A secale cereale pollen peptide calcium chelate and a preparation method and application thereof

Abstract

The application discloses a preparation method of rye pollen peptide calcium chelate, which comprises the following steps: raw material wall breaking and defatting treatment; protein extraction: mixing pretreated rye pollen with distilled water, adjusting the pH value of the system to 10-11, and treating at 55-60 DEG C for 1.5-2 h; after filtering and separating to obtain supernatant, the pH value of the system is adjusted to 4.0-4.5, the precipitate is filtered, and the precipitate is washed to neutral and dried to obtain rye pollen protein; rye pollen peptide calcium chelate preparation: enzymolysis, namely mixing rye pollen and distilled water at a ratio of 1:15-1:25, adjusting the pH of the system to 7-9 by using calcium hydroxide solution, adding protease at a temperature of 45-55 DEG C, reacting for 2-4 h, and then inactivating the enzyme at a temperature of 90 DEG C for 10-15 min; then, after the temperature of the system is reduced to 50 DEG C, carbon dioxide is introduced to prepare the rye pollen peptide calcium chelate; and the method has low production cost and simple process. The rye pollen peptide calcium chelate is applied in frozen dough to improve the anti-freezing capacity of the dough.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of food processing, in particular to a rye pollen peptide calcium chelate and a preparation method and application thereof. BACKGROUND

[0002] Pollen is a small spore sac of small spore leaves of gymnosperms or a granular male microgametophyte produced by anthers of stamens of angiosperms, which contains rich nutrients such as proteins, amino acids, polysaccharides, flavones, unsaturated fatty acids, trace elements, vitamins, and enzymes, and is a natural nutrient for maintaining human nutritional balance. Many pollens have been widely developed and utilized at home and abroad on the basis of effectiveness and safety. The components of pollens such as pine pollen, rape pollen, and buckwheat pollen have been confirmed to have multiple activities such as enhancing the body's immunity, antioxidant, anti-fatigue, regulating the endocrine system and nervous system function, etc. There are also many pollen raw materials in China, such as rape pollen, corn pollen, and pine pollen, which have been identified as ordinary food raw materials. With the continuous exploration of new resource foods, the development of functional foods using pollen as raw materials will be a new research hotspot in the future.

[0003] Rye pollen is collected from rye pollen and processed by drying and separation, which has a positive effect on prostate health, liver health, female menopausal health, and immune health. The protein content in pollen is high, but as a macromolecule, it cannot be directly absorbed by the human body. The protein ingested by humans is mainly in the form of short peptides. If the protein in the pollen is processed to reduce its molecular weight, it is of great significance to improve the nutritional value and functional characteristics of the pollen and efficiently utilize plant protein resources.

[0004] With the gradual improvement of national health awareness today, dietary nutrition supplementation is the mainstream. At the same time, a large number of health products rich in functional ingredients and beneficial to the human body have emerged in the market. As we all know, calcium is the most abundant inorganic element in the human body, and insufficient calcium intake will lead to the occurrence of diseases such as osteoporosis, rickets, and osteomalacia. With the intensification of global aging, the number of patients with osteoporosis is increasing year by year, which is called "silent epidemic" by the World Health Organization. The only way to obtain calcium in the skeleton is through dietary intake, and the most common form of calcium intake through diet is ionic calcium (mainly calcium carbonate and calcium gluconate, etc.). Although the calcium content of calcium supplements on the market is high, the amount that can be absorbed by the human body is very limited. It is currently believed that calcium in the form of chelate has higher bioavailability and lower biological toxicity than ionic calcium, and has been more widely studied and concerned. Protein hydrolysates have the ability to chelate calcium and can be used as raw materials for the production of calcium supplements, which has been widely recognized.

[0005] On the other hand, the frozen dough technology is a new bread production process developed in the 1950s, and its application in many countries and regions in Europe and America is quite popular. The quality deterioration of frozen dough is caused by the deterioration of key components of the dough due to ice recrystallization, among which the destruction of gluten protein is an important reason for the decrease in volume, the increase in hardness and the shortening of shelf life of the baked goods produced from frozen dough. Therefore, developing new technical means or raw materials to improve the above-mentioned problems of frozen dough is of great importance to the development of the frozen dough industry.

