Edible blood product composite modifier, sheep blood tofu and method

Abstract

The invention provides an edible blood product composite modifier, sheep blood tofu and a method, the edible blood product composite modifier comprises a water-retaining agent and an antioxidant, and the water-retaining agent comprises elm bark glue, sa-hao seed glue and konjac glucomannan; the antioxidant comprises buckwheat flavone. According to the invention, a composite modifier composed of natural plant resource water-retaining agents such as elm bark glue, artemisia glue and konjac glucomannan and a natural plant resource antioxidant buckwheat flavone is screened and added into the sheep blood tofu, so that the quality of the sheep blood tofu is well improved, the oxidation discoloration of the sheep blood tofu is effectively inhibited, and the quality of the sheep blood tofu is improved. Moreover, the unfreezing loss rate and the high-temperature sterilization loss rate are respectively reduced by 26.38% and 15.45%, the water retention rate and the yield of the sheep blood tofu are effectively improved, and the honeycomb structure of the sheep blood tofu after unfreezing and high-temperature sterilization can be remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of processing of sheep blood tofu, and particularly relates to an edible blood product composite improver, sheep blood tofu and a method thereof. Background Art

[0002] Sheep blood is a by-product in the slaughter and processing of sheep. It is rich in protein and iron and is an ideal high-quality food resource for protein and iron supplementation. As a traditional delicacy, sheep blood tofu has a broad market prospect. However, in sheep slaughter and processing enterprises, due to the large amount of blood produced, the sheep blood tofu processed by traditional methods is not sterilized, has poor preservation performance and a short shelf life. Although freezing storage or high-temperature sterilization (121 °C, 30 min) can improve the preservation performance, after freezing storage and high-temperature sterilization, the sheep blood tofu will form a honeycomb structure due to water loss, seriously affecting the quality of the sheep blood tofu. Moreover, due to oxidation during the processing, the color of the sheep blood tofu will become darker, affecting the aesthetics of the product. The above reasons lead to a large amount of sheep blood being discarded by sheep slaughter and processing enterprises, not only causing a great waste of resources, but also polluting the environment. Therefore, how to improve the water retention performance, preservation performance and quality of sheep blood tofu is an urgent technical problem to be solved by sheep processing enterprises. Summary of the Invention

[0003] In order to solve the problems existing in the prior art, the present invention provides an edible blood product composite improver, sheep blood tofu and a method thereof. By screening a composite improver composed of natural plant resource water retainers, namely elm bark gum, artemisia sphaerocephala gum and konjac glucomannan, and a natural plant resource antioxidant, namely buckwheat flavonoids, and adding it to the sheep blood tofu, the oxidation discoloration of the sheep blood tofu is effectively inhibited, and the color aesthetics of the sheep blood tofu is improved; the thawing loss rate and high-temperature sterilization loss rate of the sheep blood tofu are respectively reduced by 26.38% and 15.45%, effectively improving the water retention rate and the yield rate of the sheep blood tofu, and the honeycomb structure of the sheep blood tofu after thawing and high-temperature sterilization can also be significantly improved. It shows that the natural composite improver screened by the present invention has a good improvement effect on the quality of sheep blood tofu.

[0004] To achieve the above object, the present invention provides the following technical solution: An edible blood product composite improver, comprising a water retainer and an antioxidant, wherein the water retainer includes elm bark gum, artemisia sphaerocephala gum and konjac glucomannan; the antioxidant includes buckwheat flavonoids.

[0005] Further, based on the weight ratio of the blood raw material, the water retainer includes 0.2% - 0.4% of elm bark gum, 0.2% - 0.4% of artemisia sphaerocephala gum and 0.1% - 0.3% of konjac glucomannan; the antioxidant includes 0.2% - 0.4% of buckwheat flavonoids.

[0006] Further, based on the weight ratio of the blood raw material, the water retention agent includes 0.2% of elm bark gum, 0.3% of artemisia sphaerocephala gum, and 0.2% of konjac glucomannan; the antioxidant includes 0.3% of buckwheat flavonoids.

[0007] Further, the preparation of the elm bark gum is as follows: The dry elm bark is crushed and then extracted with water. The material-liquid ratio is 1:10, the extraction temperature is 90°C to 95°C, and the extraction time is 4h to 6h. After filtration, the filtrate is obtained; The filtrate is precipitated with ethanol for 12h to 16h, filtered, and the precipitate is vacuum freeze-dried to obtain elm bark gum.

