Qi-holding and aroma-enhancing rapid fermentation composite leavening agent for naan and preparation method of composite leavening agent

Abstract

The invention belongs to the technical field of food fermentation, and provides a naan air-holding aroma-enhancing rapid fermentation composite leavening agent and a preparation method, the composite leavening agent comprises freeze-drying type lactobacillus plantarum, freeze-drying type saccharomyces cerevisiae, freeze-drying type pediococcus pentosaceus, lactobacillus rhamnosus, lactobacillus casei and Xiangba powder, and the optimal mass ratio of the freeze-drying type lactobacillus plantarum, the freeze-drying type saccharomyces cerevisiae, the freeze-drying type pediococcus pentosaceus, the lactobacillus rhamnosus, the lactobacillus casei and Xiangba powder is 2: 1: 3: 2: 3: 1 or 3: 1: 3: 1: 2: 2. The crusty pancake prepared according to the proportion has better sensory characteristics, specifically, the crusty pancake tastes softer and more elastic, the surface glossiness is improved, and the color is more uniform and natural. In addition, the method can also shorten the fermentation time, and endows the product with unique aroma of the sour dough fermented crusty pancake, thereby enhancing the flavor of the final product. The problems that the taste and the flavor are single when commercial yeast is independently used for making the fermented crusty pancake are solved, and the problems that when traditional sour dough is used for making fermented flour products, the fermentation time is long, the stability is poor, the quality is difficult to control, harmful microorganisms are prone to breeding and the like are solved.

Description

Technical Field

[0001] This invention belongs to the field of food fermentation technology, and relates to compound fermentation agents, specifically to a gas-retaining and aroma-enhancing rapid fermentation compound fermentation agent for naan and its preparation method. Background Technology

[0002] Naan, a representative traditional bread product of Xinjiang Uyghur Autonomous Region, carries rich cultural connotations and is deeply loved by consumers. In its production process, dough fermentation is a crucial step determining product quality, directly affecting the naan's texture, flavor, and shape. Currently, naan production mainly relies on commercial yeast fermentation technology, which, while meeting basic needs, results in a relatively limited range of flavors and textures, restricting the expansion of consumption scenarios and the release of market potential. In contrast, sourdough fermentation, with its unique microbial diversity, endows naan with a distinctive flavor and texture, making it highly popular among consumers. However, traditional sourdough fermentation methods face challenges such as long production cycles, poor microbial stability, and environmental interference. This not only affects production efficiency but may also lead to the growth of unwanted bacteria, compromising product safety.

[0003] To address these issues, the industry has experimented with simple compound leavening agents; however, the results have fallen short of expectations, often failing to effectively balance the need for traditional flavors and rapid fermentation, and resulting in poor sensory quality in the products. Therefore, developing a novel compound leavening agent to replace traditional sourdough starter has become an urgent industry need.

[0004] To address the above problems, this invention provides a gas-retaining and aroma-enhancing rapid fermentation compound starter for naan bread and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a gas-retaining, aroma-enhancing, and rapid fermentation compound leavening agent for naan bread and its preparation method. This compound leavening agent improves the fermentation characteristics of the prepared naan, specifically resulting in a softer and more elastic texture, increased surface gloss, and a more uniform and natural color. Furthermore, this method shortens the fermentation time and imparts a unique aroma to the fermented naan, thereby enhancing the flavor of the final product. This invention solves the problems of monotonous taste and flavor associated with using commercial yeast alone to make fermented naan, as well as the problems of long fermentation times, nutrient degradation, and the potential for harmful microorganisms associated with using traditional sourdough to make fermented dough products.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] This invention provides a gas-retaining and aroma-enhancing rapid fermentation compound starter for naan bread. The components of the compound starter include freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosaceus, Lactobacillus rhamnosus, Lactobacillus casei, and spice powder.

