Pickled eucheuma gelatinae obtained through multi-strain synergistic fermentation and preparation method of pickled eucheuma gelatinae

Abstract

The invention relates to the technical field of food technologies, in particular to multi-strain synergistic fermentation pickled eucheuma gelatinae and a preparation method thereof.The preparation method comprises the steps that eucheuma gelatinae is soaked in a mixed solution A to obtain a mixture B, and the mixed solution A comprises white granulated sugar, edible salt and water; mixed thalli are inoculated into the mixture B to obtain a mixture C, the mixture C is cultured and fermented to obtain the pickled eucheuma gelatinae, the mixed thalli comprise lactobacillus plantarum, leuconostoc mesenteroides and lactobacillus fermentum, the inoculation volume ratio of the lactobacillus plantarum to the leuconostoc mesenteroides to the lactobacillus fermentum in the mixed thalli is (1-3): (1-3): (1-3), and the inoculation volume ratio of the lactobacillus plantarum to the leuconostoc mesenteroides to the lactobacillus fermentum is (1-3): (1-3): (1-3). The eucheuma gelatinae pickle product obtained by the preparation method disclosed by the invention is crisp and tasty in taste, moderate in acidity, unique in flavor, short in fermentation time, high in phenolic substance content, relatively strong in antioxidant activity, low in nitrite content and low in harmful mineral substance content, and is a nutritional and safe seaweed pickle product.

Description

Technical Field

[0001] The present application relates to the field of food processing technology, and more specifically, to a multi-strain synergistically fermented Eucheuma agaricus kimchi and a preparation method thereof. Background Art

[0002] Eucheumagelatinae, also known as Eucheuma, belongs to the family Rhodophyceae, Rhodophyta, and is a large marine economic algae widely distributed in tropical and subtropical areas. Eucheuma has high edible and medicinal value, rich in polysaccharides, minerals, vitamins, polyphenols and other bioactive substances, and has good lipid-lowering, antiviral, anti-inflammatory and antioxidant effects. However, due to its strong fishy smell and rough algae, it is often used to extract active substances and animal feed processing.

[0003] Kimchi is one of the traditional fermented foods in China. It not only contains a large amount of vitamins and minerals, but its fermented products also have a variety of biological activities, such as anti-obesity, anti-oxidation, anti-cancer and cholesterol-lowering effects. Kimchi is made by pre-treating vegetables and then soaking them in a salt solution of a certain concentration. The vegetables are fermented by their own microorganisms (natural fermentation) or artificially inoculated with high-quality lactic acid bacteria (inoculation fermentation). Accompanied by alcohol fermentation and acetic acid fermentation, a fermented product with a unique flavor is formed.

[0004] In recent years, with the development of food industry, the development of Qiongzhi food has gradually attracted people's attention. However, the processing method of Qiongzhi is relatively single at present, and it is usually made into cold dishes, dried products, beverages, etc., but these products have the disadvantages of short shelf life, complex processing and poor flavor. The present invention ferments Qiongzhi by adopting a multi-strain cooperative fermentation method to obtain a kimchi product with good sensory characteristics, short fermentation cycle, low nitrite content and long shelf life. Summary of the invention

[0005] The purpose of the present invention is to provide a multi-strain cooperatively fermented Eucheuma japonicum pickled vegetable and a preparation method thereof, thereby providing a new method for processing Eucheuma japonicum products.

[0006] In a first aspect of the present application, a method for preparing multi-strain cooperatively fermented Eucheuma japonicum kimchi is provided, the preparation method comprising: soaking Eucheuma japonicum in a mixed solution A to obtain a mixture B, wherein the mixed solution A comprises sugar, salt and water;

[0007] The mixed bacteria are inoculated into the mixture B to obtain the mixture C, and the mixture C is cultured and fermented to obtain the Eucheuma kimchi. The mixed bacteria include Lactobacillus plantarum, Leuconostoc mesenteroides and Lactobacillus fermentum but are not limited to these three strains. The inoculation volume ratio of Lactobacillus plantarum, Leuconostoc mesenteroides and Lactobacillus fermentum in the mixed bacteria is 1-3:1-3:1-3.

[0008] Preferably, the volume ratio of Lactobacillus plantarum, Leuconostoc mesenteroides and Lactobacillus fermentum in the mixed bacteria is 2-3:2-3:1-2.

[0009] In some embodiments, the volume mass percentage of the mixed cells in the mixture B is 1%-9% (v / w), such as 1%, 3%, 5%, 7%, 9%, etc. Preferably, the volume mass percentage is 3%-7%.

[0010] In some embodiments, the fermentation time is 1 day to 9 days. Preferably, the fermentation time is 3 days to 7 days.

[0011] In some embodiments, the pH value of the mixture C during the fermentation process is 3.0-8.0.

[0012] In some embodiments, the percentage of sugar, salt and mixed solution A in the mixed solution A is 2%-10% (w / v), 1%-9% (w / v), respectively. Preferably, the percentage of sugar and mixed solution A in the mixed solution A is 4%-8% (w / v). Preferably, the mass volume percentage of salt and mixed solution A in the mixed solution A is 3%-7%.

[0013] In some embodiments, the mass ratio of the material to the liquid in the mixture B is 1:1-1:2.

[0014] In some embodiments, the fresh Eucheuma truncatum is pretreated before being soaked in mixture A, and the pretreatment process includes: washing, blanching, salting and dehydrating, washing, and draining the fresh Eucheuma truncatum in sequence.

[0015] Wash and soak the fresh Eucheuma truncatum to remove the mud and sand. Cut the fresh Eucheuma truncatum into pieces and blanch them in boiling water for 15s-30s, rinse with cold water and drain; after draining, salt and dehydrate them, add edible salt to the drained Eucheuma truncatum, and salt for 20h-30h. After dehydration, rinse and desalinate with clean water, wash 2 to 3 times, and drain until there is no water on the surface. The mass percentage of salt used for salting is 2%-6% (w / w) after draining the Eucheuma truncatum; preferably 3%-5% (w / w). Preferably, the salting time is 22h-28h.