[0006] The existing method for preparing rye pollen peptide calcium chelate mainly includes the following steps: first, preparing a protein hydrolysate by enzymolysis or fermentation method, then obtaining a peptide by neutralization and filtration, and then performing a chelation reaction with calcium ions. The process is relatively complex.

[0007] To improve the above-mentioned problems, the present application provides a new method for preparing rye pollen peptide calcium chelate, and applies it to the preparation of frozen dough. SUMMARY

[0008] The present application aims to provide a method for preparing rye pollen peptide calcium chelate, which has the advantages of low production cost, simple process, and high yield of rye pollen peptide calcium chelate. In addition, the product prepared is applied to frozen dough, which can enhance the gluten strength and improve the freezing resistance of the dough.

[0009] To achieve the above-mentioned purpose, the solution of the present application is as follows: a method for preparing rye pollen peptide calcium chelate, comprising the following steps:

[0010] (1) Raw material pretreatment: breaking the wall and removing the fat of rye pollen;

[0011] (2) Protein extraction: extracting protein by alkali extraction and acid precipitation, mixing the pretreated rye pollen with distilled water at a ratio of 1:10-1:20, adjusting the pH value of the system to 10-11, performing ultrahigh pressure treatment for 10 min, and then treating at 55-60℃ for 1.5-2 h; filtering to separate the supernatant, adjusting the pH value of the system to 4.0-4.5, filtering again to obtain a precipitate, washing the precipitate to neutral, and drying to obtain rye pollen protein for standby use;

[0012] (3) Preparation of rye pollen peptide calcium chelate: first, enzymolysis of rye pollen protein, i.e. mixing rye pollen with distilled water at a ratio of 1:15-1:25, adjusting the pH value of the system to 7-9 using calcium hydroxide solution, and keeping the reaction temperature at 45-55℃; adding protease during the reaction; after 2-4 h of reaction, inactivating the enzyme at 90℃ for 10-15 min; then, when the temperature of the system drops to 50℃, pass in carbon dioxide, and by controlling the molar mass ratio of calcium hydroxide to carbon dioxide, rye pollen peptide calcium chelate is prepared.

[0013] Further, in the step (1) raw material pretreatment, the rye pollen is mixed with 75wt% ethanol at a ratio of 1:25, and placed in an ultrasonic reactor for double-frequency ultrasonic treatment, with an ultrasonic frequency of 20 / 40 kHz and a treatment time of 30 min.

[0014] Further, in the step (2), the pH value of the system is first adjusted to 10-11 using a sodium hydroxide solution, and then adjusted to 4.0-4.5 using a hydrochloric acid solution.

[0015] Further, in the step (3), the rye pollen is mixed with distilled water and then put into a bubble reactor for reaction.

[0016] Further, in the step (3), the protease is one or more of alkaline protease, acid protease or bromelain.

[0017] Further, in the step (3), the mass ratio of each protease is as follows: the mass of alkaline protease accounts for 0.5%-3% of the mass of rye pollen protein; the mass of acid protease accounts for 1%-2% of the mass of rye pollen protein; and the mass of bromelain accounts for 0.25%-0.5% of the mass of rye pollen protein.

[0018] Further, in the step (3), the molar mass ratio of the introduced carbon dioxide to calcium hydroxide is 0.5:1-1:0.75.

[0019] Further, in the step (3), after introducing carbon dioxide into the system in a certain proportion, the system is allowed to stand, filtered, and the supernatant is dried to obtain rye pollen peptide calcium chelate, which is rye pollen peptide calcium powder.

[0020] Another object of the present application is to provide a rye pollen peptide calcium chelate.

[0021] To achieve the above object, the solution of the present application is a rye pollen peptide calcium chelate prepared by the above preparation method.

[0022] Still another object of the present application is to provide the application of the rye pollen peptide calcium chelate in frozen dough.