[0008] This invention also provides a method for preparing a gas-retaining and aroma-enhancing rapid fermentation compound starter for naan bread, specifically including the following steps:

[0009] S1: Five representative sourdough samples from Xinjiang Uygur Autonomous Region were isolated and identified, and brewer's yeast, lactobacillus plantarum and Pediococcus pentosaceus were screened out;

[0010] S2: After freeze-drying brewer's yeast, lactobacillus plantarum and Pediococcus pentosus, they are combined with commercially available lactobacillus rhamnosus, lactobacillus casei and flavoring yeast to optimize the strain ratio. After optimization, they are mixed according to the mass ratio to prepare a compound fermentation agent.

[0011] Preferably, the mass ratio of the freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder is 1~3∶1~3∶1~3∶1~3∶1~3∶1~3∶1~3.

[0012] Preferably, the mass ratio of the freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosus, Lactobacillus rhamnosus, Lactobacillus casei to the Xiangba powder is 2:1:3:2:3:1 or 3:1:3:1:2:2.

[0013] The present invention also provides the application of the composite fermenting agent obtained by the above preparation method in the fermentation of naan.

[0014] Preferably, the specific steps for fermenting and making naan are as follows:

[0015] S1: Weigh the flour, add the corresponding amount of water according to the flour's water absorption rate, then add the compound leavening agent and salt, mix well and knead into a dough;

[0016] S2: Use a single fermentation process to ferment the kneaded dough for 1.5~2 hours;

[0017] S3: Divide the fermented dough into 150~200g portions, shape them into round naan dough, and deflate and stamp them.

[0018] S4: Bake the naan dough at a temperature of 220~230℃ for 15~18 minutes until the surface of the naan turns golden brown.

[0019] Preferably, the mass ratio of flour, compound leavening agent and salt is 1200~1500:36~45:7~9.

[0020] Preferably, the fermentation conditions are: humidity 50%~55% and temperature 30~35℃.

[0021] Preferably, the compound leavening agent is used to reduce the hardness of the naan, shorten the fermentation time, and enhance the flavor and texture of the naan.

[0022] Preferably, the flavor includes, but is not limited to, alcohols, esters, aldehydes, ketones, furans, pyrazines, and amines.

[0023] The beneficial effects of this invention are:

[0024] This invention provides a method for preparing a compound leavening agent, which aims to improve the gas retention of dough, accelerate the fermentation process, and enhance aroma, belonging to the field of food fermentation technology. This compound leavening agent is formulated through a synergistic ratio of functional strains and aroma-enhancing components. Specifically, it includes *Saccharomyces cerevisiae* (the core gas-producing strain), *Pediococcus pentosaceus*, *Lactobacillus plantarum*, *Lactobacillus rhamnosus*, and *Lactobacillus casei* (four functional lactic acid bacteria that work together to improve the texture and flavor of the dough), as well as an aroma-enhancing component (fragrant powder). The components are mixed in a specific ratio to solve the problems of monotonous taste and flavor associated with using commercial yeast alone to make fermented naan bread, and also address the issues of long fermentation times, nutrient degradation, and the potential for harmful microorganisms associated with using traditional sourdough to make fermented dough products.

[0025] The main purpose of this invention is to replace traditional sourdough and solve the problems of "long fermentation cycle, poor stability, and difficulty in quality control" that exist in the fermentation process of traditional sourdough. When making naan using this compound leavening agent, it can not only retain the rich traditional flavor unique to sourdough fermentation, but also significantly improve the sensory quality of naan—specifically, it is softer and more elastic in texture, has a higher surface gloss, and a more uniform and natural color. More importantly, it greatly shortens the naan production cycle, eliminating the need for a day of pre-fermentation of the sourdough (traditional sourdough fermentation takes 8-10 hours). The entire dough fermentation process only takes 1.5-2 hours to meet the processing requirements, significantly improving production efficiency while ensuring the traditional flavor and quality of naan products, and meeting the needs of industrial-scale production.

