CN114617225A

CN114617225A - Coarse cereal noodles and preparation method thereof

Info

Publication number: CN114617225A
Application number: CN202210303952.5A
Authority: CN
Inventors: 薛勇; 刘丽君; 索南卓玛; 沈群
Original assignee: China Agricultural University
Current assignee: China Agricultural University
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2022-06-14
Anticipated expiration: 2042-03-25
Also published as: CN114617225B

Abstract

The invention provides coarse cereal noodles which are made of flour, wherein the flour comprises 18-22 parts by mass of wheat flour and 78-85 parts by mass of coarse cereal powder, and the coarse cereal powder comprises millet, coix seed and mung bean powder. The invention analyzes and comprehensively considers the basic components, the particle size distribution, the hydration characteristic, the digestion characteristic and the protein nutritive value of eight coarse cereals and selects millet, coix seed and mung bean as the raw materials for preparing the high-content coarse cereal noodles. The optimal dietary fiber content, particle size distribution, damaged starch, water solubility and cooking loss conditions are obtained through research, and the quality of the noodles is ensured.

Description

Coarse cereal noodles and preparation method thereof

Technical Field

The invention belongs to the technical field of nutritional foods, and particularly relates to a coarse cereal staple food and a preparation method thereof.

Background

The coarse cereals generally refer to all grain crops except five major food crops of rice, wheat, soybean, corn and potato, and are mainly divided into three types: cereals (such as semen Avenae Nudae, fructus Hordei vulgaris, herba Avenae Fatuae, rhizoma et radix Veratri, Coicis semen, semen Fagopyri Esculenti, jowar, etc.), beans (such as semen Phaseoli Radiati, semen Vignae sinensis, semen Ciceris Arietini, etc.), and potatoes (such as purple sweet potato, rhizoma Amorphophalli, sweet potato, etc.). The coarse cereals are taken as one of daily diets, contain rich nutrient substances, protein, unsaturated fatty acid, vitamins, mineral substances, dietary fibers and unique bioactive substances, have high resistant starch content and complete various nutrients, and are ideal food materials for people with glycolipid metabolic disorders. The coarse cereals are simple in processing method, a lot of nutritional ingredients such as starch, inorganic salt, cellulose and B vitamins are reserved, and compared with the coarse cereals, a part of nutritional ingredients are lost in the grain processing process of the white rice and the fine white flour. In Chinese resident dietary guidelines (2021), it is pointed out that various foods and grains are the main characteristics of balanced dietary patterns, and it is proposed to clearly match the coarse grains and the fine grains, and it is recommended to eat 50-150g of coarse grains every day. The protein content of the coarse cereals is about 10-18 percent, which is far higher than that of the large crops such as rice, wheat and the like, and the amino acid composition is relatively complete and balanced. The coarse cereals have high content of unsaturated fatty acid, especially essential fatty acid such as linoleic acid and linolenic acid, and have effects of regulating lipid metabolism, reducing blood lipid, and preventing cardiovascular diseases. A large amount of dietary fibers in the coarse cereals can effectively promote intestinal tract movement, regulate gastrointestinal functions and reduce cholesterol and glucose levels. Meanwhile, abundant vitamin B group and mineral substances such as calcium, iron, zinc, magnesium, selenium and the like can promote the regulation of human body functions, enhance the immunity of the organism and reduce the occurrence of coronary heart disease.

The coarse cereals are good nutrition-enhancing raw materials of the noodles due to rich vitamins and mineral substances, high-quality protein and amino acid and a large amount of dietary fiber; the coarse cereals also contain special pigment and special flavor, and are natural colorant and flavoring agent of the processed noodles. However, the protein composition and structure of the coarse cereal flour are different from those of wheat protein, and no gluten protein is contained, so that a good gluten network structure is difficult to form when the flour is made into a dough, and the noodles are poor in viscoelasticity, flexibility, dough quality and taste, so that the development and application of the coarse cereals in the aspect of noodle processing are greatly limited. At present, the coarse cereals are matched with wheat flour when being used for processing noodles, the addition amount of the coarse cereal flour is about 30 percent, or modifiers (xanthan gum, wheat gluten, konjac flour and the like) are added to improve the content of the coarse cereals and improve the cooking quality of the noodles. The higher the content of coarse cereals, the poorer the palatability of the processed noodles, and the easier it is to make soup turbid. Therefore, how to organically combine the coarse cereals and the noodles to develop high-quality coarse cereal noodle products is an important subject to be researched in the flour product industry.

Disclosure of Invention

In order to solve the problems in the prior art, the invention obtains the types of the coarse cereals with good processing adaptability by screening, optimizes the processing technological condition parameters of the coarse cereal noodles through a response surface experiment, and provides the coarse cereal noodles with relatively high sensory quality and excellent apparent state, toughness, mouth feeling and smoothness.

The second purpose of the invention is to provide a preparation method of the coarse cereal noodles.

