KR100540607B1 - Hydrolysis method of starch using ultra high pressure - Google Patents

Abstract

The present invention relates to a method for hydrolyzing starch using ultra-high pressure, and more specifically, i) adding an acid solution to starch to prepare a starch suspension; Ii) applying ultra-high pressure to the starch suspension for a predetermined time; And iii) performing solid-liquid separation on the ultrahigh pressure-treated starch suspension. When the starch is hydrolyzed by the starch hydrolysis method using the ultra-high pressure of the present invention, microbial sterilization, inactivation of enzymes, coagulation of proteins, natural flavor and taste of raw materials, Changes in nutrients, loss prevention, and starch gelatinization can be achieved.

Ultra High Pressure, Starch, Hydrolysis

Description

HYDROLYSIS METHOD OF STARCH USING ULTRA HIGH PRESSURE}

1 is a flow chart schematically showing a starch hydrolysis method using the ultrahigh pressure of the present invention and the physical property analysis process of the hydrolyzate

Figure 2 is a graph showing the content of the reducing sugar contained in the supernatant obtained by centrifugation of ultrahigh pressure corn starch suspension by adding hydrochloric acid, sulfuric acid and oxalic acid according to an embodiment of the present invention, respectively

3 is a graph showing the hydrolysis rate of starch treated with ultra high pressure by adding hydrochloric acid, sulfuric acid and oxalic acid according to an embodiment of the present invention, respectively.

Figure 4a, b, c and d is a scanning electron microscope (SEM) photograph of the precipitate obtained by ultrahigh pressure treatment by adding raw starch, hydrochloric acid, sulfuric acid and oxalic acid, respectively, and centrifugation

Figures 5a, b, c, d and e shows the precipitate obtained by ultrahigh pressure treatment of starch suspension added with raw starch, hydrochloric acid (5% starch), hydrochloric acid (20% starch), sulfuric acid and oxalic acid, followed by centrifugation. Micrograph of starch particles swelled and viewed at a magnification of 1,000 times

Figure 6a, b, c, d, e and f is shown by GPC to the molecular weight distribution of the supernatant obtained by centrifugation after the ultra high pressure treatment of the starch suspension of hydrochloric acid, sulfuric acid and oxalic acid solution of 5% and 20% Measurement result

Figure 7a is measured by the differential scanning calorimeter (DSC) thermal properties of the precipitate obtained by centrifugation after starch suspension of hydrochloric acid, sulfuric acid and oxalic acid solution containing 20% starch content 7b is a differential scanning calorific value for the thermal properties of precipitates obtained by centrifugation after ultra high pressure treatment to produce starch suspensions of 5-20% concentration to determine the starch concentration dependence using hydrochloric acid, which has the highest resolution during hydrolysis. Results of measurement

8A is an X-ray diffraction diagram of a precipitate obtained by centrifugation after starch suspension of hydrochloric acid, sulfuric acid, and oxalic acid solution containing 20% starch, and 8b is hydrochloric acid having the highest resolution during ultrahigh pressure hydrolysis. X-ray diffractogram to determine the initial starch concentration dependence of X-ray diffraction characteristics of precipitates obtained by ultrahigh pressure treatment after centrifugation

The present invention relates to a starch hydrolysis method, more specifically, iii) adding an acid solution to starch to prepare a starch suspension; Ii) applying ultra-high pressure to the starch suspension for a predetermined time; And (iii) performing solid-liquid separation for the ultrahigh pressure-treated starch suspension.

Starch is a large biopolymer that exists in nature in which glucose molecules are linked by α-1,4 and α-1,6 glucoside bonds, and supplies 70-80% of the calories consumed by humans. The method of producing starch hydrolyzate can be divided into acid glycosylation method which hydrolyzes into acid and enzyme glycosylation method which uses enzyme. Conventionally, the acid glycosylation method has been used a lot, but in recent years, the use of the acid glycosylation method is decreasing as many methods of obtaining a hydrolyzate by glycosylation as an enzyme.

