JP2019014766A - Aquatic plant-derived novel starch - Google Patents

Abstract

To provide a novel starch.SOLUTION: Provided is a starch having a gelatinization temperature at a gelatinization starting temperature of 70°C or higher, a number average particle size of 2 to 3 μm, and an amylose content of 30 to 50%. In particular, a starch derived from duckweed. A starch in which the duckweed is one or more duckweed selected from flea duckweed, midget duckweed, duckweed, red duckweed (azolla), water hyacinth, button duckweed, giant canadian pondweed, midget canadian pond weed, water feather, and salvinia.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a novel starch.

  Japanese Patent No. 5569876 discloses a method for producing starch using a rice mutant.

  Japanese Patent Publication No. 63-052960 discloses a method for producing alcohol and methane using duckweed. Japanese Patent No. 4923167 discloses a method for recycling organic waste liquid using duckweeds. International publication WO2013 / 136663 pamphlet discloses a method for producing compost using palm oil residue and duckweeds.

Japanese Patent No. 5569876 Japanese Patent Publication No. 63-052960 Japanese Patent No. 4923167 International Publication WO2013 / 136631 Pamphlet

  As mentioned above, various starches have been proposed. Starch with new properties has new uses. For this reason, it is desired to obtain starch which is not conventionally known.

  In general, duckweeds are poor in the property of storing starch, and therefore duckweeds are not used to obtain starch. The present invention is basically based on the findings of the examples that starch derived from duckweed has unique physical properties not found in conventional starch.

The present invention relates to starch. This starch is
The gelatinization temperature is such that the gelatinization start temperature is 70 ° C or higher,
The number average particle size is 2 μm or more and 3 μm or less,
The amylose content is 30% or more and 50% or less.
This starch is preferably starch derived from duckweeds.
The duckweed is preferably one or more duckweed selected from the group consisting of daphnia, duckweed, duckweed, red duckweed (Azolla), water hyacinth, button duckweed, blue canard, cocanada, offofamo, and salamander.

  ADVANTAGE OF THE INVENTION According to this invention, the starch which has the specific physical property which did not exist until now can be provided.

FIG. 1 shows a photograph replacing a drawing when duckweed is harvested from a cultivation pond. FIG. 2 shows a photograph replacing a drawing which shows a state after standing for 5 minutes when the solid content 1 is left and separated. FIG. 3 shows a photograph replacing the drawing of the collected supernatant after resuspending the solid content 3 in water and adjusting the pH to 4.0, followed by stationary separation. FIG. 4 shows a micrograph in place of a drawing of the supernatant obtained by resuspending the solid content 3 in water, adjusting the pH to 4.0, and then separating it by static separation. FIG. 5 is a photograph replacing a drawing showing the observation results of starch granules by an optical microscope.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, but includes those appropriately modified by those skilled in the art from the following embodiments.

  The first aspect of the present invention relates to starch. A preferable example of this starch is starch derived from duckweeds. The duckweed-derived starch means starch obtained by using duckweed.

  Starch is a carbohydrate (polysaccharide) and is a natural polymer in which a number of α-glucose molecules are polymerized by glycosidic bonds.

Duckweed is an aquatic plant that grows in a floating state on the water surface. Duckweed hangs its roots in water and absorbs nutrients from the roots to grow.
The duckweed is preferably selected from the group consisting of daphnia, duckweed, duckweed, red duckweed (Azola), water hyacinth, button duckweed, giant canadian, cocanada, offofsamo, and salamander.

  Duckweed can be obtained by collecting duckweed from a water culture system in which duckweed is cultivated. For duckweeds, those cultivated in a water culture system to which palm oil wastewater is added may be used. Duckweed cultivated in a water culture system with added palm oil wastewater is rich in starch.

  It is preferable that duckweeds are those cultured using organic waste liquid.

  As for the physical properties of the starch of the present invention, the number average particle diameter is from 2 μm to 3 μm, and the amylose content is from 30% to 50%. The number average particle size is adjusted, for example, using a stainless steel test sieve (according to JIS Z8801-1: 2006), and then using a particle size distribution analyzer (Coulter LS-130) and ethanol as a dispersion medium. Just measure.

