CN112280628A

CN112280628A - Method for producing litchi flower beer

Info

Publication number: CN112280628A
Application number: CN201910659440.0A
Authority: CN
Inventors: 刘世诠; 沈祐成; 黄乔琪
Original assignee: Chung Shan Medical University
Current assignee: Chung Shan Medical University
Priority date: 2019-07-22
Filing date: 2019-07-22
Publication date: 2021-01-29

Abstract

The invention relates to a method for preparing litchi flower beer, which comprises the following steps: boiling a saccharified grain juice with the sugar degree of 10-15 Brix, adding a dried litchi flower material when the saccharified grain juice is boiled, and continuously boiling for 30-90 minutes to obtain litchi flower saccharified grain juice; cooling the lychee flower saccharified grain juice, adding a yeast to perform a first fermentation step, and obtaining a first fermentation product; adding a sugar material into the first fermentation product, and performing a second fermentation step to obtain the litchi flower beer.

Description

Method for producing litchi flower beer

Technical Field

The invention relates to a method for manufacturing litchi flower beer, in particular to beer brewed by taking litchi flower as a raw material.

Background

The beer is an alcoholic beverage prepared by hydrolyzing and fermenting starch and generating sugar, the starch is mainly from barley malt, and hops are added in the fermentation process, so that the beer has unique bitterness and fragrance, and the effects of antibiosis and corrosion prevention are achieved; in addition, other raw materials can be added in the beer process to manufacture more kinds of beer, such as the production method of the tartary buckwheat beer disclosed in CN103275838A, wherein tartary buckwheat and rice are added into malt, and Rutin (Rutin) is added to prepare the tartary buckwheat beer with fine foam and containing beneficial components; also, CN102978053A discloses a preparation method of scented tea beer, which is to ferment the hops and the scented tea powder together, so that the prepared scented tea beer has good taste and improves the economic value of the beer.

Litchi is a common fruit in Taiwan, the flavor of the fruit is unique and is widely favored, and recent research finds that litchi flowers are rich in rich antioxidant substances, but the litchi flowers are not properly utilized at present.

Disclosure of Invention

The method for producing litchi flower beer of the present invention comprises: boiling saccharified grain juice with the sugar degree of 10-15 Brix; secondly, adding dried litchi flower materials in the boiling process of the saccharified grain juice, and continuously boiling for 30-90 minutes to obtain litchi flower saccharified grain juice; step three, cooling the lychee flower saccharified grain juice, adding yeast to perform a first fermentation step, and obtaining a first fermentation product; and step four: adding sugar material into the first fermentation material and performing a second fermentation step to obtain litchi flower beer.

In one embodiment, the pure water is heated to 70-80 ℃ and put into the grain material, and the temperature of the pure water is maintained at 60-70 ℃ for 1-3 hours to obtain the saccharified grain juice.

In one embodiment, the cereal material is one of malt and rice, and must include malt.

In one embodiment, the dried litchi flower material is litchi flower dried at 0-100 ℃.

In one embodiment, the dried litchi flower material is litchi flower dried at 0 deg.C, 50 deg.C, 75 deg.C or 100 deg.C.

In one embodiment, the dried litchi flower material is added after the saccharified grain juice is boiled for 0-50 minutes, and the total boiling time of the saccharified grain juice is 60 minutes.

In one embodiment, the first fermentation step is carried out at 20-25 ℃ for 5-10 days.

In one embodiment, the second fermentation step is performed at 0-10 ℃ for 10-20 days.

In one embodiment, the yeast is Saccharomyces cerevisiae.

In one embodiment, the sugar material is sucrose.

Therefore, the invention takes the litchi flowers as the material, and the beer is brewed by matching the litchi flowers with the barley malt or the saccharified grain juice made from the mixed grains containing the barley malt and the rice, and the prepared beer has pleasant taste, is rich in polyphenol and total flavonoids, and has excellent economic value and nutritive value.

Drawings

FIG. 1 is a flow chart of the method for producing litchi flower beer of the present invention.

FIG. 2A is an analysis chart of the influence of litchi flower drying temperature on total soluble solids of beer.

FIG. 2B is a graph illustrating the influence of litchi flower drying temperature on beer alcoholic strength.

FIG. 3A is a graph of pH analysis of beer affected by litchi flower drying temperature.

FIG. 3B is a graph showing the effect of litchi flower drying temperature on the total acid content of beer.

FIG. 4A is an analysis chart of L value of beer affected by litchi flower drying temperature.

FIG. 4B is an analysis chart of influence of litchi flower drying temperature on beer a value.

FIG. 5 is an analysis chart of influence of litchi flower drying temperature on beer b value.

FIG. 6A is a graph of the effect of litchi flower boiling time on total soluble solids in beer.

FIG. 6B is a graph showing the influence of litchi flower boiling time on beer alcoholic strength.

FIG. 7A is a graph of pH analysis of beer as a function of time of litchi flower boiling.

