Purple yam and lotus root fermented wine and brewing method thereof

Abstract

The invention discloses purple yam and lotus root fermented wine and a brewing method thereof. The fermented wine is brewed by taking fresh Honghu lotus root and purple yam as main raw materials according to a specific weight ratio, and supplementing a compound enzyme preparation, beta-cyclodextrin, rock sugar, special distiller's yeast, a fermentation regulator, propyl gallate and chitosan. The core of the brewing method is as follows: the purple yam is subjected to high-pressure bubble cleaning to protect color and remove astringency; mixing and kneading the lotus root paste, the lotus root juice and the purple yam paste to fuse flavor precursors; a two-stage temperature-controlled fermentation process of aerobic firstly and anaerobic secondly is adopted; and chitosan is combined with a multi-tank series low-temperature clarification process for final treatment. The method effectively solves the problem that the purple yam is easy to oxidize and discolor during processing, successfully brews the special fermented wine which is purple red and stable in color, rich in flavor level (with fruit fragrance, lotus root fragrance and mellow fragrance), high in nutritional value and stable in quality, and is stable in process and suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of fermented wine brewing technology, specifically relating to a fermented wine made from purple yam and lotus root and its brewing method. Background Technology

[0002] Purple yam, a plant resource with both medicinal and edible uses, not only contains abundant starch, protein, vitamins, and other basic nutrients in its tubers, but also boasts anthocyanins, polysaccharides, saponins, and various trace elements not found in ordinary yams. These active ingredients endow purple yam with excellent antioxidant and immune-boosting physiological functions, giving it high nutritional and health value. Furthermore, the unique natural pigments and fruity flavor of purple yam demonstrate broad potential in the food development field, especially in specialty fermented beverages.

[0003] Lotus root, especially the high-quality lotus root from the Honghu region, is also a nutritious food, containing a large amount of starch, dietary fiber, and various minerals. Using lotus root as a raw material and its abundant sugars to brew fermented wine through microbial fermentation technology has already seen some basic research and product development. These products aim to retain the delicate fragrance of lotus root while developing a mellow aroma through fermentation, creating a unique flavor.

[0004] However, current lotus root fermented wine products on the market have relatively simple flavor profiles, mainly relying on the natural fragrance of lotus root and the aroma of alcohol produced during fermentation. The nutritional value of these products is also largely limited to the basic components of lotus root. Directly introducing purple yam into the fermentation system faces technical challenges: the polyphenols (such as anthocyanins) in purple yam are easily deactivated and discolored due to oxidation during processing and storage, resulting in a dull color, damaged flavor, and a reduction in its unique health benefits. Furthermore, purple yam and lotus root differ in texture, sugar composition, and flavor compound release characteristics. How to organically combine the two to achieve complementary flavors and synergistic nutritional enhancement during fermentation, rather than simply mixing them, is a technical challenge. Summary of the Invention

[0005] The present invention aims to provide a fermented wine made from purple yam and lotus root and its brewing method, which solves the technical problems of the existing lotus root fermented wine having a single flavor and low nutritional added value, as well as the purple yam being prone to oxidation and discoloration during processing, and the difficulty in effectively integrating and preserving its flavor.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A fermented wine made from purple yam and lotus root comprises the following raw materials in parts by weight: 100-120 parts fresh Honghu lotus root, 0.2-0.4 parts compound enzyme preparation, 5-8 parts β-cyclodextrin, 100-120 parts rock sugar, 1.0-1.2 parts special yeast, 0.3-0.5 parts fermentation regulator, 0.05-0.1 parts propyl gallate, 1-1.5 parts chitosan, and 25-30 parts purple yam, wherein the weight ratio of purple yam to fresh Honghu lotus root is 1:4.

[0007] Furthermore, the compound enzyme preparation is composed of α-amylase, pectinase, and cellulase in a mass ratio of 3-5:2-4:1-2.

[0008] Furthermore, the fermentation regulator is composed of potassium hydrogen tartrate and magnesium sulfate in a mass ratio of 3-5:2-3.

[0009] Furthermore, the specially made yeast is a compound of Rhizopus and rice yeast, wherein the mass ratio of Rhizopus to rice yeast is 1:1 to 2:1.

[0010] Furthermore, the chitosan is selected from one or more of deacetylated chitin, oligochitosan, and water-soluble chitosan, with a degree of deacetylation ≥90%.