The technical scheme for realizing the above purpose of the invention is as follows:

the coarse cereal noodles are made of flour, wherein the flour comprises 18-22 parts by mass of wheat flour and 78-85 parts by mass of coarse cereal powder, and the coarse cereal powder comprises millet, coix seed and mung bean powder.

Wherein the mass ratio of the millet to the coix seed to the mung bean is 1-2: 2-3: 4.

Preferably, the flour of the coarse cereal noodles is prepared from the following components in mass ratio of (1.8-2.2) to (1.4-1.6): (2.4-2.6) to 4. For example, it may be 2: 1.5: 2.5: 4.

The preparation method of the coarse cereal noodles comprises the following steps:

1) grinding: grinding the coarse cereals into powder respectively, and sieving the powder through a sieve of 50 meshes to 140 meshes to obtain coarse cereal powder;

2) kneading: the coarse cereal flour and the wheat flour are mixed into dough, the technological parameters of the dough mixing are 35-50 parts of water (namely 50 parts of water is added when 100 parts of flour is added), the water temperature is 30-70 ℃, the fermentation time is 0-20 min,

3) making noodles: and preparing the kneaded dough into noodles.

One preferable technical scheme of the invention is that the technological parameters of dough kneading are as follows: adding water in an amount of 40-42%, heating water at 55-59 ℃, and fermenting for 11-15 min.

Further, pretreating the coarse cereal powder (called as raw powder in a pretreatment process) obtained by milling, wherein the pretreatment is one or more of superfine grinding, microwave treatment, extrusion puffing and spray drying;

the superfine grinding comprises the following steps: placing the coarse cereal powder obtained by milling into a ball mill, and carrying out ball milling for 100-150 min at the rotating speed of 300-500 r/min and the ball-to-material ratio of (3-5): 1;

the microwave treatment comprises the following steps: intermittently heating the coarse cereal powder obtained by grinding for 2-5 min at 700W and 2000-3000 MHz.

The extrusion swelling is as follows: adjusting the water content of the coarse cereal powder obtained by milling to 15-20%, preheating by an extruder, extruding, and then crushing;

the spray drying comprises the following steps: and preparing the coarse cereal powder obtained by milling into a solution with the concentration of feed liquid of 2-10%, and performing spray drying at the temperature of an air inlet of 120-160 ℃.

Wherein the microwave treatment comprises the following steps: intermittently heating the coarse cereal powder at 700W and 2450MHz with medium and high fire for 3min for 60s each time.

Further preferably, the pretreatment is spray drying, wherein coarse cereal powder is prepared into a solution with the feed liquid concentration of 4-6%, the solution is uniformly stirred, then is subjected to colloid milling, and is filtered by using a standard sieve of 80-120 meshes; and carrying out spray drying at the temperature of an air inlet of 130-150 ℃.

Another preferable technical scheme of the present invention is that the prepared minor cereal noodles are quickly frozen (quick frozen) after being cooked, the freezing temperature is-25 ℃ to-45 ℃, and frozen cooked noodles (FCN, also called moisturizing cooked noodles) are obtained.

Other freezing temperatures are possible, even up to-80 degrees, but energy consumption, cost and quality variations are taken into account.

Furthermore, the prepared coarse cereal noodles are subjected to noodle boiling, showering cooling and quick freezing for 25-40 min, wherein the temperature of the quick freezing is-38 ℃ to-42 ℃, and the frozen cooked noodles are obtained.

The time for quick freezing is more preferably 30 min.

The invention has the beneficial effects that:

the invention analyzes and comprehensively considers the basic components, the particle size distribution, the hydration characteristic, the digestion characteristic and the protein nutritive value of eight coarse cereals and selects millet, coix seed and mung bean as the raw materials for preparing the high-content coarse cereal noodles. The optimal dietary fiber content, particle size distribution, damaged starch, water solubility and cooking loss conditions are obtained through research, and the quality of the noodles is guaranteed.

The invention carries out superfine grinding, spray drying, extrusion puffing and microwave pretreatment on the coarse cereal powder, and the prepared noodles have relatively high taste quality and relatively excellent appearance state, toughness, mouth-feel and smoothness.

Through testing and groping the freezing process, the noodles have good sensory qualities such as appearance, palatability, toughness, refreshing property and the like under the low-temperature freezing condition of the invention.

Drawings

FIG. 1 is a graph showing the effect of the millet-coix seed mixing ratio on noodle cooking loss rate and sensory score.

FIG. 2 is a graph showing the influence of the millet-coix seed-mung bean mixed powder ratio on the noodle cooking loss rate and sensory score.

FIG. 3 is a graph showing the effect of water addition on the loss rate of noodle cooking.

FIG. 4 is a graph showing the effect of water temperature on the loss rate of noodle cooking.

FIG. 5 is a graph showing the effect of proofing time on the loss rate of cooked noodles.

FIG. 6 is a graph of the response of the amount of water added and the temperature of the water to the loss rate of the noodles cooking.

FIG. 7 is a graph of the response of water temperature and proofing time to noodle cook loss rate.