[0008] Further, the preparation of the artemisia sphaerocephala gum is as follows: The dry artemisia sphaerocephala seeds are crushed and then extracted with water. The material-liquid ratio is 1:8 to 1:12, the extraction temperature is 90°C to 95°C, and the extraction time is 4h to 6h. After filtration, the filtrate is obtained; The filtrate is precipitated with ethanol for 12h to 16h, filtered, the ethanol in the filtrate is recovered, and the obtained precipitate is vacuum freeze-dried to obtain artemisia sphaerocephala gum.

[0009] Further, the preparation of the buckwheat flavonoids is as follows: The dry buckwheat straw is crushed and then extracted with an ethanol aqueous solution at room temperature. The concentration of the ethanol aqueous solution is 75%, the material-liquid ratio is 1:8 to 1:12, and the extraction time is 12h to 16h. After filtration, the filtrate is concentrated under reduced pressure to a thick paste state and then vacuum freeze-dried to obtain buckwheat flavonoids.

[0010] The present invention also provides a sheep blood tofu, and the above-mentioned one kind of edible blood product composite improver is added during the preparation, and the addition amount of the composite improver is based on the weight ratio of the sheep blood.

[0011] Further, a coagulant is also added to the sheep blood tofu.

[0012] The present invention also provides a preparation method of the sheep blood tofu, and the specific steps are as follows: An anticoagulant is added to the fresh sheep blood to obtain anticoagulated sheep blood; A coagulant and the above-mentioned one kind of edible blood product composite improver are added to the anticoagulated sheep blood, stirred evenly and then heated, and poured into a mold and left to stand and cool at room temperature to solidify into fresh sheep blood tofu.

[0013] Further, the anticoagulant is a sodium citrate solution with a concentration of 0.5%, and the addition ratio of the sodium citrate solution to the fresh sheep blood is 1:1; The coagulant is calcium chloride, and the addition amount is 0.5% of the weight of the sheep blood.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides an edible blood product composite improver. Through the compounding technology of natural plant resources, elm bark gum, artemisia sphaerocephala gum and konjac glucomannan are synergistically used as water retention agents, combined with the antioxidant properties of buckwheat flavonoids, to construct a multi-functional composite improvement system. Elm bark gum and artemisia sphaerocephala gum form a three-dimensional network structure to enhance water retention, konjac glucomannan further fills the voids to improve the gel strength, and buckwheat flavonoids block the oxidation chain reaction by scavenging free radicals. The synergistic effect of the four reduces the thawing loss rate of sheep blood tofu by 26.38% and the loss rate during high-temperature sterilization by 15.45%, significantly improving the processing stability and water retention performance of the product.

[0015] The composite improver optimizes the microstructure of blood tofu through the intermolecular interaction of natural polysaccharides, making the honeycomb pore distribution more uniform after freezing-thawing and high-temperature treatment, and effectively inhibiting the juice loss caused by protein denaturation. At the same time, the natural pigment stabilizing effect of buckwheat flavonoids improves the red brightness of the product color, and the shelf life is extended compared with the traditional process, achieving a double breakthrough in functionality and economy.

[0016] The present invention also provides a sheep blood tofu added with the composite improver, which uses all-plant-source additives to replace chemical synthetic improvers. Raw materials such as elm bark gum and artemisia sphaerocephala gum are obtained through food-grade extraction processes. The precise ratio of anticoagulant (sodium citrate) and coagulant (calcium chloride) in the production process ensures the gel strength and food safety of blood tofu, expanding the application scenarios and consumer groups of blood products. Specific Embodiments

[0017] The following further illustrates the present invention in conjunction with specific embodiments.

[0018] The present invention provides an edible blood product composite improver, including a water retention agent and an antioxidant, wherein the water retention agent includes elm bark gum, artemisia sphaerocephala gum and konjac glucomannan; the antioxidant uses buckwheat flavonoids.