[0011] A method for brewing fermented wine from purple yam and lotus root includes the following steps: (1) Raw material pretreatment: Select high-quality fresh lotus root and purple yam from Honghu Lake, remove the lotus root skin and nodes from the lotus root and the yam skin and ends from the purple yam, and wash them for later use; (2) Cutting and cleaning: Cut the pre-treated lotus root and purple yam into chunks, clean them twice with purified water, and then air dry them until the moisture content is ≤10%; (3) Making mud and extracting juice: The dried lotus root pieces and purple yam pieces are physically pressed to obtain lotus root mud and purple yam mud respectively; some of the lotus root mud is further pressed to obtain lotus root juice; (4) Mix fermentation materials: Mix the lotus root paste, lotus root juice, purple yam paste obtained in step (3) with rock sugar and special yeast in proportion, stir evenly, and obtain the fermentation mixture materials; (5) Primary fermentation: Inoculate the fermentation mixture with brewing yeast, and carry out aerobic fermentation under the condition of introducing sterile air and stirring. The fermentation time is 10 days to obtain the primary fermentation product. (6) Secondary fermentation and aging: The primary fermentation product is sealed and anaerobic fermented for 15-20 days, and then the wine and lees are separated; the separated wine is transferred to an aging tank for sealed aging. (7) Clarification and bottling: The aged wine is processed through a multi-tank series low-temperature clarification process to obtain clarified purple yam and lotus root fermented wine, which is then bottled.

[0012] Furthermore, in step (2), the lotus root pieces and purple yam pieces are cut to a size of 3-5cm; the bubble pressure of the secondary bubble cleaning is 0.1-0.3MPa, and the cleaning time is 5-10 minutes.

[0013] Furthermore, in step (5), the amount of brewing yeast inoculated is 0.5-1.0% of the total weight of the fermentation mixture; the aerobic fermentation temperature is 18-20℃; the daily ventilation rate of sterile air is 0.4-0.6 L / min; and the mixture is stirred 1-2 times a day for 15-20 minutes each time.

[0014] Furthermore, in step (6), the temperature of the sealed anaerobic fermentation is 22-24℃; the lees are separated by plate and frame filtration, and the filtration pressure is 0.2-0.5MPa; the inner wall of the aging vat is coated with nano titanium dioxide; the aging temperature is 18-22℃, and the aging time is 28-32 days.

[0015] Furthermore, in step (7), the multi-tank series low-temperature clarification process adopts a five-stage series container tank clarification system based on the principle of connected pressure: first, the wine juice obtained by manual physical pressing after fermentation is mixed with the reserved primary fermentation product and pumped into the clarification tank for preliminary filtration. Then, the wine juice is continuously passed through five series-connected container tanks under the action of system pressure difference. Impurities are removed through staged low-temperature sedimentation and physical filtration to obtain clear wine.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention scientifically combines purple yam and lotus root in a specific ratio (1:4) and uses a process of simultaneous mixing of "lotus root paste, lotus root juice, and yam paste" to fully integrate and permeate the unique fruity aroma of purple yam and the fragrance of lotus root before fermentation. During fermentation, under the action of compound enzyme preparations (amylase, pectinase, and cellulase working together) and specially made rhizobium-rice koji, the flavor precursors in the raw materials are fully released and transformed, ultimately forming a unique compound flavor with rich layers and a combination of fruity, mellow, and lotus root aromas. At the same time, to address the problem of easy oxidation and discoloration of anthocyanins in purple yam, a secondary high-pressure bubble cleaning is used to quickly remove surface astringent substances and oxidases. Combined with the addition of β-cyclodextrin to molecularly encapsulate and protect anthocyanins, and the use of chitosan to assist in clarification and stabilization after fermentation, the finished wine presents a stable and bright purple-red color with excellent sensory quality.

[0017] (2) This invention not only retains the inherent nutrients such as starch, dietary fiber, and vitamins in lotus root and purple yam, but also transforms some macromolecular substances into more easily absorbed small molecules through fermentation. In particular, the optimized mild process maximizes the retention of bioactive components such as anthocyanins, polysaccharides, and saponins in purple yam, giving the product potential antioxidant and immune-enhancing health benefits, thus upgrading it from ordinary fermented wine to a nutritionally fortified specialty beverage.