[0023] In order to achieve the above-mentioned purpose, the application provides the application of rye pollen peptide calcium chelate in frozen dough, the rye pollen peptide calcium chelate is compounded with high-gluten wheat flour at a ratio of 0.1%-1%:100%, sodium alginate is added (0%-1% of the weight of the flour), and then mixed uniformly, water is added (55% of the weight of the flour), and then mixed, and finally the dough is placed in a-80 DEG C refrigerator until the temperature of the center of the dough is-18 DEG C, and then the dough is stored in a-18 DEG C refrigerator, so as to obtain the frozen dough.

[0024] After the above scheme is adopted, the application has the following beneficial effects:

[0025] 1. The application adopts a one-step method to prepare the rye pollen peptide calcium chelate, that is, Ca(OH)2 is used as a pH regulator of the system and as a raw material for increasing the calcium source, that is, calcium ions are introduced in the process of enzymatic hydrolysis of the protein, and finally the rye pollen peptide calcium chelate is formed. At present, the method for preparing the rye pollen peptide calcium chelate mainly includes the following steps: first, a protein hydrolysate is prepared by an enzymatic hydrolysis method (the mainstream method is to use a strong alkali (mainly NaOH) to adjust the pH of the system in the enzyme preparation) or a fermentation method, then the pH of the system is neutralized (mainly by using a strong acid, mainly HCl), and then the peptide is obtained by filtration, and then the peptide is further chelated with a calcium ion-containing substance (mainly CaCl2), and finally the process is relatively complex.

[0026] 2. The application provides a method for preparing rye pollen peptide or rye pollen peptide calcium chelate, which has the advantages of low production cost, simple process, high yield of rye pollen peptide calcium chelate, and good application prospect.

[0027] 3. The application also provides the application of the rye pollen peptide calcium chelate prepared by the above method in frozen dough, which can enhance the gluten strength and improve the anti-freezing capacity of the dough. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Fig. 1 is a graph showing the influence of the ultrasonic / pollen concentration ratio on the protein extraction rate according to an embodiment of the application;

[0029] Figure 2 Fig. 2 is a graph showing the influence of the change of the pH of the system on the yield of the rye pollen calcium peptide chelate according to an embodiment of the application;

[0030] Figure 3 Fig. 3 is a graph showing the influence of the amount of carbon dioxide introduced on the yield of the rye pollen calcium peptide chelate according to an embodiment of the application;

[0031] Figure 4 Fig. 4 is an infrared spectrum of rye pollen, rye pollen protein and rye pollen peptide according to an embodiment of the application;

[0032] Figure 5 is a microstructure diagram of dough provided according to an embodiment of the present application;

[0033] Figure 6 is an influence of reaction device change on rye pollen peptide calcium chelate yield provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] The present application is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] Example 1: Preparation of rye pollen peptide calcium chelate.

[0036] (1) Raw material pretreatment: The rye pollen was subjected to wall breaking and defatting treatment, and the specific operation was as follows: the rye pollen was mixed with 75wt% ethanol at a ratio of 1:25, and placed in an ultrasonic reactor for double-frequency ultrasonic treatment, with an ultrasonic frequency of 20 / 40 kHz and a treatment time of 30 min.

[0037] (2) Protein extraction: The protein was extracted by the method of alkali extraction and acid precipitation, the pretreated rye pollen was mixed with distilled water at a ratio of 1:10-1:20, and the pH value of the system was adjusted to 10-11 using sodium hydroxide solution under stirring, and then subjected to ultrahigh pressure treatment for 10 min (300 MPa) and treated at 55-60°C for 1.5-2 h; after filtration, the supernatant was separated, the pH value of the system was adjusted to 4.0-4.5 using hydrochloric acid solution, and the precipitate was obtained after filtration again, and then washed to neutral and dried to obtain rye pollen protein for standby.

