CN1044671C - Production method of extruded fried cereal food - Google Patents

Abstract

The present invention provides an improved production method for extrusive high-quality fried grain food, wherein grain dough containing protein is extruded, the extruded grain dough is dried, and then, the fried grain food having the advantages of low gelatine or tooth sticking property and coarse sand texture is obtained.

Description

Production method of extruded fried cereal food

The present invention relates to a process for the production of extruded fried cereals.

As described by Matz, Snack Food Technology, common corn flake processing methods start with corn flour or corn paste. Molar white and yellow corn were added to vats containing hot water and proportional amounts of lime. Heat the mixture to boiling point and let the food sit for 10-20 hours after turning off the heat. During this time, the corn hulls are hydrated and partially hydrolyzed. The corn husk softens to a jelly-like consistency and is easy to remove later in the process. Starches are also gelatinized. At the end of this steeping time, the corn kernels had absorbed about 50 wt% (weight %) of water. Peel in a water jet in the washing machine while removing any remaining lime. The washed corn kernels are then transferred to a stone mill and ground into balls or paste. The masa is formed (usually by hand) into large cylindrical slivers which are then fed into a hydraulic extruder. The barrel chamber of the extruder houses a tight-fitting piston that forces the corn dough through a die plate provided with a series of slots. The cutting unit cuts the extruded corn into pieces. Corn dough, on the other hand, can be rolled into thin strips and then cut into shapes. Corn dough slices are dropped directly into the heated cooking oil. After the moisture content of the corn dough slices has dropped to about a few percent, the resulting cooked corn product is salted and cooled and packaged.

This common method of producing cornflakes has a number of disadvantages, including that the cornflakes have a gritty texture and tend to stick to the teeth.

One of the methods of eliminating these drawbacks is described in commonly assigned US 4645679, which proposes comminuting a hydrated starch material, such as potato starch, with hydrated corn to produce cornflakes.

Accordingly, it is an object of the present invention to provide a process for the production of extruded and fried cereal products having an expanded delaminated structure that allows for the formation of tortilla shapes and enhances the texture of corn chip products.

Therefore, according to the present invention there is proposed an improved process for the production of extruded and fried cereals comprising the steps of:

Feed the grain flour and water into the extruder along with the protein source;

Extrude this mixture into a dough;

pressing the dough into a strip and cutting the strip into slices of desired shape; and

These slices are fried into food.

In the present invention, corn is used for illustration. Of course, the invention is readily applicable to a variety of other grains such as wheat, rice, barley and barley, as described below. The scope and concept of the present invention are not limited to the use of corn. Examples of corn kernels include kernels formed from yellow corn and white corn. Mixtures of these raw material particles can also advantageously be used.

The present invention can be made into corn flakes (corn flour tortillas), which can be described as meringue cakes, which have high lubricity, fast melting in the mouth and low hardness. These products have a characteristic corn flavor of medium intensity.

Tortillas are generally considered to be obtained from a dough made of cornmeal, water, salt, and oil, which is pressed into strips and cut into common tortilla shapes and sizes. In contrast to the present invention, these products are usually baked and optionally additionally fried to a desired end product. However, direct frying of the dough having the composition described in the present invention without a baking step produces a product having a tortilla-like structure which is very satisfactory, as explained in detail below.

Qualified corn or grain flour may be made by any method, such as milling, that produces a satisfactory comminuted product. From a texture standpoint, it is particularly advantageous to grind the corn with a shredder such as the Urschel Comitrol manufactured by Urschel Laboratories, Inc., Valparaiso, Indiana (see US 3728311). This patent describes the use of such a shredder in the corn crushing process.

The cereals used in the practice of the present invention consist essentially of cereal meal or flour which has not been precooked or pregelatinized and which may contain up to about 40% by weight (on a dry basis) of partially precooked or pregelatinized of grains. By "partially gelatinized" is meant that the grain is roughly 70-80% gelatinized.

According to the present invention, protein is combined with dough to make protein-containing dough.