[0026] This invention provides a gas-retaining, aroma-enhancing, and rapid fermentation compound starter for naan bread and its preparation method. Naan prepared using this compound starter exhibits better fermentation characteristics, a softer and more elastic texture, and a more uniform and natural color. Furthermore, this method can shorten fermentation time and impart a unique aroma to the fermented naan, thereby enhancing the flavor of the final product. Attached Figure Description

[0027] Figure 1 This is a flowchart of the naan-making method in this invention;

[0028] Figure 2 This is the result of radar chart analysis of the sensory evaluation of naan in this invention;

[0029] Figure 3 This is the volatile fingerprint spectrum of naan in this invention;

[0030] Figure 4 This is a background subtraction image of the volatile content of naan in this invention;

[0031] Figure 5 This is a three-dimensional spectrum of the volatile components of naan bread in this invention;

[0032] Figure 6 This is the PCA analysis chromatogram of the volatile components of naan in this invention;

[0033] Figure 7 This is a PLSD analysis diagram of the volatile components of naan in this invention;

[0034] Figure 8 This is a VIP analysis chart of the volatile components of naan in this invention;

[0035] Figure 9 This is an analysis diagram of the volatile components of naan in this invention. Detailed Implementation

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0037] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0039] Example 1

[0040] Preparation of compound fermentation agent

[0041] S1: Five representative sourdough strains from Xinjiang Uygur Autonomous Region were isolated, yielding a total of 77 lactic acid bacteria and 49 yeast strains. The dominant strains were freeze-dried and identified, and the results showed that Saccharomyces cerevisiae, Lactobacillus plantarum, and Pediococcus pentosaceus were the dominant microorganisms in sourdough from Xinjiang Uygur Autonomous Region.

[0042] S2: To further enhance the vitality, stability, and fermentation flavor of the strains, the isolated brewing yeast, Lactobacillus plantarum, and Pediococcus pentosaceus were freeze-dried and then combined with commercially available Lactobacillus rhamnosaceus, Lactobacillus casei, and flavor-enhancing yeast to optimize the strain ratio. After optimization, they were mixed at a specific mass ratio to prepare a compound fermentation agent. The mass ratio of each component is: freeze-dried Lactobacillus plantarum : freeze-dried brewing yeast : freeze-dried Pediococcus pentosaceus : Lactobacillus rhamnosaceus : Lactobacillus casei : flavor powder = 2 : 1 : 3 : 2 : 3 : 1.

[0043] Preparation of naan

[0044] S4: Weigh 1200 g of flour according to the ratio, add the corresponding amount of water according to the water absorption rate of the flour, then add 36 g of compound leavening agent and 7 g of salt, mix well and knead into dough.

[0045] S5: Using a single fermentation process, place the kneaded dough in a proofing box with 50% humidity and 30℃ and ferment for 2 hours;

[0046] S6: Divide the fermented dough into 180g portions, knead and round them, then shape them into round naan dough. Use a naan poke to evenly poke through the naan dough to expel the internal gas and then stamp it.

[0047] S7: Place the naan dough on a naan tray and bake in an oven or tandoor oven at 230°C (340°F) for 16 minutes, or until the surface of the naan turns golden brown.

[0048] Create a flowchart as follows Figure 1 As shown.

[0049] The *Lactobacillus rhamnosus* (Minsheng Zhongke Jiayi (Shandong) Biotechnology Co., Ltd.), *Lactobacillus casei* (Minsheng Zhongke Jiayi (Shandong) Biotechnology Co., Ltd.), and Xiangba powder used in this invention are derived from commercially available single live bacteria preparations (Angel Yeast Co., Ltd.). *Lactobacillus plantarum*, *Saccharomyces cerevisiae*, and *Pediococcus pentosaceus* were isolated in this invention and then freeze-dried into freeze-dried powders for identification and subsequent experiments. After identification (by Xinjiang Youkang Biotechnology Co., Ltd.) and sequence comparison, they were named freeze-dried *Lactobacillus plantarum*, freeze-dried *Saccharomyces cerevisiae*, and freeze-dried *Pediococcus pentosaceus*. The viable counts of the six substances were also identified, with the viable count of the freeze-dried *Lactobacillus plantarum* not less than 1 × 10⁻⁶. 11 CFU / g, viable count of Saccharomyces cerevisiae not less than 1×10⁻⁶ 11 The cfu / g of lyophilized Pediococcus pentosaceus powder is not less than 1×10⁻⁶. 11 The cfu / g of Lactobacillus rhamnosus powder should have a viable count of not less than 1×10⁻⁶. 10 The cfu / g of the Lactobacillus casei powder is not less than 1×10⁻⁶. 10 The cfu / g of Xiangba powder is not less than 1×10⁻⁶. 10 cfu / g.

