Improved crispy agent for fried dough twists and preparation process of improved crispy agent

Abstract

The invention provides an improved crisping agent for fried dough twists and a preparation process of the improved crisping agent, and belongs to the technical field of crisping agents. The preparation process comprises the following steps: preparing the compound leavening agent; preparing a compound fermentation liquid; extracting modified soluble dietary fibers; and preparing the improved crisp agent. The improved crispness agent is added in the preparation of the fried dough twist, so that the fried dough twist can form a structure which is dense inside and crispy outside, finally, the volume of the fried dough twist is increased, the texture is fluffy, the crispness of the fried dough twist is improved, and the retention time of the crispness is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of crispness agents, and particularly relates to an improved crispness agent for twist doughnuts and a preparation process thereof. Background Art

[0002] As a traditional deep-fried pasta, twist doughnuts are widely loved by consumers for their unique crispy, crunchy and fragrant taste. Its core quality characteristics lie in the porous, loose and crispy internal structure and the hard and crispy outer shell formed after deep-frying.

[0003] "Crispness" is the core index for evaluating the quality of twist doughnuts, directly affecting consumers' acceptance and the product's market competitiveness. An ideal twist doughnut should be melt-in-the-mouth, with a loose interior, no hard core, not gritty, no obvious sticky feeling after chewing, and can maintain a long-term taste stability.

[0004] Traditional twist doughnut making mainly achieves crispness through high-gluten flour, a large amount of oils (such as shortening, lard, etc.) and specific dough mixing, proofing, and deep-frying processes (such as high temperature, double frying). Although this method is effective, it has obvious deficiencies: repeated deep-frying results in high-calorie products, which does not conform to the modern healthy and low-fat consumption trend; the requirements for controlling deep-frying temperature and time are extremely strict, and a slight deviation is likely to cause the product to be too hard, too soft, or unable to achieve good crispness. It is difficult to ensure the stability between product batches; and the product is prone to moisture absorption and softening during storage and sales, losing its crispy characteristics and having a short shelf life.

[0005] Therefore, we propose an improved crispness agent for twist doughnuts and a preparation process thereof. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide an improved crispness agent for twist doughnuts and a preparation process thereof.

[0007] A preparation process of an improved crispness agent for twist doughnuts includes the following steps: S1: Preparation of compound leavening agent First, sodium bicarbonate is encapsulated to prepare sodium bicarbonate microcapsules, and then 0.4 - 0.5 parts by weight of citric acid, 0.3 - 0.4 parts by weight of calcium dihydrogen phosphate, 1 - 2 parts by weight of glucono-δ-lactone and sodium bicarbonate microcapsules are compounded to obtain a compound leavening agent; S2: Preparation of compound fermentation broth Trichoderma viride and Aspergillus niger are used to ferment navel orange peel powder to obtain a compound fermentation broth; S3: Extraction of modified soluble dietary fiber The compound fermentation broth is enzymatically hydrolyzed with α-amylase, glucosidase and papain respectively, and then centrifuged, ethanol-precipitated and dried to obtain modified soluble dietary fiber; S4: Preparation of Modified Crispy Agent Mix 20 - 30 parts by weight of soluble soybean polysaccharide, 10 - 20 parts by weight of potato starch, 5 - 8 parts by weight of sodium stearoyl lactate, 10 - 12 parts by weight of propylene glycol alginate, 20 - 30 parts by weight of coconut oil, 18 - 23 parts by weight of compound leavening agent, and 8 - 10 parts by weight of modified soluble dietary fiber for 20 - 30 min to obtain the modified crispy agent.

[0008] Furthermore, the preparation of the compound leavening agent in step S1 specifically includes the following steps: S1.1: Add glycerol monostearate to absolute ethanol, and then stir and mix at 45 - 50 °C and 180 - 200 rpm for 20 - 30 min to obtain a glycerol monostearate absolute ethanol solution with a concentration of 0.25 - 0.3 g / mL; S1.2: At 45 - 50 °C, add 2.4 - 3.2 parts by weight of sodium bicarbonate and 3 - 5 parts by weight of konjac gum to 20 - 23 parts by weight of the glycerol monostearate absolute ethanol solution, stir and mix at 200 - 300 rpm for 20 - 30 min, then add 20 - 30 parts by weight of saturated sodium bicarbonate solution, mix and place in an ice - water bath to cool down, and stir for 20 - 30 min. Finally, filter, dry, and pulverize to obtain sodium bicarbonate microcapsules; S1.3: Stir and mix 0.4 - 0.5 parts by weight of citric acid, 0.3 - 0.4 parts by weight of calcium dihydrogen phosphate, and 1 - 2 parts by weight of glucono - δ - lactone at 300 - 500 rpm for 10 - 12 min, then add 0.8 - 1.2 parts by weight of sodium bicarbonate microcapsules and mix for 20 - 30 min to obtain the compound leavening agent.

