Preparation method of compound flavor nutritional rice vinegar

Abstract

The invention relates to the technical field of rice vinegar, in particular to a preparation method of compound flavor nutritional rice vinegar, which comprises the following steps: step 1, preparing materials; step 2, pretreatment; step 3, pre-fermentation; step 4, medium-term fermentation; step 5, acetic fermentation; the rice vinegar prepared by the preparation method disclosed by the invention contains more antioxidant substances including vitamin C, vitamin E and the like, and free radicals in a body can be removed through the excellent antioxidant performance of the antioxidant substances, so that cell aging can be prevented; the organic acid contained in the prepared rice vinegar can be beneficial for the body to absorb sugar, so that the sugar content in the blood can be finely reduced, the blood sugar concentration can be reduced, and diabetes can be prevented.

Description

Technical Field

[0001] The invention relates to the technical field of rice vinegar, in particular to a method for preparing composite flavor nutritious rice vinegar. Background Art

[0002] Rice vinegar is a type of vinegar, which is mainly made from millet, sorghum, glutinous rice, barley, corn and other grains.

[0003] Rice vinegar is made from grain raw materials through fermentation. It generally follows the principle of natural fermentation and does not add food additives such as acidulants, pigments and preservatives to ensure the naturalness and health of the product.

[0004] Rice vinegar is generally light red or beige in color, which is lighter than aged vinegar and darker than white vinegar.

[0005] Rice vinegar has a pure aroma and tastes sweet and sour. The sour taste is mild and the acidity is moderate, and it will not be too irritating to the mouth.

[0006] Rice vinegar is widely used in cooking and is suitable for making a variety of sweet and sour dishes, such as sweet and sour fish, sweet and sour spareribs, etc.

[0007] It can be used in cold dishes to add flavor to the dishes and make them taste richer.

[0008] It can remove the fishy smell of meat, fish and other ingredients, making the taste more delicious, and at the same time relieve the greasy feeling.

[0009] However, the rice vinegar prepared by the prior art has a relatively single flavor, and long-term use of the rice vinegar with a relatively single flavor cannot meet people's needs. Summary of the invention

[0010] In view of the problems existing in the prior art, the present invention provides a method for preparing composite flavor nutritious rice vinegar.

[0011] To achieve the above object, the present invention provides the following technical solutions: A method for preparing composite flavor nutritious rice vinegar comprises the following steps: Step 1: Prepare the ingredients: Prepare glutinous rice, quinoa and grape skins; Step 2: Preprocessing: Soaking glutinous rice; heat-treating quinoa to obtain heat-treated quinoa powder; Boil grape skins to obtain grape skin boiled water; Step 3, pre-fermentation: The heat-treated quinoa flour and grape skin boiled water are mixed and beaten in a mass ratio of 1:3-4 to obtain a mixed slurry, and the mixed slurry is pre-fermented and sterilized to obtain a preliminary fermentation product; Step 4, mid-term fermentation: The soaked glutinous rice is mixed with water in a mass ratio of 1:1 to obtain glutinous rice slurry, which is then mixed with crystal sugar and sterilized. After sterilization, yeast is added, stirred and mixed evenly, and mid-term fermentation is performed to obtain mid-term fermentation product; Step 5, acetic acid fermentation: The preliminary fermentation product and the intermediate fermentation product are mixed uniformly in a mass ratio of 1:4-5 to obtain a total fermentation product, and then Acetobacter pasteurianus is added, mixed uniformly, and acetic acid fermentation is performed. When the total acid no longer increases, the fermentation is terminated, and then vinegar is poured, and finally sterilized to obtain a finished product; Rice wine is added once during the acetic acid fermentation.

[0012] As a further technical solution, in step 1, the weight ratio of glutinous rice, quinoa and grape skin is 100:8-10:2-3.