[0050] Example 2

[0051] This embodiment provides a compound leavening agent that enhances the gas retention, accelerates fermentation, and adds aroma to dough. The only difference from Embodiment 1 is that the compound leavening agent that enhances the gas retention, accelerates fermentation, and adds aroma to dough is composed of freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosaceus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder in a weight ratio of 1:1:2:3:3:2.

[0052] This embodiment also provides naan prepared using the above-mentioned compound leavening agent that enhances the gas retention, accelerates fermentation, and increases aroma of dough. The preparation method of the naan is the same as in Embodiment 1.

[0053] Example 3

[0054] This embodiment provides a compound leavening agent that enhances the gas retention of dough, promotes rapid fermentation, and adds aroma. The only difference from Embodiment 1 is that the compound leavening agent that enhances the gas retention of dough, promotes rapid fermentation, and adds aroma is composed of freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosaceus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder in a weight ratio of 3:1:3:1:2:2.

[0055] This embodiment also provides naan prepared using the above-mentioned compound leavening agent that enhances the gas retention, accelerates fermentation, and increases aroma of dough. The preparation method of the naan is the same as in Embodiment 1.

[0056] Example 4

[0057] This embodiment provides a compound leavening agent that enhances the gas retention of dough, promotes rapid fermentation, and adds aroma. The only difference from Embodiment 1 is that the compound leavening agent that enhances the gas retention of dough, promotes rapid fermentation, and adds aroma is composed of freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosaceus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder in a weight ratio of 1:2:3:3:2:1.

[0058] This embodiment also provides naan prepared using the above-mentioned compound leavening agent that enhances the gas retention, accelerates fermentation, and increases aroma of dough. The preparation method of the naan is the same as in Embodiment 1.

[0059] Example 5

[0060] This embodiment provides a compound leavening agent that enhances the gas retention of dough, promotes rapid fermentation, and adds aroma. The only difference from Embodiment 1 is that the compound leavening agent that enhances the gas retention of dough, promotes rapid fermentation, and adds aroma is composed of freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosaceus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder in a weight ratio of 3:2:1:3:1:2.

[0061] This embodiment also provides naan prepared using the above-mentioned compound leavening agent that enhances the gas retention, accelerates fermentation, and increases aroma of dough. The preparation method of the naan is the same as in Embodiment 1.

[0062] Example 6

[0063] This embodiment provides a compound leavening agent that enhances the gas retention, accelerates fermentation, and adds aroma to dough. The only difference from Embodiment 1 is that the compound leavening agent that enhances the gas retention, accelerates fermentation, and adds aroma to dough is composed of freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosaceus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder in a weight ratio of 1:2:1:2:3:3.

[0064] This embodiment also provides naan prepared using the above-mentioned compound leavening agent that enhances the gas retention, accelerates fermentation, and increases aroma of dough. The preparation method of the naan is the same as in Embodiment 1.

[0065] Example 7

[0066] This embodiment provides a compound leavening agent that enhances the gas retention, accelerates fermentation, and adds aroma to dough. The only difference from Embodiment 1 is that the compound leavening agent that enhances the gas retention, accelerates fermentation, and adds aroma to dough is composed of freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosaceus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder in a weight ratio of 3:3:1:2:2:1.

[0067] This embodiment also provides naan prepared using the above-mentioned compound leavening agent that enhances the gas retention, accelerates fermentation, and increases aroma of dough. The preparation method of the naan is the same as in Embodiment 1.

