Fermentation method for improving nutritional value and flavor characteristics of chickpea tempeh

Abstract

The invention provides a method for preparing chickpea tempeh by fermenting chickpeas. The method comprises the following steps: sprouting, introducing lactobacillus plantarum to carry out first fermentation, introducing rhizopus oryzae to carry out second fermentation, and the like. According to the method provided by the embodiment of the invention, the chickpea tempeh is endowed with richer flavor and better taste while functional components such as protein and isoflavone of the chickpea are improved, so that the chickpea tempeh has more excellent sensory quality and higher nutritional value.

Description

Technical Field

[0001] The present application relates to the technical field of food processing, and particularly relates to a fermentation method for enhancing the nutritional value and flavor characteristics of chickpea tempeh. Background Art

[0002] Chickpea (Cicer arietinum L.) is a kind of legume rich in plant protein, dietary fiber, isoflavones and various bioactive substances, and has important nutritional value and a wide range of edible bases globally. However, chickpeas contain relatively high levels of antinutritional factors, such as protease inhibitors, phytic acid and oligosaccharides, etc., and these components will affect the digestion and absorption of its nutrients. In addition, chickpeas have a relatively light flavor and a hard texture, and the taste is poor after direct consumption or simple cooking, which limits its scope of application.

[0003] Tempeh is a traditional fermented food originating from Indonesia. It has been found that tempeh fermentation can effectively improve the digestibility of plant protein and improve the flavor and texture of legume foods. Tempeh is usually prepared from legumes such as soybeans and black beans, and the research focus is mostly on improving the taste, enhancing the flavor and optimizing the fermentation process. In the prior art, the fishy smell of tempeh is often reduced, the nutritional value is enhanced and the texture is improved by adjusting the strains, fermentation conditions or adding auxiliary materials. For example, the invention patent TW109208225 enhances the protein utilization rate of tempeh by fermenting the soybean dregs and legumes, while reducing the waste of soybean dregs; the invention patent CN107801916A tries to add edible fungi to optimize the fermentation flavor and structure; the invention patent CN107874121A improves the tempeh flavor and reduces the tempeh cooking time by seasoning the soybeans before fermentation.

[0004] Chickpeas are rich in high-quality protein, dietary fiber and various bioactive components. Applying the tempeh fermentation process to chickpeas is expected to improve its nutritional value while endowing it with better flavor and texture. However, there are few reports on preparing tempeh from chickpeas at present, and there are significant differences in the protein structure and flavor characteristics between chickpeas and the soybean raw materials in tempeh fermentation. Therefore, it is still necessary to explore a fermentation method suitable for chickpeas to effectively enhance the nutritional value and flavor characteristics of chickpea tempeh. Summary of the Invention

[0005] The present application solves at least one of the problems of the related art from the following aspects.

[0006] To this end, an embodiment of the present application provides a method for fermenting chickpeas, including: placing chickpeas under conditions suitable for germination to germinate them, obtaining germinated chickpeas; subjecting the germinated chickpeas to a cooking process to obtain cooked chickpeas; introducing one of Lactobacillus plantarum and Rhizopus oryzae into the cooked chickpeas to perform a first fermentation on them, obtaining first-fermented chickpeas; and introducing the other of Lactobacillus plantarum and Rhizopus oryzae into the first-fermented chickpeas to perform a second fermentation on them, obtaining second-fermented chickpeas.