[0016] In some embodiments, the seasoning includes one or more of ginger, garlic, chili and other seasonings. The seasoning is selected according to taste. In the present application, ginger, garlic and chili are added to mixture A. In some embodiments, the mass percentage of the total mass of ginger and garlic in mixture A in mixture B is 1%-5%, preferably 2%-3%. The mass percentage of chili in mixture B is 0.1%-5%, preferably 0.6%-2%.

[0017] A second aspect of the present application provides a kind of Eucheuma kimchi obtained by the preparation method of fermented Eucheuma kimchi described in any embodiment of the present application.

[0018] In some embodiments, the nitrite content of the Eucheuma japonicum kimchi is less than 4 mg / kg; and the Eucheuma japonicum kimchi contains phenolic substances.

[0019] In the fermented agar-chip kimchi product of the present invention, Lactobacillus plantarum, Leuconostoc mesenteroides and Lactobacillus fermentum are selected based on acid production ability, acid resistance ability, salt resistance ability and nitrite degradation ability. Fermentation strains with excellent characteristics are screened out from 6 commercial strains, which is conducive to the industrialized and standardized production of agar-chip kimchi.

[0020] Each embodiment of the present application provides a preparation method of multi-strain synergistically fermented Eucheuma truncatum kimchi, in which Eucheuma truncatum is fermented and cultured using mixed bacteria, wherein the inoculation volume ratio of Lactobacillus plantarum, Leuconostoc mesenteroides and Lactobacillus fermentum in the mixed bacteria is 1-3:1-3:1-3, and the fermentation system composed of the mixed bacteria and Eucheuma truncatum has a short overall fermentation time, and Eucheuma truncatum kimchi can be obtained within 5 days, which effectively improves the unpleasant flavor of Eucheuma truncatum and has the characteristics of crisp taste, moderate acidity and low nitrite content, and is a nutritious, safe and long-shelf-life kimchi product. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the drawings, which are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar parts. The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the specification and claims, are used to illustrate the embodiments applied for. When appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.

[0022] Figure 1 The effect of different salt addition amounts on the texture of Eucheuma japonica kimchi is shown (A corresponds to hardness, B corresponds to elasticity, and C corresponds to chewiness);

[0023] Figure 2 The effect of different amounts of added white sugar on the texture of Eucheuma japonica kimchi is shown (A corresponds to hardness, B corresponds to elasticity, and C corresponds to chewiness);

[0024] Figure 3 The effect of different lactic acid bacteria inoculation amounts on the texture of Eucheuma japonica kimchi is shown (A corresponds to hardness, B corresponds to elasticity, and C corresponds to chewiness);

[0025] Figure 4 The effect of different fermentation times on the texture of Eucheuma japonica kimchi is shown (A corresponds to hardness, B corresponds to elasticity, and C corresponds to chewiness);

[0026] Figure 5 The effects of different compounding ratios on the texture of Eucheuma japonica kimchi are shown (A corresponds to hardness, B corresponds to elasticity, and C corresponds to chewiness);

[0027] Figure 6 The top view and difference spectra of Qiongzhi Qilincai kimchi with different fermentation methods are shown (A corresponds to the top view, B corresponds to the difference spectrum);

[0028] Figure 7 The effects of different fermentation methods on the total phenolic and flavonoid contents of Agarwood kimchi are shown (A corresponds to the total phenolic content, B corresponds to the total flavonoid content);

[0029] Figure 8 The effects of different fermentation methods on the DPPH free radical scavenging activity of Eucheuma japonica kimchi were shown;

[0030] Fig. 9 The results show that different fermentation methods have an effect on the ABTS of Eucheuma japonicum kimchi. + Effects of free radical scavenging activity;

[0031] Fig.10 The results show that different fermentation methods have an effect on the Fe content of Eucheuma japonica kimchi. 3+ The impact of reducing capacity; DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific implementation examples. The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific implementation examples, but are not intended to limit the present application.

[0033] The words "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0034] The experimental methods involved in each embodiment of this application are as follows:

[0035] 1. Determination of pH, total number of lactic acid bacteria and nitrite content

[0036] At room temperature, place the pH electrode of the pH meter directly into the fermentation liquid to measure the pH value. Refer to GB 4789.35-2016 for lactic acid bacteria count. Refer to GB / T 5009.33-2016 for nitrite content.

[0037] 2. Determination of texture

[0038] TPA test was carried out using a texture analyzer. The measurement conditions used a P5 flat-bottom cylindrical probe, a trigger force of 5N, a speed of 1mm / s before measurement, a speed of 0.5mm / s during measurement, and a speed of 1mm / s after measurement. The sample compression deformation was 85%, and there was a pause of 3s between two compressions. Ten samples were randomly selected for testing and the average value was taken.

[0039] 3. Sensory evaluation

[0040] Standard scoring was made in reference to the national standards GB / T 10220-1988 and GB / T16291.1-2012 General Introduction to Sensory Analysis Methods. Ten graduate students majoring in food were organized to serve as evaluators to score the food in five aspects: color, smell, taste, texture and overall acceptability. The average score was taken, with a full score of 100.

