INSTANT NOODLE FRIED WITH HYDROGENATED VEGETABLE OIL AND METHOD FOR MANUFACTURING THE SAME
Technical Field
The present invention relates, in general, to an instant fried noodle
(ramen) and, more particularly, to an instant noodle fried with hydrogenated vegetable oil, which retains its characteristic flavor for an extended period of time without deterioration. Also, the present invention is concerned with a method for manufacturing such a noodle.
Prior Art
At present, most of the instant noodle manufacturing and food processing industry uses palm oil in frying noodles. Palm oil has advantages of being plain in taste and relatively inexpensive. However, palm oil, though vegetable oil, is abundant in saturated fatty acid with a relatively low content of unsaturated fatty acid, like animal fat. Thus, palm oil is not favorable in nutrition.
Active research has been directed to the development of alternatives which are nutritionally beneficial with retention of the advantages of palm oil. According to the research results of the present invention, vegetable oil, such as soybean oil, corn oil, rice bran oil, cottonseed oil, canola oil, rape seed oil, sunflower seed oil, etc., may be used, (they are now being filed for patent). In addition to having high contents of linoleic acid, which is a necessary unsaturated fatty acid, these alternative oils are found to retain good flavor. These vegetable oils and fats, as they are, cannot be used to manufacture fried instant noodles: they exhibit poor oxidation stability owing to their high iodine values amounting to 1 10-130. To provide oxidation stability for the vegetable oils, hardening is needed, which can be achieved by hydrogenation. The vegetable oil which has undergone such hydrogenation (hereinafter referred to as "hydrogenated vegetable oil ") can be used in frying noodles. The noodle retains its own characteristic flavor, but it is naturally reduced to a significant extent with the lapse of time, so that the quality (flavor and odor) of the product is not conserved through its permittable storage and distribution period.
It was reported that the characteristic flavor of the noodle fried with hydrogenated vegetable oil is attributed to the formation of cis-6 nonenal and trans-6 nonenal upon hydrogenation, which originate from 9,15- or 8,15-octadecadienoic acid (Kepler, J.G., Schols, J.A., Feenstra, W.H., and Meijboom, P.W., 1965, Components of the hardening flavor present in hardened linseed oil and soybean oil, J. Am. Oil Chem. Soc, 42, 246- 249) or to the formation of trans, trans-2,6-octadienal (Yasuda, K., Peterson, R.J. and Chang, S.S., 1972, Identification of volatile flavor compounds developed during storage of a deodorized hydrogenated soybean oil, J. Am. Oil Chem. Soc, 52, 307-311).
Generally speaking, most of the characteristic flavor of the noodle fried with hydrogenated vegetable oil is ascribed to the aldehyde groups of the hydrogenated vegetable oil. Therefore, the reduction of the aldehyde groups causes a flavor reduction in the fried noodle, which actually takes place through the amino-carbonyl reaction between the aldehyde groups and the amino groups of the noodle, such as those from amino acids, peptides and proteins.
Disclosure of the Invention
The intensive and thorough research on the manufacture of instant fried noodles, repeated by the present inventors, resulted in the finding that the existence of the organic compounds able to react with amino groups in noodles inhibits the amino-carbonyl reaction which is an underlying cause of the flavor reduction of the instant fried noodle and thus, the mixing and kneading of noodle materials with the organic compound secures and retains the aldehyde groups contained in a hydrogenated vegetable oil, keeping the characteristic flavor of the instant fried noodle constant for a lengthy period of time.
Therefore, it is an object of the present invention to provide an instant fried noodle with a hydrogenated vegetable oil, which retains the characteristic flavor constant during its storage and distribution period in addition to being rich in nutrition and favorable economically.
It is another object of the present invention to provide a method for manufacturing an instant noodle fried with hydrogenated vegetable oil, which allows the inhibition of amino-carbonyl reaction in the noodle by the addition of edible organic compounds capable of reacting with amino
groups.