[0009] Furthermore, the preparation of the compound fermentation broth in step S2 specifically includes the following steps: S2.1: Take a freeze - dried tube of Trichoderma viride, wipe the surface of the freeze - dried tube with an alcohol cotton ball for disinfection, heat the top of the tube at the outer flame of an alcohol lamp, drip 2 - 3 drops of sterile water to break the tube wall, knock off the broken top, suck 0.5 - 1 mL of PDB medium into the freeze - dried tube to dissolve all the freeze - dried bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, and place it in a static constant - temperature culture at 28 °C for 7 d, and transfer it for three generations to obtain the cultured Trichoderma viride; S2.2: Take a freeze - dried tube of Aspergillus niger, wipe the surface of the freeze - dried tube with an alcohol cotton ball for disinfection, heat the top of the tube at the outer flame of an alcohol lamp, drip 2 - 3 drops of sterile water to break the tube wall, knock off the broken top, suck 0.5 - 1 mL of PDB medium into the freeze - dried tube to dissolve all the freeze - dried bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, and place it in a static constant - temperature culture at 28 °C for 7 d, and transfer it for three generations to obtain the cultured Aspergillus niger; S2.3: Add the cultured Trichoderma viride and Aspergillus niger after culturing into 5 - 10 mL of sterile water respectively. Then scrape the surface spores and put them into an Erlenmeyer flask, shake for 20 - 30 min, and then filter to obtain a Trichoderma viride spore suspension and an Aspergillus niger spore suspension; S2.4: Inoculate the Trichoderma viride spore suspension and the Aspergillus niger spore suspension into the fermentation medium at a total inoculation amount of 1.2 - 1.5% (v / v), and culture at 120 - 140 r / min and 28 °C for 2 - 3 d to obtain a composite fermentation broth.

[0010] Furthermore, the extraction of the modified soluble dietary fiber in step S3 specifically includes the following steps: S3.1: Sterilize the composite fermentation broth for 20 - 30 min, then adjust the pH to 6 - 6.3, add 1 - 2 parts by weight of α - amylase, shake in a water bath at 90 - 95 °C for 1 - 2 h, then cool to 60 - 62 °C, adjust the pH to 4.5 - 4.8, then add 0.1 - 0.3 parts by weight of glucosidase, then shake in a water bath at 60 - 65 °C for 30 - 40 min, finally add 0.1 - 0.3 parts by weight of papain, continue to shake for 30 - 40 min, and then inactivate the enzyme and centrifuge to obtain the centrifuged supernatant; S3.2: After vacuum - concentrating the centrifuged supernatant, add a 90 - 95 wt% ethanol solution to precipitate for 12 - 14 h, then filter, freeze - dry the precipitate, and then ball - mill for 1 - 2 h to obtain the modified soluble dietary fiber.

[0011] Furthermore, in step S2.3, the Trichoderma viride spore suspension and the Aspergillus niger spore suspension are inoculated in a ratio of 1 - 3:1 by volume.

[0012] Furthermore, in step S2.3, the concentrations of both the Trichoderma viride spore suspension and the Aspergillus niger spore suspension are 10 7 CFU / mL.

[0013] Furthermore, in step S2.3, the fermentation medium is prepared by mixing 5 g of navel orange peel powder, 2 g of glucose, 0.4 g of yeast extract powder, 0.2 g of K2HPO4, 100 mL of distilled water, adjusting the pH to 5.0, and sterilizing at 121 °C under high - pressure steam for 20 min.

[0014] Furthermore, the α - amylase in step S3.1 is a thermotolerant α - amylase.

[0015] An improved crispness agent for twist doughnuts, which is prepared by the preparation process of an improved crispness agent for twist doughnuts described in any one of the above.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The present invention uses konjac gum and glycerol monostearate to encapsulate sodium bicarbonate microcapsules. During the preparation of the sodium bicarbonate microcapsules, a saturated sodium bicarbonate solution is added. The saturated sodium bicarbonate solution is an alkaline solution, which will cause the deacetylation and gelation of konjac gum. And the saturated solution has a high concentration of sodium bicarbonate ions, and its sodium bicarbonate concentration can reach the maximum value. It can not only provide sufficient alkalinity to promote the structural transformation of konjac gum, but also strengthen the cross-linking degree of the gel network through the high ion concentration, playing a role in strengthening the main wall material konjac gum, improving the encapsulation rate of the sodium bicarbonate microcapsules, thereby improving the stability of the sodium bicarbonate microcapsules and avoiding gas loss caused by a large amount of gas production in the early stage.