[0068] Comparative Example 1: This comparative example provides a single-strain naan starter, which differs from Example 1 only in that the single-strain naan starter is a commercial yeast (used at 3% of the amount of flour used).

[0069] Comparative Example 2: This comparative example provides a single-strain starter culture, which differs from Example 2 only in that the single-strain naan starter culture is brewing yeast powder (the amount used is 3% of the amount of flour used).

[0070] Comparative Example 3: This comparative example provides a single-strain starter culture, which differs from Example 3 only in that the single-strain naan starter culture is a freeze-dried Lactobacillus plantarum (the amount used is 3% of the amount of flour used).

[0071] Comparative Example 4: This comparative example provides a single-strain starter culture, which differs from Example 4 only in that the single-strain naan starter culture is a freeze-dried Pediococcus pentosaceus (the amount used is 3% of the amount of flour used).

[0072] Comparative Example 5: This comparative example provides a single-strain starter culture, which differs from Example 5 only in that the single-strain naan starter culture is Lactobacillus rhamnosus (the amount used is 3% of the amount of flour used).

[0073] Comparative Example 6: This comparative example provides a single-strain starter culture, which differs from Example 6 only in that the single-strain naan starter culture is Lactobacillus casei (used at 3% of the amount of flour used).

[0074] Comparative Example 7: This comparative example provides a single-strain starter culture, which differs from Example 7 only in that the single-strain naan starter culture is Xiangba powder (the amount used is 3% of the amount of flour used).

[0075] Example 8

[0076] Examples 1-7 were sequentially numbered as groups 1-7 or N1-N7, and comparative examples 1-7 were sequentially numbered as groups CK, NJ, ZW, WT, SL, GL, and XB. The naan breads prepared from different strain combinations were tested for fermentability, textural properties, sensory evaluation, and flavor compounds, among other food-related characteristics. The optimal strain ratio combination was selected based on the sensory evaluation results.

[0077] 1. Fermentation Characteristics Determination of Example and Comparative Naan

[0078] According to the data in Table 1, there were significant differences (P < 0.05) in the characteristics of fermented dough produced by the compound leavening agents, specifically in the changes in maximum height, time to void formation, total release volume, maximum gas release height, and retention coefficient R during fermentation. The retention coefficient R of the sourdough fermented in the example was significantly higher than that in the comparative example. The R value reflects the gas-holding capacity of the dough. High-quality dough usually has a strong and stable gluten network structure, which can better retain gas, thereby improving the texture of naan. During fermentation, the maximum fermentation height of dough in groups 7 and 5 was significantly better than that of other groups (P < 0.05), while the fermentation height of dough in groups ZW, WT, and SL was the lowest. The higher the maximum fermentation height of the dough, the larger its volume will be, and the maximum gas release height and time will also increase accordingly. The maximum gas release time, total release volume, and maximum gas release height of sourdough in groups 5, 6, and 7 were all significantly higher than those in the comparative example.

[0079] Table 1. Fermentation characteristics data of different embodiments and comparative examples

[0080]

[0081] The texture analysis of the naan is shown in Table 2. Compared with the control group (CK), the naan fermented with the compound leavening agent showed reduced hardness, stickiness, and chewiness, increased elasticity, and a softer texture. The texture of the naan in all groups showed varying degrees of change with significant differences (P < 0.05). Table 2 shows that the hardness of the naan in Examples 1-7 (groups 1-7) ranged from 54.26 to 220.33 N. The hardness of the naan in Comparative Examples 1 and 7 (CK and XB groups) ranged from 58.07 to 289.60 N. The hardness of the naan in the Examples was significantly lower than that in the Comparative Examples. The differences in adhesiveness and cohesion among the samples were not significant.