[0019] Preferably, based on the weight ratio of the blood raw material, the above composite improver includes 0.2% of elm bark gum, 0.3% of artemisia sphaerocephala gum, 0.2% of konjac glucomannan and 0.3% of buckwheat flavonoids; Preferably, the preparation of elm bark gum is as follows: Crush dry elm bark and extract it with water, the material-liquid ratio is 1:8~1:12, the extraction temperature is 90℃~95℃, the extraction time is 4h~6h, and then filter; precipitate the filtrate with ethanol (filtrate: 95% ethanol (v / v) is 1:4) for 12h~16h, filter, and the precipitate is vacuum freeze-dried to obtain elm bark gum.

[0020] Preferably, the preparation of artemisia sphaerocephala gum is as follows: Crush the dry Artemisia sphaerocephala seeds and extract them with water. The ratio of material to liquid is 1:8 - 1:12, the extraction temperature is 90°C - 95°C, and the extraction time is 4h - 6h. Then filter. Precipitate the filtrate with ethanol (the ratio of filtrate to 95% ethanol (v / v) is 1:4) for 12h - 16h, filter, recover the ethanol from the filtrate under reduced pressure using a rotary evaporator, and vacuum freeze-dry the precipitate to obtain Artemisia sphaerocephala gum.

[0021] Preferably, the preparation of buckwheat flavonoids is as follows: Crush the dry buckwheat straw and extract it with an aqueous ethanol solution at room temperature. The concentration of the aqueous ethanol solution is 75%, the ratio of material to liquid is 1:8 - 1:12, and the extraction time is 12h - 16h. Then filter. Concentrate the filtrate to a thick paste under reduced pressure using a rotary evaporator, and vacuum freeze-dry it to obtain buckwheat flavonoids. The ethanol can be recovered and reused.

[0022] When preparing sheep blood tofu using the above natural plant resource composite improver for sheep blood tofu quality, the specific steps are as follows: 1. Treatment of sheep blood Add a 0.5% sodium citrate solution to the freshly received sheep blood at a ratio of 1:1, stir evenly to prevent blood coagulation, and store it at 4°C for later use to obtain anticoagulated sheep blood.

[0023] 2. Processing of sheep blood tofu Add 0.5% calcium chloride, 0.2% elm bark gum, 0.3% Artemisia sphaerocephala gum, 0.2% konjac glucomannan, and 0.3% buckwheat flavonoids based on the weight of the sheep blood to the anticoagulated sheep blood. Stir evenly and then heat. Pour it into a mold and let it stand at room temperature to cool and solidify to form fresh sheep blood tofu.

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0025] Example 1 1 Materials and methods 1.1 Materials Sheep blood: Provided by Yulin Hengshan Vanilla Mutton Products Co., Ltd.

[0026] Elm bark, Artemisia sphaerocephala seeds, and buckwheat straw were purchased from the farmers' market in Hengshan District, Yulin City. Konjac glucomannan was purchased from Ankang Baisheng Biotechnology Co., Ltd., Shaanxi Province. Table salt and sodium citrate were purchased from the market.

[0027] 1.2 Instrument and equipment YP10002 Electronic Analytical Balance, Yuyao Jinnuo Balance Instrument Co., Ltd.; DGX-9073B-1 Electrically Heated Forced Air Drying Oven, Shanghai Fuma Experimental Equipment Co., Ltd.; GSP-9080MBE Water Bath Thermostatic Incubator, Medical Equipment Factory of Shanghai Boxun Industry Co., Ltd.; PZ(Q)-400 Vacuum Packaging Machine, Wenzhou Xingye Machinery Equipment Co., Ltd.; FY50 High Temperature and High Pressure Steamer, Zhucheng Mingkai Machinery Co., Ltd.; TA-XT plus Texture Analyzer, SNS Company of the UK; CR-5 Color Difference Meter, Konica Minolta (China) Investment Co., Ltd. 1.3 Experimental Contents and Methods 1.3.1 Process Flow Fresh sheep blood → Add anticoagulant → Preservation → Add coagulant calcium chloride and compound modifier → Heating → Pour into mold → Solidification → Sheep blood tofu 1.3.2 Treatment of Sheep Blood Add 0.5% sodium citrate solution to the freshly received slaughtered sheep blood at a ratio of 1:1, stir evenly to prevent blood coagulation, and store it for standby at 4°C.