[0007] In the embodiment of the present application, by placing chickpeas under conditions suitable for germination to germinate the chickpeas, and using the obtained germinated chickpeas as subsequent fermentation materials. In some embodiments, the conditions suitable for germination include: the germination temperature is 15 - 37°C, preferably 20 - 30°C, more preferably 25°C; and the relative humidity for germination is 50% - 90%, preferably 65% - 75%, more preferably 80%. In some embodiments, the chickpeas are placed under the germination conditions for 6 - 96h, preferably 12 - 72h, more preferably 24 - 72h to germinate them. In some specific embodiments, the chickpeas, preferably the pre-germinated chickpeas, can be placed in an environment of 25°C and a relative humidity of 80% to germinate. Water is sprayed once every 6h and changed once every 12h during germination, and germination lasts for 12 - 72h to obtain germinated chickpeas. The method proposed in the embodiment of the present application performs a germination treatment on chickpeas before fermentation, significantly increasing the contents of essential amino acids, total phenols, total flavonoids, and isoflavones, providing richer precursor substances for fermentation, and bringing better nutritional value and flavor characteristics. By combining the germination treatment with secondary fermentation, the nutritional value and flavor of chickpea tempeh are significantly improved.

[0008] In some embodiments, before germination, the method further includes: soaking the chickpeas in water for pre-germination treatment. In some embodiments, the chickpeas can be soaked in water at 20 - 25°C for 8 - 12h for pre-germination treatment. For example, after cleaning the chickpeas, they can be soaked at 25°C for 12h for pre-germination.

[0009] In some embodiments, before fermentation, the germinated chickpeas can be subjected to a cooking process. In some embodiments, the cooking process includes: boiling the germinated chickpeas in water and then peeling them to obtain peeled chickpeas; and steaming the peeled chickpeas to obtain the cooked chickpeas. In some specific embodiments, the cooking process can be, for example: boiling the germinated chickpeas in boiling water for 5min, peeling them, and then steaming for 20min to obtain cooked chickpeas.

[0010] In some embodiments, the fermentation may specifically include: introducing Lactobacillus plantarum into the cooked chickpeas for the first fermentation to obtain the first fermented chickpeas; and introducing Rhizopus oryzae into the first fermented chickpeas for the second fermentation to obtain the second fermented chickpeas. The method provided in the embodiments of the present application includes two fermentations of lactic acid bacteria and Rhizopus oryzae based on germinated chickpeas. Compared with using the two bacteria for separate single fermentations, the synergistic effect of the two can effectively reduce anti-nutritional factors, improve the flavor, and form excellent texture and flavor substances, significantly improving the nutritional value, flavor and digestibility of tempeh.

[0011] In some embodiments, the first fermentation specifically includes: introducing 2%-10% (v / v), preferably 3%-5% (v / v) of Lactobacillus plantarum into the cooked chickpeas, wherein the concentration of Lactobacillus plantarum is 10 4 -10 10 CFU / mL, preferably 10 6 -10 9 CFU / mL, more preferably 10 8 CFU / mL; and fermenting the cooked chickpeas introduced with Lactobacillus plantarum under conditions suitable for the fermentation of Lactobacillus plantarum. In some embodiments, the conditions suitable for the fermentation of Lactobacillus plantarum include: fermenting at 20-40°C, preferably 37°C for 4-10 h, preferably 5-8 h, more preferably 6 h. In some specific embodiments, 3%-5% (v / v) of Lactobacillus plantarum suspension can be inoculated into the cooked chickpeas and statically cultured at 37°C for 6 h to obtain the first fermented chickpeas fermented by Lactobacillus plantarum.

[0012] In some embodiments, the second fermentation specifically includes: introducing 0.1%-2% (w / w), preferably 0.2% (w / w) of Rhizopus oryzae into the first fermented chickpeas; and fermenting the first fermented chickpeas introduced with Rhizopus oryzae under conditions suitable for the fermentation of Rhizopus oryzae. In some embodiments, the conditions suitable for the fermentation of Rhizopus oryzae include: fermenting at 20-40°C, preferably 37°C for 10-40 h, preferably 12-36 h, more preferably 24-32 h. In some specific embodiments, 0.2% (w / w) of Rhizopus oryzae can be inoculated into the first fermented chickpeas and fermented at a constant temperature of 37°C in an incubator for 24-32 h to obtain the second fermented chickpeas, i.e., tempeh.