[0082] Table 2. Naan Texture Index Data

[0083]

[0084] 2. Sensory evaluation of naan in the examples and comparative examples

[0085] The sensory evaluation of the naan is shown in Table 3. Compared with the control group, the naan fermented with the compound leavening agent showed improved crispness and chewiness, and the flavor of the naan was also enhanced. Groups 1 and 3 had the best sensory evaluations. Figure 2 As can be seen from the sensory evaluation radar chart, groups N1 and N3 (Examples 1 and 3) have a wider coverage area, and their scores in core sensory dimensions such as appearance, color, flavor, and crispness are all at a high level, with their total sensory scores closer to the upper limit. Therefore, N1 and N3 have the best sensory evaluation.

[0086] Table 3 Sensory Evaluation Scores of Naan

[0087]

[0088] 3. Detection of naan flavor compounds in the examples and comparative examples

[0089] Table 4. Detection results of flavor compounds in the naan from the examples.

[0090]

[0091]

[0092] Table 5. Results of flavor compound detection in comparative naan bread

[0093]

[0094]

[0095] 4. Detection of volatile components in naan bread in examples and comparative cases

[0096] Based on gas phase ion mobility spectrometry (GC-IMS), 82 monomeric or dimeric volatile organic compounds (VOCs) were identified from the naan breads of the examples and comparative samples after comparison with the NIST and IMS databases (Tables 4 and 5). The carbon chains of the identified VOCs were generally concentrated between C3 and C10, including 16 alcohols, 16 esters, 15 aldehydes, 6 ketones, 3 furans, 2 amines, 4 acids, and 6 other types. Aldehydes had the highest content, followed by esters and alcohols. As shown in Tables 4 and 5, alcohols are the main VOCs in naan bread fermented with the compound leavening agent.

[0097] Based on the aroma characteristics of naan fermented with a compound starter obtained by HS-GC-IMS, fingerprint spectra of naan from the examples and comparative examples were constructed, and the results are as follows. Figure 3 As shown, based on the regional feature analysis of the volatile component fingerprint heatmap, the following can be identified: The red area contains 36 volatile compounds, including 3-methyl-2-butenal-M, 3-methylbutyl formate, L-carvone, and 3-methyl-1-butanol. These are flavor compounds shared by the compound bacterial groups (3, 4, 5, 6, 7) in the examples and the single strain groups (CK, NJ, XB) in the comparative examples, reflecting the common basic flavor of the naan from different groups. The yellow area contains 15 components, including dihydro-2(3H)-furanone, 1-heptanol, hexanilide, and 3-methyl-2-butenal-D. These are characteristic flavor compounds of compound bacterial groups 1 and 2, and are found in naan produced using this type of fermentation method. The white area contains 24 flavor compounds, including 3-methylthiopropanal-D, 1-pentanol, methylpyrazine, and (E)-2-octenal, which are relatively abundant in the single strain groups (XB, ZW, SL, GL, WT) in the comparative example and are the core flavor contributors of single-strain fermented naan; the green area contains 3-methylthiopropanal, which is a common characteristic flavor of groups XB and GL, and isopropyl 2-methylbutyrate, which is a unique characteristic flavor of group XB; at the same time, 10 flavor compounds, including 3-methylthiopropanal, 2-methyl-1-pentanol, and (E)-3-hexen-1-ol, are characteristic flavor compounds of the compound strain group 2 naan in the example.

[0098] from Figure 3It was also found that 36 flavor compounds, including 3-methyl-2-butenal-M, 3-methylbutyl formate, L-carvone, 3-methyl-1-butanol, 1-heptanal, and 1-propanethiol-D, in the red area are volatile compounds common to the compound bacterial groups (groups 3, 4, 5, 6, and 7) of the examples and the single strain groups (groups CK, NJ, and XB) of the comparative examples. The yellow area contained 15 characteristic flavor compounds of compound bacteria 1 and 2, including dihydro-2(3H)-furanone, 1-heptanol, hexanilide, and 3-methyl-2-butenal-D. The white area contained 24 flavor compounds, including 3-methylthiopropanal-D, 1-pentanol, methylpyrazine, 2-methyl-2-propenal, isoamyl valerate, and (E)-2-octenal, which had relatively high contents in the single strain groups (XB, ZW, SL, GL, and WT) of the comparative examples. The green area contained 3-methylthiopropanal, which was a characteristic flavor of groups XB and GL. Isopropyl 2-methylbutyrate is a characteristic flavor of group XB. Ten flavor compounds, including 3-methylthiopropanal, 2-methyl-1-pentanol, (E)-3-hexen-1-ol, and 2-heptanol, are characteristic flavors of group 2 of the compound bacteria in the example.