[0028] 1.3.3 Preparation of Ulmus pumila Gum, Artemisia sphaerocephala Krasch Gum and Buckwheat Flavonoids (1) Preparation of Ulmus pumila Gum: Crush dry Ulmus pumila bark and extract it with water. The solid-liquid ratio is 1:10, the extraction temperature is 90°C, and the extraction time is 4h. Filter; precipitate the filtrate with ethanol [filtrate: 95% ethanol (v / v) is 1:4] for 12h, filter, and vacuum freeze-dry the precipitate to obtain Ulmus pumila Gum.

[0029] (2) Preparation of Artemisia sphaerocephala Krasch Gum: Crush dry Artemisia sphaerocephala Krasch seeds and extract them with water. The solid-liquid ratio is 1:10, the extraction temperature is 90°C, and the extraction time is 4h. Filter; precipitate the filtrate with ethanol [extract: 95% ethanol (v / v) is 1:4] for 12h, filter, recover ethanol from the filtrate by rotary evaporator under reduced pressure, and vacuum freeze-dry the precipitate to obtain Artemisia sphaerocephala Krasch Gum.

[0030] (3) Preparation of Buckwheat Flavonoids: Crush dry buckwheat straw and extract it with aqueous ethanol solution at room temperature. The concentration of the aqueous ethanol solution is 75%, the solid-liquid ratio is 1:10, and the extraction time is 12h. Filter, concentrate the filtrate to a thick paste by rotary evaporator under reduced pressure, and vacuum freeze-dry it to obtain buckwheat flavonoids. Ethanol recovery can be reused.

[0031] 1.3.4 Preparation of Sheep Blood Tofu Add compound modifier and 0.5% calcium chloride of the weight of sheep blood to the anticoagulated sheep blood, stir evenly, heat to 90°C, pour it into the mold, and let it stand and cool at room temperature to solidify into fresh sheep blood tofu.

[0032] 1.3.5 Freezing and Thawing of Sheep Blood Tofu (1)Freezing: Place the freshly prepared sheep blood tofu in a refrigerator at -18°C for freezing storage for more than 24 hours.

[0033] (2)Thawing: Thaw the frozen-stored sheep blood tofu in a microwave oven until all the ice crystals in the tofu disappear.

[0034] 1.3.6 Sterilization of sheep blood tofu Place the freshly prepared sheep blood tofu in a retort sterilizer and sterilize it at 121°C for 30 minutes, then cool it under reverse pressure to 40°C.

[0035] 1.3.7 Optimization of the compound modifier formula 1.3.7.1 Single-factor experiments (1)Effect of the amount of elm bark gum on the texture of sheep blood tofu: Add 0.5% calcium chloride based on the weight of sheep blood and 0, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% elm bark gum to anticoagulated sheep blood respectively, stir evenly, prepare sheep blood tofu according to the method in 1.3.4, and measure the texture indexes of the sheep blood tofu.

[0036] (2)Effect of the amount of Artemisia sphaerocephala Krasch gum on the texture of sheep blood tofu: Add 0.5% calcium chloride based on the weight of sheep blood and 0, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% Artemisia sphaerocephala Krasch gum to anticoagulated sheep blood respectively, stir evenly, prepare sheep blood tofu according to the method in 1.3.4, and measure the texture indexes of the sheep blood tofu.

[0037] (3)Effect of the amount of konjac glucomannan on the texture of sheep blood tofu: Add 0.5% calcium chloride based on the weight of sheep blood and 0, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% konjac glucomannan to anticoagulated sheep blood respectively, stir evenly, prepare sheep blood tofu according to the method in 1.3.4, and measure the texture indexes of the sheep blood tofu.

[0038] (4)Effect of the amount of buckwheat flavonoids on the color of sheep blood tofu: Add 0.5% calcium chloride based on the weight of sheep blood and 0, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% buckwheat flavonoids to anticoagulated sheep blood respectively, stir evenly, prepare sheep blood tofu according to the method in 1.3.4, and measure the color difference of the sheep blood tofu.

[0039] 1.3.7.2 Orthogonal experiments On the basis of the above single-factor experiments, using elm bark gum, Artemisia sphaerocephala Krasch gum, konjac glucomannan, and buckwheat flavonoids as experimental factors and the sensory score of sheep blood tofu as the inspection index, optimize the formula of the compound modifier for sheep blood tofu. The experimental factors and levels are set as shown in Table 1.