[0041] Table 1 Sensory scoring standards

[0042] project feature score The surface is purple or red, uniform and has good glossiness 18～20 The surface is purple or red, more uniform and has better glossiness 15～17 Color (20 points) The surface is light red, more uniform, and the glossiness is duller 12～14 The surface is not red, uneven, and has poor glossiness 9～11 The color is messy and dull, with different colors <8 It has a strong fermentation-specific aroma and rich aroma 18～20 Has a fermented aroma and a soft fragrance 15～17 Smell (20 points) Has a fermented aroma, and the aroma is not soft enough 12～14 The fermented aroma is not obvious and has a slight fishy smell 9～11 No fermented aroma, strong fishy smell, or irritating odor <8 Salty and sour taste 18～20 Slightly salty or sour taste 15～17 Taste (20 points) Tastes too salty or sour 12～14 The taste is not obvious or accurate, and there is a strange smell 9～11 Strong odor and obvious discomfort <8 Moderate hardness, crispy taste, good elasticity 18～20 Moderate hardness, crispy texture, good elasticity 15～17 Texture (20 points) Slightly hard or soft, average taste, average elasticity 12～14 Too hard or too soft, poor taste, poor elasticity 9～11 Rough texture, no crispness, no elasticity <8 Like it very much 18～20 like 15～17 Overall acceptability (20 points) Slightly like 12～14 dislike 9～11 Very dislike <8

[0043] 4. Determination of volatile flavor substances

[0044] Table 2 Analysis conditions

[0045]

[0046]

[0047] Table 3 Gas chromatography conditions

[0048] Time E1 E2 R 00:00,000 150mL / min 2mL / min rec 02:00,000 150mL / min 2mL / min - 10:00,000 150mL / min 10mL / min - 20:00,000 150mL / min 100mL / min - 30:00,000 150mL / min 150mL / min - 35:00,000 150mL / min 150mL / min stop

[0049] 5. Determination of organic acids

[0050] Refer to national standard GB / T 5009.157-2016.

[0051] 6. Determination of mineral content

[0052] With reference to GB 5009.268-2016, microwave digestion-inductively coupled plasma mass spectrometry was used.

[0053] 7. Extraction of active substances

[0054] The freeze-dried powder of Qiongzhi kimchi was mixed with 90% methanol solution at a liquid-to-solid ratio of 1:20, and the mixture was stirred and extracted for 24 hours at 25°C and 500r / min using a magnetic stirrer. The extract was centrifuged at 4°C and 4000r / min for 10 minutes, the supernatant was collected, and the extraction was repeated twice. The collected supernatants were combined, concentrated using a rotary evaporator, and dissolved in DMSO to obtain an extract.

[0055] 8. Determination of total phenol content

[0056] The total phenol content of the extract of Agarwood kimchi was determined using the Folin phenol colorimetric method. After the extract was appropriately diluted, 10 μL was added to a 96-well plate, and 10 μL of Folin phenol reagent was reacted for 6 minutes. Then 100 μL of sodium carbonate solution and 80 μL of deionized water were added in sequence, and the 96-well plate was gently shaken. After incubation in the dark for 90 minutes, the absorbance was measured at 760 nm.

[0057] 9. Determination of total flavonoids content

[0058] At room temperature, 9 μL NaNO2 solution (5% m / v), 150 μL pure water and 30 μL sample solution were mixed in a 96-well plate for 6 min, and then 18 μL AlCl3·6H2O solution (10% m / v) was added for 5 min. Finally, 60 μL NaOH solution (1 mol / L) was added and the absorbance was measured at 510 nm.

[0059] 10. Determination of DPPH free radical scavenging activity

[0060] Take 100 μL of sample and 100 μL of DPPH solution (6×10 5 mmol / L) were mixed and kept at room temperature in the dark for 30 min, and the absorbance was measured at 517 nm. 100 μL sample plus 100 μL DPPH reagent was A1, 100 μL sample plus 100 uL anhydrous ethanol was A2, and 100 uL deionized water plus 100 μL DPPH reagent was A3.

[0061] The clearance rate was calculated as

[0062] 11. Fe 3+ Reducing power (FRAP), ABTS + Determination of free radical scavenging activity

[0063] The assay was performed using a commercial kit according to the instructions.

[0064] Lactobacillus plantarum (ACCC 11095) and Leuconostoc mesenteroides (CICC 21861) were purchased from Beijing Baozang Biotechnology Co., Ltd.; Lactobacillus fermentum (BNCC 194173) was purchased from Henan Microbial Culture Collection Center.

[0065] Example 1

[0066] The present embodiment provides a fermented Eucheuma japonicum pickled vegetable product, and the preparation method thereof comprises the following steps:

[0067] (1) Raw material pretreatment: fresh Eucheuma chinensis was cleaned, soaked in clean water overnight to remove mud and sand, cut into pieces, blanched in boiling water for 15s-30s, immediately cooled in cold water, drained, added with 4% (w / w) edible salt, salted for 24h, washed with clean water 2-3 times, and then drained until there was no water on the surface;

[0068] (2) Preparation of sugar and salt water: Add 6% (w / v) white sugar and 5% (w / v) edible salt to distilled water, boil for 60 seconds, and cool at room temperature to prepare sugar and salt water (mixed solution A);

[0069] (3) soaking the Eucheuma obtained in step (1) in the sugar-salt water prepared in step (2), adding 3% (w / w) ginger and garlic, and 1% (w / w) chili pepper, with a material-liquid ratio of 1:1.5;

[0070] (4) Inoculation: The three lactic acid bacteria were cultured at 37° C. for 10 h to 14 h respectively. After the strains were in the logarithmic growth phase, they were activated for 2 to 3 generations. The culture solution was transferred to a sterilized 50 mL centrifuge tube and centrifuged (4° C., 6000 r / min, 5 min). The supernatant was discarded, and the bacteria were rinsed twice with 0.85% (w / v) sterile saline and suspended in 0.85% (w / v) saline to prepare a bacterial suspension. The volume ratio of Lactobacillus plantarum, Leuconostoc mesenteroides and Lactobacillus fermentum was 3:2:1, and the total inoculation amount was 3% (v / w);

[0071] (5) Fermentation: Ferment in a constant temperature incubator at 37°C for 5 days. When the pH value is less than 3.3 and tends to be stable, the fermented Qiongzhi Qilincai kimchi product is obtained.

