Four-gradient non-added sucrose raspberry health-care fermentation wine and controllable preparation method thereof

Abstract

The application discloses a four-gradient non-added sucrose raspberry health-care fermentation wine for preventing disease and a controllable preparation method thereof, and belongs to the technical field of brewing of medicine-food homologous compound fermentation wine. The fermentation wine takes raspberry as a main fermentation raw material, takes natural honey and / or large yellow rice saccharification liquid as a natural fermentation carbon source, does not add white granulated sugar, cane sugar syrup and glucose-fructose syrup, constructs a raspberry honey pure fruit fermentation system, a raspberry large yellow rice gradient saccharification co-fermentation system and a raspberry large yellow rice honey three-in-one co-fermentation system. According to the method, the saccharification time length, the saccharification rate and the fermentation termination timing of the large yellow rice are controlled, so that each set of system can form dry type, semi-dry type, semi-sweet type and sweet type four-grade wine bodies according to GB / T 15038-2020, and the controllable grading of the sweetness, the alcohol content and the residual sugar of the raspberry fermentation wine is realized.

Description

Technical Field

[0001] This invention belongs to the field of medicinal and edible compound fermented wine brewing technology, specifically referring to a four-gradient sugar-free raspberry health-preserving fermented wine and its controllable preparation method. Background Technology

[0002] Raspberries, also known as mahogany, are a type of berry used in both food and medicine. The fruit contains organic acids, anthocyanins, flavonoids, polyphenols, amino acids, vitamins, and minerals, possessing a distinctive fruity aroma and a sweet and sour flavor, making it suitable for developing fruit wines, vinegars, drinks, and fermented foods. Using raspberries to prepare low-alcohol fermented wines can retain some of the fruit's aroma, color, and active ingredients, creating products that combine drinking and health-promoting attributes.

[0003] However, raspberries have a relatively limited natural sugar content, with fresh raspberries typically having a natural sugar content of around 8–11° Brix. Fermentation relying solely on the raspberry's own sugars theoretically results in a low alcohol content, a wine that is prone to being acidic and thin, and makes it difficult to consistently obtain fruit wine products with varying sweetness levels. Current fruit wine production processes often use exogenous refined sugar sources such as white sugar, sucrose syrup, and fructose syrup to increase the sugar content of the fermentation substrate or adjust the sweetness of the finished product. While this method is simple to implement, it suffers from problems such as high levels of exogenous sucrose added, flavors easily masked by the sugar taste, difficulty in controlling fusel alcohols and off-flavors, and difficulty in meeting contemporary consumer demands for less added sugar and healthier products.

[0004] On the other hand, some health-preserving wines on the market are blended wines made by soaking medicinal herbs in baijiu or huangjiu, rather than being obtained through in-situ co-fermentation of the raw materials themselves. This results in insufficient retention of the active ingredients and fermentation aromas of the raw materials, making it difficult to showcase the complex flavors created by the co-fermentation of raspberries, grains, and honey. Furthermore, consumer preferences differ among general drinkers, women, seasoned drinkers, and health-conscious consumers regarding sweetness, alcohol content, acidity, and flavor richness. A single sweetness level or a single fermentation system is insufficient to cater to diverse consumption scenarios.

[0005] Millet contains starch and grain aroma components. After saccharification, it can produce fermentable sugars such as glucose, which can impart grain body and traditional fermented wine flavor to the wine. Naturally ripened honey contains glucose and fructose. Yeast can directly utilize some of the monosaccharides in it, and the fermentation rate of fructose is relatively slow, which is suitable for the formation of natural residual sugar during fermentation. If the raw fructose of raspberries, saccharified glucose from millet, and monosaccharides from natural honey can be combined as natural carbon sources, and the residual sugar in the finished product can be controlled by the degree of saccharification and the timing of fermentation termination, it is possible to prepare four grades of raspberry fermented wine—dry, semi-dry, semi-sweet, and sweet—without adding white sugar, sucrose syrup, or fructose syrup.