FIG. 8 is a graph of the effect of different pretreatment techniques on the in vitro digestion characteristics of noodles.

Fig. 9 shows the influence of different pre-treatments of the coarse cereal flour on the microstructure of the noodles, which are 1-common 2-superfine grinding 3-microwave 4-spray drying 5-extrusion puffing from left to right.

FIG. 10 shows the effect of freezing temperature on the microstructure of the noodle at (1) -25 ℃, (2) -30 ℃, (3) -35 ℃, (4) -40 ℃, (5) -45 ℃ from left to right.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Unless otherwise specified, all technical means used in the specification are technical means known in the art. All the raw materials are commercially available.

Test example 1

Removing impurities from semen Setariae, Coicis semen, semen Avenae Nudae, semen Fagopyri Esculenti, herba Avenae Fatuae, semen Phaseoli Radiati and semen Sojae Atricolor, cleaning, and air drying. Grinding the eight kinds of coarse cereals respectively with a mill, sieving with a 80-mesh standard sieve, and packaging in a sealed bag at-4 deg.C.

The detection content and the detection method are as follows:

moisture content: refer to national standard GB 5009.3-2016.

Ash content: refer to national standard GB 5009.4-2016.

Protein: refer to national standard GB 5009.5-2016.

Fat: refer to national standard GB 5009.6-2016.

Total dietary fiber: refer to national standard GB 5009.88-2014.

Starch: refer to national standard GB 5009.9-2016.

Damaged starch: refer to the national standard GB/T9826.88-2008.

Amylose starch: refer to the national standard GB/T15683-2008.

When the content of damaged starch in the coarse cereal flour is high, the water absorption rate of the dough can be obviously increased, so that the prepared noodles are softer, the cooking loss is more, and the quality is poorer. Among the five cereal flours, oat has the highest damaged starch content of 6.56%, probably because oat grains are harder and starch damage is severe. Among the three beans, the broken starch content of mung bean is the highest and is 6.45%. The content of damaged starch of the coix seeds is the least, 1.64 percent, which is obviously lower than that of other coarse cereal powders.

In the five cereals, the particle size of the coix seed powder is larger than that of the other four cereals in various distributions, and the particle size distribution range is also larger, which indicates that the coix seed powder is uneven in quality and coarse. The small particle size distribution range of the oat flour indicates that the oat flour is fine and smooth in flour quality, but the content of damaged starch is relatively high. Among the three bean powders, the particle size of the black bean powder is obviously different from that of red bean and mung bean and is larger than that of the other two bean powders, which indicates that the black bean powder is uneven in powder quality and relatively coarse.

Detecting the contents of fast-digestion starch (RDS), slow-digestion starch (SDS) and Resistant Starch (RS) of different coarse cereal powders, and finding that the RDS contents of different coarse cereal powders are obviously different, wherein the RDS content of the black beans is far higher than that of other coarse cereals, and the black beans show high digestion characteristics; the five cereals have highest RDS content of 25.19% of oat and highland barley. The highest SDS content is buckwheat, and the lowest is mung bean. The RS content of the coix seed is obviously higher than that of other coarse cereals, and the buckwheat is used as the second ingredient.

The total content of amino acids in the coarse cereal powder is 7.09-34.35 g/100 g. The black bean has the highest total amino acid content, the mung bean and the highland barley.

The analysis of the basic components, the particle size distribution condition, the hydration characteristic, the digestion characteristic and the protein nutritive value of the eight coarse cereals shows that the content of dietary fiber of the millet and the highland barley is higher than that of other grains, the particle size distribution range of the highland barley powder is larger, the powder quality is coarser, and the content of damaged starch is less. The oat flour has small particle size, fine flour and high damaged starch content. The water solubility of the black beans is high, which indicates that the steaming loss of the black bean flour product is high, and the quality of the noodles is influenced. After comprehensive consideration, millet, coix seed and mung bean are selected as the raw materials for making the high-content coarse cereal noodles.

Example 1:

the experiment takes millet, coix seed, mung bean and wheat flour as raw materials, wherein the proportion of the wheat flour is 20%, the proportion of the coarse cereal flour is 80%, the proportion of the millet, coix seed and mung bean is adjusted, the water adding amount, the water temperature and the proofing time are used as single factors, the cooking loss rate is used as an evaluation index, and the manufacturing process parameters of the coarse cereal noodles are optimized through a response surface experiment so as to manufacture the high-content coarse cereal noodles with low loss rate and good taste.

Compounding coarse cereal noodle flour: the total amount of the flour is 100 percent, the proportion of the fixed wheat flour is 20 percent, and the mixed coarse cereal powder of millet, coix seed and mung bean is 80 percent. The dough kneading process parameters are fixed as 50% of water addition, 50% of water temperature and 10min of fermentation time, the noodle is made by using an extrusion noodle machine, and sensory evaluation value and cooking loss rate are used as evaluation indexes. Firstly, millet flour and pearl barley flour are compounded according to the proportion of 7: 1, 6: 2, 5: 3, 4: 4, 3: 5, 2: 6 and 1: 7, and millet-pearl barley mixed powder with the optimal proportion is selected and then compounded with mung bean powder, so that the proportion of the millet-pearl barley-mung bean mixed powder is determined.