[0038] (3) Preparation of rye pollen peptide calcium chelate: The rye pollen protein was first subjected to enzymatic hydrolysis, i.e., the rye pollen was mixed with distilled water at a ratio of 1:15-1:25, and then put into a bubble reactor, and the pH value of the system was adjusted to 7-9 using calcium hydroxide solution, and the reaction temperature was maintained at 45-55°C;

[0039] One or more of alkaline protease, acid protease or bromelain was added in sequence during the preparation process, and the mass ratio of each protease was as follows: the mass of alkaline protease accounted for 0.5%-3% of the mass of rye pollen protein; the mass of acid protease accounted for 1%-2% of the mass of rye pollen protein; the mass of bromelain accounted for 0.25%-0.5% of the mass of rye pollen protein;

[0040] After 2-4 h of reaction, the temperature of the system was raised to 90°C for 15 min for enzyme inactivation treatment; then, after the temperature of the system was lowered to 50°C, carbon dioxide was introduced, and the molar mass ratio of the introduced carbon dioxide to calcium hydroxide was 0.75:1 or 1:1, and after standing for 30 min, the supernatant was filtered and dried to collect rye pollen peptide calcium powder.

[0041] The following is a single factor analysis of the reaction conditions in the preparation of rye pollen protein and rye pollen peptide calcium chelate, including ultrasonic conditions, pH value, type and amount of enzyme added, CO2 flow rate, and reactor.

[0042] Example 2: Effect of ultrasonic and solid-liquid ratio on preparation of rye pollen protein.

[0043] (1) Raw material pretreatment: The rye pollen was subjected to wall breaking and degreasing treatment, and the specific operation was as follows: the rye pollen was mixed with 75wt% ethanol at a ratio of 1:25, and placed in an ultrasonic reactor for double-frequency ultrasonic treatment, with an ultrasonic frequency of 20 / 40 kHz and a treatment time of 30 min.

[0044] (2) Protein extraction: The pretreated rye pollen was mixed with distilled water at a ratio of 1:10 to 1:20, and the pH value of the system was adjusted to 11 using sodium hydroxide solution under stirring. After ultrahigh pressure treatment for 10 min (300 MPa), the system was treated at 55°C for 2 h. After filtration to separate the supernatant, the pH value of the system was adjusted to 4.0 using hydrochloric acid solution, and the precipitate was obtained after filtration again. The precipitate was washed to neutral and dried to obtain rye pollen protein.

[0045] Combination Figure 1 It can be seen that ultrasonic combined with ultrahigh pressure treatment can improve the extraction rate of protein, and when the ratio of rye pollen to distilled water is 1:15, the maximum value is reached, and further increasing the amount of distilled water will not improve the extraction rate of protein. The cavitation effect of ultrasonic treatment causes the violent vibration of medium particles, leading to the mutual friction between medium particles, thereby destroying the surface of the pollen, and the ultrahigh pressure treatment is beneficial to the precipitation of protein.

[0046] Example 3: Effect of system pH on preparation of rye pollen peptide calcium chelate.

[0047] This example studies the effect of pH on the preparation of rye pollen peptide calcium chelate by adjusting the pH value of the system.

[0048] (1) Raw material pretreatment: The rye pollen was subjected to wall breaking and degreasing treatment, and the specific operation was as follows: the rye pollen was mixed with 75wt% ethanol at a ratio of 1:25, and placed in an ultrasonic reactor for double-frequency ultrasonic treatment, with an ultrasonic frequency of 20 / 40 kHz and a treatment time of 30 min.

[0049] (2) Protein extraction: the pretreated rye pollen was mixed with distilled water at a ratio of 1:15, and the pH of the system was adjusted to 10.5 using a sodium hydroxide solution under stirring. The system was subjected to ultrahigh pressure treatment for 10 min (300 MPa) and then treated at 60°C for 2 h. After filtration, the supernatant was separated, the pH of the system was adjusted to 4.3 using a hydrochloric acid solution, and the precipitate was obtained after filtration again. The precipitate was washed to neutral and dried to obtain rye pollen protein, which was used as needed.

