Low glycemic index elaeagnus angustifolia naan and preparation method thereof

Abstract

The invention discloses a low-glycemic-index elaeagnus angustifolia naan and a preparation method thereof, and aims to solve the problems that a traditional elaeagnus angustifolia naan is high in glycemic index and is not suitable for people who control sugar and lose weight to eat. The method comprises the following steps: 1) preparing elaeagnus angustifolia dietary fiber powder, performing enzymolysis on elaeagnus angustifolia powder step by step through alpha-amylase, alkaline protease and saccharifying enzyme, and combining ultrasonic assistance and centrifugal separation to obtain high-purity dietary fibers; and (2) mixing the wheat flour, the elaeagnus angustifolia dietary fiber powder and the elaeagnus angustifolia fruit powder according to a mass part ratio of (85-90): (5-10): 5, performing dough kneading, performing fermentation twice, making crusty pancake blanks, and performing segmented temperature control baking. Experiments show that the starch hydrolysis rate of the prepared elaeagnus angustifolia naan is remarkably reduced, the glycemic index can be effectively reduced, the elaeagnus angustifolia naan is suitable for people who need to control blood sugar and lose weight, and meanwhile the flavor and nutrition of elaeagnus angustifolia are reserved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food processing, and particularly relates to a low-glycemic-index saussurea involucrata flatbread and a preparation method thereof. BACKGROUND

[0002] Saussurea involucrata is a characteristic food material in the northwest of China, rich in sugars, vitamins and minerals, and is often used to make traditional foods such as flatbread. Saussurea involucrata flatbread is loved by people because of its sweet taste and rich nutrition, but the high sugar content of saussurea involucrata fruit powder and the high starch content of wheat flour in traditional saussurea involucrata flatbread lead to a high glycemic index (GI), which can easily cause rapid blood sugar rise after eating, and is not suitable for people with diabetes, obese people and other groups who need to control blood sugar and calorie intake.

[0003] In the prior art, the method for reducing the glycemic index of cereal products is mostly to add dietary fiber (such as oat fiber, inulin, etc.), but excessive addition of exogenous dietary fiber may affect the flavor and texture of the flatbread. Therefore, how to reasonably determine the ingredient formula and preparation process of saussurea involucrata flatbread and effectively reduce the glycemic index of saussurea involucrata flatbread has become a technical problem to be solved. SUMMARY

[0004] The application prepares saussurea involucrata dietary fiber powder through a specific process, replaces part of the saussurea involucrata fruit powder and wheat flour, reduces the starch hydrolysis rate of saussurea involucrata flatbread, and thus reduces the glycemic index.

[0005] In one aspect, the application provides a preparation method of low-glycemic-index saussurea involucrata flatbread, which specifically comprises the following steps: S1: preparing saussurea involucrata dietary fiber powder: taking saussurea involucrata powder as raw material, adding water, and sequentially performing alpha-amylase hydrolysis, alkaline protease hydrolysis and saccharifying enzyme hydrolysis; finally, adjusting the system to neutral, taking the precipitate after centrifugal treatment, and drying to obtain saussurea involucrata dietary fiber powder; S2: mixing raw materials and kneading: first, mixing wheat flour, water, vegetable oil, active dry yeast and salt to knead, then adding water to wet the surface of the dough, and then adding saussurea involucrata fruit powder and saussurea involucrata dietary fiber powder prepared in step S1 to knead uniformly; S3: dough fermentation: fermenting the dough in a fermentation box at 30-35℃ for 0.8-1.2h; then kneading and dividing the fermented dough into small doughs, and fermenting the small doughs in a fermentation box at 30-35℃ for 8-15min; S4: making flatbread embryo; placing the flatbread embryo into an oven, preheating at 100℃ for 3-5min, and then baking at 200℃ with top and bottom heat for 12-17min to obtain the finished product.

[0006] Further, in step S1, the water is added in a liquid material ratio of 1:20 in saussurea involucrata powder.

[0007] Further, in step S1, the α-amylase hydrolysis refers to adding water to the jujube powder, adjusting the pH to 6-7, adding 1.5% α-amylase, ultrasonically treating at 37°C for more than 2 hours, and then inactivating the enzyme in a 100°C water bath for 5-10 minutes.

