Method for continuously extracting oat beta-glucan and oat starch from naked oat and application

Abstract

The invention belongs to the field of food processing, and particularly discloses a method for continuously extracting oat beta-glucan and oat starch from naked oat and application of the method, the oat beta-glucan and the oat starch are simultaneously obtained from naked oat raw materials, the production cost is effectively reduced, the utilization rate of resources is increased, and the waste of the resources is reduced; according to the method, toxic and harmful drugs are not used during extraction, so that food safety is guaranteed, and the environment is protected. Experiments prove that the yield of the oat beta-glucan extracted by the method is 40%, and the yield of the oat starch extracted by the method is 0.5%. The oat beta-glucan and the oat starch not only have common nutrition of food, but also have special functional characteristics, for example, the oat beta-glucan has the functional characteristics of reducing blood sugar, reducing blood fat, regulating immunity, benefiting gastrointestinal health and the like, and the oat starch is fine and can be widely applied to the fields of food and medicine. Therefore, the method disclosed by the invention is energy-saving and efficient, and has a wide application prospect in the aspect of preparation of oat products.

Description

Technical Field

[0001] The invention relates to the field of food processing, in particular to a method for continuously extracting oat beta-glucan and oat starch from naked oats and application thereof. Background Art

[0002] Oats belong to the genus Avena of the Poaceae family. Compared with other grains, oat starch is one of the complete nutritional foods. It has a high content of protein, essential amino acids and polyunsaturated fatty acids, and is rich in dietary fiber. Oat β-glucan is an unbranched linear polysaccharide present in the cell walls of oat aleurone, sub-aleurone and endosperm tissue. It is a water-soluble fiber. The content in oats is about 2.5%-7.8%. It is an important active ingredient in oats. It has the functional activities of lowering blood sugar, lowering cholesterol, regulating immunity, regulating gastrointestinal health, etc., and is widely used in food, health products and cosmetics. The extraction method of oat β-glucan generally adopts alkali extraction, water extraction, enzyme extraction, etc. The extraction process of oat β-glucan involves the operation of removing oat starch and protein. Oat starch accounts for about 50% to 65% of the dry weight of oat grains and is the most abundant component in oats. Oat starch not only has good functional properties such as emulsification, thickening, and water retention, but also has properties such as low thermal stability, shear resistance and high viscosity. As a new type of starch raw material, oat starch can be widely used in food, cosmetics, medicine and other fields. It would be a great waste of resources if oat starch is removed as an impurity during the extraction of oat β-glucan.

[0003] Furthermore, if oat β-glucan and oat starch can be used in the preparation of fried mushrooms, it is also possible to reduce production costs, improve the comprehensive utilization rate of resources, and effectively improve the flavor and taste of fried mushrooms. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method and application for continuously extracting oat β-glucan and oat starch from naked oats.

[0005] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0006] One of the technical solutions of the present invention is a method for continuously extracting oat β-glucan and oat starch from naked oats, comprising the following steps:

[0007] S1. Pretreatment of naked oats: After the naked oats are crushed, 85% anhydrous ethanol is added according to the solid-liquid ratio of 1g:10mL, and the naked oats are placed in a water bath at 85°C for stirring and boiling for 3h. After cooling, the mixture is filtered and the precipitate is collected. The collected precipitate is placed in a water bath to evaporate the residual anhydrous ethanol to obtain pretreated oatmeal powder;

[0008] S2, hot water extraction: deionized water was added to the pretreated oatmeal powder at a solid-liquid ratio of 1g:10mL, and the mixture was placed in a 52°C water bath for stirring and extraction for 2h, centrifuged, and the supernatant was collected; the precipitate after centrifugation was collected, hot water was added for repeated extraction for 2h, and the supernatant was collected; the two supernatants were combined to obtain a hot water extract;

[0009] S3, enzyme-assisted method for removing starch and protein: 1.5% of α-amylase by weight of the pretreated oat flour is dissolved in warm water and added to the hot water extract, and the mixture is placed in a water bath at 65°C for 2 hours to remove starch, and then 0.5% of papain by weight of the pretreated oat flour is added to the hot water extract and placed in a water bath at 65°C for 3 hours to remove protein, and the mixture is boiled at 100°C for 15 minutes to inactivate the enzyme, and then centrifuged to remove the precipitate and retain the supernatant, and the obtained supernatant is cooled and then subjected to rotary evaporation to remove the organic phase to obtain a concentrated solution;

