Fungus fermentation polysaccharide as well as preparation method and application thereof

Abstract

The invention relates to the technical field of food processing, in particular to fungus fermentation polysaccharide as well as a preparation method and application thereof. The fungus fermentation polysaccharide provided by the invention can improve the anti-freezing performance of the frozen green steamed stuffed bun, and meanwhile, the fungus fermentation polysaccharide is combined with gluten to maintain the stability of a dough structure, so that the steamed quality of the frozen green steamed stuffed bun is remarkably improved. The fungus fermentation polysaccharide provided by the invention can reduce the water loss of the frozen green steamed stuffed bun in the freezing storage process and enhance the elasticity and plumpness of the skin layer of the frozen green steamed stuffed bun, so that the steamed stuffed bun not only recovers the original volume and elasticity, but also has better taste and appearance. The fungus fermentation polysaccharide provided by the invention has good water-retaining property and freezing resistance, and can endow frozen green steamed stuffed buns with excellent frozen storage stability and after-steaming restorability.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a fungal fermentation polysaccharide, its preparation method, and its application. Background Technology

[0002] Steamed buns, a traditional Chinese fermented food, are now produced and sold as frozen foods. Frozen raw steamed buns stored below -20 degrees Celsius often face problems such as moisture migration, ice crystals damaging the dough structure, collapse after steaming, and poor texture and elasticity. This is due to the unique properties of frozen raw steamed buns, such as the high moisture content of the dough, the humidity of the filling, and the expansion of the skin during steaming.

[0003] Currently, the main methods to improve the frozen storage quality of raw steamed buns are to add emulsifiers or water-retaining agents, but the improvement effect is limited and cannot effectively solve the above problems. In addition, the product labels are not clean enough. Summary of the Invention

[0004] In view of this, the present invention provides a fungal fermentation polysaccharide, its preparation method and application. The fungal fermentation polysaccharide provided by the present invention can effectively improve the frozen storage quality of frozen raw buns.

[0005] This invention provides a method for preparing fungal fermented polysaccharides, comprising the following steps: The fungal liquid deep fermentation broth was subjected to precipitation, alcohol washing, and freeze-drying in sequence to obtain the fungal fermentation polysaccharide.

[0006] Preferably, the fungal liquid deep fermentation broth is prepared using food-grade fungal fruiting bodies, including shiitake mushrooms (Vigna angularis). Lentinula edodes ), Ganoderma lucidum ( Ganoderma lucidum ), Grifola frondosa ( Grifola frondosa ), white fungus ( Tremella fuciformis ), Hericium erinaceus ( Hericium erinaceus ) and wood ear fungus ( Auricularia auricula-judae One or more of them.

[0007] Preferably, the freeze-drying temperature is -20 °C and the freeze-drying time is 24 to 120 hours.

[0008] The present invention also provides fungal fermentation polysaccharides obtained by the preparation method described above, including dextran, mannan, heteropolysaccharides or glycopeptides.

[0009] Preferably, the molecular weight of the fungal fermentation polysaccharide is 10~2000 kDa.

[0010] The present invention also provides the application of the fungal fermented polysaccharide described above in frozen raw steamed buns.

[0011] The present invention also provides a frozen raw bun, which is prepared from the following raw materials in parts by weight: 100 parts flour, 46-50 parts water, 0.5-4 parts yeast, 2-10 parts sugar and 0.05-10 parts fungal fermentation polysaccharide; wherein the fungal fermentation polysaccharide is the fungal fermentation polysaccharide described in the above scheme.

[0012] The present invention also provides a method for preparing the frozen raw buns described above, comprising the following steps: Flour, water, yeast, sugar, and fungal fermentation polysaccharide are mixed and then shaped, proofed, quick-frozen, and frozen to obtain the frozen raw buns; the fungal fermentation polysaccharide is the fungal fermentation polysaccharide described in the above scheme.

[0013] The present invention also provides a steamed bun, which is obtained by steaming frozen raw steamed buns; the frozen raw steamed buns are the frozen raw steamed buns described in the above scheme or the frozen raw steamed buns obtained by the preparation method described in the above scheme.

[0014] The present invention also provides a method for preparing the steamed buns described above, comprising the following steps: Frozen raw buns are steamed to obtain buns; the frozen raw buns are the frozen raw buns described in the above scheme or the frozen raw buns obtained by the preparation method described in the above scheme.