[0008] Further, in step S1, the alkaline protease hydrolysis refers to adding water to the jujube powder, adjusting the pH to 9-12, adding 1.2% alkaline protease, ultrasonically treating at 40-50℃ for more than 2 hours, and then inactivating the enzyme in a 100℃ water bath for 5-10 minutes.

[0009] Further, in step S1, the saccharifying enzyme hydrolysis refers to adding water to the jujube powder, adjusting the pH to 4-4.5, adding 1.5% saccharifying enzyme, ultrasonically treating at 60℃ for more than 2 hours, and then inactivating the enzyme in a 100℃ water bath for 5-10 minutes.

[0010] Further, in step S1, the centrifugation is carried out at a speed of 4800~5200 r / min for 10~15 min; the drying is freeze drying.

[0011] Further, in step S2, the amount of wheat flour added is 85-90 parts by weight; the amount of jujube dietary fiber powder added is 5-10 parts; and the amount of jujube fruit powder added is 5 parts.

[0012] Preferably, in step S2, the amount of the added jujube dietary fiber powder is 10 parts by weight, and the amount of the added jujube fruit powder is 5 parts.

[0013] Furthermore, the jujube fruit powder mentioned in step S2 refers to the jujube fruit powder obtained by washing and drying the jujubes, removing the pits, grinding them, and passing them through a 400-mesh sieve.

[0014] Further, in step S2, the amount of water added is 55 parts, the amount of vegetable oil added is 8 parts, the amount of active dry yeast added is 1 part, and the amount of salt added is 1 part by weight.

[0015] On the other hand, the present invention provides a low glycemic index jujube naan prepared according to the above method.

[0016] Compared with the prior art, the present invention has the following advantages: 1. The jujube dietary fiber powder prepared by this invention has high purity, excellent water-holding and oil-holding properties, and can effectively delay starch hydrolysis. Experimental data show that the starch hydrolysis rate of the product with added jujube dietary fiber is 45.97%~53.51%, significantly lower than that of ordinary naan (60.31%), and the glycemic index is significantly reduced.

[0017] 2. This invention uses 5-10 parts of jujube dietary fiber and 5 parts of jujube fruit powder added to wheat flour to prepare jujube naan. Compared with jujube naan prepared by directly adding dietary fiber, the starch hydrolysis rate and glycemic index are lower. Data shows that the starch hydrolysis rates of jujube naan prepared by adding only 5 parts and 10 parts of jujube dietary fiber are 52.07% and 51.61%, respectively. The starch hydrolysis rates of jujube naan prepared by adding 5 parts and 10 parts of jujube dietary fiber combined with 5 parts of jujube fruit powder are 50.92% and 45.97%, respectively, representing reductions of 2.2% and 10.9%.

[0018] 3. This invention retains 5 parts of the jujube fruit powder, maintaining the natural flavor and nutrition of the jujube, and solving the problem of flavor loss caused by simply adding exogenous dietary fiber. Specific Implementation Example 1: 1. Preparation of Jujube dietary fiber: Take 40g of jujube powder, add water at a liquid-to-solid ratio of 1:20, adjust the pH to 7, add 1.5% α-amylase, sonicate at 37℃ for more than 2 hours, then inactivate the enzyme in a 100℃ water bath for 5 minutes, adjust the pH to 9, add 1.2% alkaline protease, sonicate at 40-50℃ for more than 2 hours, inactivate the enzyme in a 100℃ water bath for 5 minutes, adjust the pH to 4.5, add 1.5% saccharifying enzyme, sonicate at 60℃ for more than 2 hours, then inactivate the enzyme at 100℃ for 5 minutes, adjust the pH to neutral, centrifuge (5000r, 10min), collect the precipitate and freeze-dry to obtain jujube dietary fiber powder.