[0017] 2. The sodium bicarbonate microcapsules of the present invention remain stable during the water addition and dough kneading and proofing stages of the twist due to the low-temperature environment, reducing gas loss caused by a large amount of gas production in the early stage. During the water addition and dough kneading and proofing stages, the slow-release efficiency of the sodium bicarbonate microcapsules is low, and only a small amount of sodium bicarbonate is slowly released. Citric acid and calcium dihydrogen phosphate release H + , upon contact with water, immediately react with the small amount of slowly released sodium bicarbonate to produce a small amount of initial gas, which helps the dough to initially form micro pores and provides a certain support for the gluten network. After high-temperature frying, the microcapsules rupture and release a large amount of sodium bicarbonate. The sodium bicarbonate reacts violently with the remaining acid agents of citric acid and calcium dihydrogen phosphate and the lactic acid produced by the hydrolysis of glucono-δ-lactone to form "explosive gas production". Since citric acid releases acid rapidly in the early stage, most of it is consumed during the proofing stage. Calcium dihydrogen phosphate releases acid slowly, and its dissociation under high-temperature frying will accelerate the release of H + , while glucono-δ-lactone is a delayed acid-releasing agent, which gradually hydrolyzes to produce lactic acid upon contact with water, and the acid-releasing rate is even slower, which can supplement the H + in the later stage of high-temperature frying, so as to achieve the effect of continuous gas production. At this time, the dough quickly solidifies in the oil temperature to form a fine and uniform pore structure. The staged gas production avoids gas loss caused by a large amount of gas production in the early stage. The concentrated gas production during frying causes the dough to quickly expand, forming a "crispy on the outside and tender on the inside" structure, finally increasing the volume of the twist and making its texture fluffy, and improving the crispness after frying.

[0018] 3. In the present invention, soluble soybean polysaccharide and propylene glycol alginate are used as hydrocolloids, which can form a viscous gel network in the system to encapsulate the gas generated by the compound leavening agent, prevent the bubbles from merging or escaping, make the pores fine and uniform, and improve the durability of the product's puffiness and crispness. The modified soluble dietary fiber has a porous structure and high water-holding capacity, and can form an interpenetrating network with soluble soybean polysaccharide and propylene glycol alginate to enhance the gas-holding capacity of the system and assist the compound leavening agent to maintain the bubble structure. At the same time, the modified soluble dietary fiber can interact with the starch chain through hydrogen bonds, physically hinder the rearrangement of starch molecules, and delay the retrogradation process, thereby prolonging the retention time of the crispy feeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings incorporated herein and constituting a part of the specification illustrate embodiments of the present invention and, together with the specification, are further used to explain the principles of the present invention and enable those skilled in the relevant art to implement and use the present invention.

[0020] Figure 1 It is a process flow chart of the preparation of an improved crisping agent for twist doughnuts adopted in the embodiments of the present invention. Detailed implementation manners

[0021] The following describes in detail an improved crisping agent for twist doughnuts and its preparation process provided by the present invention in conjunction with the accompanying drawings and specific embodiments. At the same time, it should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments. For some well-known technologies, those skilled in the art can also adopt other alternative methods for implementation; moreover, the accompanying drawings are only for more specifically describing the embodiments and are not intended to specifically limit the present invention. Embodiment 1