Best Modes for Carrying Out the Invention
In the present invention, an appropriate amount of an edible organic compound is added to raw noodle materials upon mixing and kneading, so as to manufacture an instant fried noodle with hydrogenated vegetable oil, which contains rich nutrition and is highly stable to oxidation without reduction of its characteristic flavor.
Examples of the vegetable oil useful to fry noodles with rich nutrition include soybean oil, corn oil, rice bran oil, cottonseed oil, canola oil, rape seed oil, and sunflower seed oil. Ranging, in iodine number, from 110 to 130, these oils are high in unsaturation and thus low in oxidation stability. Therefore, for use, they must be improved in oxidation stability, which is usually accomplished by hydrogenation. Preferable as a frying oil in the present invention is the vegetable oil which is hydrogenated to an iodine number of 50 to 100. For example, if the vegetable oil has an iodine number greater than 100, it is not stable to oxidation so that it readily undergoes rancidity. On the other hand, if the iodine number of the vegetable oil is below 50, it shows good oxidation stability, but suffers from a disadvantage in that it has a poor content of unsaturated fatty acid, deteriorating the quality of the product in a nutritional aspect. Thus, the hydrogenated vegetable oil preferably ranges, in iodine number, from 50 to 100.
The fried noodle of the present invention is manufactured by conducting (1) a mixing and kneading process in which raw materials, that is, 55-75 wt% of wheat flour, 10-20 wt% of starch, an edible organic compound at predetermined amount and 0.1-1 wt% of additives are kneaded in a mixing solution containing 2.5-4 wt% of a texture- improving agent, to give a dough; (2) a rolling and slitting process in which the dough is rolled into a sheet, followed by slitting the sheet into noodles; (3) a steaming process in which the noodles are waved under a steaming condition at a constant pressure and the noodle strands are gelatinized while some wave forms are fixed; (4) a cutting and shaping process in which the noodles are cut at a predetermined size and put in a shaping container (rectangular or circular); (5) a frying process in which the molded noodles are fried with a hydrogenated vegetable oil
with removal of moisture; (6) a cooling process in which the noodles are cooled with the aid of a compulsory blowing or ventilating means to make them suitable to be packaged as well as improve their preservativity; and (7) an inspecting and packaging process. Of the processes, the last two processes are the same as in conventional manufacturing methods.
In detail, in the mixing solution is added the edible organic compound which is able to form a chemical bond with the amino group (-NH2) contained in the raw noodle materials, such as wheat flour, starch and a texture- improving agent. As the compound which can perform such a function, there may be used reducing sugars, sugars which can be hydrolyzed into reducing ones, and various acidic amino acids and salts thereof.
Examples of the reducing sugars include glucose and fructose. The sugars which can have reducing ability through hydrolysis are exemplified by starch syrup. As for the acidic amino acids, they are preferably exemplified by glutamic acid and aspartic acid. Also, salts of these amino acids can be used with preference to monosodium L- glutamate (MSG). As previously illustrated, the edible organic compounds are involved in the chemical bond with the amino groups of the raw materials, which cause to reduce the characteristic flavor of the fried noodle during its storage and distribution period. Accordingly, the aldehyde groups of the hydrogenated vegetable oil have less a chance of bonding with the amino groups present in the raw material such as wheat flour, so that the characteristic flavor of the fried noodle can be retained for an extended period of time. Below, details will be given of the mechanism.
Whether being in a warehouse or in the market, the noodles fried with a hydrogenated vegetable oil gradually lose their characteristic flavor with the lapse of time. As aforementioned, because the characteristic flavor of the fried noodle is primarily based on the aldehyde that the hydrogenated vegetable oil contains, the flavor reduction can be illustrated by the aldehyde reduction resulting from the chemical bond between the aldehyde and the amino groups present in the raw materials. Thus, it is needed to eliminate amino groups, which play a pivotal role in reducing the flavor. In this regard, functional groups
which have a strong tendency to react with amino groups may be very useful to prevent the amino groups from bonding to the aldehyde. In accordance with the present invention, an edible organic compound which has such a functional group is added in the mixing and kneading process with the aim of significantly decreasing the possibility in which the amino groups meets the aldehyde. This can be illustrated by the following chemical formulas:
( enated oil)
(composite) (aldehyde of hydrogenated oil)
(acidic amino acids or salts thereof) (amino group) (aldehyde of hydrogenated oil)
(composite) (aldehyde of hydrogenated oil)
(wherein R, R' and R" each are all hydrocarbon groups)
By mixing and kneading the raw materials with the edible organic compound, as seen in the chemical formulas, the amino groups of the raw materials react with the functional groups of the edible organic compound to form composites, in advance of reacting with the aldehyde of the hydrogenated vegetable oil used in the frying process, resulting in prevention of aldehyde loss. Consequently, the characteristic flavor can be retained for a long period of time.