The product detection content comprises cooking loss rate determination and sensory evaluation method (with reference to the method in SB/T10137-93)

The noodle processing technological condition parameters are as follows: according to the compound result of the coarse cereal powder, taking wheat, millet, coix seed and mung bean as raw materials in a ratio of 2: 1.5: 2.5: 4, under the condition that the stirring time is fixed for 5min, taking the cooking loss rate as an evaluation index, and carrying out single-factor experiments on three condition parameters of water addition amount, water temperature and fermentation time.

Adding water: the fixed water temperature is 50 ℃, the fermentation time is 10min, and the water addition gradient is as follows: 35%, 38%, 41%, 44% and 47%.

Water temperature: the fixed water adding amount is 41%, the fermentation time is 10min, and the water temperature gradient is as follows: 30 deg.C, 40 deg.C, 50 deg.C, 60 deg.C, 70 deg.C.

And (3) fermentation time: the fixed water adding amount is 41 percent, the water temperature is 50 ℃, and the fermentation time gradient is respectively as follows: 0min, 5min, 10min, 15min, 20 min.

Response surface experimental analysis optimization: and (3) designing a response surface analysis experiment by taking the water adding amount, the water temperature and the fermentation time as single factors and the cooking loss rate as an evaluation index, and optimizing and determining the optimal process condition parameters through the response surface experiment.

Compounding coarse cereal noodle flour: the influence of the addition of the coix seeds on the sensory score and the cooking loss rate of the coarse cereal noodles is shown in figure 1, and the graph shows that the cooking loss rate of the noodles tends to decrease first and then increase along with the increase of the content of the coix seeds, probably because the dough of the coix seeds has stronger water absorption capacity, the addition of a proper amount of the coix seeds can improve the property of the dough of mixed flour, increase the elasticity of the dough and reduce the cooking loss rate of the noodles, but because the content of dietary fibers of the coix seeds is higher and the water absorption rate is higher, the surfaces of the noodles are rougher and rougher along with the increase of the content of the coix seeds, dissolved substances during cooking are more and more, the mouthfeel is not fine and smooth, the sensory score is reduced, so the measurement experiment of the addition of the mung beans is carried out on the basis of the proportion of millet to coix seeds of 3: 5.

As can be seen from fig. 2, the cooking loss of the noodles is reduced after the mung bean powder is added, because the addition of mung bean improves the kneading resistance of dough, improves the structure of the minor cereal noodles, the cooking loss rate is lowest when the ratio of the mixed millet-coix seed powder to the mung bean powder is 4: 4, and when the ratio of the mung bean powder exceeds 1/2(4/8), the noodles are dark in color, have the dark green color of mung bean, are harder in taste, have stronger and stronger beany flavor, and affect the sensory quality of the noodles, so the ratio of the mixed millet-coix seed powder to the mung bean powder is 4: 4, namely the ratio of the millet to the coix seed to the mung bean in the minor cereal powder is 1.5: 2.5: 4, and the ratio of the formula powder of the minor cereal noodles is 2: 1.5: 2.5: 4.

Embodiment 2 optimization of the production process of the coarse cereal noodles

The influence of the water adding amount on the noodle cooking loss rate is shown in fig. 3, as shown in the figure, when the water adding amount is less than 41%, the cooking loss rate of the noodle is gradually reduced, because the water adding amount is more and more close to the water absorption capacity of mixed flour, the gluten is fully absorbed and expanded to form a gluten network, meanwhile, the starch is also absorbed and expanded, and the starch is wrapped in the gluten network, so that the elasticity of the noodle is increased, the hardness of the noodle is improved, the cooking time of the noodle is shortened, and the cooking loss rate is reduced. When the water addition amount exceeds 41%, the water addition amount exceeds proper water, the viscosity of the dough is dominant in the dough, the stretching resistance of the noodles is reduced, the surfaces of the fresh and wet noodles are sticky, and the loss after cooking is large, so the water addition amount in subsequent response surface experiments is selected to be three levels of 38%, 41% and 44%.

The influence of the water temperature on the cooking loss rate of the coarse cereal noodles is shown in fig. 4, and the cooking loss rate of the noodles tends to decrease first and then increase along with the increase of the water temperature. Before 50 ℃, gluten structure is gradually formed along with the rising of water temperature, the function between protein and starch is more and more obvious, the extruded noodles become elastic, and the cooking loss rate is reduced. When the water temperature continuously rises, the protein is deteriorated, the interaction with the starch is weakened, and the gluten structure is gradually solidified and hardened, so that the cooking loss rate is increased. Three levels of water temperature factors were selected of 40, 50, 60 ℃.