[0013] In some embodiments, before performing the second fermentation, the Lactobacillus plantarum in the first fermentation is inactivated. For example, the chickpeas in the first fermentation can be heated in a boiling water bath for 15 min to inactivate the Lactobacillus plantarum. In some embodiments, after inactivating the Lactobacillus plantarum in the first fermentation and before performing the second fermentation, the method further includes: cooling the inactivated chickpeas in the first fermentation to room temperature, and performing the subsequent second fermentation based on the cooled chickpeas in the first fermentation.

[0014] The method for preparing tempeh from chickpeas proposed in the embodiments of the present application effectively improves the protein digestibility, antioxidant activity and flavor of chickpeas through the synergistic effects of germination, lactic acid bacteria fermentation and Rhizopus oryzae fermentation, improves the functionality and sensory quality of tempeh, and can be widely applied to the development of high-protein plant-based foods, functional fermented foods and vegetarian products, having good market application prospects.

[0015] The embodiments of the present application also provide a kind of chickpea tempeh, which is prepared according to the method described in any of the above embodiments.

[0016] The embodiments of the present application achieve the following beneficial effects:

[0017] The chickpea fermentation process proposed in the present application effectively improves the nutritional value of chickpeas and their processing characteristics by performing germination treatment before fermentation, such as promoting the activity of endogenous enzymes in chickpeas, increasing the degree of protein hydrolysis, increasing the content of bioactive substances such as free amino acids, polypeptides and isoflavones, and at the same time reducing anti-nutritional factors, such as reducing phytic acid and improving the bioavailability of minerals. In addition, by using Lactobacillus plantarum and Rhizopus oryzae to perform secondary fermentation on the germinated chickpeas, the synergistic effect of the two not only promotes the degradation of proteins and carbohydrates, enhances the formation of flavor substances, but also improves the safety and functionality of the fermentation products. The method proposed in the embodiments of the present application improves the functional components such as chickpea protein and isoflavones, while endowing it with richer flavor and better taste, making the chickpea tempeh have more excellent sensory quality and higher nutritional value. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic flow chart of the method for preparing chickpea tempeh according to the embodiments of the present application;

[0020] Figure 2 Shows the changes in the protein, soluble protein, and polypeptide contents of chickpeas after being treated with different germination times in the embodiments of the present application;

[0021] Figure 3 Shows different tempeh morphologies of chickpeas according to the embodiments of the present application;

[0022] Figure 4 Shows the sensory scores of different chickpea tempehs according to the embodiments of the present application, including the radar chart of the overall flavor evaluation (A) and the radar chart of the aroma evaluation (B) of chickpea tempeh. Detailed implementation manners

[0023] The present invention will be further described in detail below in conjunction with the specific implementation manners. The given embodiments are only for clarifying the present invention and do not limit the scope of the present invention. The following provided embodiments can be used as a guide for those of ordinary skill in the art to make further improvements and do not limit the present invention in any way.

[0024] The experimental methods in the following embodiments are all conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in this field or according to the product specifications. The materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0025] Unless otherwise specified, the quantitative analysis tests in the following embodiments are all set with three repeated experiments, and the results are averaged.

[0026] Example 1

[0027] This example proposes a method for preparing chickpea tempeh, referring to Figure 1 , and the method specifically includes:

[0028] 1) Select mature, plump, and undamaged chickpeas, wash them clean, and soak them at 25°C for 12 h to obtain soaked chickpeas.

[0029] 2) Place the soaked chickpeas obtained in step 1) in an environment of 25°C and a relative humidity of 80% for germination. Spray water once every 6 h and change the water once every 12 h during germination. Germinate for 12 - 72 h to obtain germinated chickpeas.

[0030] 3) Take the germinated chickpeas obtained in step 2), boil them in boiling water for 5 min, remove the skin, and steam them for 20 min to obtain steamed chickpeas, and naturally cool them to room temperature.

