CN109170494B

CN109170494B - Novel artificial inoculation leaven cured beef and method thereof

Info

Publication number: CN109170494B
Application number: CN201810987194.7A
Authority: CN
Inventors: 何腊平; 刘亚兵; 李翠芹
Original assignee: Guizhou University
Current assignee: Guizhou University
Priority date: 2018-08-28
Filing date: 2018-08-28
Publication date: 2022-10-25
Anticipated expiration: 2038-08-28
Also published as: CN109170494A

Abstract

The invention discloses a novel artificially inoculated leaven cured beef and a method thereof. The fermented dried beef has unique flavor and good sense through the optimization of the formula of the leavening agent and the auxiliary materials and the optimization of the fermentation process. After the fermentation of the dried beef, the reinforced inoculation fermentation of the functional strain for reducing the cholesterol ensures that the cholesterol reduction of the dried beef reaches 30 percent and the nitrite content is basically not reduced after the fermentation of the dried beef. After the auxiliary materials are added, the content of polyunsaturated fatty acid and the content of dietary fiber of the cured beef are obviously improved, and the nutritional value of the cured beef is improved.

Description

Novel artificial inoculation leaven cured beef and method thereof

Technical Field

The invention relates to the technical field of food processing, in particular to a novel artificially inoculated leavening agent cured beef and a method thereof.

Background

The fermented dried beef is a traditional fermented meat product with national minority characteristics, and is deeply favored by consumers due to the characteristics of delicious taste, unique but not greasy flavor, long shelf life and the like. The defects of the quality of the fermented dried beef in China are mainly due to the defects of a leavening agent selected by the fermented dried beef, a formula of a fermentation auxiliary material and a processing technology condition factor, although certain progress is made in the aspect of flavor, the dried beef still mainly depends on a traditional natural fermentation processing mode in the processing technology, but the traditional dried beef production has the defects of unstable quality, long production period, easy pollution by pathogenic microorganisms, difficult standardized production, lack of depth in product development, inconsistent product quality and form with market requirements, inconsistent production technology with modern production, strong seasonality and regionality of production and the like, and the lactic acid bacteria and other excellent strains are necessary to be used for carrying out modern standardized production on the dried beef.

The leavening agent has great contribution to the formation of product flavor in the processing field of fermented meat products, and in developed countries in Europe and provinces in China, lactic acid bacteria are bacteria which are used as leavening agents at first because the addition of the lactic acid bacteria generates organic acid in the processing process and has certain inhibiting effect on other microorganisms of the meat products, such as putrefying bacteria, mould and the like. At present, according to the requirements of food safety standards in China, in order to control the fermentation and maturation process and inhibit the growth of other undesirable microorganisms, such as heterotypic fermentation bacteria, bacteria producing biogenic amines and pathogenic bacteria, leavening agents with suitable processing and processing properties have been used for producing dry fermented sausages. Research reports that the most beneficial leavening agent is separated from the traditional fermentation product, and the microorganisms can better adapt to the fermentation environment and can play a leading role in the microorganisms in the product. Under the conditions of natural fermentation, harmful substances can be generated, and the product quality is unstable, so that the fermentation of the meat products is necessary to artificially add a fermentation agent to ensure the safety of the products and standardize the products.

In the processing process of the fermented cured beef, a plurality of leavening agents are added in a mixing manner to endow the beef with delicious flavor and taste, improve the nutritive value of the beef and play a promoting role in treating some cases, and the leavening agents such as lactic acid bacteria are main dominant flora in human bodies and have important medical functions, such as reducing the cholesterol content of the human bodies; delaying the aging phenomenon of people, and the like. The research shows that the cholesterol is widely present in animal tissue cells, plays an important physiological role in human bodies, is one of important components forming the cells, can be converted into steroid hormone in vivo, and is a precursor substance for synthesizing vitamin D and bile acid. Cholesterol in vivo has two major sources, one being food and the other being endogenously synthesized. The unreasonable dietary habits are caused by the improvement of the living standard of people, and the excessive blood cholesterol content is caused to generate a health problem. High cholesterol content in a body can cause cardiovascular and cerebrovascular diseases such as atherosclerosis, coronary heart disease and the like, and the diseases seriously threaten human health. At present, the number of human deaths caused by cardiovascular and cerebrovascular diseases accounts for 29 percent of the total number of human deaths worldwide, and according to the prediction of the world health organization, the cardiovascular and cerebrovascular diseases are still the main cause of human death by 2030, and high cholesterol in serum is an important factor for causing cardiovascular and cerebrovascular diseases such as coronary heart disease, arteriosclerosis, cerebral apoplexy and the like. It has been found that hypercholesterolemic people are at a 3-fold higher risk of heart disease than their normal counterparts when compared to those with normal blood lipids.

Therefore, the research of fermented cured beef for reducing the serum cholesterol content in the body and promoting the health of people is of great significance, the artificial inoculation of a leaven for preparing the cured beef for preventing and treating the cardiovascular and cerebrovascular diseases is an effective and feasible research direction, people can not worry about high cholesterol when eating the cured beef, and on the contrary, the cured beef can be treated to a certain extent.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a novel artificially inoculated leaven dried beef and a method thereof, which remarkably shorten the fermentation time, are convenient for standardized production, have significant and unique flavor and good sense. The dried beef has low cholesterol content and basically no nitrite.

In order to realize the purpose, the invention is realized by the following technical scheme: a novel artificially inoculated starter beef jerky is prepared from 100 parts by weight of beef, 4-6 parts by weight of starter and 14.98 parts by weight of auxiliary materials; the leaven is cholesterol-lowering staphylococcus xylosus, aroma-producing yeast and lactobacillus plantarum.