[0006] Therefore, it is necessary to provide a four-gradient, sugar-free raspberry health-preserving fermented wine and its controllable preparation method, so that raspberries, millet, and natural honey can form a replicable fermentation system under the framework of natural carbon sources, and achieve the unification of sweetness grading, alcohol control, acidity control, and process stability. Summary of the Invention

[0007] In response to the above situation and to overcome the shortcomings of the prior art, this invention provides a four-gradient, additive-free, sucrose-based fermented raspberry wine for disease prevention and health preservation, and its controllable preparation method, to solve the problems of traditional raspberry wine having low natural sugar content, relying on exogenous sucrose for sugar supplementation, easily becoming sour and thin, having an incomplete sweetness system, and insufficient health-preserving fermentation properties.

[0008] To achieve the above objectives, this invention provides a four-gradient, additive-free, sucrose-based fermented wine for disease prevention and health maintenance. The fermented wine uses raspberries as the main fermentation ingredient and natural honey and / or millet saccharification liquid as the natural fermentation carbon source. No white sugar, sucrose syrup, fructose syrup, artificial flavorings, synthetic pigments, or food preservatives are added throughout the entire process. The fermented wine includes one or more of the following: a raspberry-honey pure fruit fermentation system, a raspberry-millet gradient saccharification co-fermentation system, and a raspberry-millet-honey three-in-one co-fermentation system. Each fermentation system can be prepared into four sweetness levels—dry, semi-dry, semi-sweet, and sweet—according to GB / T 15038-2020.

[0009] Furthermore, "no added sucrose" means that no sugar supplements, such as granulated sugar, powdered sugar, rock sugar, sucrose syrup, fructose syrup, etc., which are mainly refined sucrose or artificially refined sugar sources, are added during the pre-fermentation, fermentation, and post-fermentation blending stages. However, it does not exclude the presence of natural sugars from raspberries, sugars produced by the saccharification of millet, and monosaccharides inherent in naturally ripened honey as carbon sources for fermentation.

[0010] Furthermore, the four sweetness levels are classified according to the GB / T 15038-2020 fruit wine standard: the total sugar content of dry wine (calculated as glucose) is no more than 4.0 g / L, the total sugar content of semi-dry wine (calculated as glucose) is 4.1–12.0 g / L, the total sugar content of semi-sweet wine (calculated as glucose) is 12.1–45.0 g / L, and the total sugar content of sweet wine (calculated as glucose) is 45.1–90.0 g / L.

[0011] Preferably, the physicochemical properties of the fermented wine include an alcohol content of 10.5–12.5% ​​vol, total acidity (calculated as tartaric acid) of 4.0–7.0 g / L, volatile acidity (calculated as acetic acid) of no more than 1.2 g / L, and dry extract of no less than 20.0 g / L. These properties are used to ensure that the wine has suitable alcohol content, acidity, extract, and stability, avoiding problems such as low alcohol content and weak acidity, excessive volatile acidity, or insufficient extract.

[0012] Furthermore, the present invention also provides a controllable preparation method for a four-gradient, additive-free, sucrose-based fermented wine for disease prevention and health maintenance, comprising the following steps:

[0013] S1. Raw material selection: Select ripe raspberries, millet and natural ripe honey as raw materials;

[0014] S2. Raw material pretreatment: sorting, cleaning, crushing and color protection of raspberries; cleaning, soaking, steaming and cooling of millet.

[0015] S3, formulated with natural carbon sources, selects raspberry honey pure fruit fermentation, raspberry millet gradient saccharification co-fermentation or raspberry millet honey three-in-one co-fermentation according to the target fermentation system, without adding white sugar, sucrose syrup or fructose syrup;

[0016] S4. Gradient saccharification of millet is carried out to obtain saccharified materials with different saccharification rates;

[0017] S5. Mix the raspberry material with natural honey and / or saccharified millet material in the same tank for inoculation and fermentation;

[0018] S6. Control the timing of fermentation termination according to the target sweetness level, so that the wine can be dry, semi-dry, semi-sweet or sweet respectively;

[0019] S7. The fermented wine undergoes low-temperature aging, desliming, low-temperature pasteurization, precision filtration, and aseptic filling.

[0020] Furthermore, in the raspberry honey pure fruit fermentation system, naturally ripened honey completely replaces white sugar as a supplementary carbon source. Raspberries provide fruity aromas, organic acids, anthocyanins, and native fructose, while honey provides glucose, fructose, and honey aromas. This system utilizes the relatively slow fermentation rate of fructose in honey, forming natural residual sugars at the end of fermentation, allowing the wine to retain the pure fresh fruit honey style.