  The gelatinization start temperature of the starch of the present invention is preferably 70 ° C or higher. The gelatinization start temperature may be 70 ° C. or higher and 80 ° C. or lower, or 73 ° C. or higher and 76 ° C. or lower.

  Next, an example of a method for obtaining starch using duckweed will be described. This method basically includes a culture solution acquisition step, a first culture step, a recovery step, and a starch acquisition step. The second culture step is optional. Hereinafter, a method for obtaining starch using duckweed will be described based on a method including a first culturing step, a second culturing step, a recovery step, and a starch obtaining step in this order.

  The culture solution acquisition step is a step for obtaining a culture solution for cultivating duckweeds from the organic waste solution. Examples of organic effluents are palm oil effluent, human excreta-containing liquids or livestock excreta-containing liquids. Especially this invention can be preferably used in order to purify | purify a perm | palm extraction waste liquid. In other words, a large amount of waste oil from palm oil is a cause of environmental pollution. Using the present invention, it is possible to purify a storage pond of palm oil waste liquor produced in large quantities.

  The culture liquid acquisition process consists of anaerobic fermentation process for anaerobically fermenting organic waste liquid, a methane gas recovery process for recovering methane gas generated in the anaerobic fermentation process, and aerobic fermentation of the organic waste liquid anaerobically fermented by the anaerobic fermentation process. And an aerobic fermentation process for obtaining the above. An example of the period of the anaerobic fermentation process is 1 day or more and 30 days or less, and may be 5 days or more and 10 days or less. In the process of recovering methane gas, since methane gas is naturally generated, it can be recovered by a method of recovering gas. An example of the aerobic fermentation process is 1 day or more and 30 days or less, and may be 5 days or more and 10 days or less. Anaerobic fermentation can be achieved by adding organic waste liquid to the straw and generating methane gas.

  Another example of the culture liquid acquisition process is to repeatedly perform an anaerobic fermentation process for anaerobically fermenting an organic waste liquid and an aerobic fermentation process for an aerobic fermentation to obtain a culture liquid from the organic waste liquid.

  A 1st culture process is a process of cultivating duckweeds, adding a culture solution to a duckweed growth system. In this first culture step, duckweed grows and proliferates. An example of the period of the first culture step is not less than 1 week and not more than 3 months, and may be not less than 2 weeks and not more than 1 month.

  An example of a duckweed growth system includes a liquid storage unit composed of soil, and a duckweed and a liquid stored in the liquid storage unit. A specific example of duckweed growth systems is a pond that stores palm oil waste liquor. There are microorganisms in the soil. This microorganism contributes beneficially to the fermentation of duckweeds.

  The second culturing step is a step of cultivating duckweeds in a state where the addition amount of the culture solution is reduced as compared with the first culturing step. Thus, when the amount of the culture solution added is reduced, duckweeds stop growing and multiplying and store starch. An example of the period of the second culture step is 1 day or more and 1 month or less, and 5 days or more and 2 weeks or less.

  In the second culturing step, duckweeds are cultured in a state where the amount of the culture solution added is reduced to 1/10 or less of the amount of the culture solution added in the first culture step.

  In another example of the second culture step, duckweeds are cultured for 5 days or more in a state where the addition amount of the culture solution is reduced to 1/10 or less of the addition amount of the culture solution in the first culture step. .

  The recovery step is a step of recovering duckweed after culturing after the second culturing step. These recovered duckweeds become fertilizers when they are distributed as they are on farmland. In particular, these duckweeds can be effectively used as organic fertilizers because they contain a lot of organic phosphorus substances.

  A preferred example of the recovery step includes a step of recovering duckweed that has settled in the duckweed growth system. The settled duckweed is rich in starch. For this reason, organic waste liquid can be efficiently starched by recovering the settled duckweeds.

  In order to obtain starch from duckweeds, a known method may be used as appropriate. Examples of methods for obtaining starch are the sulfurous acid immersion method and the alkali immersion method. The alkali soaking method is to immerse the grain in an alkaline solution prepared with low-concentration alkaline chemicals, lime, grass ash, etc., soften the grain structure, dissociate starch and protein bonds, and remove starch from the grain. Separate and purify.