[0031] 4) Take the cooled chickpeas obtained in step 3), inoculate them with a 3% - 5% (v / v) suspension of Lactobacillus plantarum, and statically culture them at 37°C for 6 h to obtain lactic acid bacteria-fermented chickpeas.

[0032] 5) Heat the Lactobacillus-fermented chickpeas obtained in step 4) in a boiling water bath for 15 min to inactivate the Lactobacillus, obtaining inactivated fermented chickpeas.

[0033] 6) Take the inactivated fermented chickpeas obtained in step 5), cool them to room temperature, inoculate with 0.2% (w / w) Rhizopus oryzae, and mix thoroughly to obtain inoculated chickpeas.

[0034] 7) Put the inoculated chickpeas obtained in step 6) into a sterile self-sealing bag, puncture holes with a sterilized needle (the hole spacing is about 1 cm), flatten them, and slightly compact them to obtain chickpeas to be fermented.

[0035] 8) Take the chickpeas to be fermented obtained in step 7), place them in a mold incubator and ferment at a constant temperature of 37 °C for 24 - 32 h to obtain tempeh of fermented chickpeas.

[0036] Example 2

[0037] In this example, by germinating chickpeas for different times, the changes in the protein, soluble protein, polypeptide content, and amino acid composition of chickpeas at different germination times were detected. The specific method is as follows:

[0038] 1) Select mature, plump, and undamaged chickpeas, wash them clean, and soak them in pure water at 25 °C for 12 h to obtain soaked chickpeas.

[0039] 2) Cultivate the soaked chickpeas obtained in step 1) under the conditions of 25 °C and a relative humidity of 80%, spray humidify them once every 6 h during the period, change the water once every 12 h, and continuously germinate for 0 - 72 h.

[0040] 3) Take the germinated chickpeas every 12 h as an experimental group for component determination, and take the non-germinated (i.e., 0 h) chickpeas as a control group.

[0041] 2.1 Determination of amino acid composition and determination of amino acid score (AAS)

[0042] Extraction of samples: Accurately weigh 0.2000 g of the freeze-dried powder of each sample to be measured into a 15 mL centrifuge tube, add 8 mL of water, extract by ultrasonic oscillation for 30 min, take 1.5 mL of the extract, centrifuge at 12000 r / min for 30 min, and take the supernatant for standby. Pipette 300 μL of the sample supernatant, add 150 μL of 0.1 mmol / L phenyl isothiocyanate, 150 μL of 1 mol / L triethylamine, vortex mix and react at room temperature for 1 h, add 600 μL of n-hexane to extract impurities, and centrifuge at 12000 r / min for 5 min. Discard the upper organic phase, and take the lower clear liquid into a liquid phase injection vial for determination.

[0043] HPLC conditions: The chromatographic column is Shim-pack VP-ODS 5μm 150×4.6mm, the column temperature is 36°C, the flow rate is 1 mL / min, the detection wavelength is 254 nm, and the injection volume is 4 μL. Mobile phase A is 0.1 mol / L sodium acetate (pH 6.50): acetonitrile = 93:7, and mobile phase B is acetonitrile: water = 4:1. A gradient elution program is adopted. Taking phase B as an example, from 0 to 14 min, it linearly changes from 0% to 25%; from 14 to 20 min, it linearly changes from 25% to 32%; from 20 to 22 min, it remains at 100%; from 22 to 30 min, it remains at 0%.

[0044] The amino acid score (AAS) is calculated according to the following formula:

[0045]

[0046] In the formula, AAS is the amino acid score, %; m·EAA is the content of a certain essential amino acid in the protein to be measured, mg / g; m··EAA is the content of the same essential amino acid in the standard protein, mg / g; the FAO / WHO recommended pattern is used as the standard protein.

[0047] The determination results of the amino acid composition and amino acid score (AAS) of each sample are shown in Table 1 and Table 2.