Examples of protein sources include (but are not limited to) soy protein concentrates and isolates, pea protein, corn protein (zein), rice protein, or dairy proteins (such as lactalbumin, casein, whey solids, and skim milk powder) and mixtures thereof.

These protein sources are generally available in amounts of about 4.5-25 wt% (dry weight basis).

In the above mixtures, the cereal flour is generally present in an amount of 70-95% by weight (on a dry basis).

When protein sources are added to corn flour or grain mixtures, protein-starch interactions are strengthened and viscosity increases. This results in more mechanical energy being transferred (friction) to the extruder. As the protein undergoes structural changes, its ability to hold water increases, creating dry zones. Also, as the amount of water in the extruder increases, the starch hydrates to a greater extent, which increases starch viscosity and cooking processing. Adding additional water did not reduce friction in the extruder (which generates heat); instead, it increased friction due to protein-protein and protein-starch interactions. The result of these interactions is a change in the rheology of the dough, resulting in a dough that retains more water during pressing and has greater strength and elasticity.

During frying, as the heating progresses, the high water content (approximately 35%) separates and expands the soft press-dough disc, causing the formation of air bubbles larger in volume than would be obtained in the absence of protein (similar to tortilla chips expand). This expansive texture isn't just a superficial phenomenon. In fact, this expanded structure is due to the dough's ability to enclose air, thus possibly containing the steam generated by processing. The surface of the slice is as dense as a tortilla chip, but the slice is more crunchy and has a delaminated structure.

After the dough is made by extrusion process, the auxiliary input work operation is performed to improve the hydration and gelatinization effect of the corn, thereby reducing the gritty texture of the finished corn flakes and improving the adhesiveness of the dough.

This auxiliary work input operation can be accomplished by extruding the dough through an extruder. The extrusion step is carried out at a temperature of about 190-360°F (barrel temperature) for about 1-4 minutes (dwell time).

This extrusion can be performed using any conventional culinary processing extruder, although a twin-screw extruder is preferred of course.

The extrusion temperature is a function of the extruder barrel temperature and the amount of work input to the dough. The extrusion operation performs mechanical and compression work on the dough.

Form strips of extruded dough with a thickness of 0.25-0.60 inches. Although the dough may be rolled in any manner, satisfactory results have been obtained with multi-stage conventional two-roll mills. The pinch rolls include front and rear rolls that rotate about substantially parallel longitudinal axes. The diameter of the rear roller is slightly larger than the front diameter of the front roller.

Thus, dough roll strips having a thickness of about 0.020-0.040 inches can be made. Although the thickness of the tape produced is not critical, avoid producing tapes that are too thick as to adversely affect the melt-in-the-mouth properties of the product.

After the dough is rolled into a strip, the strip is used to form a sheet or loaf. Sheets or loaves are usually made by cutting the dough roll strip into pieces of the desired shape and size. For example, rectangular or triangular pieces with the most common corn flakes available commercially, oval or circular segments of tortillas can be made.

The pieces thus produced are then fried with usual means. Any kind of frying oil such as vegetable oil or tallow can be used. Oils or fats can be hydrogenated. Suitable oils include corn oil, soybean oil, palm oil, sunflower oil and mixtures thereof. Suitable tallows include lard and tallow. Seafood fats such as herring oil can also be used. The above-mentioned fats and oils are examples only, and do not limit the oils used in the present invention.

A preferred frying temperature is about 375-390°F.

The finished slices are crisp, delaminated, non-gritty and smooth. The fat content of the finished tablet is about 25-27 wt%, preferably about 25%.

Salt or other flavor enhancers or seasonings may be added to the finished cornflakes. The cornflakes preferably contain about 0.8-1.4 wt% salt, more preferably about 1.5 wt% salt. Other flavor enhancers and seasonings that may be used are salt substitutes such as potassium chloride, ammonium chloride, seasoning salts and herbal extracts. Cheese and synthetic cheese dressings are also available.