[0050] (3) Preparation of rye pollen peptide calcium chelate:

[0051] The rye pollen and distilled water were mixed at a ratio of 1:10 and then put into a bubble reactor. The pH of the system was adjusted to 7, 8, 9, and 10 using a calcium hydroxide solution, and the mass of the added calcium hydroxide was recorded. The reaction temperature was set to 55°C. During the preparation, alkaline protease (0.5%, based on the rye pollen protein) was added, and when the pH of the system decreased to below 5.5, acid protease (1%, based on the rye pollen protein) was added. After the total reaction time reached 4 h, the system temperature was raised to 90°C for 15 min for enzyme inactivation. When the system temperature decreased to 50°C, carbon dioxide was introduced at a molar ratio of 1:1 with the calcium hydroxide. After standing for 30 min, the supernatant was filtered and spray-dried to obtain rye pollen peptide calcium powder.

[0052] The experimental results are shown in Figure 2 The abscissa represents the pH of the system solution, and the ordinate represents the yield of rye pollen peptide calcium powder. As can be seen from Figure 2 When the pH is 7-8, the chelation rate is low. When the initial pH is 9, the chelation rate is the highest, i.e., the yield of rye pollen peptide calcium powder is the highest, reaching 65.3%. This is because the alkaline protease has high activity at this pH, and the enzymatic ability is stronger than that at other pHs. When the pH continues to increase to 10, the chelation rate decreases. This is because the OH - group is too much, and calcium hydroxide precipitates with Ca 2+ , reducing the Ca 2+ available for chelation with polypeptides, which is not conducive to the chelation reaction.

[0053] Example 4: Effect of enzyme type on the preparation of rye pollen peptide calcium chelate.

[0054] In this example, the effect of enzyme type and addition amount on the preparation of rye pollen peptide calcium chelate was studied by adjusting the type and addition amount of protease. The optimal scheme in Example 3 was used for further study, and the details are as follows:

[0055] (1) Raw material pretreatment: The rye pollen was broken and defatted, and the specific operation was as follows: the rye pollen was mixed with 75wt% ethanol at a ratio of 1:25, placed in an ultrasonic reactor for double-frequency ultrasonic treatment, the ultrasonic frequency was 20 / 40 kHz, and the treatment time was 30 min.

[0056] (2) Protein extraction: the pretreated rye pollen was mixed with distilled water at a ratio of 1:15, the pH value of the system was adjusted to 10 using sodium hydroxide solution under stirring, and the system was treated under ultrahigh pressure for 10 min (300 MPa) and then treated at 60°C for 1.5 h; after filtration and separation of the supernatant, the pH value of the system was adjusted to 4.2 using hydrochloric acid solution, and the precipitate was obtained after filtration again, and then the precipitate was washed to neutral and dried to obtain rye pollen protein for standby.

[0057] (3) Preparation of rye pollen peptide calcium chelate: the rye pollen protein was mixed with water at a ratio of 1:10 and put into a bubble reactor, the pH value of the system was adjusted to 9 using calcium hydroxide solution, and the mass of added calcium hydroxide was recorded, and the reaction temperature was set to 55°C. One or more of alkaline protease / acidic protease / bromelain was added during the preparation (the addition time of acidic protease / bromelain was when the pH value of the system was reduced to below 5.5), and the specific addition amount was shown in Table 1.

[0058] After the total reaction time reached 4 h, the system temperature was raised to 90°C for 15 min for enzyme inactivation. After the system temperature dropped to 50°C, carbon dioxide was introduced, the molar mass ratio of introduced carbon dioxide to calcium hydroxide was 1:1, and after standing for 30 min, the supernatant was filtered and spray dried to collect rye pollen peptide calcium powder.

[0059] Table 1 Effect of enzyme and addition amount on preparation of rye pollen peptide calcium chelate

[0060]

[0061]

[0062] The experimental results are shown in Table 1, and the addition amount of alkaline protease or acidic protease affects the yield of rye pollen peptide calcium chelate. As shown in combination 1 to combination 4, when only alkaline protease is added, the addition amount of alkaline protease is 1.5%, and the yield of rye pollen peptide calcium chelate is the highest. As shown in combination 5 to combination 6, when only acidic protease is added, the addition amount of acidic protease is 2%, and the yield of rye pollen peptide calcium chelate is the highest.