  The acid glycosylation method of hydrolyzing starch molecules with acid is performed by mixing starch and acid solution and heating. The α-1,4 and α-1,6 glucoside bonds of starch molecules readily hydrolyze when heated with low concentrations of acid. At this time, since the hydrogen ions of the acid catalyzes, hydrolysis occurs faster as the concentration of starch as well as the higher concentration of hydrogen ions or higher reaction temperature. In the acid glycosylation method, in order for the hydrolysis to proceed completely, when the hydrogen ion of the acid acts as a starch molecule, water molecules must be present together, but even when the starch milk concentration is low, the starch molecules form micelles and thus cannot be dispersed evenly. There is a problem that the part having. In addition, the acid glycosylation method has a problem in that reverse synthesis occurs in proportion to the concentration of starch during hydrolysis. The ratio of glucose and inverted sugar produced depends on the starch concentration and temperature conditions, and the higher the starch concentration, the more reverse synthesis occurs. In addition, the acid glycosylation process requires a heating and cooling process, the energy cost is required, the process time is long, the productivity is reduced, there is a problem that the aroma and taste and nutritional ingredients of the raw material is changed and lost due to the heating.

On the other hand, glucoside (glucoside) binding of starch molecules are easily degraded by the action of enzymes, so there is an enzyme glycation method using starch degrading enzymes. Unlike the method of hydrolysis with acid, there is no need to neutralize the starch hydrolyzate after saccharification, and there is no need to remove salts generated during neutralization, and it has the advantages of high purity of glucose in saccharification solution and low production cost. Although it is mainly used for starch hydrolysis, grain starch itself is not pure and various enzymes work together to form various substances in the saccharification process, requiring a separate process for purification, and a general process using enzymes. Likewise, it takes a relatively long time, has difficulty in optimizing the reaction conditions, and the produced sugar has to be sterilized for long-term storage.

The effect of ultrahigh pressure on biopolymers is to reduce the space between molecules and to promote the reaction between chains. These ultra-high pressure technologies have not been widely used in the food industry yet due to the disadvantage of high equipment cost and limited amount of samples that can be processed at one time. The development of technology related to ultra high pressure treatment, such as increasing the amount of food, and the conventional method of heating, unlike other conventional heating processes, have shown that the advantages of minimizing the destruction of nutrients and maintaining the flavor of food during the ultra high pressure treatment are available in some countries such as fruit juice and It is used in limited food fields such as jelly. In addition, due to the advantage of sterilizing harmful microorganisms in foods without heat treatment, preserving the flavor of foods and improving shelf life, various studies related to this as part of a new non-heating processing method in advanced countries such as the United States and Europe are in progress. have.

For this reason, microbial sterilization and protein denaturation by ultra-high pressure treatment have been well established, whereas the application to other fields of ultra-high pressure treatment technology is insignificant. Recently, there have been some attempts to apply the ultrahigh pressure treatment technology to the starch processing field, and as a result, the results of the ultra high pressure treatment resulted in morphological changes of starch particles or gelatinization of starch [Katopo, H. et al., Carbohydr . Polym., 47, 233-244 (2002); Douzals, J. P. et al., J. Agric. Food Chem., 49, 873-876 (2001); Industrial Food Engineering 1 (3), 184-191 (1997), et al. However, research on the application of ultrahigh pressure treatment to starch is still very insignificant, and in particular, the contents of hydrolysis methods and properties of hydrolysates of starch using ultrahigh pressure treatment have not been described in any of the above documents.

Accordingly, the technical problem to be achieved by the present invention is to simplify and reduce the time and cost of the process, microbial sterilization, inactivation of enzymes, protein coagulation, changes and loss of natural flavors and flavors and nutritional ingredients of raw materials during processing. It is to provide a new method of hydrolyzing starch using ultra-high pressure that can be prevented, gelatinization of starch.

In order to achieve the above technical problem, the present invention comprises the steps of: i) adding an acid solution to starch to prepare a starch suspension; Ii) applying ultra-high pressure to the starch suspension for a predetermined time; And iii) performing solid-liquid separation on the ultrahigh pressure-treated starch suspension.

In addition, the present invention provides a method for hydrolyzing starch using ultra-high pressure, characterized in that the acid solution is at least one selected from the group consisting of hydrochloric acid, sulfuric acid, oxalic acid.