In the leavening agent, the mass ratio of the cholesterol-lowering staphylococcus xylosus, the aroma-producing yeast and the lactobacillus plantarum is 1:2:2.

the auxiliary materials comprise 1.53 parts of glucose, 2 parts of salt, 1 part of crisp and numb, 0.075 part of tea polyphenol, 0.3 part of pepper, 2 parts of hot pepper, 0.075 part of monosodium glutamate, 4 parts of ginger and 4 parts of garlic.

The preparation method of the novel artificial inoculation starter cured beef comprises the following steps of:

1) Cleaning fresh beef, and cutting into strips with length of 2-3 cm;

2) Soaking the cut beef in white spirit for 18-25 minutes, adding a leavening agent into the beef, mixing, adding auxiliary materials, mixing for the second time, and repeatedly kneading the pickling materials until the surfaces of the beef strips are wet and softened;

3) Placing the meat strips mixed with the auxiliary materials into a thermostat isolated from air and light for low-temperature fermentation at 4 ℃ for 18-25 days;

4) Taking out the fermented meat strips, putting the meat strips into an oven for drying, and keeping the drying uniformity; taking out the dried meat strips immediately after the meat strips are dried to 26-28%, naturally cooling the meat strips in a clean and sanitary cooling chamber until the water content of the meat strips reaches 29-35%, and obtaining the dried beef meat strips;

5) And cooling the dried beef strips, and then carrying out vacuum packaging.

The drying temperature of the drying oven is 50-60 ℃, and the drying time is 6-10 h;

biological sample preservation used in the present invention: lactobacillus plantarum (Lactobacillus paracasei) GUFHSL-70 has been deposited in the China center for type culture Collection in 2016, 1 month and 4 days, with the deposit number of CCTCC M2016002. Xylococcus and aroma-producing yeast are commercially available strains.

Advantageous effects

Compared with the prior art, the fermented dried beef has unique flavor and good sense through the optimization of the formula of the leavening agent and the auxiliary materials and the optimization of the fermentation process. After the cured beef is fermented, the reinforced inoculation fermentation of the functional strain for reducing the cholesterol ensures that the cholesterol of the cured beef is reduced by 30 percent and the nitrite content is basically not reduced. After the auxiliary materials are added, the content of polyunsaturated fatty acid and the content of dietary fiber of the cured beef are obviously improved, and the nutritional value of the cured beef is improved.

Drawings

FIG. 1 is a graph of the effect of salt addition on the sensory score of cured beef fermentation;

FIG. 2 is a graph showing the interactive effect of fermentation time and fermentation temperature on the quality of cured beef

FIG. 3 is a graph showing the interaction of fermentation temperature and moisture content of cured beef on the quality of cured beef

FIG. 4 is a graph of response to the effect of interaction of roast moisture content and fermentation time on sensory score

FIG. 5 is a graph showing the relative (%) contents of volatile flavor components in cured beef before, during and after fermentation

FIG. 6 is a graph showing a comparison of the amounts of volatile flavor components of cured beef before, during and after fermentation

FIG. 7 is a scatter plot of the principal components of fermented cured beef at various stages of processing.

Detailed Description

The embodiment of the invention comprises the following steps: the novel artificial inoculation starter beef jerky comprises 100 parts of beef, 5 parts of starter and 14.98 parts of auxiliary materials by weight as preparation raw materials; the leaven is cholesterol-lowering staphylococcus xylosus, aroma-producing yeast and lactobacillus plantarum.

1) Cleaning fresh beef, and cutting into strips with the length of 2-3 cm;

2) Soaking the washed and cut beef in white spirit for 18-25 minutes, adding a leaven into the beef for mixing, then adding auxiliary materials for secondary mixing, and repeatedly kneading the pickling materials until the surfaces of the meat strips are wet and softened;

4) Taking out the fermented meat strips, putting the meat strips into an oven for drying, wherein the drying temperature of the oven is 55 ℃, the drying time is 8 hours, and the drying uniformity is kept; taking out the dried meat strips immediately after the meat strips are dried to 28%, placing the dried meat strips in a clean and sanitary cooling chamber for natural cooling until the water content of the meat strips reaches 30%, and obtaining the dried beef meat strips;

5) And cooling the dried beef strips, and then carrying out vacuum packaging.

Selection of the fermenting agent

(1) Cholesterol lowering ability of starter strains

The cholesterol removal capacity of the strain is measured by an OPA method, the cholesterol removal capacity of RS is the highest and is 24.31 percent, and the cholesterol removal rate of the strain SX is 18.45 percent, the cholesterol removal rate of MT is the lowest and is 9.28 percent

(2) Alcohol-resistant survival rate test

Uniformly coating white spirit on the surface layer of the drained beef, pickling the beef for 10 minutes in the white spirit (53 vol), adding ingredients such as salt, pepper, white granulated sugar and the like and a leavening agent, fully and uniformly mixing, finally inoculating fermentation bacteria suspension with equal concentration volume, uniformly mixing, putting the mixture at 4 ℃ for fermentation for 1d to determine the total number of bacterial colonies of the leavening agent, repeating the parallel determination for 3 times, and taking a strain without inoculation as a blank control.

The results show that the survival rate of the xylose grape bacteria is the lowest and is 19.57%, while the survival rates of the saccharomycetes and the lactic acid bacteria are higher and are respectively 34.99% and 38.68%, and the ratio of the fermenting agent in 3 is close to 1. The results show that after the fermentation product is soaked in the white spirit, the survival rate of the inoculated leaven and the auxiliary material mixed fermentation saccharomycetes and lactobacillus is high, and the proportion of the inoculated leaven and the auxiliary material mixed fermentation saccharomycetes and lactobacillus is relatively close to that of the inoculated leaven and the auxiliary material mixed fermentation lactobacilli during actual inoculation.