[0072] Example 2

[0073] The effects of different salt addition amounts on the total lactic acid bacteria count, pH value, nitrite content, sensory score and texture of the fermented Eucheuma truncatum kimchi product were investigated. The Eucheuma truncatum kimchi product was prepared according to a method similar to Example 1, except that the salt addition amounts in step (2) were 1, 3, 7 and 9%, respectively. The index measurement results of Eucheuma truncatum kimchi with different salt addition amounts are shown in Table 4.

[0074] Table 4 Effects of different salt addition amounts on the total lactic acid bacteria count, pH value, nitrite content and sensory scores of Eucheuma kimchi

[0075] Salt Addition 1％ 3％ 5％ 7％ 9％ Total lactic acid bacteria count (lgCFU / mL) <![CDATA[7.75±0.11 c ]]> <![CDATA[8.18±0.08 a ]]> <![CDATA[8.30±0.06 a ]]> <![CDATA[7.96±0.08 b ]]> <![CDATA[6.25±0.10 d ]]> pH <![CDATA[3.18±0.02 c ]]> <![CDATA[3.19±0.02 c ]]> <![CDATA[3.23±0.02 c ]]> <![CDATA[3.42±0.03 b ]]> <![CDATA[3.53±0.04 a ]]> Nitrite content (mg / kg) <![CDATA[3.09±0.10 b ]]> <![CDATA[1.97±0.16 c ]]> <![CDATA[1.62±0.06 d ]]> <![CDATA[2.96±0.04 b ]]> <![CDATA[3.37±0.08 a ]]> Sensory Rating <![CDATA[78.60±2.24 c ]]> <![CDATA[81.80±2.71 b ]]> <![CDATA[86.00±3.35 a ]]> <![CDATA[83.50±2.91 ab ]]> <![CDATA[77.40±2.29 c ]]>

[0076] It can be seen from Table 4 that when a certain amount of salt is added, the lactic acid bacteria grow and reproduce better, the nitrite content is lower, the sensory score is higher, the taste is sweet and sour, and the aroma is soft. When the salt concentration is too high, the growth of lactic acid bacteria will be inhibited, the nitrite content will increase, the sensory score will decrease, the organic acid content will be lower, the sensory organs will be poor, and the taste will be salty.

[0077] from Figure 1 It can be seen from (A, B, C) that the hardness, elasticity and chewiness of the kimchi treated with high salt concentration are higher than those of the kimchi treated with low salt concentration. This shows that when the concentration of added edible salt is too high, the growth and reproduction of lactic acid bacteria is inhibited, the acid production capacity decreases, and the texture characteristics of the kimchi are not improved, resulting in the kimchi having higher hardness, elasticity and chewiness, and poor taste and edibility. Finally, the salt addition amount was determined to be 5%.

[0078] Example 3

[0079] The effects of different amounts of added white sugar on the total lactic acid bacteria count, pH value, nitrite content, sensory score and texture of the fermented Euphorbia cerana pickle product were investigated. The Euphorbia cerana pickle product was prepared according to a method basically the same as that in Example 1, except that the amounts of added white sugar in step (2) were 2, 4, 8 and 10%, respectively. The index measurement results of Euphorbia cerana pickles with different amounts of added white sugar are shown in Table 5.

[0080] Table 5 Effects of different amounts of white sugar added on the total number of lactic acid bacteria, pH value, nitrite content and sensory scores of Eucheuma kimchi

[0081] Added amount of white sugar 2％ 4％ 6％ 8％ 10％ Total lactic acid bacteria count (lgCFU / mL) <![CDATA[7.66±0.06 c ]]> <![CDATA[8.08±0.08 b ]]> <![CDATA[8.31±0.05 a ]]> <![CDATA[7.41±0.03 d ]]> <![CDATA[7.19±0.03 e ]]> pH <![CDATA[3.30±0.01 a ]]> <![CDATA[3.27±0.02 ab ]]> <![CDATA[3.23±0.02 c ]]> <![CDATA[3.26±0.02 bc ]]> <![CDATA[3.30±0.01 a ]]> Nitrite content (mg / kg) <![CDATA[3.39±0.17 a ]]> <![CDATA[3.13±0.09 b ]]> <![CDATA[1.67±0.05 e ]]> <![CDATA[2.20±0.07 d ]]> <![CDATA[2.78±0.10 c ]]> Sensory Rating <![CDATA[73.50±3.53 c ]]> <![CDATA[79.90±2.62 b ]]> <![CDATA[85.00±1.73 a ]]> <![CDATA[83.30±2.53 a ]]> <![CDATA[75.60±3.14 c ]]>

[0082] As can be seen from Table 5, white sugar can provide sufficient energy for lactic acid bacteria fermentation, promote the reproduction of lactic acid bacteria, and accelerate the growth rate. Adding an appropriate amount of white sugar can effectively improve the sensory perception of the product, reduce the irritation of the sour taste, maintain the unique flavor of the Qiongzhi Eucheuma, and improve the overall acceptability of the product.

[0083] from Figure 2 It can be seen from (A, B, C) that the hardness, elasticity and chewiness of Qiongzhi kimchi show a trend of decreasing and then increasing with the increase of the amount of white sugar added. The hardness and chewiness show a downward trend when the sugar content is 2% to 8%, and then increase again when the addition amount is 10%; the elasticity shows a downward trend when the sugar content is 2% to 6%, and there is no significant change with the increase of the amount of white sugar. Finally, the amount of white sugar added was determined to be 6%.

[0084] Example 4

[0085] The effects of different lactic acid bacteria inoculation amounts on the total lactic acid bacteria count, pH value, nitrite content, sensory score and texture of the fermented Eucheuma kimchi product were investigated. The Eucheuma kimchi product was prepared according to a method basically the same as that in Example 1, except that the lactic acid bacteria inoculation amounts in step (4) were 1, 5, 7 and 9%, respectively. The index determination results of Eucheuma kimchi with different lactic acid bacteria inoculation amounts are shown in Table 6.