FIG. 7B is a graph of analysis of the influence of litchi flower boiling time on total acid content of beer.

FIG. 8A is a graph showing the effect of litchi flower boiling time on L value of beer.

FIG. 8B is a graph showing the effect of litchi flower boiling time on beer a value analysis.

FIG. 9 is a graph showing the effect of litchi flower boiling time on beer b value analysis.

FIG. 10A is a graph showing the effect of litchi flower addition ratio on total soluble solids in beer.

FIG. 10B is a graph showing the influence of the addition ratio of litchi flowers on the alcoholic strength of beer.

FIG. 11A is a graph of pH analysis of beer as a function of litchi flower addition ratio.

FIG. 11B is an analysis chart of the influence of litchi flower addition ratio on total acid content of beer.

FIG. 12A is a graph showing the effect of the ratio of rice added on the total soluble solids in beer.

FIG. 12B is a graph showing the influence of the addition ratio of rice on the alcoholic strength of beer.

FIG. 13A is a graph of analysis of influence of rice addition ratio on pH of beer.

FIG. 13B is a graph showing the effect of the ratio of rice added on the total acid content of beer.

Detailed Description

The purpose and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments, which is to be read in connection with the accompanying drawings. Further, the scope of practical application of the present invention will be further demonstrated by the following specific examples, which are not intended to limit the scope of the invention in any way.

Referring to fig. 1, the present invention provides a method for producing a lychee flower beer, comprising: boiling saccharified grain juice with the sugar degree of 10-15 Brix; secondly, adding dried litchi flower materials in the boiling process of the saccharified grain juice, and continuing to boil for 30-90 minutes to obtain litchi flower saccharified grain juice; step three, cooling the lychee flower saccharified grain juice, and adding yeast to perform a first fermentation step to obtain a first fermentation product; and step four: adding sugar material into the first fermentation material and performing a second fermentation step to obtain litchi flower beer.

EXAMPLE I method for producing litchi flower beer

Preparation of lychee flower saccharified cereal juice

The grain material for preparing saccharified grain juice is American Elegano malt or grain material mixed with American Elegano malt and Taiwan polished round-grained rice in different proportions; american ale barley malt is available from brewers park and taiwan army rice, taidong royal cereal burger (guanshan cereal burger ltd), but is not intended to limit the scope of the invention in this regard. The preparation process comprises the following steps:

heating 5 liters of pure water to 70-80 ℃, in this embodiment, to 74 ℃; 1 kg of grain material is put into a filter screen and heated in pure water, and the temperature of the pure water is controlled to be 60-70 ℃, such as 64-68 ℃ in the embodiment, so as to achieve a better saccharification effect; heating for 1-3 hours, preferably 2-2.5 hours, monitoring the sugar degree of the grain juice every 30 minutes, and taking out a filter screen filled with grain materials after the sugar degree of the grain juice reaches 10-15 DEG Brix to obtain saccharified grain juice; the saccharified cereal juice used subsequently has a Brix of 12 °.

Boiling the saccharified grain juice with the sugar degree of 12 DEG Brix with strong fire, adding 0.1-0.5 wt% of dried litchi flower material, turning the strong fire to be small, maintaining the micro-rolling state of the saccharified grain juice with small fire, continuously boiling for 1-1.5 hours, and filtering to obtain the litchi flower saccharified grain juice. The dried litchi flower material is dried black-leaf litchi flower, which is harvested after the litchi tree blooms, and then is subjected to freeze drying and drying treatment at 50 ℃, 75 ℃ or 100 ℃ to obtain the dried litchi flower material.

(II) fermentation step

Cooling the lychee flower saccharified grain juice to room temperature, adding 3g of yeast into 3.5L of the lychee flower saccharified grain juice, uniformly mixing, bottling, and performing a first fermentation step at 20-25 ℃ for 5-10 days to obtain a first fermentation product, wherein the yeast is selected from Datstar Munich yeast (Saccharomyces cerevisiae) of Saccharomyces cerevisiae; in this example, the fermentation time of the first fermentation step was 6 days, and the product was monitored for changes in the basic composition and properties every 3 days. Filtering the first fermentation product, adding sucrose which accounts for 5 wt% of the weight of the filtrate into the filtrate, uniformly mixing, subpackaging the mixture into a light-proof wine bottle, and performing a second fermentation step at 0-10 ℃ for 10-20 days to obtain litchi flower beer; in this example, fermentation was carried out at 7 ℃ for 15 days, and the change in the basic composition of the product was monitored every 3 days.

The results of the analysis in the following table are the "mean" + -standard deviation (standard deviation) "of three replicates and were analyzed by the Duncan-test statistical method; if the letters indicated on the upper right of the two test results are different, it indicates that the measurement results between the two groups have significant difference (p < 0.05).