[0022] A preparation process of an improved crisping agent for twist doughnuts, as Figure 1 shown, includes the following steps: S1: Preparation of compound leavening agent S1.1: Add glycerol monostearate to absolute ethanol, and then stir and mix at 45°C and 180 rpm for 20 min to obtain a glycerol monostearate absolute ethanol solution with a concentration of 0.25 g / mL; S1.2: At 45°C, add 2.4 parts by weight of sodium bicarbonate and 3 parts by weight of konjac gum to 20 parts by weight of the glycerol monostearate absolute ethanol solution, stir and mix at 200 rpm for 20 min, then add 20 parts by weight of saturated sodium bicarbonate solution, mix and place in an ice-water bath to cool down, and stir for 20 min. Finally, filter, dry, and pulverize to obtain sodium bicarbonate microcapsules; S1.3: Stir and mix 0.4 parts by weight of citric acid, 0.3 parts by weight of calcium dihydrogen phosphate, and 1 part by weight of glucono-δ-lactone at 300 rpm for 10 min, then add 0.8 parts by weight of sodium bicarbonate microcapsules and mix for 20 min to obtain a compound leavening agent; S2: Preparation of compound fermentation broth S2.1: Take the Trichoderma viride freeze-dried tube and wipe the surface of the freeze-dried tube with alcohol cotton for disinfection. Heat the top of the tube at the outer flame of the alcohol lamp, drop 2 drops of sterile water to break the tube wall, knock off the broken top, suck 0.5 mL of PDB culture medium into the freeze-dried tube, dissolve all the freeze-dried bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, and place it in a static constant temperature culture at 28°C for 7 d, and transfer it for three generations to obtain the cultured Trichoderma viride; S2.2: Respectively take the lyophilized tubes of Aspergillus niger, wipe the surface of the lyophilized tubes with alcohol cotton for disinfection, heat the top of the tube in the outer flame of an alcohol lamp, drip 2 drops of sterile water to break the tube wall, knock off the broken top, aspirate 0.5 mL of PDB culture medium into the lyophilized tube, dissolve all the lyophilized bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, place it in a static constant temperature at 28 °C for 7 days, and transfer it for three generations to obtain the cultured Aspergillus niger; S2.3: Add the cultured Trichoderma viride and the cultured Aspergillus niger to 5 mL of sterile water respectively, then scrape the surface spores, put them into an Erlenmeyer flask, shake for 20 min, and then filter to obtain a Trichoderma viride spore suspension and an Aspergillus niger spore suspension; The concentrations of both the Trichoderma viride spore suspension and the Aspergillus niger spore suspension are 10 7 CFU / mL; S2.4: Inoculate the Trichoderma viride spore suspension and the Aspergillus niger spore suspension into the fermentation medium at a total inoculation amount of 1.2% (v / v), culture at 120 r / min and 28 °C for 2 days to obtain a composite fermentation broth; Prepare the fermentation medium by mixing 5 g of navel orange peel powder, 2 g of glucose, 0.4 g of yeast extract powder, 0.2 g of K2HPO4, 100 mL of distilled water, adjusting the pH to 5.0, and autoclaving at 121 °C for 20 min; The Trichoderma viride spore suspension and the Aspergillus niger spore suspension are inoculated in a volume ratio of 1:1; S3: Extraction of modified soluble dietary fiber S3.1: Sterilize the composite fermentation broth for 20 min, then adjust the pH to 6, add 1 part by weight of thermostable α-amylase, shake in a water bath at 90 °C for 1 h, then cool to 60 °C, adjust the pH to 4.5, then add 0.1 part by weight of glucoamylase, then shake in a water bath at 60 °C for 30 min, finally add 0.1 part by weight of papain, continue to shake for 30 min, then inactivate the enzyme and centrifuge to obtain the centrifuged supernatant; S3.2: After vacuum concentrating the centrifuged supernatant, add 90 wt% ethanol solution to precipitate for 12 h, then filter, freeze-dry the precipitate, and then ball-mill for 1 h to obtain the modified soluble dietary fiber; S4: Preparation of modified crispness enhancer Mix 20 parts by weight of soluble soybean polysaccharide, 10 parts by weight of potato starch, 5 parts by weight of sodium stearoyl lactate, 10 parts by weight of propylene glycol alginate, 20 parts by weight of coconut oil, 18 parts by weight of compound leavening agent and 8 parts by weight of modified soluble dietary fiber by stirring for 20 min to obtain the modified crispness enhancer. Example 2