As shown in fig. 5, in the dough making process, if direct extrusion without proofing is performed, the cooking loss rate of the noodles is high and exceeds 6%, and the cooking loss rate of the coarse cereal noodles after proofing tends to decrease first and then increase with the prolongation of proofing time, mainly because proofing can promote the migration of moisture, so that the moisture is in contact with protein colloid particles, and the protein colloid particles are hydrated through hydrogen bonds, so that the formation of a gluten structure is promoted, but the proofing time is prolonged, the internal structure of dough is changed, the moisture is dissipated to the surface of the dough, the noodles are sticky, and the cooking loss rate is increased. Three levels of 5, 10, 15min were chosen as the time to wake up factor in subsequent response surface experiments.

Response surface experimental analysis: the data are analyzed and sorted according to the analysis result table of variance, and a regression equation of the cooking loss rate can be obtained as follows:

Y＝6.03+0.19A-0.17B-0.44C-0.035AB+0.15AC-0.018BC+0.61A²+0.34B²+0.31C²

p value of regression model<0.0001, extremely remarkable, model mismatching term P value of 0.3517>0.05, not significant, indicating that the model fit is good. In the model, A, B, C, AC and A have significant influence on the cooking loss rate of noodles²、B²、C²Influence ranking as wake-up time>Amount of added water>Water temperature, model signal-to-noise ratio of 22.750>4, the model can be used for analyzing and predicting the cooking loss rate of the noodles.

The influence of interaction of various factors on the cooking loss rate is shown in figure 6, when the fermentation time is fixed, the interaction between the water adding amount and the water temperature is strong, and the cooking loss rate is firstly reduced and then increased along with the increase of the water adding amount and the water temperature; in the interaction between the water adding amount and the proofing time, the proofing time has larger influence on the cooking loss rate, and the slope is steeper relative to the water adding amount; in fig. 7, the response surface plot slopes more gradually, illustrating that the interaction of water temperature and proofing time has less effect on the noodle cooking loss rate.

According to Design Expert, the best conditions of the manufacturing process are as follows: adding water 40.335%, water temperature 57.340 deg.C, and fermenting for 12.493min, wherein the cooking loss rate is 5.918%. Considering the experimental operability, the conditions were adjusted to 40% water addition, 57% water temperature, and 12.5min proving time, and the experimental results were carried out to obtain a cooking loss rate of (5.919 ± 0.05)%, which substantially coincides with the theoretical value.

In the embodiment, a single-factor experiment is firstly carried out, and on the basis, a response surface experiment is utilized to carry out analysis and optimization, so that the optimal process condition parameters for preparing the coarse cereal noodles are that the water adding amount is 40%, the water temperature is 57 ℃, and the fermentation time is 12.5min, and under the conditions, the cooking loss rate of the noodles is (5.919 +/-0.05)%.

Example 3 pretreatment test for coarse cereal flour

The experiment adopts five different modes of unprocessed, superfine grinding, microwave, extrusion puffing and spray drying to process the coarse cereal flour, noodles are prepared according to the proportion of wheat to millet to coix seed to mung bean of 2 to 1.5 to 2.5 to 4, indexes such as chromatic aberration analysis, in-vitro digestion characteristics, texture characteristics of the noodles, cooking quality, microstructure analysis and sensory evaluation are combined, and the adaptability of different pretreatment modes to the improvement of the preparation of high-content noodle products by the coarse cereal flour and the influence of different treatments on the quality of the coarse cereal noodles are explored.

The specific process of pretreatment is as follows:

(1) preparation of coarse cereal raw powder

The coarse cereal raw materials are crushed by a crusher and sieved by a standard sieve of 80 meshes to obtain raw powder.

(2) Preparation of superfine pulverized powder

The raw powder is placed in a raw material cavity of a ball mill and is processed at the rotating speed of 380r/min, the ball-material ratio of 4: 1 and the time of 120 min.

(3) Preparation of microwave powder

The raw powder is placed in a culture dish or a special microwave lunch box, and intermittently heated for 3min (60 s/time) by middle and high fire at 700W and 2450 MHz.

(4) Preparation of extruded puffed powder

Measuring the water content of the mixed coarse cereal raw powder in proportion → adjusting the water content to 18% → preheating of an extruder → extrusion → crushing

Determining the water content of the mixed coarse cereal raw powder: the method of GB/T21305-2007 is adopted for measurement.

Adjusting the moisture content: setting the water content of the mixed powder in the mixer to be 18%, fully mixing the water and the raw powder after calculating the required water addition amount, and mixing for 10-15min by using a mixer.

Preheating an extruder: the temperatures of the four zones are respectively: the temperature in zone I is 60 ℃, the temperature in zone II is 90 ℃, the temperature in zone III is 120 ℃, and the temperature in zone IV is 150 ℃.

Extruding: the screw speed was 280 r/min.

(5) Preparation of spray-dried powder

The coarse cereal powder is prepared into a solution with the feed liquid concentration of about 5 percent, and the solution is stirred overnight by a magnetic stirrer. The well stirred solution was passed through a colloid mill and filtered using a 100 mesh standard sieve. The spray dryer is started and preheated to the desired temperature. Spray drying is carried out according to the air inlet temperature of 140 ℃, the air speed of the circular air blower of 80 percent and the sample loading amount of the solution pump of 30 percent.