[0040] Table 1 Orthogonal experiment factor and level setting table

[0041] 1.3.8 Influence of Compound Modifier on the Quality of Sheep Blood Tofu Prepare sheep blood tofu with the compound modifier optimized by the above orthogonal experiment according to the method in 1.3.4 to obtain fresh sheep blood tofu. Freeze and thaw the prepared fresh sheep blood tofu according to the method in 1.3.5, and sterilize the prepared fresh sheep blood tofu according to the method in 1.3.6. Measure the color difference and texture indexes of fresh sheep blood tofu, thawed sheep blood tofu and sterilized sheep blood tofu respectively, and conduct sensory evaluation. Calculate the thawing loss rate and sterilization loss rate of sheep blood tofu. The control is fresh sheep blood tofu, frozen and thawed sheep blood tofu, and sterilized sheep blood tofu prepared without compound modifier according to the methods in 1.3.4, 1.3.5 and 1.3.6.

[0042] 1.3.9 Quality Evaluation Indexes of Frozen Sheep Blood Tofu 1.3.9.1 Thawing Loss Rate of Sheep Blood Tofu Thaw the frozen-stored sheep blood tofu in a microwave oven, accurately weigh the mass of the sheep blood tofu before and after thawing, and calculate the thawing loss rate according to the following formula.

[0043] Thawing loss rate % = (M1 - M2) / M2 Where: M1 represents the mass of the frozen sheep blood tofu before thawing; M2 represents the mass of the frozen sheep blood tofu after thawing. 1.3.9.2 Sterilization Loss Rate of Sheep Blood Tofu Place the prepared sheep blood tofu in a retort sterilizer, sterilize it at 121 °C for 30 min, and cool it under reverse pressure to 40 °C. Accurately weigh the mass of the sheep blood tofu before and after sterilization, and calculate the sterilization loss rate according to the following formula.

[0044] Sterilization loss rate % = (M1 - M2) / M2 Where: M1 represents the mass of the frozen sheep blood tofu before sterilization; M2 represents the mass of the frozen sheep blood tofu after sterilization.

[0045] 1.3.9.3 Color Difference Cut the sheep blood tofu into cubes of 2 cm × 2 cm × 1 cm, and measure the color of the sheep blood tofu with a colorimeter. L* represents the brightness value, a* represents the red value, and b* represents the yellow value. Each group of samples is measured 3 times and the average value is taken. 1.3.9.4 Texture Measurement The texture of sheep blood tofu was analyzed using a texture analyzer. The sheep blood tofu samples were cut into small cuboids (2 cm×2 cm×1 cm), and the P / 50 probe was used. The measurement parameters were: pre-test speed 2.0 mm / s, test speed 1.0 mm / s, return speed 5.0 mm / s, sample compression ratio 50%, secondary compression interval time 3.0 s, trigger force 5 g, and each group of samples was measured 3 times.

[0046] 1.3.10 Sensory evaluation indicators and scoring criteria The selection of sensory evaluation personnel referred to the corresponding requirements in GB / T14195 "Sensory analysis - Selection and training of sensory analysts - General guidance for the selection of preferred assessors". Ten assessors with a food professional background were selected and trained to form a sensory evaluation panel to conduct sensory evaluation on the quality of sheep blood tofu. The sensory evaluation indicators and scoring criteria are shown in Table 2.

[0047] Table 2 Sensory evaluation indicators and scoring criteria for sheep blood tofu

[0048] 1.3.11 Data processing Excel 2013 software was used for data processing and collation. The data annotation method was mean ± standard deviation, and SPSS19.0 statistical software was used for sum and significance analysis (Duncan method).

[0049] 2 Results and analysis 2.1 Results of single-factor experiments 2.1.1 Effect of the amount of elm bark gum on the texture of sheep blood tofu The results of the effect of the amount of elm bark gum on the texture of sheep blood tofu are shown in Table 3. It can be seen from Table 3 that the hardness, elasticity, cohesiveness, chewiness, and resilience of sheep blood tofu gradually increase with the increase in the amount of elm bark gum. When the amount of elm bark gum is below 0.3%, the increase is relatively large. After exceeding 0.3%, the increase slows down. Considering cost factors, the appropriate amount of elm bark gum is 0.3%.