[0023] A preparation process of a modified crispness enhancer for twist dough sticks, such asFigure 1 As shown in the figure, it includes the following steps: S1: Preparation of compound leavening agent S1.1: Add glycerol monostearate to absolute ethanol, and then stir and mix at 50°C and 200 rpm for 30 min to obtain a glycerol monostearate absolute ethanol solution with a concentration of 0.25 g / mL; S1.2: At 50°C, add 2.4 parts by weight of sodium bicarbonate and 3 parts by weight of konjac gum to 20 parts by weight of the glycerol monostearate absolute ethanol solution, stir and mix at 300 rpm for 30 min, then add 20 parts by weight of saturated sodium bicarbonate solution, cool the mixture in an ice-water bath, and stir for 30 min. Finally, filter, dry, and pulverize to obtain sodium bicarbonate microcapsules; S1.3: Stir and mix 0.4 parts by weight of citric acid, 0.3 parts by weight of calcium dihydrogen phosphate, and 1 part by weight of glucono-δ-lactone at 500 rpm for 12 min, then add 0.8 parts by weight of sodium bicarbonate microcapsules and mix for 30 min to obtain a compound leavening agent; S2: Preparation of compound fermentation broth S2.1: Take the freeze-dried tubes of Trichoderma viride respectively, wipe the surface of the freeze-dried tubes with alcohol cotton for disinfection, heat the top of the tube at the outer flame of an alcohol lamp, drop 2 drops of sterile water to break the tube wall, knock off the broken top, suck 0.5 mL of PDB medium into the freeze-dried tube, dissolve all the freeze-dried bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, and place it in a static constant temperature culture at 28°C for 7 d. Transfer it for three generations to obtain the cultured Trichoderma viride; S2.2: Take the freeze-dried tubes of Aspergillus niger respectively, wipe the surface of the freeze-dried tubes with alcohol cotton for disinfection, heat the top of the tube at the outer flame of an alcohol lamp, drop 2 drops of sterile water to break the tube wall, knock off the broken top, suck 0.5 mL of PDB medium into the freeze-dried tube, dissolve all the freeze-dried bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, and place it in a static constant temperature culture at 28°C for 7 d. Transfer it for three generations to obtain the cultured Aspergillus niger; S2.3: Add the cultured Trichoderma viride and the cultured Aspergillus niger to 5 mL of sterile water respectively, then scrape the surface spores, put them into a triangular flask, shake for 30 min, and then filter to obtain a Trichoderma viride spore suspension and an Aspergillus niger spore suspension; S2.4: Inoculate the Trichoderma viride spore suspension and the Aspergillus niger spore suspension into the fermentation medium at a total inoculation amount of 1.2% (v / v), and culture at 140 r / min and 28°C for 3 d to obtain a compound fermentation broth; Prepare the fermentation medium by adding 5 g of navel orange peel powder, 2 g of glucose, 0.4 g of yeast extract powder, 0.2 g of K2HPO4, 100 mL of distilled water, adjusting the pH to 5.0, and sterilizing at 121°C under high pressure steam for 20 min; The Trichoderma viride spore suspension and the Aspergillus niger spore suspension are inoculated in a volume ratio of 1:1; S3: Extraction of modified soluble dietary fiber S3.1: Sterilize the composite fermentation broth for 30 min, then adjust the pH to 6, add 1 part by weight of thermostable α-amylase, perform water bath oscillation at 95 °C for 2 h, then cool to 62 °C, and adjust the pH to 4.5, then add 0.1 part by weight of glucosidase, then perform water bath oscillation at 65 °C for 40 min, finally add 0.1 part by weight of papain, continue to oscillate for 40 min, then inactivate the enzyme and centrifuge to obtain the centrifuged supernatant; S3.2: After vacuum concentrating the centrifuged supernatant, add 90 wt% ethanol solution to precipitate for 14 h, then filter, freeze-dry the precipitate, and then ball mill for 2 h to obtain the modified soluble dietary fiber; S4: Preparation of modified crispness improver Mix 20 parts by weight of soluble soybean polysaccharide, 10 parts by weight of potato starch, 5 parts by weight of sodium stearoyl lactate, 10 parts by weight of propylene glycol alginate, 20 parts by weight of coconut oil, 18 parts by weight of compound leavening agent and 8 parts by weight of modified soluble dietary fiber by stirring for 30 min to obtain the modified crispness improver. Example 3

