values ​​were at a high level, indicating significant in vitro antioxidant activity. Example 2 showed the highest DPPH radical scavenging rate (83.80%) among all groups, but its total phenol and total flavonoid content were lower than that of Example 1, indicating that the antioxidant activity is not a simple linear relationship with the total phenol / total flavonoid content. It is also related to the effects of other antioxidant components (such as carotenoids and polysaccharides in Chlorella) and the dissolution efficiency of components under different processing conditions. Example 5 showed a relatively low DPPH radical scavenging rate of 65.94%, although its total flavonoid content was high, reaching 215.70 mg RE·L⁻¹. -1 However, high diacetyl content and the presence of heat-induced deteriorators such as furfural can negatively impact the utilization of antioxidant components. Example 7: DPPH and ABTS + All were lower than in Example 1, further proving that the antioxidant components of Chlorella were not fully released and converted after the main fermentation was completed.

[0059] Table 2 Comparison of key physicochemical and active ingredient indicators of beer products in various embodiments

[0060]

[0061] The results of flavor compound determination are shown in Tables 3 and 4. In Example 1, three characteristic terpene flavor compounds—linalool, nerolidol, and humulenol-II—were detected, along with a rich variety of esters. Alcohol flavor compounds were almost undetectable in Examples 2, 4, and 7. While Example 5 contained characteristic terpene flavor compounds and esters, it also contained carbonyl compounds such as 2-methyl-10-undecenal, 2-undecenal, and furfural, which affect beer flavor. Furfural is a flavor compound associated with beer aging and deterioration, contributing a stale taste and severely impacting the purity of the beer flavor. Although Example 6 contained a relatively rich variety of flavor compounds, its overall flavor harmony was inferior to that of Example 1, and it also contained the deteriorating flavor compound furfural.

[0062] Table 3. Volatile flavor compounds in beer products from each embodiment.

[0063]

[0064] Note: "✓" indicates detected, "ND" indicates not detected.

[0065] Table 4 Comparison of key indicators of beer products in each embodiment

[0066]

[0067] The sensory evaluation comparison results of products in Examples 1-6 are as follows: Figure 1 As shown, Example 1 performed excellently in aroma, taste, and foam, with no algae-like odor, achieving the highest score of 85.7 (see Table 2). Example 5 suffered from flavor degradation due to high diacetyl content and carbonyl compounds such as furfural. Although Example 6 scored highly in appearance, the addition of Chlorella during the saccharification stage resulted in prolonged heat exposure, leading to the detection of heat-induced deterioration substances such as furfural. Furthermore, characteristic flavor compounds such as humulene-II and nerolidol did not fully synergize with yeast metabolites, resulting in overall flavor harmony inferior to Example 1, and a significantly lower overall sensory score. Example 2 received a significantly lower sensory score than Example 1, specifically exhibiting a thinner aroma profile. While malt and hop aromas were prominent, they lacked the complex layers of floral and woody aromas found in Example 1. Although it possessed some taste harmony, the finish was short. The sensory score of Example 3 was also significantly lower than that of Example 1. Specifically, the taste was heavier, the bitterness was slightly abrupt, and although linalool was detectable in the aroma, the aroma complexity was insufficient due to the absence of nerolidol and humulene-II. Furthermore, the high amount of Chlorella added led to competition or inhibition with yeast metabolism, resulting in a less balanced overall flavor compared to Example 1. The product of Example 7, due to its pronounced algae-like odor and obvious sensory defects, was not included in the radar chart for visual comparison. Its specific sensory score data is shown in Table 2.

[0068] In summary, this invention has clarified the quality control mechanism of Chlorella proteinensis addition behavior in beer brewing through systematic research, and obtained the corresponding process parameters and methods. It has successfully solved the technical problems of weak functional activity and homogeneous flavor in traditional beer, and overcome the unpleasant flavor problem in the application of Chlorella. The beer produced has high antioxidant activity, rich and harmonious flavor and excellent physicochemical stability.

Claims

1. A brewing process for Chlorella proteinifera beer, characterized in that... Includes the following steps: 1) Soak the light-colored ale malt in water and then grind it, controlling the degree of grinding so that the ground malt is generally coarse powder with an intact husk rate of ≥80%; 2) The crushed malt is saccharified in stages at a material-to-water ratio of 1:3 at 45-78°C. The resulting mash is filtered and washed to obtain wort. 3) Boil the wort, and while it is boiling, add bitter hops, aroma hops, sea salt and coriander seeds in stages. After boiling, adjust the wort concentration to 11-13°P. 4) After cooling the wort, allow it to settle by vortexing. Transfer the clear wort from the top to a sterile fermentation vessel for aeration. After aeration, inoculate with activated brewer's yeast and simultaneously add sterilized Chlorella vulgaris powder. Initiate primary fermentation at 18–20°C. The primary fermentation is terminated when the apparent sugar content drops to 3.8–4.2°P and does not decrease further for two consecutive days. The amount of Chlorella vulgaris powder added is 1% of the malt mass. 5) After the primary fermentation is completed, glucose is added and bottled for secondary fermentation. After low-temperature storage and ripening, the finished product is obtained.

2. The brewing process for Chlorella proteoglycans beer according to claim 1, characterized in that: The heating saccharification process in step 2) is as follows: the crushed malt is added to water at a ratio of 1:3, the protein is first kept at 45°C for 30 minutes, and then the temperature is increased to 66°C at a rate of 1-1.5°C / min and kept at 66°C for at least 60 minutes for saccharification. After the iodine test is qualified, the temperature is increased to 78°C and kept at 78°C for 5 minutes to end the saccharification.

3. The brewing process for Chlorella proteoglycans beer according to claim 2, characterized in that: The filtration and washing process in 2) is as follows: the saccharified mash is pumped into the filter tank and filtered using the lees layer as the natural filter medium. The initial turbid wort is refluxed until it becomes clear, and the first wort is collected. Then, 78°C washing water is introduced in batches to wash the lees, with a total washing time not exceeding 90 minutes. The washing is stopped when the concentration of the residual washing liquid drops to 1.0-1.5°P. Collect and combine the first wort and the washed wort, and adjust the concentration of the combined wort to 11°P.

4. The brewing process for Chlorella proteoglycans according to claim 1, characterized in that: In step 3), the wort is boiled and kept boiling for 75 minutes; the bitter hops are added 10 minutes after boiling, the aromatic hops are added 60 minutes after boiling, and the sea salt and coriander seeds are added 65 minutes after boiling.

5. The brewing process for Chlorella proteoglycans beer according to claim 1, characterized in that: In step 4), the cooling treatment of the wort is as follows: the wort is cooled to 20°C using an ice-water bath; the settling and vortexing time is 30 minutes; the oxygenation treatment is as follows: sterile air is introduced into the wort until the dissolved oxygen content of the wort reaches 8-10 mg / L, and the oxygenation is completed within 10-15 minutes.

6. The brewing process for Chlorella proteoglycans according to claim 1, characterized in that: In step 5), the amount of glucose added is 4g / L. After bottling, it is stored at 18°C ​​in the dark for 10 days for secondary fermentation, and then refrigerated at 4°C for post-ripening.

7. The brewing process for Chlorella proteoglycans beer according to claim 1, characterized in that: In step 1), the proportion of coarse endosperm powder in the pulverized malt is 40% to 45%, and the proportion of fine powder is no more than 20%.

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