[0021] Furthermore, in the raspberry-millet gradient saccharification co-fermentation system, the mass ratio of fresh raspberries to dried millet is 3.0–4.0:1; preferably, the mass ratio is 3.5:1. After soaking, steaming, and saccharification, the millet releases fermentable sugars such as glucose, which, together with the fructose from the raspberries, serve as a carbon source. This system achieves four levels of sweetness without adding honey or white sugar by controlling the saccharification time and rate of the millet to create different initial levels of fermentable sugars.

[0022] Furthermore, in the raspberry, millet, and honey three-in-one co-fermentation system, raspberries, millet saccharified materials, and naturally ripened honey ferment together. Raspberries provide acidity, color, and fruity aroma; millet provides saccharified sugars and a mellow taste; and honey provides monosaccharides and a honey aroma. This system forms a triple natural carbon source complex of raspberry fructose, millet saccharified glucose, and honey monosaccharides, suitable for preparing high-end health-promoting fermented wines with richer flavor layers.

[0023] Preferably, the gradient saccharification of millet uses the saccharification depth of millet starch as the control target; specifically, the saccharification rate for dry liquor is 78%–85%, with a saccharification time of 17–19 h; for semi-dry liquor, it is 72%–78%, with a saccharification time of 14–16 h; for semi-sweet liquor, it is 65%–72%, with a saccharification time of 11–13 h; and for sweet liquor, it is 58%–65%, with a saccharification time of 9–10 h. Through this gradient, the dry liquor achieves a more complete release of fermentable sugars and a deeper degree of fermentation, while the sweet liquor develops its sweetness through shallower saccharification, earlier termination, and retention of residual sugar.

[0024] Preferably, the timing of termination is determined by real-time monitoring of total sugar, alcohol content, and titratable acidity during fermentation. When the wine reaches the total sugar range corresponding to the target sweetness level and the alcohol content reaches 10.5–12.5% ​​vol, fermentation is terminated or inhibited by at least one of the following methods: cooling, racking to remove sludge, and low-temperature pasteurization. Further, the low-temperature aging temperature is 0–8°C, the low-temperature aging time is 15–90 days, the low-temperature pasteurization temperature is 62–68°C, and the holding time is 15–30 minutes.

[0025] Preferably, a four-gradient process control table is established for the wine. This process control table records at least the target sweetness level, target total sugar range, saccharification rate of millet, saccharification time, total sugar at fermentation termination, alcohol at fermentation termination, total acid, volatile acid, dry extract, and post-aging conditions. Using this process control table, different batches can be adjusted based on the sugar content of the raspberries, the sugar content of the honey, and the saccharification state of the millet, ensuring the product consistently meets the four sweetness levels.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] 1. The entire process abandons white sugar, sucrose syrup and fructose syrup, and instead uses raspberry raw fructose, saccharified glucose from millet and natural honey monosaccharides as natural fermentation carbon sources, which is in line with the consumption trend of no added sucrose and less refined sugar;

[0028] 2. Through the raspberry honey pure fruit fermentation system, the raspberry millet gradient saccharification co-fermentation system, and the raspberry millet honey three-in-one co-fermentation system, the product positioning covers three categories: pure fruit honey brewing, traditional fruit and grain co-fermentation, and high-end compound health fermented wine.

[0029] 3. By controlling the saccharification time, saccharification rate and fermentation termination time of millet, four sweetness grades of dry, semi-dry, semi-sweet and sweet are achieved, filling the gap in the four-gradient system of sugar-free raspberry fermented wine.

[0030] 4. By controlling the alcohol content, total acidity, volatile acidity, and dry extract, the risk of the wine being too acidic, too thin, having too much fusel alcohol, and having poor stability can be reduced.

[0031] 5. Raspberries and millet are co-fermented to create a complex nutritional system and unique flavor profile:

[0032] (1) Nutritional complementarity: Raspberries are rich in berry-characteristic nutrients such as anthocyanins, organic acids, and vitamin C, while millet is rich in grain nutrients such as starch, protein, and B vitamins. After co-fermentation, the two form a complementary nutritional system, which makes up for the lack of nutritional spectrum of single raw materials.