[0048] 2.2 Determination of isoflavone monomer content

[0049] Basically referring to GB / T 23788-2009 "Determination Method of Soybean Isoflavones in Health Foods", with slight modifications.

[0050] Extraction of the sample: Weigh 1.0 g of the sample into a 50 mL centrifuge tube, add 20 mL of the extraction agent 70% ethanol solution according to a ratio of 1:20, and soak overnight. Extract ultrasonically for 20 min, filter through a 0.22 μm filter membrane, and the supernatant is used for HPLC analysis.

[0051] High-performance liquid chromatography conditions: Chromatographic column: Agilent Poroshell 120EC-C18 chromatographic column (3.0×100 mm, 2.7 μm); Flow rate: 0.8 mL / min; Injection volume: 20 μL; Column temperature: 40°C; Detection wavelength: 254 nm; Mobile phase A: 5% acetic acid aqueous solution; Mobile phase B: 45% methanol aqueous solution. High-performance liquid chromatography operating conditions: From 0 to 5 min, 65% of phase B; from 5 to 23 min, 100% of phase B; from 23 to 29 min, 65% of phase B.

[0052] The determination results of the isoflavone monomer content are shown in Table 3.

[0053] 2.3 Determination of crude protein, soluble protein and polypeptide content

[0054] The crude protein content was determined by the Kjeldahl method with reference to GB 5009.5—2016 Determination of Protein in Foods.

[0055] The content of soluble protein was determined by the Coomassie brilliant blue G-250 dye method. Accurately weigh 0.1000 g of the sample freeze-dried powder, add 5 mL of PBS buffer, extract it in a shaker at 28 °C for 1 h, centrifuge at 4 °C and 10,000 r / min for 15 min, and take the supernatant. Mix 1 mL of the supernatant with 5 mL of Coomassie brilliant blue G-250 dye, react at room temperature for 3 - 5 min, and then measure the absorbance at 595 nm. According to the standard curve y = 1.9085x + 0.4526 (R 2 = 0.9992) for bovine serum albumin (BSA) determination, calculate the soluble protein content of the sample, and the final result is expressed as mg / g DW.

[0056] The polypeptide content was determined by the Folin-phenol method. The sample extraction method was the same as that for the determination of soluble protein content. Take 1 mL of the sample solution and add 5 mL of reagent A (volume ratio A1:A2 = 50:1, A1 is obtained by dissolving 6 g of anhydrous sodium carbonate + 2.4 g of sodium hydroxide in 300 mL of deionized water, and A2 is obtained by dissolving 0.5 g of copper sulfate pentahydrate in 100 ml of 1% potassium sodium tartrate), mix well and let it stand at 20 - 25 °C for 10 min, then add 0.5 mL of reagent B (Folin-phenol reagent) and mix immediately, let it stand at 20 - 25 °C for 30 min, use 1 mL of water instead of the sample as a blank control at 500 nm, and measure the OD value. According to the standard curve y = 0.9318x + 0.0433 (R 2 = 0.9997), calculate the protein polypeptide concentration of the crude extract sample to be measured.

[0057] The determination results of crude protein, soluble protein and polypeptide content are as Figure 2 shown.

[0058] 2.4 Results

[0059] Figure 2 The protein, soluble protein and polypeptide contents after different germination times of chickpeas are shown, where different lowercase superscript letters in the same row indicate significant differences (P < 0.05). As Figure 2 can be seen, compared with ungerminated chickpeas, the germination treatment significantly increased the contents of crude protein, soluble protein and polypeptide in chickpeas, making chickpea protein more easily digested and absorbed.

[0060] Table 1

[0061]

[0062]

[0063] Note: Different lowercase superscripts in the same row indicate significant differences (P<0.05); "-" indicates not detected.

[0064] Table 2

[0065]

[0066] Note: Different lowercase superscripts in the same row indicate significant differences (P<0.05); "-" indicates not detected.