[0015] This invention provides a method for preparing fungal fermented polysaccharides. The fungal fermented polysaccharides prepared by this invention can improve the freeze resistance of frozen raw buns, while also binding with gluten to maintain the stability of the dough structure, significantly improving the post-steaming quality of frozen raw buns. The fungal fermented polysaccharides prepared by this invention can reduce moisture loss from frozen raw buns during freezing, enhance the elasticity and fullness of the frozen bun skin, so that the steamed buns not only regain their original volume and elasticity but also have better taste and appearance. The fungal fermented polysaccharides provided by this invention have good water retention and freeze resistance, endowing frozen raw buns with excellent freeze-drying stability and post-steaming recovery.

[0016] The preparation method provided by this invention is highly flexible and applicable to various fungal polysaccharides, such as those from shiitake mushrooms, tremella, or reishi mushrooms. It is also suitable for various flour formulations and different types of steamed buns, such as sweet buns, vegetable buns, or meat buns. The preparation method provided by this invention has good process compatibility, can meet the production needs of different food companies, and has broad industrial application prospects.

[0017] This invention also provides fungal fermentation polysaccharides obtained by the preparation method described above. The fungal fermentation polysaccharides provided by this invention achieve the following beneficial effects: 1) Naturally Sourced and Safe for Consumption: The fungal fermentation polysaccharides provided in this invention are all derived from the deep liquid fermentation of edible fungi. They possess the advantages of being natural, safe, and free of chemically synthesized ingredients, meeting consumers' demand for clean-label foods. Compared to traditional synthetic additives, fungal fermentation polysaccharides, as natural food ingredients, align with modern consumers' preferences for healthy and natural foods. Compared to traditional chemical additives (such as preservatives or elasticizers), fungal fermentation polysaccharides are not only more natural and safer but also sustainable, effectively improving the quality of frozen raw buns while reducing the amount of food additives used.

[0018] 2) Significantly Improved Frozen Storage Performance: Adding fungal fermented polysaccharides to frozen raw steamed buns effectively inhibits moisture migration and ice crystal formation, reducing damage to the dough structure during freezing and thus maintaining good frozen storage stability. This innovation ensures the stability of the gluten network after thawing and steaming, effectively preventing common problems such as bun collapse and rough surface, significantly improving the frozen storage quality of raw steamed buns. It is not only suitable for industrial frozen food production but also particularly beneficial for meeting consumer demand for natural, chemical-free foods, demonstrating promising application prospects.

[0019] 3) Stable structure and good elasticity after steaming: Frozen raw buns, even after freezing and steaming, retain good specific volume and elasticity. They exhibit strong recovery after steaming, with a taste close to fresh buns. They maintain high expansion after steaming, avoiding the quality problems of traditional frozen raw buns such as dryness, hardening, and collapse after steaming. Consumers can enjoy a taste and quality close to freshly made buns.

[0020] This invention also provides the application of the fungal fermentation polysaccharide described above in frozen raw steamed buns. This invention solves the quality deterioration problem of frozen raw steamed buns during frozen storage by using fungal fermentation polysaccharide, particularly addressing the issues of poor elasticity, dough cracking, post-steaming collapse, and dry texture after steaming. The fungal fermentation polysaccharide provided by this invention is suitable for frozen raw steamed buns stored at -18 ℃ or below. Even after being frozen and stored below 0 degrees Celsius for more than 90 days, the frozen raw steamed buns still maintain their structural integrity, good elasticity, and minimal collapse after steaming.

[0021] This invention also provides a frozen raw steamed bun. The frozen raw steamed bun provided by this invention, by adding the fungal fermentation polysaccharide described above, ensures that it can restore its original volume, elasticity and texture after steaming, making the bun structurally intact, elastic, and with strong recovery after steaming, close to the quality of fresh steamed buns.

[0022] This invention also provides a method for preparing the frozen raw buns described in the above-mentioned scheme. The preparation method provided by this invention is easy to operate, does not rely on large-scale equipment, has low cost, and has broad application prospects.

[0023] This invention also provides a steamed bun. The steamed bun provided by this invention is prepared using the frozen raw steamed bun method described above. This invention, by adding fungal fermentation polysaccharides to the frozen raw steamed bun, inhibits ice crystal formation, improves the damage of ice crystals to yeast, gluten protein, and starch granules during freezing, and enhances the structural stability of the frozen raw steamed bun during freezing, thus significantly improving the fullness and texture of the steamed bun of this invention.