[0010] S4, alcohol precipitation and freeze-drying to obtain crude polysaccharide: add 4 times the volume of 95% ethanol to the obtained concentrated solution and place it for 12 hours for alcohol precipitation treatment, remove the supernatant by centrifugation, collect the precipitate and re-dissolve it with an appropriate amount of water, stir it evenly with a magnetic stirrer, and freeze-dry to obtain crude polysaccharide;

[0011] S5. Purify the crude polysaccharide and freeze-dry it to obtain pure polysaccharide: add deionized water to prepare the obtained crude polysaccharide into a 5 mg / mL polysaccharide aqueous solution, add anhydrous ethanol to make its volume fraction 20% and then place it for 12 hours for alcohol precipitation, centrifuge and discard the supernatant, collect the precipitate and add appropriate amount of water to dissolve it, place it in a water bath to evaporate the residual ethanol, and freeze-dry it to obtain oat β-glucan with higher purity;

[0012] S6, slurrying, adjusting pH to extract starch: adding water to the precipitate obtained after centrifugation in step S2, homogenizing for 1 min using a homogenizer at a speed of 8000 r / min, adding edible sodium carbonate to the slurry to adjust the pH to 10, placing in a 35° C. water bath and stirring for 2 hours, centrifuging and discarding the supernatant and the brown part of the upper layer of the precipitate, and collecting the white part of the lower layer of the precipitate;

[0013] S7, washing and drying to obtain crude starch: the collected white part of the lower layer of the precipitate is placed on a 120-mesh sieve and washed with deionized water, the brown impurities in the sieve are discarded, and the washed slurry is placed in a 40° C. oven and dried for 36 hours to obtain crude starch;

[0014] S8. Enzyme-assisted purification to remove protein and dry to obtain pure starch: add 6 times the volume of deionized water to the crude starch, add 0.5% papain based on the mass of the crude starch and place it in a 45°C water bath and stir for 2 hours for enzymolysis to remove protein. After centrifugation, discard the supernatant, collect the precipitate, place the precipitate in an oven at 40°C and dry it for 36 hours, grind and crush it through an 80 mesh to obtain pure oat starch.

[0015] Preferably, in step S1, the speed of the first centrifugation after hot water extraction is 5000 r / min, and the centrifugation time is 10 min; the speed of the second centrifugation is 6000 r / min, and the centrifugation time is 13 min.

[0016] Preferably, in step S3, the centrifugal speed is 8000 r / min and the centrifugal time is 20 min.

[0017] Preferably, in step S3, the temperature of the supernatant during rotary evaporation does not exceed 60°C.

[0018] Preferably, in step S4, the rotation speed of the centrifugation after alcohol precipitation is 7000 r / min, and the centrifugation time is 10 min.

[0019] Preferably, in step S5, the rotation speed of the centrifugation after alcohol precipitation is 10000 r / min, and the centrifugation time is 20 min.

[0020] Preferably, in step S6, the centrifugal speed is 3000 r / min and the centrifugal time is 15 min.

[0021] Preferably, in step S8, the centrifugal speed is 3000 r / min and the centrifugal time is 15 min.

[0022] The second technical solution of the present invention is an application of oat β-glucan and oat starch prepared by the above method in deep-fried mushrooms, comprising:

[0023] (1) Preparation of outer paste:

[0024] The prepared oat β-glucan was added into water and stirred thoroughly, heated at 80°C for 5 minutes, quickly cooled to room temperature, and then oat starch was added and stirred thoroughly to form a paste;

[0025] (2) Wrapping:

[0026] Cut the oyster mushroom into small rectangular pieces of 1 cm × 3 cm × 5 mm, and put them into the outer coating paste prepared in step (1);

[0027] (3) Deep frying:

[0028] Preheat the oil pan to 160°C, put the mushroom pieces coated with batter into the oil pan and fry for 6 minutes, then take them out and cool to room temperature to obtain fried mushrooms.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention can obtain oat β-glucan and oat starch from a naked oat raw material, effectively reducing production costs, improving resource utilization, and reducing resource waste; the present invention does not use toxic and harmful drugs in the extraction, which not only ensures food safety but also protects the environment. Experiments have shown that the yields of oat β-glucan and oat starch extracted by the method of the present invention are 40% and 0.5%, respectively. In addition to the usual nutrients of food, oat β-glucan and oat starch also have special functional properties. For example, oat β-glucan has the functional properties of lowering blood sugar, lowering blood lipids, regulating immunity, and benefiting gastrointestinal health. Oat starch is delicate and can be widely used in the fields of food and medicine. Therefore, the method of the present invention is energy-saving and efficient, and has broad application prospects in the preparation of oat products.

[0031] 2. The composite system of oat starch and oat β-glucan extracted by the present invention is applied to fried mushrooms to effectively improve the crispy taste of fried mushrooms, produce a richer aroma, increase the powder coating rate during the production process of fried mushrooms, reduce the mass loss rate during frying, reduce the oil migration rate, make the fried mushrooms more chewy and have a more elastic taste, and improve the brightness of the fried mushroom samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the molecular weight distribution diagram of oat β-glucan extracted in Example 1.

[0033] Figure 2 This is the infrared spectrum of the oat starch extracted in Example 1.

[0034] Figure 3 This is the molecular weight distribution diagram of the oat starch extracted in Example 1.

[0035] Figure 4 This is the X-ray diffraction pattern of the oat starch extracted in Example 1.

[0036] Figure 5 This is the polarized cross diagram of the oat starch extracted in Example 1.

[0037] Figure 6 This is a scanning electron microscope image of the oat starch extracted in Example 1. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0039] Example 1

[0040] (1) Pre-treatment of naked oats:

[0041] The naked oats were crushed into oatmeal powder, 200 g of naked oatmeal powder was weighed, and the powder was placed in 2000 mL of 85% ethanol and boiled in a water bath at 85°C for 3 h, and then filtered after cooling to collect the precipitate, and the collected precipitate was placed in a water bath to evaporate the residual anhydrous ethanol to obtain a pretreated product;

[0042] (2) Hot water extraction:

[0043] Weigh 180 g of the pretreated product after removing ethanol, add 1800 mL of deionized water and place in a 52°C water bath for stirring and leaching for 2 h, then centrifuge at 5000 r / min for 10 min and collect the supernatant, collect the precipitate after centrifugation, add 1800 mL of deionized water and extract at 52°C for 2 h, then centrifuge at 6000 r / min for 13 min and collect the supernatant, combine it with the first supernatant, and collect the precipitate for later use;

[0044] (3) Enzymatic removal of starch and protein:

[0045] 1.5% of the mass of the pre-treatment product of the hot water soaking is dissolved with an appropriate amount of warm water, added to the supernatant of the two times combined, and the mixture is placed in a water bath at 65°C for 2 hours to remove starch, and then 0.5% of the mass of the pre-treatment product of the hot water soaking is added to the supernatant and the mixture is placed in a water bath at 65°C for 3 hours to remove protein, and then the mixture is boiled at 100°C for 15 minutes to inactivate the enzyme, and then centrifuged at a speed of 8000 r / min for 20 minutes to remove the precipitate and retain the supernatant, and the obtained supernatant is cooled and then the organic phase is removed by rotary evaporation at 58°C to obtain a concentrated solution;

[0046] (4) Alcohol precipitation and freeze-drying to obtain crude polysaccharide:

[0047] Take 50 mL of the concentrate, add 200 mL of 95% ethanol to the concentrate for alcohol precipitation, then centrifuge at 7000 r / min for 10 min, remove the supernatant, collect the precipitate and re-dissolve it with an appropriate amount of water, stir it evenly with a magnetic stirrer, and freeze-dry to obtain crude polysaccharide;

[0048] (5) Purification of crude polysaccharide followed by freeze-drying to obtain pure polysaccharide:

[0049] The freeze-dried sample was prepared into a 5 mg / mL polysaccharide solution, anhydrous ethanol was added to precipitate it to a volume fraction of 20%, and then it was placed for 12 hours for alcohol precipitation. After centrifugation at a speed of 1000 r / min for 20 minutes, the supernatant was discarded, the precipitate was collected and dissolved in an appropriate amount of water, and the residual ethanol was evaporated in a water bath, and freeze-dried to obtain oat β-glucan with higher purity;

[0050] (6) Pulping, adjusting pH and extracting starch:

[0051] Add an appropriate amount of water to the precipitate obtained after centrifugation in step (2), homogenize it with a homogenizer at a speed of 8000 r / min for 1 min, add edible sodium carbonate to the slurry to adjust the pH to 10, put it in a 35°C water bath and stir for 2 hours, centrifuge it at a speed of 3000 r / min for 15 min, discard the supernatant and the brown part of the upper layer of the precipitate, and collect the white part of the lower layer of the precipitate;

[0052] (7) washing and drying to obtain crude starch:

[0053] The collected white part was placed on a 120-mesh sieve and washed with deionized water, and the brown impurities in the sieve were discarded. The washed slurry was placed in an oven at 40°C and dried for 36 hours to obtain crude starch;

[0054] (8) Enzyme-assisted purification to remove protein and dry to obtain pure starch:

[0055] Take 50g of crude starch, add 300mL of deionized water and 5mg / mL of papain, place it in a 45℃ water bath and stir for 2h for enzymolysis to remove protein, centrifuge at 3000r / min for 15min, discard the supernatant, wash it with deionized water in a 120-mesh sieve, collect the precipitate, dry it in a 40℃ oven for 48h, grind the dried powder through an 80-mesh sieve to obtain pure oat starch;

[0056] Figure 1 The molecular weight distribution diagram of oat β-glucan extracted in Example 1 is shown in FIG. Figure 1 It can be seen that the molecular weight dispersion coefficient of the oat β-glucan extracted in Example 1 is small, indicating that its uniformity is good. Figure 1 The infrared spectrum of oat starch extracted in Example 1 is shown in FIG. Figure 2 It can be seen that the infrared spectrum of the oat starch prepared in Example 1 is a typical infrared spectrum of starch, including absorption peaks of the skeleton vibration of the asymmetric ring mode of starch, the stretching vibration of the CC bond and the CO bond, the skeleton mode vibration of starch, etc. Figure 3 The molecular weight distribution diagram of the oat starch extracted in Example 1 is shown in FIG. Figure 3 It can be seen that the dispersion coefficient of oat starch is small, indicating that the distribution of oat starch is uniform. Figure 4 The X-ray diffraction pattern of oat starch extracted in Example 1 is shown in FIG. Figure 4 It can be seen that characteristic peaks appear at around 18°, 20°, and 23°, indicating that oat starch is a typical A-type starch. Figure 5 This is the polarized cross diagram of the oat starch extracted in Example 1. Figure 5 It can be seen that oat starch presents a typical and clear polarization cross, indicating that oat starch has an ordered and complete granular structure. Figure 6 This is a scanning electron microscope image of the oat starch extracted in Example 1. Figure 6 It can be seen that oat starch particles are small, irregular in shape, with different particle sizes, and the particles are angular or oval.

[0057] 1. Component identification rate test of two products

[0058] (1) Oat β-glucan

[0059] Test methods for the content and characteristics of oat β-glucan components: the moisture content shall be determined in accordance with GB 5009.3-2016 National Food Safety Standard for the Determination of Moisture in Foods; the ash content shall be determined in accordance with GB 5009.4-2016 National Food Safety Standard for the Determination of Ash in Foods; the total sugar content shall be determined by the phenol-sulfuric acid method, the total phenol content shall be determined by the folin phenol method, the protein content shall be determined by the Coomassie Brilliant Blue method, the uronic acid content shall be determined by the carbazole sulfate method, the reducing sugar content shall be determined by the 3,5-dinitrosalicylic acid method, and the β-glucose content shall be determined by the Congo red staining method.