(3) Bacterial strain growth curve and acid production capacity

Lactic acid bacteria, saccharomyces cerevisiae and staphylococcus xylosus were inoculated into the corresponding liquid media at 3% (v/v), respectively, 36 h was cultured in a carbon dioxide incubator or an aerobic incubator set at 37 ℃, respectively, the absorbance values of the liquid media were measured at 0h, 4 h, 8h, … …, 36 h with an ultraviolet spectrophotometer at a timing of 600 nm, respectively, and the pH values of the strain culture solutions were measured with a pH meter at the corresponding time points.

The results show that the growth rate of the lactic acid bacteria strain of the leaven is fastest, the OD value is larger than that of the aroma-producing yeast and the xylose staphylococcus, and 3 leaven strains reach the stationary phase when the fermentation is cultured for 16 hours. The pH value of the culture medium corresponding to the increase of the fermentation time of the 3 strains is in a descending trend, and the lactic acid bacteria ferment glucose to generate lactic acid, so that the pH value of the lactic acid bacteria liquid is reduced fastest and can reach about 3.6 at the lowest, the aroma-producing yeast is used, the pH value can reach about 4.3 at the lowest, and the pH value of the xylose staphylococcus is used for reaching about 4.9 at the last. Therefore, the strain can be better suitable for the fermentation process of meat products and meet the requirements of meat leavening agents.

(4) Antagonism between starter strains

The fermentation agent lactobacillus (RS), the aroma-producing yeast (SX) and the xylose staphylococcus (MT) are crossed and streaked on an LB solid medium flat plate, the strains grow well, and no bacteriostasis phenomenon is generated at the crossed part, so that 3 strains of fermentation agent bacilli have no antagonism.

(5) Ability of the strains to resist freeze-drying

The strain dry powder after vacuum freeze drying is convenient to transport, the formed dry powder microorganism keeps relatively stable performance in a storage period, and 10% of skim milk is selected as a protective agent. And (3) calculating the viable bacteria rate before and after vacuum freeze drying, wherein the viable bacteria rate after freeze drying is not listed in the table, vacuum freeze drying is carried out, the viable bacteria rate of the leavening agent lactic acid bacteria (RS), the aroma-producing yeast (SX) and the xyloglucan (MT) after 5d preservation is respectively 95.22%,92.52% and 94.96%, and the viable bacteria rate of the leavening agent lactic acid bacteria (RS), the aroma-producing yeast (SX) and the xyloglucan (MT) after 30d preservation is respectively 90.02%,85.45% and 83.30%.

With the change of preservation time, the viable bacteria rate of the leaven is gradually reduced, wherein the initial viable bacteria number of the lactic acid bacteria is 9.22 plus or minus 0.02log CFU/g, and the viable bacteria number after 30 days of preservation at 4 ℃ is 8.30 plus or minus 0.01 log CFU/g. The initial viable count of the aroma-producing microzyme is 9.76 +/-0.18 log CFU/g, and the viable count after 30 days of storage at 4 ℃ is 8.34 +/-0.04 log CFU/g. The initial viable count of the staphylococcus xylosus is 8.92 plus or minus 0.03 log CFU/g, and the viable count after 30 days of preservation at 4 ℃ is 7.43 plus or minus 0.02log CFU/g. In the 3 kinds of leaven, the live bacteria rate of the lactic acid bacteria is higher than that of other strains along with the prolonging of the preservation time.

In conclusion, 3 leavening agents of xyloglucan, yeast and lactic acid bacteria are selected as the additive for fermenting the cured beef according to the proportion of 1 percent to 2 percent.

Single factor testing of adjuvants

The test was carried out according to the attached Table 2.

(1) Determination of salt addition amount

Under the condition that other raw and auxiliary materials and a processing technology are not changed, according to a basic formula, 0.025% of tea polyphenol, 2% of perilla frutescens seeds, 1.5% of glucose and 1%, 1.5%, 2%, 2.5% and 3% of salt are added into beef, the beef is fermented for 20 days, the beef is dried at 60 ℃ to prepare a finished product, and the content of the salt is determined by using an appearance scoring method after stir-frying. The results are shown in FIG. 1.

It can be seen from figure 1 that when the amount of salt added is less than 2%, the sensory score of the cured beef increased with the addition of the salt. When the amount of salt added is greater than 2%, the sensory score of the jerky decreases as the amount of salt added increases. When the adding amount of the salt is 1% or 3%, the adding amount of the salt is too high or too low, so that the salty taste of the dried beef is too heavy or too light, the taste and flavor of the dried beef are directly influenced, and the edible evaluation of the product is poor. While in the interval of 1.5% to 2.5%, the sensory score is better, and 2% makes the sensory score the best.

(2) Determination of Su Mazi addition

Under the condition that other raw and auxiliary materials and a processing technology are not changed, according to a basic formula, 0.025% of tea polyphenol, 1.5% of glucose, 2% of salt and 1%, 1.5%, 2%, 2.5% and 3% of perilla seeds are added into beef, the beef is fermented for 20 days, the beef is dried at 60 ℃ to prepare a finished product, and the content of Su Mazi is determined by using an appearance scoring method after stir-frying.

When the addition amount of the perilla frutescens seeds is 1% -1.5%, the sensory score of the product is increased along with the increase of the addition amount of Su Mazi, and the sensory score of the product is decreased along with the increase of the addition amount of Su Mazi when the addition amount of the perilla frutescens seeds is 1.5% -3%. The flavor of the product is not changed or is not obviously changed by less perilla seeds, the overall flavor of the product is influenced by more added perilla seeds, the product is not favored by people, and the sensory score is highest when the adding amount is 1.5%.