And (3) color difference analysis: as can be seen from table 1, the Δ L value of the noodle prepared by spray-drying the coarse cereal flour is the smallest, indicating that the whole color of the dough sheet is darker. The color of the noodle becomes dark obviously after the spray drying treatment. In a whole view, the noodles subjected to superfine grinding treatment are brighter in color and luster, and the whole chromaticity of the noodles is yellowish brown due to spray drying and extrusion puffing treatment, so that the color of the noodles is too dark due to the adoption of the powder subjected to spray drying and extrusion puffing treatment when the high-content coarse cereal noodles are prepared.

TABLE 1 influence of different pre-treatments of coarse cereal flour on color difference of noodles

Note: the values shown in the table are mean ± standard deviation, no significant difference between values with the same letter in the same column (P >0.05), significant difference between values with different letters in the same column (P < 0.05).

In-vitro digestion characteristics of the noodles: as can be seen from fig. 8, in the whole in vitro digestion simulation process of the noodles prepared by the five different pretreatment technologies, the digestibility of each sample of the minor cereal noodles shows a trend of increasing continuously with the increase of the digestion time. The starch hydrolysis rate is rapidly increased within 0-60 min; gradually becomes gentle at 60-180 min. During the digestion process, the hydrolysis curves of the five noodles have approximately the same trend and have no obvious difference with each other. It follows that different pretreatments of the cereal flour do not lead to large differences in starch digestibility.

Quality and structure characteristics of the noodles: as can be seen from table 2, there was no significant difference in the sample heights of the noodles, indicating that the noodles were uniform in quality. The noodle prepared from the extruded and puffed flour has lower hardness and crispness than other four kinds of noodles, but has higher viscosity. A moderate increase in viscosity does not affect the final quality of the noodles, but too high viscosity may cause a decrease in organoleptic properties such as stickiness and poor taste. The superfine crushed coarse cereal powder is superior to other treatments in cohesiveness and recoverability after being prepared into noodles, because the superfine powder has small particle size and uniform distribution, the characteristics are favorable for forming a compact network structure of dough, the particle size is small, the content of damaged starch is high, the bonding effect is enhanced, the combination degree of components such as fiber, starch and protein is enhanced, and the gluten structure is uniform and compact, so that the noodles are greatly improved in cohesiveness, elasticity, adhesiveness, chewiness, recoverability and the like, and the processing adaptability of the coarse cereal raw materials is improved to a certain degree.

TABLE 2 Effect of different pretreatment techniques on texture Properties of noodles

The optimal cooking time is mainly determined by the difficulty of gelatinization of starch in the noodles and the water absorption rate of the noodles. As can be seen from table 3, the best cooking time of the microwave-treated noodles is the longest, which requires 3 minutes, and the extruded and puffed noodles are the shortest, mainly because the starch granules are gelatinized to a certain degree in the extrusion and puffing process, the state that the white hard core disappears is easily achieved in the cooking process, and the best cooking time is shortened. Superfine pulverizing noodles. The cooking loss rate of the noodles and the turbidity of the noodle soup are in positive correlation. As can be seen from table 3, the noodle prepared by the extrusion-puffed powder had a high boiling loss rate, a high breakage rate, and a high turbidity of the noodle soup, and the noodle subjected to the spray drying had a low boiling loss.

TABLE 3 Effect of different pretreatment techniques on the cooking characteristics of noodles

And (4) microstructure analysis, namely representing the microstructure of the noodles made of the pretreated coarse cereal powder. As can be seen from FIG. 9, the ultrafine-milled noodles had a poor network structure, less intact starch granules and more pores. Except for the superfine grinding, the frozen and cooked noodles of other 4 kinds of noodles have relatively good quality, and most of the starch is connected into a sheet shape and embedded in a continuous and compact gluten network.

Protein secondary structure: the amide I band (1600-1700cm-1 fragment pattern) was analyzed using Peakfit v4.12 software. Performing baseline correction and Gaussian deconvolution on the map, fitting a second derivative to obtain a characteristic peak, performing curve fitting by taking the position of the characteristic peak as a parameter to calculate the peak area, and determining the content of the secondary structure of the protein. The content of each secondary structure of the protein is calculated by measuring with a Fourier infrared spectrometer and is shown in the following table. From table 4, the noodle prepared by different pretreatment methods has no significant difference in each component in the protein secondary structure, which indicates that the spatial conformation formed by the protein polypeptide chain in the coarse cereal noodle is not affected by the pretreatment technology of the flour.

TABLE 4 influence of different pretreatment techniques on the secondary structure of protein in coarse cereal noodles

Sensory evaluation: referring to table 5, when the coarse cereal flour is added in the same proportion, the noodles prepared by superfine grinding, spray drying, extrusion puffing and microwave treatment are relatively high in taste and quality. The noodle that the spray drying mode was handled is relatively better in apparent state, toughness, tasty and refreshing nature and lubrication degree, this is because spray drying's powder particle diameter is less, and the degree of consistency is higher, and under the effect of air current, only less granule can pass through cyclone smoothly and enter into the link that the product was collected, has guaranteed the smoothness nature of noodle to a certain extent.