[0033] (2) Unique flavor: Raspberries contribute a distinct berry aroma and acidity, while millet produces a grain aroma and fullness after saccharification and fermentation. The fusion of fruit and grain creates a unique flavor profile that is distinct from single fruit wines or single grain wines.

[0034] (3) Synergistic effect: During the co-fermentation of fruits and grains, the organic acids of raspberries promote the gelatinization and saccharification of millet starch, and the saccharified liquid of millet buffers the high acidity of raspberries, forming a synergistic optimization of the fermentation environment and producing a metabolite spectrum that is not available in single-raw-material fermentation. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating the controllable preparation method of the four-gradient sugar-free raspberry health-preserving fermented wine of the present invention.

[0036] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] Raspberry Honey Pure Dried Fruit Fermented Wine

[0040] Select 100 kg of ripe raspberries, remove moldy, worm-eaten, and unripe fruit, wash and drain them, then crush them to obtain raspberry pulp. Select 8 kg of natural, ripe honey. The honey is not boiled at high temperatures, but only dissolved in warm water and filtered before use. No white sugar, sucrose syrup, fructose syrup, artificial flavors, synthetic colors, or food preservatives are added throughout the entire process.

[0041] Raspberry pulp and honey were mixed, and the soluble solids content of the initial fermentation broth was adjusted to suit yeast fermentation. Fruit wine yeast was inoculated, and fermentation was carried out at 18–24°C. Total sugar, alcohol content, and total acid were measured during fermentation. When the alcohol content reached 10.5–12.5% ​​vol and the total sugar (calculated as glucose) did not exceed 4.0 g / L, the temperature was lowered to 0–8°C, and the container was racked to remove sludge. Subsequently, low-temperature aging, pasteurization, precision filtration, and aseptic bottling were performed to obtain a pure raspberry honey dried fruit fermented wine.

[0042] This wine does not rely on external sucrose for sugar supplementation. The fermentation carbon source comes from the native fructose of raspberries and the inherent monosaccharides of honey. The fruit and honey aromas are well-balanced, and the total sugar content meets the requirements for dry fruit wine.

[0043] Example 2

[0044] Raspberry Honey Pure Fruit Sweet Fermented Wine

[0045] Compared to Example 1, this example increases the amount of naturally ripened honey added and performs cooling, racking to remove mud, and low-temperature pasteurization earlier after fermentation reaches the target alcohol content, thus retaining a higher level of natural residual sugar in the wine. At the end of fermentation, the total sugar (calculated as glucose) is controlled at 45.1–90.0 g / L, the alcohol content is controlled at 10.5–12.5% ​​vol, and the total acid (calculated as tartaric acid) is controlled at 4.0–7.0 g / L, yielding a pure fruit-sweet raspberry honey fermented wine.

[0046] This system utilizes the relatively slow fermentation rate of fructose in honey to retain its sweetness, avoiding the need to add white sugar later to create a sweet taste.

[0047] Example 3

[0048] Raspberry and millet gradient saccharification co-fermentation dry fermented wine

[0049] 105 kg of ripe raspberries and 30 kg of dried millet were selected, with a fresh raspberry to dried millet mass ratio of 3.5:1. The raspberries were sorted, washed, and crushed before use. The millet was washed, soaked, steamed, and cooled, then saccharified with a saccharifying agent for 18 hours to obtain deeply saccharified millet material. After saccharification, the saccharified millet material was filtered, and the reducing sugar content of the filtrate was measured and recorded as part of the saccharification process. Simultaneously, the residual starch content in the saccharified material was measured, and the saccharification rate was calculated by converting the total starch content of the millet before saccharification to the residual starch content after saccharification. The conversion formula is as follows:

[0050] Saccharification rate = (Total starch content before saccharification - Residual starch content after saccharification) / Total starch content before saccharification × 100%.

[0051] In this embodiment, the saccharification rate of millet is approximately 82%.

[0052] Raspberry pulp and deeply saccharified millet were mixed and co-fermented in a fermentation tank with fruit wine yeast. During fermentation, the raw fructose from the raspberries and the glucose produced from the saccharification of the millet were both utilized by the yeast. When the alcohol content reached 10.5–12.5% ​​vol and the total sugar was no more than 4.0 g / L, the fermentation process was terminated at low temperature, racked to remove sludge, aged at low temperature, pasteurized at low temperature, finely filtered, and aseptically bottled to obtain a dry fermented wine made from raspberry and millet with graded saccharification and co-fermentation.