[0024] This invention also provides a method for preparing the steamed buns described in the above-mentioned scheme. The preparation method provided by this invention is highly efficient, natural and pollution-free, and can meet people's needs for quick consumption. Detailed Implementation

[0025] This invention provides a method for preparing fungal fermented polysaccharides, comprising the following steps: The fungal liquid deep fermentation broth was subjected to precipitation, alcohol washing, and freeze-drying in sequence to obtain the fungal fermentation polysaccharide.

[0026] In this invention, the method for preparing the fungal liquid deep fermentation broth preferably includes the following steps: selecting food-grade fungal fruiting bodies, expanding their cultivation on a solid plate culture medium, inoculating them into a seed culture medium, and then transferring them to a liquid deep fermentation culture medium for liquid deep fermentation.

[0027] In this invention, the food-grade fungal fruiting bodies are preferably washed before use; the food-grade fungal fruiting bodies preferably include shiitake mushrooms (…). Lentinula edodes ), Ganoderma lucidum ( Ganoderma lucidum ), Grifola frondosa ( Grifola frondosa ), white fungus ( Tremella fuciformis ), Hericium erinaceus ( Hericium erinaceus ) and wood ear fungus ( Auricularia auricula-judae One or more of them.

[0028] In this invention, the expanded culture preferably includes the following steps: under aseptic conditions, inoculating 1 cm 3 Food-grade fungal fruiting bodies of various sizes are placed on solid agar plates and cultured at 20-30 ℃ for 3-10 days to obtain fungal mycelium.

[0029] In this invention, the solid plate culture medium preferably comprises the following components: 10-20 g / L agar, 5-15 g / L glucose or sucrose, and 100-200 g / L potato.

[0030] In this invention, the inoculation preferably includes the following steps: collecting fungal mycelia in sterile water, inoculating the sterile water containing mycelia into the seed culture medium at a volume ratio of 1~5:20~80, and culturing at 20~30 ℃ and 50~200 rpm for 3~10 days to obtain seed liquid.

[0031] In this invention, the seed culture medium preferably comprises the following components: 5-15 g / L glucose or sucrose, and 100-200 g / L potato.

[0032] In this invention, the liquid deep fermentation preferably includes the following steps: inoculating the seed liquid into the liquid deep fermentation medium at a volume ratio of 1~5:20~80, and culturing it for 3~10 days at 20~30 ℃, rotation speed of 50~200 rpm and oxygen flow rate of 2~10 L / min.

[0033] In this invention, the liquid deep fermentation medium preferably comprises the following components: 2-10 g / L glucose or sucrose, 20-40 g / L wheat bran, 20-40 g / L corn flour, 1-3 g / L peptone, and 0.2-1 g / L potassium dihydrogen phosphate or dipotassium hydrogen phosphate.

[0034] The fungal fermentation polysaccharide provided by this invention is derived from edible fungi and has the advantages of being natural, safe, and free of chemically synthesized ingredients, fully meeting the needs of modern consumers for clean-label foods.

[0035] In this invention, the precipitation is preferably carried out in ethanol.

[0036] In this invention, the alcohol used for washing is preferably ethanol.

[0037] In this invention, the freeze-drying temperature is preferably -20 °C, and the freeze-drying time is preferably 24 to 120 hours.

[0038] The present invention also provides fungal fermentation polysaccharides obtained by the preparation method described above, including dextran, mannan, heteropolysaccharides or glycopeptides.

[0039] In this invention, the molecular weight of the fungal fermentation polysaccharide is preferably 10-2000 kDa, more preferably 100-1600 kDa, and even more preferably 500-1200 kDa.

[0040] The fungal fermentation polysaccharide used in this invention has higher biological activity and functionality compared with the hot water extraction polysaccharide in the prior art, and can provide better freeze stability and water retention.

[0041] The present invention also provides the application of the fungal fermented polysaccharide described above in frozen raw steamed buns.

[0042] This invention solves the quality deterioration problem of frozen raw buns during the freezing process by fermenting polysaccharides with fungi. In particular, it solves the problems of poor elasticity, cracking of the dough, collapse after steaming, and dryness of frozen raw buns after steaming. It ensures that the buns can restore their original volume, elasticity and taste after steaming, making the buns structurally intact, elastic and strong after steaming recovery, and close to the quality of fresh buns.