Example II characterisation of litchi flower beer

(I) influence of litchi flowers with different drying temperatures on litchi flower beer

Adding lyophilized litchi flower, dried litchi flower at 50 deg.C, 75 deg.C or 100 deg.C into saccharified grain juice prepared from pure barley malt, and detecting the characteristics of the obtained litchi flower beer; the hop control group is beer prepared from dried hops, but the other preparation processes are the same as the preparation method of litchi flower beer. In addition, the following fermentation times are represented by "one-0" for "0 day after the first fermentation step", "one-3" for "3 days after the first fermentation step", "two-0" for "0 day after the second fermentation step", "two-3" for "3 days after the second fermentation step", and so on. Wherein the second fermentation step time is 15 days, indicated as "two-15", and the beers of each group are considered as having been fermented and having been matured completely at the time point of two-15.

Referring to fig. 2A and table 1, the total soluble solids (total soluble solids) content of each group is between 13 ° Brix and 15 ° Brix at a time of one-0, and the total soluble solids content of each group is reduced to 6 ° Brix to 7 ° Brix at a time of one-3; the total soluble solids content of each group was slightly increased after sucrose addition (two-0).

TABLE 1

Referring to fig. 2B, when the alcoholic strength of each group rises to 4.5-5% in the first-3, the alcoholic strength of the 75 ℃ dried litchi flower group and the alcoholic strength of the 100 ℃ dried litchi flower group reach a balance, and no continuous rise is caused in the subsequent steps; after the litchi chinensis flowers are ripened (II-15), the highest alcoholic strength of the litchi chinensis flowers after being dried at 50 ℃ is 6.00 percent, and the secondary alcoholic strength of the litchi chinensis flowers after being dried is 5.73 percent and is higher than that of the hop control group.

Referring to Table 2, in cases one-3, the total carbohydrate content of each group rapidly decreased until the end of the second fermentation step (two-15); after the ripening is completed, the total saccharide content of each sample is the highest in the freeze-dried litchi flower group. According to fig. 2B and table 2, the consumption rate of the total saccharide content and the alcohol production rate (alcohol content) of each group have the same trend, and are 50 ℃ dried litchi flower group > freeze-dried litchi flower group > hop control group.

TABLE 2

Please see table 3, the reducing saccharide content of each group shows a stable decreasing trend, wherein the average reducing saccharide content of the hop control group, the freeze-dried litchi flower group and the dried litchi flower group at 100 ℃ (two-15) after ripening is 7-8 mg/mL; the content of reducing saccharide in the litchi flower group dried at 50 ℃ is higher at the beginning and after the end of fermentation; the content of reducing saccharide in the litchi flower group dried at 75 ℃ is lower at the beginning and after the end of fermentation; overall, the trend of the reducing saccharide content is similar to the trend of the total soluble solids.

TABLE 3

Referring to fig. 3A, the pH of the five groups of samples averaged at pH-0 to 5 and tended to decrease with increasing fermentation time, and at pH-15 to 3.85.

The acidic substances in the wine are mainly derived from metabolism of raw materials and microorganisms, and the generated organic acids comprise lactic acid, malic acid and succinic acid by taking yeast fermentation as an example, and the composition and the content of the organic acids have great influence on the flavor of the wine; referring to fig. 3B, when one to 3 of the five samples are obtained, the total acid content is 0.3 to 0.35%, and the total acid content increases as the fermentation time increases; wherein the total acid content of the litchi flower group dried at the temperature of 75 ℃ and the litchi flower group dried at the temperature of 100 ℃ is less in change. In addition, the volatile acid in the wine can be used as an index for judging whether the wine is polluted by infectious microbes or not in the fermentation process, the types of the volatile acid comprise formic acid, acetic acid, butyric acid and the like, and if the volatile acid in the wine exceeds 0.12 percent, the wine is polluted by acetic acid bacteria or lactic acid bacteria; in addition, different fermentation strains, fermentation temperatures and raw material types also influence the generation of acetic acid; after aging (two-15), the volatile acid content of each group was within the specified range (0.12%).

Then measuring the appearance of the beer by using a color difference meter, wherein the L value is the lightness of the sample, the a value is the red chroma of the liquor, and the b value is the yellow chroma of the liquor; + a for the color towards red, -a for the color towards green, -b for the color towards yellow, -b for the color towards blue. Referring to FIG. 4A, at time one-3, the wine had already settled and the brightness (L value) increased significantly; in general, the L values of the freeze-dried litchi flower group, the 50 ℃ and 100 ℃ dried litchi flower group and the hop control group are increased from 60 to 80 on average, and the L value of the 75 ℃ dried litchi flower group is increased from 40 to 70; referring to fig. 4B, as the fermentation time increased, the average of the values of a values of the four groups decreased from 12 to 5, except that the value of a of the freeze-dried litchi flower group decreased from 8.17 to 5.16.