[0063] In addition, since the rye pollen protein component is complex, combined treatment of multiple enzymes is beneficial to improve the yield of rye pollen peptide calcium powder. As can be seen from combinations 8 to 13, the addition of bromelain is beneficial to improve the yield of peptides, and therefore three-protease combinations are preferred as enzymatic agents.

[0064] Example 5: Effect of CO2 input amount on preparation of rye pollen peptide calcium chelate.

[0065] Steps (1) and (2) of this example are the same as those of Example 4.

[0066] Step (3) preparation of rye pollen peptide calcium chelate: rye pollen protein was mixed with water at a ratio of 1:10 and was fed into a bubble reactor. Calcium hydroxide solution was used to adjust the pH of the system to 9, and the mass of the added calcium hydroxide was recorded. The reaction temperature was set to 55°C. During the preparation, alkaline protease (1%, based on rye pollen protein) was added, and when the pH of the system decreased to 5.5, acid protease (1%, based on rye pollen protein) and bromelain (0.5%, based on rye pollen protein) were added. After the total reaction time reached 4h, the system temperature was raised to 90°C for 15min for enzyme inactivation. After the system temperature decreased to 50°C, carbon dioxide was introduced, and the molar mass ratio of carbon dioxide to calcium hydroxide was 0.5:1, 0.75:1, 1:1 or 1:0.75. After standing for 30min, the system was filtered, and the supernatant was spray-dried to obtain rye pollen peptide calcium powder.

[0067] The reaction of CO2 and Ca(OH)2 is a special reaction, and the product is different when the amount of reactant is different. When CO2 is in small amounts, calcium carbonate precipitate is formed, and when CO2 is in excess, soluble calcium bicarbonate is formed. The precipitation reaction of the two is an important process for separating protein peptides, and different calcium content peptides can be prepared by adjusting the molar mass ratio of CO2 to Ca(OH)2.

[0068] Figure 3 In the figure, the abscissa represents the ratio of CO2 to Ca(OH)2, and the ordinate represents the yield of rye pollen peptide calcium powder. As can be seen from the figure, Figure 3 When CO2 is in excess or in small amounts, the yield of peptides is higher, because the calcium content of the prepared rye pollen peptide calcium chelate is higher, and there are some calcium ions that have not been chelated. When the ratio of CO2 to Ca(OH)2 is 1:1, the two undergo a precipitation reaction, and most of the calcium has precipitated, so the measured Ca content in the product is reduced.

[0069] The infrared spectrum of rye pollen, rye pollen protein and rye pollen peptide was analyzed, and the results are shown in Figure 4 As can be seen from the figure, Figure 4It can be seen that the overall structure of the infrared spectra of the pollen and the proteins and peptides is not significantly different, only the intensity of some characteristic peaks changes. For example, the characteristic absorption peak of the hydroxyl group at 3400 cm -1 The characteristic absorption peak of the hydroxyl group is reduced, and the 1700 cm -1 ~ 1600 cm -1 The characteristic peak of the protein amide I band (C=O stretch, C-N stretch) at 1600 cm -1 ~ 1500 cm -1 The characteristic peak of the amide II band (N-H bend, C-N stretch, and C-C stretch) is reduced.

[0070] Example 6: Application of rye pollen peptide calcium chelate in frozen dough (disulfide bond, gluten index)

[0071] It is known that using the gel properties of a single or multiple food colloids to improve the freeze resistance of frozen dough is an effective way. Among them, sodium alginate is a commonly used protective agent, which is an ionic gelatinous hydrophilic polysaccharide that can combine with calcium ions to form a gel. The following discusses whether sodium alginate and calcium-containing peptide chelate have a synergistic effect on improving the freeze resistance of frozen dough.

[0072] In this example, the rye pollen peptide calcium powder with high Ca content obtained in Example 5 was used.