[0060] Oat β-glucan extraction rate calculation formula:

[0061]

[0062] Results: The extraction rate of oat β-glucan was 0.5%. The moisture content was (7.81±0.05) g / 100g, the ash content was 10.94 g / 100g, the total sugar content was (71.94 g±1.18) g / 100g, the total phenol content was (1.06 g±0.02) g / 100g, the protein content was (4.91 g±0.07) g / 100g, the uronic acid content was (2.64±0.04) g / 100g, the reducing sugar content was (7.45 g±0.23) g / 100g, and the β-glucan content was (52.77 g±0.10) g / 100g.

[0063] (2) Oat starch

[0064] Test methods for the content and characteristics of oat starch components: the moisture content shall be determined in accordance with GB5009.3-2016 National Food Safety Standard for the Determination of Moisture in Foods; the ash content shall be determined in accordance with GB5009.4-2016 National Food Safety Standard for the Determination of Ash in Foods; the protein content shall be determined by the Coomassie Brilliant Blue method; the fat content shall be determined in accordance with GB 5009.6-2016 National Food Safety Standard for the Determination of Fat in Foods; and the starch content shall be determined using a starch content detection kit.

[0065] Oat starch extraction rate calculation formula:

[0066]

[0067] Results: The extraction rate of oat starch was 38%. The obtained oat starch was a pure white, fine powder with natural oat flavor. The moisture content, ash content, residual protein content, fat content and starch content of the oat starch were (0.27±0.02) g / 100g, (0.28±0.23) g / 100g, (0.03±0.02) g / 100g, (0.72±0.04) g / 100g and (86g±7.21) g / 100g, respectively.

[0068] Application Example 1

[0069] (1) Preparation of outer paste (compound system):

[0070] The oat β-glucan prepared in Example 1 was added into water and stirred thoroughly, heated at 80° C. for 5 min, and rapidly cooled to room temperature. The oat starch extracted in Example 1 was then added and stirred thoroughly to form a paste.

[0071] (2) Wrapping:

[0072] Cut the oyster mushroom into small rectangular pieces of 1 cm×3 cm×5 mm, and put them into the outer coating batter prepared in step (1).

[0073] (3) Deep frying:

[0074] The oil pan was preheated at 160° C., the mushroom pieces coated with the paste were put into the oil pan and fried for 6 minutes, then taken out and cooled to room temperature to obtain fried mushrooms (OS-OBG) prepared with a composite system of oat starch and oat β-glucan as the outer coating paste.

[0075] Application Comparative Example 1

[0076] (1) Preparation of outer paste (compound system):

[0077] The oat β-glucan prepared in Example 1 was added to water and stirred thoroughly, heated at 80° C. for 5 min, quickly cooled to room temperature, and then commercially available corn starch was added and stirred thoroughly to form a paste.

[0078] (2) Wrapping:

[0079] Cut the oyster mushroom into small rectangular pieces of 1 cm×3 cm×5 mm, and put them into the outer coating batter prepared in step (1).

[0080] (3) Deep frying:

[0081] The oil pan was preheated at 160° C., the mushroom pieces coated with the paste were put into the oil pan and fried for 6 minutes, then taken out and cooled to room temperature to obtain fried mushrooms (CS-OBG) prepared with a composite system of corn starch and oat β-glucan as the outer coating paste.

[0082] Application Comparative Example 2

[0083] (1) Preparation of outer paste (compound system):

[0084] The oat starch prepared in Example 1 was added into water and stirred thoroughly to form a paste.

[0085] (2) Wrapping:

[0086] Cut the oyster mushroom into small rectangular pieces of 1 cm×3 cm×5 mm, and put them into the outer coating batter prepared in step (1).

[0087] (3) Deep frying:

[0088] The oil pan was preheated at 160° C., the mushroom pieces coated with the paste were put into the oil pan and fried for 6 minutes, then taken out and cooled to room temperature to obtain fried mushrooms (OS) prepared with oat starch as the outer coating paste.

[0089] Application Comparative Example 3

[0090] (1) Preparation of outer paste (compound system):

[0091] Add commercially available corn starch to water and stir thoroughly to make a paste.