Referring to fig. 5 again, as the fermentation time increases, the b value of the litchi flower group dried at 50 ℃ increases from 58.69 to 75.22, and then decreases and is stably maintained at 61.31; the b value of the litchi flower group dried at the temperature of 75 ℃ is reduced from 43.85 to 35.02, and then is increased to 52.75; the b values of the remaining groups were maintained around 55 without much change. The color of the litchi flower beer in this example was brown when observed with naked eyes.

See table 4 for analysis of total phenol, total flavone content and total antioxidant capacity for each group; the total phenol content is expressed as Gallic Acid Equivalent (GAE), and the total flavone content is expressed as Catechin Equivalent (CE); the total phenol content of the litchi flower group dried at 50 ℃ is the highest in each group, but the total phenol content of each group is less than 0.5mg GAE/g wine. In the four groups of litchi flower beers, the total flavone content of the freeze-dried litchi flower group is the highest in the litchi flower beer group and is similar to that of the litchi flower group dried at 50 ℃, and the total flavone content of the litchi flower group dried at 100 ℃ is also similar to that of the litchi flower group dried at 50 ℃.

Total antioxidant capacity was analyzed for ABTS of the above groups of samples⁺³Minimum scavenging concentration of free radicals (EC)₅₀) Thus EC₅₀Lower indicates higher antioxidant capacity of the sample; wherein EC of litchi flower group is dried at 50 DEG C₅₀The minimum is 0.085 +/-0.001 mg/mL, and the EC of the litchi flower group is dried at 100 DEG C₅₀Similar to the litchi flower group dried at 50 ℃; the freeze-dried litchi flower group and the litchi flower group dried at 75 ℃ belong to two groups with weak oxidation resistance.

TABLE 4

	Total phenols (mg GAE/g wine)	Total flavonoids (mg CE/g wine)	ABTS⁺³EC₅₀(mg/mL)
				Control group of hop	0.44±0.01^ab	0.071±0.002^a	0.081±0.000^b
Freeze-dried litchi flower	0.41±0.00^cd	0.061±0.003^b	0.096±0.005^a
				Drying litchi flower at 50 DEG C	0.47±0.01^a	0.059±0.004^b	0.085±0.001^b
Litchi flower dried at 75 DEG C	0.42±0.00^bc	0.048±0.007^c	0.097±0.001^a
				Litchi flower dried at 100 DEG C	0.40±0.02^d	0.057±0.000^b	0.086±0.002^b

Further performing a functional evaluation, analyzing the sparkling feeling (sparkle), color (color), aroma (aroma), taste (taste) and overall preference (overall) of the aged litchi flower beer, randomly collecting 30 evaluation persons, and scoring by 9 scores, wherein 1 score is extremely unpleasant, 3 score is unpleasant, 5 score is disliked or not unpleasant, 7 score is favorite, and 9 score is extremely favorite; the same criteria were used for the functional evaluations of the subsequent examples.

Please see table 5, the color of the 75 ℃ dried litchi flower group is relatively turbid when observed by naked eyes, so the overall evaluation is relatively low, and the color performance of other three groups of litchi flower beer and the hop control group has no obvious difference; the fragrance evaluation results of the hop control group, the freeze-dried litchi flower group and the 50 ℃ dried litchi flower group are not obviously different, the fragrance of the 75 ℃ dried litchi flower group is not obvious, and the evaluation personnel show that the hop control group, the freeze-dried litchi flower group and the 50 ℃ dried litchi flower group smell sweeter, while the 75 ℃ dried litchi flower group and the 100 ℃ dried litchi flower group smell light fragrance; the assessment of the bubbling sense of the hop control group, the freeze-dried litchi flower group and the 50 ℃ dried litchi flower group has no obvious difference, and the hop control group, the freeze-dried litchi flower group and the 50 ℃ dried litchi flower group have slight bubbling sense, but the 75 ℃ dried litchi flower group and the 100 ℃ dried litchi flower group have almost no bubbling sense; the taste and overall preference evaluation of the hop control group, the freeze-dried litchi flower group and the 50 ℃ dried litchi flower group are not obviously different, but according to the opinion of a appraiser, the 75 ℃ dried litchi flower group beer has light taste and is sour to drink, so that the overall preference is influenced. According to the above suggestions, compared with the hop control group, the freeze-dried litchi flower group and the litchi flower group dried at 50 ℃ have less obvious bitter taste and are fragrant and sweet in smell.

TABLE 5

	Color	Fragrance	Feeling of bubbles	Taste of the product	Overall preferences
						Control group of hop	6.20±1.93^AB	6.00±1.41^AB	6.20±2.15^A	7.00±2.83^A	6.40±2.50^A
Freeze-dried litchi flower	6.00±2.54^AB	7.20±1.99^A	6.40±2.32^A	6.80±0.63^A	6.60±1.58^A
						Drying litchi flower at 50 DEG C	6.60±1.58^A	5.20±2.20^AB	5.80±2.15^AB	5.60±2.67^AB	6.00±2.71^A
Litchi flower dried at 75 DEG C	2.60±2.07^C	2.60±2.64^C	2.80±2.20^C	2.60±2.07^C	2.20±1.69^B
						Litchi flower dried at 100 DEG C	4.40±2.32^BC	4.80±2.90^B	4.00±2.71^BC	4.00±2.36^BC	4.40±2.84^A

By combining the analysis, the freeze-dried litchi flower beer and the 50 ℃ dried litchi flower beer have better performances, and the litchi flower beer is prepared by taking 50 ℃ dried litchi flowers as materials in the following process in consideration of the manufacturing convenience and cost.