(3) Determination of the amount of glucose added

Under the condition that other raw and auxiliary materials and a processing technology are not changed, the beef is added into beef according to the proportion of 0.025 percent of tea polyphenol, 2 percent of salt, 2 percent of perilla frutescens seed and 0.5 percent of glucose, 1 percent, 1.5 percent, 2 percent and 2.5 percent of glucose, the beef is fermented for 20 days, the beef is dried at 60 ℃ to prepare a finished product, and the content of the glucose is determined by using an appearance scoring method after the beef is fried.

When the addition amount of glucose is 0.5-1%, the sensory score of the product increases with the addition amount of glucose, and when the addition amount of glucose is 1.5-2.5%, the sensory score of the product decreases with the addition amount of glucose. The addition of excessive sugar makes the taste of the product sweet and affects the taste of the product. When the addition amount of glucose is 1%, the sensory score is highest, and the taste of the product is good

(4) Influence of tea Polyphenol addition amount

Under the condition that other raw and auxiliary materials and a processing technology are not changed, according to a basic formula, 2% of salt, 2% of perilla seeds, 1.5% of glucose and 0.01%, 0.025%, 0.05%, 0.075% and 0.1% of tea polyphenol are added into beef, the beef is fermented for 20 days, a finished product is prepared by drying at 60 ℃, and the content of the tea polyphenol is determined by a perception scoring method after the beef is fried.

When the addition amount of the tea polyphenol is 0.025% -0.075%, the sensory score of the product is increased along with the increase of the addition amount of the tea polyphenol, and when the addition amount of the tea polyphenol is 0.075% -0.125%, the sensory score of the product is reduced along with the increase of the addition amount of the tea polyphenol. The increase of the addition amount of the tea polyphenol inhibits the oxidative deterioration of the product, so that the taste and the flavor of the product are improved. And the sensory score of the product is highest at 0.075%.

When the addition amount of the tea polyphenol is 0.025-0.075%, the sensory score of the product is increased along with the increase of the addition amount of the tea polyphenol, and when the addition amount is 0.075-0.125%, the sensory score of the product is reduced along with the increase of the addition amount of the tea polyphenol. The increase of the addition amount of the tea polyphenol inhibits the oxidative deterioration of the product, so that the taste and the flavor of the product are improved. And since 0.075% has the highest sensory score, the addition amounts of 0.05%, 0.075% and 0.1% of tea polyphenols were selected as the addition amounts in the orthogonal experiment.

5) Quadrature test

The starting salt (a), perilla seeds (B), tea polyphenols (C) and glucose (D) 4 factor 3 levels were selected for orthogonal experiments. Orthogonal table selection L ₉ (3 ⁴ ). The results are shown in the attached Table 3.

The magnitude order shown by the range calculation results in attached table 3 is: 9.5 > 6.5=6.5 > 2 ⇒ salt > tea polyphenol = Su Mazi > glucose, the influencing factor in the experiment is: salt > tea polyphenols = perilla seeds > glucose.

The most significant influence on the sensory perception of the fermented cured beef is the addition amount of the table salt, and the optimal level of each factor is A ₂ B ₁ C ₂ D ₃ Is the 4 th group with the highest sensory score in the orthogonal experimental group, so the optimal process parameters of the fermented dried beef are 2% of salt, 0.075% of tea polyphenol, su Mazi% and 1.5% of glucose.

As can be seen from the attached Table 4, the addition amount of table salt in the experiment has the greatest influence on the dried beef, the taste of the dried beef is directly influenced because salty taste has great influence on human taste, while the addition amount of Su Mazi is secondly because Su Mazi has very attractive fragrance after being fried, the smell of the dried beef is directly influenced, the influence of glucose and tea polyphenol is small, and the influence is very small, so that the glucose is decomposed and utilized by microorganisms in the fermentation process, and the residual quantity is small. The dried beef has low moisture content, good storage condition and no rancidity and deterioration after vacuum packaging, and the influence of the tea polyphenol on the dried beef is not obvious.

6) BBD assay

The results of the orthogonal experiments show that the important factors influencing the product quality are the dosage of the salt, su Mazi and glucose.

TABLE 5 factor levels for BBD design

Salt, su Mazi and glucose are represented by A, B and C, respectively, and the high, medium and low levels of the factor are encoded by +1, 0 and-1, respectively, according to the equation Xi = (Xr-X0)/$ X, thereby obtaining the factor levels and codes for BBD design (attached table 5). The results are shown in Table 6.

Formula after calculation according to coding factor:

sensory rating = +90.20+0.13 ^ Z1+0.50 ^ Z2+0.88 ^ Z3+2.25 ^ Z1^ Z3-4.48 ^ Z1^2-7.23 ^ Z2^2-4.47 ^ Z3^2

According to a formula calculated by actual factors:

k sensory rating = +90.20000+0.12500 x +0.50000 y +0.87500 z +2.25000 x z-4.47500 x ^2-7.22500 y ^2-4.47500 z ^2

And displaying according to the calculation result:

the optimization parameters are as follows: x salt =2.0, y perilla seed =1.0, z glucose =1.53, and the predicted value =90.3

The regression prediction model of K is obtained by performing response surface analysis based on the experimental results, and equation analysis of the regression equation is performed on the regression prediction model of K (see table 7).

Regression model p of K<0.0001, the regression model is obvious and fits well, and the experiment is reliable. f mismatch term =0.5082 < f _（0.05） (7,3) =8.88, p mismatch =0.5082 > 0.05, p model < 0.05, signifying insignificant mismatch terms, small experimental error, AC, a ² , B ² , C ² The item has obvious effect on sensory scoreThis has a significant impact. And influence factor B ² ＞A ² =C ² ＞AC。

7) Verification test

Experimental results obtained by analysis of the differences: the optimal technological parameters of the fermented dried beef are 2% of salt, 0.075% of tea polyphenol, su Mazi% and 1.5% of glucose, and verification experiments are carried out. And (4) carrying out sensory evaluation. Three groups of parallel tests are respectively carried out to obtain results, which show that the sensory average value obtained by orthogonal optimization combination is 89.3, and the results are credible.