[0050] Table 3 shows the effect of elm bark gum on the texture of sheep blood tofu

[0051] 2.1.2 Effect of the amount of Artemisia sphaerocephala Krasch gum on the texture of sheep blood tofu The results of the effect of the amount of Artemisia sphaerocephala Krasch gum on the texture of sheep blood tofu are shown in Table 4. It can be seen from Table 4 that the hardness, elasticity, cohesiveness, chewiness, and resilience of sheep blood tofu gradually increase with the increase in the amount of Artemisia sphaerocephala Krasch gum. When the amount of Artemisia sphaerocephala Krasch gum is below 0.3%, the increase is relatively large. After exceeding 0.3%, the increase slows down. Considering cost factors, the appropriate amount of Artemisia sphaerocephala Krasch gum is 0.3%.

[0052] Table 4 shows the effect of Artemisia sphaerocephala gum on the texture of sheep blood tofu

[0053] 2.1.3 Effect of the dosage of konjac glucomannan on the texture of sheep blood tofu The results of the effect of the dosage of konjac glucomannan on the texture of sheep blood tofu are shown in Table 5. It can be seen from Table 5 that the effect of konjac glucomannan on the texture of sheep blood tofu is relatively significant. The hardness and cohesiveness of sheep blood tofu gradually increase with the increase of the dosage of konjac glucomannan. However, the elasticity, chewiness and resilience first increase and then decrease with the increase of the dosage of konjac glucomannan. When the dosage of konjac glucomannan is 0.2%, the elasticity, chewiness and resilience of sheep blood tofu are the largest. After exceeding 0.2%, the elasticity, chewiness and resilience of sheep blood tofu gradually decrease with the increase of the concentration of konjac glucomannan. Therefore, the dosage of konjac glucomannan is preferably 0.2%.

[0054] Table 5 shows the effect of konjac glucomannan on the texture of sheep blood tofu

[0055] 2.1.4 Effect of the dosage of buckwheat flavonoids on the color of sheep blood tofu The results of the effect of the dosage of buckwheat flavonoids on the color of sheep blood tofu are shown in Table 6. It can be seen from Table 6 that buckwheat flavonoids have a certain effect on the color of sheep blood tofu. The color beauty of sheep blood tofu gradually increases with the increase of the dosage of buckwheat flavonoids. This is because buckwheat flavonoids have strong antioxidant ability and can inhibit the oxidation and discoloration of sheep blood heme. 0.3% of buckwheat flavonoids can effectively inhibit the oxidation and discoloration of sheep blood and improve the color beauty of sheep blood tofu. Further increasing the dosage of buckwheat flavonoids, although the color beauty of sheep blood tofu can also increase to some extent, the increase amplitude is not obvious. Therefore, the dosage of buckwheat flavonoids is preferably 0.3%.

[0056] Table 6 shows the effect of buckwheat flavonoids on the color of sheep blood tofu

[0057] 2.2 Results of orthogonal experiments On the basis of the above single-factor experiments, taking elm bark gum, Artemisia sphaerocephala gum, konjac glucomannan and buckwheat flavonoids as experimental factors and the sensory score of sheep blood tofu as the inspection index, the formula of the compound improver for sheep blood tofu was optimized. The results of the orthogonal experiment are shown in Table 7

[0058] Table 7 is the result table of the orthogonal experiment

[0059] It can be seen from the range analysis of the orthogonal experiment that among the four factors, konjac glucomannan has the most significant effect on the sensory quality of sheep blood tofu. The order of the influence of each factor on the sensory quality of sheep blood tofu from strong to weak is konjac glucomannan > buckwheat flavonoids > elm bark gum > Artemisia sphaerocephala Krasch gum. The optimal combination of the composite improver for sheep blood tofu is A1B2C3D2, that is, the dosages of elm bark gum, Artemisia sphaerocephala Krasch gum, konjac glucomannan, and buckwheat flavonoids are 0.2%, 0.3%, 0.2%, and 0.3% of the sheep blood quality respectively. The total sensory score of sheep blood tofu is 94.4. After verification, the sensory score of sheep blood tofu produced with this composite improver is 93.9.

[0060] 2.3 Effects of the composite improver on the thawing loss rate and sterilization loss rate of sheep blood tofu The effects of the composite improver on the thawing loss rate and sterilization loss rate of sheep blood tofu are shown in Table 8.

