Preparation method of multifunctional humulus lupulus picric acid yeast microcapsule and application of multifunctional humulus lupulus picric acid yeast microcapsule in alcohol-free beer

Abstract

The invention relates to the technical field of beer brewing, in particular to a preparation method of a multifunctional hop picric acid yeast microcapsule and application of the microcapsule in alcohol-free beer. The yeast wall material is prepared by utilizing a plasm-wall separation method, the yeast wall material and the hop picric acid are jointly used for preparing the hop picric acid yeast microcapsule, and compared with a traditional method, the inclusion rate and the drug loading rate are greatly improved. In addition, the humulus lupulus picric acid yeast microcapsule is applied to beer, is stable in property, does not generate extra bitter taste, and can effectively improve the content of humulus lupulus picric acid in the beer. The humulus lupulus picric acid yeast microcapsule is applied to the alcohol-free beer, metabolism of the alcohol-free beer can be effectively promoted, and abdominal distension caused by the alcohol-free beer is prevented.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of beer brewing, in particular to a preparation method of multifunctional hop bitter acid yeast microcapsules and application thereof in non-alcoholic beer. BACKGROUND

[0002] Hop bitter acid is mainly derived from α-acid and β-acid and their derivatives in hops. Among them, α-acid is the most important bitter substance in hops, with a content of about 3%-14%, which has no bitterness itself, but isomerizes into iso-α-acid when wort is boiled, and iso-α-acid gives beer bitterness and has much better solubility than α-acid. α-acid is a mixture of five structural analogs, including humulone, cohumulone, adhumulone, posthumulone, and prehumulone, which differ in the alkyl group R of the side chain. The content of β-acid is generally 6%-8%, and the bitterness is weaker than that of α-acid, and it is difficult to dissolve in water, but it is easy to oxidize into soft resin with greater bitterness, and β-acid accounts for about 15% of beer bitter substances. β-acid is also a mixture of five structural analogs, including lupulone, co-lupulone, ad-lupulone, post-lupulone, and pre-lupulone. Soft resin in hop bitter acid belongs to the undefined part, including the oxidation products of α-acid and β-acid, and fresh hops contain 4%-6% of soft resin, which dissolves during wort boiling and has less bitterness, and becomes hard resin after oxidation. Hard resin, as the oxidation product of soft resin, δ-resin is produced by the oxidation of α-acid, and the bitterness is equivalent to 12%-22% of iso-α-acid, and ε-resin is produced by the oxidation of β-acid.

[0003] Hop bitter acid can give beer a unique bitterness, among which the bitterness of iso-α-acid is the most significant, and it has good solubility and can stably provide beer with the required bitterness, balance the sweetness of beer, and enhance the flavor level of beer. At the same time, it has the ability to prevent corrosion, α-acid has a certain ability to prevent corrosion, which can inhibit the growth of microorganisms in beer and prolong the shelf life of beer. And it can also improve the stability of beer foam, the polyphenol substances in hops interact with bitter acid, which helps to form stable beer foam and improve the taste and appearance of beer. At the same time, hop bitter acid and other ingredients such as hop oil in the beer brewing process can produce unique aroma and improve the flavor quality of beer.

[0004] A large amount of industrial by-product yeast is produced in the wine-making and food processing industries in China every year, and the treatment approach is relatively single and the added value is low. The beer waste yeast is the waste yeast discharged from the bottom of the fermentation tank after the beer fermentation is completed. At present, these waste yeasts are often made into dry yeasts or prepared into yeast extract after autolysis, and used for extracting nutrients such as proteins, nucleic acids and polysaccharides, or added to feed or fertilizer to increase nutrients. The above treatment methods have low utilization rate and low product added value, resulting in waste of beer waste yeast resources. The prior art has low efficiency and high cost in extracting functional components (such as beta-glucan and nucleic acid); in addition, the beer by-product yeast, due to the adsorption of hop resin, condensed solids and other substances in the fermentation process and the residue of the recovered beer, has problems such as poor color and bad smell. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a preparation method of multifunctional hop bitter acid yeast microcapsules and its application in alcohol-free beer.