(II) influence of litchi flower boiling time on litchi flower beer

In the second testing step, the preparation conditions that 50 ℃ is added for drying litchi flowers at different times after the saccharified cereal branches are boiled and are changed into the small-fire micro-rolling state, and the total time for continuously boiling the saccharified cereal branches to the small-fire micro-rolling state is 1 hour are tested, so that the influence on the litchi flower beer is avoided; the cooking time of the example in which 0 minute was added was 60 minutes, and subsequently referred to as "60 minute group", the cooking time of the example in which 10 minutes was added was 50 minutes and thus referred to as "50 minute group", the cooking time of the example in which 20 minutes was added was 40 minutes and thus referred to as "40 minute group", and the cooking time of the example in which 30 minutes was added was 30 minutes and thus referred to as "30 minute group". The boiled lychee flower saccharified wort is continuously subjected to the first fermentation step and the second fermentation step, and the product properties of each fermentation stage are measured.

Referring to fig. 6A and table 6, the longer the boiling time, the higher the total soluble solids content in the saccharified wort, and the better the alcohol production rate in the 60-minute group is estimated from the change in total soluble solids.

TABLE 6

Referring again to FIG. 6B, the alcohol concentrations for the groups at-3 averaged 3% with the exception that the alcohol concentration for the 40 minute group at-3 was 2%; after the ripeness (II-15), the alcoholic strength of each group is respectively as follows: 4.4% in 30-minute group, 2.77% in 40-minute group, 3.2% in 50-minute group and 4.3% in 60-minute group; if the alcohol production speed is calculated, the speed is from fast to slow: 30-minute group > 60-minute group > 40-minute group > 50-minute group.

Please refer to table 7, the trend of the total saccharide content of each group is not positively correlated to the trend of the total soluble solid content; if the consumption rate of the total saccharide content is calculated, from fast to slow: 30-minute group > 60-minute group > 40-minute group > 50-minute group, the trend was the same as the alcohol production rate. Also, according to table 8, the trend of the content of reducing saccharides of each group was the same as the trend of the total soluble solid content.

TABLE 7

TABLE 8

Referring to fig. 7A, the initial pH of the 60-minute group was 4.96, the pH after maturation was 4.06, and the variation was minimal; the initial pH value of the 50 minute group was pH 4.46, after maturation pH 3.52; the initial pH of the 40 minute group was pH 5.22, after maturation pH 3.38; the initial pH of the 30 min batch was 4.21 and after maturation was 3.46. Referring to fig. 7B, at times one-3, the total acid content of each group increased significantly, but the total acid content of the subsequent 60 minute group did not change much, and the total acid content of the other groups still increased with the increase of the fermentation time; the total acid content of the 60-minute group increased from 0.08% to 0.29%, the 50-minute group increased from 0.13% to 0.37%, the 40-minute group increased from 0.14% to 0.38%, and the 30-minute group increased from 0.09% to 0.43%; after the maturation, there are groups with a decrease in the total acid content, probably due to the esterification of part of the organic acids.

The initial average content of volatile acid in each group was 0.008%, and the volatile acid content in each group after aging was as follows: 0.041% for 30-minute group, 0.041% for 40-minute group, 0.033% for 50-minute group, and 0.029% for 60-minute group, all meeting the relevant specifications.

Referring to fig. 8A, the initial L values for the four groups averaged 80, and the clarity and brightness increased to about 90 after precipitation. Referring again to FIG. 8B, the a value for the 30-minute group decreased from 0.59 (one-0) to-0.60 (two-15), the a value for the 40-minute group decreased from 1.8 (one-0) to-1.16 (two-15), the a value for the 50-minute group decreased from 0.24 (one-0) to-0.15 (two-15), and the a value for the 60-minute group decreased from 1.31 (one-0) to-0.52 (two-15).

Referring to FIG. 9, the b value for the 30 minute group decreased from 33.78 (one-0) to 27.69 (one-6) and then increased to 29.54 (two-15); the b value of the 40-minute group is reduced from 33.47 (one-0) to 23.24 (two-15); the b value of the 50-minute group rises from 25.77 (one-0) to 28.40 (one-3) and then falls to 21.52 (two-15); and the b value of the 60-minute group is slightly reduced from 22.14 (one-0) to 21.16 (two-15); the b values of the products after the ripening of each group are positive values, so the colors of the wine liquids of the four groups are yellow, and the prepared litchi flower beer is brown by combining the analysis of the L value and the a value.