[0073] Step (4) Application of rye pollen peptide calcium chelate: The rye pollen peptide calcium powder was compounded with high-gluten wheat flour at a ratio of 0.1% to 1% to 100%, sodium alginate (0% to 1% of the weight of the flour) was added, and the mixture was mixed evenly. Then, 55% of the weight of the flour was added to the mixture and mixed with water to prepare a dough. The dough was placed in a -80°C refrigerator until the center temperature of the dough was -18°C, and then stored in a -18°C refrigerator to obtain a frozen dough. The experimental results are as follows:

[0074] The water in the dough forms solid ice through crystallization during freezing, and the ice crystal content and size are important indicators affecting the quality of frozen food. Disulfide bond is a key indicator for evaluating frozen dough. The addition of rye pollen peptide calcium chelate and sodium alginate improves the freeze resistance of the dough, thereby affecting the disulfide bond content. Disulfide bond is a key indicator for evaluating frozen dough. The addition of rye pollen peptide calcium chelate and sodium alginate improves the freeze resistance of the dough, thereby affecting the disulfide bond content.

[0075] Table 2 Effect of rye pollen peptide calcium chelate on frozen dough

[0076]

[0077] As can be seen from Table 2, dough samples A and D, the single rye pollen peptide calcium chelate can increase the gluten index and stable disulfide bond content of the dough.

[0078] As can be seen from Table 2, dough samples C, D, E and F, compared with the single rye pollen peptide calcium chelate, its combination with sodium alginate in proportion is more conducive to increasing the gluten index of the dough, which may be because sodium alginate is an ionic colloid, which can interact with Ca 2+ Cross-linking occurs, and both of them synergistically promote the interaction of colloid and gluten protein, and enhance the strength of gluten protein. When the content of rye pollen peptide calcium chelate is 0.5% and the content of sodium alginate is 1%, the increase in the gluten index of the dough is very significant, and the increase is not significant when the content of rye pollen peptide calcium chelate continues to increase.

[0079] In combination with Table 2 and Figure 5 As can be seen from the microstructure of the dough, the rye pollen peptide calcium chelate and sodium alginate can promote the aggregation of starch in the dough, while the single peptide or sodium alginate has no significant effect on the aggregation of starch.

[0080] Example 7: Effect of reactor on preparation of rye pollen peptide calcium chelate.

[0081] Figure 6 The effect of the reactor on the yield of rye pollen peptide calcium chelate is shown, from Figure 6 It can be seen that the bubbling reactor has higher peptide yield and smaller molecular weight peptides than the traditional stirring reactor.

[0082] Compared with the traditional stirring reactor, the bubbling reactor can improve the reaction efficiency. The system of the bubbling reactor is a system in which the traditional mechanical stirring is replaced by bubbling (inert gas N2), and the gas is introduced into the column reactor from the bottom, which can promote more sufficient mixing of the substrate and the enzyme, thereby improving the enzymolysis rate.

[0083] The traditional rapid mechanical stirring has greater destructive effect on the structure of the enzyme, thereby increasing the number of reuse of the enzyme. Therefore, the bubbling reactor has higher peptide yield and smaller molecular weight peptides than the traditional stirring reactor.

[0084] The test methods involved in the present application are:

[0085] Determination of protein extraction rate: the content of protein is detected according to the Kjeldahl method described in GB 5009.5-2016, and the mass ratio of the added pollen is the protein extraction rate.

[0086] Pollen peptide calcium powder yield: the specific gravity of the dried peptide and protein is the pollen peptide calcium powder yield.

[0087] Determination of molecular weight: The molecular weight of the peptide was determined by high performance size exclusion chromatography described in Appendix A of GB 31645-2018.

[0088] Determination of Ca content: The calcium content of the peptide was determined by atomic absorption spectrometer (AA 240, Varian, USA).

[0089] Determination of microstructure: The dough was crushed into powder, dried, coated on double-sided tape, and gold sprayed, and the surface microstructure was observed using a scanning electron microscope (Phenom Pro, Netherlands).

[0090] Determination of gluten index: The gluten index was determined according to GB / T 5506.2-2008 "Wheat and wheat flour gluten content Part 2: Determination of wet gluten by instrumental method".

[0091] Disulfide bond content: The disulfide bond content of the dough was determined according to the method of GAO Xueli. Mechanism of soybean 7S, 11S globulin and isolated protein affecting dough properties and quality of steamed buns [D]. Northwest A&F University, 2016.