[0053] This wine, co-fermented with raspberries and millet, possesses both the fruity aroma of raspberries and the grain aroma of millet. The anthocyanin content from the raspberries is retained at 75%–85%, while the B vitamins produced during millet fermentation are 30%–50% higher than those from raspberry-only fermentation, resulting in a complex nutritional profile of fruit and grain fusion. Sensory evaluation shows that the flavor harmony and complexity of this co-fermented wine are superior to both single-raspberry fermentation wines and raspberry wines with added white sugar.

[0054] The raspberry and millet gradient saccharification co-fermentation dry fermented wine obtained in this embodiment was tested. The test methods and results are described below.

[0055] Example 4

[0056] Raspberry and millet gradient saccharification co-fermentation semi-dry fermented wine

[0057] Compared with Example 3, this example controls the saccharification time of millet to 15 hours, with a saccharification rate of approximately 75%. At the end of fermentation, the total sugar content (calculated as glucose) is controlled at 4.1–12.0 g / L, and the alcohol content is controlled at 10.5–12.5% ​​vol, resulting in a semi-dry fermented wine made from raspberry and millet through gradient saccharification and co-fermentation.

[0058] Compared to dry wines, this wine retains a small amount of residual sugar, resulting in a smoother balance of sweet and sour, making it suitable for general drinking occasions.

[0059] Example 5

[0060] Raspberry and millet gradient saccharification co-fermentation semi-sweet fermented wine

[0061] Compared to Example 3, this example controls the saccharification time of millet to 12 hours, with a saccharification rate of approximately 68%. Total sugar and alcohol content are monitored in real time during fermentation. When the total sugar (calculated as glucose) reaches 12.1–45.0 g / L and the alcohol content reaches 10.5–12.5% ​​vol, cooling, desludge removal, and sterilization are performed to obtain a semi-sweet fermented wine made from raspberry and millet through gradient saccharification and co-fermentation.

[0062] This wine has a distinct fruit and grain aroma and a mellow sweetness, making it suitable for female consumers and those consuming low-alcohol, sweet fruit wines.

[0063] Example 6

[0064] Raspberry and millet gradient saccharification co-fermentation sweet fermented wine

[0065] Compared to Example 3, this example controls the saccharification time of millet to 9–10 hours, achieving a saccharification rate of approximately 60%, and retains more natural residual sugar by terminating fermentation earlier. At the end of fermentation, the total sugar content (calculated as glucose) is 45.1–90.0 g / L, and the alcohol content is 10.5–12.5% ​​vol, yielding a sweet fermented wine made from raspberry and millet through gradient saccharification and co-fermentation.

[0066] This wine contains no added white sugar; its sweet flavor is achieved through the light saccharification of millet, the use of raspberry fructose, and controlled fermentation termination.

[0067] Example 7

[0068] Raspberry, millet, and honey three-in-one fermented wine

[0069] Add 15-18 kg of natural mature honey to raspberry pulp and glutinous millet saccharification materials, control the saccharification rate of glutinous millet to 58%-65%, and retain natural residual sugar by terminating fermentation early, so that the total sugar of the finished product is 45.1-90.0 g / L (calculated as glucose) and the alcohol content is 10.5-12.5% ​​vol, to obtain sweet three-in-one co-fermented wine.

[0070] In this embodiment, raspberries provide fruity aroma, acidity, and color; millet provides saccharified glucose and grain richness; and honey provides honey aroma and monosaccharides. By corresponding the amount of honey added, the saccharification rate of millet, and the timing of fermentation termination with the sweetness level, the three-in-one co-fermentation system can stably form four levels of wine body: dry, semi-dry, semi-sweet, and sweet.

[0071] Comparative Example 1

[0072] Raspberry wine with added white sugar for added sweetness

[0073] This comparative example uses raspberries as the raw material, with added white sugar before fermentation to supplement the sugar content. Although this can increase the sugar content of the fermentation substrate, the source of the sweetness in the wine is inconsistent with the natural carbon source, and it does not conform to the positioning of a product without added sucrose.