In addition, the present invention provides a method for hydrolyzing starch using ultrahigh pressure, wherein the acid solution is added in an amount of 3 to 30 times based on the weight of the starch.

The present invention also provides a method for hydrolyzing starch using ultra high pressure, wherein the ultra high pressure is 100 MPa or more.

Hereinafter, the present invention will be described in more detail.

The starch hydrolysis method using the ultrahigh pressure of the present invention includes the step of preparing an starch suspension by adding an acid solution to the starch. The starch used in the starch hydrolysis method using the ultrahigh pressure of the present invention is not limited, and all kinds of starches usable in conventional acid or enzymatic saccharification, for example, rice, wheat, barley, corn, potato, Sweet potatoes, cassava and the like can be hydrolyzed by the method of the present invention. The method for preparing the starch suspension is not different from the general acid glycosylation method and thus will not be described in detail herein. In preparing the starch suspension, the ratio of starch and acid solution may be adjusted by those skilled in the art to an appropriate range. The ratio of the starch and the acid solution is preferably an acid solution is added in an amount of 3 to 30 times based on the weight of the starch.

The acid solution is not particularly limited, and any known acid solution that can be used in the conventional acid glycosylation method may be used, and preferably one or more selected from the group consisting of hydrochloric acid, sulfuric acid, and oxalic acid.

The starch suspension is subjected to ultra high pressure treatment for a predetermined time. As described above, the ultra-high pressure treatment is one of the non-heating processing methods, and has been in the spotlight as a new processing technology capable of overcoming the texture and deterioration of the food by the conventional heat treatment. Ultra high pressure treatment is a technology that enables the sterilization, processing and cooking of foods, and Pascal's principle ensures that a given pressure is instantaneously and uniformly delivered through the pressure medium, water or oil. In the present specification, the ultrahigh pressure means a pressure of 100 MPa or more. In the present invention, the pressure applied to the starch suspension is preferably 100 MPa or more because the hydrolysis capacity is very low when the pressure applied to the starch suspension is less than 100 MPa. The time for adding the ultra high pressure to the starch suspension is preferably about 1 to 300 minutes. It is because the hydrolysis effect of this invention is insignificant when the time to apply ultrahigh pressure is less than 1 minute, and when it exceeds 300 minutes, process time becomes long and it is unpreferable.

The step of applying the ultra-high pressure of the present invention is preferably carried out in the range of 0 ℃ to 100 ℃, more preferably carried out in the range of 20 ℃ to 70 ℃. In order to perform ultra-high pressure treatment at a temperature below 20 ° C, a separate cooling device may be necessary.In general, at temperatures above 70 ° C, the taste and aroma of starch raw materials are deteriorated and side effects such as destruction of nutrients are concerned. Because it becomes. Since the starch hydrolysis method using the ultrahigh pressure of the present invention can achieve high conversion and starch gelatinization without heating to 70 ° C. or more, heating and warming, which are generally required in the conventional acid saccharification method or enzyme saccharification method. It does not require a cooling process, so it is possible to prevent the change and loss of natural flavors, flavors and nutritional ingredients of raw materials, and to save energy, simplify the process and improve productivity. In addition, the starch hydrolysis method using the ultra-high pressure of the present invention can achieve effects such as microbial sterilization, enzyme inactivation, protein coagulation, starch gelatinization due to strong pressure.

The starch suspension subjected to ultra high pressure treatment as described above is subjected to solid-liquid separation. The solid-liquid separation may be made by a known method, for example, membrane separation, filtration separation, flocculation sedimentation, flotation adsorption, centrifugation, etc., the viscosity of the suspension is significantly high and the productivity of the process through shortening of the process time Centrifugation is preferred in view of improvement.

 Hereinafter, the present invention will be described in more detail with reference to examples which are preferred embodiments of the present invention. However, the following examples are merely to help the understanding of the present invention, the scope of the present invention is not limited only to the following examples.