[0013] As a further technical solution, the glutinous rice is soaked in step 2 as follows: Mix the glutinous rice and water until the water level is 12cm higher than the glutinous rice. Soak at room temperature for 8-10 hours, then filter and drain. The specific method of heat treatment of quinoa is: Quinoa powder and 5 wt % citric acid solution were mixed in a mass ratio of 1:10, stirred at room temperature for 1 hour, and then the pH of the system was adjusted to neutral to obtain a pretreated slurry; Adding delipidase to the pretreated slurry for enzymatic hydrolysis for 4 hours at a hydrolysis temperature of 40°C, then inactivating the enzyme at 100°C for 10 minutes, and finally drying and crushing to obtain pretreated quinoa powder; Among them, the amount of delipidase added was 3% of the mass of the pretreated slurry; The pretreated quinoa flour is extruded and puffed by a twin-screw extruder for 40-45 minutes, and then discharged to obtain heat-treated quinoa flour.

[0014] As a further technical solution, the parameters of the twin-screw extruder are set as follows: zone I is 85°C, zone II is 120°C, zone III is 130°C, and the screw speed is set to 180r / min; Zone Ⅰ, Zone Ⅱ and Zone Ⅲ are all carried out under nitrogen atmosphere.

[0015] As a further technical solution, the grape skin is boiled in water as follows: Mix grape skins and water in a solid-liquid ratio of 1:10, then heat to boiling, boil for 20 minutes, let stand for 2 hours, filter, remove the grape skins, and obtain grape skin boiled water.

[0016] As a further technical solution, the pre-fermentation of the mixed slurry is as follows: Add Bifidobacterium lactis 80 to the mixed slurry, stir and mix evenly, and ferment at 37° C. for 10-12 hours; Among them, Bifidobacterium lactis 80 was freeze-dried strain powder, which was added by direct injection, and the addition amount of freeze-dried strain powder was 1wt%; the content of live Lactobacillus 80 in freeze-dried strain powder was 1.2×10 7 CFU / g.

[0017] As a further technical solution, the glutinous rice paste and crystal sugar are mixed in a mass ratio of 10:1; The amount of yeast added is 0.3-0.4wt‰ of the total mass of glutinous rice paste; As a further technical solution, the mid-term fermentation temperature is 35°C and the time is 3-4 days.

[0018] As a further technical solution, the amount of Acetobacter pasteurianus added is 0.3-0.4wt% of the total amount of the fermentation product; The temperature of acetic acid fermentation is 28-30℃; Acetobacter pasteurianus is freeze-dried strain powder; the content of live Acetobacter pasteurianus in the freeze-dried strain powder is 1.0×10 6 CFU / g.

[0019] As a further technical solution, rice wine is added once during the acetic acid fermentation: Specifically, it is added after 1-1.5 hours of acetic acid fermentation; The amount of rice wine added was 5wt%; The alcohol content of the rice wine is 7.0-7.8% vol, and the total acidity is 0.80-0.85 g / 100 mL.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The rice vinegar prepared by the present invention contains a relatively high content of antioxidant substances, including vitamin C, vitamin E, etc., which can remove free radicals in the body through their excellent antioxidant properties, thereby preventing cell aging; the organic acids contained in the prepared rice vinegar can be beneficial for the body to absorb sugar, thereby significantly reducing the sugar content in the blood, reducing the blood sugar concentration, and helping to prevent diabetes.

[0021] The active ingredients in the rice vinegar prepared by the invention can promote the secretion of gastric juice and enhance gastrointestinal motility, thereby further promoting the digestion and absorption of food by the stomach and intestines.

[0022] The rice vinegar prepared by the invention has a certain antibacterial effect, can remove pathogenic bacteria, and has an inhibitory or killing effect on some harmful intestinal microorganisms.

[0023] The overall flavor of rice vinegar is mainly composed of two parts: smell and taste, including volatile components and non-volatile components, which are derived from the chemical reaction between the raw material itself and the metabolites or substances of microorganisms. In the rice vinegar preparation method of the present invention, the volatile components and non-volatile components can be greatly enriched, wherein organic acid is an important component of the taste of rice vinegar, and the rice vinegar prepared by the present invention contains a variety of organic acids, including oxalic acid, acetic acid, tartaric acid, pyruvic acid, pyroglutamic acid, tartaric acid, and lactic acid, which can improve the flavor of vinegar, soften the sourness, and enhance the sweetness and umami taste; wherein, the introduction of lactic acid makes the prepared rice vinegar taste softer, and the joint action of a variety of organic acids also greatly improves the flavor of rice vinegar and increases the flavor layering.