  In the alkali dipping method, for example, the cut duckweed is put as a raw material in a dipping tank containing a sodium hydroxide aqueous solution having a concentration of about 0.2% for the dipping solution. And the coupling | bonding of starch and protein dissociates by being immersed for 1-2 days. Thereafter, starch is prepared by wet milling. After the first dipping, only the dipping solution is replaced with a new alkaline solution, and dipping is repeated several times.

Duckweeds were harvested from cultivation ponds using a tamo net (net diameter 40cm, depth 60cm) in a 70L capacity hemp bag (Fig. 1). FIG. 1 shows a photograph replacing a drawing when duckweed is harvested from a cultivation pond.
As it was harvested, stones, mud, dead branches, and aquatic organisms were mixed in. Soaked in a pool filled with water and removed the contaminants.

  Duckweeds were collected using a stainless monkey (diameter 20 cm, depth 7 cm) and crushed in a colloid mill (Mounttech, PUC colloid mill). At the time of crushing, water equivalent to the wet weight of duckweed was added, and the crushing liquid was circulated until a uniform crushing liquid was obtained. The clearance at the start of crushing was set to 0.24 mm, and after crushing until the shape of the duckweed disappeared, the clearance was changed to 0.04 mm and continued for 5 minutes to collect the crushing liquid. Circulation was performed with a clearance of 0.24 mm. Part of the duckweed leaves remains. Circulation with clearance of 0.04mm.

  The collected crushed liquid is packed in a press bag (made by SAKAYA, PRESS BAG B1), squeezed and juice is separated to some extent, and then the cloth bag is pressed using a press machine (made by SAKAYA, Hydraulic Press B1 1PH). Juice was collected.

  The collected juice was collected as a solid content 1 by centrifuging for 5 minutes with a centrifugal force of 500G.

  Since this solid content 1 contains a large amount of fiber and protein, the process of suspending in water 10 times the weight of the solid content 1 and collecting the precipitate by centrifugation was repeated three times. After that, it was resuspended in 10 times the weight of the solid content and settled by standing for 5 minutes (Fig. 2). FIG. 2 shows a photograph replacing a drawing which shows a state after standing for 5 minutes when the solid content 1 is left and separated.

  Only the supernatant was recovered, and the solid content 2 was recovered by centrifugal concentration. Solid content 2 was put into a dryer at 50 ° C., dried to such an extent that cracks occurred on the surface, and then air-dried indoors.

  The dried solid 2 was suspended in water 10 times the weight of the solid 2 and the pH of the suspension was adjusted to 8.0 using 5N sodium hydroxide solution, and then the solid 3 was recovered by centrifugation. .

  Water of 10 times the weight of the solid content 3 was added, adjusted to pH 4.0 with sulfuric acid, stationary separation and centrifugation were performed, and the solid content 4 was recovered (FIGS. 3 and 4). FIG. 3 shows a photograph replacing the drawing of the collected supernatant after resuspending the solid content 3 in water and adjusting the pH to 4.0, followed by stationary separation. FIG. 4 shows a micrograph in place of a drawing of the supernatant obtained by resuspending the solid content 3 in water, adjusting the pH to 4.0, and then separating it by static separation. The collected solid content 4 was dried by air drying.

    26 g of solid content 2 having a starch content of 67.3% was recovered from 4 kg of duckweed having a solid content of 7.5% and a starch content of 7.6%. It was re-purified by alkali treatment and acid treatment, and 14 g of solid content 4 having a starch content of 97.2% was recovered. The starch recovery efficiency is 63%. The starch content was measured using Starch (HK) Assay Kit (manufactured by Sigma).

  The analysis results of duckweed starch (sample A, sample B) obtained in Example 1 are shown below. Sample A is a starch sample obtained from duckweed harvested in the morning, and sample B is a starch sample obtained from duckweed harvested at 16:00.