Example 1 Preparation of Starch Suspension Using Acid Solution and Ultra High Pressure Treatment

Twelve kinds of starch suspensions made of 100 g were prepared by adding 2N hydrochloric acid, sulfuric acid, and oxalic acid solutions to 5, 10, 15, and 25 g of corn starch (water content of 10.55%), respectively. The starch suspension was placed in a retort pouch and sealed. The retort pouch containing the starch suspension was placed in an ultra high pressure vessel (inner volume: 600 ml), filled with distilled water as a pressure medium, and then subjected to normal temperature (25 ° C) using an ultra high pressure vessel (model name: MFP-7000, manufactured by Mitsubishi Heavy Industries) ), Pressure was applied at 600 MPa for 30 minutes. After the ultrahigh pressure treatment, centrifugation was performed to perform solid-liquid separation. 1 is a flow chart briefly illustrating the physical properties of the starch hydrolysis method and hydrolyzate using the ultra-high pressure of the present invention.

For analysis, the supernatant of the centrifuged sample was stored in a separate container (bial) and refrigerated, and the precipitate was washed with distilled water, neutralized and dried by air drying. The dried precipitate was put in a mortar and ground and collected in 80 mesh (mesh sieve) sieve and stored in a deep freezer. The hydrochloric acid starch contained 9.09%, the sulfuric acid starch contained 9.88%, and the oxalic acid starch contained 9.46%.

Example 2 (Measurement of Reducing Sugar Content of Supernatant in Ultrahigh Pressure Starch Sample)

The content of the reducing sugar contained in the supernatant obtained by centrifugation in Example 1 was measured by the DNS colorimetric method of reducing sugar quantification. That is, the supernatant samples treated with hydrochloric acid, sulfuric acid and oxalic acid were neutralized with NaOH, CaCO ₃ and BaCO ₃ , respectively, diluted with the same amount of distilled water, mixed with 1 ml of diluent and 3 ml of DNS reagent, and then bathed in boiling water for 5 minutes. After cooling, the absorbance was measured at 550 nm using a spectrophotometer (Model name: Hitachi 220s). The absorbance values measured were converted to the amount of glucose by applying to a previously measured glucose standard curve. The experimental results are shown in Table 1 and FIG. As shown in Table 1, the content of the sample treated with 2N hydrochloric acid solution was measured in the range of 0.87 ~ 7.52mg / ㎖, the sample treated with 2N sulfuric acid solution in the range of 0.18 ~ 0.72mg / ㎖ reducing sugar In the sample treated with 2N oxalic acid solution, reducing sugar was measured in the range of 0.34-2.98 mg / ml. In addition, as can be seen in Figure 2, the content of the reducing sugar showed a tendency to increase as the content of the used starch increases.

Table 1 Content of reducing sugar in the supernatant separated in Example 1 (unit: mg / ml)

    Starch content 2N hydrochloric acid 2N sulfuric acid 2N Oxalic Acid 5 g 0.87 0.18 0.34 10 g 2.27 0.29 0.65 15 g 3.63 0.46 1.38 20 g 7.52 0.72 2.98

Example 3 (Measurement of hydrolysis rate of ultra high pressure starch)

In Example 1, the hydrolysis rate of the starch treated with ultrahigh pressure was specified. The precipitate obtained by centrifugation in Example 1 was dried by vacuum heating, and then the weight of the solid was measured. The hydrolysis rate was determined by calculating the ratio of the weight of the dry solid to the weight of the starch of the sample before treatment.

Equation 1 below shows a method for obtaining a hydrolysis rate.

[Equation 1]

Measured hydrolysis rate is shown in Table 2 and FIG. As shown in Table 2, the hydrolysis rate of the sample treated with sulfuric acid and oxalic acid ranged from 13.22 to 14.41%, and the sample treated with hydrochloric acid solution ranged from 42.76 to 47.24%. In addition, as shown in Figure 3, in all the acid did not show a difference in the hydrolysis rate according to the content of the starch.