And (3) carrying out a verification experiment on the analysis result of the BBD experiment: the optimal technological parameters of the cured beef fermentation auxiliary material are x salt =2.0, y perilla frutescens =1.0 and z glucose =1.53, and three groups of parallel tests respectively obtain results, which show that the sensory average value obtained by BBD optimization combination is 90.6, and the BBD optimization result is reasonable.

And 5 factors influencing the technological conditions of the fermented cattle jerky, such as fermentation temperature, baking temperature, fermentation time, water content and edible vinegar addition amount, performing Plackett-Burman and Box-Behnken response surface tests, and obtaining the optimal technological conditions of the fermented cattle jerky by taking sensory test as an evaluation index.

1) Auxiliary material process formula

1.53 percent of glucose, 2 percent of salt, 1 percent of crisp sesame, 0.075 percent of tea polyphenol, 0.3 percent of pepper, 2 percent of hot pepper, 0.075 percent of monosodium glutamate, 4 percent of ginger and 4 percent of garlic.

2) Single factor experiment

(1) Selection of fermentation temperature

Mixing the materials according to the optimized process formula to ferment beef, respectively fermenting the mixed beef at 0 ℃,4 ℃,8 ℃, 12 ℃ and 16 ℃ for 15d, baking at 55 ℃, carrying out sensory evaluation when the moisture content of the beef is determined to be about 30% by timing sampling, and determining the optimal fermentation temperature according to the sensory evaluation result.

The sensory score of the dried beef quality tends to increase and decrease along with the change of the fermentation temperature of the dried beef, the fermentation temperature is highest at 10 ℃ and lowest at 20 ℃, possibly because the low temperature is difficult to volatilize some volatile substances in the fermented dried beef so as to have certain influence on the sensory score, and after 10 ℃, the sensory score tends to decrease, possibly because some volatile substances are volatilized before the sensory score of the fermented dried beef so as to reduce the flavor of the fermented dried beef, so that the sensory score tends to decrease. The fermentation process of the product is accelerated due to the over-high fermentation temperature, the fermentation speed is increased, the sour taste of the fermented beef is too thick, the texture of the product is poor, and the sensory score is low.

(2) Selection of baking temperature

Mixing materials according to an optimized process formula to ferment the beef, fermenting the mixed beef at 4 ℃ for 15d, taking out, respectively baking at 45 ℃,50 ℃,55 ℃,60 ℃ and 65 ℃, performing sensory evaluation when the moisture content of the beef is determined to be about 30% by timing sampling, and determining the optimal baking temperature according to sensory evaluation results.

Along with the change of the baking temperature of the cured beef, the sensory score of the cured beef quality tends to rise firstly and then fall, the baking temperature is highest at 55 ℃, lowest at 45 ℃ and 65 ℃, probably due to low-temperature baking, the time required for the cured beef is longer, and in addition, the moisture of the cured beef per se is slower, so that the cured beef is poorer in quality, the difference between the surface layer and the internal moisture content of the fermented cured beef is reduced, the internal texture of the fermented cured beef is harder, and the chewiness of the cured beef is not facilitated. And if the baking temperature is too high, the baking time of the fermented dried beef is relatively short, which may cause the surface of the fermented dried beef to be hard, the color change difference is large, the moisture content on the surface and the moisture content in the fermented dried beef are different, the taste of the fermented dried beef is seriously influenced, and the sensory score is relatively low.

(3) Selection of fermentation time

Mixing the materials according to the optimized process formula to ferment the beef, putting the mixed beef at 4 ℃ to ferment for 5d, 10d, 15d, 20d and 25d respectively, taking out the beef, baking the beef at 55 ℃, performing sensory evaluation when the moisture content of the beef is determined to be about 30% by timing sampling, and determining the optimal fermentation time according to the sensory evaluation result.

With the change of the fermentation time of the cured beef, the sensory score of the cured beef quality tends to rise firstly and then fall, the sensory score is highest when the fermentation time is 10-15d, and is lowest when the fermentation time is 25d, and the fermenting agent and other microorganisms on the surface and inside of the cured beef can be rotten and stacked, even the off-flavor condition can occur, so that the quality is poor, the taste of the fermented cured beef is seriously influenced, and the sensory score is lower.

(4) Selection of the addition amount of edible vinegar

The beef is fermented by mixing the materials according to the optimized process formula, 0.5%, 1%, 1.5%, 2% and 2.5% of edible vinegar is respectively added, the beef is fermented at the temperature of 4 ℃ for 15d and baked at the temperature of 55 ℃, sensory evaluation is carried out when the moisture content of the beef is determined to be about 30% by timing sampling, the pH value of the beef is determined, and the optimal pH value is determined according to sensory evaluation results.

With the increasing of the adding amount of the edible vinegar, the sensory score of the fermented cured beef tends to increase firstly and then decrease, the sensory score of the fermented cured beef is highest when the adding amount of the edible vinegar is 1.0%, the sensory score of the fermented cured beef is lowest when the adding amount of the edible vinegar is 2.5%, probably because the lower adding amount of the edible vinegar can endow the cured beef with certain flavor, and the fermented cured beef becomes very sour due to the large amount of the edible vinegar, the pH value is very low, the taste becomes poor, and the sensory score is lower.

(5) Selection of the drying moisture content

Mixing the materials according to the optimized process formula to ferment beef, fermenting the mixed beef at the temperature of 4 ℃ for 15d, baking at the temperature of 55 ℃, respectively baking until the cooled moisture content is 20%, 30%, 40%, 50% and 60%, and carrying out sensory evaluation, and determining the optimal moisture content according to the sensory evaluation result.