[0024] The present invention can help optimize the organic acid composition of rice vinegar and improve the flavor quality through pre-fermentation treatment, and plays a significant role in promoting the improvement of the quality and flavor of rice vinegar.

[0025] The invention heat-treats quinoa and then pre-fermentates the quinoa by boiling grape skins in water, thereby promoting the subsequent rice vinegar fermentation process to produce more flavor substances and accumulate more non-volatile acids, thereby forming a richer flavor layer.

[0026] The types of volatile compounds of acids, esters, ketones and phenols in the rice vinegar prepared by the present invention are significantly improved, including ethyl acetate, geranylacetone, butyl acetate, phenylethyl propyl ester, 2-hydroxy-3-pentanone, isobutyl alcohol, ethyl caproate, 2,4-dimethylbenzaldehyde, vinyl acetate, vanillin, isobutyl acetate and the like, wherein 2,4-dimethylbenzaldehyde has a bitter almond flavor, and vinyl acetate has a sweet ether flavor; ethyl acetate, geranylacetone, butyl acetate and phenylethyl propyl ester have a pleasant floral and fruity aroma; ethyl lactate has a rum, fruit and cream aroma; 2-hydroxy-3-pentanone, isobutyl alcohol and ethyl caproate have a fruity flavor; vanillin has a milky flavor; and isobutyl acetate has a raw pear and raspberry aroma. It can be seen that the rice vinegar prepared by the present invention has a strong sense of flavor hierarchy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0028] Figure 1 This is a statistical chart of total esters in each experimental group. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Bifidobacterium lactis 80 (Bla80), Micro-Con Probiotics (Suzhou) Co., Ltd.; Acetobacter pasteurianus, Bioengineering Laboratory, Shanxi Agricultural University; The following are specific embodiments: Example 1 A method for preparing composite flavor nutritious rice vinegar comprises the following steps: Step 1: Prepare the ingredients: Prepare glutinous rice, quinoa and grape skin; the weight ratio of glutinous rice, quinoa and grape skin is 100:8:2.

[0031] Step 2: Preprocessing: Soaking glutinous rice; heat-treating quinoa to obtain heat-treated quinoa powder; Boil grape skins to obtain grape skin boiled water; The glutinous rice is soaked as follows: Mix the glutinous rice and water until the water level is 12cm higher than the glutinous rice. Soak for 8 hours at room temperature, then filter and drain. The specific method of heat treatment of quinoa is: Quinoa powder and 5 wt % citric acid solution were mixed in a mass ratio of 1:10, stirred at room temperature for 1 hour, and then the pH of the system was adjusted to neutral to obtain a pretreated slurry; Adding delipidase to the pretreated slurry for enzymatic hydrolysis for 4 hours at a hydrolysis temperature of 40°C, then inactivating the enzyme at 100°C for 10 minutes, and finally drying and crushing to obtain pretreated quinoa powder; Among them, the amount of delipidase added was 3% of the mass of the pretreated slurry; The pretreated quinoa flour was extruded and puffed by a twin-screw extruder for 40 minutes, and then discharged to obtain heat-treated quinoa flour.

[0032] The parameters of the twin-screw extruder were set as follows: zone I was 85°C, zone II was 120°C, zone III was 130°C, and the screw speed was set to 180 r / min; Zone Ⅰ, Zone Ⅱ and Zone Ⅲ are all carried out under nitrogen atmosphere.

[0033] The grape skins are boiled as follows: Mix grape skins and water in a solid-liquid ratio of 1:10, then heat to boiling, boil for 20 minutes, let stand for 2 hours, filter, remove the grape skins, and obtain grape skin boiled water.