TABLE 5 Effect of different pretreatment techniques on sensory score of noodles

According to the experiment, the quality analysis and the functional characteristic evaluation are carried out on the noodles prepared by the pretreatment technologies of five coarse cereal powders, namely untreated, superfine grinding treatment, spray drying treatment, extrusion puffing treatment and microwave treatment, so that the pretreatment technology has small influence on the nutritional ingredients and the functional characteristics of the coarse cereal noodles, and has relatively obvious influence on the quality (such as chromaticity, texture, cooking characteristics and sensory evaluation) of the noodles. The superfine grinding treatment can make the noodles brighter in color, and the spray drying and extrusion puffing treatment can make the integral chroma of the noodles yellowish brown. For texture characteristics, the noodles made of the extruded and puffed powder are lower in hardness and brittleness than other four treatments, but have higher viscosity; the superfine crushed coarse cereal powder is superior to other treatments in cohesiveness and recoverability after being made into noodles. The best cooking time of the microwave-treated noodles is longest, 3 minutes is needed, the extruded and puffed noodles are shortest, but the cooking loss rate, the noodle breakage rate and the noodle soup turbidity degree of the noodles made of the extruded and puffed powder are higher; the noodles subjected to spray drying treatment have low cooking loss and small turbidity of the noodle soup, and the cooking quality of the noodles is improved to a certain extent. The superfine crushed noodles have poor network structure, are easy to dissolve out when being cooked and gelatinized, and have relatively high cooking loss rate. According to sensory evaluation, the noodles prepared by carrying out superfine grinding, spray drying, extrusion puffing and microwave treatment on the flour have relatively high taste quality. The noodles treated by the spray drying method are also relatively excellent in appearance, toughness, refreshing property and smoothness.

Example 4 preparation of frozen cooked noodles

The experiment mainly researches the influence of the freezing temperature (-25 ℃, 30 ℃, 35 ℃, 40 ℃ and 45 ℃) of the cooked coarse cereal noodles on the quality characteristics of the frozen cooked noodles, including four aspects of texture characteristics, cooking quality, microstructure and sensory quality, and researches the change of the microstructure in the noodles by adopting a Scanning Electron Microscope (SEM) so as to supplement the influence of the quick freezing temperature in the freezing stage on the quality of the frozen cooked noodles after the fresh and wet noodles are cooked.

The preparation process of the frozen cooked noodles comprises the following steps:

mixed powder → flour-mixing → constant temperature and humidity fermentation → extrusion → boiled flour → shower cooling → quick freezing for 30min (for analyzing the properties of the obtained frozen and boiled flour, freezing storage and reheating are carried out subsequently) → 18 deg.C freezing storage for 24h → reheating for 90s

The temperature of quick freezing is set at five levels of-25 deg.C, -30 deg.C, -35 deg.C, -40 deg.C and-45 deg.C.

And (4) analyzing the texture characteristics, wherein the heights of the frozen and cooked noodle samples have no significant difference, and the quality of the noodle samples is uniform. As the freezing temperature was decreased, the freezing speed was increased, and the hardness, stickiness, chewiness and elasticity of the noodles were the greatest at-40 c and the worst at-25 c, indicating that low temperature freezing might be more conducive to the preservation of texture properties of the cooked noodles during freezing. Under the low-temperature freezing condition, the time for the core temperature of the noodles to be reduced to the freezing temperature is obviously shortened, namely the time for the zone passing through the maximum ice crystal formation is shortened, the mechanical damage caused by the growth of the ice crystals is reduced, and the protein structure is kept more intact.

And (3) microstructure analysis: it can be seen from the microstructure diagram 10 that when the quick-freezing temperature is higher (-25 ℃), the network structure is poor, the discontinuity phenomenon is relatively serious, the network structure is seriously torn into fragments, the holes are relatively large, the distribution is uneven, and the edge is rough. The sample quick-frozen at the temperature of minus 40 ℃ has the advantages that the damage of the network structure is not obvious and is relatively continuous and complete, the holes are relatively small and dense, the number is obviously increased, and the torn part still appears.

And (3) analyzing cooking characteristics: the effect of freezing conditions on the cooking characteristics of frozen cooked noodles is shown in the following table. As can be seen from the table, the higher the freezing temperature, the higher the boiling loss rate, the breakage rate and the turbidity of the noodle soup of the noodles after reheating, and the boiling loss rate of the frozen product at-25 ℃ is significantly higher than-40 ℃. Under the freezing condition of-40 ℃, the freezing speed is higher, and the time for the central temperature of the product to fall to the freezing point is also relatively faster. Further, the lower the freezing temperature, the lower the water absorption of the noodles, indicating that the noodles frozen quickly at the lower freezing temperature have less water absorption during rehydration.