[0092] (2) Wrapping:

[0093] Cut the oyster mushroom into small rectangular pieces of 1 cm×3 cm×5 mm, and put them into the outer coating batter prepared in step (1).

[0094] (3) Deep frying:

[0095] The oil pan was preheated at 160° C., the mushroom pieces coated with the paste were put into the oil pan and fried for 6 min, then taken out and cooled to room temperature to obtain fried mushrooms (CS) prepared with corn starch as the outer coating paste.

[0096] (5) The effect of oat starch / oat β-glucan complex system as a coating in fried food was evaluated by constructing a fried mushroom model and exploring its physicochemical properties during the preparation process and the finished product. The physicochemical property characterization of the above model includes the following steps:

[0097] The moisture content of fried mushrooms was determined in accordance with GB5009.3-2016 National Food Safety Standard for the Determination of Moisture in Food. The results of the moisture content of four types of fried mushrooms are shown in Table 1.

[0098] Table 1 Comparison of moisture content of four fried mushrooms

[0099]

[0100] Note: The results are expressed as the mean ± standard deviation of three parallel experiments. Different letters indicate significant differences (P < 0.05).

[0101] The fat content was determined in accordance with GB5009.6-2016 National Food Safety Standard for the Determination of Fat in Food. The moisture content of the four fried mushrooms is shown in Table 2.

[0102] Table 2 Comparison of fat content of four fried mushrooms

[0103]

[0104] Note: The results are expressed as the mean ± standard deviation of three parallel experiments. Different letters indicate significant differences (P < 0.05).

[0105] Effect of oat β-glucan / oat starch complex system as fried mushroom coating on the oil migration rate of fried mushrooms: Prepare a petri dish with 5 layers of oil-absorbing paper and measure its initial total weight, recorded as m0. Place a portion of fried mushrooms with a known mass of m1 in the petri dish and place it in a constant temperature environment of 30°C for 24 hours. Take out the petri dish and measure the total weight including the oil-absorbing paper and any migrated oil, recorded as m2. Calculate the oil migration rate according to the following formula:

[0106]

[0107] The results of oil migration rate determination of four fried mushrooms are shown in Table 3.

[0108] Table 3 Comparison of oil migration rates of four fried mushrooms

[0109]

[0110] Note: The results are expressed as the mean ± standard deviation of three parallel experiments. Different letters indicate significant differences (P < 0.05).

[0111] The effect of oat β-glucan / oat starch compound system as fried mushroom coating powder on the coating rate of fried mushrooms: calculated according to the following formula:

[0112]

[0113] The results of battering rate determination of four kinds of fried mushrooms are shown in Table 4.

[0114] Table 4 Comparison of batter coating rates of four fried mushrooms

[0115]

[0116] Note: The results are expressed as the mean ± standard deviation of three parallel experiments. Different letters indicate significant differences (P < 0.05).

[0117] The effect of oat β-glucan / oat starch compound system as fried mushroom breading on the weight loss rate of fried mushrooms: calculated according to the following formula:

[0118]

[0119] The results of frying weight loss rate of four fried mushrooms are shown in Table 5.

[0120] Table 5 Comparison of frying weight loss rate of four fried mushrooms

[0121]

[0122] Note: The results are expressed as the mean ± standard deviation of three parallel experiments. Different letters indicate significant differences (P < 0.05).

[0123] Effect of oat β-glucan / oat starch composite system as fried mushroom coating on the texture of fried mushroom core: The fried mushrooms were cooled at room temperature, and after removing the outer coating, the texture of the inner core mushrooms was measured. The results are shown in Table 6.

[0124] Table 6 Comparison of the texture of four kinds of fried mushroom cores

[0125] sample Hardness / g Elasticity / mm Chewability / N Adhesion / g Cohesion OS-OBG <![CDATA[597.43±39.41 b ]]> <![CDATA[2.65±0.06 b ]]> <![CDATA[11.88±0.52 a ]]> <![CDATA[456.4±20.24 a ]]> <![CDATA[0.72±0.03 b ]]> CS-OBG <![CDATA[432±7.41 d ]]> <![CDATA[2.23±0.11 cd ]]> <![CDATA[8.24±0.11 c ]]> <![CDATA[380.43±4.80 b ]]> <![CDATA[0.86±0.02 a ]]> OS <![CDATA[485.8±17.52 c ]]> <![CDATA[2.33±0.16 c ]]> <![CDATA[8.56±0.50 c ]]> <![CDATA[364.3±22.57 b ]]> <![CDATA[0.72±0.04 b ]]> CS <![CDATA[245.77±5.05 f ]]> <![CDATA[1.73±0.10 e ]]> <![CDATA[2.97±0.18 d ]]> <![CDATA[175.83±11.27 d ]]> <![CDATA[0.7±0.03 b ]]>