Referring to Table 9, the total phenol content of each of the four groups was less than 0.3mg GAE/g wine, the total phenol and total flavone content of the 30-minute group was the highest in the four groups, the total phenol content of the 50-minute group was the lowest in the four groups, and the total flavone content of the 60-minute group was the lowest in the four groups, but 0.090. + -. 0.00mg CE/g extract was still present; however, the total antioxidant capacity analysis results showed that the antioxidant capacity of the 60-minute group was the best, with its EC₅₀Is 0.110 plus or minus 0.006 mg/mL; combining the above results, the total antioxidant capacity of the obtained product is the best of four groups for the group of litchi flower boiling for 60 minutes.

TABLE 9

	Total phenols (mg GAE/g liquor))	Total flavonoid (mg CE/g liquor)	ABTS⁺³EC₅₀(mg/mL)
				30 minutes	0.26±0.01^a	0.116±0.00^d	0.120±0.002^c
40 minutes	0.25±0.02^ab	0.097±0.00^b	0.129±0.001^b
				50 minutes	0.22±0.01^c	0.107±0.00^c	0.148±0.000^a
60 minutes	0.24±0.01^bc	0.090±0.00^a	0.110±0.006^d

Referring to table 10, there was no significant difference in the color assessment for each group; on the evaluation of the aroma, the score is 60 minutes to 50 minutes to 30 minutes to 40 minutes from high to low, and the 60 minutes and the 50 minutes have sweeter odor; also, the four groups had low bubbling; the taste and overall preference did not differ significantly between the 60, 50 and 30 minute groups, but the 40 minute group had a poor assessment; the panelists indicated that the 60-and 50-minute groups of litchi flower beer were slightly bitter tasting similar to the prior art beer, while the 30-minute group of litchi flower beer smelled more fragrant and tasted less bitter.

Watch 10

In conclusion, the litchi flower beer prepared after the litchi flower is boiled for 60 minutes has better average characteristics, so in the subsequent preparation embodiment, the litchi flower is boiled in the saccharified grain juice for 60 minutes.

(III) influence of litchi flower addition amount on litchi flower beer

In this example, 0.20 wt% to 0.40 wt% of litchi flower was added to saccharified wort and dried at 50 ℃ and boiled in the saccharified wort for 60 minutes, and then the characteristics of the beer were observed.

Referring to fig. 10A, the initial total soluble solids content of the 0.20 wt% litchi floral group was 12.0 ° Brix, and 8.0 ° Brix after ripening; the initial total soluble solids content of the 0.30 wt% litchi floret was 12.0 ° Brix, 8.0 ° Brix after ripening; the initial total soluble solids of the 0.40 wt% litchi flower group was 12.2 ° Brix and 7.2 ° Brix after ripening, indicating that the alcohol production rate was better with the addition of 0.40 wt% litchi flower.

Referring to FIG. 10B, the alcohol content of 0.20 wt% litchi flower group increased to 3.57% at a time of-3 and increased with the increase of fermentation time, and the alcohol content began to decrease at a time of-6 and became 3.7% after aging; the alcoholic strength of 0.30 wt% litchi flower group is increased to 3.0% when the alcoholic strength is one-3%, the subsequent alcoholic strength is not obviously changed, and the alcoholic strength after ripening is 3.1%; the alcoholic strength of 0.40 wt% litchi flower group is increased to 3.83% at a time of-3, and is increased with the increase of fermentation time, and the alcoholic strength is increased to 4.6% at a time of-6, and then the alcoholic strength is stably maintained to 4.5% after aging; the alcoholic strength of the litchi flower group with the alcoholic strength of 0.40 wt% and more than 0.20 wt% and more than 0.30 wt% is the same as the analysis result of the total soluble solid content.

Table 11 shows the analysis results of total sugar content, and according to the decreasing trend of total sugar content, the alcohol production rate is calculated from fast to slow, which is 0.40 wt% litchi flower group >0.20 wt% litchi flower group >0.30 wt% litchi flower group, and the change trend is the same as the change trend of the total soluble solid content and the alcohol content analysis results. Table 12 shows the analysis results of reducing saccharide content, from high to low, the variation trend is the same as the analysis results of the total soluble solid content, alcohol content and total saccharide content, for 0.40 wt% litchi flower group >0.20 wt% litchi flower group >0.30 wt% litchi flower group.

TABLE 11

TABLE 12

Referring to fig. 11A, the pH of the 0.20 wt% litchi floral grouping was lowered from pH 4.62 to pH 3.62, the 0.3 wt% litchi floral grouping was lowered from pH 5.21 to pH 3.38, and the 0.40 wt% litchi floral grouping was lowered from pH 5.49 to pH 3.63. Referring to fig. 11B again, the total acid content of 0.20 wt% litchi flower group and 0.40 wt% litchi flower group after ripening (two-15) is 0.47% and 0.44%, respectively, which are not different from each other, while the total acid content of 0.3 wt% litchi flower group after ripening is 0.58%, which is significantly higher than that of the other two groups; in addition, the contents of the volatile acids in the three groups all meet the relevant specifications.