[0034] Step 3, pre-fermentation: The heat-treated quinoa flour and grape skin boiled water are mixed and beaten in a mass ratio of 1:3 to obtain a mixed slurry, and the mixed slurry is pre-fermented and sterilized to obtain a preliminary fermentation product; The mixed slurry is pre-fermented as follows: Add Bifidobacterium lactis 80 to the mixed slurry, stir and mix evenly, and ferment at 37° C. for 10 hours; Among them, Bifidobacterium lactis 80 was freeze-dried strain powder, which was added by direct injection, and the addition amount of freeze-dried strain powder was 1wt%; the content of live Lactobacillus 80 in freeze-dried strain powder was 1.2×10 7 CFU / g.

[0035] Step 4, mid-term fermentation: The soaked glutinous rice and water are mixed and ground in a mass ratio of 1:1 to obtain glutinous rice slurry, which is then mixed with crystal sugar and sterilized. After sterilization, yeast is added and stirred to mix evenly to perform mid-term fermentation to obtain mid-term fermentation product; the glutinous rice slurry and crystal sugar are mixed in a mass ratio of 10:1; The amount of yeast added was 0.3wt‰ of the total mass of glutinous rice paste; The mid-term fermentation temperature is 35℃ and the time is 3 days.

[0036] Step 5, acetic acid fermentation: The preliminary fermentation product and the intermediate fermentation product are mixed evenly in a mass ratio of 1:4 to obtain a total fermentation product, and then Acetobacter pasteurianus is added, mixed evenly, and then acetic acid fermentation is performed. When the total acid no longer increases, the fermentation is terminated, and then vinegar is poured, and finally sterilized to obtain a finished product; Rice wine is added once during the acetic acid fermentation.

[0037] The amount of Acetobacter pasteurianus added was 0.3 wt% of the total fermentation product; The temperature of acetic acid fermentation is 28°C; Acetobacter pasteurianus is freeze-dried strain powder; the content of live Acetobacter pasteurianus in the freeze-dried strain powder is 1.0×10 6 CFU / g.

[0038] Add rice wine once during acetic acid fermentation: Specifically, it is added after 1 hour of acetic acid fermentation; The amount of rice wine added was 5wt%; The alcohol content of the rice wine is 7.0% vol, and the total acidity is 0.80 g / 100 mL.

[0039] Example 2 A method for preparing composite flavor nutritious rice vinegar comprises the following steps: Step 1: Prepare the ingredients: Prepare glutinous rice, quinoa and grape skin; the weight ratio of glutinous rice, quinoa and grape skin is 100:9:2.5.

[0040] Step 2: Preprocessing: Soaking glutinous rice; heat-treating quinoa to obtain heat-treated quinoa powder; The grape skins are boiled in water to obtain grape skin boiled water; the glutinous rice is soaked as follows: Mix the glutinous rice and water until the water level is 12cm higher than the glutinous rice. Soak for 9 hours at room temperature, then filter and drain. The specific method of heat treatment of quinoa is: Quinoa powder and 5 wt % citric acid solution were mixed in a mass ratio of 1:10, stirred at room temperature for 1 hour, and then the pH of the system was adjusted to neutral to obtain a pretreated slurry; Adding delipidase to the pretreated slurry for enzymatic hydrolysis for 4 hours at a hydrolysis temperature of 40°C, then inactivating the enzyme at 100°C for 10 minutes, and finally drying and crushing to obtain pretreated quinoa powder; Among them, the amount of delipidase added was 3% of the mass of the pretreated slurry; The pretreated quinoa flour was extruded and puffed for 45 minutes using a twin-screw extruder, and then discharged to obtain heat-treated quinoa flour.

[0041] The parameters of the twin-screw extruder were set as follows: zone I was 85°C, zone II was 120°C, zone III was 130°C, and the screw speed was set to 180 r / min; Zone Ⅰ, Zone Ⅱ and Zone Ⅲ are all carried out under nitrogen atmosphere.

[0042] The grape skins are boiled as follows: Mix grape skins and water in a solid-liquid ratio of 1:10, then heat to boiling, boil for 20 minutes, let stand for 2 hours, filter, remove the grape skins, and obtain grape skin boiled water.