[Table 2] Hydrolysis Rate of Starch (Unit:%)

Starch content 2N hydrochloric acid 2N sulfuric acid 2N Oxalic Acid 5 g 47.24 13.94 13.98 10 g 45.10 13.22 13.78 15 g 47.35 14.41 13.78 20 g 42.77 14.09 13.70

Example 4 Observation of Particle Shape of Ultra High Pressure Starch

The form of the precipitate obtained in Example 1 was observed with a scanning electron microscope (SEM, model name: Stereoscan 440, manufactured by Link ISIS) and an optical microscope (Olympus, model name: BX40-32H02). Figure 4 is a photograph of the precipitate obtained by centrifuging the ultra-high pressure starch sample was observed at a magnification of 2,000 times using SEM (Scanning Electron Microscopy) in the form of ultra-high pressure acid-treated starch particles dried. 5 is a photograph obtained by swelling the ultrahigh-pressure acid treated starch particles with distilled water under an optical microscope and observing them at a magnification of 1,000 times. Starch particle shape is characterized in that the hydrochloric acid starch partially breaks the starch particles as shown in FIGS. 4 and 5 in the state of maintaining the particle shape, unlike the acid-treated starch by heat, the higher the starch content The degree was severe, and the lower the content, the higher the proportion of the gel-forming part when swollen with distilled water. The sulphated starch was similar to raw starch, and the oxalic acid starch, which had a film form, did not retain the basic shape of starch particles when crushed, had a rough surface, and had swelled with distilled water. The shape is shown. In the case of oxalic acid starch, which shows the shape of gel, the hydrolysis of starch was less than that of hydrochloric acid, so it was judged that the ultrahigh pressure starch had different characteristics from gelation and starch hydrolysis. In other words, the gelation did not promote the hydrolysis of starch, and the gelation and hydrolysis due to the ultrahigh pressure is thought to be caused by other mechanisms.

Example 5 (Measurement of molecular weight distribution of sugars in the supernatant)

The molecular weight distribution of the supernatant obtained in Example 1 was measured by using a mixed solvent of H ₂ O: MeOH (1: 1) as a developing solvent and GPC (product of Younglin Instruments) adjusted to an elution rate of 1 ml / min. . Tables 3, 4 and 5 summarize the results obtained by measuring the molecular weight distribution of the supernatant obtained by centrifuging the ultrahigh pressure treated starch suspension by adding hydrochloric acid, sulfuric acid and oxalic acid solution, respectively. As can be seen in Tables 3 to 5, it can be seen that the higher the content of starch in the initial starch suspension, the higher the concentration of oligomer, which is a polymer material, in the sample. In addition, when hydrochloric acid was treated, glucose and maltose were hydrolyzed, but hydrolysis occurred with sulfuric acid or oxalic acid, but almost no glucose and maltose were detected.

TABLE 3 Molecular weight distribution of supernatant in hydrochloric acid starch sample

Starch content Peak Molecular Weight (Mw) area % Analysis 5% One 176808 2.79 Oligomer 2 24940 10.86 Oligomer 3 360 82.13 maltose 4 180 4.22 Glucose 20% One 141714 19.63 Oligomer 2 22612 28.86 Oligomer 3 1349 2.56 Oligomer 4 360 43.76 maltose 5 180 5.19 Glucose

TABLE 4 Molecular weight distribution of supernatant in sulfuric acid treated starch sample

Starch content Peak Molecular Weight (Mw) area % Analysis 5% One 1265 93.34 Oligomer 2 470 1.56 Oligomer 3 360 1.99 maltose 4 180 3.11 Glucose 20% One 1223 98.66 Oligomer 2 518 1.34 Oligomer

TABLE 5 Molecular weight distribution of supernatant in oxalic acid starch sample

Starch content Peak Molecular Weight (Mw) area % Analysis 5% One 889 100 Oligomer 20% One 391898 21.71 Oligomer 2 38214 12.33 Oligomer 3 623 65.96 Oligomer

Example 6 (Measurement of Thermal Properties of Starch Treated by Ultra High Pressure)

Thermal properties of raw starch and ultra-high pressure starch obtained in Example 1 (precipitated after centrifugation) were measured using a differential scanning calorimeter (DSC, manufactured by Perkin Elmer, model name: DSC-7). Measured. The sample was prepared when the concentration of starch in the starch suspension was 20%, and the measurement was performed by correcting the moisture content of the sample to 60%, placing it in a pan, and sealing it at 25 ° C to 130 ° C at a rate of 5 ° C / min. Heating was carried out to determine the crystal melting start temperature (T ₀ ), peak temperature (T _P ), termination temperature (T _C ) and crystalline enthalpy (ΔH, Joule / g). The results are shown in Table 6 below and FIG. 7A. In addition, in order to observe the concentration dependence of the ultra-high pressure starch, the thermal properties at the starch concentrations of 5%, 10% and 15%, respectively, were measured in the same manner as described above, and the results are shown in Table 7 and FIG. Shown in 7b.