[0024] A preparation process of a modified crispness improver for twist doughnuts, as Figure 1 shown, includes the following steps: S1: Preparation of compound leavening agent S1.1: Add glycerol monostearate to absolute ethanol, then stir and mix at 45 °C and 180 rpm for 20 min to obtain a 0.3 g / mL glycerol monostearate absolute ethanol solution; S1.2: At 45 °C, add 3.2 parts by weight of sodium bicarbonate and 5 parts by weight of konjac gum to 23 parts by weight of glycerol monostearate absolute ethanol solution, stir and mix at 200 rpm for 20 min, then add 30 parts by weight of sodium bicarbonate saturated solution, cool the mixture in an ice-water bath and stir for 20 min, and finally filter, dry and pulverize to obtain sodium bicarbonate microcapsules; S1.3: Stir and mix 0.5 part by weight of citric acid, 0.4 part by weight of calcium dihydrogen phosphate and 2 parts by weight of glucono-δ-lactone at 300 rpm for 10 min, then add 1.2 parts by weight of sodium bicarbonate microcapsules and mix for 20 min to obtain the compound leavening agent; S2: Preparation of composite fermentation broth S2.1: Respectively take the freeze-dried tubes of Trichoderma viride, wipe the surface of the freeze-dried tubes with alcohol cotton for disinfection, heat the top of the tube at the outer flame of the alcohol lamp, drip 3 drops of sterile water to break the tube wall, knock off the broken top, aspirate 1 mL of PDB medium into the freeze-dried tube, dissolve all the freeze-dried bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, place it in a static constant temperature at 28 °C for 7 days, transfer it for three generations to obtain the cultured Trichoderma viride; S2.2: Respectively take the freeze-dried tubes of Aspergillus niger, wipe the surface of the freeze-dried tubes with alcohol cotton for disinfection, heat the top of the tube at the outer flame of the alcohol lamp, drip 3 drops of sterile water to break the tube wall, knock off the broken top, aspirate 1 mL of PDB medium into the freeze-dried tube, dissolve all the freeze-dried bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, place it in a static constant temperature at 28 °C for 7 days, transfer it for three generations to obtain the cultured Aspergillus niger; S2.3: Add the cultured Trichoderma viride and the cultured Aspergillus niger to 10 mL of sterile water respectively, then scrape the surface spores and put them into a triangular flask, shake for 20 min, and then filter to obtain a Trichoderma viride spore suspension and an Aspergillus niger spore suspension; S2.4: Inoculate the Trichoderma viride spore suspension and the Aspergillus niger spore suspension into the fermentation medium at a total inoculation amount of 1.5% (v / v), and culture at 120 r / min and 28 °C for 2 days to obtain a composite fermentation broth; Prepare the fermentation medium by mixing 5 g of navel orange peel powder, 2 g of glucose, 0.4 g of yeast extract powder, 0.2 g of K2HPO4, 100 mL of distilled water, adjusting the pH to 5.0, and autoclaving at 121 °C for 20 min; The Trichoderma viride spore suspension and the Aspergillus niger spore suspension are inoculated in a volume ratio of 3:1; S3: Extraction of modified soluble dietary fiber S3.1: Sterilize the composite fermentation broth for 20 min, then adjust the pH to 6.3, add 2 parts by weight of thermostable α-amylase, shake in a water bath at 90 °C for 1 h, then cool to 60 °C, adjust the pH to 4.8, then add 0.3 parts by weight of glucoamylase, then shake in a water bath at 60 °C for 30 min, finally add 0.3 parts by weight of papain, continue to shake for 30 min, then inactivate the enzyme and centrifuge to obtain the centrifuged supernatant; S3.2: After vacuum concentrating the centrifuged supernatant, add 95 wt% ethanol solution to precipitate for 12 h, then filter, freeze-dry the precipitate, and then ball-mill for 1 h to obtain the modified soluble dietary fiber; S4: Preparation of modified crispness improver Mix 30 parts by weight of soluble soybean polysaccharide, 20 parts by weight of potato starch, 8 parts by weight of sodium stearoyl lactate, 12 parts by weight of propylene glycol alginate, 30 parts by weight of coconut oil, 23 parts by weight of compound leavening agent and 10 parts by weight of modified soluble dietary fiber for 20 min to obtain the improved crispness agent.

[0025] Comparative Example 1 Compared with Example 1, the difference in Comparative Example 1 is that in Comparative Example 1, the compound leavening agent in Steps S1 and S4 is removed, and the remaining steps remain unchanged to prepare the improved crispness agent, denoted as Comparative Example 1.

[0026] Comparative Example 2 Compared with Example 1, the difference in Comparative Example 2 is that in Comparative Example 2, calcium dihydrogen phosphate and glucono-δ-lactone in Step S1.3 are replaced with citric acid, and the remaining steps remain unchanged to prepare the improved crispness agent, denoted as Comparative Example 2.

[0027] Comparative Example 3 Compared with Example 1, the difference in Comparative Example 3 is that in Comparative Example 3, glucono-δ-lactone in Step S1.3 is removed, and the remaining steps remain unchanged to prepare the improved crispness agent, denoted as Comparative Example 3.

[0028] Comparative Example 4 Compared with Example 1, the difference in Comparative Example 4 is that in Comparative Example 4, Step S2 is removed, and the compound fermentation broth in Step S3.1 is replaced with an equal mass of navel orange peel powder solution (obtained by adding 5 g of navel orange peel powder to 100 mL of distilled water), and the remaining steps remain unchanged to prepare the improved crispness agent, denoted as Comparative Example 4.

[0029] Comparative Example 5 Compared with Example 1, the difference in Comparative Example 5 is that in Comparative Example 5, the modified soluble dietary fiber in Steps S2 - S3 and S4 is removed, and the remaining steps remain unchanged to prepare the improved crispness agent, denoted as Comparative Example 5.

[0030] Comparative Example 6 Compared with Example 1, the difference in Comparative Example 6 is that in Comparative Example 6, the soluble soybean polysaccharide in Step S4 is removed, and the remaining steps remain unchanged to prepare the improved crispness agent, denoted as Comparative Example 6.

[0031] Comparative Example 7 Compared with Example 1, the difference in Comparative Example 7 is that in Comparative Example 7, the propylene glycol alginate in Step S4 is removed, and the remaining steps remain unchanged to prepare the improved crispness agent, denoted as Comparative Example 7.