[0043] Step 3, pre-fermentation: Heat-treated quinoa powder and grape skin boiled water are mixed and pulped in a mass ratio of 1:3.5 to obtain a mixed slurry, and the mixed slurry is pre-fermented and sterilized to obtain a preliminary fermentation product; the mixed slurry is pre-fermented to: Add Bifidobacterium lactis 80 to the mixed slurry, stir and mix evenly, and ferment at 37° C. for 11 hours; Among them, Bifidobacterium lactis 80 was freeze-dried strain powder, which was added by direct injection, and the addition amount of freeze-dried strain powder was 1wt%; the content of live Lactobacillus 80 in freeze-dried strain powder was 1.2×10 7 CFU / g.

[0044] Step 4, mid-term fermentation: The soaked glutinous rice and water are mixed and ground in a mass ratio of 1:1 to obtain glutinous rice slurry, which is then mixed with crystal sugar and sterilized. After sterilization, yeast is added and stirred to mix evenly to perform mid-term fermentation to obtain mid-term fermentation product; the glutinous rice slurry and crystal sugar are mixed in a mass ratio of 10:1; The amount of yeast added was 0.34wt‰ of the total mass of glutinous rice paste; The mid-term fermentation temperature is 35℃ and the time is 3.5 days.

[0045] Step 5, acetic acid fermentation: The preliminary fermentation product and the intermediate fermentation product are mixed uniformly in a mass ratio of 1:4.5 to obtain a total fermentation product, and then Acetobacter pasteurianus is added, mixed uniformly, and acetic acid fermentation is performed. When the total acid no longer increases, the fermentation is terminated, and then vinegar is poured, and finally sterilized to obtain a finished product; Rice wine is added once during the acetic acid fermentation.

[0046] The amount of Acetobacter pasteurianus added was 0.38 wt% of the total fermentation product; The temperature of acetic acid fermentation is 28°C; Acetobacter pasteurianus is freeze-dried strain powder; the content of live Acetobacter pasteurianus in the freeze-dried strain powder is 1.0×10 6 CFU / g.

[0047] Add rice wine once during acetic acid fermentation: Specifically, it is added after 1.2 hours of acetic acid fermentation; The amount of rice wine added was 5wt%; The alcohol content of the rice wine is 7.5% vol, and the total acidity is 0.83 g / 100 mL.

[0048] Example 3 A method for preparing composite flavor nutritious rice vinegar comprises the following steps: Step 1: Prepare the ingredients: Prepare glutinous rice, quinoa and grape skin; the weight ratio of glutinous rice, quinoa and grape skin is 100:10:3.

[0049] Step 2: Preprocessing: Soaking glutinous rice; heat-treating quinoa to obtain heat-treated quinoa powder; The grape skins are boiled in water to obtain grape skin boiled water; the glutinous rice is soaked as follows: Mix the glutinous rice and water until the water level is 12cm higher than the glutinous rice. Soak for 10 hours at room temperature, then filter and drain. The specific method of heat treatment of quinoa is: Quinoa powder and 5 wt % citric acid solution were mixed in a mass ratio of 1:10, stirred at room temperature for 1 hour, and then the pH of the system was adjusted to neutral to obtain a pretreated slurry; Adding delipidase to the pretreated slurry for enzymatic hydrolysis for 4 hours at a hydrolysis temperature of 40°C, then inactivating the enzyme at 100°C for 10 minutes, and finally drying and crushing to obtain pretreated quinoa powder; Among them, the amount of delipidase added was 3% of the mass of the pretreated slurry; The pretreated quinoa flour was extruded and puffed for 45 minutes using a twin-screw extruder, and then discharged to obtain heat-treated quinoa flour.

[0050] The parameters of the twin-screw extruder were set as follows: zone I was 85°C, zone II was 120°C, zone III was 130°C, and the screw speed was set to 180 r / min; Zone Ⅰ, Zone Ⅱ and Zone Ⅲ are all carried out under nitrogen atmosphere.

[0051] The grape skins are boiled as follows: Mix grape skins and water in a solid-liquid ratio of 1:10, then heat to boiling, boil for 20 minutes, let stand for 2 hours, filter, remove the grape skins, and obtain grape skin boiled water.