[0043] The present invention also provides a frozen raw bun, which is prepared from the following raw materials in parts by weight: 100 parts flour, 46-50 parts water, 0.5-4 parts yeast, 2-10 parts sugar and 0.05-10 parts fungal fermentation polysaccharide; wherein the fungal fermentation polysaccharide is the fungal fermentation polysaccharide described in the above scheme.

[0044] The frozen raw buns provided by this invention comprise 100 parts by weight.

[0045] Based on the flour, the frozen raw buns provided by the present invention include 46 to 50 parts of water, preferably 47 to 49 parts, and more preferably 48 parts.

[0046] Based on the flour, the frozen raw buns provided by the present invention include 0.5 to 4 parts of yeast, preferably 1 to 3 parts, and more preferably 2 parts.

[0047] Based on the flour, the frozen raw buns provided by the present invention include 2 to 10 parts of sugar, preferably 4 to 8 parts, and more preferably 6 parts.

[0048] In this invention, the sugar is preferably white granulated sugar.

[0049] Based on the flour, the frozen raw buns provided by the present invention include 0.05 to 10 parts of fungal fermented polysaccharide, preferably 2 to 8 parts, more preferably 4 to 6 parts, and even more preferably 5 parts.

[0050] In this invention, the raw materials for the frozen raw buns preferably also include pregelatinized starch; the mass fraction of the pregelatinized starch is preferably 2 to 15 parts, more preferably 5 to 10 parts, and even more preferably 8 parts.

[0051] In this invention, the raw materials for the frozen raw buns preferably also include fillings; the fillings preferably include one or more of vegetable fillings, meat fillings, and bean fillings; the vegetable filling is preferably Shanghai bok choy filling; the meat filling is preferably pork filling; and the bean filling is preferably red bean paste filling. This invention does not have special requirements on the amount of fillings used; conventional amounts are sufficient.

[0052] The present invention also provides a method for preparing the frozen raw buns described above, comprising the following steps: Flour, water, yeast, sugar, and fungal fermentation polysaccharide are mixed (referred to as the first mixture, resulting in dough), and then shaped, proofed, quick-frozen, and frozen to obtain the frozen raw buns; the fungal fermentation polysaccharide is the fungal fermentation polysaccharide described in the above scheme.

[0053] In this invention, the first mixing preferably includes sequential slow mixing and rapid mixing; the slow mixing is preferably stirring mixing, the stirring speed is preferably 40-60 rpm, more preferably 50 rpm; the slow mixing time is preferably 4 min; the rapid mixing is preferably stirring mixing, the stirring speed is preferably 120-150 rpm, more preferably 130-140 rpm; the rapid mixing time is preferably 8 min. This invention uses segmented stirring, first mixing the raw materials at a low speed until they are uniformly formed into a dough, and then rapidly stirring until the gluten network is fully formed.

[0054] In this invention, the shaping preferably includes the following steps: pressing the dough obtained from the first mixing into sheets, dividing it, rolling it out, filling it, sealing it, and shaping it into a bun shape.

[0055] In this invention, the target thickness of the dough sheet is preferably 3-8 mm, more preferably 5-6 mm; the equipment for pressing the dough sheet is preferably a dough press machine; the target weight of the portion is preferably 25-35 grams, more preferably 30 grams; and the weight of the filling is preferably 15-25 grams, more preferably 20 grams. This invention obtains bun dough by dividing the dough into portions, rolling out the dough to obtain bun wrappers, filling the filling, and sealing the edges to obtain a raw bun without a bun shape. This raw bun is then shaped into a bun shape.

[0056] In this invention, the proofing temperature is preferably 25-32 degrees Celsius, more preferably 27-30 degrees Celsius, the relative humidity is preferably 70-85%, more preferably 75-80%, and the heat preservation time is preferably based on the expansion of the dough volume of the bun dough by 1.2-2 times, specifically preferably 30-60 minutes, more preferably 40-50 minutes, and even more preferably 45 minutes.

[0057] In this invention, the quick-freezing temperature is preferably -30 to -45 degrees Celsius, more preferably -35 to -40 degrees Celsius, and the holding time is preferably based on the center temperature of the bun dough being below -18 degrees Celsius, specifically preferably 25 to 35 minutes, more preferably 30 minutes; the quick-freezing is preferably carried out under forced air circulation conditions; the quick-freezing equipment is preferably a freezing tunnel or a quick-freezing cabinet.