[0099] like Figure 4 As shown, the areas marked in Examples 1 to 5 are significantly different from the comparative examples, exhibiting a clear difference in volatile components and a richer aroma and flavor.

[0100] like Figure 5 As shown, the dimensions of this three-dimensional spectrum are defined as follows: the y-axis represents the retention time of a substance in gas chromatography (GC) (unit: s); the x-axis represents the ion migration time of a substance in ion mobility spectra (normalized); and the signal intensity corresponding to the z-axis can be used to characterize the relative content of the corresponding substance in the sample. From the signal distribution of the spectrum, it can be seen that there are significant differences in signal intensity among different samples. Specifically, the signal intensity of the region marked by the black circle in groups 1, 3, and XB is significantly higher than that in other groups, indicating that the relative content of the flavor compound corresponding to this region in these three groups is higher than in the other groups.

[0101] PLS-DA loading diagram of volatile components in naan ( Figure 6 The cumulative explanation rate of principal components 1 (56.5%) and 2 (22.5%) reached 79%, effectively reflecting the contribution of components to the differences between groups. In the figure, components such as 3-methyl-2-butenal-D, 3-methyl-1-butanol-D, and 2-methyl-2-propanol are far from the origin and are key volatile components driving the flavor differences between different naan groups. The results show that the cumulative contribution rate of principal components PC1 and PC2 reached 79.0%, covering the main characteristic information of naan.

[0102] like Figure 6 and Figure 7As shown, PCA and PLS-DA analyses were performed on the volatile components of Examples 1-7 and Comparative Examples 1-7. The figures clearly distinguish between the examples and the comparative examples. The results show that the first principal component (component 1) of the PLS-DA model explains 56% of the total variance, and the second principal component (component 2) explains 9.4% of the total variance, with a cumulative explanation rate of 65.4%, which can effectively reflect the main differences in the volatile components of naan. From the sample distribution of the score plot, it can be seen that the samples of the single yeast fermentation group, the compound fermentation group, and the control group show a clear spatial separation trend, indicating that there are significant differences in the flavor components of naan under the three fermentation methods.

[0103] Depend on Figure 8 As shown: The characteristic aroma substances of naan fermented with compound starter include 2-methyl-2-propanol, 3-methyl-2-butenal-D, 3-methyl-1-butanol-D, propionic acid, furfuryl alcohol, 5-methyl sulphurine, ethyl acetate, methyl acetate, 1-penten-3-one, 2-butanol, 3-methylbutanal, 2-ethyl furan, etc., with flavors of fruit, alcohol, nuts, chocolate, grain, malt, and sourness.

[0104] The variable importance for the projection (VIP) in orthogonal partial least squares discriminant analysis (PLS-DA) was used to identify the differentially volatile flavor compounds in naan bread fermented with different starter cultures (VIP>1). Figure 8 It is known that the analysis results of volatile components (VIP) in Examples 1-7 (groups 1, 2, 3, 4, 5, 6, 7) and Comparative Examples 1-7 (groups CK, NJ, ZW, WT, SL, GL, XB) show that 10 volatile substances with VIP > 1 were screened out from 14 groups of samples. Figure 8 The results also showed that the VIP values ​​of the main flavor compounds, such as 2-methyl-2-propanol, 2-methylbutanal, 3-methyl-1-butanol, 2-hexanol and ethyl acetate, were all greater than 3, indicating that these compounds are key differentiating components affecting the flavor characteristics of naan.