Example 1

Puff Popped White Corn Flakes

Make a finely dispersed flour with the following ingredients in a batch mixer for 15 minutes:

Composition %(D.B.)

Popped White Corn 86.04

Soy Protein Concentrate 12.26

Sodium carboxymethyl cellulose 1.5

Acetylated monoglycerides 0.2

The mixture was gravity transferred to a K-tube feeder which fed the mixture to the first extruder at a ratio of 4/1 dry solids to water. The dough is formed by mixing and inputting work over a period of approximately 45 seconds. The twin-screws rotate at 300rpm (rev/min) to move the product forward to the extruder die, which is connected to the shrink tube (creating negative pressure). Gradually increasing the pressure increases the mechanical energy at this stage of the process. At the end of the shrink tube is the inlet to the second extruder. From the exit of the extruder, a strand of material is extruded through a die and rolled to form a cohesive/non-sticky dough. Extrusion of ground corn containing protein and carboxymethyl cellulose yields an extrudate that forms a high strength and high elasticity dough that can withstand stretching during rolling into strips and forming operations. The protein changes the rheology of the extruded material due to increased torque and pressure in the extruder. Rolled strips are sliced and fried in corn oil. After the resulting finished slices are cooled, condiments are added to one side thereof. The fried chips have a pleasant corn flavor and have a light expanded delaminated structure with uniform porosity for a tortilla texture.

Doughs made from extruded corn without added carboxymethyl cellulose or protein tended to fall apart at high water levels of 25-30% during stripping and shaping. Corn flakes formed from this dough lacked the expanded delaminated structure observed when the protein and carboxymethylcellulose components were added.

Products made without the carboxymethylcellulose component were determined to be denser, drier and more gritty and sticky than products containing white matter and carboxymethylcellulose.

Example 2

According to the method of Example 1, the following mixture is used to make protein content high, namely the fried corn snack containing 18% protein in terms of total dry solids:

Composition %(D.B.)

Yellow corn 52.8

Partially cooked corn 17.0

Soy Protein Isolate 11.5

Soy Protein Concentrate 12.0

Sodium Carboxymethyl Cellulose 1.4

Lysine hydrochloride 0.03

Calcium Carbonate 2.0

Maltodextrin 3.0

Acetylated monoglycerides 0.2

Calcium carbonate is added as a fortified calcium source. It has been found that the ability of the dough to retain water is enhanced by the presence of protein. To press the dough into strips (the dough was found to be tough and dry) the water was increased by about 20%. It was also found that high protein content can increase the torque in the two extruders. Thus, adding protein can increase the degree of cooking by increasing the SME (mechanical energy per unit mass) in the first extruder. The finished flakes had a blistered delaminated structure similar to corn flakes. The product was also found to have a refreshing taste and improved texture as evidenced by increased crunchiness and shortening.

However, as in the case of fortified snacks, the addition of large amounts of protein to the mix can result in a product that spreads slowly during the mouth. The stickiness of the product was also improved. In this case, the effect of CMC (sodium carboxymethylcellulose) on tooth sticking and mouth melting is even more important.

Extrusion temperature and screw speed as well as frying conditions were the same as those used for the low protein content case.

Example 3

The extrusion system is a water-limited system. Although the protein improves the ability of the dough to retain water, there is still competition between the protein, starch, and gum for possible water. Colloids bind to proteins and allow starch to absorb water and swell. According to the extrusion method of Example 1 and the basic recipe of Example 2, a certain amount of pre-cooked yellow corn was used to partially replace the popcorn white corn to increase the hydration ratio, ensure swelling and thus improve the gelatinization of the dough.

The extrusion temperature in the last 5 zones of the cooker was reduced from 360°F to 220°F to reduce the possibility of overworking the dough. Over-processed dough creates a dense product, giving it a gummy texture. This is a result of starch (mainly amylopectin) degradation during extrusion. The amount of emulsifier was increased to twice the amount required to operate the 100% mixture of popped white corn. Only after carrying out these process steps can an elastic adhesive tape be obtained. Adding approximately 25% pre-cooked processed corn to the mix achieves essentially all-good results.