[0006] The present application is realized by the following technical solutions: In a first aspect, the present application provides a preparation method of multifunctional hop bitter acid yeast microcapsules, comprising the following steps: Step one: washing of yeast mud Take beer waste yeast mud, then wash it with sterile deionized water, remove the supernatant, and obtain the washed yeast mud; Step two: preparation of yeast microcapsule wall material by plasmolysis method Disperse 60-120 parts of the yeast mud obtained in step one in 200-500 parts of NaOH solution, then stir at 60-80℃ for 1-4h to obtain a suspension, centrifuge the suspension, resuspend the obtained precipitate in 200-500 parts of hydrochloric acid (PH=4) after rinsing twice with sterile deionized water, then stir at 60-80℃ for 1-4h; then centrifuge, then rinse the yeast microcapsules collected by centrifugation with sterile deionized water for 2-3 times, then rinse with isopropyl alcohol for 4-6 times, acetone for 2-3 times, and low-temperature drying, to obtain hollow yeast microcapsules; Step three: preparation of hop bitter acid yeast microcapsules Add 5-20 parts of yeast microcapsules and 5-20 parts of hop bitter acid solution to 20-200 parts of sterile deionized water, shake for 1-4h, and spray dry to obtain hop bitter acid yeast microcapsules.

[0007] Preferably, the hop bitter acid in step three is iso-alpha acid, and the concentration is 30%.

[0008] Preferably, the low-temperature drying temperature in step two is 38-45℃.

[0009] In a second aspect, the present application provides application of the multifunctional hop bitter acid yeast microcapsule in non-alcoholic beer, and the addition amount of the multifunctional hop bitter acid yeast microcapsule in the non-alcoholic beer is 1.0-1.2 g / L.

[0010] Compared with the prior art, the present application has the following advantages: 1. The yeast wall material is prepared by the method of plasmolysis, and the hop bitter acid yeast microcapsule is prepared together with the hop bitter acid, so that the inclusion rate and the drug loading rate are greatly improved compared with the traditional method.

[0011] 2. The hop bitter acid yeast microcapsule is applied to non-alcoholic beer, has stable properties, does not produce additional bitterness, and can effectively improve the hop bitter acid content in non-alcoholic beer.

[0012] 3. The hop bitter acid yeast microcapsule is applied to non-alcoholic beer, can effectively promote the metabolism of non-alcoholic beer, and prevent abdominal distension caused by non-alcoholic beer. DETAILED DESCRIPTION

[0013] Example 1 1. Yeast mud cleaning: 100 parts of beer waste yeast mud are washed with sterile deionized water for 5 times, and the supernatant is removed to obtain the washed yeast mud.

[0014] 2. Preparation of yeast microcapsule wall material by plasmolysis method: 100 parts of the washed yeast mud are dispersed in 500 parts of 1 mol / L NaOH solution, and stirred at 80℃ for 2h. After centrifugation of the suspension, the obtained precipitate is rinsed with sterile deionized water for 2 times and resuspended in 500 parts of hydrochloric acid (pH=4), and stirred at 80℃ for 1h. The yeast microcapsule collected by centrifugation at 5000rpm for 5min is washed with sterile deionized water for 2 times. Then it is rinsed with isopropyl alcohol for 4 times, acetone for 2 times, and dried at 40℃ to obtain the hollow yeast microcapsule wall material.

[0015] 3. Preparation of hop bitter acid yeast microcapsule: 10 parts of yeast microcapsule wall material and 10 parts of iso-alpha-acid solution (30%) are added into 100 parts of sterile deionized water, and shaken for 2h. Then, spray drying is performed to obtain the iso-alpha-acid yeast microcapsule.

[0016] Example 2 1. Yeast mud cleaning: 80 parts of beer waste yeast mud are washed with sterile deionized water for 4 times, and the supernatant is removed to obtain the washed yeast mud.

[0017] 2. Preparation of yeast microcapsule wall material by plasmolysis method: 80 parts of washed yeast paste was dispersed in 300 parts of 1 mol / L sodium oxide solution, and stirred at 70°C for 1 h. After centrifugation of the suspension, the obtained precipitate was rinsed with sterile deionized water for 3 times and then resuspended in 300 parts of hydrochloric acid (pH = 4) and stirred at 70°C for 1 h. The yeast microcapsules collected by centrifugation at 4500 rpm for 4 min were rinsed with sterile deionized water for 3 times. Then, the yeast microcapsules were rinsed with isopropyl alcohol for 3 times, with acetone for 3 times, and dried at low temperature of 42°C to obtain the hollow yeast microcapsule wall material.

[0018] 3. Preparation of hop bitter acid yeast microcapsules: 18 parts of yeast microcapsule wall material and 10 parts of α-acid solution (20%) were added into 100 parts of sterile deionized water, respectively, and shaken for 2 h, and then spray dried to obtain α-acid yeast microcapsules.

[0019] Comparative Example 1 1. Washing of yeast paste: 100 parts of beer waste yeast paste was washed with sterile deionized water for 5 times, and the supernatant was removed. The yeast paste was dried at low temperature of 40°C to obtain the washed yeast dry powder.