(1) Purification of duckweed starch Duckweed starch (sample A, sample B) was purified according to the method of Schoch. That is, the sample starch was repeatedly shaken and centrifuged using isoamyl alcohol / water (1: 3 (v / v)) to remove proteins and pigments in the sample. After thoroughly washing with water, it was transferred to a petri dish and the supernatant water was removed, dried thoroughly in a desiccator containing silica gel, ground in a mortar to form a uniform powder, and used in subsequent experiments.

(2) Measurement of moisture content The moisture content by the heat drying method was 11.0% for both Samples A and B.

(3) Measurement of blue value and maximum absorption wavelength obtained from iodine-starch composite absorption curve (Measurement of Sample A and Sample B)
The blue value (absorbance at 680 nm of the iodine-starch complex absorption curve) is a measured value affected by the apparent amylose content of the sample starch and the length of the side chain length of amylopectin, and the maximum absorption wavelength (λmax) of the absorption curve is mainly It is considered as a value that reflects the apparent amylose content.

  As a result of the measurement, the blue values of Sample A and Sample B were 0.55 and 0.50, and λmax was 598 nm and 592 nm, respectively.

  Compared with the results of one rice starch of cereal starch, the general blue values of mochi rice starch, uruchi rice (medium amylose rice) starch and high amylose rice starch are 0.07, 0.23, 0.33 and λmax are 526 nm, respectively. It was about 562nm and 590nm. Since the measured value of λmax was higher than that of rice starch, duckweed starch was a high amylose type, and since the blue value was higher than λmax, it was estimated that the side chain length of amylopectin was long .

  When compared with typical potato starches, the blue values of sweet potato starch and potato starch prepared from commercial potatoes were 0.35, 0.58 and λmax were 593 nm and 589 nm, respectively. From these results, it is estimated that the structure of duckweed starch is closer to that of potato starch, or potato starch than cereal starch.

  (4) Measurement of amylose content and amylopectin chain length distribution using an analysis method in which starch is debranched with isoamylase and then subjected to medium pressure gel filtration.

  The amylose content of the starch of sample B and the chain length distribution of amylopectin were examined by a conventional method by medium pressure gel filtration.

The content of Fr.I (corresponding to amylose fraction) is 31.9%, the content of Int.Fr. (intermediate fraction) is 7.8%, the content of Fr.II (long chain fraction of amylopectin) is 20.1%, Fr. The content of III (short chain fraction of amylopectin) was 40.2%, and the ratio of short chain to long chain of amylopectin (Fr.III / Fr.II) was 2.0. In the case of amylose content of rice starch,
Low amylose rice is 5-15%, medium amylose rice is 15-20%, high amylose rice is 25-30%, and the value of (Fr.III / Fr.II) is 2.5-3.0.

(5) Measurement of unit chain length distribution of the short region of amylopectin by anion exchange chromatography (HPAEC-PAD) using a pulsed amperometric detector

  As the side chain length of amylopectin was predicted from the blue value of iodine absorption curve and the result of medium pressure gel filtration, the side chain length distribution of the short chain region of amylopectin closely related to the gelatinization temperature Sample B was measured by the HPAEC-PAD method.

  Measure the amylopectin unit chain length distribution up to 50 mer, and detect the peak of the shortest chain region (6-12 mer; Fr.A) with respect to the total detection peak area from 6mer to 50mer. As a result of measuring the ratio (%) of the total area, the value was 11.1% lower than that of various known plant starches. (Amylose-extender (amylose-extender; ae) with amylopectin, 26-27% for regular rice starch, 22% for rice starch with high long chain, high gelatinization temperature, about 22%, extremely short chain and long chain ) Mutant rice starch was also 16%.) It was confirmed from the measurement results of many starches that the side chain length of amylopectin is long when the Fr.A content is low and the gelatinization temperature of the starch is high. Therefore, the gelatinization temperature of duckweed starch is expected to be very high.

(6) Observation of starch granules with an optical microscope Duckweed starch granules were observed with an optical microscope at a magnification of 400 times. The result is shown in FIG. FIG. 5 is a photograph replacing a drawing showing the observation results of starch granules by an optical microscope. In FIG. 5, sample A and sample B are denoted as sample (1) and sample (2). As a result, the starch granules were 2-3 μm, which was even smaller than the rice starch (diameter: about 5 μm) having the smallest particle size among the commonly available plant starches.