[0086] Table 6 Effects of different lactic acid bacteria inoculation amounts on the total lactic acid bacteria count, pH value, nitrite content and sensory scores of Eucheuma kimchi

[0087] Lactic acid bacteria inoculation amount 1％ 3％ 5％ 7％ 9％ Total lactic acid bacteria count (lgCFU / mL) <![CDATA[7.79±0.08 d ]]> <![CDATA[8.16±0.03 b ]]> <![CDATA[8.28±0.02 a ]]> <![CDATA[8.07±0.03 bc ]]> <![CDATA[7.98±0.05 c ]]> pH <![CDATA[3.43±0.03 a ]]> <![CDATA[3.22±0.02 b ]]> <![CDATA[3.21±0.02 b ]]> <![CDATA[3.23±0.02 b ]]> <![CDATA[3.22±0.03 b ]]> Nitrite content (mg / kg) <![CDATA[2.08±0.06 b ]]> <![CDATA[1.54±0.09 d ]]> <![CDATA[1.26±0.02 e ]]> <![CDATA[1.79±0.11 c ]]> <![CDATA[2.49±0.15 a ]]> Sensory Rating <![CDATA[74.50±3.07 d ]]> <![CDATA[82.60±1.80 b ]]> <![CDATA[85.70±1.42 a ]]> <![CDATA[79.80±2.23 c ]]> <![CDATA[72.80±2.27 d ]]>

[0088] As can be seen from Table 6, with the increase of lactic acid bacteria inoculation amount, the nitrite content shows a trend of first decreasing and then increasing, and the product quality first increases and then decreases. When the inoculation amount is low, kimchi ferments slowly, the growth cycle of lactic acid bacteria is prolonged and affected by miscellaneous bacteria, the acid production ability is weak, and the taste and aroma are poor; when the appropriate amount of lactic acid bacteria is inoculated, the aroma is strong and the taste is good; when the inoculation amount is too high, the acid production is fast in the early stage of fermentation, the number of lactic acid bacteria in the fermentation system is too large and the available carbon source is limited, resulting in an increase in the number of lactic acid bacteria deaths, a strong sour taste of the product, and an unharmonious flavor.

[0089] like Figure 3 It can be seen from (A, B, C) that when the inoculation amount is small, some spoilage bacteria will grow slowly due to the slow growth of the bacteria, which often has an adverse effect on the texture of the fermented product; when the lactic acid bacteria inoculation amount is large, the growth rate is fast in the early stage, and the nutrients are consumed in the later stage, the product is not fully fermented, and the texture does not change significantly. Therefore, the lactic acid bacteria inoculation amount is determined to be 5%.

[0090] Example 5

[0091] The effects of different fermentation times on the total lactic acid bacteria count, pH value, nitrite content, sensory score and texture of the fermented Euphorbia cerevisiae kimchi product were investigated. The Euphorbia cerevisiae kimchi product was prepared according to a method basically the same as that in Example 1, except that the fermentation times in step (5) were 1, 3, 7 and 9 days, respectively. The index measurement results of Euphorbia cerevisiae kimchi with different fermentation times are shown in Table 7.

[0092] Table 7 Effects of different fermentation times on the total lactic acid bacteria count, pH value, nitrite content and sensory scores of Eucheuma kimchi

[0093] Fermentation time 1d 3d 5d 7d 9d Total lactic acid bacteria count (lgCFU / mL) <![CDATA[7.85±0.03 c ]]> <![CDATA[8.41±0.03 a ]]> <![CDATA[8.18±0.03 b ]]> <![CDATA[6.88±0.08 d ]]> <![CDATA[6.19±0.02 e ]]> pH <![CDATA[3.38±0.02 a ]]> <![CDATA[3.33±0.02 a ]]> <![CDATA[3.21±0.03 b ]]> <![CDATA[3.21±0.01 b ]]> <![CDATA[3.24±0.02 b ]]> Nitrite content (mg / kg) <![CDATA[3.06±0.07 a ]]> <![CDATA[1.94±0.11 b ]]> <![CDATA[1.42±0.09 c ]]> <![CDATA[1.26±0.11 cd ]]> <![CDATA[1.18±0.08 d ]]> Sensory Rating <![CDATA[72.30±2.61 d ]]> <![CDATA[77.80±3.74 bc ]]> <![CDATA[84.60±1.56 a ]]> <![CDATA[81.60±1.80 b ]]> <![CDATA[73.50±2.80 cd ]]>

[0094] As can be seen from Table 7, with the extension of fermentation time, the total number of lactic acid bacteria first increased and then decreased, the pH value tended to be stable, the nitrite content gradually decreased and tended to be stable, and the sensory score on the 5th day was higher. Since lactic acid bacteria grow slowly in the early stage of fermentation, lactic acid bacteria have not yet become the dominant flora; in the middle stage of fermentation, with the accumulation of lactic acid, the environmental conditions are suitable for the growth and reproduction of lactic acid bacteria, the number of bacteria increases significantly, and the acid production is faster. When the number of lactic acid bacteria tends to be stable, it decreases rapidly as the fermentation proceeds, indicating that the proliferation of lactic acid bacteria is strongly inhibited in the late stage of fermentation.

[0095] like Figure 4 As can be seen from (A, B, C), the hardness, elasticity and chewiness of the agarwood kimchi have roughly the same changing trend, and all of them significantly decrease with the extension of fermentation time. This may be because the lactic acid bacteria effectively utilize the macromolecular substances in the agarwood, causing the kimchi to become soft, and the elasticity and chewiness also decrease accordingly, thereby increasing its edibility. Finally, the fermentation time was determined to be 5 days.