[0018] (3) To address the industry-wide problem of browning and residual astringent taste in purple yam processing, this invention creatively employs a pure water bubble cleaning process with specific pressure and time. This step can efficiently and physically peel off and wash away substances on the surface of the yam that cause astringency and oxidation, thus inhibiting quality deterioration from the source. Combined with the subsequent staged temperature and oxygen-controlled fermentation system (aerobic first, then anaerobic), the optimal metabolic environment is provided for the brewing yeast and microorganisms in the koji. This not only ensures a stable and thorough fermentation process but also effectively inhibits contamination by miscellaneous bacteria and the generation of undesirable flavor substances, guaranteeing the uniformity and stability of batch product quality.

[0019] (4) This invention adopts a model of "partially extracting juice from lotus root mud, with the remaining lotus root mud directly participating in fermentation". On the one hand, the lotus root juice provides sugar and water that are easily utilized by yeast, accelerating the start of fermentation; on the other hand, the retained lotus root mud and yam mud increase the solid content of the fermentation substrate, making the extraction of flavor substances and nutrients into the wine more complete. The use of compound enzyme preparations effectively destroys the plant cell walls and promotes the dissolution of contents, thereby increasing the yield and effective component content of the final wine under the same raw material input.

[0020] (5) In response to the technical challenge of purple yam being prone to oxidation and discoloration, an innovative bubble cleaning process was used to effectively control the process from the source. Combined with staged temperature-controlled fermentation and multi-tank series low-temperature clarification process, the stability of the production process and the consistency of product quality were ensured. At the same time, low-temperature clarification better preserved the flavor active substances of the wine.

[0021] (6) The raw material ratio provided by the present invention is clear, the process flow steps are clear, and the preferred ranges of key process parameters (such as temperature, pressure, time and ratio) are given. Furthermore, mature and reliable food processing equipment such as plate and frame filter press and multi-tank series low temperature clarification process are adopted. The whole solution is easy to achieve standardized and large-scale production in food processing enterprises and has good industrial transformation prospects. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The present invention will be further described in detail below with reference to the embodiments. Example 1

[0024] A fermented wine made from purple yam and lotus root comprises the following ingredients in parts by weight: 100 parts fresh Honghu lotus root, 25 parts purple yam (pure wild variety from Wuxue, Hubei), 0.3 parts compound enzyme preparation, 6 parts β-cyclodextrin, 110 parts rock sugar, 1.1 parts special yeast, 0.4 parts fermentation regulator, 0.07 parts propyl gallate, and 1.2 parts chitosan.

[0025] The compound enzyme preparation is composed of α-amylase, pectinase and cellulase in a mass ratio of 4:3:1.5. The special yeast is composed of rhizobium and rice yeast in a mass ratio of 1.5:1. The fermentation regulator is composed of potassium hydrogen tartrate and magnesium sulfate in a mass ratio of 4:2.5. The chitosan is selected from oligochitosan with a deacetylation degree ≥95%.

[0026] A method for brewing fermented wine from purple yam and lotus root includes the following steps: (1) Raw material pretreatment Rinse 100 portions of fresh Honghu lotus root and 25 portions of purple yam under running water to remove surface mud and sand. Manually remove the lotus root skin and nodes, and the purple yam skin and both ends.

[0027] (2) Cutting, washing and drying Cut the peeled lotus root and purple yam into approximately 4cm cubes. Place the cubes in a purified water bubble washing machine and wash them twice under 0.2MPa pressure for 8 minutes each time to thoroughly remove the astringent taste of the purple yam and slow down oxidation. After washing, place them in a well-ventilated and clean environment to air dry until the surface moisture content of the materials drops to approximately 9%.

[0028] (3) Making mud, extracting juice and mixing After drying, all the lotus root pieces are physically pressed to obtain lotus root paste. 50 portions of the lotus root paste are set aside, and the remaining lotus root paste is further pressed and separated by filtration to obtain 50 portions of lotus root juice.

[0029] After drying, mash all the purple yam pieces into a fine purple yam paste.

[0030] In a clean fermentation container, add 50 parts lotus root paste, 50 parts lotus root juice, 25 parts purple yam paste, 110 parts rock sugar, and 1.1 parts special yeast, prepared in step (1). Stir and knead thoroughly until the materials are evenly mixed to form a fermentation mixture. This process allows the fruity aroma of purple yam and the fragrance of lotus root to fully contact and permeate.