[0032] Comparative Example 8 Compared with Example 1, the difference in Comparative Example 8 is that in Comparative Example 8, the sodium bicarbonate saturated solution in step S1.2 was removed, and the remaining steps remained unchanged to prepare the improved crispness agent, denoted as Comparative Example 8.

[0033] The improved crispness agents prepared in Examples 1-3 and Comparative Examples 1-7 were added to flour at a mass ratio of 1:100 to prepare twisted dough sticks.

[0034] The twisted dough sticks prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to a sensory evaluation of crispness. 20 professional sensory evaluators were randomly invited to establish individual evaluation rooms in accordance with the requirements of GB / T 13868-2009. The evaluators conducted sensory evaluations on the samples with numbers, and then took the arithmetic mean. The evaluation criteria refer to Table 1.

[0035]

[0036]

[0037] It can be seen from the data in Table 2 that the crispness of Comparative Examples 1-3 decreased significantly, indicating that adding a compound leavening agent can significantly improve the crispness after frying, and the compounding of citric acid, calcium dihydrogen phosphate and glucono-δ-lactone has a better crispness effect than using citric acid alone; it can be seen from the data in Comparative Examples 4-5 that the fermented and modified soluble dietary fiber can improve the crispness, making the twisted dough sticks obtain a lighter and more transparent crispness after frying.

[0038] The twisted dough sticks prepared in Examples 1-3 and Comparative Examples 4-7 were placed for 2 days and then the crispness was evaluated again. The evaluation results refer to Table 3.

[0039]

[0040] It can be seen from the data in Table 3 that the crispness of Examples 1-3 can be well maintained, and the crispness of Comparative Examples 4-5 decreased significantly, indicating that adding the modified soluble dietary fiber can extend the retention time of the crispness. It can be seen from the data in Comparative Examples 5-7 that adding soluble soybean polysaccharide, propylene glycol alginate and the modified soluble dietary fiber can improve the product crispness and the persistence of the crispness.

[0041] The encapsulation efficiency of the sodium bicarbonate microcapsules prepared in Examples 1-3 and Comparative Example 8 was measured. The measurement results refer to Table 4.

[0042]

[0043] It can be seen from the data in Table 4 that adding the sodium bicarbonate saturated solution can significantly improve the encapsulation efficiency of the sodium bicarbonate microcapsules.

[0044] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the relevant technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A preparation process of an improved crispness agent for twist doughnuts, characterized in that, It includes the following steps: S1: Preparation of compound leavening agent First, sodium bicarbonate is encapsulated to prepare sodium bicarbonate microcapsules, and then 0.4 - 0.5 parts by weight of citric acid, 0.3 - 0.4 parts by weight of calcium dihydrogen phosphate, 1 - 2 parts by weight of glucono-δ-lactone and sodium bicarbonate microcapsules are compounded to obtain the compound leavening agent; S2: Preparation of compound fermentation broth Trichoderma viride and Aspergillus niger are used to ferment navel orange peel powder to obtain the compound fermentation broth; S3: Extraction of modified soluble dietary fiber The compound fermentation broth is enzymatically hydrolyzed with thermostable α-amylase, glucosidase and papain respectively, and then centrifuged, ethanol-precipitated and dried to obtain the modified soluble dietary fiber; S4: Preparation of improved crispness agent 20 - 30 parts by weight of soluble soybean polysaccharide, 10 - 20 parts by weight of potato starch, 5 - 8 parts by weight of sodium stearoyl lactate, 10 - 12 parts by weight of propylene glycol alginate, 20 - 30 parts by weight of coconut oil, 18 - 23 parts by weight of compound leavening agent and 8 - 10 parts by weight of modified soluble dietary fiber are stirred and mixed for 20 - 30 min to obtain the improved crispness agent.

2. The preparation process of an improved crispness agent for twist doughnuts according to claim 1, characterized in that, For the preparation of the compound leavening agent in step S1, it specifically includes the following steps: S1.1: Glycerol monostearate is added to absolute ethanol, and then stirred and mixed at 45 - 50 °C and 180 - 200 rpm for 20 - 30 min to obtain a glycerol monostearate absolute ethanol solution with a concentration of 0.25 - 0.3 g / mL; S1.2: At 45 - 50 °C, 2.4 - 3.2 parts by weight of sodium bicarbonate and 3 - 5 parts by weight of konjac gum are added to 20 - 23 parts by weight of glycerol monostearate absolute ethanol solution, stirred and mixed at 200 - 300 rpm for 20 - 30 min, then 20 - 30 parts by weight of sodium bicarbonate saturated solution is added, and after mixing, it is placed in an ice-water bath to cool down and stirred for 20 - 30 min. Finally, it is filtered, dried and pulverized to obtain sodium bicarbonate microcapsules; S1.3: 0.4 - 0.5 parts by weight of citric acid, 0.3 - 0.4 parts by weight of calcium dihydrogen phosphate and 1 - 2 parts by weight of glucono-δ-lactone are stirred and mixed at 300 - 500 rpm for 10 - 12 min, and then 0.8 - 1.2 parts by weight of sodium bicarbonate microcapsules are added and mixed for 20 - 30 min to obtain the compound leavening agent.