[0061] Table 8 shows the effects of the composite quality improver on the thawing loss rate and sterilization loss rate of sheep blood tofu

[0062] It can be seen from Table 8 that after the sheep blood tofu is stored frozen and sterilized at high temperature, the thawing loss rate and sterilization loss rate of the control group are 36.85% and 21.39% respectively, and the thawing loss rate and sterilization loss rate of the treatment group are 10.47% and 5.94% respectively. The thawing loss rate and sterilization loss rate of the treatment group are reduced by 26.38% and 15.45% respectively compared with the control group, indicating that adding the composite improver composed of elm bark gum, Artemisia sphaerocephala Krasch gum, konjac glucomannan, and buckwheat flavonoids can effectively reduce the thawing loss rate and sterilization loss rate of mutton tofu and has a good water retention effect. This is because the composite improver contains rich hydrophilic colloids, which have a strong binding force on water molecules and improve the water retention ability of sheep blood tofu.

[0063] 2.4 Effects of the composite improver on the color of sheep blood tofu The effects of the composite improver on the color of sheep blood tofu are shown in Table 9. In the table, L* represents the brightness value, a* represents the red value, and b* represents the yellow value.

[0064] Table 9 shows the effects of the composite quality improver on the color of sheep blood tofu

[0065] As can be seen from Table 9, after the frozen storage and high-temperature sterilization of sheep blood tofu, the color and appearance degree have all decreased to varying degrees. The color of the frozen storage is worse than that of the sterilization. After adding the composite modifier composed of elm bark gum, Artemisia sphaerocephala gum, konjac glucomannan and buckwheat flavonoids, whether it is fresh sheep blood tofu or frozen or high-temperature sterilized sheep blood tofu, the color and appearance degree have been greatly improved, indicating that this composite modifier can effectively improve the color and appearance degree of sheep blood tofu. This is because the composite modifier contains rich buckwheat flavonoids, which can effectively inhibit the oxidation and discoloration of heme, thereby improving the color and appearance degree of sheep blood tofu.

[0066] 2.5 Effect of the composite modifier on the texture of sheep blood tofu The effect of the composite modifier on the texture of sheep blood tofu is shown in Table 10.

[0067] Table 10 shows the effect of the composite quality improver on the texture of sheep blood tofu

[0068] As can be seen from Table 10, after the frozen storage and high-temperature sterilization of sheep blood tofu, texture indexes such as hardness, elasticity, cohesiveness, chewiness and resilience have all decreased significantly, and the decrease in frozen storage is greater than that of high-temperature sterilization; after adding the composite modifier composed of elm bark gum, Artemisia sphaerocephala gum, konjac glucomannan and buckwheat flavonoids, whether it is fresh sheep blood tofu or frozen or high-temperature sterilized sheep blood tofu, the texture index values have been significantly improved, indicating that this composite modifier can effectively improve the texture quality of sheep blood tofu. It may be that the composite modifier contains rich hydrophilic colloids, which can improve the water retention ability of sheep blood tofu, improve the gel properties of sheep blood tofu, make its gel structure more delicate and have higher strength.

[0069] 2.6 Effect of the composite modifier on the sensory quality of sheep blood tofu The effect of the composite modifier on the sensory quality of sheep blood tofu is shown in Table 11.

[0070] Table 11 shows the effect of the composite modifier on the sensory quality of sheep blood tofu

[0071] As can be seen from Table 11, after the frozen storage and high-temperature sterilization of sheep blood tofu, the scores of the five sensory quality indexes of smell, tissue morphology, elasticity, fineness and tenderness of the three different sheep blood tofu in the control group and the treatment group decreased significantly. The decrease in the control group was greater, and the decrease in the treatment group was relatively smaller. The scores of the five sensory indexes of the fresh sheep blood tofu, thawed sheep blood tofu and high-temperature sterilized sheep blood tofu in the treatment group were significantly higher than those in the control group, indicating that the addition of a composite modifier composed of elm bark gum, Artemisia sphaerocephala gum, konjac glucomannan and buckwheat flavonoids could effectively improve the quality of sheep blood tofu. It may be that the composite modifier contains rich hydrophilic colloids that can improve the water retention capacity of sheep blood tofu, improve the gel properties of sheep blood tofu, make its gel structure more delicate and have higher strength, resulting in better elasticity, fineness and tenderness of sheep blood tofu. This is consistent with the measurement results of the texture indexes of sheep blood tofu mentioned above, indicating again that the composite modifier can effectively improve the texture of sheep blood tofu and improve the quality of sheep blood tofu.