Another type of food was prepared by repeating the method of Example 1 with the following mixture:

Example 4

Nachos

Composition %(D.B.)

Molar yellow corn 89.7

Soy protein isolate 7.17

Sodium carboxymethyl cellulose 1.47

Acetylated monoglycerides 0.2

Sugar 1.44

Example 5

Protein and Calcium Fortified Corn Flakes

Composition %(D.B.)

Yellow corn 69.5

Soy Protein Concentrate 12.0

Soy Protein Isolate 12.0

Sodium carboxymethyl cellulose 1.4

Acetylated monoglycerides 0.1

Lysine hydrochloride 0.03

Calcium Carbonate 2.0

Maltodextrin 3.0

Example 6

Multi-grain flakes with a tortilla-like appearance

Composition %(D.B.)

Yellow corn 50.0

Rice flour 23.0

Wheat flour 18.8

Soy Protein Isolate 7.0

Sodium carboxymethyl cellulose 1.0

Acetylated monoglycerides 0.2

Example 7

Protein and calcium fortified multigrain flakes

Composition %(D.B.)

Yellow corn 46.0

Rice flour 20.0

Wheat flour 14.8

Casein 18.0

Sodium carboxymethyl cellulose 1.0

Acetylated monoglycerides 0.2

Example 8

Protein-fortified multigrain flakes

Composition %(D.B.)

Yellow corn 50.0

Rice flour 23.0

Wheat flour 18.8

Skim dry milk powder 7.0

Sodium carboxymethyl cellulose 1.0

Acetylated Monoglyceride 0.2

Example 9

Multi-ingredient flakes with a tortilla-like appearance

Composition %(D.B.)

Yellow corn 50.0

Rice flour 23.0

Wheat flour 18.8

Soy Protein Isolate 7.0

Sodium carboxymethyl cellulose 1.0

Acetylated monoglycerides 0.2

The fried products have been tested by a panel of sensory evaluation experts to determine eating quality, crunchiness and crispiness, etc. A panel of experts evaluated each of the products made in Examples 4-9 above. Each property was evaluated on a 9-point strength scale. For example, when evaluating crispness, a rating of 1 means that the product is "not brittle," while a rating of 9 means that the product is "extremely brittle." For mouth melting (quick to slow) and stickiness, a low value on the 9-point scale is desirable.

The grades assessed by the sensory evaluation expert panel for the products made in Examples 4-9 are in the following table I:

Table I

Comparative samples of pectin and protein effects in corn flake products WPC WPC+SPI WPC+SPC WPC+WPI/

SPC+CMC

Total protein ( %) 8 17.6 18 Soyin protein ( %) Sepathene 0 11 0 6 Concentrated object 0 0 16.5 8 carbuglymethyl cellulose sodium ( %) 0 0 0 1 maltose paste ( %) 0 0 2 2 2 2 2 2 2 2 2 2 2 Fat (%) 25 29 28 27

Sample characteristics of crispyness 5.4c 6.7B 6.8B 7.4A Ritter Crispy 5.8B 6.3AB 6.6A Portal Performing/Disposal 4.5B 5.2A 4.3B Adhesive Dental 5.0A 5.4A 4.4B Oil Narcotic Fate 3.7 3.5 3.6 3.4 Coarse sand texture 4.3 4.2 3.9 4.2 Oral adhesion 3.1 3.0 3.2 3.1 Overall taste 5.4 5.4 5.0 5.2 Non -special flavor 2.1 2.2 1.8 Note: WPC refers to the popcorn white corn

CMC refers to sodium carboxymethyl cellulose

SPI stands for Soy Protein Isolate

SPC means soy protein concentrate

a, b and c refer to the apparent degree of difference between products

After sampling and analysis, the panel concluded that products containing neither protein nor gum were denser, drier and exhibited a higher gritty texture and stickiness than products containing protein and gum Tooth level.