[0096] Example 6

[0097] The effects of different compounding ratios on the total lactic acid bacteria count, pH value, nitrite content and sensory evaluation of the fermented Eucheuma truncatum kimchi product were investigated. The Eucheuma truncatum kimchi product was prepared according to a method basically the same as that in Example 1, except that the volume ratios of Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides were different, and the inoculation ratios in step (4) were 1:0:0, 0:1:0, 0:0:1, 1:1:0, 1:0:1, 0:1:1, 1:1:1, 1:2:3, 1:3:2, 2:1:3, 2:3:1 and 3:1:2, respectively. The index determination results of Eucheuma truncatum kimchi with different compounding ratios are shown in Table 8.

[0098] Table 8 Effects of different compound ratios on the total lactic acid bacteria count, pH value, nitrite content and sensory score of Eucheuma kimchi

[0099]

[0100] From Table 8, it can be seen that the three-strain compound fermentation is better than the single-strain and double-strain fermentation. This may be due to the complementary and synergistic effects between multiple strains. Different lactic acid bacteria have unique growth and metabolic characteristics, can adapt to different conditions and environments, produce more metabolites and active substances, optimize fermentation conditions, improve fermentation efficiency, and improve the quality of fermented foods. Among them, the pH value and nitrite content of the 3:2:1 compound ratio are the lowest, with a pH value as low as 3.20 and a nitrite content as low as 1.57 mg / kg. The total number of lactic acid bacteria in 2:3:1 and 3:2:1 is the highest, 8.30 lg CFU / mL and 8.36 lg CFU / mL, respectively. Through comprehensive comparison, the combination of Lactobacillus plantarum: Leuconostoc mesenteroides: Lactobacillus fermentum = 3:2:1 is more conducive to the fermentation of Qiongzhi kimchi and can be used as the optimal strain ratio.

[0101] The texture evaluation results of agarwood pickles fermented with different ratios of lactic acid bacteria are as follows Figure 5 (A, B, C). Combining the results of texture and sensory scores, the three-strain compound fermentation was better than the single-strain and double-strain fermentation, and the optimal compound ratio was finally determined to be 3:2:1.

[0102] Example 7

[0103] This embodiment provides a kimchi product of Eucheuma japonicum after optimizing fermentation conditions, and the preparation method thereof comprises the following steps:

[0104] (1) Raw material pretreatment: The fresh Eucheuma chinensis was cleaned, soaked in clean water overnight to remove mud and sand, cut into pieces, blanched in boiling water for 30 seconds, rinsed with cold water, drained, and salted for dehydration. 4% (w / w) edible salt was added for salting for 24 hours, rinsed with clean water for desalination, washed 2 to 3 times, and then drained until there was no water on the surface;

[0105] (2) Preparation of sugar and salt water: Add 5.2% (w / v) white sugar and 4.7% (w / v) edible salt to clean water, boil the mixture, and cool the mixture to room temperature to prepare a sugar and salt water solution (mixed solution A);

[0106] (3) soaking the Eucheuma obtained in step (1) in the sugar-salt water prepared in step (2), and adding 3% (w / w) ginger and garlic and 1% (w / w) chili pepper, with a material-liquid ratio of 1:1.5;

[0107] (4) Inoculation: The three lactic acid bacteria were cultured at 37° C. for 10 h to 14 h to reach the logarithmic growth phase of the strains, and then activated for 2 to 3 generations. The culture solution was transferred to a sterilized 50 mL centrifuge tube and centrifuged (4° C., 6000 r / min, 5 min). After centrifugation, the supernatant was discarded, and the bacteria were rinsed twice with 0.85% (w / v) sterile saline and suspended in 0.85% (w / v) saline to prepare a bacterial suspension. The volume ratio of Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides was 3:2:1, and the total inoculation amount was 4.2% (v / w);

[0108] (5) Fermentation: Fermenting in a constant temperature incubator at 37° C. for 5 days. When the pH value is less than 3.3 and tends to be stable, the fermented Qiongzhi Qilincai kimchi product is obtained.

[0109] Example 8

[0110] The effects of different fermentation methods on the organic acids of pickled cabbage during the fermentation process were investigated. The natural fermentation method was different from that in Example 7 in that the inoculation process in step (4) was omitted. The inoculation fermentation method was the same as that in Example 7 in each step. The results are shown in Table 9.

[0111] Table 9 Effects of different fermentation methods on organic acids in agarwood during fermentation

[0112]

[0113]

[0114] The present application compares the changes in the contents of seven kinds of organic acids in pickled mustard greens during the fermentation process of two fermentation methods, including tartaric acid, malic acid, lactic acid, citric acid, succinic acid, acetic acid and fumaric acid, which are usually present in fermented pickled mustard greens. As shown in Table 9, the types of organic acids in pickled mustard greens fermented by the two fermentation methods are consistent, mainly malic acid, succinic acid, tartaric acid, acetic acid and lactic acid, but there are differences in content. Fumaric acid and citric acid were not detected in the fermentation process of the two kinds of pickled mustard greens. This may be because citric acid is converted to produce succinic acid and acetic acid in the tricarboxylic acid cycle. The content of lactic acid in fermented pickled mustard greens is higher than that of tartaric acid, malic acid, acetic acid and succinic acid, which shows that pickled mustard greens fermentation mainly produces lactic acid. Lactic acid, as the main organic acid in pickled mustard greens, imparts a softer taste, replaces bitterness and astringency, and improves the microbial stability of the fermented product.