[0067] Table 1 shows the amino acid composition and content changes of chickpeas after different germination times, and Table 2 shows the main amino acid scores of chickpeas at different germination times. As can be seen from Table 1 and Table 2, compared with ungerminated chickpeas, germination treatment significantly increased the essential amino acids and total amino acids of chickpeas, and significantly increased the content of free amino acids in chickpeas, optimized its nutritional composition, and improved the protein quality. Such an improvement effect was more obvious after 24 - 72 h of germination treatment, and with the extension of germination time, the improvement effect gradually accumulated and enhanced.

[0068] Table 3 below shows the changes in the content of isoflavone monomers in chickpeas after different germination times. As can be seen from Table 3, compared with non-germinated ones, germinated chickpeas showed higher isoflavone content, indicating that germination can significantly increase the isoflavone content of chickpeas. Such an increase was more obvious after 24 - 72 h of germination treatment, and with the extension of germination time, the improvement effect gradually accumulated and enhanced.

[0069] Table 3

[0070]

[0071] Note: Different lowercase superscripts in the same row indicate significant differences (P<0.05); "-" indicates not detected.

[0072] Example 3

[0073] Referring to the germination time in Example 2, in this example, further using germinated chickpeas as materials, two fermentations were carried out using Lactobacillus plantarum and Rhizopus oryzae, and groups without germination treatment and single-strain fermentation only were set as control groups. The specific test methods are as follows:

[0074] 1) Select mature, plump, and undamaged chickpeas, wash them clean, and soak them at 25°C for 12 h to obtain soaked chickpeas.

[0075] 2) The soaked chickpeas obtained in step 1) were germinated in an environment of 25°C and 80% relative humidity. During the germination period, water was sprayed every 6 h and changed every 12 h. After 24 h of germination, germinated chickpeas were obtained, and a non-germinated treatment group was set as a control.

[0076] 3) Take the germinated chickpeas obtained in step 2), boil them in boiling water for 5 min, steam them for 20 min after peeling, and obtain steamed chickpeas, which were naturally cooled to room temperature.

[0077] 4) Take the cooled chickpeas obtained in step 3), inoculate them with a 5% (v / v) suspension of Lactobacillus plantarum (Jiangsu Zishi Micro-Health Biotechnology Co., Ltd., HH-LP57), and statically culture them at 37°C for 6 h to obtain lactic acid bacteria-fermented chickpeas. In addition, a control group without inoculating this lactobacillus was set, and only the fermentation of Rhizopus oryzae in steps 6-8 below was carried out;

[0078] 5) The lactic acid bacteria-fermented chickpeas obtained in step 4) were heated in a boiling water bath for 15 min to inactivate the lactic acid bacteria and obtain inactivated fermented chickpeas.

[0079] 6) Take the inactivated fermented chickpeas obtained in step 5), cool them to room temperature, inoculate them with 0.2% (w / w) Rhizopus oryzae (Luoyang Yishengtang Biotechnology Co., Ltd., Rhizopus oryzae powder, Cat: SC12541031100251), and mix them thoroughly to obtain inoculated chickpeas;

[0080] 7) The inoculated chickpeas obtained in step 6) were put into a sterile self-sealing bag, pricked with a sterilized needle (the hole spacing is about 1 cm), spread out flat, and slightly compacted to obtain chickpeas to be fermented;

[0081] 8) Take the chickpeas to be fermented obtained in step 7), place them in a mold incubator and ferment at a constant temperature of 37°C for 24 h to obtain tempeh fermented chickpeas.

[0082] 3.1 Sensory evaluation

[0083] Before the preference test, 4 sensory evaluators each conducted an aroma sensory evaluation on the tempeh fermented chickpea samples, discussed whether the selected descriptors could comprehensively describe the aroma characteristics of the tempeh fermented chickpeas, and finally summarized the descriptors to determine the final aroma descriptors. Non-experimental samples were used for simulation training, and Panel Check 1.4.2 was used to evaluate the aroma attribute discrimination ability, repeatability, and consistency of the sensory evaluators.