[0072] 3. Conclusion The research results show that adding a composite modifier composed of the water-retaining agent elm bark gum, Artemisia sphaerocephala gum and konjac glucomannan from natural plant resources and the antioxidant buckwheat flavonoids from natural plant resources to sheep blood to make sheep blood tofu can effectively inhibit the oxidative discoloration of sheep blood tofu and improve the color and appearance beauty of sheep blood tofu; the thawing loss rate and high-temperature sterilization loss rate of sheep blood tofu decreased by 26.38% and 15.45% respectively, effectively improving the water retention rate and product yield of sheep blood tofu, and also significantly improving the honeycomb structure of sheep blood tofu after thawing and high-temperature sterilization. It shows that the natural composite modifier screened in this invention has a good improvement effect on the quality of sheep blood tofu.

Claims

1. An edible blood product composite improver, characterized in that, It includes a water retainer and an antioxidant. The water retainer includes elm bark gum, artemisia sphaerocephala gum, and konjac glucomannan; the antioxidant includes buckwheat flavonoids.

2. An edible blood product composite improver according to claim 1, characterized in that Calculated by the weight ratio of the blood raw material, the water retainer contains 0.2% - 0.4% of elm bark gum, 0.2% - 0.4% of artemisia sphaerocephala gum, and 0.1% - 0.3% of konjac glucomannan; the antioxidant contains 0.2% - 0.4% of buckwheat flavonoids.

3. An edible blood product composite improver according to claim 2, characterized in that, Calculated by the weight ratio of the blood raw material, the water retainer contains 0.2% of elm bark gum, 0.3% of artemisia sphaerocephala gum, and 0.2% of konjac glucomannan; the antioxidant contains 0.3% of buckwheat flavonoids.

4. An edible blood product composite improver according to claim 1, characterized in that, The preparation of the elm bark gum is as follows: Crush dry elm bark and extract it with water. The material - liquid ratio is 1:10, the extraction temperature is 90°C - 95°C, and the extraction time is 4h - 6h. Filter to obtain the filtrate. Precipitate the filtrate with ethanol for 12h - 16h, filter, and the precipitate is vacuum freeze - dried to obtain elm bark gum.

5. The composite improver for edible blood products according to claim 1, wherein The preparation of the artemisia sphaerocephala gum is as follows: Crush dry artemisia sphaerocephala seeds and extract them with water. The material - liquid ratio is 1:8 - 1:12, the extraction temperature is 90°C - 95°C, and the extraction time is 4h - 6h. Filter to obtain the filtrate. Precipitate the filtrate with ethanol for 12h - 16h, filter, recover ethanol from the filtrate, and the obtained precipitate is vacuum freeze - dried to obtain artemisia sphaerocephala gum.

6. The composite improver for edible blood products according to claim 1, characterized in that, The preparation of the buckwheat flavonoids is as follows: Crush dry buckwheat straw and extract it with an aqueous ethanol solution at room temperature. The concentration of the aqueous ethanol solution is 75%, the material - liquid ratio is 1:8 - 1:12, the extraction time is 12h - 16h. Filter, and the filtrate is concentrated under reduced pressure to a thick paste, and then vacuum freeze - dried to obtain buckwheat flavonoids.

7. A sheep blood tofu, characterized in that, When preparing, add an edible blood product composite improver described in any one of claims 1 - 6, and the addition amount of the composite improver is calculated by the weight ratio of the sheep blood.

8. The sheep blood tofu according to claim 7, characterized in that, A coagulant is also added.

9. A method for preparing sheep blood tofu according to claim 7 or 8, characterized in that, The specific steps are as follows: Add an anticoagulant to fresh sheep blood to obtain anticoagulated sheep blood. Add a coagulant and an edible blood product composite improver described in any one of claims 1 - 6 to the anticoagulated sheep blood, stir evenly, heat, pour it into a mold, and let it stand and cool at room temperature to solidify into fresh sheep blood tofu.

10. The preparation method of a sheep blood tofu according to claim 9, characterized in that, The anticoagulant is a sodium citrate solution with a concentration of 0.5%, and the addition ratio of the sodium citrate solution to fresh sheep blood is 1:

1. The coagulant is calcium chloride, and the addition amount is 0.5% of the weight of the sheep blood.

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