[0115] Example 9

[0116] The differences in volatile organic compounds of pickled mustard greens obtained by different fermentation methods were investigated. The natural fermentation method differed from Example 7 in that the inoculation process in step (4) was omitted. The inoculation fermentation method was the same as that in Example 7 in each step. Figure 6As can be seen from (A, B), most signals appear at retention times of 100s-1100s and drift times of 4.0-8.0. There are differences in the types and concentrations of volatile components of the two types of kimchi. Taking the naturally fermented Qiongzhi kimchi sample as the control, the red area of ​​the inoculated fermentation group becomes larger and the color becomes darker, indicating that compared with the naturally fermented samples, inoculated fermentation can increase the content of volatile compounds to varying degrees and improve the flavor. The content of some volatile components increases due to the addition of lactic acid bacteria for fermentation, while others decrease. Among them, the inoculated fermentation samples have significant differences, which indicates that lactic acid bacteria have different degrees of influence on different volatile components of Qiongzhi kimchi, and when multiple lactic acid bacteria are added, the content of flavor components formed is higher. It is the dynamic changes of these volatile components that form the flavor characteristics of Qiongzhi Qilincai kimchi.

[0117] Furthermore, the volatile organic compounds in the samples were qualitatively analyzed by matching the GC-IMS database. The qualitative analysis results of the volatile substances in different kimchi samples are shown in Table 10, and the quantitative analysis results of the volatile substances in different kimchi samples are shown in Table 11.

[0118] Table 10 Qualitative analysis of volatile substances in different kimchi samples

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126] Table 11 Quantitative analysis of volatile substances in different kimchi samples

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135] As can be seen from Tables 10 and 11, a total of 140 volatile components were detected, including 26 aldehydes, 22 ketones, 20 alcohols, 15 esters, 15 hydrocarbons, 4 sulfides, 2 acids, 3 pyrazines, 2 pyridines, 1 furan, 1 ether, 1 amine, and 28 unidentified compounds. Among them, 19 single volatile compounds, such as acetic acid, nonanal, n-hexanol, (E)-2-heptenal, and 1-pentanol, may produce multiple spots or signals, which are interpreted as monomers and dimers at different levels in the fingerprint area.

[0136] In the test results of the present application, aldehydes are the first type of volatile flavor substances in Qiongzhi kimchi detected based on GC-IMS, with a total of 26 species. Among them, 2-hexenal, acrolein and propionaldehyde D are the key aldehydes in fermented Qiongzhi kimchi. After inoculation and fermentation, (E)-2-hexenal, which is described as having a fruity and green aroma, showed a significant increase in signal intensity, while the signal intensity of nonanal and 3-methylthiopropionaldehyde decreased. These data indicate that inoculation and fermentation help remove odors in Qiongzhi Qiongzhi kimchi products.

[0137] Ketones are the second type of volatile flavor substances in pickled cabbage based on GC-IMS detection, with a total of 22 species. Ketones are produced by the oxidation or degradation of unsaturated fatty acids and amino acids. The presence of ketones is beneficial to the sensory attributes of sauerkraut, which is associated with floral, fruity and creamy flavors. In the test results of the present application, acetoxy-2-propanone, 4-methyl-2-pentanone, acetone and 3-hydroxy-2-butanone D are the key ketones in fermented pickled cabbage. In the inoculated fermented pickled cabbage, the signal intensity of 2-pentanone, which has a sweet fruity and woody aroma, increased significantly.

[0138] Alcohol volatile substances mainly provide unique sweetness, floral and rose aroma. In the test results of this application, the changes in alcohol volatiles and the accumulation of odors are mainly caused by three biochemical pathways: ethanol fermentation metabolism, amino acid catabolism, and fatty acid catabolism. Among them, 2-ethyl-1-hexanol, n-hexanol M, ethanol D, and methyl phenyl carbinol are the key alcohols in fermented agarwood pickles, mainly providing floral, wine, green and aromatic odors. Among them, ethanol is the most abundant alcohol compound produced in agarwood pickles.

[0139] In addition, other volatile substances such as esters, acids, sulfides and pyrazines were detected. Esters produce fruity and sweet flavors in fermented products. Inoculation fermentation reduced the sulfide and pungent smell of garlic and onion, increased the sweet, flower, sour, spice and fat aroma of the overall flavor, and further enriched the flavor of Qiongzhi Qilincai kimchi.

[0140] Example 10

[0141] The effects of different fermentation methods on the mineral content of pickled mustard greens were investigated. The natural fermentation method differed from Example 7 in that the inoculation process in step (4) was omitted. The inoculation fermentation method was the same as that in Example 7 in terms of each step. The results are shown in Table 12.

[0142] Table 12 Effects of different fermentation methods on the mineral content of Qiongzhi kimchi

[0143]

[0144] It can be obtained by Table 12 that the food safety of Chinese kimchi is improved by fermentation. Compared with unfermented Chinese kimchi, the Chinese kimchi obtained by inoculation and fermentation reduces the content of harmful trace metals. Elements such as Zn, Mn, and Fe are essential mineral trace elements for human body and plant growth. Although the content in human body is very small, they participate in the normal metabolism and growth and development of the body, and play an important role in the normal life activities of human body. When they are lacking or too much, they will cause the imbalance of human physiological function and even cause disease. Data from Table 12 show that the trace elements of zinc, manganese and iron are rich in Chinese kimchi. In addition, the fermented Chinese kimchi also contains abundant potassium and magnesium elements. According to the relevant provisions of GB19643-2016 "National Food Safety Standard for Limits of Contaminants in Algae and Their Products", GB 2762-2017 "National Food Safety Standard for Limits of Contaminants in Food", and "Green Industry Standard for Foreign Trade of Medicinal Plants and Preparations", lead (Pb) ≤ 1.0 mg / kg DW, cadmium (Cd) ≤ 0.3 mg / kg DW, copper (Cu) ≤ 20 mg / kg DW, arsenic (As) ≤ 2.0 mg / kg DW, the contents of harmful elements such as lead, arsenic, and cadmium in the inoculated and fermented Qiongzhi kimchi meet the standards.