With the continuous increase of the moisture content of the dried cured beef, the sensory score of the quality of the fermented cured beef is in a trend of increasing firstly and then decreasing, the sensory score of the fermented cured beef is the highest when the moisture content of the cooled cured beef is controlled to be 30%, and the sensory score is the lowest when the moisture content of the cooled cured beef is 60%.

2) Plackett-Burman test

According to the levels of all factors determined by a previous single-factor pre-test, a Plackett-Burman test design with the test times N =12 is selected, and the fermentation temperature, the baking temperature, the fermentation time, the water content and the edible vinegar addition amount which influence the quality of the fermented beef jerky are 5A factor is considered, and each factor takes two levels of high and low, wherein the high level is 1.25 times of the low level. Additionally setting X in six blank item corresponding tables ₃ 、X ₆ 、X ₈ 、X ₉ 、X ₁₀ And X ₁₁ For estimating trial errors. The test factors and levels are shown in the attached Table 8. The results of the Plackett-Burnman test and the analysis of variance are shown in attached Table 9 and 10.

It can be seen from the attached tables 9 and 10 that the p-value of the experimental model is less than 0.05, indicating that all models are significant and fit well. And then, determining the fermentation temperature, the fermentation time and the moisture content as main factors influencing the quality of the cured beef according to sensory evaluation indexes, and performing further optimization tests by taking the three factors as research objects.

3) Steepest hill climbing test

And designing a climbing direction and a step length according to the result of the last Plackett-Burman test, changing the fermentation temperature, the baking temperature, the fermentation time, the edible vinegar and the moisture content according to a certain gradient, and measuring sensory scores so as to determine the optimal variation range of the three factors of the purple fermentation temperature, the fermentation time and the moisture content.

The climbing direction and step length of 3 important factors are set according to the Plackett-Burnman test result, the result is not obviously influenced, the fermentation temperature is 10 ℃, the fermentation time is 15d, the water content is 30 percent according to the positive and negative effects of the factors and the single-factor test result, and the test design and the result are shown in the attached table 11.

As can be seen from the attached Table 11, the sensory scores of the fermented foods showed a tendency of increasing first and then decreasing with the changes of the fermentation temperature, the fermentation time and the moisture content, and the sensory scores were the best when the fermentation temperature, the fermentation time and the moisture content were 10 ℃ and 15d and 30%, respectively, indicating that they were relatively close to the optimal response region. Therefore, the next test will take the fermentation temperature of 10 ℃, fermentation time of 15d and water content of 30% as the center point of the test, and perform the response surface test.

4) Box-Behnken response surface test

The invention adopts a Box-Behnken method, which is a test method suitable for optimizing 2~5 factors, 3 process parameters and reasonable levels thereof are determined by the above two steps of tests, then a response surface test is carried out by taking the 3 process parameters as independent variables and taking the sensory score of fermented cattle jerky as a response value, and the test factors and the levels are shown in an attached table 12. The zero point test was repeated 5 times to examine the test error.

Regression analysis was performed on the test data in attached table 13 using Design Expert 8.0.6 software to obtain a quadratic regression model with each response value as a target function:

sensory score =92.40-0.25A-0.75B +0.25C +0.00AB +3.00AC +1.50BC-3.70A ² -4.20B ² -3.70C ²

Note: A. b, C is the argument code value; coded value = (actual value-center value)/step size

Analysis of variance was performed for each model and the results are shown in the attached Table 14. Of all modelsp value<0.05Of significance, but of irreducibilityp Value of>0.0Not significant, R of model ² >And 0.85, which shows that the model fitting degree of the test is good, the test error is small, and the method can be used for predicting the fermented cattle jerk process parameters.

5) Response surface analysis

And drawing a response surface (shown in the attached figures 2-4) for visual analysis, and researching the interaction between related variables.

Fig. 2 shows the interaction effect of fermentation time and fermentation temperature on the quality of the dried beef, and as can be seen from the figure, the interaction effect is remarkable, and the sensory score of the fermented dried beef is in an increasing trend along with the increase of the fermentation temperature and the fermentation time, because the increase of the temperature causes the reduction of water in the dried beef in the same time, possibly related to volatile flavor in the dried beef, so that certain flavor is presented along with the increase of the temperature, and the sensory score is increased.

Fig. 3 shows the interaction effect of the fermentation temperature and the moisture content of the cured beef on the quality of the cured beef, and it can be seen from the figure that the interaction effect is significant, the sensory score of the fermented cured beef shows a trend of rising first and then falling along with the increase of the fermentation temperature and the moisture content, because the change of the moisture content can cause the change of some flavor substances, certain flavor components can be effectively retained in a certain range, and certain volatile substances can be volatilized along with the rise of the temperature to show certain flavor, so that the sensory score is increased.

FIG. 4 shows the interaction of fermentation time and moisture content on the sensory score of cured beef, and it can be seen from the response surface chart that the influence of fermentation time on sensory score is most significant, and the sensory score is increased and then decreased with the increase of fermentation time, because the fermentation time is proper, the juiciness and taste of cured beef can be increased, but the fermentation agent of cured beef is dead by a large amount of accumulated strains after a certain time, the taste of cured beef can be changed, and the forming degree and taste of cured beef are deteriorated

Therefore, sensory score is reduced, certain flavor substances with good moisture content are well reserved, and if the temperature is too high, the flavor of the cured beef is not coordinated, the sensory score is reduced, and the mouthfeel is influenced.