  Enzymatic digestibility with raw starch-degrading enzymes is generally known to be higher due to raw starch-degrading enzymes that degrade starch granules from the surface because the smaller the starch particle size, the greater the surface area per unit weight of starch. ing. Therefore, the enzyme digestibility of starch granules was examined next.

(7) Enzymatic digestibility of starch granules with crude glucoamylase agent Daviase K-27

Enzymatic digestibility of duckweed starch sample B was examined by a conventional method using a crude glucoamylase agent Daviase K-27 (Nagase Sangyo Co., Ltd.), which is a powerful raw starch degrading enzyme.

  Enzymatic digestibility was compared with normal corn starch (Ulchi corn starch; NCS) with a diameter of about 15 μm. First, 24 hours after the reaction, both duckweed starch and NCS of sample B were completely degraded to glucose. One hour after the reaction, the digestibility of duckweed starch was slightly higher, probably because the starch granules were small, but after that, the results showed that NCS with a small surface area per unit weight was highly digestible. This result suggests that duckweed starch granules have a structure that is more resistant to enzymes than NCS because they are less digestible than NCS, even though they have a sufficient surface area to contact the enzyme. It is done.

  (8) Measurement of gelatinization temperature and gelatinization heat of duckweed starch using a large-capacity differential scanning calorimeter micro DSC III

  The gelatinization temperature and the amount of gelatinization of duckweed starch were measured up to 115 ° C using a micro DSC III (Setaram, France) at starch: water (1: 2.5) at a heating rate of 1 ° C / min. The results are shown in Table 4.

  The starch whose gelatinization start temperature (To) of raw starch is close to 75 ° C, the gelatinization peak temperature (Tp) is 80 ° C or higher, and the gelatinization end temperature (Tc) is around 100 ° C is almost not found in other plant starches. Absent. Since To of commercial potato starch is 60 ° C., Tp is 64 ° C., and Tc is 71 ° C., duckweed starch begins to gelatinize after potato starch has been gelatinized. Although the heat of gelatinization (ΔH) was somewhat lower than about 18 J / g of potato starch, it showed a high heat of gelatinization equivalent to or higher than about 15 J / g of sweet potato starch.

  (9) Measurement of gelatinization temperature and gelatinization heat of aged duckweed starch using a large-capacity differential scanning calorimeter micro DSC III

  After measuring duckweed starch to 115 ° C as described above, duckweed starch is aged by allowing it to stand in a refrigerator (5 ° C) for 7 days together with the DSC container, and then gelatinizing temperature and gelatinization of the aged duckweed starch again The amount of heat was measured using a micro DSC III at a heating rate of 1 ° C / min. The results are shown in Table 5.

  The gelatinization peak temperature and gelatinization end temperature of aging starch are both extremely high for aging starch and the amount of heat for gelatinization of aging starch is high, which suggests that a large amount of strong aging starch was formed. In other words, it is considered to be an aging starch.

  Duckweed starch is a starch with high amylose content, extremely long amylopectin side chains, and very high gelatinization temperature. Therefore, it is easy to age, and it can be said that aged starch is very strong thermally.

(10) Viscosity measurement with Rapid Visco Analyzer (RVA)
Using RVA-4 (Newport Scientific, Australia), 30 ° C (1 minute), 30 ° C → 95 ° C (13 minutes, heating rate 5 ° C / min), 95 ° C (6 minutes) Hold), 95 ° C → 50 ° C (9 minutes, temperature drop rate 5 ° C / min), and 50 ° C (hold 10 minutes) temperature curve. Various characteristic values of the duckweed starches of Sample A and Sample B are as follows.

  First, the viscosity increase starting temperature is around 90 ° C, the highest among the known plant starches. This result shows an unusually high value of 90 ° C, although it can be predicted from the abnormally low value of Fr.A content investigated by the HPAEC-PAD method and the result of the high gelatinization temperature measured by DSC. Another reason is that the peak viscosity is as low as around 140 RVU. That is, the starch paste having a low viscosity is difficult to detect by the apparatus, so that the viscosity increase starts at a relatively high temperature.