[0145] Embodiment 11

[0146] The effects of different fermentation methods on the content of active ingredients in Qiongzhi kimchi were investigated, wherein the natural fermentation method differs from Example 7 in that the inoculation process of step (4) is omitted, and the inoculation fermentation method is the same as the various steps of Example 7. Among phytochemicals, plant polyphenols are considered to be effective antioxidants because they have high redox potentials, which enables them to act as reducing agents, hydrogen donors, singlet oxygen quenchers, and metal chelators. Qiongzhi kimchi is rich in phenolic compounds, flavonoids, and other compounds, which may be the main reason for its biologically active properties. This application explores the content of phenolic substances in Qiongzhi kimchi. The results are as follows Figure 8As shown in the figure, with the extension of fermentation time, the content of total phenols and total flavonoids showed an upward to stable trend, among which the content of total phenols and total flavonoids in inoculated fermented Qiongzhi kimchi was significantly higher than that in natural fermentation. This may be because the growth and reproduction of various dominant lactic acid bacteria in inoculated fermentation can produce more metabolites, which can promote the synthesis and conversion of phenolic compounds. The content of total flavonoids in Qiongzhi kimchi is higher than that of total phenols, which may be because during the fermentation process, lactic acid bacteria can use polysaccharides in the matrix to produce enzymes such as glucosidase, amylase, cellulase, chitinase and phytase, which can hydrolyze the ester bonds between polyphenols and polysaccharides, making it easier to release flavonoids.

[0147] Example 12

[0148] The effects of different fermentation methods on the antioxidant activity of Eucheuma japonicum were investigated. The natural fermentation method was different from that in Example 7 in that the inoculation process in step (4) was omitted. The inoculation fermentation method was the same as the steps in Example 7. Eucheuma japonicum kimchi products obtained by each fermentation method were freeze-dried and then the active substances were extracted. The antioxidant activity was then determined, including DPPH free radical scavenging activity, ABTS + Free radical scavenging activity, Fe 3+ Determination of reducing capacity. The results of the determination of the indicators of Eucheuma japonicum kimchi fermented by different fermentation methods are as follows: Figure 8 to Figure 10 As shown. Figure 8 to Figure 10 It can be found that the two fermentation methods of Eucheuma kimchi have scavenging effects on DPPH free radicals and ABTS + Free radical scavenging and Fe 3+ The reducing capacity showed an increasing trend with the increase of fermentation time, indicating that the antioxidant capacity of Qiongzhi kimchi gradually increased. In general, the antioxidant activity of Qiongzhi kimchi fermented by inoculation was higher than that of natural fermentation. This may be because lactic acid bacteria can degrade plant cell wall components and convert complex organic compounds in cells into small molecules with antioxidant properties. Lactic acid bacteria fermentation can convert phenolic compounds with low antioxidant capacity into phenolic compounds with high antioxidant capacity.

[0149] In addition, although exemplary embodiments have been described herein, the scope includes any and all embodiments based on the present application with equivalent elements, modifications, omissions, combinations (e.g., various embodiments intersecting schemes), adaptations or changes. The elements in the claims will be interpreted broadly based on the language adopted in the claims, and are not limited to the examples described in this specification or during the implementation of the application, and the examples will be interpreted as non-exclusive. Therefore, this specification and examples are intended to be considered as examples only, and the true scope and spirit are indicated by the following claims and the full scope of their equivalents.

[0150] The above description is intended to be illustrative rather than restrictive. For example, the above examples (or one or more of them) can be used in combination with each other. For example, those of ordinary skill in the art can use other embodiments when reading the above description. In addition, in the above-mentioned specific embodiments, various features can be grouped together to simplify the application. This should not be interpreted as a feature of an application that does not require protection being necessary for any claim. On the contrary, the subject matter of the present application may be less than all the features of the embodiments of a specific application. Thus, the following claims are incorporated into the specific embodiments as examples or embodiments, wherein each claim is independently used as a separate embodiment, and it is considered that these embodiments can be combined with each other in various combinations or arrangements. The scope of the present invention should be determined with reference to the full scope of the equivalent forms of the attached claims and these claims.

[0151] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A method for preparing Eucheuma agarwood kimchi by multi-strain cooperative fermentation, characterized in that: The preparation method comprises: The Eucheuma chinensis is soaked in a mixture A to obtain a mixture B, wherein the mixture A comprises sugar, salt and water; The mixed bacteria are inoculated into the mixture B to obtain the mixture C, and the mixture C is cultured and fermented to obtain the Eucheuma kimchi. The mixed bacteria include Lactobacillus plantarum, Leuconostoc mesenteroides and Lactobacillus fermentation. The inoculation volume ratio of Lactobacillus plantarum, Leuconostoc mesenteroides and Lactobacillus fermentation in the mixed bacteria is 1-3:1-3:1-3.

2. The preparation method according to claim 1, characterized in that: The volume ratio of Lactobacillus plantarum, Leuconostoc mesenteroides and Lactobacillus fermentum in the mixed bacteria is 2-3:2-3:1-2.

3. The preparation method according to claim 1, characterized in that: The percentage of the mixed bacteria in the mixture B is 1%-9% (v / w).

4. The preparation method according to claim 1, characterized in that: The time during the culture and fermentation process is 1d-9d.

5. The preparation method according to claim 1, characterized in that: The pH of the mixture C during the fermentation process is 3-8.

6. The preparation method according to claim 1, characterized in that: The percentage of sugar in the mixed solution A to the mixed solution A is 2%-10% (w / v).

7. The preparation method according to claim 1, characterized in that: The percentage of edible salt to mixed solution A is 1%-9% (w / v).

8. The preparation method according to claim 1, characterized in that: The mass ratio of material to liquid in mixture B is 1:1-1:

2.

9. Eucheuma kimchi obtained by the method for preparing fermented Eucheuma kimchi according to any one of claims 1 to 8.

10. The Eucheuma japonica kimchi according to claim 9, characterized in that: The content of nitrite in the Eucheuma japonicum kimchi is less than 4 mg / kg; and the Eucheuma japonicum kimchi contains phenolic substances.

Images