It has been found that protein-only products have a pleasant taste while giving them a flaky appearance. However, stickiness was evident, which is usually detected in extruded corn products. Products containing gum in addition to protein exhibit low stickiness without adversely affecting other properties.

It can also be seen from the above data that the addition of soy protein isolate, without the simultaneous addition of carboxymethyl cellulose, increases the crunchiness of the product while allowing the product to exhibit a taste similar to that of the control sample.

It can further be concluded from these examples that the addition of colloids increases the strength of the extruded strip and the water holding capacity which aids in achieving a delaminated texture, while also reducing stickiness. Improved ability to retain water also allows for high fat levels after frying. A high fat content of the fried product results in a high lubricating effect.

The following additional mixtures were prepared according to the method of Example 1 and tested by a panel of sensory evaluation experts, the conclusion data of which are listed in Table II below.

Example 10

Composition %(D.B.)

Popped White Corn 96.72

Sodium carboxymethyl cellulose 1.5

Sugar 1.5

Acetylated monoglycerides 0.2

B-carotene 0.08

Example 11

Composition % (by dry weight)

Popped White Corn 90.72

Soy Protein Concentrate 6.0

Sodium carboxymethyl cellulose 1.5

Sugar 1.5

Acetylated monoglycerides 0.2

B-carotene 0.08

Example 12

Composition %(D.B.)

Popped White Corn 88.57

Soy protein concentrate 8.19

Sodium carboxymethyl cellulose 1.46

Sugar 1.49

Acetylated monoglycerides 0.21

B-carotene 0.08

Table Ⅱ

Comparison of the comparison of glue and protein effects in corn slices WPC+CMC WPC+CMC+SPC WPC+CMC+SPC total protein ( %) 0.00 6.0 8.0 crispy 6.24 5.56b Crispy 6.63A 6.02B 5.56B oral solution /Disposter 4.56A 4.46A 3.88B sticky toothability 4.29 4.68 4.44 Oily/lipids 3.24 3.12 3.10 Rough sand texture 4.32A 4.22A 3.68B Oral adhesion 2.83 2.90 3.24 Overall flavor 5.24 5.02 5.24 Non -Signs 1.41.46 1.34 Sex 5.76 5.90 5.68 corn flavor 5.05 4.73 4.76 Salvation 3.93 4.27 4.24 Oil.

CMC refers to sodium carboxymethyl cellulose

SPC means soy protein concentrate

a, b and c refer to the apparent degree of difference between products

As can be seen from the data in Table II, increasing the protein content from 6% to 8% can reduce the gritty texture of the product, and at the same time achieve faster mouth dissolution.

Claims (8)

1. the frying cereal foods production method of extruding, its step comprises:

Grain flour and water are sent into extruder with protein source;

This mixture is extruded the formation dough, this dough comprises described grain flour of 70-95Wt% (with dry weight basis) and the described protein source of 4.5-25Wt% (with dry weight basis), this grain flour by non-pre-pasty cereal and remaining 0-40Wt% (with dry weight basis) roughly the cereal of 70-80% gelatinization constitute.

Described dough is pressed into band and this band is cut into a plurality of fragments that require shape; And

Described food is made in described fragment frying.

2. the method for claim 1, wherein said protein source is selected from soy protein concentrate and chorista, pea protein, corn protein, rice protein and milk proem matter.

3. method as claimed in claim 2, wherein said protein source are the soybean protein chorista.

4. the method for claim 1, wherein said extrusion step is carried out under 88-182 ℃.

5. the method for claim 1, wherein said frying step is carried out under 191-199 ℃.

6. the method for claim 1, the wherein said dough of extruding is cut into disc.

7. the method for claim 1, wherein said cereal is selected from corn, wheat, barley, buckwheat and rice and composition thereof.

8. method as claimed in claim 7, wherein said cereal is selected from white maize and yellow maize and composition thereof.