[0126] Note: The results are expressed as the mean ± standard deviation of three parallel experiments. Different letters indicate significant differences (P < 0.05).

[0127] Effect of oat β-glucan / oat starch complex system as fried mushroom coating powder on sensory evaluation of fried mushrooms: 10 students (including 5 boys and 5 girls) who have undergone sensory evaluation training were selected to conduct sensory evaluation of fried mushrooms. The evaluation items included 5 indicators such as color and smell. The specific evaluation process is: about 20 grams of fried mushroom samples are placed on a disposable white paper plate marked with a double-digit code to ensure the blindness of the evaluation. After trying each sample, the evaluation team members need to rinse their mouths with mineral water and rest for about 1 minute. The evaluation of each sample should be completed within 1 minute, and the evaluation process of the entire group of samples should be completed within 20 minutes. The sensory evaluation table is shown in Table 7, and the sensory evaluation results of the four fried mushrooms are shown in Table 8.

[0128] Table 7 Sensory evaluation table

[0129]

[0130] Table 8 Comparison of sensory evaluation results of four fried mushrooms

[0131]

[0132] Note: The results are expressed as the mean ± standard deviation of three parallel experiments. Different letters indicate significant differences (P < 0.05).

[0133] The above results show that since oat β-glucan has high viscosity, gelation and strong hydration capacity, oat starch has high fiber content and good water absorption, and oat starch and oat β-glucan are connected by hydrogen bonds to form a stable three-dimensional gel network structure, which helps to improve the stability of the outer batter layer of fried mushrooms, reduce the weight loss rate during frying, reduce the oil migration rate, increase the elasticity and chewiness of fried mushrooms, reduce the moisture content of fried mushrooms, and thus extend the shelf life of fried mushrooms.