With respect to the amount of the edible organic compound to achieve this preventive reaction, reducing sugars and sugars which can be hydrolyzed into reducing ones, are preferably added at an amount of approximately 0.0003 to 0.3 wt% based on the weight of the fried noodle and approximately 0.001 to 1 wt% based on the weight of the mixing solution. As for the acidic amino acids and salts thereof, they are preferably added at an amount of approximately 0.003 to 0.3 wt% based on the weight of the fried noodle. Alternatively, their amount is preferably on the order of 0.01 to 1 wt% based on the weight of the mixing solution. For example, if the sugars are added at an amount less than 0.0003 wt% based on the weight of the fried noodle, there are expected no inhibition effects on the flavor reduction. On the other hand, if too much sugars are used, a strong effect of inhibiting the flavor reduction can be brought about, but the sweet taste of the edible organic compound itself possesses becomes strong, having a bad influence on the taste of the fried noodle. As in the sugars, the acidic amino acids and salts show no inhibition effects on the flavor reduction when they are added at an amount less than 0.003 wt% on the basis of the weight of the fried noodle. On the other hand, where the amino acids or salts thereof are used too much, there can be obtained a strong effect of inhibiting the flavor reduction, but the intrinsic taste of the amino acids or salts becomes too strong, reversely affecting the taste of the fried noodle. Where a fried noodle is manufactured by conducting a frying process using a hydrogenated vegetable oil, the aldehyde content in the hydrogenated vegetable oil is as small as or smaller than 1 ppm of the fried noodle, which is smaller by hundreds to thousands times than that contained in the edible organic compound added. Therefore, the amino groups contained in the raw materials have little chance to form a chemical bond with the aldehyde of the hydrogenated vegetable oil, but
are quite feasible to react with the edible organic compound, greatly contributing to inhibition of the flavor reduction.
A better understanding of the present invention may be obtained in light of the following examples which are set forth to illustrate, but are not to be construed to limit the present invention. For example, use of a combination of the edible organic compounds is also included in the scope of the present invention. In the following examples, a raw material composition comprising 55-75 wt% of wheat flour, 10-20 wt% of starch, 0.1-1 wt% of additives was kneaded, together with appropriate amounts of edible organic compounds, in a mixing solution containing 2.5-4 wt% of a texture-improving agent.
EXAMPLE I
Refined glucose was added at an amount of about 0.001 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 150 °C for 80 sec with hydrogenated corn oil.
EXAMPLE II
Refined glucose was added at an amount of about 0.01 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 154 °C for 60 sec with hydrogenated soybean oil.
EXAMPLE III
Refined glucose was added at an amount of about 0.1 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 154 °C for 120 sec with hydrogenated rice bran oil.
EXAMPLE IV
Glutamic acid was added at an amount of about 0.01 wt% in the mixing solution and kneaded, after which the resulting dough was
formed into noodles and fried at 154 °C for 120 sec with hydrogenated corn oil.
EXAMPLE V
Glutamic acid was added at an amount of about 0.02 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 150 °C for 120 sec with hydrogenated soybean oil.
EXAMPLE VI
Glutamic acid was added at an amount of about 0.04 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 153 °C for 80 sec with hydrogenated soybean oil.
EXAMPLE VII
Glutamic acid was added at an amount of about 0.1 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 154 °C for 60 sec with hydrogenated soybean oil.