Referring to table 13, the total phenol content of 0.40 wt% of the litchi flower group was the highest among the three groups; the total flavone content of the 0.40 wt% litchi flower group is similar to that of the 0.30 wt% litchi flower group, and the total flavone content is higher than that of the 0.20 wt% litchi flower group; furthermore, 0.40 wt% of litchi flower group has the best oxidation resistance

Watch 13

Table 14 shows the results of the analysis of the functional evaluation; the color evaluation results of the three groups have no obvious difference, the fragrance evaluation score is 0.4 wt% of litchi flower group >0.2 wt% of litchi flower group >0.3 wt% of litchi flower group from high to low, and the appraiser indicates that 0.4 wt% of litchi flower group smells sweet and has strong fragrance; the 0.2 wt% litchi flower group and the 0.3 wt% litchi flower group have no bubble feeling completely, and the 0.4 wt% litchi flower group has a slight bubble feeling; the taste and overall preference score of the 0.4 wt% litchi flower group was high, and the panelists showed that the 0.4 wt% litchi flower group had a slightly bitter and astringent taste similar to that of the commercially available beer, while the 0.2 wt% litchi flower group had less bitterness and astringency.

TABLE 14

	0.20 wt% of litchi flower	0.30 wt% of litchi flower	0.40 wt% of litchi flower
				Color	5.20±2.06^A	5.73±1.93^A	5.77±1.96^A
Fragrance	5.47±2.27^B	4.47±1.66^C	6.40±1.90^A
				Feeling of bubbles	3.67±2.19^B	3.73±2.13^B	4.13±2.39^A
Taste of the product	5.27±2.27^B	4.67±1.97^C	5.80±1.71^A
				Overall preferences	5.27±2.15^B	4.67±1.58^C	5.73±1.70^A

In conclusion, since the whole performance of the litchi flower group with 0.4 wt% of litchi flower is better, the beer is prepared by adding 0.4 wt% of litchi flower and drying the litchi flower at 50 ℃ and decocting the litchi flower for 60 minutes.

(IV) adding Taiwan stalk rice into barley malt to prepare litchi flower beer

In the embodiment, different proportions of taiwan polished round-grained rice are added into barley malt to prepare saccharified cereal juice, and the used proportions are as follows: (1)50 wt% of Taiwan polished round-grained rice and 50 wt% of barley malt, (2)75 wt% of Taiwan polished round-grained rice and 25 wt% of barley malt, and (3)90 wt% of Taiwan polished round-grained rice and 10 wt% of barley malt; the sugar degree of the prepared saccharified cereal juice is 10-15 degrees Brix, and the sugar degree of the saccharified cereal juice in the embodiment is 12 degrees Brix. In this example, litchi flowers were dried at 50 ℃, added to the saccharified cereal juice at a ratio of 0.4 wt%, and boiled for 60 minutes.

Referring to fig. 12A, the initial total soluble solids content of 75 wt% taiwan polished round-grained nonglutinous group was 13.0 ° Brix, the 90 wt% taiwan polished round-grained nonglutinous group was 12.8 ° Brix, and the 50 wt% taiwan polished round-grained nonglutinous group was 11.4 ° Brix; after the ripening, the total soluble solid content of the 75 wt% taiwan polished round-grained nonglutinous rice group is reduced to the maximum extent, so that the alcohol production rate of the 75 wt% taiwan polished round-grained nonglutinous rice group is presumed to be the highest.

Referring to fig. 12B, the alcohol content of 50 wt% taiwan polished round-grained nonglutinous rice group at one-3 was 2.90%, and the alcohol content after ripening was 3.20%; the alcohol content of 75 wt% of Taiwan stalk rice group in the first-3 is 2.60%, and the alcohol content after ripening is 4.13%; the alcohol content of the 90 wt% Taiwan polished round-grained nonglutinous rice group with the alcoholicity of one-6 is 3.77%, the subsequent change is small, and the alcoholicity is 3.53% after the ripening.

Referring to table 15, the initial total saccharide content and the post-ripening total saccharide content in the saccharified cereal juice did not differ significantly between the three groups. Referring to table 16, the consumption rate of reducing saccharides was higher in the 75 wt% taiwan polished round-grained nonglutinous rice group, which was the same as the trend of the analysis result of the total soluble solid content.