3. The preparation process of an improved crispness agent for twist doughnuts according to claim 2, characterized in that, For the preparation of the compound fermentation broth in step S2, it specifically includes the following steps: S2.1: Take the freeze-dried tube of Trichoderma viride, wipe the surface of the freeze-dried tube with alcohol cotton for disinfection, heat the top of the tube at the outer flame of the alcohol lamp, drop 2 - 3 drops of sterile water to break the tube wall, knock off the broken top, suck 0.5 - 1 mL of PDB culture medium into the freeze-dried tube, dissolve all the freeze-dried bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, and place it in a static constant temperature culture at 28 °C for 7 d, and transfer it for three generations to obtain the cultured Trichoderma viride; S2.2: Wipe the surface of the Aspergillus niger freeze-dried tube with an alcohol cotton ball for disinfection. Heat the top of the tube in the outer flame of an alcohol lamp, drip 2 - 3 drops of sterile water to rupture the tube wall, knock off the ruptured top, aspirate 0.5 - 1 mL of PDB culture medium into the freeze-dried tube, dissolve all the freeze-dried bacterial powder to obtain a bacterial suspension, transfer the bacterial suspension to a PDA slant medium, and place it in a static constant temperature culture at 28°C for 7 days. Transfer it for three generations to obtain the cultured Aspergillus niger; S2.3: Add 5 - 10 mL of sterile water to the cultured Trichoderma viride and the cultured Aspergillus niger respectively. Then scrape the surface spores and put them into an Erlenmeyer flask, shake for 20 - 30 min, and then filter to obtain a Trichoderma viride spore suspension and an Aspergillus niger spore suspension; S2.4: Inoculate the Trichoderma viride spore suspension and the Aspergillus niger spore suspension into the fermentation medium at a total inoculation amount of 1.2 - 1.5% (v / v), and culture at 120 - 140 r / min and 28°C for 2 - 3 days to obtain a composite fermentation broth.

4. The preparation process of an improved crispness agent for twist doughnuts according to claim 3, characterized in that, Step S3: Extraction of modified soluble dietary fiber, specifically including the following steps: S3.1: Sterilize the composite fermentation broth for 20 - 30 min, then adjust the pH to 6 - 6.3, add 1 - 2 parts by weight of α - amylase, perform a water bath oscillation at 90 - 95°C for 1 - 2 h, then cool to 60 - 62°C, adjust the pH to 4.5 - 4.8, then add 0.1 - 0.3 parts by weight of glucosidase, then perform a water bath oscillation at 60 - 65°C for 30 - 40 min, finally add 0.1 - 0.3 parts by weight of papain, continue to oscillate for 30 - 40 min, then inactivate the enzyme and centrifuge to obtain a centrifuged supernatant; S3.2: After vacuum concentrating the centrifuged supernatant, add a 90 - 95 wt% ethanol solution to precipitate for 12 - 14 h, then filter, freeze-dry the precipitate, and then ball mill for 1 - 2 h to obtain modified soluble dietary fiber.

5. The preparation process of an improved crispness agent for twist doughnuts according to claim 3, characterized in that, In step S2.4, the Trichoderma viride spore suspension and the Aspergillus niger spore suspension are inoculated in a volume ratio of 1 - 3:

1.

6. The preparation process of an improved crispness agent for twist doughnuts according to claim 3, characterized in that, In step S2.4, the concentrations of both the Trichoderma viride spore suspension and the Aspergillus niger spore suspension are 10 7 CFU / mL.

7. The preparation process of an improved crispness agent for twist doughnuts according to claim 3, characterized in that, In step S2.4, the fermentation medium is prepared by mixing 5 g of navel orange peel powder, 2 g of glucose, 0.4 g of yeast extract powder, 0.2 g of K2HPO4, 100 mL of distilled water, adjusting the pH to 5.0, and sterilizing at 121°C under high pressure steam for 20 min.

8. The preparation process of an improved crispness agent for twist doughnuts according to claim 4, characterized in that, The α - amylase in step S3.1 is a thermotolerant α - amylase.

9. An improved crisping agent for twist doughnuts, characterized in that, It is prepared by the preparation process of an improved crispness agent for twist bread described in any one of claims 1 - 8.

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