[0084] Preference tests were conducted on the chickpea tempeh in this experiment. The preference tests were carried out by 20 untrained panelists (a total of 20 valid questionnaires were received, 16 females and 4 males, aged between 23 and 40 years old). The sensory characteristics included odor, texture, color, taste and flavor. The panelists were required to score each attribute in the questionnaire (these attributes had been pre-screened by sensory evaluators), with scores ranging from 0 (extremely dislike / extremely low) to 10 (extremely like / extremely high).

[0085] Figure 4 The sensory scores of the chickpea tempeh obtained according to the embodiments of the present application are shown, including the radar chart of the overall flavor evaluation of the chickpea tempeh (A) and the radar chart of the aroma evaluation (B). The sensory scores indicate that the flavor and texture of the twice-fermented germinated chickpea tempeh obtained in the embodiments of the present application are superior to those of the twice-fermented ungerminated chickpea tempeh, the Rhizopus oryzae single-strain fermented germinated chickpea tempeh and the commercially available chickpea tempeh, and it is more competitive in the market, indicating that the germination treatment combined with twice fermentation can significantly improve the flavor of the chickpea tempeh.

[0086] 3.2 The determination method of the amino acid composition and the amino acid score (AAS) is the same as that in part 2.1 of Example 2, and the results are shown in Tables 4 and 5.

[0087] 3.3 The determination method of the isoflavone monomer content is the same as that in part 2.2 of Example 2, and the results are shown in Table 6.

[0088] 3.4 Results

[0089] Figure 3 The morphology of the chickpea tempeh obtained according to the embodiments of the present application is shown, including the overall morphology and the cross-sectional morphology, where from left to right are the germinated chickpea tempeh fermented twice (Lactobacillus plantarum 6h + Rhizopus oryzae 24h) (corresponding to GF24 in Figure 3 ), the ungerminated chickpea tempeh fermented twice (Lactobacillus plantarum 6h + Rhizopus oryzae 24h) (corresponding to NGF in Figure 3 ), the germinated chickpea tempeh fermented only once by Rhizopus oryzae (24h) (corresponding to RGF in Figure 3 ), and the commercially available chickpea tempeh (Shanghai Xinbaokang Food Co., Ltd., Lute Chickpea Tempeh, Cat: SC12531011704279) (corresponding to B0 in Figure 3 ).

[0090] Tables 4 - 6 respectively show the amino acid composition, main amino acid scores, and isoflavone content of chickpea tempeh according to the embodiments of the present application. As can be seen from Tables 4 to 6, compared with single-strain fermentation of chickpeas by lactic acid bacteria, twice-fermented ungerminated chickpea tempeh, single-strain fermentation of germinated chickpea tempeh by Rhizopus oryzae, and commercially available chickpea tempeh, the free amino acid content, composition, and isoflavone monomer content of the chickpea tempeh prepared by the germination treatment and two fermentation treatments in the embodiments of the present application are all significantly improved, indicating that the germination treatment combined with two fermentation treatments can significantly improve the nutritional quality of chickpea tempeh, and Lactobacillus plantarum and Rhizopus oryzae show a synergistic effect. Compared with single-strain fermentation alone, the synergy between the two significantly improves the nutritional value of chickpea tempeh.

[0091] Table 4

[0092]

[0093]

[0094] Note: Different lowercase superscripts in the same row indicate significant differences (P < 0.05); "-" indicates not detected.

[0095] Table 5

[0096]

[0097] Note: Different lowercase superscripts in the same row indicate significant differences (P < 0.05); "-" indicates not detected.

[0098] Table 6

[0099]

[0100] Note: Different lowercase superscripts in the same row indicate significant differences (P < 0.05); "-" indicates not detected.