EXAMPLE VIII
Monosodium glutamate (MSG) was added at an amount of about 0.01 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 140 °C for 90 sec with hydrogenated rape seed oil.
EXAMPLE IX
Monosodium glutamate (MSG) was added at an amount of about 0.02 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 145 °C for 85 sec with hydrogenated soybean oil.
EXAMPLE X
Monosodium glutamate (MSG) was added at an amount of about 0.04 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 160 °C for 60 sec with hydrogenated soybean oil.
EXAMPLE XI
Monosodium glutamate (MSG) was added at an amount of about 0.2 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 154 °C for 120 sec with hydrogenated soybean oil.
EXAMPLE XII
Aspartic acid was added at an amount of about 0.01 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 150 °C for 60 sec with hydrogenated soybean oil.
EXAMPLE XIII
Aspartic acid was added at an amount of about 0.02 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 153 °C for 60 sec with hydrogenated soybean oil.
EXAMPLE XIV
Aspartic acid was added at an amount of about 0.04 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 140 °C for 90 sec with hydrogenated soybean oil.
EXAMPLE XV
Aspartic acid was added at an amount of about 0.2 wt% in the mixing solution and kneaded, after which the resulting dough was formed into noodles and fried at 160 °C for 60 sec with hydrogenated soybean oil.
TEST EXAMPLE
For comparison of the flavor change, the fried noodles of the invention and a conventional fried noodle which contained no edible organic compounds were used as a test group and a reference group, respectively. To establish conditions comparative to summer weather conditions, which are the worst for the storage of noodles, the test group was stored for predetermined periods of time at 30 °C, together with the control group. A sensory test was conducted for the change in the flavor of the noodles by periods by skilled panels. In order to compare flavor, a control which was added with no edible organic compounds was in refrigeration for the same periods. Results of these sensory tests are given in the following tables.
TABLE 1 Flavor Change of Reference Group During Storage (at 30 °C)
* The control group was stored in a refrigerator.
* X: no change, o: slight change; ® considerable change
Refined glucose was used at an amount of 0.05 wt% and 1.0 wt% based on the weight of the mixing solution, to produce fried noodles which were stored as indicated in Table 2, below. The sensory test results are given in Table 2.
TABLE 2 Flavor Change During Storage (at 30 °C)
* The control was stored in a refrigerator.
* X: no change
Glutamic acid (GA) was used at an amount of 0.05 wt% and 0.1 wt% based on the weight of the mixing solution, to produce fried noodles which were stored as indicated in Table 3, below. The sensory test results are given in Table 3.
TABLE 3 Flavor Change During Storage (at 30 °C)
* The control was stored in a refrigerator.
* X: no change, Δ: slight change
Monosodium glutamate (MSG) was used at an amount of 0.05 wt% and 0.1 wt% based on the weight of the mixing solution, to produce fried noodles which were stored as indicated in Table 4, below. The sensory test results are given in Table 4.
TABLE 4 Flavor Change During Storage (at 30 °C)
The control was stored in a refrigerator.
* X: no change, Δ: slight change
As apparent from Tables 2, 3 and 4, the fried noodles which were produced by frying a noodle material added with a reducing sugar such as glucose, an acidic amino acid such as glutamic acid, or a salt of an acidic amino acid such as monosodium glutamate, with a hydrogenated vegetable oil, show little change in flavor even after expiration of the distribution period (shelf life) (150 days).
Industrial Applicability
As described hereinbefore, the edible organic compounds added in the mixing and kneading process in accordance with the present invention form chemical bonds with the amino groups which exist in raw materials and act to deteriorate the flavor of fried noodles, leading to inhibition of the amino-carbonyl reaction between the amino groups and the aldehyde groups of the hydrogenated vegetable oil. As a consequence, the fried noodle of the present invention has an advantage of retaining its characteristic flavor through the storage and distribution period without any deterioration in addition to being economically favorable by virtue of low production cost.
It is to be understood that the embodiments described herein are merely illustrative of the principles of the invention. Various modifications may be made thereto by persons skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.