[0020] 2. Ingredient preparation and dough preparation: Combine 85 parts wheat flour, 1 part active dry yeast, 1 part salt, 8 parts vegetable oil, and 55 parts water. Mix the ingredients according to the proportions to form a dough. After forming a dough, add a small amount of water to moisten the surface of the dough. Then, add 5 parts of jujube fruit powder and 10 parts of jujube dietary fiber to the dough and knead until evenly mixed. 3. First proofing: Ferment the prepared dough in a proofing box at 35 ℃ for 1 hour; 4. Second proofing: Knead the fermented dough and divide it into multiple small dough balls. Proof in a proofing box at 35 ℃ for 10 minutes. 5. Making the naan dough: Shape the proofed dough into round, flatbread-like naan dough that is thinner in the middle and thicker at the edges. Use a naan needle to poke holes in the center of the naan to create patterns. Sprinkle sesame seeds, raisins, or brush honey water on the surface. 6. Baking the naan: Place the prepared naan in the oven and preheat it to 100℃ for 3 minutes. Then increase the baking temperature to 200℃ with both top and bottom heat and bake for 15 minutes.

[0021] 7. Cool the finished product: Place the baked naan bread at room temperature to cool, and you will get the finished naan bread.

[0022] Example 2: Same as Example 1, except that in step 2, when preparing the ingredients for kneading the dough, the amount of wheat flour is 90 parts and the amount of jujube dietary fiber is 5 parts.

[0023] Comparative Example 1: Similar to Example 1, except that in step 2, when preparing the ingredients for kneading the dough, the amount of wheat flour is 85 parts, the amount of jujube dietary fiber is 15 parts, and there is no jujube fruit powder.

[0024] Comparative Example 2: Similar to Example 1, except that in step 2, when preparing the ingredients for kneading the dough, the amount of wheat flour is 90 parts, the amount of jujube dietary fiber is 10 parts, and there is no jujube fruit powder.

[0025] Comparative Example 3: Similar to Example 1, except that in step 2, when preparing the ingredients for kneading the dough, the amount of wheat flour is 95 parts, the amount of jujube dietary fiber is 5 parts, and there is no jujube fruit powder.

[0026] Comparative Example 4: Same as Example 1, except that in step 2, when preparing the ingredients for kneading the dough, 100 parts of wheat flour are used, without any jujube dietary fiber or jujube fruit powder.

[0027] Comparative Example 5: Same as Example 1, except that in step 2, when preparing the ingredients for kneading the dough, there are 95 parts wheat flour and 5 parts jujube fruit powder, without jujube dietary fiber.

[0028] Comparative Example 6: Similar to Example 1, except that in step 2, when preparing the ingredients for kneading the dough, there are 85 parts wheat flour and 15 parts jujube fruit powder, without jujube dietary fiber.

[0029] Comparative Example 7: Similar to Example 2, except that in step 2, 85 parts wheat flour, 1 part active dry yeast, 1 part salt, 8 parts vegetable oil, 55 parts water, 5 parts jujube fruit powder, and 10 parts jujube dietary fiber are mixed together and kneaded.

[0030] Test example: 1. Sensory evaluation The sensory evaluation of the test samples provided in Examples 1-2 and Comparative Examples 1-7 above, and the scoring criteria are shown in Table 1.

[0031] Table 1 Sensory Evaluation Criteria

[0032] The test results showed that Examples 1-2 exhibited the best performance in terms of texture, palatability, appearance, color, and flavor; Comparative Example 7 showed obvious defects in terms of texture, appearance, color, and flavor; Comparative Example 4 performed poorly in terms of palatability, appearance, color, and flavor; and Comparative Example 6 had poor palatability.

[0033] The scoring results are detailed in Table 2, where the groups “(1)(2)(3)” appearing in the table represent three parallel experiments.

[0034] Table 2: List of Sensory Rating Results

[0035] 2. Naan quality analysis The naan bread prepared in two embodiments and seven comparative examples of the present invention were used to measure the hardness, elasticity, chewiness, adhesiveness, cohesiveness and other indicators of the naan core and the naan edge.