[0020] 2. Preparation of hop bitter acid yeast microcapsules: 10 parts of washed yeast dry powder and 10 parts of iso-α-acid solution (30%) were added into 100 parts of sterile deionized water, respectively, and shaken for 2 h, and then spray dried to obtain iso-α-acid yeast microcapsules.

[0021] Experimental Example 1. Inclusion rate and drug loading rate analysis The detection results of various indexes of the hop bitter acid yeast microcapsules prepared in the above examples and comparative examples. Inclusion rate determination: 0.1 g of hop bitter acid yeast microcapsules was rinsed with alcohol for 3 times, and then mixed with 10 ml of ethanol. The mixture was ultrasonicated at 20°C for 30 min, and then shaken on a shaking table at 180 rpm for 6 h. The supernatant was collected by centrifugation at 6000 rpm for 10 min, and the content of hop bitter acid was determined. The inclusion rate was calculated according to the following formula: Inclusion rate (%) = mass of hop bitter acid in hop bitter acid yeast microcapsules / mass of hop bitter acid before inclusion x 100%.

[0022] Drug loading rate (%) = mass of hop bitter acid in hop bitter acid yeast microcapsules / mass of total hop bitter acid yeast microcapsules.

[0023] Table 1. Inclusion rate and drug loading rate of hop bitter acid yeast microcapsules The results show that, compared with Comparative Example 1, Examples 1 and 2 effectively improve the inclusion rate and drug loading rate of hop bitter acid yeast microcapsules.

[0024] Experimental Example 2 The hop bitter acid yeast microcapsules containing 50, 100, 200, 300 mg of iso-alpha-acids and the same amount of iso-alpha-acids in the form of hop bitter acid were added to 1 L of wheat beer, respectively. Eight experienced tasters were invited to conduct sensory evaluation according to the ASBC analysis method. The results are shown in Table 2.

[0025] Table 2 Evaluation results of hop bitter acid yeast microcapsules It is shown that iso-alpha-acids with the above concentrations have obvious or strong bitterness, while hop bitter acid yeast microcapsules containing the same amount of iso-alpha-acids have no obvious bitterness.

[0026] Experimental Example 3. Analysis of abdominal distension in non-alcoholic beer 1 g of hop bitter acid yeast microcapsules prepared in Example 1 was added to 1 L of non-alcoholic beer. Two groups of volunteers, each consisting of 10 people, were invited: the experimental group drank 1 L of non-alcoholic beer added with hop bitter acid yeast microcapsules within 1 h, and the control group drank 1 L of non-alcoholic beer within 1 h. The volunteers were not informed of the type of beverage they drank. Then, according to Table 3, the volunteers scored according to their feelings after drinking. The higher the score, the stronger the abdominal distension. The results are shown in Table 4.

[0027] Table 3 Abdominal distension scale Table 4 Scores of volunteers Packet Average score Experimental group 1.6±0.17 Control group 4.8±0.26 The results show that non-alcoholic beer is prone to cause abdominal distension, and non-alcoholic beer added with hop bitter acid yeast microcapsules effectively reduces the abdominal distension caused by non-alcoholic beer.

Claims

1. A method for preparing multifunctional hop bitter yeast microcapsules, characterized in that, Includes the following steps: Step 1: Washing the yeast sludge Take the waste yeast sludge from beer, then wash it with sterile deionized water, and after removing the supernatant, you will get the washed yeast sludge. Step 2: Preparation of yeast microcapsule wall material by plasmolysis Disperse 60-120 parts of the yeast slurry obtained in step one into 200-500 parts of NaOH solution, and then stir at 60-80℃ for 1-4 hours to obtain a suspension. After centrifuging the suspension, wash the resulting precipitate twice with sterile deionized water and resuspend it in 200-500 parts of hydrochloric acid (pH=4), and then stir at 60-80℃ for 1-4 hours. Then centrifuge the precipitate and wash the collected yeast microcapsules 2-3 times with sterile deionized water, then wash 4-6 times with isopropanol and 2-3 times with acetone, and then dry at low temperature to obtain hollow yeast microcapsules. Step 3: Preparation of hop bitter yeast microcapsules Add 5-20 parts of yeast microcapsules and 5-20 parts of hop bitter acid solution to 20-200 parts of sterile deionized water, shake for 1-4 hours, and spray dry to obtain hop bitter acid yeast microcapsules.

2. The method according to claim 1, characterized in that, In step three, the bitter acid from hops is an iso-α-acid with a concentration of 30%.

3. The method according to claim 1, characterized in that, In step two, the low-temperature drying temperature is 38-45℃.

4. The application of a multifunctional hop bitter yeast microcapsule prepared using any one of claims 1-3 in non-alcoholic beer, characterized in that, The addition amount of multifunctional hop bitter acid yeast microcapsules to beer is 1.0-1.2g / L.

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