[0031] (4) Primary (aerobic) fermentation Inoculate the fermentation mixture with dry brewing yeast at an inoculation rate of 0.8% of the total material weight. Place the fermentation vessel in a constant temperature environment of 18.5℃ for open fermentation. Introduce sterile air daily through a sterile air distribution system at a flow rate of 0.5 L / min for 30 minutes, and mechanically stir twice, for 18 minutes each time. Continue this process for 10 days to obtain the primary fermentation product.

[0032] (5) Secondary (anaerobic) fermentation and aging The primary fermentation products were transferred to sealed fermentation tanks and subjected to strict anaerobic fermentation at 23°C for 18 days. After fermentation, a plate and frame filter press was used to separate the wine from the lees at a pressure of 0.35 MPa. The clarified wine was then transferred to aging tanks with an inner wall coated with nano-titanium dioxide and sealed tightly. The wine was then aged for 30 days in a constant-temperature aging room at 20°C.

[0033] (6) Clarification and filling After aging, 1.2 parts of the aforementioned chitosan are added to the wine, gently stirred to aid dissolution, and allowed to stand for 24 hours for preliminary flocculation and clarification. Then, the wine is pumped into a clarification tank for preliminary filtration. Subsequently, the wine is passed sequentially through five tanks connected in series under the pressure difference of the system, removing impurities through staged low-temperature sedimentation and physical filtration to obtain a clear wine. Example 2

[0034] The brewing steps in this embodiment are exactly the same as those in Example 1, except that the following raw material ratios are adjusted (by weight): 120 parts fresh Honghu lotus root, 30 parts purple yam, 120 parts rock sugar, 0.25 parts compound enzyme preparation (α-amylase, pectinase, cellulase in a mass ratio of 3.5:2.5:1), and 1.0 part special yeast (rhizome and rice yeast are mixed in a mass ratio of 1:1).

[0035] The product obtained in this embodiment has a more prominent lotus root flavor, a slightly refreshing body, and a slightly lighter color from the purple yam. The overall style is slightly different from that of Example 1, reflecting the adjustability of the formula ratio. Example 3

[0036] This embodiment uses the same raw material ratio as Example 1, but optimizes some process parameters to explore their impact on product flavor: During the washing process, the bubble washing pressure is increased to 0.28 MPa and the time is shortened to 6 minutes. This is more conducive to quickly removing the astringent substances from the purple yam skin. During the primary fermentation process, the temperature is controlled at 20℃, the inoculation amount of brewing yeast is 1.0%, and stirring is only once a day for 20 minutes each time. These conditions help to produce a richer ester aroma. During aging, the aging time is extended to 60 days.

[0037] The resulting product has a more complex and richer aroma and a smoother, more rounded taste, demonstrating the positive effect of extending the aging time on improving the quality of the wine.

[0038] Comparative Example 1 (using only lotus root) Without adding purple yam, the lotus root portion was increased to 125 parts, and the rest of the formula and steps were the same as in Example 1. The resulting product was a traditional lotus root wine, with a light yellow color and a simple flavor. It lacked the unique fruity aroma, anthocyanin color, and health-promoting components of purple yam, and the antioxidant stability test showed that its polyphenol retention rate was significantly lower than that of the product of this invention.

[0039] Comparative Example 2 (purple yam without secondary bubble washing treatment) After peeling and cutting the purple yam into chunks, it was simply soaked and rinsed in purified water without undergoing pressure bubble washing. The rest of the process was the same as in Example 1. The resulting product showed a significant color change to grayish-brown during the later stages of fermentation, and a slight astringent taste was perceptible in the finished wine, demonstrating the crucial role of secondary bubble washing in protecting the color of the purple yam and removing its astringent taste.

[0040] Effect description: As demonstrated by the above examples and comparative examples, this invention, through a specific ratio of purple yam and lotus root, combined with targeted raw material pretreatment (especially secondary bubble washing of the purple yam), the synergistic use of compound enzymes and fermentation regulators, staged temperature and oxygen-controlled fermentation, and nanomaterial-assisted aging, successfully brewed a purple yam and lotus root fermented wine with a stable purplish-red color, complex fruity and mellow aroma, unique flavor, rich nutrition, and consistent quality. This invention effectively solves the problems of oxidation and discoloration and flavor loss of purple yam during processing, achieving complementary advantages between the two raw materials.