6) Determination and verification experiment of optimal formula

The sensory score is taken as a response value, the optimal process parameters predicted by a regression model are that the fermentation temperature is 9.83 ℃, the fermentation time is 14.56 d, the water content is controlled to be 29.99%, and the sensory score of the fermented jerky product produced under the condition is 92.44. In order to check the reliability of the result obtained by the response surface method, considering the convenience of actual operation, the parameters are corrected as follows: the fermentation temperature is 10 ℃, the fermentation time is 15d, the water content is controlled to be 30%, a verification experiment is carried out under the conditions, through 6 parallel experiments, the actually measured sensory score is 92, the relative error is 0.55-1.60%, and the relative error is very close to the predicted value, so that the process parameters of the fermented dried beef obtained by the response surface analysis method are true and reliable.

Change of cholesterol and nitrite content before and after fermentation of cured beef

The change in cholesterol and nitrite content before and after the fermentation of cured beef was measured by the o-phthalaldehyde method, and the results are shown in the attached table 15. The attached table 15 shows that the cholesterol content of the fermented beef jerky is reduced by about 30% compared with that before the fermentation, and is further reduced after the baking.

TABLE 15 Cholesterol content variation (mg/100 g) of fermented beef jerky at each stage of fermentation

In addition, the nitrite content in the cured beef is measured according to GB 5009.33-2016 (determination of nitrite and nitrate in food), and the result shows that the nitrite content before the cured beef is fermented is 2.47 mug/Kg, and the nitrite content after the fermentation cannot be detected.

Flavor change before and after fermentation of cured beef

The volatile component analysis of fermented dried beef adopts Solid Phase Microextraction (SPME), 6g of sample is weighed, cut into about 2mm to obtain particles, and the particles are put into an extraction bottle, sealed and balanced for 20min at 50 ℃. A solid-phase extraction injector was inserted into the headspace of the extraction flask and extracted for 40min. The extractor was then transferred to a GC-MS instrument and desorbed for 7min at 250 ℃ while the instrument was started to collect data.

Gas spectrum conditions are as follows: the capillary column is a DB-WAX column, and the temperature is programmed: the initial temperature is 40 deg.C, maintained for 3min, then raised to 200 deg.C at a rate of 5 deg.C/min, and then raised for 10 deg.C min ^-1 Is raised to 230 ℃ and maintained

3min, gasification at room temperature 25 ℃: the carrier gas is He, the flow rate is 6mL/min, and the split ratio is 5:1.

Mass spectrum conditions: the ionization mode is EI, the electron energy is 70eV, the interface temperature is 250 ℃, the transmission line temperature is 280 ℃, the ion source temperature is 230 ℃, the quadrupole rod temperature is 150 ℃, and the scanning range is 55-500m/z.

1) Detection result of volatile flavor component

The volatile flavour components of the fermented cured beef at the different processing stages are shown in the attached table 16.

TABLE 16 ingredient Table of volatile flavor substances of fermented jerky

As can be seen from the attached tables 16-18, the differences in the types of the volatile flavor components of cured beef before, during, after and after fermentation and the differences in the relative contents were large. The types of volatile flavor components of the cured beef in the fermentation are more than those before and after the fermentation, and may be related to the decomposition and oxidation change of macromolecular substances in the fermentation process and the generation of substances by the self-metabolism of microorganisms. The types of flavor substances of the cured beef are obviously reduced after fermentation through a baking process, and other compounds are formed probably due to volatilization or chemical reaction of part of flavor substances in the beef in the heating process. Meanwhile, the types of flavor substances of cured beef in the fermentation process are obviously higher than those of the cured beef before and after the fermentation process, and the relative contents of the flavor substances are not greatly different, which is probably due to the fact that the starter is added in a test group, and the starter has a good aroma generating function and contributes to improving the aroma of products. The types of the flavor substances after baking are obviously reduced, and a part of flavor substances are volatilized along with the rise of the baking temperature, so that a part of flavor substances are reserved.

As can be seen from the attached tables 16 to 18, 43 types of volatile flavors of cured beef before fermentation, 56 types of volatile flavors of cured beef during fermentation, 45 types of volatile flavors of cured beef after fermentation, and 40 types of volatile flavors of cured beef were detected together. The fermentation medium comprises 4 kinds of alcohols, 18 kinds of olefins, 5 kinds of alkanes, 3 kinds of ethers, 1 kind of acids, 2 kinds of aromatic hydrocarbons and 3 kinds of others before fermentation; the fermentation comprises 7 alcohols, 26 alkenes, 3 alkanes, 7 esters, 7 ethers, 1 ketone, 5 ethers, 4 aromatics and other 7; the fermented product comprises 6 alcohols, 18 olefins, 2 alkanes, 6 esters, 1 aldehyde, 5 ethers, 2 ketones, 2 aromatics and 2 others; the baked product comprises 5 kinds of alcohols, 17 kinds of olefins, 2 kinds of alkanes, 5 kinds of esters, 0 kind of aldehydes, 5 kinds of ethers, 1 kind of ketones, 2 kinds of aromatic hydrocarbons and 3 kinds of others. Before and during fermentation, the types are not complete, and after fermentation, the types are complete, which indicates that the cured beef forms certain flavor in the fermentation process, and the leavening agent possibly endows the cured beef with the flavor, and after baking, the types of flavor substances are reduced, and mainly a part of flavor substances are volatilized due to the rising of baking temperature.