[0074] Comparative Example 2

[0075] Raspberry and millet fermented wine without graded saccharification control of millet

[0076] This comparative example involves the fermentation of raspberries and millet, but it does not differentiate between saccharification time and saccharification rate. Due to the unstable release of fermentable sugars, the total sugar and alcohol content fluctuate significantly between different batches, making it difficult to consistently produce four grades of products: dry, semi-dry, semi-sweet, and sweet.

[0077] Comparative Example 3

[0078] Simple raspberry self-fermented wine

[0079] This comparative recipe uses only raspberries for fermentation, without adding millet saccharification materials or naturally ripened honey. Due to the limited natural sugar content of raspberries, the alcohol content is relatively low, and the body is relatively acidic and thin, making it difficult to simultaneously meet the requirements of 10.5-12.5% ​​vol alcohol content and four levels of sweetness classification.

[0080] Detection methods

[0081] 1. Saccharification rate test of millet: Take millet material before saccharification and millet material after saccharification, and measure the total starch content and residual starch content respectively. Calculate the saccharification rate according to the formula: Saccharification rate = (Total starch content before saccharification - Residual starch content after saccharification) / Total starch content before saccharification × 100%; At the same time, filter the saccharified millet material after saccharification, measure the reducing sugar content of the filtrate and record it as part of the saccharification process.

[0082] 2. Saccharification time recording: Start timing from when the saccharifying agent is added and the saccharification temperature is reached, and stop timing when saccharification is terminated, and record the saccharification time.

[0083] 3. Total sugar test: Tested according to the relevant methods of GB / T 15038-2020 for fruit wine, and the dry, semi-dry, semi-sweet and sweet types were determined by glucose meter.

[0084] 4. Alcohol content test: The alcohol content is tested at 20℃, and the unit is %vol.

[0085] 5. Total acidity detection: Calculated as tartaric acid, the control range is 4.0~7.0 g / L.

[0086] 6. Volatile acid detection: Calculated as acetic acid, the concentration should not exceed 1.2 g / L.

[0087] 7. Dry extractives test: control not less than 20.0 g / L.

[0088] The test results are as follows:

[0089] Testing items Test results Control requirements saccharification rate of millet 82% 78%～85% Glycation time 18 h 17～19 h Total sugar (as glucose) 3.2 g / L ≤4.0 g / L Alcohol content (20℃) 11.6% vol 10.5~12.5%vol Total acidity (calculated as tartaric acid) 5.4 g / L 4.0~7.0 g / L Volatile acids (calculated as acetic acid) 0.46 g / L ≤1.2 g / L Dry extract 24.8 g / L ≥20.0 g / L

[0090] The test results show that the saccharification rate and saccharification time of millet in this embodiment meet the deep saccharification requirements corresponding to dry wine. The total sugar, alcohol content, total acid, volatile acid and dry extract of the final fermented wine all fall within the range set by this invention, and the total sugar meets the requirements of dry fruit wine.

[0091] 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 variations 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 four-gradient, additive-free, raspberry fermented wine for disease prevention and health maintenance, characterized in that: The fermented wine uses raspberries as the main fermentation raw material. The natural fermentation carbon source includes raspberry native sugar, natural mature honey's inherent monosaccharides, and / or sugars produced by saccharification of millet. The fermented wine includes one or more of the following: a raspberry honey pure fruit fermentation system, a raspberry millet gradient saccharification co-fermentation system, and a raspberry millet honey three-in-one co-fermentation system. The raspberry millet gradient saccharification co-fermentation system and the raspberry millet honey three-in-one co-fermentation system form complex nutrition and unique flavor through fruit and grain co-fermentation. Each fermentation system can be prepared into four sweetness levels of wine: dry, semi-dry, semi-sweet, and sweet, according to GB / T 15038-2020.

2. The four-gradient sugar-free raspberry health-preserving fermented wine according to claim 1, characterized in that: The raspberry honey pure fruit fermentation system uses raspberry fructose and monosaccharides from natural ripe honey as fermentation carbon sources, and utilizes the characteristic that the fermentation rate of fructose in natural ripe honey is lower than that of glucose to retain residual sugar in the wine.

3. The four-gradient sugar-free raspberry health-preserving fermented wine according to claim 1, characterized in that: In the raspberry-millet gradient saccharification co-fermentation system, the mass ratio of fresh raspberries to dried millet is 3.0–4.0:1, preferably 3.5:1, and the fermentation carbon source is provided by glucose produced from the saccharification of millet starch and raw fructose from raspberries.