[0101] Industrial Applicability

[0102] Through the synergistic effect of germination, lactic acid bacteria fermentation, and Rhizopus oryzae fermentation, the present invention effectively improves the protein digestibility, antioxidant activity, and flavor of chickpeas, enhances the functionality and sensory quality of tempeh, and can be widely applied to the development of high-protein plant-based foods, functional fermented foods, and vegetarian products, with good market application prospects.

[0103] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0104] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for fermenting chickpeas, characterized in that, The method includes: Subjecting chickpeas to conditions suitable for germination to cause germination, obtaining germinated chickpeas; Subjecting the germinated chickpeas to a cooking process to obtain cooked chickpeas; Introducing one of Lactobacillus plantarum and Rhizopus oryzae into the cooked chickpeas to perform a first fermentation thereon, obtaining first-fermented chickpeas; and Introducing the other of Lactobacillus plantarum and Rhizopus oryzae into the first-fermented chickpeas to perform a second fermentation thereon, obtaining second-fermented chickpeas.

2. The method according to claim 1, wherein The method includes: Introducing Lactobacillus plantarum into the cooked chickpeas to perform the first fermentation thereon, obtaining the first-fermented chickpeas; and Introducing Rhizopus oryzae into the first-fermented chickpeas to perform the second fermentation thereon, obtaining the second-fermented chickpeas, Optionally, the method further includes: inactivating the Lactobacillus plantarum in the first fermentation before performing the second fermentation.

3. The method according to claim 2, wherein The conditions suitable for germination include: A germination temperature of 15 - 37 °C, preferably 20 - 30 °C, more preferably 25 °C; and A germination relative humidity of 50% - 90%, preferably 65% - 75%, more preferably 80%, wherein the chickpeas are subjected to the germination conditions for 6 - 96 h, preferably 12 - 72 h, more preferably 24 - 72 h to cause germination.

4. The method according to claim 3, characterized in that, The first fermentation specifically includes: Introduce 2%-10% (v / v), preferably 3%-5% (v / v) of Lactobacillus plantarum into the cooked chickpeas, wherein the concentration of the Lactobacillus plantarum is 10 4 -10 10 CFU / mL, preferably 10 6 -10 9 CFU / mL, more preferably 10 8 CFU / mL; and Fermenting the cooked chickpeas introduced with Lactobacillus plantarum under conditions suitable for the fermentation of Lactobacillus plantarum, Optionally, the conditions suitable for the fermentation of Lactobacillus plantarum include: fermenting at 20 - 40 °C, preferably 37 °C for 4 - 10 h, preferably 5 - 8 h, more preferably 6 h.

5. The method according to claim 4, characterized in that, The second fermentation specifically includes: Introducing 0.1% - 2% (w / w), preferably 0.2% (w / w) of Rhizopus oryzae into the first-fermented chickpeas; and Fermenting the first-fermented chickpeas introduced with Rhizopus oryzae under conditions suitable for the fermentation of Rhizopus oryzae, Optionally, the conditions suitable for the fermentation of Rhizopus oryzae include: fermenting at 20 - 40 °C, preferably 37 °C for 10 - 40 h, preferably 12 - 36 h, more preferably 24 - 32 h.

6. The method according to claim 5, wherein The cooking process includes: Boiling the germinated chickpeas in water and then peeling them to obtain peeled chickpeas; and Steaming the peeled chickpeas to obtain the cooked chickpeas.

7. The method according to any one of claims 1 to 6, characterized in that Before germination, the method further includes: Soaking the chickpeas in water for pre-germination treatment, Optionally, soaking the chickpeas in water at 20 - 25 °C for 8 - 12 h for pre-germination treatment, Optionally, before performing the pre-germination treatment on the chickpeas, the method further includes: washing the chickpeas.

8. A method for preparing chickpea tempeh, characterized in that, The method includes: fermenting chickpeas according to the method of any one of claims 1 to 7 to obtain second-fermented chickpeas as the tempeh of chickpeas.

9. A chickpea tempeh, characterized in that, The tempeh of chickpeas is prepared according to the method of claim 8.

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