[0058] In this invention, the preferred freezing temperature is -20 degrees Celsius; the preferred freezing equipment is a freezer or a cold storage room.

[0059] The present invention also provides a steamed bun, which is obtained by steaming frozen raw steamed buns; the frozen raw steamed buns are the frozen raw steamed buns described in the above scheme or the frozen raw steamed buns obtained by the preparation method described in the above scheme.

[0060] The present invention also provides a method for preparing the steamed buns described above, comprising the following steps: Frozen raw buns are steamed to obtain buns; the frozen raw buns are the frozen raw buns described in the above scheme or the frozen raw buns obtained by the preparation method described in the above scheme.

[0061] In this invention, the steaming temperature is preferably 100 degrees Celsius, the pressure is atmospheric pressure, and the heat preservation time is preferably 15 to 20 minutes, more preferably 15 minutes.

[0062] To further illustrate the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.

[0063] In a specific embodiment of the present invention, the components of the culture medium used are as follows: Solid plate culture medium (i.e. potato agar medium) contains the following components: 10-20 g / L agar, 5-15 g / L glucose or sucrose, and 100-200 g / L potato.

[0064] Seed culture medium (i.e. potato liquid culture medium) contains the following components: 5-15 g / L glucose or sucrose, 100-200 g / L potato.

[0065] The liquid submerged fermentation medium contains the following components: 2-10 g / L glucose or sucrose, 20-40 g / L wheat bran, 20-40 g / L corn flour, 1-3 g / L peptone, and 0.2-1 g / L potassium dihydrogen phosphate or dipotassium hydrogen phosphate.

[0066] Example 1 This embodiment prepares a frozen raw red bean paste (sweet) bun. The quality of the frozen raw bun is improved by utilizing shiitake mushroom fermentation polysaccharides. The specific preparation steps are as follows: (1) Food-grade shiitake mushroom fruiting bodies were used as raw materials, and were washed and set aside. Under aseptic conditions, a 1 cm section was selected in the aseptic area in the middle of the fruiting body. 3Fungal fruiting bodies of varying sizes were inoculated onto potato agar medium and cultured at 25 °C for 5 days. The mycelium of *Lentinula edodes* fungi from the solid plates was collected in 5 mL of sterile water. This sterile water containing mycelium was then inoculated into a shake flask containing 50 mL of potato liquid medium and cultured at 25 °C and 120 rpm for 5 days. The seed culture was collected and inoculated into 5 L of liquid submerged fermentation medium at a volume ratio of 1:5. The culture was then carried out at 26 °C, 200 rpm, and an oxygen flow rate of 10 L / min for 5 days. The culture was filtered and collected to obtain the liquid submerged fermentation broth of *Lentinula edodes*.

[0067] The prepared shiitake mushroom liquid deep fermentation broth was precipitated in ethanol, washed with ethanol, and freeze-dried at -20 ℃ for 24 hours to obtain shiitake mushroom fermentation polysaccharide, which was a light yellow powder.

[0068] (2) Take 1000 g of flour, add 20 g of dry yeast, 80 g of white sugar, 480 mL of water and 5 g of shiitake mushroom fermentation polysaccharide (accounting for 0.5% of the flour mass), and use segmented mixing. First, slowly mix at a low speed of 50 rpm for 4 minutes to mix the ingredients evenly. After the dough is evenly formed, quickly mix at a speed of 130 rpm for 8 minutes until the gluten network is fully formed, resulting in a smooth, soft and elastic dough. Roll the dough three times with a pasta machine at a 5 mm gap to form a smooth sheet. Divide the dough into 30 g portions, roll them out, wrap 20 g of red bean paste inside, and pinch the opening closed to obtain round bun blanks. Place the bun blanks in a proofing box at a temperature of 30 ℃ and a relative humidity of 80% for 50 minutes. The proofed dough is placed in a quick-freezing machine (-40 ℃) and quick-frozen for 30 minutes until the core temperature reaches -18 ℃. Then it is transferred to a -20 ℃ freezer for storage to obtain frozen red bean paste (sweet) buns. After 30 days, it is taken out and steamed at normal pressure for 15 minutes to obtain red bean paste (sweet) buns.