[0036] Table 3. Texture results of naan bread filling

[0037] Using "soft and easy to chew, smooth texture, and no stickiness" as the core evaluation criteria, Example 1 showed the best texture among all samples. Specifically: 1. The lowest hardness index means that no force is needed to bite when eating, which lays the foundation for the core experience of "soft and easy to chew" from the basic texture. 2. The elasticity is at a moderate level and significantly higher than that of the comparative example 4, which not only ensures the softness of the texture, but also gives the sample a moderate rebound and toughness, avoiding problems such as becoming mushy or crumbling when eating, while maintaining the integrity of the naan core structure, further enhancing the "soft and textured" chewing experience. 3. The bite effectively reduces the oral burden during daily eating, perfectly meeting the core requirement of "soft and easy to chew"; 4. The sample has outstanding non-sticky properties, leaving the mouth feeling fresh and without any sticky residue after consumption, directly meeting the key evaluation criterion of "non-sticky" and significantly improving the enjoyment of eating; 5. The adhesiveness is within a moderate range, allowing the naan filling to form a slight fit in the mouth. Combined with its low hardness and high elasticity, this further optimizes the "smooth taste" experience. 6. Although the cohesiveness is not outstanding, it is sufficient to ensure that the naan filling does not easily break or fall apart during consumption, fully meeting the practical needs of daily consumption scenarios.

[0038] Compared to Example 1, Comparative Example 7 has higher hardness and lower elasticity, with significantly increased chewiness and adhesiveness, indicating that the sample texture is too hard and the internal network structure has not formed well, requiring effort to eat. This may be because the dietary fiber of the jujube has a high water-holding capacity, which "locks in" moisture, making it difficult for the protein and starch in the flour to fully absorb the moisture, resulting in insufficient gluten formation, poor dough extensibility, and a denser structure after baking.

[0039] Table 4. Texture results of naan bread edges

[0040] Using "easy to chew, not gritty, moderately chewy, and non-sticky" as the core evaluation criteria, Example 1 showed moderate hardness, indicating that the sample was soft to the touch and did not have the problem of being "too hard or gritty." It also showed moderate elasticity, with low levels of chewiness and adhesiveness, indicating that the sample could be easily chewed without repeated biting, was non-sticky, and left the mouth feeling refreshed after consumption, without any residual stickiness, thus not causing any burden on daily eating. Simultaneously, moderate adhesiveness and cohesion ensured stable taste and structure. Comparing Comparative Example 7 with Example 1, the results, similar to the texture of the naan bread core, indicate that the dietary fiber from sea buckthorn is not suitable for direct addition to wheat flour and mixing with other ingredients. Therefore, this invention proposes a unique process of first kneading the dough to form a ball and then adding the dietary fiber from sea buckthorn.

[0041] 3. Experimental Example: In vitro digestion performance determination Simulated in vitro digestion was used to determine the starch hydrolysis rate, and the results are shown in Table 5. As can be seen from Table 5, the starch hydrolysis rate of the jujube naan prepared using this method (Examples 1-2) was lower than that of naan with only jujube dietary fiber added (Comparative Examples 1-3), ordinary naan (Comparative Example 4), and naan made with only jujube fruit powder added (Comparative Examples 5-6). This is because the addition of jujube dietary fiber can form a physical barrier, slowing down the release of glucose and reducing the contact between α-amylase and starch, thus playing a dominant role in delaying starch hydrolysis. While polyphenols and other substances in jujube fruit powder inhibit α-amylase activity and can help slow down starch hydrolysis, excessive dietary fiber (Comparative Example 1) may affect the dough's network structure, reducing its ability to encapsulate and block starch. Amylase can then more easily contact exposed starch granules, quickly bind to and decompose starch, ultimately resulting in a rebound in the starch hydrolysis rate. Therefore, Example 1 has a lower starch hydrolysis rate compared to Comparative Examples 1 and 2, and Example 2 has a lower degree of starch hydrolysis compared to Comparative Examples 2 and 3. It can be concluded that the jujube naan prepared by this method is more suitable for people who need to control blood sugar and lose weight. The jujube naan prepared by adding 10% jujube dietary fiber and 5% jujube fruit powder has the best effect.

[0042] Table 5 Starch hydrolysis rate

[0043] The glycemic index (eGI) was predicted by calculating the starch hydrolysis rate using a first-order kinetic model C. t =C ∞ (1-e) -kt The hydrolysis process of the sample is fitted, and the hydrolysis index (HI) and the estimated glycemic index (eGI) of the sample are calculated based on the area under the curve.

[0044]

[0045] In the formula: C t C represents the percentage of starch hydrolyzed at time t. ∞ The value represents the equilibrium percentage of starch hydrolyzed at the end of the reaction; k represents the first-order digestion kinetic constant; and t represents time.