As can be seen in Table 6 and FIG. 7A, the hydrochloric acid and sulfuric acid starch showed similar thermal properties to the raw starch when compared to the thermal properties of the raw starch, but ΔH was low in the hydrochloric acid starch. On the other hand, oxalic acid treated starch showed different thermal characteristics from raw starch, hydrochloric acid, and sulfuric acid starch, which was judged to be due to gel formation.

In addition, as can be seen in Table 7 and FIG. 7B, the higher the starch content, the higher the ΔH value was, but T ₀ , T _P , T _C and the like did not show a big difference.

Table 6 Gelatinization Characteristics of Acid Treated Starch Treated by Ultra High Pressure

T ₀ (℃) Tp (℃) T _C (℃) ΔH (J / g) Raw starch 62.39 71.77 89.73 13.34 Hydrochloric acid 20% 62.47 75.23 92.73 9.68 Sulfuric acid 20% 59.42 70.02 89.92 14.00 Oxalic Acid 20% 45.30 60.68 73.80 1.87

[Table 7] Gelatinization Characteristics According to Concentration of Hydrochloric Acid Treated Starch Treated by Ultra High Pressure

T ₀ (℃) Tp (℃) T _C (℃) ΔH (J / g) Hydrochloric acid 5% 62.55 76.862 87.56 4.75 Hydrochloric acid 10% 62.08 74.25 89.78 8.48 Hydrochloric acid 15% 62.32 78.28 93.29 8.64 Hydrochloric acid 20% 62.47 75.23 92.73 9.68

Example 7 (Measurement of X-ray Diffraction Pattern of Starch Treated with Ultra High Pressure)

X-ray diffraction patterns of the raw starch and the ultra-high pressure starch obtained in Example 1 were measured using an X-ray diffractometer (manufactured by Mac Science) to a diffraction angle (2θ) of 5 to 40 ° (see FIG. 8A). ). The sample was taken as the case where the starch concentration in a starch suspension is 20%. As shown in FIG. 8, peaks of X-ray diffractograms of hydrochloric acid starch and sulfuric acid starch showed peaks at diffraction angles of 15.0 °, 17.0 °, 17.7 ° and 22.8 °, respectively. There was no peak in the X-ray diffractogram of the starch. In addition, the lower the amount of starch, hydrochloric acid starch showed a tendency of smaller peaks due to the breakage of some crystalline regions, and the sulfated starch showed a diffraction pattern similar to that of raw starch regardless of the starch content. Regardless of the content of silver starch, gelatinization occurred and the crystalline region was destroyed, so that peaks did not appear.

As described above, when the starch is hydrolyzed by the starch hydrolysis method using the ultra-high pressure of the present invention, microbial sterilization, enzyme inactivation, protein coagulation and processing, together with simplification of the hydrolysis process and time and cost-saving effects Changes in the flavor, taste, and nutritional properties of the raw materials and the prevention of loss, and gelatinization of starch can be obtained.

The embodiments of the present invention described above should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

Claims (5)

Iii) adding an acid solution to starch to prepare a starch suspension; Ii) applying an ultrahigh pressure of at least 100 MPa to the starch suspension for 1 to 300 minutes; And Iii) starch hydrolysis method using ultra-high pressure comprising the step of performing solid-liquid separation for the ultra-high pressure treated starch suspension. The method of claim 1, The acid solution is a starch hydrolysis method using ultra-high pressure, characterized in that at least one selected from the group consisting of hydrochloric acid, sulfuric acid, oxalic acid. The method of claim 1, The acid solution is a starch hydrolysis method using ultra-high pressure, characterized in that added in an amount of 3 to 30 times based on the weight of the starch. The method of claim 1, The ultra high pressure is a starch hydrolysis method using ultra high pressure, characterized in that the pressure of 100MPa or more. The method of claim 1, The step of applying the ultra high pressure is a starch hydrolysis method using ultra high pressure, characterized in that carried out at a temperature in the range of 20 ℃ to 70 ℃.

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