[0105] like Figure 9 The results showed that alcohols were the main volatile components of the compound bacteria naan, accounting for 31% to 40% of the total content. Alcohols are key contributors to the aroma of food, thus this naan has a richer aroma. Secondly, esters (which impart fruity and ester aromas) and flavonoids (which are associated with delicate plant aromas and flavor stability) were relatively abundant. Together with alcohols, they enhanced the richness and harmony of the flavor of the compound bacteria naan, while retaining the mellow traditional flavor unique to sourdough fermentation.

[0106] The naan produced by the method of this invention uses a compound leavening agent for fermentation, which not only preserves the rich, traditional flavor unique to sourdough fermentation but also significantly improves the sensory quality of the naan. Specifically, it results in a softer, more elastic texture, increased surface gloss, and a more uniform and natural color. Furthermore, this method shortens the fermentation time and imparts a unique aroma to the sourdough naan, thereby enhancing the flavor of the final product.

[0107] In summary, the composite leavening agent of this invention comprises freeze-dried *Lactobacillus plantarum*, freeze-dried *Saccharomyces cerevisiae*, freeze-dried *Pediococcus pentosaceus*, *Lactobacillus rhamnosus*, *Lactobacillus casei*, and spice powder. The optimal mass ratio is 2:1:3:2:3:1 or 3:1:3:1:2:2. Naan prepared under this ratio exhibits better sensory characteristics, specifically: a softer and more elastic texture, improved surface gloss, and a more uniform and natural color. Furthermore, this method can shorten fermentation time and impart a unique aroma to the fermented naan, thereby enhancing the flavor of the final product.

[0108] The above-described embodiments are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A gas-retaining and aroma-enhancing rapid fermentation compound starter for naan bread, characterized in that, The components of the compound fermentation agent include freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder.

2. A method for preparing a gas-retaining and aroma-enhancing rapid fermentation compound starter for naan bread, characterized in that, Specifically, the following steps are included: S1: Five representative sourdough samples from Xinjiang Uygur Autonomous Region were isolated and identified, and brewer's yeast, lactobacillus plantarum and Pediococcus pentosaceus were screened out; S2: After freeze-drying brewer's yeast, lactobacillus plantarum and Pediococcus pentosus, they are combined with commercially available lactobacillus rhamnosus, lactobacillus casei and flavoring yeast to optimize the strain ratio. After optimization, they are mixed according to the mass ratio to prepare a compound fermentation agent.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder is 1~3∶1~3∶1~3∶1~3∶1~3∶1~3∶1~3.

4. The preparation method according to claim 3, characterized in that, The mass ratio of the freeze-dried Lactobacillus plantarum, freeze-dried Saccharomyces cerevisiae, freeze-dried Pediococcus pentosus, Lactobacillus rhamnosus, Lactobacillus casei, and Xiangba powder is 2:1:3:2:3:1 or 3:1:3:1:2:

2.

5. The application of the compound starter culture obtained by the preparation method of claim 2 in the fermentation of naan bread.

6. The application according to claim 5, characterized in that, The specific steps for fermenting and making naan are as follows: S1: Weigh the flour, add the corresponding amount of water according to the flour's water absorption rate, then add the compound leavening agent and salt, mix well and knead into a dough; S2: Use a single fermentation process to ferment the kneaded dough for 1.5~2 hours; S3: Divide the fermented dough into 150~200g portions, shape them into round naan dough, and deflate and stamp them. S4: Bake the naan dough at a temperature of 220~230℃ for 15~18 minutes until the surface of the naan turns golden brown.

7. The application according to claim 6, characterized in that, The mass ratio of flour, compound leavening agent and salt is 1200~1500:36~45:7~9.

8. The application according to claim 6, characterized in that, The fermentation conditions are: humidity 50%~55% and temperature 30~35℃.

9. The application according to claim 5, characterized in that, The compound leavening agent is used to reduce the hardness of naan, shorten the fermentation time, and enhance the flavor and texture of naan.

10. The application according to claim 9, characterized in that, The flavors include, but are not limited to, alcohols, esters, aldehydes, ketones, furans, pyrazines, and amines.

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