  Moreover, since the peak viscosity and the minimum viscosity were almost the same value, the starch had an abnormally low breakdown. The setback showed a low value similar to waxy starch.

  Since duckweed starch is a high amylose type starch, it was surprising that setback, which has a high positive correlation with amylose content, was very low. In addition, since the heat of gelatinization of aging starch by DSC was high, it was expected to be aging starch, but the RVA setback value of aging starch was not consistent with the tendency to show a high value. It was. The reason for this is that duckweed starch is not sufficiently gelatinized by heating up to 95 ° C in an RVA container, and it is considered that the starch gel does not harden easily when the temperature drops from 95 ° C to 50 ° C. .

(11) Measurement of swelling power and solubility The swelling power and solubility of starch were measured by the following methods.

  Weigh accurately 50 mg of starch into a 10 mL spitz roll with a scale, add 10 mL of distilled water, set it on a block heater, adjust the block heater to a predetermined liquid temperature, and use a micro spatula to suspend the starch suspension in the spitz roll. After stirring the suspension for 30 minutes, the Spitz roll was removed from the block heater and cooled by immersing it in a container containing tap water for several minutes. After standing at room temperature for 1 day or more after that, the volume of glue became constant, and the swelling power was measured by reading the volume of glue with the scale of Spitzroll, and the total sugar content of the supernatant was measured by phenol / sulfuric acid method The solubility was calculated.

From the results of DSC and RVA measurements, it is known that duckweed starch has an unusually high gelatinization temperature and low viscosity. Therefore, the swelling power of lucid corn starch (NCS) as a control sample in increments of 75 to 10 ° C And solubility was measured.
As a result, as expected, duckweed starch does not gelatinize much until around 85 ° C, so its swelling power and solubility are lower than NCS, and even when heated at 95 ° C for 30 minutes, it does not swell and dissolve as much as NCS. It was confirmed.

From the above results, the following can be said.
Duckweed starch has a starch granule diameter of 2-3 μm, which is smaller than rice starch (5 μm), and is close to taro, millet amaranth, and quinoa starch (most of these very small starches have a high gelatinization temperature. (Starch of potato, wheat, barley, etc., even in the same starch sample, the gelatinization temperature of the small grains is higher than the large ones.) Duckweed starch can be used for high-grade paper coating instead of rice starch.

  Duckweed starch is less susceptible to the action of raw starch degrading enzymes for its very small grains. That is, duckweed starch has a grain structure with strong resistance to enzymes. Duckweed starch can be used as resistant starch.

  Duckweed starch has an unusually high gelatinization temperature. In other words, duckweed starch is difficult to gelatinize. Even if duckweed starch is processed at a high temperature, raw starch remains in the paste. Duckweed starch can be used as a paste with a unique texture.

  Duckweed starch has a high amylose content of over 30%. Duckweed starch has an unusually long amylopectin side chain. Duckweed starch can be used as a new food material as well as used as a starch for molding plastics and films.

  Duckweed starch is easy to age. Duckweed starch has a strong structure of aging starch. Duckweed starch can be used in vermicelli for aged foods. Duckweed starch can be used as a new food.

  Duckweed starch does not swell or dissolve even at high temperatures, and its viscosity is low even when gelatinized. For this reason, it can be used for an oblate, for example.

The present invention provides a novel starch and can be used in the food and chemical fields.

Claims (3)

The gelatinization temperature is such that the gelatinization start temperature is 70 ° C or higher,
The number average particle size is 2 μm or more and 3 μm or less,
Starch having an amylose content of 30% or more and 50% or less. The starch according to claim 1, wherein the starch is derived from duckweeds. The starch according to claim 2,
Starch, wherein the duckweed is one or more duckweeds selected from the group consisting of daphnia, duckweed, duckweed, duckweed (Azola), water hyacinth, button duckweed, giant canadian, cocanada, offofamo, and salamander.

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