[0041] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fermented wine made from purple yam and lotus root, characterized in that, The ingredients consist of the following components by weight: 100-120 parts fresh Honghu lotus root, 0.2-0.4 parts compound enzyme preparation, 5-8 parts β-cyclodextrin, 100-120 parts rock sugar, 1.0-1.2 parts special yeast, 0.3-0.5 parts fermentation regulator, 0.05-0.1 parts propyl gallate, 1-1.5 parts chitosan, and 25-30 parts purple yam. The weight ratio of purple yam to fresh Honghu lotus root is 1:

4.

2. The purple yam and lotus root fermented wine according to claim 1, characterized in that, The compound enzyme preparation is composed of α-amylase, pectinase, and cellulase in a mass ratio of 3-5:2-4:1-2.

3. The purple yam and lotus root fermented wine according to claim 1, characterized in that, The fermentation regulator is composed of potassium hydrogen tartrate and magnesium sulfate in a mass ratio of 3-5:2-3.

4. The purple yam and lotus root fermented wine according to claim 1, characterized in that, The specially made yeast is a compound of rhizobium and rice yeast, wherein the mass ratio of rhizobium to rice yeast is 1:1 to 2:

1.

5. The purple yam and lotus root fermented wine according to claim 1, characterized in that, The chitosan is selected from one or more of deacetylated chitin, oligochitosan, and water-soluble chitosan, with a degree of deacetylation ≥90%.

6. A method for brewing fermented wine from purple yam and lotus root, characterized in that, Includes the following steps: (1) Raw material pretreatment: Select high-quality fresh lotus root and purple yam from Honghu Lake, remove the lotus root skin and nodes from the lotus root and the yam skin and ends from the purple yam, and wash them for later use; (2) Cutting and cleaning: Cut the pre-treated lotus root and purple yam into chunks, clean them twice with purified water, and then air dry them until the moisture content is ≤10%; (3) Making mud and extracting juice: The dried lotus root pieces and purple yam pieces are physically pressed to obtain lotus root mud and purple yam mud respectively; some of the lotus root mud is further pressed to obtain lotus root juice; (4) Mix fermentation materials: Mix the lotus root paste, lotus root juice, purple yam paste obtained in step (3) with rock sugar and special yeast in proportion, stir evenly, and obtain the fermentation mixture materials; (5) Primary fermentation: Inoculate the fermentation mixture with brewing yeast, and carry out aerobic fermentation under the condition of introducing sterile air and stirring. The fermentation time is 10 days to obtain the primary fermentation product. (6) Secondary fermentation and aging: The primary fermentation product is sealed and anaerobic fermented for 15-20 days, and then the wine and lees are separated; the separated wine is transferred to an aging tank for sealed aging. (7) Clarification and bottling: The aged wine is processed through a multi-tank series low-temperature clarification process to obtain clarified purple yam and lotus root fermented wine, which is then bottled.

7. The brewing method for a purple yam and lotus root fermented wine according to claim 6, characterized in that, In step (2), the lotus root pieces and purple yam pieces are cut to a size of 3-5cm; the bubble pressure of the secondary bubble cleaning is 0.1-0.3MPa, and the cleaning time is 5-10 minutes.

8. The brewing method for a purple yam and lotus root fermented wine according to claim 6, characterized in that, In step (5), the amount of brewing yeast inoculated is 0.5-1.0% of the total weight of the fermentation mixture; the aerobic fermentation temperature is 18-20℃; the daily ventilation rate of sterile air is 0.4-0.6 L / min; and the mixture is stirred 1-2 times a day for 15-20 minutes each time.

9. The brewing method for a fermented wine made from purple yam and lotus root according to claim 6, characterized in that, In step (6), the temperature of the sealed anaerobic fermentation is 22-24℃; the lees are separated by plate and frame filtration, and the filtration pressure is 0.2-0.5MPa; the inner wall of the aging vat is coated with nano titanium dioxide; the aging temperature is 18-22℃, and the aging time is 28-32 days.

10. A method for brewing purple yam and lotus root fermented wine according to claim 6, characterized in that, In step (7), the multi-tank series low-temperature clarification process adopts a five-stage series container tank clarification system based on the principle of connected pressure: First, the wine juice obtained by manual physical pressing after fermentation is mixed with the reserved primary fermentation product and pumped into the clarification tank for preliminary filtration. Then, the wine juice is continuously passed through five series-connected container tanks under the action of system pressure difference. Impurities are removed through staged low-temperature sedimentation and physical filtration to obtain clear wine.