[0052] Step 3, pre-fermentation: Heat-treated quinoa powder and grape skin boiled water are mixed and pulped in a mass ratio of 1:4 to obtain a mixed slurry, and then the mixed slurry is pre-fermented and sterilized to obtain a preliminary fermentation product; the mixed slurry is pre-fermented to: Add Bifidobacterium lactis 80 to the mixed slurry, stir and mix evenly, and ferment at 37° C. for 12 hours; Among them, Bifidobacterium lactis 80 was freeze-dried strain powder, which was added by direct injection, and the addition amount of freeze-dried strain powder was 1wt%; the content of live Lactobacillus 80 in freeze-dried strain powder was 1.2×10 7 CFU / g.

[0053] Step 4, mid-term fermentation: The soaked glutinous rice and water are mixed and ground in a mass ratio of 1:1 to obtain glutinous rice slurry, which is then mixed with crystal sugar and sterilized. After sterilization, yeast is added and stirred to mix evenly to perform mid-term fermentation to obtain mid-term fermentation product; the glutinous rice slurry and crystal sugar are mixed in a mass ratio of 10:1; The amount of yeast added was 0.4wt‰ of the total mass of glutinous rice paste; The mid-term fermentation temperature is 35℃ and the time is 4 days.

[0054] Step 5, acetic acid fermentation: The preliminary fermentation product and the intermediate fermentation product are mixed uniformly in a mass ratio of 1:5 to obtain a total fermentation product, and then Acetobacter pasteurianus is added, mixed uniformly, and then acetic acid fermentation is performed. When the total acid no longer increases, the fermentation is terminated, and then vinegar is poured, and finally sterilized to obtain a finished product; Rice wine is added once during the acetic acid fermentation.

[0055] The amount of Acetobacter pasteurianus added was 0.4 wt% of the total fermentation product; The temperature of acetic acid fermentation is 30°C; Acetobacter pasteurianus is freeze-dried strain powder; the content of live Acetobacter pasteurianus in the freeze-dried strain powder is 1.0×10 6 CFU / g.

[0056] Add rice wine once during acetic acid fermentation: Specifically, it is added after 1.5 hours of acetic acid fermentation; The amount of rice wine added was 5wt%; The alcohol content of the rice wine is 7.8% vol, and the total acidity is 0.85 g / 100 mL.

[0057] Comparative Example 1: This comparative example is basically the same as Example 2, except that quinoa is not heat-treated.

[0058] Comparative Example 2: This comparative example is substantially the same as Example 2, except that no pre-fermentation treatment is performed.

[0059] Comparative Example 3: This comparative example is substantially the same as Example 2, except that no rice wine is added during fermentation.

[0060] Comparative Example 4: This comparative example is basically the same as Example 2, except that Zone I, Zone II and Zone III are carried out under air atmosphere.

[0061] Comparative Example 5: This comparative example is basically the same as Example 2, except that no mid-term fermentation treatment is performed.

[0062] test: The rice vinegar prepared in the embodiment and the comparative example was sent for inspection, and the total acid content was detected according to the national standard GB / T18187. The results are shown in Table 1 below. Table 1

[0063] As can be seen from Table 1, the present invention utilizes heat treatment and pre-fermentation treatment of quinoa to promote the production of acid in the fermentation process to a certain extent and increase the total acid content in rice vinegar.

[0064] The rice vinegar prepared in the embodiment and the comparative example was sent for inspection, and the total ester content was detected according to the national standard GB / T 5009.41. The results are shown in Table 2 below: Table 2

[0065] As shown in Table 2, the present invention utilizes heat treatment and pre-fermentation treatment of quinoa to promote the production of ester substances, increase the flavor of rice vinegar, and improve the flavor level of rice vinegar.