TABLE 6 Effect of freezing temperature on steaming characteristics of noodles

Sensory evaluation: sensory evaluation was performed on the rehydrated frozen cooked noodles, and the results are shown in table 7 below. The following table and the above experimental results show that the noodles have good organoleptic qualities such as appearance, palatability, toughness and refreshing property under the low-temperature freezing condition. The reason is that the network structure inside the noodles is well protected by the low temperature freezing, which also indicates that the organoleptic quality and freezing stability of the frozen cooked noodles are closely related to the internal structure and components of the noodles.

TABLE 7 Effect of freezing temperature on sensory evaluation of noodles

In the process of freezing cooked noodles, different freezing temperatures result in different freezing rates of the noodles. The lower the freezing temperature, the faster the noodle freezing rate, the shorter the freezing time and the time for forming a band through the largest ice crystal, and the good texture characteristics, cooking quality and sensory evaluation after rehydration of the frozen and cooked noodle. The quality of the cooked noodles is better under the condition of minus 40 ℃ by comprehensively considering the product quality and the processing cost. Under the condition of higher freezing temperature, the internal network structure of the noodles is obviously destroyed after the frozen cooked noodles are reheated, and the cooking loss rate is higher.

Example 5

A kind of noodles is made up of wheat flour and grains flour (2: 1.5: 2.5: 4).

1) grinding: grinding the coarse cereals into powder respectively, and sieving the powder through a sieve of 50 meshes to 140 meshes to obtain coarse cereal powder; pretreating the coarse cereal powder by spray drying (the method is the same as the example 3);

2) kneading: mixing coarse cereal flour and wheat flour to obtain dough, wherein the mixing process parameters comprise water addition amount of 40%, water temperature of 57 ℃, and proofing time of 12.5 min;

3) making noodles: making the kneaded dough into noodles;

4) boiling the noodles → pouring and cooling for → -40 deg.C, quick-freezing for 30min → -18 deg.C, and freezing for storage.

In the steps after frozen storage, including logistics, selling, storage, etc., it is sufficient at-18 ℃ or-20 ℃.

Although the present invention has been described in the foregoing by way of examples, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

1. The minor cereal noodles are made of flour, and are characterized in that the flour comprises 18-22 parts by mass of wheat flour and 78-85 parts by mass of minor cereal powder, and the minor cereal powder comprises powder of millet, coix seeds and mung beans.

2. The coarse cereal noodles as claimed in claim 1, wherein the mass ratio of the millet to the coix seed to the mung bean is 1-2: 2-3: 4.

3. The coarse cereal noodles as claimed in claim 1, wherein the flour of the coarse cereal noodles is prepared from wheat, millet, coix seed and mung bean in a mass ratio of (1.8-2.2) to (1.4-1.6): (2.4-2.6) to 4.

4. A method for producing the minor cereal noodles according to any one of claims 1 to 3, characterized by comprising the steps of:

2) kneading: mixing coarse cereal flour and wheat flour into dough, wherein the technological parameters of the dough mixing are 35-50% of water addition, 30-70 ℃ of water and 0-20 min of proofing time;

3) making noodles: and preparing the kneaded dough into noodles.

5. The method for making the minor cereal noodles according to claim 4, wherein the process parameters of dough kneading are as follows: adding water in an amount of 40-42%, heating water at 55-59 ℃, and fermenting for 11-15 min.

6. The method for producing cereal noodles according to claim 4, wherein the cereal flour obtained by milling is subjected to a pretreatment which is one or more of micronization, microwave treatment, extrusion puffing and spray drying;

the microwave treatment comprises the following steps: intermittently heating the coarse cereal powder obtained by milling for 2-5 min at 700W and 2000-3000 MHz;

the spray drying comprises the following steps: and preparing the coarse cereal powder obtained by milling into a solution with the concentration of feed liquid of 2-10%, and carrying out spray drying at the temperature of an air inlet of 120-160 ℃.

7. The method for making coarse cereal noodles according to claim 6, wherein the microwave treatment comprises: intermittently heating the coarse cereal powder at 700W and 2450MHz with medium and high fire for 3min for 60s each time.

8. The preparation method of the coarse cereal noodles according to claim 6, wherein the pretreatment is spray drying, coarse cereal powder is prepared into a solution with a feed liquid concentration of 4-6%, the solution is uniformly stirred, then is subjected to a colloid mill, and is filtered by a standard sieve of 80-120 meshes; and carrying out spray drying at the temperature of an air inlet of 130-150 ℃.

9. The method for producing miscellaneous grain noodles according to any one of claims 4 to 8, wherein the produced miscellaneous grain noodles are quick-frozen after cooking at a freezing temperature of-25 ℃ to-45 ℃ to obtain frozen cooked noodles.

10. The preparation method of the minor cereal noodles as claimed in claim 9, wherein the prepared minor cereal noodles are subjected to noodle boiling, showering cooling and quick freezing for 25-40 min, wherein the temperature of the quick freezing is-38 ℃ to-42 ℃.