[0134] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A method for continuously extracting oat β-glucan and oat starch from naked oats, characterized in that: The following steps are involved: S1. Pretreatment of naked oats: After the naked oats are crushed, 85% anhydrous ethanol is added according to the solid-liquid ratio of 1g:10mL, and the naked oats are placed in a water bath at 85°C for stirring and boiling for 3h. After cooling, the mixture is filtered and the precipitate is collected. The collected precipitate is placed in a water bath to evaporate the residual anhydrous ethanol to obtain pretreated oatmeal powder; S2, hot water extraction: deionized water was added to the pretreated oatmeal powder at a solid-liquid ratio of 1 g:10 mL and the mixture was placed in a 52°C water bath for stirring and extraction for 2 h, and the supernatant was collected after centrifugation; Collect the precipitate after centrifugation, add hot water and extract repeatedly for 2 hours, then centrifuge and collect the supernatant; combine the two supernatants to obtain a hot water extract; S3, enzyme-assisted method for removing starch and protein: 1.5% of α-amylase by weight of the pretreated oat flour is dissolved in warm water and added to the hot water extract, and the mixture is placed in a water bath at 65°C for 2 hours to remove starch, and then 0.5% of papain by weight of the pretreated oat flour is added to the hot water extract and placed in a water bath at 65°C for 3 hours to remove protein, and the mixture is boiled at 100°C for 15 minutes to inactivate the enzyme, and then centrifuged to remove the precipitate and retain the supernatant, and the obtained supernatant is cooled and then subjected to rotary evaporation to remove the organic phase to obtain a concentrated solution; S4, alcohol precipitation and freeze-drying to obtain crude polysaccharide: add 4 times the volume of 95% ethanol to the obtained concentrated solution and place it for 12 hours for alcohol precipitation treatment, remove the supernatant by centrifugation, collect the precipitate and re-dissolve it with an appropriate amount of water, stir it evenly with a magnetic stirrer, and freeze-dry to obtain crude polysaccharide; S5. Purify the crude polysaccharide and freeze-dry it to obtain pure polysaccharide: add deionized water to prepare the obtained crude polysaccharide into a 5 mg / mL polysaccharide aqueous solution, add anhydrous ethanol to make its volume fraction 20% and then place it for 12 hours for alcohol precipitation, centrifuge and discard the supernatant, collect the precipitate and add appropriate amount of water to dissolve it, place it in a water bath to evaporate the residual ethanol, and freeze-dry it to obtain oat β-glucan with higher purity; S6, slurrying, adjusting pH to extract starch: adding water to the precipitate obtained after centrifugation in step S2, homogenizing for 1 min using a homogenizer at a speed of 8000 r / min, adding edible sodium carbonate to the slurry to adjust the pH to 10, placing in a 35° C. water bath and stirring for 2 hours, centrifuging and discarding the supernatant and the brown part of the upper layer of the precipitate, and collecting the white part of the lower layer of the precipitate; S7, washing and drying to obtain crude starch: the collected white part of the lower layer of the precipitate is placed on a 120-mesh sieve and washed with deionized water, the brown impurities in the sieve are discarded, and the washed slurry is placed in a 40° C. oven and dried for 36 hours to obtain crude starch; S8. Enzyme-assisted purification to remove protein and dry to obtain pure starch: add 6 times the volume of deionized water to the crude starch, add 0.5% papain based on the mass of the crude starch and place it in a 45°C water bath and stir for 2 hours for enzymolysis to remove protein. After centrifugation, discard the supernatant, collect the precipitate, place the precipitate in an oven at 40°C and dry it for 36 hours, grind and crush it through an 80 mesh to obtain pure oat starch.

2. The method for continuously extracting oat β-glucan and oat starch from naked oats according to claim 1, characterized in that: In the step S1, the speed of the first centrifugation after hot water extraction is 5000 r / min, and the centrifugation time is 10 min; the speed of the second centrifugation is 6000 r / min, and the centrifugation time is 13 min.

3. The method for continuously extracting oat β-glucan and oat starch from naked oats according to claim 1, characterized in that: In step S3, the centrifugal speed is 8000 r / min and the centrifugal time is 20 min.

4. The method for continuously extracting oat β-glucan and oat starch from naked oats according to claim 1, characterized in that: In step S3, the temperature of the supernatant during rotary evaporation does not exceed 60°C.

5. The method for continuously extracting oat β-glucan and oat starch from naked oats according to claim 1, characterized in that: In the step S4, the centrifugal speed after alcohol precipitation is 7000 r / min, and the centrifugal time is 10 min.

6. The method for continuously extracting oat β-glucan and oat starch from naked oats according to claim 1, characterized in that: In the step S5, the rotation speed of the centrifuge after alcohol precipitation is 10000 r / min, and the centrifugation time is 20 min.

7. The method for continuously extracting oat β-glucan and oat starch from naked oats according to claim 1, characterized in that: In step S6, the centrifugal speed is 3000 r / min and the centrifugal time is 15 min.

8. The method for continuously extracting oat β-glucan and oat starch from naked oats according to claim 1, characterized in that: In step S8, the centrifugal speed is 3000 r / min and the centrifugal time is 15 min.

9. Use of oat β-glucan and oat starch prepared by the method according to claim 1 in deep-frying mushrooms.

10. The use according to claim 9, characterized in that: include: (1) Preparation of outer paste: The prepared oat β-glucan was added into water and stirred thoroughly, heated at 80°C for 5 minutes, quickly cooled to room temperature, and then oat starch was added and stirred thoroughly to form a paste; (2) Wrapping: Cut the oyster mushroom into small rectangular pieces of 1 cm×3 cm×5 mm, and put them into the outer coating paste prepared in step (1); (3) Deep frying: Preheat the oil pan to 160°C, put the mushroom pieces coated with batter into the oil pan and fry for 6 minutes, then take them out and cool to room temperature to obtain fried mushrooms.

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