[0066] Determination of organic acids Embodiment and comparative example The organic acid of rice vinegar is determined by high performance liquid chromatography with reference to GB / T18623-2011 "National Geographical Indication Product Zhenjiang Vinegar": Table 3 Type of organic acid Organic Acid Example 1 7 Oxalic acid, acetic acid, tartaric acid, pyruvic acid, pyroglutamic acid, tartaric acid, lactic acid Example 2 7 Oxalic acid, acetic acid, tartaric acid, pyruvic acid, pyroglutamic acid, tartaric acid, lactic acid Example 3 7 Oxalic acid, acetic acid, tartaric acid, pyruvic acid, pyroglutamic acid, tartaric acid, lactic acid It can be seen from Table 3 that the rice vinegar prepared by the present invention is rich in various organic acids and provides a richer flavor.

[0067] Determination of volatile flavor components 15 mL of the rice vinegar prepared in the embodiment and the comparative example was added to a 70 mL headspace bottle, and the bottle was kept warm at 60° C. in a magnetic stirring water bath. The extraction head was inserted into the headspace bottle, and the bottle was balanced for 20 min. Then, the adsorption extraction head was pushed out for headspace adsorption for 70 min, and the head was inserted into the gas chromatograph injection port for desorption for 5 min.

[0068] Chromatographic conditions: carrier gas is high-purity helium (99.999%), constant flow rate is 1 mL / min, DB-WAX capillary column (30 m×0.25 mm×0.25 μm), injection port temperature is 250 °C, non-split injection mode; temperature program setting: temperature 40 °C, hold for 2 min, increase to 100 °C at 4 °C / min, hold for 3 min, then increase to 180 °C at 8 °C / min, hold for 2 min, and then increase to 255 °C at 25 °C / min.

[0069] Mass spectrometry conditions: ionization mode: electron ionization (EI) source, electron energy 70 eV, quadrupole temperature 150 °C, transfer line temperature 280 °C, scanning mass range: 20~550 amu, interface temperature 250 °C, ion source temperature 230 °C; Table 4 Type of volatile components Example 1 49 Example 2 49 Example 3 49 Comparative Example 1 44 Comparative Example 2 40 Comparative Example 3 47 Comparative Example 4 48 Comparative Example 5 42 It can be seen from Table 4 that the rice vinegar prepared by the present invention is rich in various volatile components, which provides a rich basis for the flavor of the rice vinegar.

[0070] Based on Example 2, the volatile components were analyzed in detail for comparison: Table 5 Volatile components Type / species Esters 20 Aldehydes 3 Ketones 3 Acids 8 Alcohols 9 Other categories 4 As can be seen from Table 5, the rice vinegar prepared by the present invention contains a variety of volatile components, which enriches its flavor.

[0071] Stability test, stored at 50℃ for 30 days, observe the changes: Table 6 stability Example 1 No turbidity or precipitation, no color change Example 2 No turbidity or precipitation, no color change Example 3 No turbidity or precipitation, no color change Comparative Example 1 Slightly turbid, no color change Comparative Example 2 Slightly turbid, a small amount of precipitation, no color change Comparative Example 3 No turbidity or precipitation, no color change Comparative Example 4 No turbidity or precipitation, no color change Comparative Example 5 No turbidity or precipitation, and slight color change As can be seen from Table 6, the rice vinegar prepared by the present invention has high temperature stability.

[0072] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing composite flavor nutritious rice vinegar, characterized in that: The following steps are involved: Step 1: Prepare the ingredients: Prepare glutinous rice, quinoa and grape skins; Step 2: Preprocessing: Soaking glutinous rice; heat-treating quinoa to obtain heat-treated quinoa powder; Boil grape skins to obtain grape skin boiled water; Step 3, pre-fermentation: The heat-treated quinoa flour and grape skin boiled water are mixed and beaten in a mass ratio of 1:3-4 to obtain a mixed slurry, and the mixed slurry is pre-fermented and sterilized to obtain a preliminary fermentation product; Step 4, mid-term fermentation: The soaked glutinous rice is mixed with water in a mass ratio of 1:1 to obtain glutinous rice slurry, which is then mixed with crystal sugar and sterilized. After sterilization, yeast is added, stirred and mixed evenly, and mid-term fermentation is performed to obtain mid-term fermentation product; Step 5, acetic acid fermentation: The preliminary fermentation product and the intermediate fermentation product are mixed uniformly in a mass ratio of 1:4-5 to obtain a total fermentation product, and then Acetobacter pasteurianus is added, mixed uniformly, and acetic acid fermentation is performed. When the total acid no longer increases, the fermentation is terminated, and then vinegar is poured, and finally sterilized to obtain a finished product; Rice wine is added once during the acetic acid fermentation.