As can be seen from the attached tables 16-18 and the attached figures 5-6, there are certain differences in the relative contents of the volatile substances before fermentation, during fermentation, after fermentation and after baking, the highest relative content of alcohol before fermentation is 13.63%, and the lowest relative contents of alcohol after fermentation and after baking are respectively: 6.29 percent and 8.83 percent, and the possible reasons are mainly caused by utilization and volatilization of microorganisms, wherein the tendency is that the microorganism is reduced before fermentation, in fermentation and after fermentation; the total relative content of the olefins is increased and then decreased before fermentation, during fermentation, after fermentation and after baking, and the olefin content after fermentation is up to 19.6 percent, which is probably the reason of fermentation of the leaven; the total relative content of volatile flavour substances in the fermentation was at most 103.7% and after baking was at least 91.41%, in terms of total composition, mainly due to the fact that baking causes a part of the volatile substances to evaporate with increasing temperature. Before, during, after and after fermentation, the volatile substance components have certain differences, and it is known from the table that the number of olefins is the largest and tends to increase first and then decrease, and that alcohols, aldehydes, aromatics and other species also tend to increase first and then decrease. At different processing stages, the types of various volatile substances tend to increase and then decrease, the maximum of 60 types are detected in fermentation, and the minimum of 43 types are detected after baking, which indicates that a part of style substances are volatilized after baking.

In different processing stages, due to different leavening agents and processing technologies, the flavors presented in different stages have certain differences, and meanwhile, the flavors of the beef jerky are similar or identical to those of other researchers. It can be seen that different meat types, different processing techniques and different adjuvants may produce products with different flavors.

2) Analysis of volatile flavor main components of fermented cured beef before and after processing

The volatile substances before, during, after and after fermentation are subjected to main component analysis by SPSS 20.0 software, and the relative contents of main volatile aroma components obtained from 4 samples before, during, after and after fermentation are taken as variables, as can be seen from Table 5, the main component 1 accounts for 98.12% of the total variance contribution rate, the main component 2 accounts for 1.34% of the total variance contribution rate, the cumulative contribution rate is 99.46%, and the two main components already contain the vast majority of information of fermented cattle jerk, so that the first 2 main component components are selected for subsequent component analysis.

As is clear from the attached Table 19, the index reflected by the 1 st main component is mainly ethanol, camphene, hexadiene, 1-B-bisabolene, curcumene, n-hexane, anethole, alkane-based substances and olefin-based substances other than ethyl decanoate. The catalyst is highly positively correlated with ethanol, camphene, hexadiene, 1-B-bisabolene, curcumene, n-hexane and other anethole substances, the ethanol and the ethyl decanoate have the largest contribution rate to the 1 st component, the loading amounts are 1.41 and 9.28 respectively, the cyclohexanol, the ethyl myristate and the methylheptenone have the smallest contribution rate to the 1 st component, and the loading amounts are all-0.19; the 2 nd main component reflects indexes of sabinene, bisabolene, n-hexane and anethole and points to olefinic substances and other substances. The most contributing rate to the 2 nd component is sabinene and bisabolene, the load capacity is 11.01 and 10.05 respectively, the least contributing rate to the 2 nd component is ethanol, and the load capacity is-0.19; therefore, the main aroma substances of the fermented dried beef can be synthesized into alkane substances, olefin substances, other substances and the like, and the composition of the aroma components of the dried beef in different processing stages can be evaluated by using the indexes.

As shown in the attached figure 7, volatile substances before fermentation, during fermentation, after fermentation and after baking are divided into 2 types according to the distance, the beef jerky flavor has certain difference in different processing stages, the substances before fermentation, during fermentation and after fermentation are classified into one type when the distances are close, the substances after baking are classified into one type when the distances are close, the types of the flavor substances are not greatly different in different fermentation stages, but the flavor substances after baking are obviously changed, mainly along with the change of baking temperature, a part of substances of the beef jerky volatilizes or the beef jerky tissues are changed, so the effect of changing the flavor substances after baking is achieved. In conclusion, ethanol, camphene, hexadiene, bisabolene, curcumene, n-hexane, anethole, sabinene and bisabolene are characteristic flavor components of fermented dried beef, and have important contribution to the formation of the fermented dried beef before, after and after the fermentation. Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The novel artificial inoculation starter dried beef is characterized by comprising the following components in parts by mass: 100 parts of beef, 4-6 parts of leavening agent and 14.98 parts of auxiliary material;

the leaven is cholesterol-lowering staphylococcus xylosus, aroma-producing yeast and lactobacillus plantarum; the lactobacillus plantarum is lactobacillus plantarum GUFHSL-70 which is preserved in China center for type culture Collection and has the preservation number of CCTCCM 2016002;

the mass ratio of the cholesterol-lowering staphylococcus xylosus to the aroma-producing yeast to the lactobacillus plantarum is 1:2:2; the auxiliary materials comprise, by mass, 1.53 parts of glucose, 2 parts of salt, 1 part of crisp sesame, 0.075 part of tea polyphenol, 0.3 part of pepper, 2 parts of pepper, 0.075 part of monosodium glutamate, 4 parts of ginger and 4 parts of garlic;

the preparation method of the novel artificial inoculation starter dry beef comprises the following steps:

1) Cleaning fresh beef, and cutting into strips with length of 2-3 cm;

4) Taking out the fermented meat strips, putting the meat strips into an oven for drying, and keeping the drying uniformity; immediately taking out the dried meat strips after the water content is 26-28%, naturally cooling in a clean and sanitary cooling chamber until the water content of the meat strips reaches 29-35%, and obtaining the dried beef meat strips;

5) And cooling the dried beef strips, and then carrying out vacuum packaging.

2. The method for preparing the novel artificially inoculated starter niuhuba as claimed in claim 1, comprises the following steps:

1) Cleaning fresh beef, and cutting into strips with length of 2-3 cm;

4) Taking out the fermented meat strips, putting the meat strips into an oven for drying, and keeping the drying uniformity; immediately taking out the dried meat strips after the water content is 26-28%, naturally cooling the dried meat strips in a clean and sanitary cooling chamber until the water content of the meat strips reaches 29-35%, and obtaining the dried beef meat strips;

5) And cooling the dried beef strips, and then carrying out vacuum packaging.

3. The preparation method of claim 2, wherein the drying temperature of the oven is 50-60 ℃ and the drying time is 6-10h.