[0069] Example 2 This embodiment prepares a frozen raw Shanghai bok choy (vegetable) bun. The quality of the frozen raw bun is improved by utilizing fermented polysaccharides from wood ear mushrooms. The specific preparation steps are as follows: (1) Food-grade wood ear fruiting bodies were used as raw materials, and were washed and set aside. Under aseptic conditions, a 1 cm section was selected from the aseptic area in the middle of the fruiting body. 3Fungal fruiting bodies of varying sizes were inoculated onto potato agar medium and cultured at 25 °C for 5 days. The mycelium of the fungus was collected from solid plates and placed in 5 mL of sterile water. This sterile water containing the mycelium was then inoculated into a shake flask containing 50 mL of potato liquid medium and cultured at 25 °C and 120 rpm for 5 days. The seed culture was collected and inoculated into 5 L of liquid submerged fermentation medium at a volume ratio of 1:5. The culture was then carried out at 26 °C, 200 rpm, and an oxygen flow rate of 10 L / min for 5 days. The culture was filtered and collected to obtain the Auricularia auricula-judae liquid submerged fermentation broth.

[0070] The prepared Auricularia auricula-judae liquid deep fermentation broth was precipitated in ethanol, washed with ethanol, and freeze-dried at -20℃ for 120 hours to obtain Auricularia auricula-judae fermented polysaccharide, which was a light yellow powder.

[0071] (2) Take 1000 g of flour, add 20 g of dry yeast, 80 g of white sugar, 480 mL of water and 5 g of wood ear fermentation polysaccharide (accounting for 0.5% of the flour mass), and use segmented mixing. First, slowly mix at a low speed of 50 rpm for 4 minutes to mix the ingredients evenly. After the dough is evenly formed, quickly mix at a speed of 130 rpm for 8 minutes until the gluten network is fully formed, resulting in a smooth, soft and elastic dough. Roll the dough three times with a pasta machine at a 5 mm gap to form a smooth sheet. Divide the dough into 30 g portions, roll them out, wrap 20 g of Shanghai bok choy filling inside, and pinch the edges closed to obtain round buns. Place the buns in a proofing box at 30 ℃ and 80% relative humidity for 50 minutes to proof. The proofed dough is placed in a quick-freezing machine (-40 ℃) and quick-frozen for 30 minutes until the core temperature reaches -18 ℃. Then it is transferred to a -20 ℃ freezer for storage to obtain frozen raw Shanghai bok choy (vegetable) buns. After 30 days, it is taken out and steamed at normal pressure for 15 minutes to obtain Shanghai bok choy (vegetable) buns.

[0072] Example 3 This embodiment prepares a frozen raw pork bun, utilizing shiitake mushroom fermentation polysaccharides and wood ear mushroom fermentation polysaccharides to improve the quality of the frozen raw bun. The specific preparation steps are as follows: (1) The preparation method is the same as in Example 1, and the fermented polysaccharide of shiitake mushroom is obtained as a light yellow powder.

[0073] (2) The preparation method is the same as in Example 2, and the fermented polysaccharide of black fungus is obtained as a light yellow powder.

[0074] (3) Take 1000 g of flour, add 20 g of dry yeast, 80 g of white sugar, 480 mL of water, 2 g of shiitake mushroom fermentation polysaccharide and 3 g of wood ear mushroom fermentation polysaccharide (totaling 0.5% of the flour mass), and use segmented mixing. First, slowly mix at a low speed of 50 rpm for 4 minutes to mix the ingredients evenly. After the dough is evenly formed, quickly mix at a speed of 130 rpm for 8 minutes until the gluten network is fully formed, resulting in a smooth, soft and elastic dough. Roll the dough three times with a pasta machine at a 5 mm gap to form a smooth sheet, divide it into 30 g portions, roll them out, wrap 20 g of pork filling inside, and pinch the opening closed to obtain round bun blanks. Place the bun blanks in a proofing box at a temperature of 30 ℃ and a relative humidity of 80% for 50 minutes. The proofed dough is placed in a quick-freezing machine (-40 ℃) and quick-frozen for 30 minutes until the core temperature reaches -18 ℃. Then it is transferred to a -20 ℃ freezer for storage to obtain frozen pork buns. After 30 days, it is taken out and steamed at normal pressure for 15 minutes to obtain pork buns.

[0075] Example 4 This embodiment prepares a frozen raw red bean paste (sweet) bun. The quality of the frozen raw bun is improved by utilizing shiitake mushroom fermentation polysaccharides. The specific preparation steps are as follows: (1) The preparation method is the same as in Example 1, and the fermented polysaccharide of shiitake mushroom is obtained as a light yellow powder.