2. The method for preparing a composite flavor nutritious rice vinegar according to claim 1, characterized in that: In step 1, the weight ratio of glutinous rice, quinoa and grape skin is 100:8-10:2-3.

3. The method for preparing a composite flavor nutritious rice vinegar according to claim 1, characterized in that: In step 2, the glutinous rice is soaked as follows: Mix the glutinous rice and water until the water level is 12cm higher than the glutinous rice. Soak at room temperature for 8-10 hours, then filter and drain. The specific method for heat treatment of quinoa is: First, the quinoa particles are dried to a moisture content of less than 15%, and then crushed and passed through a 75-mesh sieve to obtain quinoa powder; Quinoa powder and 5 wt % citric acid solution were mixed in a mass ratio of 1:10, stirred at room temperature for 1 hour, and then the pH of the system was adjusted to neutral to obtain a pretreated slurry; Adding delipidase to the pretreated slurry for enzymatic hydrolysis for 4 hours at a hydrolysis temperature of 40°C, then inactivating the enzyme at 100°C for 10 minutes, and finally drying and crushing to obtain pretreated quinoa powder; Among them, the amount of delipidase added was 3% of the mass of the pretreated slurry; The pretreated quinoa flour is extruded and puffed by a twin-screw extruder for 40-45 minutes, and then discharged to obtain heat-treated quinoa flour.

4. The method for preparing a composite flavor nutritious rice vinegar according to claim 3, characterized in that: The parameters of the twin-screw extruder are set as follows: zone I is 85°C, zone II is 120°C, zone III is 130°C, and the screw speed is set to 180r / min; Zone Ⅰ, Zone Ⅱ and Zone Ⅲ are all carried out under nitrogen atmosphere.

5. The method for preparing a composite flavor nutritious rice vinegar according to claim 1, characterized in that: The described grape skin is boiled in water and treated as follows: Mix grape skins and water in a solid-liquid ratio of 1:10, then heat to boiling, boil for 20 minutes, let stand for 2 hours, filter, remove the grape skins, and obtain grape skin boiled water.

6. The method for preparing a composite flavor nutritious rice vinegar according to claim 1, characterized in that: The mixed slurry is pre-fermented as follows: Add Bifidobacterium lactis 80 to the mixed slurry, stir and mix evenly, and ferment at 37° C. for 10-12 hours; Among them, Bifidobacterium lactis 80 was freeze-dried strain powder, which was added by direct injection, and the addition amount of freeze-dried strain powder was 1wt%; the content of live Lactobacillus 80 in freeze-dried strain powder was 1.2×10 7 CFU / g.

7. The method for preparing a composite flavor nutritious rice vinegar according to claim 1, characterized in that: The glutinous rice paste and crystal sugar are mixed in a mass ratio of 10:1; The amount of yeast added is 0.3-0.4wt‰ of the total mass of glutinous rice paste.

8. The method for preparing a composite flavor nutritious rice vinegar according to claim 7, characterized in that: The mid-term fermentation temperature is 35°C and the time is 3-4 days.

9. The method for preparing a composite flavor nutritious rice vinegar according to claim 1, characterized in that: The amount of Acetobacter pasteurianus added is 0.3-0.4wt% of the total amount of the fermented product; The temperature of acetic acid fermentation is 28-30℃; Acetobacter pasteurianus is freeze-dried strain powder; the content of live Acetobacter pasteurianus in the freeze-dried strain powder is 1.0×10 6 CFU / g.

10. The method for preparing a composite flavor nutritious rice vinegar according to claim 1, characterized in that: During the acetic acid fermentation, rice wine is added once: Specifically, it is added after 1-1.5 hours of acetic acid fermentation; The amount of rice wine added was 5wt%; The alcohol content of the rice wine is 7.0-7.8% vol, and the total acidity is 0.80-0.85 g / 100 mL.

Images