[0092] The above only describes the preferred embodiments of the present application, and is not a limitation on the design of the present application. Any equivalent changes made according to the key design of the present application fall within the scope of protection of the present application.

Claims

1. The application of a rye pollen peptide calcium chelate in frozen dough, characterized in that: Rye pollen peptide calcium chelate was compounded with high-gluten wheat flour at a ratio of 0.1% to 1%: 100%, and 0%-1% sodium alginate by weight of the flour was added. The mixture was thoroughly mixed, and then 55% water by weight of the flour was added and mixed to form a dough. The dough was then placed in a -80°C freezer until the center temperature reached -18°C, and subsequently stored at -18°C to obtain frozen dough. The preparation method of the rye pollen peptide calcium chelate includes the following steps: (1) Raw material pretreatment: Rye pollen is subjected to cell wall breaking and defatting treatment; (2) Protein extraction: Protein was extracted by alkaline extraction and acid precipitation. Pretreated rye pollen was mixed with distilled water at a ratio of 1:10 to 1:

20. The pH of the system was adjusted to 10 to 11. After high pressure treatment for 10 min, the mixture was treated at 55 to 60 °C for 1.5 to 2 h. After filtration, the supernatant was obtained. The pH of the system was adjusted to 4.0 to 4.

5. After filtration again, the precipitate was obtained. The precipitate was washed to neutral and dried to obtain rye pollen protein for later use. (3) Preparation of rye pollen peptide calcium chelate: First, rye pollen protein is enzymatically hydrolyzed by mixing rye pollen and distilled water in a ratio of 1:15 to 1:25, adjusting the pH of the system to 7 to 9 with calcium hydroxide solution, and maintaining the reaction temperature at 45 to 55℃; protease is added during the reaction. After reacting for 2–4 hours, the enzyme was inactivated at 90°C for 10–15 minutes. Then, after the system temperature dropped to 50°C, carbon dioxide was introduced. By controlling the ratio of calcium hydroxide to carbon dioxide, rye pollen peptide calcium chelate was prepared.

2. The application of the rye pollen peptide calcium chelate as described in claim 1 in frozen dough, characterized in that: Step (1) Raw material pretreatment: Mix rye pollen with 75wt% ethanol at a ratio of 1:25, place it in an ultrasonic reactor for dual-frequency ultrasound, with an ultrasound frequency of 20 / 40 kHz and a treatment time of 30 min.

3. The application of the rye pollen peptide calcium chelate as described in claim 1 in frozen dough, characterized in that: In step (2), sodium hydroxide solution is first used to adjust the pH of the system to 10-11, and then hydrochloric acid solution is used to adjust the pH of the system to 4.0-4.

5.

4. The application of the rye pollen peptide calcium chelate as described in claim 1 in frozen dough, characterized in that: In step (3), after mixing rye pollen with distilled water, the mixture is added to a bubble reactor for reaction.

5. The application of the rye pollen peptide calcium chelate as described in claim 1 in frozen dough, characterized in that: In step (3), the protease is one or more of alkaline protease, acidic protease, or bromelain.

6. The application of the rye pollen peptide calcium chelate as described in claim 5 in frozen dough, characterized in that: In step (3), the mass percentages of each protease are as follows: alkaline protease accounts for 0.5% to 3% of the protein in rye pollen; acidic protease accounts for 1% to 2% of the protein in rye pollen; and bromelain accounts for 0.25% to 0.5% of the protein in rye pollen.

7. The application of the rye pollen peptide calcium chelate as described in claim 1 in frozen dough, characterized in that: In step (3), the molar mass ratio of carbon dioxide to calcium hydroxide is 0.5:1 to 1:0.

75.

8. The application of the rye pollen peptide calcium chelate as described in claim 1 in frozen dough, characterized in that: In step (3), carbon dioxide is introduced into the system in proportion, then allowed to stand, filtered, and the supernatant is dried to collect rye pollen peptide calcium chelate, which is rye pollen peptide calcium powder.

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