[0076] (2) Take 1000 g of flour, add 20 g of dry yeast, 80 g of white sugar, 480 mL of water and 10 g of shiitake mushroom fermentation polysaccharide (accounting for 1.0% of the flour mass), and use segmented mixing. First, slowly mix at a low speed of 50 rpm for 4 minutes to mix the ingredients evenly. After the dough is evenly formed, quickly mix at a speed of 130 rpm for 8 minutes until the gluten network is fully formed, resulting in a smooth, soft and elastic dough. Roll the dough three times with a pasta machine at a 5 mm gap to form a smooth sheet. Divide the sheet into 30 g portions, roll them out, wrap 20 g of red bean paste inside, and pinch the edges to seal, resulting in round buns. Place the buns in a proofing box at 30 ℃ and 80% relative humidity for 50 minutes to proof. The proofed dough is placed in a quick-freezing machine (-40 ℃) and quick-frozen for 30 minutes until the core temperature reaches -18 ℃. Then it is transferred to a -20 ℃ freezer for storage to obtain frozen red bean paste (sweet) buns. After 30 days, it is taken out and steamed at normal pressure for 15 minutes to obtain red bean paste (sweet) buns.

[0077] Example 5 This embodiment prepares a frozen raw red bean paste (sweet) bun. The quality of the frozen raw bun is improved by utilizing shiitake mushroom fermentation polysaccharides. The specific preparation steps are as follows: (1) The preparation method is the same as in Example 1, and the fermented polysaccharide of shiitake mushroom is obtained as a light yellow powder.

[0078] (2) Take 1000 g of flour, add 20 g of dry yeast, 80 g of white sugar, 480 mL of water and 15 g of shiitake mushroom fermentation polysaccharide (accounting for 1.5% of the flour mass), and use segmented mixing. First, slowly mix at a low speed of 50 rpm for 4 minutes to mix the ingredients evenly. After the dough is evenly formed, quickly mix at a speed of 130 rpm for 8 minutes until the gluten network is fully formed, resulting in a smooth, soft and elastic dough. Roll the dough three times with a pasta machine at a 5 mm gap to form a smooth sheet. Divide the dough into 30 g portions, roll them out, wrap 20 g of red bean paste inside, and pinch the opening closed to obtain round bun blanks. Place the bun blanks in a proofing box at a temperature of 30 ℃ and a relative humidity of 80% for 50 minutes. The proofed dough is placed in a quick-freezing machine (-40 ℃) and quick-frozen for 30 minutes until the core temperature reaches -18 ℃. Then it is transferred to a -20 ℃ freezer for storage to obtain frozen red bean paste (sweet) buns. After 30 days, it is taken out and steamed at normal pressure for 15 minutes to obtain red bean paste (sweet) buns.

[0079] Comparative Example 1 This comparative example prepared a frozen raw red bean paste (sweet) bun. The specific preparation steps are as follows: Take 1000 g of flour, add 20 g of dry yeast, 80 g of sugar, and 480 mL of water. Mix in stages: first, slowly mix at 50 rpm for 4 minutes to combine the ingredients evenly; after forming a smooth dough, then quickly mix at 130 rpm for 8 minutes until the gluten network is fully formed, resulting in a smooth, soft, and elastic dough. Roll the dough three times with a pasta machine at 5 mm intervals to form a smooth sheet. Divide the sheet into 30 g portions, roll each portion into a wrapper, fill with 20 g of red bean paste, and pinch the edges to seal, resulting in round buns. Place the buns in a proofing box at 30 ℃ and 80% relative humidity for 50 minutes. After proofing, place the buns in a quick-freezing machine (-40 ℃) for 30 minutes until the core temperature reaches -18 ℃, then transfer to a -20 ℃ freezer to obtain frozen red bean paste (sweet) buns. Take them out after 30 days and steam them under normal pressure for 15 minutes to get red bean paste (sweet) buns.

[0080] Comparative Example 2 This comparative example prepared a regular red bean paste (sweet) bun. The specific preparation steps are as follows: Take 1000g of flour, add 20g of dry yeast, 80g of white sugar, and 480mL of water. Mix in stages: first, slowly mix at 50 rpm for 4 minutes to combine the ingredients; after forming a smooth dough, then quickly mix at 130 rpm for 8 minutes until the gluten network is fully formed, resulting in a smooth, soft, and elastic dough. Roll the dough three times with a pasta machine at 5mm intervals to form a smooth sheet. Divide the sheet into 30g portions, roll each portion into a wrapper, fill with 20g of red bean paste, and seal tightly to obtain round, sweet red bean paste buns. Steam the buns under normal pressure for 15 minutes to obtain sweet red bean paste buns.