[0046] By fitting the data from the starch hydrolysis equation, C can be obtained. ∞ Given the k value, the area under the curve (AUC) is calculated using formula (2).

[0047]

[0048] In the formula: C ∞ The concentration at equilibrium; t ∞ t represents the final time (180 min); t0 represents the initial reaction time (0 min); k represents the kinetic constant.

[0049] Using white bread as a reference sample, the hydrolysis index (HI) of naan bread on the effect of the amount of dietary fiber added from jujube can be obtained, as shown in formula (3).

[0050]

[0051] The glycemic index is expected to be calculated using the following formula (4).

[0052]

[0053] Table 6 Expected Glycemic Index

[0054] As can be seen from Table 6, the naan prepared using the proportions described in the two embodiments of the present invention has a glycemic index prediction value of less than 50, which is a low-GI food. Therefore, it has an even lower eGI value and is a food that diabetic patients can eat with peace of mind.

Claims

1. A method for preparing low glycemic index jujube naan, characterized in that, Includes the following steps: S1: Preparation of sea buckthorn dietary fiber powder: using sea buckthorn powder as raw material, water is added, and the mixture is successively hydrolyzed by α-amylase, alkaline protease, and saccharifying enzyme; finally, the system is adjusted to neutral, the precipitate is collected by centrifugation, and dried to obtain sea buckthorn dietary fiber powder; S2: Ingredient preparation and dough preparation: First, mix wheat flour, water, vegetable oil, active dry yeast, and salt to form a dough. Then, add water to moisten the surface of the dough. Next, add the jujube fruit powder and the jujube dietary fiber powder prepared in step S1, and knead until evenly mixed. S3: Dough proofing: Ferment the dough in a proofing box at 30~35℃ for 0.8~1.2h; then knead the fermented dough and divide it into small dough balls, and proof them in a proofing box at 30~35℃ for 8~15min; S4: Make the naan dough; place it in the oven, preheat at 100℃ for 3~5 minutes, then bake at 200℃ for 12~17 minutes to obtain the finished product.

2. The method according to claim 1, characterized in that, In step S1, adding water refers to adding water at a liquid-to-material ratio of 1:

20.

3. The method according to claim 1, characterized in that, In step S1, the α-amylase hydrolysis refers to adding water to the jujube powder, adjusting the pH to 6-7, adding 1.5% α-amylase, ultrasonically treating at 37℃ for more than 2 hours, and then inactivating the enzyme in a 100℃ water bath for 5-10 minutes.

4. The method according to claim 1, characterized in that, In step S1, the alkaline protease hydrolysis refers to adding water to the jujube powder, adjusting the pH to 9-12, adding 1.2% alkaline protease, ultrasonically treating at 40-50℃ for more than 2 hours, and then inactivating the enzyme in a 100℃ water bath for 5-10 minutes.

5. The method according to claim 1, characterized in that, In step S1, the enzymatic hydrolysis of saccharifying enzyme refers to adding water to the jujube powder, adjusting the pH to 4-4.5, adding 1.5% saccharifying enzyme, ultrasonically treating at 60℃ for more than 2 hours, and then inactivating the enzyme in a 100℃ water bath for 5-10 minutes.

6. The method according to claim 1, characterized in that, In step S1, the centrifugation is carried out at a speed of 4800~5200 r / min for 10~15 min; the drying is freeze drying.

7. The method according to claim 1, characterized in that, In step S2, the amount of wheat flour added is 85-90 parts by weight; the amount of jujube dietary fiber powder added is 5-10 parts; and the amount of jujube fruit powder added is 5 parts.

8. The method according to claim 1, characterized in that, In step S2, the amount of the added jujube dietary fiber powder is 10 parts by weight, and the amount of the added jujube fruit powder is 5 parts.

9. The method according to claim 1, characterized in that, In step S2, by mass, the amount of water added is 55 parts, the amount of vegetable oil added is 8 parts, the amount of active dry yeast added is 1 part, and the amount of salt added is 1 part.

10. A low glycemic index jujube naan, characterized in that, Prepared by the method according to any one of claims 1-9.

Images