Watch 15

TABLE 16

Referring to fig. 13A, the initial pH of the 50 wt% taiwan polished round-grained nonglutinous rice group was 5.15, and the pH after ripening was 3.42; the initial pH of the 75 wt% taiwan polished round-grained nonglutinous rice group was 4.99, and the pH after ripening was 3.50; the initial pH of the 90 wt% taiwan polished round-grained nonglutinous rice group was 5.80, and the pH after aging was 3.43. Referring to fig. 13B, the total acid content of the 50 wt% taiwan polished round-grained nonglutinous rice group increased with the rise of fermentation time, and was 0.36% after ripening; the total acid content of 75 wt% of Taiwan stalk group begins to decrease when the acid content is two-0, the total acid content of the Taiwan stalk group begins to increase on the third day (two-3) after sugar supplement, and the acid content is 0.31% after ripening (two-15); the total acid content of 90 wt% of Taiwan polished round-grained nonglutinous rice group in Taiwan is slowly increased after the second-3, and the content of the total acid in the ripe Taiwan polished round-grained nonglutinous rice group in the Taiwan is 0.32%. The trend of the volatile acid content of each group is the same as that of the total acid content, but all the groups meet the specification.

Referring to table 17, the total phenol content was the highest in the 50 wt% taiwan polished round-grained nonglutinous rice group and the total antioxidant capacity was the best; the 75 wt% taiwan polished round-grained nonglutinous rice group has the highest total flavonoid content; the overall performance is preferably 50 wt% of Taiwan polished round-grained rice, 75 wt% of Taiwan polished round-grained rice, and 90 wt% of Taiwan polished round-grained rice.

TABLE 17

Referring to table 18, the color evaluation results of the three groups have no significant difference, and the aroma evaluation score is from high to low 50 wt% of taiwan polished round-grained rice >75 wt% of taiwan polished round-grained rice >90 wt% of taiwan polished round-grained rice; the bubble sensation of the three groups is lower; the taste and the overall preference evaluation between the 50 wt% taiwan polished round stem group and the 75 wt% taiwan polished round stem group were not significantly different, but the overall performance of the 75 wt% taiwan polished round stem group was better, while the acceptance of the 90 wt% taiwan polished round stem group was poor, and the evaluation staff indicated that the 90 wt% taiwan polished round stem group had a very light taste and no wine sensation when drinking.

Watch 18

	50 wt% Taiwan stalk rice	75 wt% Taiwan stalk rice	90 wt% Taiwan stalk rice
				Color	5.13±2.22^B	5.73±2.32^A	5.23±2.73^B
Fragrance	5.33±2.17^A	4.73±1.87^B	4.47±1.67^C
				Feeling of bubbles	3.67±2.19^A	3.73±2.13^A	3.47±2.33^B
Taste of the product	5.27±2.27^B	5.20±2.19^A	4.20±2.14^B
				Overall preferences	5.33±2.04^A	5.47±1.55^A	4.13±1.63^B

According to the above embodiments, the method for producing a lychee flower beer of the present invention is to prepare a beer by using lychee flowers instead of hops and adding taiwan polished round-grained nonglutinous rice to barley malt, wherein the obtained lychee flower beer contains polyphenols and flavonoids, and has a taste and flavor comparable to those of the conventional beer brewed from hops and barley malt, thereby providing a new flavor beer for consumers to choose.

Claims

1. A method for producing litchi flower beer, which comprises the following steps:

the method comprises the following steps: boiling a saccharified grain juice, wherein the saccharified grain juice has a sugar degree of 10-15 DEG Brix;

step two: adding a dried litchi flower material in the boiling process of the saccharified grain juice, and continuing to boil for 30-90 minutes to obtain a litchi flower saccharified grain juice;

step three: cooling the lychee flower saccharified grain juice, adding a yeast to perform a first fermentation step, and obtaining a first fermentation product; and

step four: adding a sugar material into the first fermentation product to perform a second fermentation step to obtain the litchi flower beer.

2. The method for producing a lychee flower beer as claimed in claim 1, wherein the method for producing the saccharified cereal juice comprises: heating pure water to 70-80 ℃, adding a grain material, keeping the temperature of the pure water at 60-70 ℃ and acting for 1-3 hours to obtain the saccharified grain juice.

3. The method of claim 2, wherein the cereal material is at least one of malt and rice, and must comprise malt.

4. The method for producing a litchi flower beer as claimed in claim 1, wherein the dried litchi flower material is obtained by drying litchi flower at 0-100 ℃.

5. The method for producing a litchi flower beer as claimed in claim 4, wherein the dried litchi flower material is obtained by drying a litchi flower at 0 ℃, 50 ℃, 75 ℃ or 100 ℃.

6. The method for producing a litchi flower beer as claimed in claim 1, wherein the dried litchi flower material is added after 0 to 50 minutes from boiling of the saccharified grain juice, and further boiling is continued, and the total boiling time of the saccharified grain juice is 60 minutes.

7. The method for producing a litchi flower beer as claimed in claim 1, wherein the first fermentation step is carried out at 20 to 25 ℃ for 5 to 10 days.

8. The method for producing a lychee flower beer according to claim 1, wherein the second fermentation step is carried out at 0-10 ℃ for 10-20 days.

9. The method of claim 1, wherein the sugar material is sucrose.

10. The method for producing a lychee flower beer according to claim 1, wherein the yeast is Saccharomyces cerevisiae.