[0081] Test Example 1 The steamed buns obtained from Examples 1-3 and Comparative Examples 1-2 were tested. Their sensory qualities, such as the smoothness of the skin, color, appearance, and elasticity, as well as the texture, specific volume, and organizational structure of the buns, were analyzed and evaluated. A 9-point scoring system was used, and the scores were converted according to the corresponding weights in Table 1. The results are shown in Table 2.

[0082] Table 1. Scoring Criteria and Weighting for Steamed Buns

[0083] Table 2. Scoring results of Examples 1-3 and Comparative Examples 1-2

[0084] As shown in Table 2, Examples 1-5 of this invention, by adding different types and proportions of fungal fermentation polysaccharides, achieved higher overall scores than Comparative Example 1, indicating that the addition of fungal fermentation polysaccharides can effectively improve the quality deterioration of raw steamed buns under freezing conditions. Meanwhile, Examples 4 and 5 scored higher than Examples 1 and 2, indicating that a higher proportion of fungal fermentation polysaccharides can improve quality deterioration under freezing conditions and impart better texture and flavor characteristics to the raw steamed buns. These results demonstrate that this invention utilizes fermented fungal polysaccharides to improve the quality of frozen raw steamed buns, effectively addressing the serious quality deterioration problems such as easy cracking of the dough, collapse after steaming, and poor texture and elasticity during refrigeration. It maintains the structural integrity and good elasticity of frozen raw steamed buns after steaming, improving the frozen storage quality of frozen steamed buns, bringing their quality close to that of fresh steamed buns (Comparative Example 2).

[0085] The embodiments of the present invention have been described above; however, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A method for preparing polysaccharides by fungal fermentation, characterized in that, Includes the following steps: The fungal liquid deep fermentation broth was subjected to precipitation, alcohol washing, and freeze-drying in sequence to obtain the fungal fermentation polysaccharide.

2. The preparation method according to claim 1, characterized in that, The fungal liquid deep fermentation broth is prepared using food-grade fungal fruiting bodies, which include one or more of the following: shiitake mushrooms, Ganoderma lucidum, Grifola frondosa, Tremella fuciformis, Hericium erinaceus, and Auricularia auricula-judae.

3. The preparation method according to any one of claims 1 to 2, characterized in that, The freeze-drying temperature is -20℃, and the freeze-drying time is 24~120 hours.

4. The fungal fermentation polysaccharide obtained by the preparation method according to any one of claims 1 to 3, characterized in that, This includes glucan, mannan, heteropolysaccharides, or glycopeptides.

5. The fungal fermentation polysaccharide according to claim 4, characterized in that, The molecular weight of the fungal fermentation polysaccharide is 10~2000 kDa.

6. The use of the fungal fermented polysaccharide according to any one of claims 4 to 5 in frozen raw buns.

7. A frozen raw bun, characterized in that, The mixture is prepared from the following raw materials in parts by weight: 100 parts flour, 46-50 parts water, 0.5-4 parts yeast, 2-10 parts sugar and 0.05-10 parts fungal fermentation polysaccharide; wherein the fungal fermentation polysaccharide is the fungal fermentation polysaccharide described in any one of claims 4-5.

8. The method for preparing frozen raw buns according to claim 7, characterized in that, Includes the following steps: Flour, water, yeast, sugar and fungal fermentation polysaccharide are mixed and then shaped, proofed, quick-frozen and frozen to obtain the frozen raw buns; the fungal fermentation polysaccharide is the fungal fermentation polysaccharide according to any one of claims 4 to 5.

9. A type of steamed bun, characterized in that, It is obtained by steaming frozen raw buns; the frozen raw buns are the frozen raw buns described in claim 7 or the frozen raw buns obtained by the preparation method described in claim 8.

10. The method for preparing the steamed bun according to claim 9, characterized in that, Includes the following steps: The frozen raw buns are steamed to obtain buns; the frozen raw buns are the frozen raw buns described in claim 7 or the frozen raw buns obtained by the preparation method described in claim 8.

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