4. The four-gradient sugar-free raspberry health-preserving fermented wine according to claim 1, characterized in that: The raspberry, millet, and honey three-in-one co-fermentation system contains raspberry fructose, glucose produced by millet saccharification, and fructose and glucose from naturally matured honey, serving as a complex natural fermentation carbon source.

5. The four-gradient sugar-free raspberry health-preserving fermented wine according to claim 1, characterized in that: No white sugar, sucrose syrup, or fructose syrup are added to the fermented wine before, during, or after fermentation, and no artificial flavorings, synthetic colorings, or food preservatives are added.

6. The four-gradient sugar-free raspberry health-preserving fermented wine according to claim 1, characterized in that: The total sugar content of the dry wine (calculated as glucose) is no more than 4.0 g / L; the total sugar content of the semi-dry wine (calculated as glucose) is 4.1–12.0 g / L; the total sugar content of the semi-sweet wine (calculated as glucose) is 12.1–45.0 g / L; the total sugar content of the sweet wine (calculated as glucose) is 45.1–90.0 g / L; the alcohol content of the fermented wine is 10.5–12.5% ​​vol; the total acid content (calculated as tartaric acid) is 4.0–7.0 g / L; the volatile acid content (calculated as acetic acid) is no more than 1.2 g / L; and the dry extract content is no less than 20.0 g / L.

7. A controllable preparation method for a four-gradient, sugar-free raspberry health-promoting fermented wine, characterized in that: The method for preparing the fermented wine according to any one of claims 1 to 6 comprises the following steps: S1. Raw material selection: Select ripe raspberries, millet and natural ripe honey as raw materials; S2. Raw material pretreatment: sorting, cleaning, crushing and color protection of raspberries; cleaning, soaking, steaming and cooling of millet. S3, Natural carbon source formulation, select raspberry honey pure fruit fermentation, raspberry millet gradient saccharification co-fermentation or raspberry millet honey three-in-one co-fermentation according to the target fermentation system; S4. Gradient saccharification of millet is carried out to obtain saccharified materials with different saccharification rates; S5. Mix the raspberry material with natural honey and / or saccharified millet material in the same tank for inoculation and fermentation; S6. Control the timing of fermentation termination according to the target sweetness level, so that the wine can be dry, semi-dry, semi-sweet or sweet respectively; S7. The fermented wine undergoes low-temperature aging, desliming, low-temperature pasteurization, precision filtration, and aseptic filling.

8. The controllable preparation method according to claim 7, characterized in that: In step S4, gradient saccharification uses the saccharification depth of millet starch as the control object. The saccharification rate for dry liquor is 78%–85% and the saccharification time is 17–19 h; the saccharification rate for semi-dry liquor is 72%–78% and the saccharification time is 14–16 h; the saccharification rate for semi-sweet liquor is 65%–72% and the saccharification time is 11–13 h; and the saccharification rate for sweet liquor is 58%–65% and the saccharification time is 9–10 h.

9. The controllable preparation method according to claim 7, characterized in that: In step S5, in the raspberry honey pure fruit fermentation system, natural mature honey completely replaces white sugar as a supplementary carbon source. In the raspberry millet gradient saccharification co-fermentation system, the mass ratio of fresh raspberries to dried millet is 3.5:

1. The raspberry millet honey three-in-one co-fermentation system uses raspberries, millet saccharification materials and natural mature honey for co-fermentation.

10. The controllable preparation method according to claim 7, characterized in that: In step S6, the timing of fermentation termination is determined by real-time monitoring of total sugar, alcohol content, and titratable acidity in the fermentation broth. When the wine reaches the total sugar range corresponding to the target sweetness level and the alcohol content reaches 10.5–12.5% ​​vol, fermentation is terminated or inhibited by at least one of the following methods: cooling, mud removal, and sterilization. In step S7, the low-temperature post-aging temperature is 0–8℃, the low-temperature post-aging time is 15–90 days, the pasteurization temperature is 62–68℃, and the holding time is 15–30 minutes. A process control table for four-gradient wines is established. The process control table records at least the target sweetness level, target total sugar range, saccharification rate of millet, saccharification time, total sugar at fermentation termination, alcohol content at fermentation termination, and post-aging conditions.

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